14.45  Kryomätningar
    Dr. Erik Lind | E:3139

15-16 Tårta, öppet labb

2012-11-14 Ex-jobbspresentation: "Full system simulation of Near Field Communication"

Publicerad: 2012-11-06

On Wednesday Nov 14 at 10.15 in E:2349, Martin Magnusson will present his master thesis entitled
"Full system simulation of Near Field Communication".
The work has been conducted at Sony Mobile with Rune Sö as supervisor, and me as examiner at EIT.

Welcome!
Daniel Sjöberg

Abstract:
Near Field Communication (NFC) is a short range wireless communication technology that utilizes inductive coupling between coils. Important applications for NFC include wireless payment, tag reading, and peer-to-peer communication. Implementing NFC into a mobile device, such as a phone, requires an early set of predictions regarding the final performance and these predictions are becoming increasingly important for manufacturers. The main goal for this master thesis is to create a simulation methodology for predicting NFC performance in terms of a load modulated output signal. The simulation model covers both electromagnetic simulations of the NFC coils and the adjacent circuitry. Verification of the simulation model is tested by measurement on prototypes. A comparison of simulated and measured load modulation results confirms that they are of the same magnitude, i.e. the simulation model generates an output in the correct range. A difference in the component values needed for matching the NFC-coil to the control chip was also found. One component had a larger deviation than the rest when comparing a matching using an external matching board and a computer simulated matching. The concept for the simulation model works and the output provides resulting graphs with good trends and magnitudes of the individual values. The difference in matching comes from the use of a cable when measuring an external matching board compared to simulated matching.

2012-11-09 Seminarium: David Wall

Publicerad: 2012-11-07

Electromagnetic Theory research seminar: David Wall,
Department of Mathematics & Statistics College of Engineering,
University of Canterbury, Christchurch, New Zealand.

Title: Nonlinear wave propagation in the endothelium of human arteries

Friday November 9 at 15.15 in E:2349.

Welcome!
Mats Gustafsson

2012-11-09 Ex-jobbspresentation: "An embedded logic analyzer for post-silicon test and debug"

Publicerad: 2012-11-08

Jonas Johannesson and Philip Ljungkvist will present their master the is on
Friday Nov 9th at 11:00 in E:3139.
Tiltle: An embedded logic analyzer for post-silicon test and debug

Welcome!
Erik Lind and Joachim Rodrigues

Abstract:
Fabricating an ASIC is a complicated process with potential for errors. To know that the chip leaving the factory is working correctly, testing of the chip is necessary. Testing can be done by applying data to the input and compare the output with data that is known to be correct. The test data at the input needs to be carefully chosen to be able to detect as many errors as possible. Locating an error in the system not caused by the fabrication but rather by mistakes made by the designers is called debugging. To make debugging easier it’s important to have a high observability of the system so that it is possible to know where in the design something is not behaving as anticipated. In a pad limited ASIC the minimum area requirement is given from the amount of input and output pads rather than from the area requirements of the core. Being able to test a system without having to use a large number of input and output pads, can make the total area requirement of the system lower. The subject of this master thesis is to design a system capable of testing and debugging a circuit by using a serial connection. The serial connection reduces the required number of pins necessary and could thereby make the total area of the chip smaller. Because of the low speed of the serial connection, memories are used as buffers at the input and output of the tested system. The implemented system offers tools such as a triggering device and signal multi- plexers to make debugging of the system easier.

2012-11-08 Seminarium av Rebecca Seviour

Publicerad: 2012-11-07

"Tricking the light Fantastic..." | torsdag 8 nov kl 15.15 | E2311

På torsdag, den 8 november, ger Rebecca Seviour seminariet "Tricking the light fantastic". Sammandraget finner du nedan. Seminariet hålls i E2311 kl. 15.15. Vi serverar kaka kl. 15 i E2311, till er som närvarar. Så tag med din kopp till E2311, ta en bit kaka och lyssna till "Becky".

Rebecca, eller "Becky" som hon kallas, är Lise Meitner-professor på LTH till Juni 2013. Hon doktorerade på Fasta tillståndets fysik vid Lancaster universitet i Storbritannien och är nu professor vid Huddersfield universitet, i Storbritannien. Hennes forskning är fokuserad på fotoniska bandgapsstrukturer, metamaterial, och acceleratorer. Under det senaste året har hon varit involverad i designen av ESS.

Sammandrag:

From butterfly’s to accelerators, in this talk we examine how researchers inspired by nature are developing artificial materials to control the flow of light to create miniature particle accelerators. Discussing how accelerators work and some of the interesting properties of these novel materials. Finally we will discuss how accelerators contribute to today’s modern society and how miniaturising accelerators could help solve some of the biggest issues facing society.

Disputation Palmi Thor Thorbergsson

Publicerad: 2012-09-28

Datum: 2012-11-01, kl. 10.15

Plats: E:1406, E-huset, Ole Römers väg 3, Lunds universitet LTH

Opponent: Prof. Gaute Einevoll (Norwegian University of Life Sciences)

P. T. Thorbergsson: Signal Modeling and Data Reduction for Wireless Brain-Machine Interfaces
ISSN 1654-790X; No. 45, 2012.

Abstract:

Brain-machine interfaces (BMIs) provide a uni- or bidirectional communication link between the central nervous system and the outside world. This link facilitates the studying of neuronal mechanisms underlying behavior as well as the treatment of neurological disease. Wired BMIs are limited in the sense that they restrict the mobility of the subject and they increase the risks for post-surgical complications. While wireless BMIs ideally solve these problems, their designers face the challenge of combining high information throughput with limited wireless link capaci ty and energy resources. Therefore, measures have to be taken to maximize the utilization of the wireless link and energy resources by designing computationally eff icient and reliable data reduction techniques. The design and validation of such techniques requires the presence of well defined test data, where the true information content is known a priori. This thesis deals with both the modeling of the neural signal to provide realistic and practical means of generating test data, as well as low-complexity methods for data reduction that lead to efficient utilization of the wireless link and the energy resources at hand. The main part of the thesis is a collection of papers that address these aspects.

Paper I presents the design and implementation of a simple telemetry system for the wireless transmission of neural data from four measurement channels. This paper highlights some of the design challenges that need to be considered and thereby serves as a pilot investigation fo r the following papers.

Paper II presents a recording model and a simulation tool for generating single-channel test recordings for the validation of algorithms for spike detection and spike sorting. Having set up the geometry of the recording, each neuron is assigned a random spike waveforms from a library of experimentally obtained templates. The contribution of each neuron is generated by adding the corresponding waveform at randomly generated spike times and the spike trains are added up to form the entire recording. Spike times are modeled by a renewal process. The model is evaluated in terms of realism by comparing the power spectral density and autocorrelation of synthetic biological noise generated by the model, to noise obtained from real recordings.

Paper III extends the finite spike library provided in paper II in order to provide a greater, still realistic, variation in spike waveforms. Principal component analysis and Gaussian mixture models are used to model the statistical properties of the original spike library and the statistical model can then be used to generate an arbitrary number of spike wavforms with realistic properties. The extension is shown to be usable in providing access to arbitrarily large libraries of spikes with realistic properties.

Paper IV uses the models presented in papers II and III to explore the effects of sampling rate and resolution on the performance in spike detection and spike sorting at various noise levels and numbers of target neurons. Performance curves are analyzed to find sampling rate and resolution breakpoints for spike detection and spike sorting. These breakpoints serve as guidelines for selecting sampling parameters when dimensioning wireless BMIs. The paper presents methods for quantifying the accuracy in spike detection and spike sorting and provides general insight into how the performance of these processing tasks are influenced by sampling parameters, noise level and number of target units.

Paper V presents a preliminary study of the characteristic relationship between physical electrode movements and movements of detected spikes in feature space, using the signal models presented in paper VI. We then model this relationship as a linear transformation between two coordinate systems and show that given that a training procedure is introduced at the time of electrode insertion, future electrode movements can be estimated directly from the feature space representation of spikes.

Paper VI presents a new, computationally and memory efficient approach for modeling the extracellular signal. We use traditional compression techniques and polynomial fitting to derive a deterministic model that can be used for fast calculation of spike waveforms in arbitrary measurement points surrounding a compartment model of a neuron. Four different neuron models are derived and they are all shown to accurately predict the spike waveforms produced by the original compartment model, both in terms of spike shape and amplitude. The model is implemented into a simulation tool that efficiently and realistically synthesizes recordings with multielectrode arrays of arbitrary geometries.

Paper VII addresses low-complexity methods of compressing detected spike waveforms in wireless BMIs to ensure efficient use of the wireless link and energy resources at hand. The paper shows that given the correct choice of overall system architecture and spike detector, spike waveforms can be compressed with fixed generic compression bases, derived from experimentally obtained spike libraries, without significant loss in accuracy in spike reconstruction and sorting.

SLTC 2012

Publicerad: 2012-09-27

The Fourth Swedish Language Technology Conference

October (24-)25-26, 2012

Keynote speakers:
Martha Palmer, University of Colorado, Boulder
Fred Roberts, Artificial Solutions, Hamburg

See call for papers at http://nlp.cs.lth.se/events/sltc_2012

Contact: sltc2012@cs.lth.se

Swedish Communication Technologies Workshop

Publicerad: 2012-09-28

24-26/10, E-huset.

Welcome to Swe-CTW 2012!
The 2012 Swedish Communication Technologies Workshop (Swe‐CTW 2012) will be held at Lund University on 24‐26 October 2012. Swe‐CTW 2012 will bring together researchers and research students in the general area of communication technologies and related areas. The three day workshop provides an opportunity for researchers and research students to gather in a largely informal setting to share ideas, make contacts, and foster new collaborative links for the future. This year's workshop is based on Swe‐CTW held in Stockholm last year and modelled on similar successful events in Denmark and Australia, emphasizing the active participation of young researchers and research students. In addition to the workshop, there will be two half-day tutorials on 24 and 26 October, respectively.

The deadline for submitting an abstract for a poster presentation at Swe-CTW 2012 is October 12. More info at http://www.ee.kth.se/swe-ctw-2012

2012-10-22 Ex-jobbspresentation: “A Feasibility Study of PreAmplifier Design for Hearing Aid”

Publicerad: 2012-10-17

On Monday 22 October at 10:15 in E:2311, Usman Farooq will present his Master’s thesis titled:
“A Feasibility Study of PreAmplifier Design for Hearing Aid” The work was performed at GNResound in Denmark.

You are most welcome to attend the presentation!
Henrik Sjöland

Abstract:
The trend of scaling down the mixed signal integrated circuit (IC) technologies is on one hand facilitating the digital circuits to fully embrace the smaller feature sizes but on the other hand it severely limits the performance of analog circuits. This poses a tough demand for analog circuits to give comparable and acceptable performance in a CMOS technology with higher threshold voltage compared to available supply voltages. This work describes the design, implementation and simulations of low-voltage and low power PreAmplifier in 65nm CMOS technology. The PreAmplifier is used in the front-end of a hearing aid and its gain is digitally controlled based on input signal power level. The gain is programmable in steps of 6 dB ranging from 0 to 24 dB i.e. 0, 6, 12, 18 and 24 dB with less 1% gain variation from the specified values. The designed PreAmplifier primarily consists of a two Stage Miller compensated operational amplifier. It uses switched capacitor technique to implement the feedback resistor around the operational amplifier. The lower cutoff (-3dB frequency) of the specified bandwidth for the PreAmplifier is simulated to be 100Hz for all gain configurations. The power supply rejection ratio (PSSR) is -45dB, the total input referred voltage noise is -107 dBV, and the total harmonic distortion (THD) is -87dB. The total current consumption of the PreAmplifier with 1V power supply is 32μA. All the simulations of PreAmplifier are performed using Analog Design Environment tool of the CADENCE at 27° C and the load capacitance of 1pF. The approximate chip area of the designed PreAmplifier is 250μm x 250μm.

Disputation Johan Löfgren

Publicerad: 2012-09-27

Datum: 2012-10-19, kl 10:15
Plats: Lecture hall E:1406, E-building, Ole Römers väg 3, Lund University Faculty of Engineering
Opponent: Professor Keshab Parhi. Department of Electrical and Computer Engineering, University of Minnesota, USA
J. Löfgren:
Hardware Architectures for Wireless - Communication Symbol Detection and Channel Estimation
ISSN 1654-790X; No. 44, 2012.
Abstract: In this thesis different aspects of baseband implementation of mobile communication systems is treated. The content is focused on symbol detection and channel estimation in MIMO and OFDM. The thesis deals with the complete chain from algorithm to silicon implementation within these areas.

The main contribution of this thesis is described in the included papers. The first paper handles symbol detection in MIMO communication. The paper shows ways to improve on the K-Best detection strategy from a hardware perspective. It focuses on how the inherent orthogonality between the real and the imaginary part of the complex number can be used. To do this a modified real-value decomposition is proposed together with a number of algorithm simplifications.

The second and third papers discusses a channel estimation algorithm known as Robust SVD channel estimation. This estimator can reach performance close to that of an MMSE estimator with a substantially reduced complexity. Paper II describes architectural considerations of the estimator and shows the implementation feasibility of the approach. In Paper III a hardware estimator architecture is presented, together with implementation data in a 130 nm process. The synthesized area is 1.38 mm2 with a maximum frequency of 179 MHz and a simulated average power dissipation of 14.2 mW.

In the fourth, fifth, and sixth paper another channel estimation algorithm, using matching pursuit, is analyzed and implemented. In Paper IV an improved matching pursuit algorithm is presented. It performs equally well to its predecessors while the complexity is reduced. The number of multiplications in the core estimation is reduced by ?40 %. However, the algorithm requires a non-powerof-2 FFT/IFFT, with radix 3 and radix 5 units. Paper V describes the general strategy for implementing these type of FFT/IFFTs. It is seen that the complexity increases slightly when using radix 3 and radix 5 units but not dramatically. The number of multiplications per input data for a 52324 = 1200 point FFT is 14.1. This should be compared with 10.5 for the 210 = 1024 point and 12.0 for the 211 = 2048 point radix 2 FFTs respectively. Finally Paper VI describes the full implementation of the improved matching pursuit estimator, including the FFT/IFFT. Implemented in a low power 65 nm process, the estimator can be fit in an area of 1 mm2 and run at 70 MHz. The power dissipated is simulated to ?13 mW at 50 MHz.

2012-10-12 Ex-jobbspresentation: “Determination of Border Traps in InAs Nanowire Transistors”

Publicerad: 2012-10-10

On Friday 12/10 10.15 in E2349, Jiantuo Gan will present his Master thesis, entitled “Determination of Border Traps in InAs Nanowire Transistors”.

Everyone is most welcome!
Erik Lind

Short abstract:
In this thesis, we have successfully built up a new type of electrical circuit with lock-in amplifer to measure the transconductance at low frequency up to 100 kHz and VNA from 20 kHz upwards, from which we obtained the border trap density at the order of ~ 1027 m-3/eV for HfO2 gate wrapped InAs nanowire transistor S06A-E2 at 1 ~ 2 nms far from the interface. In the meantime, we proved that bilayer structure of HfO2 with internal layer of 0.5 nm of Al2O3 can effectively reduce the border trap density for an InAs nanowire.

Lund Circuit Design Workshop

Publicerad: 2012-07-03

The Lund Circuit Design Workshop, October 3-4, 2012, will be held at Grand Hotel and Faculty of Engineering, Lund University. The workshop is hosted by the VINNOVA Industrial Excellence Center SoS and by the SSF Strategic Research projects Wireless Communication for Ultra Portable Devices and Wireless with Wires.

Mer information

2012-10-05 Ex-jobbspresentation: "Design and Implementation of a D-Band Quasi-Optical Permittivity Measurement System"

Publicerad: 2012-10-03

On Friday 5/10 at 10.15 in E:2349, Doruk Tayli will present his master thesis entitled
"Design and Implementation of a D-Band Quasi-Optical Permittivity Measurement System"
The work was performed at Sony in Germany, and has been supervised by Marcel Blech at Sony.

Welcome!
Mats Gustafsson

Abstract:
This thesis describes the design, simulation, and implementation of a quasi-optic permittivity measurement system for the D-band. Complex permittivity is an important parameter for applications that rely on precise measurements results such as; remote sensing, and stealth technologies. This work presents a permittivity measurement system for the 130-150GHz frequency range, where complex permittivity databases are not available publicly. The permittivity measurement system is designed using the quasi-optical technique that simplifies mm-wave design. After the initial system specifications are determined with the quasi-optical theory, individual components, the horn antenna, and lenses are designed. These designs are simulated using CEM, the simulation results are compared to the design specifications and important differences are stated. The designed components are manufactured to implement the system. The antenna is manufactured using a novel technique that allows the construction of corrugated horn antennas for mm-wave frequencies. The far-field measurement results for the manufactured corrugated horn antenna shows little discrepancy from the simulation results, varying by a maximum of 1dB for the beamwidth of interest. The initial measurements also show that, the designed components comply with the design specifications. The TRL calibration for the free-space measurement system and the TRL algorithm is explained in detail. A quasi-Newton optimization technique is described to extract the permittivity from measured S21data. This work describes the design and implementation process, including the manufacturing point of view, of a quasi-optical measurement system in detail.

2012-10-02 Ex-jobbspresentation: "Simulation and verification methodology of mixed signal automotive ICs "

Publicerad: 2012-09-27

On Tuesday Oct 2nd at 15:15, place: E:2311, Banafsheh Rezaeian will present her master thesis.
"Simulation and verification methodology of mixed signal automotive ICs"
The project was conducted at Infineon in Munich.

Welcome!
Joachim Rodrigues

Abstract:
The Universal Verifi cation Methodology standard provides immense advanced automatic techniques to the digital verifi cation world. In fact without mechanisms like constraint random stimulus generation, functional coverage and self-checking testbenches, functional verifi cation of today's complex integrated circuits is not conceivable. While digital verification benefi ts from all these modern methods, analog verifi cation is still a manual process. This report presents a new verification approach in order to simulate mixed-signal designs through utilizing sophisticated methods used in digital verifi cation. The developed verifi cation technique in this work makes it possible to simulate a DUT with both digital and analog interfaces using event driven simulators. This method is compatible with existing digital veri cation techniques. The aimed DUT contains RTL and RNM blocks. As transaction level modeling a ffects digital verification to a great extent, analog transaction level modeling is exploited in this work to achieve more facile strategies in challenging mixed-signal verifi cation.

2012-10-01 Ex-jobbspresentation: “Nanoantennas”

Publicerad: 2012-09-28

On Monday Oct 1 at 15:15 in E:2349, Farhad Shokraneh will present his master thesis on “Nanoantennas”. Mats Gustafsson has been the supervisor, and I act as the examiner.

Welcome!
Daniel Sjöberg

Abstract
The concept of antennas at optical frequency has opened up new fields of experimental and theoretical research in nanotechnology and wireless communications. The growing interest in optical antennas and nano scale metals can be attributed to their ability to support plasmon resonances that interact with optical fields. The remarkable advances of nanotechnology experienced in recent years have increased the interest in optical antennas as devices for efficiently manipulating light by means of their optical properties such as concentration, absorption and radiation of light at nano-scale. In particular, numerous research have been recently done on this topic, suggesting how different materials and geometries of nano particles may be employed as nano antennas at optical frequency and the results are hoped to be able to unveil many current unknowns in medicine, physics, wireless communications, chemistry, biology, etc. The optical properties of a nano antenna is highly dependent on its size, geometry and the material. Since, this novel technology is in its early stage and has a lot to be investigated, reducing the size of an antenna down to nano scale which is intuitively corresponded to an increase in the operation frequency, might still be a challenging task to design, fabricate and characterize their resonant behavior. This work is an approach to optical properties of nano antennas and the effect of size, shape and material. The dispersion of metals at optical frequencies is described by the Drude-Lorentz model. In addition, the role of surface plasmon polariton resonances in the resonant characteristics of nano antennas is studied.

2012-09-20 Tårtseminarium med Björn Landfeldt

Publicerad: 2012-09-14

På torsdag, dvs. den 20 september, är det dags för höstens första tårtseminarium. Titeln på föredraget är ”There and back again, and again, and again!”.

Björn Landfeldt. Foto: Johan Cedervall

Föredragshållare är Björn Landfeldt och hans sammanfattning av föredraget är:

Well, in line with the purpose of the cake talk tradition, I will try to introduce myself to the people of the E-building, providing some more or less amusing tales along the way. I guess I have now reached the age at which I am invited to reminisce, like a fine wine. I will look back to the times that formed my interest in science and engineering going through my continent hopping and ending up in a forward gazing where I talk about what I find interesting now and what I think I will find interesting in the future.

So, come join me on a journey there and back again, and again and again.

Tårtseminariet startar klockan 14.06, i E1406.

2012-09-19 IT möter Nanoteknik med Lars-Erik Wernersson

Publicerad: 2012-09-07

IVA Syd inbjuder till möte på Lunds tekniska högskola den 19 september 2012.

Lars-Erik Wernersson.

IT möter Nanoteknik: NanoRadar, NanoKommunikation, NanoAntenner och små NanoKretsar

Många innovationer är baserade på nya materialteknologier som genererar oväntade tillämpningar. Idag introduceras till exempel allt fler material i kiselteknologin och vi ser en ökad prestanda i transistorerna. Men materialintegrationen erbjuder även andra möjligheter som att skapa korta koherenta pulser vid höga frekvenser.

I denna presentation kommer jag att ge exempel på hur nya material introduceras i transistorer för att öka prestandan samt hur små kretar designas för att skapa väldefinierade och korta pulser, så kallade ”wavelets”. Pulserna finner användning inom högupplöst radar samt för direkt kommunikation med hög dataöverföringshastighet.

Tillsammans med små antenner erbjuder nanoteknik här möjlighet att skapa energieffektiva system i gränslandet mellan GHz och THz applikationer.

Medverkande är Lars-Erik Wernersson.

Välkommen!
Lennart Fredenberg, ordförande IVA Syd
Ulla Svantesson, sekreterare IVA Syd

Anmälan och mer information
Tid: Onsdagen den 19 september 2012, kl. 17:30–19:00.
Plats: Lunds tekniska högskola, E-huset, lokal E:1406, Ole Römers väg 3, Lund.
Anmälan: Anmälan görs senast den 12 september till us@iva.se.
Mer info: Kontakta Ulla Svantesson, e-post us@iva.se, tel 08-791 29 93.

2012-09-18 Ex-jobbspresentation: "Real-time monitoring and prediction of Internet video"

Publicerad: 2012-09-14

On Tuesday 18/9 at 10.15 in E:3139, Jordi Rey Morales will present his master project titled
"Real-time monitoring and prediction of Internet video".
The project has been performed in cooperation with Acreo AB in the IPNQSIS project.

You are all welcome!
Maria Kihl

Abstract
Video Internet services are increasing every year. High-Quality TV over Internet is a service offered by many companies in many countries, and video streaming websites are within the most popular sites on the Internet. Because of that, service providers have a major concern in giving to their customers the best quality in their services. In order to guarantee the quality on these services, a Quality of Experience monitoring tool is required. The main goal of this thesis is to develop a tool to monitor the Quality of Experience of video over Internet services. In order to be functional, this monitoring tool has to be usable in a real scenario. In this case, a real scenario implies that this tool is used in strategic points of the network and the only available means is the data stream that goes through the network. The most important feature of this tool is that it has to be functional in real-time. It has to be so because its goal is to detect problems before these affect the quality of the video offered to the customers and avoid their complaints. In this thesis a lightweight method to monitor the Quality of Experiences is implemented. It is designed to predict in a fast way the quality of the video using only the data stream: information in the Internet protocols headers and in the coded video data. In order to achieve this, the structure of the packets has been studied, including the format of the protocols headers and the video codec encoding performance. Then the software has been designed to receive the stream and calculate the parameters that give an estimation of the Quality of experience. This method has been tested to validate its performance and conclude whether it is or not a valid tool to be used in a real scenario or not.

2012-09-14 Ex-jobbspresentation: "Sensor Network Optimizations Using Software Defined Radio Techniques"

Publicerad: 2012-09-10

På fredag kl 13.15, i E:2311, kommer följande examensarbete att presenteras
Titel: Sensor Network Optimizations Using Software Defined Radio Techniques
Författare: Ziyang Li & Zhonghua Wang
Utfört hos: SICS, Stockholm

Välkomna!
Ove Edfors

2012-09-14 Ex-jobbspresentation: "Assessment of realistic output power levels for LTE devices"

Publicerad: 2012-09-13

On Friday 14/9 at 10.15 in E:2349, Paramananda Joshi will present his master thesis entitled

"Assessment of realistic output power levels for LTE devices"

The work was performed at Ericsson Research in Kista, Stockholm, and has been supervised by Tomas Persson Ericsson Research.

Welcome!
Mats Gustafsson

Abstract:
Human exposure to Radio-Frequency (RF) Electromagnetic Field (EMF) is generally specified in terms of Specific Absorption Rate (SAR), which is defined as the rate of absorption of RF energy and is expressed in watt/kg. Human EMF exposure expressed as SAR is directly proportional to the device RF output power. In this thesis work, relative Electromagnetic Field (EMF) exposure levels for different applications using a Long Term Evolution (LTE) device was assessed through measurement of device Radio Frequency (RF) output power using the TEMS Investigation (TI) 13.1.32 system. Some real and everyday use applications like Voice Over IP (VOIP), Multimedia streaming, and file transfer using File Transfer Protocol (FTP) were included to find realistic exposure levels of the device during typical usage. Furthermore, an application comparable to voice data rate was also emulated for comparison with 2G and 3G voice calls. Drive tests were performed in urban, suburban, and rural areas in and around Stockholm. Some indoor and outdoor walk tests also were conducted. Overall, the average uplink output power for LTE was found to be well below the maximum output power (200 mW) for all applications. The FTP application, having the highest physical throughput, resulted in the highest RF output power among all the tested applications. In non-rural areas, the mean output power for this application was found to be about 8 times below the maximum output power. The corresponding figure for rural areas was 3 dB. Other applications, having lower throughput values, were found to have substantially lower output power levels compared to the FTP application.

2012-09-11 Lunchseminarium: "Mobil kommunikation - En svensk världsmästargren"

Publicerad: 2012-09-06

Tisdag 11 september, 12.15 - 12.45 i hörsal E:A

Lunchsemiarium om Mobil kommunikation - En svensk världsmästargren
med Stefan Parkvall, expert hos Ericsson Research.
En av personerna bakom dagens 3G och 4G.
Vinnare av Stora Teknikpriset.

Anmäl er på www.eit.lth.se/lunch
Lunchbaguette och dryck direkt efter seminariet OM du anmält dig före kl 11.30 måndag 10 september!!!!

VÄLKOMNA

2012-09-10 Ex-jobbspresentation: "Microwave materials characterization using waveguides and coaxial probe"

Publicerad: 2012-09-05

On Monday 10/9 at 15.15 in E:2349, Christos Tsipogiannis will present his master thesis entitled "Microwave materials characterization using waveguides and coaxial probe"
The work was performed at the EIT department, and has been supervised by Daniel Sjöberg and Christer Larsson, with Mats Gustafsson as examiner.

Welcome!
Daniel sjöberg

Abstract
"The complex permittivities of some liquid and solid samples have been measured using a reflection coaxial method in the first part of this thesis. The coaxial probe was modeled as an antenna and a calibration procedure with four standards was used. The complex permittivities and permeabilities of epoxy samples were determined using reflection and transmission data from a measurement using a filled rectangular waveguide in the second part of the thesis. This determination was based on data from measurements, simulations and mathematical calculations and evaluated with the Nicolson-Ross-Weir algorithm. Some Comsol Multiphysics models and data from partially filled waveguides are also presented."

2012-09-07 Ex-jobbspresentation: "Joint Topology and Routing Optimization Problem in Wireless Optical Networks"

Publicerad: 2012-08-31

Master thesis title: Joint Topology and Routing Optimization Problem in Wireless Optical Networks
Student: Itong Wijoko
Examiner: Ulf Koerner
Supervisor: Michal Pioro
Opponent: Asfandyar Khattak

Date: 7th September 2012 (Friday)
Time: 11.15
Venue: 2349 E-hus, LTH

Welcome!
Michal Pioro

Abstract
Optical Fiber (OF) is a common solution to build optical links in Metropolitan Area Networks (MAN) backbones. Such fiber links can be leased from an optical transmission carrier by a MAN operator. Free Space Optics (FSO) can potentially decrease the MAN operating cost by substituting (partly or fully) the OF links by the FSO links. Although using only FSO links can be substantially cheaper, using FSO links has also a number of drawbacks since an FSO link requires two sites that are in the line of sight, is limited in distance, and affected by weather conditions. These factors make FSO links not as reliable as OF links, and thus general FSO networking is more expensive than OF networking as the network topology of the former must be at least two-connected.
Therefore, identifying a subset of OF links that should be substituted by a set of FSO links, placement of the links, and identifying the demand routing, in order to minimize the total cost of the network is an optimization problem that is called Joint Topology and Routing Optimization Problem (JTROP). In the thesis an optimization for JTROP is developed, implemented and run on a set of network examples. The numerical results show that JTROP is capable of improving the pure FSO link solution when two-connectivity of a network is assumed.

Keywords: OF, FSO, LOS, topology, optimization, disjoint-path, two-connectivity.

2012-09-07 Ex-jobbspresentation: "Event based control of server systems"

Publicerad: 2012-09-04

On Friday 7/9 at 10.15 in E:3139, Elisabeth Jeppsson Krell and Jennie Ohlsson will present their master thesis titled "Event based control of server systems".
This project has been jointly supervised at EIT and Dept. of Automatic Control within the Lund Center for Control of Complex Engineering Systems (LCCC).

You are all welcome to attend,
Maria Kihl and Anton Cervin

Abstract
This thesis was performed and supervised as a collaboration between the Department of Automatic Control and the Department of Electrical and Information Technology at Lund University. The thesis investigates the possibility of utilizing event based control on a server system, modelling a cloud computing system. The model consists of an extended M/M/1 system with time-varying arrival and processing rates. Two estimation methods were developed and used in a prediction algorithm which in turn was used in the derived control law. The system was implemented and simulated in both MATLAB and in Java including the developed algorithms. From simulations suitable parameter settings were produced for the di erent algorithms. The derived control design was compared to an uncontrolled system and the results state that the developed controller improved the performance of the system, concluding that it is possible to use event based control on a server system.

2012-09-07 Ex-jobbspresentation: “Design, Simulations and Measurement Of UWB Antennas for Wireless Body Area Network”

Publicerad: 2012-09-06

On Friday 7th September at 14:15 in E:2311, Aida Garcia Lopez and Ernesto Lopez Canelon will present their master thesis titled: “Design, Simulations and Measurement Of UWB Antennas for Wireless Body Area Network”
The work was performed at EIT department and has been supervised by Rohit Chandra with Anders J Johansson as examiner. The abstract is as follows:

Welcome!
Rohit Chandra

Abstract
Wireless Body Area Network (WBAN) is an emerging technology in the field of health monitoring. It consists of miniaturized sensors either wearable or implantable which communicate through a wireless link with each other or to a central device. Since these devices are placed on the body, they have to be ultra-low power. In some applications high data rate is also desirable. With the Ultra-Wideband (UWB) technology these requirements could be achieved. The antenna plays a vital role in these wireless devices. In this project two three-dimensional UWB antennas have been designed: a volcano antenna and a diabolo shaped antenna. The design and the simulations have been done on a commercial 3D electromagnetic solver, SEMCAD-X, which uses the FDTD method. Since the antenna will be placed on the body, the simulations have been done taking the consideration of the human body. A realistic numerical human phantom has been used for this purpose. These antennas are matched within the UWB range (3.1-10.6 GHz), with the S11 parameter below -10 dB. The volcano antenna (45x45x27 mm) has a bandwidth ratio of 3.9:1, and the diabolo shaped (17x17x15 mm) has a bandwidth ratio of 6.2:1. Both have omnidirectional radiation pattern for on-body communication. In addition, these antennas have perpendicular polarization with respect to the body surface, required for low loss of creeping waves, propagating over the body surface. The antennas were manufactured by 3D printing technology using steel, and then covered with copper tape to increase the conductivity and soldering ability to the connector. The measurement has been done with a Vector Network Analyzer for S11, and the antennas were found to be matched in the UWB band. The path-gain (S21 parameter) between the volcano and diabolo antenna at 20 cm was measured with the VNA, resulting in an average path-gain of -34 dB for co-polarization and -52 dB for cross-polarization, verifying the linear polarization of the antennas. This thesis confirms the hypothesis made by John D. Kraus of the volcano antenna and shows an alternative method of manufacturing antennas by 3D printing.

Disputation Dzevdan Kapetanovic

Publicerad: 2012-06-09

Datum: 2012-09-04, kl 10:15
Plats: Lecture hall E:1406, E-building, Ole Römers väg 3, Lund University Faculty of Engineering
Opponent: Professor Erik Agrell. Chalmers University of Technology, Göteborg, Sweden
D. Kapetanovic:
On Linear Transmission Systems
ISSN 1654-790X, 2012.
Abstract: This thesis is divided into two parts. Part I analyzes the information rate of single antenna, single carrier linear modulation systems. The information rate of a system is the maximum number of bits that can be transmitted during a channel usage, and is achieved by Gaussian symbols. It depends on the underlying pulse shape in a linear modulated signal and also the signaling rate, the rate at which the Gaussian symbols are transmitted. The object in Part I is to study the impact of both the signaling rate and the pulse shape on the information rate.

Part II of the thesis is devoted to multiple antenna systems (MIMO), and more specifically to linear precoders for MIMO channels. Linear precoding is a practical scheme for improving the performance of a MIMO system, and has been studied intensively during the last four decades. In practical applications, the symbols to be transmitted are taken from a discrete alphabet, such as quadrature amplitude modulation (QAM), and it is of interest to find the optimal linear precoder for a certain performance measure of the MIMO channel. The design problem depends on the particular performance measure and the receiver structure. The main difficulty in finding the optimal precoders is the discrete nature of the problem, and mostly suboptimal solutions are proposed. The problem has been well investigated when linear receivers are employed, for which optimal precoders were found for many different performance measures. However, in the case of the optimal maximum likelihood (ML) receiver, only suboptimal constructions have been possible so far. Part II starts by proposing new novel, low complexity, suboptimal precoders, which provide a low bit error rate (BER) at the receiver. Later, an iterative optimization method is developed, which produces precoders improving upon the best known ones in the literature. The resulting precoders turn out to exhibit a certain structure, which is then analyzed and proved to be optimal for large alphabets.

2012-08-31 Ex-jobbspresentation: "Design and Evaluation of MIMO Terminal Antennas with Adaptive Matching .........."

Publicerad: 2012-08-24

On Fri, 31 August 2012 at 13.15 (in E:2311), Ehsan Foroozanfard will present his Master Thesis on the topic "Design and Evaluation of MIMO Terminal Antennas with Adaptive Matching in Realistic Environments".

You are all most welcome!
Buon Kiong Lau

Abstract
The Long Term Evolution (LTE) standard for wireless communication devices requires the use of multiple-input multiple-output (MIMO) technology in user terminals. However, since mobile phones are small in size, the design of multi-antennas is challenging. Moreover, the influence of user proximity and propagation environment must also be considered in the design. In addition, due to the non-stationary nature of the user and propagation channel, the multi-antennas must adapt to changes in order to achieve optimal performance.
The major aim of the thesis project is to evaluate and compare the performance of three multi-antenna prototypes equipped with adaptive impedance matching networks. We estimate the capacity gain from employing this adaptive method in realistic environments that include user effects. The latter has been achieved with a homogenous hand model whose posture can be conveniently manipulated to emulate different hand grips.
The first phase of the project involved the design of three different dual-band, dual-antenna prototypes for LTE bands 7 and 13. The antenna elements used in the prototypes are planar inverted-F antennas (PIFAs) and slot-monopole antennas. In the second phase, the prototypes were evaluated at the low frequency band in four user scenarios which are: one hand (data mode, talk mode), two hands and free space. Finally, capacity gains from applying adaptive impedance matching were calculated and analysed for the low band.
The results show that the first prototype offers the highest capacity improvement at the center frequency (i.e., 27%), obtained for the talk mode scenario. In addition, the mean capacity is improved by 22% over the band of interest.

2012-08-31 Ex-jobbspresentation: "Nonlinear Pre-distortion using Convex Optimization"

Publicerad: 2012-08-28

Yezi Huang will present her Master Thesis entitled "Nonlinear Pre-distortion using Convex Optimization" on Friday 31/8 at 11:15 in E:3139.

Welcome!
Thomas Magesacher

Abstract:
Orthogonal frequency division multiplexing (OFDM) is a widely used modulation scheme in today’s and emerging communication systems. Its inherently high peak-to-average-ratio (PAR) as well as high out-of-band spectral emissions (OBE) are two main drawbacks of OFDM. Active constellation extension (ACE) is a clipping-based, nonlinear pre-distortion method to reduce PAR. It makes use of the outer space on the constellation map without reducing the minimum distance of the constellation and thus maintains the bit-error-rate (BER) performance. The originally proposed ACE method is sub-optimal and does not consider OBE. In this thesis, an optimal ACE method – optimal in the sense of minimizing PAR while maintaining an OBE constraint – is proposed. Instead of explicitly clipping the peaks, the convexity of the ACE constraints and peak constraints is exploited. The optimally pre-distorted signal is found by searching for the minimum distance between convex sets.

2012-08-31 Ex-jobbspresentation: "Low Peak-to-Average-Power-Ratio Filter Design"

Publicerad: 2012-08-28

Mahmoud Alizadeh will present his Master Thesis entitled "Low Peak-to-Average-Power-Ratio Filter Design" on Friday 31/8 at 13:15 in E:3139.

Welcome!
Thomas Magesacher

Abstract:
The peak-to-average power ratio (PAPR) is an important parameter in modern communications systems in general and multi-carrier modulation systems in particular. A vast amount of methods to reduce the PAPR has been proposed. Linear filtering, which is often a part of the transmit-processing chain, causes the PAPR to re-grow. This thesis investigates ways to design peak-aware filters using the filter’s l1-norm as metric. Three different methods are investigated. The first one is based on spectral factorization of a given magnitude response. The second method is a least-squares design and the third approach is an equi-ripple design. The latter two are cast as convex problems and trade magnitude-specification violations against PAPR performance.

2012-08-28 Ex-jobbspresentation: "Facebook traffic data and cacheability"

Publicerad: 2012-08-23

Francesc Soler and Sergi Ibern will present their master thesis "Facebook traffic data and cacheability" on Tuesday 28/8 at 10.15 in E:3139.
The master project has been performed within the CelticPlus project IPNQSIS, in cooperation with Acreo AB and Ericsson Research.

You are all welcome!
Maria Kihl

Abstract
Nowadays, saving bandwidth means saving money. Because of that, ISPs and network operators are interested in giving the best service possible to their customers taking advantage of an efficient use of the network and its bandwidth. Due to Facebook is one of the most important social networks and it is also one of the most visited web pages, ISPs and network operators are interested on how it works. The main goal is to study how Facebook works, to study FB user behavior and to cache content locally in order to save bandwidth. The knowledge of FB is really useful because if we can identify which kinds of contents are more popular, it would be possible to predict potential cacheable content. For instance, if there is a FB user who every time posts a picture and then a lot of other users download his content, it would be interesting to cache it locally. In this thesis there are some studies in order to know how Facebook works. First of all we have analyzed Facebook data traffic with Wireshark (only local traffic). It has been useful to create some filtering rules which let us to filter each part in Facebook like Pictures, Update Status, Likes, Chat or Videos. After that, we did a 7 days packet dump from a real network using PacketLogic. The last step was creating some Python scripts in order to make statistics with all data. From the thesis study, it has been found some really interesting results and conclusions about two parts of Facebook: Downloaded Pictures and Likes.

2012-08-17 Ex-jobbspresentation: “Self-aligned Ni-GaSb alloy S/D GaSb PMOSFET”

Publicerad: 2012-08-14

On Friday 17 August at 11.15 in E:2311, Cezar Zota will present his master thesis, entitled “Self-aligned Ni-GaSb alloy S/D GaSb PMOSFET”. The work has been performed at the University of Tokyo under the supervision of Professor Shinichi Takagi.

Everyone is welcome to attend!
Erik Lind

Abstract:
In the first part of this work, I show that Ni reacts with GaSb under certain annealing conditions to form a Ni-GaSb alloy, which is a suitable metal for the source, and drain of metal source and drain GaSb p-channel oxide semiconductor field-effect transistors (PMOSFETs). The Ni-GaSb/GaSb contact has a large electron Schottky barrier height (SBH), ~0.5 eV, and low hole SBH, ~0.2 eV, which is beneficial for the realization of high on/off-current ratio in PMOSFETs. The Ni-GaSb alloy has a low sheet resistance of 7 ohm/□ and a low resistivity of 1.47 × 10-5 ohmcm. Ni can also be etched selectively against the Ni-GaSb alloys, which allows us the use of a self-aligned source/drain formation process. In the second part, I fabricate self-aligned metal S/D PMOSFETs using the Ni-GaSb alloy and show that they are functional.

2012-08-17 Ex-jobbspresentation: "Evaluation of WCDMA equalizers"

Publicerad: 2012-08-15

On Friday 17 August at 15.15 in E:3139, Dinil Koshy Mathews will present his master thesis "Evaluation of WCDMA equalizers". It has been conducted at ST-Ericsson.

Welcome!
Fredrik Rusek

Abstract
In Wideband Code Division Multiple Access (WCDMA), RAKE receivers are used to capture the signals approaching with different delays from different paths. The wider bandwidth in WCDMA provides improved multipath resolution but at cost of higher frequency selectivity (i.e. higher intersymbol interference). The different users in a cell are differentiated by using orthogonal codes. In a highly dispersive environment, the codes no longer remain fully orthogonal. Hence this results in interference. In order to improve interference suppression G-RAKE receivers are used. This includes a RAKE plus a combiner (RACOM). The despreaded signals from each finger of RAKE are combined using weights such that the interference is minimized while maximizing signal power. In this thesis, theoretical derivation for Maximum Likelihood (ML), Minimum Mean Squared Error (MMSE) are studied for SISO system and then extended for MIMO system. The latter part of thesis involves benchmarking a couple of different practical equalizers to identify potential areas of improvement compared to ideal equalizer. The ideal equalizer is designed with perfect knowledge of propagation channel. The current practical equalizer is evaluated mainly at three points, the number of fingers required, loss in equalizer performance due to fixed point implementation of receiver algorithms and the gap in performance between genie and practical equalizer implementation. The equalizer performance was benchmarked based on the following parameters – throughput achieved in various environments, the SNR at receiver after the RAKE receiver and the Block Error Rate (BLER). From the thesis study, it was found out how the different practical equalizers perform when compared to each other and to genie, proposals were made as to the number of fingers to be used and on how to improve the throughput of practical equalizer. The thesis points out the limitation of the evaluated practical equalizers in a MIMO system. The thesis also describes the loss due to float to fixed point conversion and the performance gap between genie and practical equalizers.

2012-06-28 Ex-jobbspresentation: “Channel Measurements and Analysis for Very"

Publicerad: 2012-06-25

On Thursday 28/6 at 15.15 in E:2311, Sohail Payami will present his master’s thesis “Channel Measurements and Analysis for Very Large Array Systems At 2.6 GHz”. You are all welcome to attend. Also, if you have any opponents they are welcome to contact me.

Fredrik Tufvesson

Abstract
This thesis considers the eects of using physically large array multiple-input and multiple-output systems also known as massive MIMO. These systems can offer significant performance improvements in multi-user scenarios where there is a base station with a large number of antennas and users are equipped with a single an- tenna. By implementing a virtual linear array, a measurement based approach is followed in this work. The base station is equipped with 128 antennas and 26 line-of-sight users and 10 non-line-of-sight can use the channel. We investigate the consequences of physically large array from both propagation and performance perspectives. While dealing with channel properties, we look into channel coherence bandwidth, K-factor, channel gain, distribution of eigenvalues and correlations at both uplink and downlink. We show that having an excess number of antennas can significantly improve channel decorrelation. Compared to conventional MIMO systems, it could be said that the statistical properties significantly vary over the array. From a system performance point of view, we show that the array gain significantly increases the channel capacity. Furthermore, by comparing the matched filter, zero-forcing and minimum mean square error pre-coding/ receiver schemes, large arrays can successfully improve the signal-to-interference-noise- ratio (SINR). When having large number of antennas at the base station, all the three methods show a very good performance which tends to be optimal.

2012-06-29 Ex-jobbspresentation: “Sine Function Approximation using Parabolic Synthesis and Linear Interpolation”

Publicerad: 2012-06-25

On Friday June 29 at 13.15 in E:2349 Madhubabu Nimmagadda and Surendra Reddy Utukuru will present their master’s thesis:
“Sine Function Approximation using Parabolic Synthesis and Linear Interpolation”

You are all Welcome!
Peter Nilsson

Abstract
This Thesis work deals with the ASIC implementation of sine function approximation using the combination of Parabolic Synthesis methodology and linear interpolation. Parabolic Synthesis is a novel methodology for implementing unary functions such as logarithmic, trigonometric, and arithmetic functions. This methodology gives a high degree of parallelism and efficient use of hardware compared to existing algorithms like polynomial approximation, CORDIC etc. Parabolic Synthesis is combined with linear interpolation in order to achieve the high accuracy. The architecture is designed to achieve maximum speed, less area and efficient power consumption. Keywords: Parabolic Synthesis, Linear interpolation, MCM, Sine function

2012-06-28 Ex-jobbspresentation: “Camera configuration using the audio ports and a Smartphone”

Publicerad: 2012-06-26

On Thursday June 28, 9.15 Olle Landin and Johannes Jakobsson will present their master’s thesis “Camera configuration using the audio ports and a Smartphone” in E:2311.
You are all welcome to attend.
Fredrik Tufvesson

Abstract
A common interface among a wide range of hardware devices is audio in- put/output. Axis Communications AB have identified the possibility to im- plement a communication protocol making it possible to send data between the audio ports of a smartphone and an Axis device. It is desired to be able to send image and video from an Axis device to a smartphone. This sets the highest requirement on the transmission rate of the protocol. Audio-based communication has been achieved by the implementation of a simple protocol, working at four of the levels in the OSI-model: the physical layer, the data-link layer, the session layer and the application layer. The session and application layers handles the dialog control and what type of requests that are possible to send, and what to send as a response to a specific request. A request is then put into a frame in the data-link layer. The frame consists of a header with a data-length field and a checksum followed by the request data. At the physical layer, the frame is then modulated into an array of samples using Pulse Amplitude Modulation. All samples are then sent to the sound driver, which plays the signal as audio. At the receiving end, the Catmull-Rom spline algorithm has been used to better reconstruct the signal during demodulation. Performance for different configurations of the protocol is measured by looking at the bit rate and error-ratio for every configuration. The impact of characteristics such as the symbol frequency, the number of PAM levels and the use of signal reconstruction have been examined. The bit rate of 1180 byte/s is sufficient to send an image over the channel, but not to send video with a pleasant frame rate. There are still possibilities to improve the protocol, trying different pulses, other modulation techniques such as QAM and sending compressed video instead of a series of JPEG-images.

2012-06-19 Ex-jobbspresentation: "Hardware Acceleration for Robust Header Compression (RoHC) Algorithm"

Publicerad: 2012-06-18

On Tuesday June 19 @ 10.15 in E:3139, Mohammed Al-Obaidi and Harshavardhan Kittur will present their Master’s Thesis:
"Hardware Acceleration for Robust Header Compression (RoHC) Algorithm",
done in cooperation with Ericsson in Linköping.

Welcome,
Viktor Öwall

Abstract:
With the proliferation of 4G/LTE networks, many cellular carriers are embracing the emerging field of mobile Voice over Internet Protocol (VoIP). Robust header compression (RoHC) framework was introduced as a part of LTE Layer 2 stack to compress the large headers of VoIP packets which are encapsulated RTP/UDP/IP stack compared to the small payload, and transmitted over 4G/LTE IP-based architecture. This header- compression scheme is especially useful for efficient utilization of the radio bandwidth and network resources. In LTE base-station implementation, RoHC is a processing intensive algorithm that may prevent the LTE system from catering to a full capacity (number of users). In this thesis, A hardware-software and a full-hardware solutions are proposed targeting LTE base-stations to accelerate this computational intensive algorithm and enhance the throughput and the capacity of the system. The results of both solutions are discussed and compared with respect to the design metrics like throughput, capacity, power con- sumption, area and flexibility. This comparison is instrumental in taking architectural level trade-off decisions in-order to meet the present day requirements and yet be ready to support future evolution. In HW-SW solution , 6250 packets/Sec can be processed at a frequency of 150 MHz by implementing the CRC and LSB encoding components in hardware. Whereas in Full-HW solution, a throughput of 243k packets/Sec is achieved at a frequency of 90 MHz. However, the Full-HW solution consumes more Look-Up Tables (LUTs) when it is synthesized on an FPGA platform compared to the HW-SW solution. In Arria II GX, the Full-HW and the HW-SW solutions use 7477 LUTs and 2578 and consume 0.9 Watts and 1.5 watts respectively. Finally, both solutions are synthesized and verified on Altera’s Arria II GX FPGA.

2012-06-14 Seminarium: ”III-V Compound Semiconductor Devices for Millimeter-Wave and THz Applications”

Publicerad: 2012-06-11

On Thursday Prof. Patrick Fay from University of Notre Dame will give a seminar at EIT entitled ”III-V Compound Semiconductor Devices for Millimeter-Wave and THz Applications”. You find the abstract below. The seminar will be at 11.15 in E:2311. Inspired by the Notre Dame visitor tradition (that I appreciate a lot), I also arrange a discussion schedule for his visit here in Lund (Tuesday-Thursday). Please let me know if you have an interest for a personal discussion and I will make sure you will be on the schedule.

Best regards,
Lars-Erik Wernersson

Abstract:
Between advances in scaling conventional III-V devices and exploration of novel device concepts, significant improvement in performance for emerging applications in the millimeter-wave through THz frequency range has been demonstrated. In this talk, several device technologies being pursued at the University of Notre Dame will be described. In terms of conventional device scaling, recent advances in scaled GaN-based HEMTs will be presented; an experimentally-demonstrated ft of 370 GHz shows that GaN-based devices are not only attractive for microwave power amplification, but also for millimeter-wave circuit applications. In the area of sensing, the use of InAs/AlSb/GaSb heterostructure backward diodes for millimeter-wave and THz detection and imaging is being explored. These devices offer extremely low noise performance, have demonstrated record sensitivity performance, and can be integrated monolithically with antennas for focal plane array applications. An overview of this device technology as well as opportunities and challenges will be presented. Finally, novel device concepts that are being explored for THz applications, such as GaN-channel RTD-gated plasma-wave HEMTs, will be discussed. Bio: Patrick Fay is currently a professor in the Department of Electrical Engineering at the University of Notre Dame, Notre Dame, Indiana, USA. He received a Ph.D. in electrical engineering from the University of Illinois at Urbana-Champaign in 1996 after receiving a B.S. in electrical engineering from Notre Dame in 1991. Dr. Fay served as a visiting assistant professor in the Department of Electrical and Computer Engineering at the University of Illinois at Urbana-Champaign in 1996 and 1997, and joined the faculty at the University of Notre Dame in 1997. His research interests include the design, fabrication, and characterization of microwave and millimeter-wave electronic devices and circuits, as well as high-speed optoelectronic devices and optoelectronic integrated circuits for fiber optic telecommunications. His research also includes the development and use of micromachining techniques for the fabrication of microwave components and packaging. His educational initiatives include the development of an advanced undergraduate laboratory course in microwave circuit design and characterization, and graduate courses in optoelectronic devices and electronic device characterization. He was awarded the Department of Electrical Engineering’s IEEE Outstanding Teacher Award in 1998-1999. Prof. Fay is a senior member of the IEEE, and has published 8 book chapters and more than 90 articles in refereed scientific journals.

2012-06-13 Disputation: Mats Ärlelid

Publicerad: 2012-05-28

Disputation Mats Ärlelid

Datum: 2012-06-13, kl. 10:15

Plats: E:1406, E-huset, Ole Römers väg 3, Lunds Tekniska Högskola

Opponent: Professor Patrick Fay, University of Notre Dame, IN, U.S.A.

https://lup.lub.lu.se/luur/download?func=downloadFile&recordOId=2540282&fileOId=2540288

Abstract: This thesis investigates the opportunity of wireless multi-gigabit per second communication at the millimeter-wave (mmW) frequencies around 60 GHz by using impulse radio and nanoelectronics. Today most wireless communication take place in the microwave region, where several different systems and applications are crowding the narrow-band channels. Complicated schemes are applied in order to avoid interference and still provide good performance in terms of bit rate. Many regulatory associations have allocated a wide unlicensed frequency band around 60 GHz, which may offer the possibility to build short-range wireless systems that provide high throughput. Wireless high definition multimedia interface (HDMI) and fast synchronization of mobile devices are some of the intended applications. Furthermore, remote sensing applications such as radar, imaging and localization may be considered due to the wide bandwidth, which may offer high resolution. The impulse radio front-ends that are presented in this thesis are monolithic microwave integrated circuit (MMIC) designs in compound semiconductor materials, such as GaAs and InGaAs, compounds built from groups III-V of the periodic system. By choosing such compound materials, it is possible to design devices with high performance such as III-V metal-oxide-semiconductor field-effect transistors (MOSFETs) with mmW cut-off frequency and high transconductance. Moreover, it is possible to utilize bandgap-engineered devices with unique properties such as resonant tunneling. The presented transmitters incorporate resonant tunnel diodes (RTDs) that provide negative differential conductance, and may be used to generate substantial amount of mmW signal power by integrating the device in a resonance circuit, an oscillator. Furthermore, the addition of a third gating terminal to the RTD will present control over both the magnitude and the sign of the differential conductance. By switching the differential conductance of the RTD device between positive and negative magnitudes in a resonance circuit, it is possible to turn the oscillator on and off to generate wavelets, short pulses of radio frequency oscillation. This design offers sub-period start-up time, which is due to the kick-start action of the oscillator. Also, rapid decay is provided since the RTD device actively helps to quench the oscillations when set to positive differential conductance. The best wavelet generator operation was achieved with a MOSFET/RTD combination, where 41 ps long wavelets were generated with 7 dBm peak output power up to a rate of 15 GHz. The wavelet generator was used to investigate the properties of mmW impulse radio and studies show the possibility to obtain 4 Gbps links over short distances using low-level modulation on-off keying. The wavelet generator may also be used as a super-regenerative oscillator by modifying the control signal. Instead of switching the RTD device rapidly into negative differential conductance, it is tuned slowly. Through this action the oscillation may be started from noise or received signal energy. A 400 Msamples/s super-regenerative oscillator is presented, which may be an interesting candidate for implementation in a low-power mmW impulse radio receiver.

2012-06-05 Ex-jobbspresentation: “Analog Adaptive Equalizer for a Clock-Less System“

Publicerad: 2012-06-01

Vinoth Kannan Ilamurugan will present his master thesis on Tuesday 5th of June @13:15 in E:2311
The thesis work has been performed at NXP semiconductors, Eindhoven, Netherlands.
The title is “Analog Adaptive Equalizer for a Clock-Less System“

Welcome
Markus Törmänen

Abstract:
This thesis implements a slope detection based analog adaptive equalizer in 140nm CMOS technology for a USB 3.0 redriver application. This thesis is performed in the Mixed Signals Solutions group at NXP semiconductors, Eindhoven, The Netherlands. Due to the scaling of IC technology, the speed and performance of integrated circuits is continuously increasing. Designing a chip operating at Multi-Gbps becomes a feasible solution. However, the bandwidth of the interconnect scales at a much lower rate compared to the on-chip bandwidth, thus making the communication link between chips the major bottleneck for the overall system performance. Signal crosstalk between the adjacent lines becomes more significant, when transferring large volume of high-speed data over a parallel transmission lines. So the high speed communication interfaces are moving from parallel data transmission to serial data transmission to reduce the crosstalk issues. Serial interfaces also have the advantage of lower pin counts, thinner cables and smaller connectors leading to significant cost reduction. USB 3.0 is a serial interface standard that specifies a maximum transmission speed of upto 5Gbps in each direction, which is ten times faster than USB 2.0 (480Mbits/s). The main drawback at this high speed data transmission is the loss of signal integrity over longer cable lengths or PCB traces. Also, a USB 3.0 host or device can be connected to cables of different length. A Redriver IC plays a vital role in maintaining signal integrity over a lossy transmission line. The Redriver IC is analog in nature and does not perform clock and data recovery. The main purpose of the redriver IC is to restore the signal quality of a deteriorated input signal. Equalizer is one of the key component inside the redriver IC. Implementing an equalizer with fixed gain setting will result in non-optimum ISI at receiver input. Therefore, an adaptive equalizer to automatically detect and compensate the channel loss is preferred. This thesis focuses on implementing a slope detection based analog adaptive equalizer for such a redriver application. Analog implementation of adaptive equalizer has the advantage of lower power consumption compared to digital implementation. The implemented slope detector architecture does not perform the clock recovery. The adaptive equalizer is modeled in Verilog-A, along with the characteristics of microstrip channel, USB 3m cable and the adaptive loop operation and convergence behavior are simulated. The transistor level implementation of adaptive block and limiting amplifier consumes 11.7mW of power from a 1.8V supply. The performance of the adaptive block is simulated with difference process corners and it shows excellent results.

2012-06-04 Seminarium: Professor Margaret Cheney

Publicerad: 2012-05-30

On Monday, June 4, 2012, professor Margaret Cheney , Rensselaer Polytechnic Institute, Troy, USA, makes a short visit at EIT.
Professor Cheney is one of the world’s leading experts on imaging using synthetic aperture radar (SAR), and she was LTH’s first Lise Meitner professor at the former Department of Electroscience in 2000.
On Monday June 4 at 10.15 she gives an informal seminar entitled “Radar Imaging” in E:3139.

Welcome

Gerhard Kristensson

2012-06-01 Ex-jobbspresentation: “Optimization of High-k films on Si Substrate"

Publicerad: 2012-05-31

This coming Friday,1st of June, Aein will present her diploma project at 11:15 .You are welcome to attend the presentation! Since the Thesis is made at the Natural Science Faculty it will be presented in room H422 at the physics department.
The title is “Optimization of High-k films on Si Substrate".Please, find the abstract below.

Welcome
Lars-Erik Wernersson

Abstract:
Using high-k materials such as hafnium oxide and Aluminum oxide enables fabrication of field effect transistors with promising device performances, but there are still shortcomings that need to be improved. One of the challenges to fabricate high quality devices is to improve the interfacial layer of the gate oxides with the semiconductor substrate. Defects and imperfections at the interface of high-k films on silicon and III-V semiconductors as well as charge trapping within the oxide layer affect capacitance-voltage characteristics of devices. One approach to optimize the device performance is to improve the oxide-semiconductor interface. This work focuses on fabrication and characterization of metal oxide semiconductor capacitors with atomic-layer-deposited HFO2 and Al2O3. The oxides were grown with different ALD conditions, like different precursor pulse lengths and deposition temperatures. The effect of growth conditions on current-voltage (I-V) and capacitance-voltage (C-V) characteristics of the MOS structures was investigated in order to find an optimized condition with reduced frequency dispersion and hysteresis.

Disputation Fredrik Harrysson

Publicerad: 2012-05-04

Datum: 2012-05-29, kl 13:15
Plats: Lecture hall E:1406, E-building, Ole Römers väg 3, Lund University Faculty of Engineering
Opponent: Dr. Tim Brown. University of Surrey, U. K.
F. Harrysson:
Multiple Antenna Terminals in Realistic Environments - A Composite Channel Modeling Approach
Series of licentiate and doctoral theses, ISSN 1654-790X; No. 41, Lund University, 2012.
Abstract: For evaluation of specific antenna arrangements in wireless communication systems we need physical channel models that take into account also the directional domain of the propagation channel. In this thesis we investigate, validate and propose a practical approach to wireless channel modeling and, particularly, to mobile communication systems. For this we make the assumption that the channel can be divided into separate parts, or regions that can be treated and modeled separately. The basic idea is that the antenna parts of the channel is the parts considered in the design of base station antennas and user equipments and can be characterized by a single measurement of each design, while the propagation part of the channel can be characterized separately, independent of the specific installed base station antenna or the user equipment, but based on generic channel sounder measurements with, as far as possible, open areas around the transmitter and the receiver antennas. For more complex antenna environments we may imagine intermediate scattering regions of the channel model between the antenna parts and the propagation part, that can or cannot be handled separately, e.g., the body of a mobile phone user, an office desk, a vehicle, surroundings of base station antennas in dense deployments, etc. A first step in evaluating such a composite channel modeling approach is to verify the validity of communication link simulations were the mobile phone antennas together with the user can be treated as a super-antenna with its aggregate far-field pattern to be combined with a directional channel model in a classical way. This is first presented in Paper II, and the method is in its extensible form here referred to as a composite channel method. It is found that this method, as we expected, work well for statistical performance evaluation of diversity and spatial multiplexing. An extension of the composite approach is outlined with an attempt to find a simple yet accurate directional scattering model for, firstly, the user body, and, secondly, a car environment with the user inside. A simple model that still catch the proper influence of antenna efficiency, fading statistics, and correlation at the mobile side. In Paper I a first investigation of user influence on an indoor 2x2 multiple-input multiple-output (MIMO) link is performed based on a narrowband measurement setup and the diversity performance is evaluated. In Paper II, the first step of the composite channel approach is evaluated with respect to MIMO by channel measurements including user influence in two static outdoor-to-indoor and indoor-to-indoor scenarios. The approach is verified for statistical properties such as antenna correlation and MIMO eigenvalue distributions. It is found, with extended detail given in Paper III that the presence of the user, apart from introducing hand and body absorption and mismatch that increases the path loss, also increases the correlation between the antenna branch signals and, thus, slightly decreases potential MIMO capacity. In Paper IV and Paper V the investigation is extended to the scenario were the user is located inside a family car (station wagon). In Paper IV a first analysis of an outdoor MIMO measurements campaign with the user outside and inside the car is presented. The results show an increased scattering inside the car that improves mainly the potential diversity gain, and to some extent also the potential MIMO capacity gain, to the cost of higher path loss (lower SNR) due to car penetration loss. An important observation is the dependency of this penetration loss on the directional properties of the outer propagation channel, which indicates a possible need for scenario dependent penetration loss in general channel modeling. In Paper V this is further verified with directional estimation of the propagation channel both outside and inside the car. We also find that the composite channel method with the inherit assumption of plane-waves impinging on the mobile terminal, actually does produce good results even in this close near-field environment inside the car with the nearby scatterers within the far-field (Rayleigh) distance of the probe antenna array.

2012-05-28 Ex-jobbspresentation: "OTA measurements and performance optimization of mobile terminals for user scenarios"

Publicerad: 2012-05-21

On Mon, 28 May 2012 at 15.15 (in E:2311), Bangguo Zhu and Zheng Zhang will present their Master Thesis on the topic " OTA measurements and performance optimization of mobile terminals for user scenarios", which was performed at Sony Mobile Communications AB in Lund.

Welcome!
Buon Kiong Lau

The abstract is as follows:
Nowadays, with the widespread adoption of the multiple-input and multiple-output (MIMO) technology, traditional over-the-air (OTA) tests that do not account for multipath fading are no longer adequate for characterizing the performance of a MIMO device. Moreover, the effects of spatial correlation among multiple antenna elements and the interaction between the antenna elements and the surroundings should also be considered in the OTA measurement of MIMO antenna systems. In this research, the two main goals are: (1) to study the emulations of wireless channel models for MIMO systems, and (2) to optimize the performance of mobile phones for practical applications. First of all, three types of OTA measurement methods proposed by 3GPP standards are studied, and their respective advantages and disadvantages are discussed. The three methods are the MultiPath Simulator (MPS), the two-stage method and the scattered field chamber (SFC) method. The focus is on throughput and block error rate (BLER) performance. Our theoretical and measurement studies reveal that MPS is flexible for emulating a variety of propagation conditions, whereas the two-stage method is most cost effective, since it can reuse existing SISO OTA anechoic chambers to measure antenna patterns, and require only two channel emulator outputs. On the other hand, the SFC method offers the most stable performance, due to the isotropic channel it emulates, and it is quite useful for evaluating MIMO devices targeted for indoor environments. Secondly, through total radiated power (TRP) measurements of conventional smart phones, we identify critical problems in TRP performance resulting from hand-grip induced power loss as well as power imbalance between left and right hand grips in a talk position. Several novel antenna design solutions are proposed to address these problems. Specifically, for the single-antenna case, we find that the power imbalance problem can be mitigated by designing the antenna element to be symmetrical about the longer side of the ground plane. In addition, an external matching network have been used to improve the antenna bandwidth. In order to reduce hand-grip induced power loss for the multi-antenna case, antenna selection can be used to reduce the power loss in the human body by around 6 dB and 2 dB at the low and high bands, respectively, comparing to existing designs. You are all most welcome! BR// Vince

2012-05-25 Jan Rabaey promoveras till hedersdoktor

Publicerad: 2012-01-25

Jan Rabaey blir promoverad till hedersdoktor den 25 maj efter sitt ovärderliga arbete för EIT.

MER:
Artikel om Jan Rabaey
Hedersdoktorer vid LTH, med EIT-anknytning
LTH hedersdoktorer
Jan Rabaeys hemsida

2012-05-25 Ex-jobbspresentation

Publicerad: 2012-05-21

On Friday Jianan Liu (wireless com) and Chuanhai Bai (system on chip) will present their master’s thesis “R9 WCDMA DL Decoder for DCH in Real Time DSP Environment”, that has been performed at Ericsson in Gothenburg. E:2349, Friday May 25 at 9.15 If you have any students that would like to be opponents, please let me know.

Welcome!
Fredrik Tufvesson

Abstract
First chapter will go through background of WCDMA and 3GPP standard; Then, according to 3GPP 25 series standard, every baseband algorithm module will be reviewed from view of encoding side at chapter two; Next, chapter three will deal with structure of non real time SW decoder, going through every algorithm module (modules include descrambling, despreading, demodulation, deinterleaving, deratematching, both viterbi decoding and turbo decoding, CRC checking, as well as lots of other sub-modules and supporting modules, etc.) which is employed by decoder to explain the principle and details on how they worked; Chapter four will give a clear sight on how to investigate the real-time requirements of decoding, how to implement the real time decoding in DSP environment as well. In chapter five, issue on improvement of real time performance, e.g. methods to save operation time, will be discussed. At the last part, chapter 6&7, the conclusion and future work will be included.

2012-05-24 Hedersdoktorsföreläsning av Jan Rabaey

Publicerad: 2012-05-08

The Wireless Revolution Continued: from Mobiles to Swarms

Tid: Torsdagen den 24 maj, 13.15
Plats: E-huset på LTH, hörsal E:A

Vi bjuder på snacks och förfriskningar efter föreläsningen.

Abstract:

It was a dinner conversation sometimes in the mid 1980s that truly kindled my fascination for wireless technology. On a visit to Berkeley, Sven-Olof Öhrvik, then head of Ericsson Radio Systems (ERA) research and Professor at Lund University, ventured that over the next decade cellphones would become both digital and so small in size that they could slip into your shirt pocket. At a time when analog cellphones were barely a niche market, this sounded almost as an excerpt of a Science Fiction novel. The rest is truly history.

Since that very moment addressing the questions on how to make wireless components ever smaller and energy-efficient, and what truly ubiquitous wireless connectivity would mean to the society-at-large, have been leading threads through most of my research activities. It has led us along some exciting paths – from InfoPads and sensor networks to information-technology systems in support of society (CITRIS).

Notwithstanding the amazing impact these technologies have already had, the story does not end here. The wireless revolution is still going strong – wireless devices will continue to become smaller and more ubiquitous, giving birth to “swarms” of sensory and actuator devices that will blur the separation between the physical/biological world and the cyberspace. The endless opportunities this paradigm offers, what is needed to make this happen, and what could prevent it from happening are the main topics of this presentation. Some of it may read as Science Fiction again.

Läs mer:

Han önskade sig en iPad för 20 år sedan
Jan Rabaeys hemsida

2012-05-24 Ex-jobbspresentation: "Designs for Low-correlation Co-located Antennas"

Publicerad: 2012-05-21

On Thu, 24 May 2012 at 10.15 (in E:2311), Russell Whiton and Farzanehsadat Firouzabadi will present their Master Thesis on the topic "Designs for Low-correlation Co-located Antennas", which was performed at Sony Mobile Communications AB in Lund.

You are all most welcome!
Buon Kiong Lau

The abstract is as follows:
Smartphones integrate a large number of wireless technologies into one handheld device. Designing antennas for these devices is more challenging than ever with an increasing number of technologies and frequency bands compacted into smaller and smaller packages. Many devices need four or more antennas to integrate all the technologies demanded of competitive products. Multiple-Input-Multiple-Output (MIMO) antenna systems have added a new level of complexity for antenna designers. To realize the gains MIMO offers, two of the phone’s antennas need to operate simultaneously on the same frequencies, and not only be isolated from the power transmitted by each other, but also be uncorrelated. The design choice of where along the top, bottom, or sides of the phone to place the antenna is an important one. Perhaps the biggest challenge is placing the two MIMO antennas such that they meet the isolation and correlation requirements. If the two could be placed adjacently at one end of the phone it would allow for maximum flexibility. Greater design flexibility is extremely important with real-estate on the circuit board becoming a critical limitation as more features are packed into smaller spaces. This project explores in detail two new proposals for co-locating the antennas at the bottom of a handset and compares the results to previous work. This report discusses advantages and disadvantages of each method along with an analysis of key performance parameters.

2012-05-24 Ex-jobbspresentation: "Dynamical modelling of MySQL Database server"

Publicerad: 2012-05-22

On 24/5 at 11.15 in E:3139, Shirish Khatri Chhetri will present his master thesis "Dynamical modelling of MySQL Database server"

All are welcome,
Maria Kihl

Abstract
This thesis basically consists of different experiments conducted at the Department of Electrical and Information Technology, Lund University, Sweden. Different experiments in this thesis mainly focus to determine and investigate the model that can describe accurate behavior of dynamic of MySQL database server when load is introduced to the database server and also when any of these different metrics such as relation size, relation storage engine type, number of external concurrent connections is changed. Also, this thesis provides discussion on detection of different load traffic such as low load traffic, high load traffic and overload traffic in this MySQL database server from the application server and how these load traffic are affected when we change any of these different metrics such as relation size, relation storage engine type, and number of external concurrent connections.

2012-05-24 Ex-jobbspresentation: "Property Management System"

Publicerad: 2012-05-22

On 24/5 at 10.15 in E:3139, Mostafa Ali will present his Bachelor thesis with title "Property Management System".

All are welcome,
Maria Kihl

Abstract
Syftet med detta examensarbete är att undersöka olika Property Management Systems (PMS) för hotell och motell sedan designa ett bättre system som underlättar administrationen för hotelledningen och arbetet för personalen. Jag har kontaktat över 20 olika hotell i Malmö och Hamburg. Av dessa lyckats intervjua elva, resterande vägrade att svara på mina frågor. Just nu jobbar jag för en liten hotellkedja, Entrée Hotels, i Tyskland och jag fått möjligheten att även intervjua deras hotell. Tack vare denna erfarenhet har jag fått bättre insyn i hur ett PMS fungerar och har nu börjat utveckla olika program för att optimera deras arbete. Under tiden har jag även undersökt flera program för att se brister på dagens system och sedan studerade jag ett av programmen närmare. Programmet heter Citadel desk och är utvecklad av Citadel Hotel Software GmbH i Tyskland. Jag undersökt koden, databasernas struktur och programmets uppbyggnad etc. I detta examensarbete beskrivs bl.a. PMS och datareplikering, senare analysen av ett PMS och till slut kommer förslagen till ett bättre system. Vi kommer även att titta närmare på ett exempel för att se hur ett PMS är uppbyggd.

Disputation Anders Bernland

Publicerad: 2012-04-27

Datum: 2012-05-23, kl 10:15
Plats: Lecture hall E:1406, E-building, John Ericssons väg 4, Lund University Faculty of Engineering
Opponent: Professor Johannes Skaar. Norwegian University of Science and Technology (NTNU), Trondheim, Norway
A. Bernland:
Integral Identities for Passive Systems and Spherical Waves in Scattering and Antenna Problems
Series of licentiate and doctoral theses, Vol. 40, ISSN 1654-790X, Department of Electrical and Information Technology, Lund University, Lund, Sweden., 2012.
Abstract: Sum rules and physical limitations within electromagnetic theory and antenna theory have received significant attention in the last few years. However, the derivations are often relying on application specific and sometimes unsupported assumptions, and therefore a mathematically rigorous and generally applicable approach seems timely. Such an approach is presented in this thesis, along with examples and all the necessary proofs. The approach is also applied in the thesis to derive sum rules and physical limitations on electromagnetic spherical wave scattering. This has not been done before, despite the widespread use of spherical wave decompositions. For example, spherical waves and the antenna scattering matrix provide a complete and compact description of all the important properties of an antenna, are crucial parts in spherical near-field antenna measurements, and have been used recently to model antenna-channel interaction and multiple-input multiple-output (MIMO) communication systems. This thesis is also the first to present a method to estimate spherical wave coefficients from propagation channel measurements.

The results of this thesis can roughly be divided into three categories: Firstly, a general approach to derive sum rules and physical limitations on input-output systems based on the assumptions of causality and passivity is presented (Paper I). Secondly, sum rules and physical limitations on the scattering and matching of electromagnetic spherical waves are derived, and the implications for antennas are explored (Papers II-IV). Thirdly, a method to estimate spherical wave coefficients from channel measurements, and the results of a measurement campaign, are presented and analysed (Paper V).

The thesis consists of a General Introduction and five appended papers.

2012-05-22 Ex-jobbspresentation: "Energy Efficiency in Wireless Access Networks"

Publicerad: 2012-05-21

On Tue, 22 May 2012 at 10.15 (in E:2311), Zhi Chai will present his Master Thesis on the topic "Energy Efficiency in Wireless Access Networks", which was performed at Ericsson AB in Linköping.

You are all most welcome!
Buon Kiong Lau

The abstract is as follows:
The increasing concern about energy consumption of telecommunication networks is driving operators to manage their equipment so as to reduce energy consumption without sacrificing the quality of user experience. Radio base stations are the highest contributors to energy consumption and CO2 emissions in LTE mobile networks. In this paper, we apply an energy efficient (EE) algorithm to reduce the number of active radio units (RUs) when they are underutilized. The study involves both the energy saving potential and influence on user quality of experience (QoE) while the radio units are switched off. To investigate the performance of this EE algorithm the impact of several parameters are investigated, including FTP file sizes, traffic load, decision threshold level, sampling period and radio activation delay. It is shown, through experiments, the performance of the EE algorithm can be dramatically increased by setting a short sampling period and applying RUs with short activation delay. We can get considerable energy saving while the loss in user QoE is limited.

2012-05-22 Ex-jobbspresentation: "Radio Resource Management for M2M communication in LTE"

Publicerad: 2012-05-21

On Tue, 22 May 2012 at 11.15 (in E:2311), Wang Fu will present his Master Thesis on the topic "Radio Resource Management for M2M communication in LTE", which was performed at Ericsson AB in Linköping.

You are all most welcome!
Buon Kiong Lau

The abstract is as follows: The purpose of this study is to investigate the behaviors of different link adaptation designs with signaling reduction in random access procedure with small infrequent data transfers for M2M traffic in LTE. Signaling reduction with efficient radio resource management is an aggressive optimization for such small data transfers to be used to decrease the device energy consumption as well as to mitigate the high radio resource utilization issues. Simulations have been run to illustrate how different link adaptation designs affect the radio resource utilization as well as to illustrate the behavior for device energy consumption belonging to different models using discontinuous reception or not. Thirdly, the interaction between delay and device energy consumption is analyzed. Fourthly, the quality of the network service illustrated with the number of failure users is given. The results show that signaling reduction with efficient radio resource management could have potential good performance as long as the data transfers are small infrequent.

2012-05-22 Ex-jobbspresentation: ”Multiple Supply Voltages in Digital Baseband”

Publicerad: 2012-05-22

On Tuesday May 22 (tomorrow), 13:15-14:00, in E:2349, AZHER ALI MOHAMMED and MANIVANNAN ETHIRAJ will present their master’s thesis:
”Multiple Supply Voltages in Digital Baseband”

Welcome!
Peter Nilsson

Abstract
This thesis deals with low power research by using low voltages. The special interest is to implement multiple supply voltages using a single supply voltage, as the power consumption can be reduced by reducing the operating voltage. A diode connected NMOS transistor is used for voltage scaling. The robustness and feasibility of the diode connected NMOS as a voltage converter is tested and analyzed. As the operating frequency decreases the supply voltage required is decreased making this scenario ideal for the requirement of multiple supply voltages. A typical case of digital baseband filtering with decimation stages is used for testing. Multiple diode connected NMOS transistors are implemented for generating multiple supply voltages to be used in baseband filtering stages. An approximate power saving of 70 % is achieved from one stage to next stage by using this simple technique. The ultimate aim is to implement a simple circuit to provide multiple voltages for saving the power, whose power consumption itself is minimal.

2012-05-21 Ex-jobbspresentation: "Automated de-synchronization of synchronized clocked circuits"

Publicerad: 2012-05-16

I would like to invite you to the master thesis presentation of Andreas Karlsson on Monday 21st at 15:15 in E:3139.
Title: Automated de-synchronization of synchronized clocked circuits

Welcome!
Joachim Rodrigues

Abstract
In the pursuit of low power, low area and high speed chip design digital Application- Specific Integrated Circuit (ASIC) developers constantly pushes the boundaries of deep-submicron circuit design. The rapid advancement of decreasing the size of Complementary Metal Oxide Semiconductor (CMOS) technologies helps to push this process forward, but as technologies decrease in size their vulnerability to exte- rior disturbances increase. The documented robust properties of asynchronous circuits makes the synchronized → asynchronous step more and more compelling for synchronized circuits developers. But this step is not an easy one to take. The lack of Electronic Design Automation (EDA) tools and knowledge of asynchronous data flow inhibits the synchronous developer to see enough reason for this change of mind. In this project a de-synchronization flow was implemented using the Synop- sys Design Compiler (DC) compatible script language Tcl. The idea was to keep the synchronous design flow intact and only add a de-synchronization stage just after circuit synthesis. The implemented script is highly automated with only a header file in need of manual altering. On gate level it locates all synchronized compo- nents of a circuit, replaces them with locally controlled latches and applies a strict handshaking protocol to ensure error-less computation. The resulting circuit is an asynchronous circuit developed with a synchronous design flow with asynchronous properties such as local handshake control, distributed power peaks , variation ro- bustness, but on the downside, also increased power consumption and a large area overhead compared to its synchronized equivalent. This script gives the synchro- nized circuit developer a shortcut to asynchronous design. All gate level operation is done in Synopsys Design Vision.

Workshop: LCCC Linnaeus center

Publicerad: 2012-04-03

The LCCC Linnaeus center is arranging its 2nd industrial workshop on May 16, 2012.

The workshop will take place in M:B from 10:30 to 17:00 (with registration and coffee from 9:45). We are inviting industrial partners and research contacts that share the LCCC research vision on Control of Complex Engineering Systems to give talks. We are also arranging a poster session during the lunch break, where the LCCC researchers from Automatic Control and EIT will share their current research. The list of speakers so far includes

- Javier Ubillos (Spotify AB)
- Andreas Torstensson (Ericsson Karlskrona)
- Paul Haupt (GE Research)
- Hubertus Tummescheit (Modelon AB)
- Kilian Link (Siemens AG)
- Vladimir Havlena (Honeywell Prague)
- Martin Kjær (Vestas)

This will be an excellent opportunity to learn how systems and control theory can be used in real life and what the job market looks like.
The workshop will be free of charge (including lunch), but you need to SIGN UP NO LATER THAN MAY 7 at

http://www.lccc.lth.se/index.php?page=2nd-industrial-workshop

Welcome!

The workshop program committee,
Anton Cervin & Maria Kihl

Mer information

Ex-jobbspresentation: “Hardware Implementation of MIMO-OFDM channel estimation using Singular Value Decomposition technique”

Publicerad: 2012-05-10

On Wednesday May 16 at 13:15-14:00 in E:2349 Syed Zaki Uddin will present his Master’s thesis “Hardware Implementation of MIMO-OFDM channel estimation using Singular Value Decomposition technique”

Welcome!
Peter Nilsson

Abstract:
This Thesis presents modeling and hardware implementation of Robust Multiple Input Multiple Output (MIMO), Orthogonal Frequency Division Multiplexing (OFDM) channel estimator using Singular Value Decomposition technique for both frequency and time correlation of the channel.
High data rate communication is an emerging needs for future service protocols such as Long Term Evolution, Digital Video Broadcasting, IEEE 802.11, IEEE 802.16e (WiMAX) and many more exciting technologies to offer services on Mobile device. Restrictive regulations of spectral bandwidth for service providers limit transmission of high data rates under same bandwidth. Multiple Input Multiple Output systems are employed to offer high data rate transmission of data on same spectral bandwidth. These systems transmit data concurrently from all transmitting antennas and receive data concurrently on all receiver antennas. These systems suffer hugely from Inter Carrier Interference and Inter Symbol Interference due to overlapping of different transmitted antenna signals in the channel creating attenuated and not synchronized reception of data.
MIMO-OFDM is a promising technology for future mobile communication services to provide high data rate services under same spectral bandwidth along with reduced Inter symbol interference and Inter carrier interference, as data signals are orthogonal to each other in this protocol. Reception of error free message has always been desirable at receiver end, but ends up erroneous reception of data due to unforeseen Multi-path attenuation of channel. Channel Estimation is used to compensate these unseen channel effects creating it an interesting topic of research.
Channel Estimation has always been primary need at receiver end of Multiple Input Multiple Output-Orthogonal Frequency Division Multiplexing system to approximate original transmitted signals from noisy fading channels. This will reduce the error rate and provides error free data communication.
This work is a continuation work of Johan Löfgren (my supervisor), where Johan Löfgren (my supervisor) presented channel estimation technique by using only frequency correlation of the channel.

Disputation Florian Hug

Publicerad: 2012-04-19

Datum: 2012-05-16, kl 10:15
Plats: Lecture hall E:1406, E-building, Ole Römers väg 3, Lund University Faculty of Engineering
Opponent: Professor Emeritus Daniel J. Costello, Jr.. Department of Electrical Engineering, University of Notre Dame, USA
F. Hug:
Codes on Graphs and More
Series of licentiate and doctoral dissertations, ISSN 1654-790X No. 38, 2012.
Abstract: Modern communication systems strive to achieve reliable and efficient information transmission and storage with affordable complexity. Hence, efficient low-complexity channel codes providing low probabilities for erroneous receptions are needed. Interpreting codes as graphs and graphs as codes opens new perspectives for constructing such channel codes. Low-density parity-check (LDPC) codes are one of the most recent examples of codes defined on graphs, providing a better bit error probability than other block codes, given the same decoding complexity.

After an introduction to coding theory, different graphical representations for channel codes are reviewed. Based on ideas from graph theory, new algorithms are introduced to iteratively search for LDPC block codes with large girth and to determine their minimum distance. In particular, new LDPC block codes of different rates and with girth up to 24 are presented. Woven convolutional codes are introduced as a generalization of graph-based codes and an asymptotic bound on their free distance, namely, the Costello lower bound, is proven. Moreover, promising examples of woven convolutional codes are given, including a rate 5/20 code with overall constraint length 67 and free distance 120.

The remaining part of this dissertation focuses on basic properties of convolutional codes. First, a recurrent equation to determine a closed form expression of the exact decoding bit error probability for convolutional codes is presented. The obtained closed form expression is evaluated for various realizations of encoders, including rate 1/2 and 2/3 encoders, of as many as 16 states. Moreover, MacWilliams-type identities are revisited and a recursion for sequences of spectra of truncated as well as tailbitten convolutional codes and their duals is derived. Finally, the dissertation is concluded with exhaustive searches for convolutional codes of various rates with either optimum free distance or optimum distance profile, extending previously published results.

Ex-jobbspresentation: “Shielding Effectiveness in Nested Reverberation Chambers”

Publicerad: 2012-05-10

Tuesday 15 May 13.15 in E:2349
Andreas Johansson will present his master thesis “Shielding Effectiveness in Nested Reverberation Chambers”, which has been performed at SP Technical Research Institute of Sweden in Borås, under the supervision of Prof. Jan Carlsson, and me as examiner. The abstract is given below. If you have a student who wants to make an opposition, please let me know.

Welcome!
Daniel Sjöberg

2012-05-11: Paschalis seminar

Publicerad: 2012-04-05

Date:
Friday May 11th at 10.00 on E:3139

Title:
Recent Advances in Special Functions and Composite Statistical Distributions and Their Usefulness in Wireless Communications over Fading Channels.

Abstract:
It is widely known that fading affects information signals during wireless propagation. The past decade witnessed an enormous research activity in characterising fading adequately and then quantifying its effect on the performance of wireless communication systems. This is typically required to be performed mathematically so that Researchers, Engineers and Students are able to analyze the performance of corresponding communication systems quickly and straightforwardly. However, the derivation of analytic expressions for important performance metrics such as error rate and channel capacity is often cumbersome since complex integrals that involve combinations of elementary and special functions are required to be solved in closed-form. This talk discusses existing and recently proposed contributions in special functions and composite fading distributions and highlights their capabilities and usefulness in the analytical performance evaluation of classical and emerging wireless communication systems in generalised multipath/shadowing fading channels.

Speaker’s bio:
Paschalis Sofotasios was born in Volos, Greece in 1978. He received the M.Eng (Civilingenjör) degree from the University of Newcastle upon Tyne, UK, the M.Sc degree from the University of Surrey, UK and the Ph.D degree from the University of Leeds, UK. Since October 2010, he has been a Post-Doctoral Research Fellow at the University of Leeds and during Fall 2011 he was a Visiting Research Scholar at the CORES Lab in the University of California, Los Angeles (UCLA). His research interests are in the area of wireless communications with emphasis in fading channel characterization and modelling, single-channel and multi-channel systems, cognitive radio, cooperative systems and free-space-optical communications.

2012-05-04 Ex-jobbspresentation: "A 1 MHz Bandwidth, 90 nm CMOS Fractional-N Synthesizer Using Hybrid-ΔΣ-DA........"

Publicerad: 2012-05-02

Dawei Ye will present his Master's thesis "A 1 MHz Bandwidth, 90 nm CMOS Fractional-N Synthesizer Using Hybrid-ΔΣ-DAC-Based Phase Noise Cancellation Technique for LTE FDD/TDD" on Friday, May 4, at 15.15, in room E:3139.

All welcome!
Piero Andreani

Abstract
In this project, a 1MHz bandwidth, ΔΣ fractional-N PLL using phase noise cancellation path is designed as the frequency synthesizer for LTE FDD/TDD, where the phase noise cancellation path is composed of a ΔΣ DAC with equivalent 9 output bits. However, the actual performance of this phase noise cancellation technique is limited by the mismatch, nonlinear distortion and additive noise in the charge pump and ΔΣ DAC, respectively. Hence some advanced circuit topologies are developed to improve the system performance. At the first, the charges mismatch between the charge pump and current-steering DAC outputs can be decreased by introducing the digital shaped signals which are capable of increasing the overlapped region between their current pulses. Secondly, the timing offset pulses from the retiming circuit are feed to the charge pump in order to avoid the noise folding issue. Finally, a novel hybrid ΔΣ DAC with fine output resolution is creatively designed in order to reduce its quantization noise which will inject into the PLL when enabling the phase noise cancellation path. The performance and functionality of proposed PLL are verified by both the behavioral and transistor-level simulated results. The synthesizer is integrated in a 90 nm CMOS process and the PLL core and I/Q generators consume 14mA and 6.96mA from a 1 V supply, respectively.

2012-05-04 Exjobbspresentation: "Verification of a generalized Rayleigh-Debye-Ganz method for predicting the scattered from...."

Publicerad: 2012-05-02

On Friday, May 4, Tan Yi will present his master thesis project "Verification of a generalized Rayleigh-Debye-Ganz method for predicting the scattered from soot particles". The presentation is in E3139 at 10.15.

The thesis project is part of an ongoing collaboration between EIT and combustion physics. The aim of this collaboration is to find analytic and numerical methods to determine the morphology of soot particles.

Welcome!
Anders Karlsson

2012-04-27: Seminar; Memory Controllers for Real-Time Embedded Systems

Publicerad: 2012-04-19

Memory Controllers for Real-Time Embedded Systems

Benny Åkesson

Dr. Benny Åkesson, Eindhoven University of Technology

When and where:

April 27th, 11.00, in room E:3139

Abstract:

Designing multi-processor systems-on-chips becomes increasingly complex, as more applications with real-time requirements execute in parallel. System resources, such as memories, are shared between applications to reduce cost, causing their timing behavior to become inter-dependent. Using conventional simulation-based verification, this requires all concurrently executing applications to be verified together, resulting in a rapidly increasing verification complexity. Predictable and composable systems have been proposed to address this problem. Predictable systems provide bounds on performance, enabling formal analysis to be used as an alternative to simulation. Composable systems isolate applications temporally, enabling them to be verified independently.

Predictable and composable systems are built from predictable and composable resources. This presentation discusses concepts, architecture, configuration, and modeling of a predictable and composable memory controller. The controller design is general and supports both SRAM and SDRAM and a wide range of arbiters, making it suitable for many predictable and composable systems. The memory controller is supported by a configuration tool that automatically computes appropriate configuration settings, given bandwidth and latency requirements of the memory clients. The modeling approach is based on a shared-resource abstraction that covers any combination of supported memory and arbiter and enables system-level performance analysis with a variety of well-known frameworks, such as network calculus or data-flow analysis.

The memory controller is positioned with respect to existing work, targeting either firm real-time (FRT) systems or soft/no real-time (SRT/NRT) systems. The requirements of complex mixed real-time (MRT) systems, which contain a combination of FRT, SRT, and NRT memory clients, are presented and we explain why current controllers are unable to satisfy these requirements. As a direction for future research, we discuss how current FRT and SRT/NRT memory controllers may evolve into MRT controllers, suitable for complex systems-on-chips.

Biography:

Benny Akesson was born in Landskrona, Sweden in 1977. He earned a M.Sc. degree in Computer Science and Engineering at Lund Institute of Technology, Sweden in 2005. In 2010, He received his Ph.D. degree in Electrical Engineering at Eindhoven University of Technology, the Netherlands, on the topic of "Predictable and Composable SoC Memory Controllers". This research was conducted in collaboration with NXP Semiconductors. Dr. Åkesson is currently working as an assistant professor at the Eindhoven University of Technology, where he is leading the memory research team in the Electronic Systems group at the faculty of Electrical Engineering. His research interests include memory controller architectures, real-time resource scheduling, performance modeling, and virtualization. He is the author of a book about memory controllers for real-time embedded systems.

2012-04-26: Seminar; Passive and Active Engineering of Metamaterial-inspired Electrically Small Radiating Systems

Publicerad: 2012-04-17

EIT's being visited by Professor Richard W. Ziolkowski from University of Arizona on Thursday 26th of April. At 15.15 that day, he'll give a seminar in E:2349, entiteled 'Passive and Active Engineering of Metamaterial-inspired Electrically Small Radiating Systems'.

Richard Ziolkowski

Title
Passive and Active Engineering of Metamaterial-inspired Electrically Small Radiating Systems

Speaker: Prof. Richard W. Ziolkowski
Litton Industries John M. Leonis Distinguished Professor
Department of Electrical and Computer Engineering,
University of Arizona, Tucson, AZ 85721

Abstract
A number of advances in the use of metamaterial-inspired constructs to improve the overall efficiency, directivity and bandwidth performance of electrically small antennas (ESAs) in the VHF, UHF and microwave regimes will be reviewed. Several metamaterial-inspired ESA designs have been fabricated and tested; these measurement results are in nice agreement with predictions. While initial efforts emphasized simply high overall efficiencies without using any external matching networks, more recent resonant near-field parasitic (NFRP) designs have also explored the ability to exhibit multi-functional performance, higher directivity and enhanced bandwidths. Multi-functionality is achieved by combining multiple NFRP elements in an electrically small package. Higher directivity from an electrically small system is obtained by augmenting the NFRP antenna with structured ground planes. Enhanced bandwidths are achieved in an electrically small system by augmenting the NFRP antenna internally with non-Foster (active) elements, which are implemented as negative impedance convertor (NIC)-based inductors and capacitors. The possibility to develop an electrically small system sharing all of these interesting characteristics will be discussed. Time permitting, connections to similar enhanced performance radiating at higher frequencies, i.e., millimeter wave, terahertz and optical systems, will also be given.

More
Richard W. Ziolkowski (ScB 1974, Brown University, MS'75 and PhD'80 from the University of Illinois at Urbana-Champaign, all in Physics) is the Litton Industries John M. Leonis Distinguished Professor in the Department of Electrical and Computer Engineering at the University of Arizona. He is also a Professor in the College of Optical Sciences at the University of Arizona. He was the Computational Electronics and Electromagnetics Thrust Area Leader in the Engineering Research Division at the Lawrence Livermore National Laboratory before joining the University of Arizona in 1990. Professor Ziolkowski is a Fellow of both the Institute of Electrical and Electronics Engineers (IEEE) and the Optical Society of America (OSA). He was President of the IEEE Antennas and Propagation Society in 2005. He and Prof. Nader Engheta, University of Pennsylvania, are Co-Editors of the best selling 2006 IEEE-Wiley book, Metamaterials: Physics and Engineering Explorations.

Where and when
In room E:2349, Thursday April 26th. Welcome!

2012-04-23 Exjobbspresentation: BEAST on FPGA

Publicerad: 2012-04-20

Ali Roman will present his Master Thesis "BEAST on FPGA" on Monday at 10:15 in E:3139.

Welcome!
Joachim Rodrigues

Abstract
Data decoders and decoding processes in modern communication systems are of significant importance for data reliability. The key challenge for a designer is to en- sure data reliability. With development of different channel coding schemes, variety of decoding algorithms are devised. The role of a hardware designer is to provide an efficient implementation of those algorithms for different hardware platforms. This thesis focuses on the hardware implementation of the BEAST (Bidirectional Efficient Algorithm for Searching Code trees) for decoding of block codes. A com- plete hardware is designed to implement the strategy of the BEAST[1][3]. The design is described using VHDL language. Besides describing the implementa-tion of the BEAST for FPGA (Field Programmable Gate Array) based platform, ASIC (Application Specific Integrated Circuits) synthesis of the design for an ASIC implementation is also discussed. Synthesis is a process of mapping the design com- ponents on basic logic gates. The results of the synthesis process can be used for implementation of the design on an ASIC platform. The architecture of the design is synthesized by using 130nm CMOS technology, resulting in area of 0.72469 mm2 and maximum clock frequency of 143 MHz. BER (Bit Error Rate) simulation is performed to verify the performance of the system for different SNR (Signal to Noise Ratio) values.

2012-04-20 Exjobbspresentation:

Publicerad: 2012-04-18

On Friday, Parthiban Rameshkumar and Haridass Selvaraj will present their master thesis
“Bit error rate evaluation of MAP detection of block-fading non-coherent MIMO channels with and without knowledge of the channel statistics".

Time and place: 20/4 kl.11.15 in E:3139

You are all welcome!
Fredrik Rusek

När:	2012-04-21

 

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2012-04-18: Seminar; Faster-than-Nyquist and beyond: how to improve spectral efficiency by accepting interference

Publicerad: 2012-04-17

The COM-group invites you all to the following seminar:

Andrea Modenini

Title
Faster-than-Nyquist and beyond: how to improve spectral efficiency by accepting interference

Speaker: Andrea Modenini, University of Parma (guest student at EIT)

Where and when
April 18 at 15.15 in E:2311

Abstract
Faster-than-Nyquist signaling (FTN) is a well known technique consisting of reducing the spacing between two adjacent pulses in the time-domain well below the Nyquist rate, thus introducing ISI. If the receiver is able to cope with the interference, the efficiency of the communication system will be increased.

In this talk, we will investigate the improvements that can be obtained on AWGN channel and Nonlinear Satellite channel by receivers based on linear processing plus symbol-by-symbol detection or receivers based on a more sophisticated trellis processing with constrained complexity.

The potential advantage of the proposed signalling scheme when combined with conventional low-density parity-check (LDPC) coding of the DVB-S2 air interface will be presented.

När:	2012-04-19

 

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2012-04-19: Electromagnetic Theory research seminar: Andreas Ioannidis

Publicerad: 2012-04-17

Electromagnetic Theory research seminar: Andreas Ioannidis,
Well posedness and stability issues with applications in Electromagnetics,
Thursday April 19 at 13.15 in E:2349.
http://www.eit.lth.se/index.php?id=574&no_cache=1&L=1&gpuid=169

När:	2012-04-19

 

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2012-04-16 Presentation: "RF Systems at Maxlab and Max IV"

Publicerad: 2012-04-03

April 16, at 15.15 in room E:2311, Lars Malmgren will give a presentation on RF Systems at Maxlab and Max IV. This is the same presentation as he gave at the GigaHertz conference in March, which was highly appreciated by the conference participants.

You are most welcome to attend the presentation!
Henrik Sjöland

Abstract:
MAX-lab is a national laboratory operated jointly by the Swedish Research Council, and Lund University. Yearly more than 800 individual researchers use the laboratory to carry out experiments in many different areas. The MAX IV project, which is the next generation synchrotron radiation facility in Sweden, will replace the existing laboratory when finished. RF systems are a vital part of all electron accelerators which are used both for acceleration of electrons and for beam diagnostics. The presentation will focus on RF accelerating structures, RF power sources, RF distribution, beam loading and low level RF (LLRF) and beam position monitors (BPM).

När:	2012-04-18

 

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2012-04-13 Seminar: OAM-based wireless communication

Publicerad: 2012-04-03

Orbital angular momentum - the future of wireless communications?

ABSTRACT
The last few years there have been repeated claims from parts of the physics community that the orbital angular momentum (OAM) properties of the electromagnetic field have not yet been utilized for communication in the RF range of frequencies. A revolution has been promised in the area of wireless communications, with almost infinite increase of capacity (spectral efficiency) if OAM is exploited. The new technique was demonstrated publicly in Venice, Italy, in June 2011. We will describe the history of these claims, tracing them back to 2007, and try to translate the results from the physics context to a wireless communications context. Along the way, we hope to answer the question posed in the title.

For a quick introduction to the Venice experiment, there is a very recent paper (and a video abstract) here

WHEN/WHERE
Friday April 13, at 13.13 in E:2311

You are all welcome,
Ove Edfors and Anders J Johansson

När:	2012-04-14

 

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2012-04-13 Forskningsseminarium, Teoretisk elektroteknik

Publicerad: 2012-04-11

Forskningsseminarium, Teoretisk elektroteknik: Rebecca Seviour, Microwave Metamaterial and Photonic Interactions, Fredag den 13 april kl 15.15 i E:2349. http://www.eit.lth.se/index.php?id=574&no_cache=1&L=1&gpuid=169

När:	2012-04-14

 

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Ex-jobbspresentation: "Event processing in large-scale social network systems"

Publicerad: 2012-04-03

Jens Andersson (D07) and Johan Mattson (D07) will present their master project
"Event processing in large-scale social network systems"
that they have performed at ProjectPlace International in Stockholm.
Time and place: 4/4 kl.10.15 in E:3139

You are all welcome!
Maria Kihl

Abstract:
Social networks are becoming increasingly popular, with the business arena seeing a large growth. People are getting used to performing more and more actions in the web and expects to see results in real-time. With the increase in user base as well as more functionality, the amount of data is increasing fast. To handle this growth in data and higher demands on real-time, new software architectures are needed. This thesis aims to investigate and propose new ways of designing web systems to handle these demands. With the large growth in event generation, data analysis becomes complex and time consuming. Analyzing event logs is important from both a maintenance and business point of view, giving feedback of system usage proposes new business opportunities. This thesis will also investigate new open source technologies with the ability to process and analyse large data sets. This thesis has been a collaboration with Projectplace International AB. Projectplace is a leading social project collaboration tool in Europe; a social network where businesses collaborate in the cloud. B2B (Business to Business) collaboration at Projectplace consists, for instance, of sharing documents, scheduling work and interacting with co-workers.

När:	2012-04-06

 

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Seminar: "Design for Test"

Publicerad: 2012-03-26

Erik Larsson will give a seminar on "Design for Test"
March 30th 11:00 E:3139

Design for Test (DfT) is today common practice for most electronics. However, many are not everyone familiar with basic concepts, and there are still many open questions. This talk consists of two parts. In the first part, we introduce the basics of DfT, which includes defects, fault models, test generation, scan-chains and built-in self-test. In the second part, we discuss on-going research on test planning, which includes work on core-based system-on-chips, stacked chips, and access mechanisms for embedded test and debug features, as well as design for graceful degradation and post-silicon debug.

När:	2012-04-01

 

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Ex-jobbspresentation: "Higher order mode coupler for the MaxIV storage ring"

Publicerad: 2012-03-27

On Friday 30 March at 14.15 in E:2311, Samra Assemnew will present her Master thesis project "Higher order mode coupler for the MaxIV storage ring".

You are all most welcome!
Anders Karlsson

Abstract
This thesis work is based on the advanced photon source project MAX IV at Lund University. MAX IV is a synchrotron radiation facility with two storage rings. There is an inherent problem in the storage ring RF cavities due to the existence of higher order modes (HOM). These HOMs, in particular the TM modes, cause system instability by interfering with the beam. To cope up this problem a special kind of damper referred to as HOM coupler and a notch filter are used. The damper couples out the HOM and reduce the system instability. Subsequently, the notch filter blocks the TM wave at the accelerating frequency of 102.4 MHZ and guide the other HOM to be terminated by the 50 load. In order to test the effect of the damper and the notch filter, simulations with Comsol software and measurements with a network analyser are performed. The results of the two output are compared. Both results show that the damper efficiently damps the HOM that have a strong field around the coupler while the modes with weak fields are not sufficiently damped.

När:	2012-04-01

 

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Licentiatavhandling:Tobias Tired

Publicerad: 2012-03-05

Fredagen den 23 mars 2012 kl 10.15, presenterar Tobias Tired sin licentiatavhandling "High Perfromance LNAs and Mixers for Direct Conversion Receivers in BiCMOS and CMOS Technologies" i sal E:2311 i E-huset.
Handledare: Pietro Andreani

Ladda hem licentiatavhandlingen

Abstract
The trend in cellular chipset design today is to incorporate support for a larger number of frequency bands for each new chipset generation. If the chipset also supports receiver diversity two low noise amplifiers (LNAs) are required for each frequency band. This is however associated with an increase of off-chip components, i.e. matching components for the LNA inputs, as well as complex routing of the RF input signals. If balanced LNAs are implemented the routing complexity is further increased. The first presented work in this thesis is a novel multiband low noise single ended LNA and mixer architecture. The mixer has a novel feedback loop suppressing both second order distortion as well as DC-offset. The performance, verified by Monte Carlo simulations, is sufficient for a WCDMA application. The second presented work is a single ended multiband LNA with programmable integrated matching. The LNA is connected to an on-chip tunable balun generating differential RF signals for a differential mixer. The combination of the narrow band input matching and narrow band balun of the presented LNA is beneficial for suppressing third harmonic downconversion of a WLAN interferer. The single ended architecture has great advantages regarding PCB routing of the RF input signals but is on the other hand more sensitive to common mode interferers, e.g. ground, supply and substrate noise. An analysis of direct conversion receiver requirements is presented together with an overview of different LNA and mixer architectures in both BiCMOS and CMOS technology.

När:	2012-03-25

 

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Ex-jobbspresentation: "Multi-sector cooperation in multi-user MIMO for a measured urban macrocellular environment"

Publicerad: 2012-03-16

On Thursday 22 March at 15.15 (in E:2349), Ningxin Chen will present her Master Thesis on the topic "Multi-sector cooperation in multi-user MIMO for a measured urban macrocellular environment".

Abstract
This master thesis mainly studies the benefits of multi-sector cooperation in the radio bast station (BS) of a multi-user multiple input multiple output (MU-MIMO) system. The performance evaluation is performed using intra-site coordinated multi-point (CoMP) channel measurements in an urban macro cellular environment at the carrier frequency of 2.65 GHz. The focus of the analysis is to investigate the MU-MIMO capacity gain enabled by three-sector cooperation in a single BS site for both multiple access channel (MAC) and broadcast channel (BC). To simplify the complexity of the calculation, we study the two-user scenario. To calculate the sum rate capacity, joint decoding is assumed in the MAC case. Due to the complexity in maximization of the transmit covariance matrix and minimization of the noise correlation matrix in the BC case, uplink-downlink duality between the MAC and the BC is applied to obtain the capacity in the BC case. The results show that, on average, the MU-MIMO capacity gain introduced by the three-sector cooperation is about 40% and 60% in MAC and BC, respectively. When it comes to the outage performance, 10% of the measured positions have capacity gains of over 60% and 100%, in MAC and BC, respectively. Furthermore, when one user is fixed at the center of each sector, the capacity gain is maximum when the other user moves to the back lobe of the sector. On the other hand, when one user is fixed at the edge of two neighboring sectors, the capacity can be greatly improved when the other user moves in the coverage area of the third sector. The same conclusions can be obtained in both MAC and BC cases. To summarize, using multi-sector cooperation in an intrasite CoMP system exhibits great potential for improving the capacity performance in MU-MIMO systems.

När:	2012-03-24

 

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Ex-jobbspresentation, "A 2.4GHz low power Phase-Locked Loop in 65 nm CMOS"

Publicerad: 2012-03-13

Tisdagen den 20 mars kl 15.00 presenterar Lu Aijun sitt ex-jobb "A 2.4GHz low power Phase-Locked Loop in 65 nm CMOS" i sal E:3139 i E-huset.

Välkomna
Carl Bryant

Abstract
The development in wireless communication has driven universities and companies to research and develop low-power, small size transceivers. Low-power short-range wireless systems find application in wireless sensor networks, RF identification (RFID) systems, and implantable medical devices, where the Phase-Locked Loop (PLL) is a critical part of the wireless transceiver system. In this paper, a 2.4GHz 247uW Phase-Locked Loop (PLL) for a wireless transceiver system, is designed and simulated in 65nm CMOS technology. In order to achieve the ultra low-power goal, a Voltage Controlled Oscillator (VCO) using an LC-Tank topology with 0.5V core supply voltage is implemented. An integer divider based on the True Phase Single Clock (TSPC) D-flip-flop is carefully designed to further reduce the power consuming. The PLL is realized in ST Microelectronics 65nm CMOS process, the simulated results show that the system achieves a phase noise of - 107.3dBc/Hz at 1MHz offset and -122dBc/Hz at 3MHz offset while consuming only 247uW.

När:	2012-03-23

 

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Seminarium: Joerg Kliewer

Publicerad: 2012-03-15

Joerg Kliewer, who has been offered the ELLIIT-position as Professor of Communications Engineering at EIT, will give a seminar when he visits Lund next week.
Title: Coding strategies for physical-layer security (tentative)
When/where: Tuesday March 20, at 09.15 in E:2311

Welcome!

/Ove Edfors

När:	2012-03-22

 

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Två professorer vid EIT installeras!

Publicerad: 2012-03-07

Vid professorsinstallationen fredag 16 mars kommer två nyblivna professorer vid EIT att installeras: Mats Gustafsson och Daniel Sjöberg, båda i ämnet teoretisk elektroteknik. Installationen äger rum i universitetsaulan, och börjar kl 16.00.

När:	2012-03-21

Mer information

 

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Populärvetenskapliga föredrag

Publicerad: 2012-03-07

Under 5-9 mars hålls ett flertal populärvetenskapliga föredrag på EIT med anledning av NMT-dagarna, då flera tusen gymnasieungdomar besöker naturvetenskapliga, medicinska och tekniska fakulteterna vid Lunds universitet. Titlar och föredragshållare från EIT:

Att knäcka ett lösenord - Martin Hell
Elektromagnetiska fält - Richard Lundin
Finns internet? Men varför fungerar det då? - Jens Andersson
Hur skapar vi "glasögon" för öronen? - Nedelko Grbic
Isn´t Moore Enough?- Elektronikrevolutionen - Viktor Öwall
Osynlighet- hur gör verklighetens Harry Potter? - Daniel Sjöberg
Radiovågor- livräddare vid laviner, jordbävningar och andra naturkatastrofer - Fredrik Tufvesson

När:	2012-03-12

 

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Disputation Peter Hammarberg

Publicerad: 2012-02-02

Datum: 2012-02-24, kl 10:15
Plats: Lecture hall E:1406, E-building, Ole Römers väg 3, Lund University Faculty of Engineering
Opponent: Professor Bernard Fleury . Dept of Electronic Systems, Aalborg University, Denmark
P. Hammarberg:
Iterative receivers with channel estimation for MIMO and multi-user OFDM systems
Series of Licentiate and Doctoral Theses, ISSN 1654-790X No. 37, Dpt. of Electrical and Information Technology, Lund University, Sweden, 2012.
Abstract: The traffic in wireless networks has been showing an exponential growth over the last decade. In order to meet the demand, and support a continuation of this growth, the scarce radio resources need to be efficiently used. The use of multiple antenna (MIMO) systems and iterative (turbo) receivers has significantly improved the realizable system performance. Still, many challenges exist in the development of efficient wireless receivers. In this thesis, which is written in the form of a collection of papers, we have investigated and developed iterative receivers with channel estimation for multi-user systems.
Paper I investigates different iterative receiver algorithms for an uplink multi-user MIMO orthogonal frequency division multiplex (OFDM) system. For the given receiver structure, different combinations of multi-user detectors (MUD) and decision-directed channel estimators are compared. The comparison focuses on the complexity-performance tradeoff for the receiver configurations. The results show that low complexity algorithms, despite requiring more receiver iterations, tend to have the lowest overall complexity for a given bit error rate (BER).
Paper II presents how the convergence behavior of an iterative receiver with channel estimation for an uplink multi-user MIMO-OFDM system can be modeled through multi-dimensional extrinsic information transfer (EXIT) charts. Although single-input single-output EXIT charts have been well studied, the multiple input-output case has generally been overlooked in the literature. Such charts are suitable for studying multi-user systems. The presented EXIT chart predictions show good correspondence with the true convergence behavior of the receiver.
Paper III discusses the use of channel measurement data in system evaluations. We discuss and exemplify a number of issues related to the use of such data, and also provide potential solutions. The issues include problems with measurement noise and measurement antenna directivity.
Paper IV investigates the performance gains that can be harvested through base station cooperation in an uplink multi-user MIMO-OFDM system. An iterative receiver with channel estimation is evaluated using unique mobile dual-link MIMO channel measurement data. The results point at the large performance gains which can be harvested through cooperative processing in a real environment.
Paper V presents and evaluates a number of channel estimation algorithms for an OFDM interleave division multiple access (IDMA) system. We look at different pilot based algorithms as well as decision-directed algorithms being part of the iterative process of the receiver. As for paper I, the comparison focuses on the complexity-performance tradeoff, and the results show that low-complexity algorithms can be competitive alternatives when looking at the overall receiver complexity.

När:	2012-02-24

 

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Exjobbspresentation: "Security Performance Issues in P2P Cloud Computing"

Publicerad: 2012-02-15

On Friday 17/2 at 10.15 in E:3139, Tugba Tanören will present her master thesis titled "Security Performance Issues in P2P Cloud Computing". The project has been funded by Ericsson AB.

You are all welcome to attend!
Maria Kihl and Ben Smeets

Abstract:
This Master Thesis project has been performed and supervised in cooperation with Ericsson AB and the EIT department at LTH. The thesis is a first attempt to investigate some of the performance issues in P2P Cloud Computing. It investigates state-of-the-art P2P Cloud Computing, especially Content Delivery Network (CDN) based on P2P and how security protocols affect the performance of these systems. A central part of P2P systems are Distributed Hash Table (DHT) algorithms and the focus of this thesis is to investigate this subsystem of the P2P Cloud Computing. The DHT algorithm chosen to be simulated was Content Addressable Network (CAN). The results come from a realistic simulation environment called ns-3. Ns-3 is a open source discrete-event network simulator and its behavior is highly trusted within the networking community. Since ns-3 is a network simulator the focus in this thesis is on network security. Datagram Transport Layer Security (DTLS) was chosen to secure communication since the CAN implementation builds on UDP connections. The results presented shows the difference in performance parameters such as latency and bandwidth with and without DTLS.

När:	2012-02-18

 

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Ex-jobbspresentation: "Säkra Androidapplikationer genom kontrollerande ramverk"

Publicerad: 2012-01-26

Välkomna till redovisningen av Andreas Norden's exjobb: Säkra Androidapplikationer genom kontrollerande ramverk den 27 januari kl 10.00 i sal E:3139, E-huset, LTH. Exjobbet utfördes hos Combitech med Martin Söderstjerna som handledare.

Välkomna
Ben Smeets

Sammanfattning:
I rapporten undersöks möjligheterna att utveckla ett ramverk som garanterar säkerheten för information som behandlas applikationer anslutna till ramverket. Målet är att hitta ett sätt att minska utvecklingskostnaden för betrodda applikationer genom att minska behovet av säkerhetsgranskning och certifiering. Detta utan att minska säkerheten för informationen som hanteras. I undersökningen implementeras en prototyp till ett ramverk för övervakning och tillhandahållande av resurser. Resultatet visar dock inte på någon stabil metod för övervakning av andra applikationer. Däremot visas att ett ramverk för tillhandahållande av exempelvis kryptering är lämplig på en androidtelefon, en sådan lösning skulle kunna minska utvecklingskostnaden för säkra applikationer.

När:	2012-01-28

 

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2012-01-24 Seminarium av den nye professorn, Björn Landfeldt

Publicerad: 2012-01-04

Mellan den 23 och 27 januari får vi besök av Björn Landfeldt som senare under året kommer att påbörja sin tjänst som professor i nätverksarkitektur. Tjänsten är finansierad med stöd av ELLIIT.

Tisdagen den 24 januari, kl. 13.15, kommer Björn hålla i ett seminarium i E:2311. Seminariet (se titel och sammanfattning på egnelska nedan) kommer att vara en presentation på cirka 45 minuter, följt av frågor och diskussioner.

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Title:
Understanding and Harnessing Extremely Dynamic Wireless Networks

Abstract: In this talk, I will outline some of the research challenges and problem areas I am currently pursuing in the field of wireless networks, with the intent of establishing connections and collaborations locally at LTH.

Wireless network constructs are rapidly developing and diversifying to encompass a multitude of technologies and application areas. Cellular networks are still growing at a phenomenal rate and the acceptance of the untethered communications mode has given rise to a plethora of alternative wireless systems paradigms such as WLANs, mobile adhoc networks, mesh networks, vehicular ad hoc networks and sensor networks. Even though these newer constructs are generally separated as specific areas for convenience in the research community, they share a number of fundamental properties that differ significantly from the traditional cellular case. Even cellular networks are being affected by these properties through the integration of multiple access technologies through standardisation efforts such as Generic Access Networks (GAN) from the ITU-T.

There are many fundamental factors that lead to these new properties such as the ever present spectrum scarcity which leads to efforts in spectrum reuse, the introduction of femto cells as well as the use of unlicensed spectrum. From an architectural point of view, all these efforts and new constructs turn the centralised coordination paradigm on its head, leading towards highly distributed systems where individual network components assume increased responsibility and operate in collaboration with other components.

As communication becomes increasingly short range and also increasingly mobile, the operational conditions for the wireless nodes varies at a very high rate; in other words, wireless networks become extremely dynamic. Currently, it is not well understood how to construct network architectures that can cope with this dynamic environment. In fact, many of the basic mechanisms of current state of the art wireless networks were designed for quasi-stable networks and they are not suitable for use in highly dynamic networks.

Stepping away from access networks, a further very important aspect of some of the new network paradigms is that they are deployed in symbiosis with a host system. For example, sensor networks can be deployed in mines where the layout of the mine shafts dictate possible deployment configurations, vehicular networks are deployed onboard vehicles and hence the network composition follows road traffic movement etc. In order to fully understand such networks and be able to device appropriate mechanisms and communication architectures it is absolutely vital to understand and model the host system first, before translating this knowledge onto the behaviour of the wireless symbiotic network.

In this talk, I will provide examples from work I am currently undertaking in this space and specifically point out the need for multiple disciplines to come together in order to solve the challenging problems that lie ahead.

När:	2012-01-25

 

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Ex-jobbspresentation: En universell dörrprocessor

Publicerad: 2012-01-19

Morgan Persson presenterar sitt examensarbete "En universell dörrprocessor" på fredag den 20/1 2012 kl 10.15 i sal E:3139, Ole Römers väg 3, E-huset.

Välkomna!
Bertil Lindvall och Mats Cedervall

Beskrivning
Målet är att ta fram en nätverksansluten styrenhet med ett gränssnitt som kan användas tillsammans med olika typer av läsare, dörrar och databaser. Installationen ska vara enkel och gärna kunna utnyttja befintligt kablage. Genom att hålla strömförbrukningen på en låg nivå undviks stora batterier vid behov av batteribackup och den totala strömförbrukningen minimeras. Det ska också vara möjligt att bygga vidare på systemet för integration med befintliga passagesystem eller t.ex. fastighetsautomation. En demonstrator som hanterar minst en dörr ska tas fram och provas tillsammans med en lämplig dörr.

När:	2012-01-21

 

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Ex-jobbspresentation: Signal Integrity Analysis of Package and PCB for High Speed Data link Application

Publicerad: 2012-01-17

On Wednesday 18/1 at 13.15 in E:2349, will: Sreejith Palleeluveedu Raghavan present his Master’s thesis:

Signal Integrity Analysis of Package and PCB for High Speed Data link Application

The thesis is done in cooperation with Texas Instrument
You are all welcome!

Peter

ABSTRACT
With ever shrinking geometry size, we have reached a point in time in which we cannot draw a direct correlation of the performance of the IC design with respect to the number of transistors on a single chip. As in limited silicon area available factors like tighter packaging space, circuit boards and increasing clock frequencies, packaging issues and system-level performance issues such as crosstalk and transmission lines are becoming increasingly significant. Multi chip packages and increased IO counts are forcing package design to become more challenging like chip design [1] .This thesis targets a fundamental evaluation of variety of approaches in board design viz. varying the length, width, and design structure for a high speed electrical channel. The application of electrical interface is simulated with HSPICE® software. It also demonstrates the jitter variation effect by the use of microstrip versus stripline traces. The jitter results for various line parameters and line terminations are compared with results published in literature. The crosstalk between coupled microstrip lines in both “time” and “frequency” domain are presented and simulated in HSPICE®. In addition the thesis studies with simulation results, shows that ground conductors need to be placed in between the aggressor and victim to reduce crosstalk effectively. However the presence of the grounded conductors will increase the layout complexity and waveform distortion for the signal on the aggressor line. The crosstalk analysis in frequency domain for different packages had been analyzed and simulated. A crosstalk and jitter minimization technique was implemented in 2D field solver for both package and board. The rated frequency at which DDR3 sub-systems are targeted in Texas Instruments (TI) designs showed a 10% reduction in the expected frequency of operation, after accounting the various extraneous parameters obtained as part of the thesis findings. This is based on the assumption that they are linearly accounted in to the link layer timing calculation, but from a Gaussian distribution curve the effective impact is root-sum-square of the results obtained.

När:	2012-01-19

 

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Ex-jobbspresentation: Custom-Cell Design for Sub-VT Memories

Publicerad: 2012-01-10

Babak Mohammadi will present his master thesis, Custom-Cell Design for Sub-VT Memories, on Friday 13th at 0915 in E:2311.

Abstract
Supply voltage scaling is a very popular technique to reduce energy dissipation. Digital design may be synthesized with standard-cell libraries where designers ac- cept that the gates are not working optimally, and hard macros like RAM may not work at all at aggressive scaled supply voltages. Therefore, it is desirable to a small standard cell library that is feasible for automized memory generation. In this project various leakage minimization techniques like transistor stacking, transistor channel stretching and hardware minimization is evaluated. The target technology is 65 nm CMOS.

Welcome
Joachim Rodrigues

När:	2012-01-14

 

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