Event archive, 2014
Symposium Gerhard Kristensson
Ämne: Symposium Gerhard Kristensson Datum: 15 Januari, 2015 Tid: 10.00-16.10 Plats: E1406, E-Huset, LTH Gerhard Kristensson pensioneras den 31 december 2014. Han har genom åren skapat nationella nätverk inom elektromagnetisk fältteori och därigenom varit viktig för svenska universitet, högskolor, forskningsinstitut och företag. Vid symposiet som hålls den 15 januari 2015 kommer Gerhards vetenskapliga vänner från dessa nätverk att träffas och visa sin uppskattning för hans insatser. Vi kommer att lyssna på presentationer som knyter an till Gerhards verksamheter. Luckorna för kafferaster och lunch är väl tilltagna och det finns gott om tid att umgås, prata minnen eller diskutera framtiden. Dagen avslutas med en middag på en trevlig restaurang. Vi kommer så småningom att presentera ett detaljerat program för dagen. Redan nu kan vi ge följande tidsschema: 10:00 Samling i E1406 i E-huset på LTH. 10:00-10:40 Kaffe och tilltugg 10:40-12:00 Presentationer 12:00-13:30 Lunch 13:40-14:40 Presentationer 14:40-15:10 Kaffe 15:10-16:00 Presentationer 16:00-16:10 Avslutning 18:30 Middag
Seminar “Algorithms for FDD-based Massive MIMO”
Speaker: Andreas Molisch
Date: 18 Dec, 2014
Massive MIMO is one of the hottest research topics, due to the promise of increased capacity and simplified multi-user beamforming. In order to reduce overhead for obtaining the requisite channel state information at the transmitter (CSIT) in the downlink, most of the current research focuses on TDD-based massive MIMO systems where channel reciprocity can be exploited. On the other hand, most of the current cellular systems are FDD-based. In this talk we will thus discuss two methods for obtaining low overhead for CSIT in FDD systems. Both methods exploit the small angular spread typically occurring at the base station (BS). The first scheme, JSDM, transforms the signals into beamspace (based on the second-order channel statistics), and assigns channels there). The second approach operates directly in the correlation-matrix space, and obtains optimized training sequences and feedback codebooks. At the expense of higher computational complexity, it obtains often better performance than JSDM. In either case, exploitation of spatial correlation allows a drastic reduction of overhead, and makes FDD competitive with TDD massive MIMO systems.
Disputation Carl Gustafson
Date: 2014-12-17, kl 10:15
Place: E:B (Not E1406!) E-building, Ole Römers väg 3, Lund University Faculty of Engineering
Welcome to attend Carl Gustafsons disputation where he defends his doctoral dissertation "60 GHz Wireless Propagation Channels: Characterization, Modeling and Evaluation". Opponent is Professor Jie Zhang, University of Sheffield.
To be able to connect wirelessly to the internet is nowadays a part of everyday life and the number of wireless devices accessing wireless networks worldwide are increasing rapidly. However, with the increasing number of wireless devices and applications and the amount available bandwidth, spectrum shortage is an issue. A promising way to increase the amount of available spectrum is to utilize frequency bands in the mm-wave range of 30-300 GHz that previously have not been used for typical consumer applications. The 60 GHz band has been pointed out as a good candidate for short range, high data rate communications, as the amount of available bandwidth is at least 5 GHz worldwide, with most countries having 7 GHz of bandwidth available in this band. This large bandwidth is expected to allow for wireless communication with bit rates up to 7 Gbit/s, which can be compared to the typical WLAN systems of today that typically provide bit rates up to 0.6 Gbit/s. However, the performance of any wireless system is highly dependent on the properties and characteristics of the wireless propagation channel. A lot of research has been dedicated to the characterization and modeling of propagation channel properties for frequencies up to 10 GHz. However, due to the much shorter wavelengths, the propagation channel properties for mm-wave bands are quite different from those of lower frequency bands. For this reason, a lot of new research has to be conducted to characterize, model and evaluate the propagation channel properties for mm-Wave bands.
This thesis contributes to an increased understanding and knowledge of the behavior and characteristics of propagation channels for mm-wave systems in general and for 60 GHz systems in particular. The results in the thesis are thus useful for the design and development of future wireless systems in the mm-wave range.
Seminar by Said Mikki
Date: Thursday December 11
Time: 11.15 - 12.00
Said Mikki, research fellow, Department of Electrical and Computer Engineering, Royal Military College of Canada, Kingston, Ontario, Canada
New Perspectives on Electromagnetic Near Fields, Energy, Mutual Coupling, and Antenna Current Distribution Engineering
The talk will visit several topics of wide and current interest within applied electromagnetic research viewed in light of recent progress in fundamental electromagnetic theory. The emerging areas of near field engineering and the problem of energy in antenna systems will be illuminated from the perspectives of both physical theory and related engineering applications. The recently introduced antenna current Green’s function formalism for the characterization of general antenna systems under generic excitation/illumination will be presented and applied to the formulation and solution of mutual coupling problems in examples that include MIMO and Near Field Communication systems valid for arbitrary array topologies and element specifications. The talk will also outline recent progress in antenna current distribution engineering understood as the systematic method of designing antennas for special applications by controlling the current distribution on the radiating elements themselves. This theme of current engineering will be approached through the new near field and the antenna current Green’s function theories with applications to, for example, DoA, MIMO, and antenna current characteristic modes. The talk will also provide demonstrations of how fundamental theory can provide proposals for radically new experiments in the domains of near field measurement and advanced antenna characterizations.
2014-12-08 Massive MIMO workshop @ IEEE GLOBECOM 2014 (Austin, TX)
EIT researchers in Massive MIMO will arrange a workshop (December 8th) at IEEE GLOBECOM 2014 in Austin, TX.
"Massive MIMO: From theory to practice"
Read more: mamiws.eit.lth.se
Master Thesis presentation
Md. Ashraful Islam and Nasimul Hyder Maruf Bhuiyan will present their Master Thesis "The Effect of Radio Channel Modelling on the Network Performance in VANET"
Date and time: 2014-12-01 11:15 at E:3139
Supervisor: Maria Erman (BTH), Kaan Bür (EIT), Maria Kihl (EIT)
Examiner: Fredrik Tufvesson (EIT)
Research in vehicle-to-vehicle communication and the widely accepted Vehicular Ad Hoc Network (VANET) are two major fields of growing interest. The advent and recent development of these concepts foster evolution of the new paradigm of the transportation system, widely known as Intelligent Transport System (ITS). Among the numerous challenges in adopting VANET for ITS, modeling the radio channel is a vital one, because of the mobility of transmitters and receivers, low elevation of antennae, channel fading and statistically non-stationary of channels. A channel model has been proposed that agree with the above mentioned unique characteristics exist in designing VANET, i.e. Lund Model. In this work, we focus on data delivery performance at the network layer of a VANET under Lund propagation model and compare the performance with that of some of the existing models, e.g., three log distance model, friis model, nakagami model, which are commonly used for analyzing conventional wireless communications. Average delay per packet and total packet loss ratio are the two parameters used for comparing the performance. Simulation results indicate that Lund Model yields lower success rates with all other propagation loss models in both highway and rural scenario in terms of average delay per packet and total packet loss ratio as a result of its more realistic nature.
Nordic Test Forum, NTF and BASTION Workshop.
Date: 25-26 Nov 2014 Place: Radisson Blu Hotel, Malmö, Sweden The 2 day Nordic Test Forum is a major event for Test professionals in the Nordic area and Baltic states. Every year the Test Forum is attended by the industry’s key persons as well as by international vendors of test and measurement equipment and solutions. See more about NTF: See more about BASTION Workshop:
Seminar by Martin Stumpf
Date: Tuesday Nov 25
Time: 11.15 - 12.00
Speaker: Martin Stumpf, Assistant Professor, Brno University of Technology, Czech Republic
Title: Miscellaneous Applications of Time-Domain Reciprocity Theorems in Antenna Theory
Abstract: The great bulk of antenna theory leans heavily on the (real-)frequency-domain paradigm. Along with the emergence of pulse-based communication systems, however, there is a demand for purely time-domain (TD), causality-preserving concepts of antenna-system analysis.
This is exactly the line of reasoning followed in the presentation in which a brief review of some recently introduced, purely TD antenna concepts is given. This includes a reciprocity-based description of TD mutual coupling between two microstrip antennas, an extended TD Friis formula and a special form of the TD 'optical' theorem.
All welcome !
Datum: 2014-11-20 Tid: 14.06 Plats: E1406 Välkommen till höstens andra tårtseminarium. Föredragshållare är Sten Minör och titeln på föredraget är: ”En resa dit och tillbaks igen" Sten kommer berätta lite erfarenheter från sin resa ut i näringslivet och från samarbetet mellan akademi och industri han varit involverad i de senaste 15 åren.
Master Thesis presentation by Rui Ma and John Chountalas
Title: Pattern reconfigurable MIMO antennas for Multiband LTE Operation Students: Rui Ma and John Chountalas Supervisor: Dr Hui Li Date: Tuesday 18 Nov 2014 Place/Time: E3139, 13.15 Abstract Nowadays, multiple antennas are becoming widely used in small mobile terminals as they can significantly improve wireless communication performance in terms of link reliability and spectral efficiency. Also, pattern reconfiguration is another new trend for antenna design as it enables the antennas to adapt to different propagation and user scenarios. However, due to the limited space in the terminals, it is difficult to implement both techniques and obtain good antenna performance, especially for frequencies bands below 1 GHz. This is because the mobile chassis is often shared by different antennas as the main radiator, regardless of the antenna structure, which leads to high mutual coupling and correlation. In this thesis, a dual-band (824-894 MHz and 1,850-1,990 MHz) MIMO antenna system with pattern reconfiguration at the low band was designed based on the Theory of Characteristic Modes (TCM). The work began with the design of a reconfigurable single-antenna that can be switched between an inverted-F antenna (IFA) mode and a bezel mode, with low envelope correlation of around 0.2 between the states. This was followed by the implementation of a second antenna (i.e., a single-side T-strip) for MIMO operation. The inclusion of the second antenna required the antenna system to be re-optimized, and several performance trade-offs were observed and investigated, including the tradeoff in the mutual coupling between the MIMO antennas in different states, the tradeoff between the mutual coupling and the inter-state correlation. The final design of the pattern reconfigurable MIMO antennas yields an inter-state correlation of around 0.3, and an intra-state correlation of below 0.1 and 0.2, respectively. All the studies were carried out in CST Microwave Studio.
Campus Open Helsingborg
Välkommen till Helsingborg Campus Open
Tid: 14 Nov
Plats: Campus Helsingborg
Den 14 november arrangeras Campus Open där alla intresserade och nyfikna får möjlighet att ta del av ett axplock av forskningen. På årets Campus Open bjuder vi på 19 öppna föreläsningar inom så vitt skilda teman som lärande och motivation, framtidens teknik och mobiler, välfärdens stuprör, kommunikativt ledarskap, transportforskning och jämlikhet. Inleder gör Dunkers kulturhus chef Katti Hoflin, som pratar om konsten att skapa kreativitet och professor Peter Gärdenfors, som berättar om lusten att lära.
IVA-Syd seminar on mobile cloud and MAPCI
Date: 13 Nov Time: 17:00-19:00 Place: Mobilvägen 10, Lund Subject: IVA Syd invite to a seminar on "What is the mobile cloud and MAPCI?" MAPCI means "Mobile and Pervasive Computing Institute at Lund University" and is a collaborative research institute between academia, industry and the Skåne region. The main focus area of the institute is Mobile Cloud Computing and the mobile ecosystem building on the regional strength in systems design and control, software and hardware design in mobile and wireless systems. The institute was inaugurated in 2013 by the founding partners, Sony Mobile Communication, Region Skåne and Lund University. The seminar is free of charge but registration is needed. Please register at IVA homepage www.iva.se/kalendarium at the latest Nov 7. For more info, please contact Ulla Svantesson, 08-791 29 93, firstname.lastname@example.org.
Seminarium med Ulrike Richter
Datum: Onsdag 29/10 Tid: 12.15-13.00 Plats: E1406 Välkomna på LABIB seminarium, presenterat av Dr. Ulrike Richter från Integrativ Neurofysiologi, Medicinska fakulteten, Lunds Universitet. Seminariet har titeln ”På spår efter den neurala koden för våra rörelser”. Ulrike är doktor från EIT. Abstract: Neurovetenskap, både experimentell och teoretisk, har de senaste åren lyfts mer och mer i allmänhetens och forskarvärldens medvetande. Bidragit till detta har inte minst de europeiska och amerikanska projekten "Human Brain Project" och "Brain Initiative", och nu senast utdelningen av Nobelpriset i fysiologi eller medicin till O'Keefe och paret Moser. Forskningen inom denna högst interdisciplinära fält adresserar de mest fundamentala frågorna rörande hur vårt nervsystem fungerar. En av dessa frågor är hur olika delar av hjärnans motorsystem samverkar för att möjliggöra inlärning, selektering och genomföring av rörelser. Inom vår forskargrupp vid Institutionen för Experimentell Medicinsk Vetenskap och Neuronano Research Center har vi valt att studera denna frågeställning i såväl friska råttor som i en djurmodell av Parkinsons sjukdom, eftersom patienter med denna motorsjukdom drabbas av särskild stora svårigheter att initiera och utföra rörelser. Utöver detta får många Parkinsonpatienter även problem med biverkningar av sin medicinering i form av ofrivilliga rörelser. I samband med dessa ofrivilliga rörelser har vår grupp kunnat påvisa ett nytt resonansfenomen i en viss del av hjärnans motorsystem, vilket bland annat är något som vi nu ämnar undersöka i närmare detalj. I detta lunchseminarium kommer jag ge en överblick över vår forskning och använda det som en utgångspunkt för att ta upp några av de relaterade tekniska utmaningar inom experimentell och teoretisk neurovetenskap, såsom design av neurala gränssnitt för både inspelning och stimulering, metoder för signal- och bildbehandling, samt modellering av hjärnsignaler.
PhD thesis defence Marius Cismasu
Date: 2014-10-27, at 10:15
Place: Lecture hall E:1406, E-building, Ole Römers väg 3, Lund University Faculty of Engineering
Opponent: Professor Anja Skrivervik. École polytechnique fédérale de Lausanne, Switzerland
Antenna Analysis and Design Using Stored Energies and Physical Limitations
ISSN ISSN 1654-790X; No. 65, 2014.
Abstract: A method to estimate Q and QZ' of antennas from single-frequency current distributions is described. This single-frequency method and the concepts of physical bounds on antenna parameters and optimum current distributions are applied to different analysis and design situations of two-dimensional and three-dimensional radiating structures (i.e., antennas). The situations considered are: antenna optimization using a genetic algorithm and the single-frequency Q computation for single or multi-band operation, antenna placement optimization in a wireless device using physical bounds, and antenna optimization that includes QZ' in the objective function. Antenna performance is compared with physical bounds or optimum-current performance in the situations studied.
The results presented in this thesis suggest that single-frequency methods may reduce the time necessary to optimize automatically, e.g., using a computer, some antenna parameters such as bandwidth. Furthermore, physical bounds and optimum current distributions are tools that provide valuable information for the processes of antenna analysis and design.
ELLIIT Workshop 2014
ELLIIT Workshop 2014
Date: Oct 23-24, 2014
Place: K1 Lecture Hall (Campus Norrköping) Bredgatan 33
Master Thesis Presentation on Localization
Date: Thursday October 23
Ji Wang will present his Master's thesis "Modeling and Implementation of All-Digital Phase-Locked Loop Based on Vernier Gated Ring Oscillator Time-to-Digital Converter", performed under the supervision of post-doc fellow Ping Lu.
In this thesis, a complete design of an All-Digital Phase-Locked Loop (ADPLL) for RF application is presented. A Vernier gated ring oscillator time-to-digital converter (TDC) is utilized in the proposed ADPLL, and a two-dimension architecture is developed for the TDC to improve latency and dynamic range. The proposed TDC is able to achieve a raw resolution of 5 ps while provides a detection range up to 10 ns. Meanwhile, an LC tank based digitally controlled oscillator (DCO) with three tuning banks is employed to realize fast frequency tuning and fine resolution of 4 KHz. The simulation on the presented ADPLL predicts an output frequency ranging from 3 GHz to 6 GHz with a reference input of 50 MHz.
Tid: 22 Oktober 2014, kl 9-16 Plats: E:1406 Kursen Kommunikationssystem inom civilingenjörsutbildningen i Informations- och kommunikationsteknik innehåller ett större fördjupningsprojekt. Studenterna lär sig mer om dagens och framtidens system för tele- och datakommunikation samt hur man rapporterar och presenterar sitt arbete i konferensmiljö. Konferensen är ett obligatoriskt inslag i kursen och ger en introduktion och försmak av det akademiska arbetssättet. 52 studenter, varav 10 kvinnliga, är antagna till årets program och till kursen. Keynote: Sven Mattisson, Adjungerad professor. Presentationer: -IEEE 802.11 - Hur säkert är det? -Ad Hoc & Sensornätverk - Hälsotillämpningar -Anonymitet med Tor -Cloud Computing - En himmelsk lösning? -Green Networking - energieffektivisering av nätverk -Delay Tolerant Networks -LTE - framtidens mobiltelefoni idag -PON - Fiberns utveckling -RFID - säkerhet & integritet -SDN - En oslipad diamant -VANET - IEEE 802.11p -De Virtuella Valutornas Värld -Bitcoin, så funkar det Konferensen sponsras av Sony Mobile, Network Services, Patwic, Anritsu och C-programmet vid LTH.
EIT-talks at Mobile Heights Center Grand Opening
Date: October 21, 2014
Place:< Mobile Heights Center, Lund
The following LTH-EIT research presentations on world-class research topics will take place at Vasakronan Mobile Heights Center (MHC) Grand Opening Oct 21, 2014. The inauguration of MHC will be attended by Fredrik Wirdenius, Vasakronan CEO and Pia Kinhult, First Governor of Skåne and Mats Helmfrid, Mayor of Lund. Key note by international guest and startup incubator guru Ken Thom. To see more on the full program, go to
EIT-presentations will cover:
13.30-13.50 "The need to reconsider WLAN access schemes, beyond CSMA." Emma Fitzgerald LTH-EIT
13.50-14.10 "Content management in a world of user generated content, efficient cacheing and replication strategies", Saeed Bastani LTH-EIT
14.10-14.30 "Wireless Connectivity for ultra-portable devices and Internet of Things", Henrik Sjöland LTH-EIT
14.30-14.50 "Low-power design in the IoT-perspective", Joachim Rodrigues LTH-EIT
14.50-15.10 "Challenges in Test and Reliability” Dimitar Nikolov LTH-EIT>
15.10-15.30 "Mobile Communications going Massive", Ove Edfors LTH-EIT
15.30-15.50 "mm-Wave technology and 5G", Daniel Sjöberg LTH-EIT
Seat reservations can be made at
PhD thesis defence Reza Meraji
Date: 2014-10-17, at 10:15
Place: Lecture hall E:1406, Department of Electrical and Information Technology, Ole Römers väg 3, Lund University Faculty of Engineering
Opponent: Associate Professor Chris Winstead. Utah State University, USA
Low Power Decoding Circuits for Ultra Portable Devices
ISSN 1654-790X; No. 64, 2014.
Abstract: A wide spread of existing and emerging battery driven wireless devices do not necessarily demand high data rates. Rather, ultra low power, portability and low cost are the most desired characteristics. Examples of such applications are wireless sensor networks (WSN), body area networks (BAN), and a variety of medical implants and health-care aids. Being small, cheap and low power for the individual transceiver nodes, let those to be used in abundance in remote places, where access for maintenance or recharging the battery is
limited. In such scenarios, the lifetime of the battery, in most cases, determines the lifetime of the individual nodes. Therefore, energy consumption has to be so low that the nodes remain operational for an extended period of time, even up to a few years. It is known that using error correcting codes (ECC) in a wireless link can potentially help to reduce the transmit power considerably. However, the power consumption of the coding-decoding hardware itself is critical in an ultra low power transceiver node. Power and silicon
area overhead of coding-decoding circuitry needs to be kept at a minimum in the total energy and cost budget of the transceiver node. In this thesis, low power approaches in decoding circuits in the framework of the mentioned applications and use cases are investigated. The presented work is based on the 65nm CMOS technology and is structured in four parts as follows:
In the first part, goals and objectives, background theory and fundamentals of the presented work is introduced. Also, the ECC block in coordination with its surrounding environment, a low power receiver chain, is presented. Designing and implementing an ultra low power and low cost wireless transceiver node introduces challenges that requires special considerations at various levels of abstraction. Similarly, a competitive solution often
occurs after a conclusive design space exploration. The proposed decoder circuits in the following parts are designed to be embedded in the low power receiver chain, that is introduced in the first part.
Second part, explores analog decoding method and its capabilities to be embedded in a compact and low power transceiver node. Analog decod-
ing method has been theoretically introduced over a decade ago that followed with early proof of concept circuits that promised it to be a feasible low power solution. Still, with the increased popularity of low power sensor networks, it has not been clear how an analog decoding approach performs in terms of power, silicon area, data rate and integrity of calculations in recent technologies and for low data rates. Ultra low power budget, small size requirement
and more relaxed demands on data rates suggests a decoding circuit with limited complexity. Therefore, the four-state (7,5) codes are considered for hardware implementation. Simulations to chose the critical design factors are presented. Consequently, to evaluate critical specifications of the decoding circuit, three versions of analog decoding circuit with different transistor
dimensions fabricated. The measurements results reveal different trade-off possibilities as well as the potentials and limitations of the analog decoding approach for the target applications. Measurements seem to be crucial, since the available computer-aided design (CAD) tools provide limited assistance and precision, given the amount of calculations and parameters that has to be included in the simulations. The largest analog decoding core (AD1) takes
0.104mm2 on silicon and the other two (AD2 and AD3) take 0.035mm2 and
0.015mm2, respectively. Consequently, coding gain in trade-off with silicon area and throughput is presented. The analog decoders operate with 0.8V supply. The achieved coding gain is 2.3 dB at bit error rates (BER)=0.001 and 10 pico-Joules per bit (pJ/b) energy efficiency is reached at 2 Mbps.
Third part of this thesis, proposes an alternative low power digital decoding approach for the same codes. The desired compact and low power goal has been pursued by designing an equivalent digital decoding circuit that is fabricated in 65nm CMOS technology and operates in low voltage (near-threshold) region. The architecture of the design is optimized in system and circuit levels to propose a competitive digital alternative. Similarly, critical specifications of the decoder in terms of power, area, data rate (speed) and
integrity are reported according to the measurements. The digital implementation with 0.11mm2 area, consumes minimum energy at 0.32V supply which gives 9 pJ/b energy efficiency at 125 kb/s and 2.9 dB coding gain at BER=0.001.
The forth and last part, compares the proposed design alternatives based on the fabricated chips and the results attained from the measurements to conclude the most suitable solution for the considered target applications.
Advantages and disadvantages of both approaches are discussed. Possible extensions of this work is introduced as future work.
Seminar by Chris Winstead
Date: October 16, 1.15 pm Location: E:2311 Title: "Noise enhanced LDPC decoding" Welcome to the seminar "Noise enhanced LDPC decoding" by Associate Professor Chris Winstead from Utah State University. Chris will also be the faculty opponent during the disputation of Reza Meraji on October 17. Abstract: Recent results are presented for a highly efficient error correction algorithm known as Noisy Gradient Descent Bit Flipping (NGDBF). This algorithm drastically improves on a previously known method by injecting artificial "noise" into the operations, in effect "fighting noise with noise" (to borrow a phrase from Prof. David Declerq, ENSEA, France). Our new algorithm is applicable to Low-Density Parity Check (LDPC) codes, which are a key part of many high-performance communication standards. LDPC decoders typically employ advanced signal processing algorithms that are able to approach the theoretical Shannon limit in performance. These advanced algorithms, however, require resource-intensive implementations that lead to high power consumption and large silicon area, making them unsuitable for some applications. An alternative family of algorithms, collectively termed "bit-flipping" methods, perform decoding by exchanging single-bit messages, which gives them very low complexity. Although bit-flipping algorithms have been known for some time, they have had limited application due to their comparatively poor performance. Our latest results show that NGDBF can come very close to the best commercial algorithms on important standards, such as IEEE 802.3 (10GBase-T). A tutorial introduction to the algorithm will be presented, along with a plausible implementation architecture, an analysis of the algorithm's theoretical characteristics, and a discussion of open problems. Biography: Chris Winstead received the B.S. degree in Electrical and Computer Engineering from the University of Utah in 2000, and the Ph.D. degree from the University of Alberta in 2005. He is currently with the ECE Department at Utah State University, where he holds the rank of Associate Professor. Dr. Winstead's research interests include reliable wireless communication systems, implementation of error-correction algorithms, low-power electronics and fault-tolerant VLSI circuits. In 2010, Dr. Winstead received the NSF Career award for research in low-energy wireless communication circuits. During 2013-2014, he was a Fulbright Visiting Professor at the Universite de Bretagne Sud (UBS) in Lorient, France. He is also a Senior Member of the IEEE and a member of the Tau Beta Pi engineering honor society.
Master Thesis Presentation on Localization
Monday Sept 29 Xiao Hu and Chengqi Ma will present their master’s thesis “Wi-Fi based Localization of Cell Phones” at 13.15 in E3139. You are all welcome to attend.
IoT Master Thesis Presentation
Adam Johansson will present his master thesis on Friday Sept 26th at 10:15 in E:3139
EIT at MIT! Don't miss todays event at 3.15, 1406!
MIT at EIT!!! Today we have the pleasure to host yet one of the leading scientists in Lund, this time from MIT. Prof. del Alamo will serve as faculty opponent for Sofia and he will also give a seminar on status of III-V MOSFETs. Prof. del Alamo is editor for IEEE Electron Device Letters, Fellow IEEE, and Director for Microsystems Technology Laboratories at MIT. He is one of the key scientists in the rapid development of III-V MOSFETs. The seminar will be in E: 1406 at 3.15 pm. Don't miss this opportunity to listen to one of the top-scientists at MIT! Most welcome!
PhD thesis defence Sofia Johansson
Date: 2014-09-25, at 13:15
Place: Lecture hall E:1406, E-building, Ole Römers väg 3, Lund University Faculty of Engineering
Opponent: Jesús del Alamo. Massachusetts Institute of Technology, USA
Vertical Nanowire High-Frequency Transistors
ISSN 1654-790X, No. 61, 2014.
Abstract: This thesis explores a novel transistor technology based on vertical InAs nanowires, which could be considered both for low-power high-frequency analog applications and for replacing Si CMOS in the continued scaling of digital electronics. The potential of this device - the vertical InAs nanowire MOSFET ? lies in the combination of the outstanding transport properties of InAs and the improved electrostatic control of the gate-all-around geometry.
Three generations of the vertical InAs nanowire MOSFET are presented in this thesis; the first generation, integrated on semi-insulating InP substrate, provided the first RF measurements on vertical nanowire transistors with extrinsic ft/fmax > 7/20 GHz. Utilizing the resilience towards dislocations inherent to the vertical nanowire growth, the second generation is integrated on highly resistive Si substrates by a thin InAs buffer layer. The RF performance is comparable to the first generation, indicating sustained crystal quality of the nanowires. In the third generation, however, a great boost in the RF performance is achieved by removing excess metal overlap and, hence, reducing the parasitic gate capacitance, which resulted in extrinsic ft/fmax = 141/155 GHz at Lg ? 150 nm.
The main challenge for III-V MOSFETs is the high-? integration as high densities of charge traps deteriorate the device performance. Focusing on the border traps, a method based on frequency dispersion in gm (1 Hz-100 GHz) is developed for direct measurement of the trap density as a function of distance from the oxide-semiconductor interface. The method is demonstrated for vertical InAs nanowire MOSFETs and surface-channel InGaAs MOSFETs.
2014-09-19 Seminar by Prof. Shanthi Pavan
On Friday 19 September, at 9.15-12.00, in room E:3139, Prof. Shanthi Pavan from the Indian Institute of Technology of Madras, India (who will be the faculty opponent in Dejan Radjen's PhD defense on September 18) will deliver two extremely interesting lectures on Delta-Sigma modulators, whose abstract you can read below.
Shanti Pavan (Photo: IIT Madras)
He will also add in some discussion on the most recent Delta-Sigma designs from his research group. After the seminar, Prof. Pavan will be happy to answer your questions and clarify your doubts.
Prof. Pavan is a very well-known researcher world-wide (he is Editor-in-Chief for the prestigious IEEE Transactions on Circuits and Systems: Regular Papers, as well as a TPC member of the IEEE ISSCC), and has produced some of the most original and best performing Delta-Sigma modulators to date. We can mention that he has been the co-recipient of the Silkroad Award at ISSCC 2012 (for outstanding paper from the Far East Region) and of the Best Student Paper Award at ISCAS 2013.
Continuous-time Delta Sigma Modulator Design: The Method of Moments Approach
The design of a CTDSM typically involves back and forthing between the s-and-z domains. In this talk, I will show that the Noise Transfer Function (NTF) of a practical CTDSM only depends on the area and delay of the DAC pulse. All other details of the pulse shape are irrelevant! This observation is made possible by examining the CTDSM using the method of moments. Apart from yielding new insights into modulator operation, this also simplifies the process of compensating for excess loop delay for arbitrary DAC pulses. Design examples illustrating the technique will be given.
A Continuous-time Delta Sigma Modulator as a Time Varying System
A Continuous-time Delta Sigma Modulator has implicit anti-aliasing - this is a commonly heard refrain in the data converter community. It turns out that this only correct under some assumptions, which are not satisfied in many designs. In this talk, I will view a CTDSM as a linear periodically time varying system. This yields new insights into CTDSM operation - the Signal Transfer Function (STF), thermal noise and techniques that can be used to simulate these quantities.
PhD thesis defence Dejan Radjen
Date: 2014-09-18, at 10:15
Place: Lecture hall E:1406, Department of Electrical and Information Technology, Ole Römers väg 3, Lund University Faculty of Engineering
Opponent: Shanti Pavan. Indian Institute of Technology, Madras, India
Continuous-Time Delta-Sigma Modulators for Ultra-Low-Power Radios
ISSN 1654-790X; No. 62, Department of Electrical and Information Technology, Lund University, 2014.
Abstract: The modern small devices of today require cheap low power radio frequency (RF) transceivers that can provide reliable connectivity at all times. In an RF transceiver, the analog-to-digital converter (ADC) is one of the most important parts and it is also one of the main power consumers. There are several architectures for implementing an ADC, but in the last decade, continuous-time Delta-Sigma modulators (CT DSMs) have become popular due to their potential of achieving low power consumption and the inherent anti-alias filtering.
This thesis investigates different implementations of CT DSMs intended for an ultra-low-power (ULP) receiver operating in the 2.45 GHz ISM band. The main focus is on power saving techniques and jitter insensitive solutions. Papers I and II present a CT DSM with dual switched-capacitor-resistor (DSCR) feedback used in the first DAC. This technique has been developed for the purpose of reducing the jitter sensitivity of the CT DSM while keeping the DAC peak current lower than for conventional SCR feedback. A lower peak current translates into more relaxed slew-rate requirements on the first operational amplifier and thereby less power consumption. Papers III and IV present a low power 2nd-order CT DSM with one operational amplifier. The main objective was to reduce the power consumption of the usually more critical analog part while still achieving a 2nd-order noise shaping. The thesis also examines the possibility of using a successive approximation register (SAR) quantizer instead of the commonly used flash quantizer to reduce the power consumption of the digital part as well.
2014-09-11 Lund Circuit Design Workshop
The workshop takes place at Lund University in Lund, Sweden, September 11-12, 2014. The venue is Grand Hotel (Day 1) and the Faculty of Engineering (Day 2) and the workshop will offer an overview of the IC design research activities at Lund University. Information from previous workshops to be found at Previous CD-Workshops
PhD thesis defence Meifang Zhu
Date: 2014-09-12, at 13:15
Place: Lecture hall E: 1406, Department of Electrical and Information Technology, E-building, John Erikssons väg 4, Lund University Faculty of Engineering
Opponent: Vittorio Degli-Esposti. University of Bologna, Italy
Geometry-based Radio Channel Characterization and Modeling: Parameterization, Implementation and Validation
ISSN 1654-790X No. 63, 2014.
Abstract: The propagation channel determines the fundamental basis of wireless communications, as well as the actual performance of practical systems. Therefore, having good channel models is a prerequisite for developing the next generation wireless systems. This thesis first investigates one of the main channel model building blocks, namely clusters. To understand the concept of clusters and channel characterization precisely, a measurement based ray launching tool has been implemented (Paper I). Clusters and their physical interpretation are studied by using the implemented ray launching tool (Paper II). Also, this thesis studies the COST 2100 channel model, which is a geometry-based channel model using the concept of clusters. A complete parameter set for the outdoor sub-urban scenario is extracted and validated for the COST 2100 channel model (Paper III). This thesis offers valuable insights on multi-link channel modeling, where it will be widely used in the next generation wireless systems (Paper IV and Paper V). In addition, positioning and localization by using the phase information of multi-path components, which are estimated and tracked from the radio channels, are investigated in this thesis (Paper VI).
Clusters are extensively used in geometry-based stochastic channel models, such as the COST 2100 and WINNER II channel models. In order to gain a better understanding of the properties of clusters, thus the characteristics of wireless channels, a measurement based ray launching tool has been implemented for outdoor scenarios in Paper I. With this ray launching tool, we visualize the most likely propagation paths together with the measured channel and a detail floor plan of the measured environment. The measurement based ray launching tool offers valuable insights of the interacting physical scatterers of the propagation paths and provides a good interpretation of propagation paths. It shows significant advantages for further channel analysis and modeling, e.g., multi-link channel modeling.
\par The properties of clusters depend on how clusters are identified. Generally speaking, there are two kinds of clusters: parameter based clusters are characterized with the parameters of the associated multi-path components; physical clusters are determined based on the interacting physical scatterers of the multi-path components. It is still an open issue on how the physical clusters behave compared to the parameter based clusters and therefore we analyze this in more detail in Paper II. In addition, based on the concept of physical clusters, we extract modeling parameters for the COST 2100 channel model with sub-urban and urban micro-cell measurements. Further, we validate these parameters with the current COST 2100 channel model MATLAB implementation.
The COST 2100 channel model is one of the best candidates for the next generation wireless systems. Researchers have made efforts to extract the parameters in an indoor scenario, but the parameterization of outdoor scenarios is missing. Paper III fills this blank, where, first, cluster parameters and cluster time-variant properties are obtained from the 300~MHz measurements by using a joint clustering and tracking algorithm. Parameterization of the COST 2100 channel model for single-link outdoor MIMO communication at 300~MHz is conducted in Paper III. In addition, validation of the channel model is performed for the considered scenario by comparing simulated and measured delay spreads, spatial correlations, singular value distributions and antenna correlations.
Channel modeling for multi-link MIMO systems plays an important role for the developing of the next generation wireless systems. In general, it is essential to capture the correlations between multi-link as well as their correlation statistics. In Paper IV, correlation between large-scale parameters for a macro cell scenario at 2.6 GHz has been analyzed. It has been found that the parameters of different links can be correlated even if the base stations are far away from each other. When both base stations were in the same direction compared to the movement, the large-scale parameters of the different links had a tendency to be positively correlated, but slightly negatively correlated when the base stations were located in different directions compared to the movement of the mobile terminal. Paper IV focuses more on multi-site investigations, and paper V gives valuable insights for multi-user scenarios. In the COST 2100 channel model, common clusters are proposed for multi-link channel modeling. Therefore, shared scatterers among the different links are investigated in paper V, which reflects the physical existence of common clusters. We observe that, as the MS separation distance is increasing, the number of common clusters is decreasing and the cross-correlation between multiple links is decreasing as well. Multi-link MIMO simulations are also performed using the COST 2100 channel model and the parameters of the extracted common clusters are detailed in paper V. It has been demonstrated that the common clusters can represent multi-link properties well with respect to inter-link correlation and sum rate capacity.
Positioning has attracted a lot of attention both in the industry and academia during the past decades. In Paper VI, positioning with accuracy down to centimeters has been demonstrated, where the phase information of multi-path components from the measured channels is used. First of all, an extended Kalman filter is implemented to process the channel data, and the phases of a number of MPCs are tracked. The tracked phases are converted into relative distance measures. Position estimates are obtained with a method based on so called structure-of-motion. In Paper VI, circular movements have been successfully tracked with a root-mean-square error around 4 cm when using a bandwidth of 40 MHz. It has been demonstrated that phase based positioning is a promising technique for positioning with accuracy down to centimeters when using a standard cellular bandwidth.
In summary, this thesis has made efforts for the implementation of the COST 2100 channel model, including providing model parameters and validating such parameters, investigating multi-link channel properties, and suggesting implementations of the channel model. The thesis also has made contributions to the tools and algorithms that can be used for general channel characterizations, i.e., clustering algorithm, ray launching tool, EKF algorithm. In addition, this thesis work is the first to propose a practical positioning method by utilizing the distance estimated from the phases of the tracked multi-path components and showed a preliminary and promising result.
Ex-jobbspresentation: Adeel Muhammad Hashmi
On Wednesday September 10, at 14.15 in E:2349, Adeel Muhammad Hashmi will present his Master’s thesis “Parabolic Synthesis and Non-Linear Interpolation”
You are all Welcome!
Computation and implementation of unary functions such as trigonometric, logarithmic and exponential function have a vital importance in modern applications, e.g., Digital Signal Processing, computer graphics, wireless systems and virtual reality simulations. Over the past few years many software solutions have been used, which provide extreme precision but take a lot of computation time for real-time applications. As compared to the software routines, a hardware implementation of unary function is found to be a best solution for real-time applications where fast and numerically intensive solutions are required.
This thesis work presents an approximation of trigonometric functions, i.e. Sine and Cosine using Parabolic Synthesis combined with Non-Linear Interpolation. The architecture for the approximation is designed and implemented in the stm65 CMOS technology. There is a high degree of parallelism in the design which makes it faster than other methodologies to calculate unary functions. The same design can be used to implement various kinds of unary function like logarithmic and exponential etc with the same architecture.
The design is compared, with respect to power consumption, area and maximum speed, with the existing methodologies like CORDIC, Parabolic Synthesis, and Parabolic Synthesis with Linear Interpolation. It is found that the architecture has better performance in terms of chip area, speed and power consumption.
2014-06-25 Ex-jobbspresentation: Martin Andersson och Johan Kjörnsberg
On Wednesday 25 June, at 14.15, in room E:2311, Martin Andersson and Johan Kjörnsberg will present their
Master Thesis titled “Design of LIDAR System”
The project has been performed in cooperation with Axis, supervised by Carl-Axel Alm and Anders Nejdel.
You are most welcome to attend the presentation!
In this Master Thesis project a Laser Range Finder suitable for implementation in a LIDAR system has been designed. The device architecture is based on measuring the phase difference between a transmitted laser signal and diffusely reflected light from the target, using an IQ-demodulator. The measured performance is a range of 27 m with a standard deviation of 7.4 cm with an estimated measurement speed of 8000 measurement points per second.
All parts of the system have been investigated, from transmitting and receiving circuits to the optical system. A study on Laser eye safety has been performed. The system has been implemented on PCB:s designed during this project.
2014-06-25 Ex-jobbspresentation: Niklas Hjern och Jonas Vistrand
On Wednesday, June 25, Niklas Hjern and Jonas Vistrand will present their Master’s Thesis “Authorization for Industrial Control Systems”.
The work has been done at ABB and also in cooperation with SICS. The presentation will start at 10.15 in E:3139.
You are all welcome!
Every day more and more devices are getting connected to the Internet, a phenomenon commonly referred to as the Internet of Things. Since security and privacy are more important than ever before this presents an interesting problem. Suddenly devices with not even near as much computing power as a desktop computer are tasked with performing heavy security computations designed to be used in powerful systems with little resource and power limitations. This thesis presents a solution for performing authorization for a resource limited system using a trusted third party, thus transferring the usually quite heavy authorization computations from a resource constrained device to another device where no such restrictions exists. When a client wishes to request a resource on the constrained device it must first retrieve authorization information from the third party and include this in the request. The authorization information is then validated by confirming that it originates from the trusted third party using a shared secret. In this thesis the constrained system is represented by an ABB control system of model 800xA and by transferring the authorization cost to another system the increased amount of resource usage on this device is kept to a minimum. It is also shown that this increase is negligible compared to the increase in resource usage when authentication and message protection in the form of TLS was implemented.
2014-06-23 Ex-jobbspresentation: Shubo Yan
On Monday 23 June, at 15.15, in room E:2311 Shubo Yan will present his Master Thesis titled
"Time Domain Electromagnetic (EM) Simulations for IC Packages Modeling"
You are most welcome to attend the presentation!
Because the duration of charged device model (CDM) events is short, CDM-induced damage most often manifests as oxide breakdown. The high current density exists during an electrostatic discharge (ESD) event can cause thermal damage and induce voltages sufficient to damage gate oxides. Effective protection against ESD is critical for high yield and reliability of ICs. It is necessary to study the discharge path to improve the CDM robustness. In this thesis, an accurate and simple model of IC packages under electrostatic discharge (ESD) charged device model (CDM) was presented for the circumstances of using new type of electromagnetic simulations.
To understand the discharge phenomenon and strengthen the protection designs, the accurate and efficient CDM discharge simulation has become very important. Here, the electromagnetic professional (EMPro®) software is adopted in this study. The 3D model of LQFP64 IC package was established and optimized in the EMPro® simulation environment. Then, the LQFP64 package of ICs was also characterized in the actual measurements, i.e. time domain reflectometry (TDR) is applied to extract the parasitics. The simulation model had been updated based on the experimental testing results. And the comparison between the EMPro® simulation results and the testings had been conducted completely. There is a good agreement between the simulation and tested results.
In summary, the feasibility of using the 3D simulation model of IC package based on the EMPro® software was presented in this thesis for LQFP64. Then the parasitics of the LQFP64 package for the lumped elements model are extracted through using the TDR measurement. So the lumped elements parameters of a typical PUT extracted from TDR measurements of the IC packages are obtained. Finally, the extracted lumped circuit is integrated into the model and used to simulate the CDM discharge and compare to actual CDM discharge waveforms measured from these IC packages.
2014-06-19 Ex-jobbspresentation: Daniel Hilton
Välkommen till Daniel Hiltons exjobbspresentation:
Titel: 'Variability modeling in automotive embedded systems'
Tid: Torsdag 19 Juni 2014 kl 10:15
Examinator: Erik Larsson
To satisfy the needs of the highly competitive and customer oriented automotive market most manufacturers target the specific needs of their prospective customers by creating a highly flexible product line. Over the past two decades the complexity of automotive vehicles has grown rapidly . As vehicle functionality has increased, so has the amount of possible configurations that a vehicle can have. This is handled by introducing variation points in the embedded software in order to adapt its use to the different configurations. However this introduction is often given incidental treatment by developers which leads the system architecture becoming increasingly inconsistent and highly complex over time. As a consequence of this the impact of a vehicle configuration becomes extremely time-consuming and hard to evaluate. To be able to meet the increasing demands on functional safety in the automotive embedded systems the impact of this variability must be known and evaluated. This thesis aims to explore the possibility of recovering a model which describes the software variability within Scania’s embedded systems. The method that is used involves the definition of a model through using the information and data that is retrieved from the process of architecture recovery. This results in a model that provides an architectural overview of where the vehicle configuration choices affect the embedded systems within Scania. The conclusion is that although the recovered model provides information about the variability there are large limitations when recovering variability from legacy systems through architecture recovery.
2014-06-16 Ex-jobbspresentation: Patrik Billgren
On Monday, June 16, Patrik Billgren will present his master’s thesis “Analysis of Defenses Against Return Oriented Programming”. The presentation will start at 13.15 in E3139.
You are all welcome.
Return Oriented Programming is a security exploit technique which builds on code-reuse from program libraries. Over seventeen different protections against this attack are available, which are in need of being analyzed, categorized and compared. The protections are thoroughly compared, a couple of them are implemented and tested, and new design ideas are explored.
A new protection design ORPScan is presented, which combines the strengths of two different techniques, In Place Randomization and Input Scanning. ORPScan can be used to detect Return Oriented Programming attacks without any false positives.
2014-06-13 Ex-jobbspresentation: Magnus Altgård och Annica Eriksson
On Friday 13/6, Magnus Altgård and Annica Eriksson will present their MSc thesis “Energy Harvesting in Wireless Sensor Networks“ performed at Verisure AB. The presentation is in E:2311 and starts at 10.15.
Everyone is most welcome!
This thesis evaluates the concept of Energy Harvesting as a power source for a Wireless Sensor Node. Included is a background study of possible energy harvesters and relevant electronics, design of a physical proof of concept and performance measurements of the design. A wireless sensor node with a minimum power consumption of 1 mW was designed as a proof of concept. The design utilizes an ARM Cortex M0+ microcontroller and relevant software together with a self-developed radio protocol.
2014-06-11 Ex-jobbspresentation: Jakob Helander
Jakob Helander will present his master thesis
“mmWave Antenna Technology in Mobile Terminal and Station”
on Wednesday 11 June, 14.15 in E:2349.
The thesis has been performed in collaboration with Sony Mobile. The supervisors have been Daniel Sjöberg (EIT) and Zhinong Ying (Sony), and the examiner is Mats Gustafsson. The abstract is given below.
In this thesis, mmWave antennas have been investigated for future cellular communication systems. The new generation of wireless devices have led to a rapid increase in total mobile data traffic. The usage of smart phones and tablets require the support of high quality multimedia applications, and as the capacity demands will continue to increase as technology advances, the necessity of higher data rates cannot be ignored. Using more bandwidth directly translates into higher data rates, and as today’s cellular bands are restricted to carrier frequencies between ∼ 800 MHz and ∼ 2.6 GHz where the channel bandwidths are relatively narrow (∼ 20 MHz), a potential solution is to use higher frequencies were the wider bandwidths available can be exploited.
However, moving up to mmWave frequencies indicates an increase of propagation losses as the operational wavelength decreases significantly. A potential solution is to use higher gain antennas in the mobile station compared to today’s standards. The high gain results in a narrower beam, and to always be able to establish a good link it then becomes necessary to use steerable antennas. Thus phased arrays can be used, where input phase shift variations can be applied to steer the narrow beam in a desired direction. It is therefore of great interest to investigate the total scan pattern of such a system, and evaluate this pattern in terms of how large coverage is obtainable.
The thesis work includes a study of recent advancements in mmWave technology, to motivate a choice of antenna types for usage in mobile stations. This study aims at pointing out the state of the art of the current research front regarding mmWave antennas.
Three different designs have been chosen, modeled in CST and evaluated with respect to target gain, radiation efficiency, bandwidth, radiation characteristics and footprint. The target operational frequencies are set to 15 GHz and 28 GHz. The single element models have then been used to construct the phased array designs. Different diversity combinations have been tested to validate what configurations show most promise in terms of achievable coverage efficiency. The efficiency is calculated for different values of minimum received gain. The aim of this part is to illustrate the viability of evaluating mobile station antennas in terms of coverage efficiency, as the total scanning pattern is a fundamental parameter to consider. The study have investigated initial designs of a patch, dielectric resonator antenna (DRA) and an open-ended substrate integrated waveguide (SIW) for mmWave operation in mobile terminal. The DRA shows good promise in bandwidth and radiation efficiency, however its broadside radiation characteristics makes the achievable coverage dependent on the spatial degrees of freedom for implementation. The study indicates that edge radiating elements show good promises in terms of achievable coverage. The study have contributed to the evaluation of the total scan pattern of phased array systems in terms of coverage efficiency.
2014-06-10 Ex-jobbspresentation: Farnaz Chaman-Zadeh
Farnaz Chaman-Zadeh will present her masters thesis
"Feeding of Characteristic Modes in Multi-antenna Mobile Handsets"
on Tuesday, June 10th, between 13:15 and 14:00 in E:2311.
We hope you are able to attend,
Multiple input multiple output (MIMO) antenna systems fundamentally require the radiation patterns of the antennas to be nearly orthogonal to one another. In a multipath environment, the orthogonality of the patterns allows for increased throughput, link reliability and coverage. The requirement of orthogonal antenna patterns is difficult to realize at low mobile frequency bands due to the small sizes of modern mobile handsets. In this work, several MIMO terminal antenna systems operating at Long Term Evolution (LTE) bands below 1 GHz were analyzed using the Theory of Characteristic Modes (TCM). This analysis technique reveals all the orthogonal patterns that a structure is physically able to produce. Through a combination of one or more orthogonal modes, found through TCM analysis, any physically obtainable pattern can be produced. TCM is able to provide currents, near-fields, and far-fields for each orthogonal mode. These modal currents and fields were correlated to those of real antennas structures excited traditionally in CST simulation. The results provide valuable insight into the modes excited in many common modern mobile phone antennas and the underlying mechanisms for some antenna structures to outperform others of the same size and shape.
2014-06-09 Ex-jobbspresentation: Manuel Bejarano Carmona
Manuel Bejarano Carmona will present his Master thesis work on June 9th (Monday) at 10:15 in E:3139
Thesis title: Design of a SiGe Power Amplifier for the 81-86 GHz E-band
This thesis presents the design of a two-stage differential cascode Power Amplifier for 81-86 GHz E-Band applications. Two stacked 1-to-1 transformers are used for power combining and single-ended to differential conversion. According to EM simulations, input and output transformers show an insertion loss of -0.63 dB and -0.45 dB respectively. The PA was realized in SiGe technology using Infineon B7HF200 0.18um SiGe HBT process with fT/fmax 200/250 GHz. An inter-stage matching network consisting of a LC-match was used in the interface between input and output stage. Although the design has been taped-out, the results presented are based on post-layout simulations as the chip has not arrived on time for publication. The PA delivers 18 dBm saturated output power and exhibits a gain of 15.7 dB at 83.5 GHz when operated from a 3.5 V DC supply, reaching 10.1% peak PAE. The complete design occupies an area of 0.026 mm^2.
2014-06-09 Ex-jobbspresentation: Anna Johansson
On Monday, 9:th of June, Anna Johansson will present her master thesis entitled “Application based adaptive sound enhancement for loudspeakers”. The work has been done at Orlo.
Time: 9:th of June, 13:15
You are all welcome to attend.
This master thesis presents a system for adaptive enhancement of music to com- pensate for disturbances introduced by the environment and imperfections in the equipment, and additional sound effects to create an optimal sound. A method is presented to estimate the frequency response of the listening environment and the loudspeaker, and to compensate for these unwanted changes of the music from the source to the listener. Tests are made to demonstrate the effects of different loudspeakers and room environments including distortion measurements, and to show that the proposed method can eliminate these effects. The results show that the method is capable to eliminating the unwanted changes to within 1 dB of the original signal which increases both the perceived quality, and the consistency of the quality of the original music signal. This thesis shows that this kind of sound enhancement is possible to realize, using an adaptive system for calibration and modification of the signal to desired sound.
2014-06-03 Seminarie/Demonstration: Ivaylo Vasilev och Jonas Lindstrand
As a conclusion to the Antenna-Channel Harmonization for Throughput Enhancement in Advanced Mobile Terminals project we invite you to a seminar / demonstration (30 min + questions).
Title: Adaptive Impedance Matching Demo Presentation
Speakers: Ivaylo Vasilev and Jonas Lindstrand, EIT, Lund University
Time/place: 13.15 - 14.15 on Tuesday June 3rd in E:2311
You are all very welcome!
Ivaylo Vasilev and Jonas Lindstrand
Absorption and impedance mismatch due to user proximity are well known to severely degrade multiple-input-multiple-output (MIMO) performance of multi-antenna terminals in real usage scenarios. In this context, we investigated the potential of adaptive impedance matching (AIM) to mitigate such performance degradations. A system consisting of custom designed 130nm CMOS-SOI impedance tuners, MIMO terminal antenna and LabView demonstration software is used to evaluate the practical applicability of AIM in real-life communication systems. Based on channel measurements involving a real test subject and the antenna / impedance tuner prototype we demonstrate channel capacity gain of 34% and equivalent power gain of 4 dB as compared to a standard 50Ω termination. Taking into consideration the resistive loss and mismatch loss associated with the impedance tuners the total equivalent power gain is up to 2 dB. At the seminar we will introduce the system setup, tuner circuits, terminal antenna as well as the LabView evaluation software developed to demonstrate real-life performance. Further, we will show a demonstration video where the performance enhancements will be presented in real-time.
This project is a result of the collaboration between Lund University, VINNOVA, Sony Mobile Communications AB and the companies within the SoS (System Design on Silicon) center.
2014-05-28 Seminarie: Walter Nitzold
The Communication Group invites you to our monthly research seminar, given on Wednesday, May 28th. This time the talk will be given by Mr. Walter Nitzold, who is a research assistant at the Vodafone Chair Mobile Communication Systems at TU Dresden, Germany, and has spent the last two months as a guest researcher at EIT, working with Professor Michael Lentmaier.
Title: Designing Spatially Coupled Codes for Arbitrary Rational Rates
Date: May 28, 2014
You are all very welcome!
Regular LDPC codes, originally introduced by Gallager in 1963, are well known for their good linear distance properties. The decoding thresholds although, are not necessarily very close to capacity when the suboptimal low-complexity belief propagation (BP) decoder is used. Therefore, nowadays the majority of code designs used in practice are based on irregular codes. These codes are specifically optimized for the BP decoder to push the thresholds close to capacity but at the price of sub-linear distance growth. This results in very good performance in the waterfall region while having high error floors.
The remarkable feature of LDPC Convolutional Codes (or spatially coupled LDPC codes) instead is that they can achieve capacity even in the regular case with a suboptimal BP decoder. No longer do performance close to capacity and linear distance growth exclude each other.
To extend good performance to arbitrary design rates, irregular codes had to be carefully optimized for every desired rate. We investigate the rate-flexibility of regular LDPC convolutional codes in conjunction with their performance and complexity. The analysis yields a simple construction approach for low-complexity LDPC convolutional codes that perform close to capacity for arbitrary rates.
The talk will also give an outlook on the extension to rate-compatible code constructions with LDPC convolutional codes.
2014-05-26 Ex-jobbspresentation: Alessandro Maretti
On Monday May 26 at 11.15 in E:3139, Alessandro Maretti will present his master thesis entitledbr
"Analysis of Internet traffic, applications and demand patterns".
The project has been performed in collaboration with Acreo Swedish ICT in our Celtic-Plus project NOTTS.
You are welcome to attend!
Analyzing the Internet traffic is an important issue because it allows discovering the today’s patterns, understanding the current trends and forecasting the future ones. This translates in benefits for a multitude of subjects, for example,Internet Service Providers and network operators can plan future network upgrades, downgrades, maintenance, and business strategies in order to keep their business profitable and competitive. Also, end users can take advantage of this competitiveness by choosing the operator that offers them the best quality of experience.
The main objectives of this analysis are to analyze Internet user behavior and Internet applications with particular focus on the behavioral difference between subscribers with different access speeds and on three particular categories of traffic: file sharing, gaming and personal cloud storage. In this thesis the issue is operationalized by analyzing the IP traffic in anactual Swedish municipal network with around 2800 active households. The empirical data are collected using Packet Logic, one of the most advanced solutions for deep packet inspection and then studied with a number of different methods and tools.
The results show that the subscribers are willing to upgrade their access speed in order to satisfy new needs. File sharing related traffic is decreasing in favor of legal audio-video streaming services but keeps being the most traffic consuming category. Subscribers with higher access speed exchange on average more traffic and use more bandwidth consuming applications. Mobile applications start penetrating among users; two of the six most played games are mobile-oriented. The user interaction patterns with such games are different from normal PC or console ones. Dropbox users have a tendency to upload small files to the cloud and use widely the collaboration tools that the software provides.
PhD thesis defence Chenxin Zhang
Date: 2014-05-27, at 10:15
Place: Lecture hall E:1406, Department of Electrical and Information Technology, Ole Römers väg 3, Lund University Faculty of Engineering
Opponent: Professor Bjorn De Sutter. Ghent University, Belgium
Abstract: Motivated by challenges from today's fast-evolving wireless communication standards and soaring silicon design cost, it is important to design a flexible hardware platform that can be dynamically reconfigured to adapt to current operating scenarios, provide seamless handover between different communication networks, and extend the longevity of advanced systems. Moreover, increasingly sophisticated baseband processing algorithms pose stringent requirements of real-time processing for hardware implementations, especially for power-budget limited mobile terminals. With existing hardware platforms such as Application-Specific Integrated Circuits (ASICs), Field-Programmable Gate Arrays (FPGAs), and Digital Signal Processors (DSPs), the contradictory design requirements of flexibility, computational performance, and hardware efficiency cannot be attained at the same time.
To achieve a balance between the aforementioned design requirements, a coarse-grained dynamically reconfigurable cell array architecture is proposed. The architecture is constructed from an array of heterogeneous function units interconnected through a hierarchical on-chip network. The adopted in-cell configuration scheme enables fast context switching between standards and between computational tasks during run-time. Although cell array is a generic hardware platform, this thesis focuses on the architectural development of the cell array tailored specifically for digital baseband processing of contemporary wireless communication systems. Various degrees of flexibilities among operating scenarios, algorithms, tasks, and supporting standards are exploited. Besides, high hardware efficiency is attained by conducting algorithm-architecture, hardware-software, and processing-memory co-design.
In this thesis, flexibility, performance and efficiency of the proposed architecture are demonstrated through two case studies. First, the cell array is deployed in a digital front-end receiver, aiming to support concurrent processing of multiple radio standards, 3GPP Long Term Evolution (LTE), IEEE 802.11n, and Digital Video Broadcasting for Handheld (DVB-H). Dynamic configuration of the cell array enables run-time switching between different operation modes, multi-standard single-stream and multi-standard multi-stream, in order to maximize hardware usage for attaining high computational performance while sufficing current processing demands. Implementation results show that the immense flexibility offered by the cell array comes at the cost of only about 16% area overhead in comparison to its ASIC counterpart. In the second study, the cell array architecture is extended with extensive vector computing capabilities, aiming to perform high-throughput MIMO signal processing. As an illustration, three computationally intensive blocks, namely channel estimation, pre-processing, and symbol detection, of a 4x4 MIMO processing chain in a 20 MHz 64-QAM 3GPP LTE-Advanced downlink are mapped and processed in real-time. With 6 processing and 10 memory cells deployed in the array, the achieved system throughput is 368 Mb/s at 500 MHz and the corresponding energy consumption for processing one information bit is 1.49 nJ/b. Compared to state-of-the-art implementations, the proposed solution outperforms related programmable platforms by up to 6 orders of magnitude in energy efficiency, and is 1.7-13.6 and 1.4-15 times less efficient than ASICs in terms of area and energy, respectively, when performing each individual task.
2014-05-16 Seminarie: Andreas Molisch
On Friday May 16 at 11.15-12 in E:2311 our colleague Andreas Molisch, now at USC, will give a seminar entitled
“Ranging, localization, and radar using ultrawideband signals”
You are all welcome to attend
Ultrawideband signals can inherently provide very high accuracy for the ranging between nodes, or the determination of range to passive objects. In this talk we will present a number of our recent results in this field. We first discuss a new algorithm that allows the determination of MULTIPLE target locations purely based on the measurements of time-of-arrival (i.e., without directional information). This algorithm solves, with a reasonable complexity, the problem of associating the multiple measured round trip times at various transmit-receive pairs with specific targets. We next review the problem of active ranging in the presence of interference, and present an algorithm that suppresses interference better than the "standard" exploitation of spreading gain when time-hopping impulse radio is used; experimental results confirm the superior performance. We finally briefly review experiments of localizing breathing persons "around the corner" (i.e., without line of sight) using a UWB MIMO radar.
2014-05-16 Ex-jobbspresentation: Diptyajit Choudhury
Diptyajit Choudhury will present his master these, entitled "Network Interface Cards and Switch Integration” on Friday May 16th at 13:15 in E:2311.
Today server computers are being stacked in racks. A computer rack consists of 40+ server computers connected to a top of rack switch. This top of rack switch is then connected to other racks. Together they form a large cluster of computers which are used in today's cloud computing. Each server has one or sometimes two Network Interface Cards (NICs) which are connected to the top of rack switch. The functionality of the NIC is to transport the packets from the server's main memory onto a standard such as Ethernet and then transfer them to the network. However today inside a server the protocol to transport packets in and from the main memory is already done by Peripheral Component Interconnect Express (PCIe) protocol. It can therefore be argued that the NIC's function is useless. Since it will only translate PCIe packets to Ethernet packets. Hence the NIC functionality, i.e. going from PCI express to Ethernet can be put into the switch instead. In this project a NIC is built from scratch to understand how it works and understand networking and networking hardware to achieve this vision. Then the PCIe protocol is studied in detail and a customized PCIe IP is implemented and verified to prove that it can be utilized for the project. Hardware tests are conducted on a FPGA interfaced with a host computer using this protocol. Finally, a theoretical investigation of the costs and feasibility of supporting a new networking protocol called Quantized Congestion Notification (QCN) in a novel NIC-switch hybrid device is provided.
2014-05-15 AIMday® Wireless
LUIS (LU Innovation System) and EIT invite regional industry to the meeting platform AIMday® Wireless in Lund on Thursday 15th May at the Old Bishop’s House. Free, good food and highly interesting discussions in a relaxed environment.
Companies' need for new knowledge are matched with academic expertise from EIT and other institutions and AIMday brings new perspectives to actual problems. The event is centred on small group one-hour discussions and will hopefully render useful contacts, collaborations, and new paths in solving companies’ future needs. The format is based on submission of questions from industry, followed by signing up for interest around the questions from the researchers.
Based on this we will perform matching and establish the group discussions. We are currently approaching industry from a long list:
Ericsson, Sony, Sigma Connectivity, Axis, Anoto, Doro, Blackberry, ARM, Anritsu, Combain, Eon, IBM, Huawei and many more.
The interest is great but we will know the final attendee list first after the matching is done. Don’t miss the opportunity to take part in this highly interesting day! For more information, check out the website www.aimday.se, the flyer or get get in touch with email@example.com or firstname.lastname@example.org. Or stop by at Anders room for a chat.
2014-05-09 Seminar with Anders Derneryd
Welcome to a seminar with Anders Derneryd, May 9, 2014. The seminar will be held at Department of Electrical and Information Technology, Lund University.
Place: E-huset, E:2311
Date: May 9, 2014
Time: 14.15 - 16.30
5 min Welcome and introduction
15 min Gerhard Kristensson: ”How it all started and continued”
30 min Anders Derneryd (flashbacks on AD’s career and development in Sweden)
30 min Coffee break
15 min Vincent: “A tale of two dipoles and more”
20 min Thomas, Ying & Vanja, Sony: “ A historic review on terminal-antenna-development during 30 years"
15 min Fredrik Tufvesson
2014-05-07 Workshop Cloud Control
LCCC, Lund Center for Control of Complex Engineering Systems, will host a workshop at the Old Bishops Palace in Lund, May 7-9.
The talks at the workshop will address control and management of complex cloud infrastructures and the event will also provide opportunities for academy and industry to establish interdisciplinary collaborations.
Example of cloud-related topics covered at the event:
Application management, power costs, deadline scheduling, control systems, elasticity management, autonomics, SLAs, energy management and more.
Representation from (among others) universities in Lund, Stockholm, Umeå, Vienna, Aalto, Grenoble, Shanghai, Washington, Haifa.
Representation from (among others) industry: Microsoft, Google, HP, Bell-Labs/Alcatel-Lucent.
Read more at:
2014-04-29 Ex-jobbspresentation: Ateeq Ur Rahman Shaik
On Tuesday, April 29 at 16.15, in E:2349, Ateeq Ur Rahman Shaik will present his Master’s thesis work:
“Hardware Implementation of the Exponential Function Using Taylor Series and Linear Interpolation”
This thesis work is targeted towards ASIC implementation of the exponential function. Generally unary functions like trigonometric, logarithmic and exponential are useful in computer graphics, signal and image processing for high speed applications. Sometimes software implementation does not meet the requirements in some applications, where speed is of utmost importance, i.e. it has to be implemented in hardware. In this work, the exponential function is implemented using two different architectures that are using Taylor series and Linear Interpolation. Both architectures are mainly focused on low power, minimum area and better performance. A comparison is done between the two architectures. The designs are synthesized in synopsis Design Vision STM065nm process technology with target libraries with high threshold voltage and low threshold voltage. Synopsis PrimeTime is used for the estimation of dynamic power consumption.
2014-04-23 Seminar: Buon Kiong Lau
This month’s Communication Group seminar will be given on Wednesday the 23rd, and the two-part talk is presented by Buon Kiong (Vincent) Lau.
Title: 1) MIMO Antenna Design for Compact Terminals – Lessons Learned;
2) Publish or Perish – Surviving Academic Research
Speaker: Buon Kiong (Vincent) Lau
Date: Apr 23, 2014
You are all very welcome!
I will begin my talk by presenting a perspective on MIMO antenna design for compact terminals, based on our activities in the area over the past ten years. A lot has been going on in this field over this period - we have been fortunate enough to have the opportunity to work on some very interesting topics, one after another.
For the second part of my talk, I would like to share some experience I have gained from being an associate editor for the IEEE Transactions on Antennas and Propagation (journal with the third highest number of downloads in IEEEXplore) since 2010. I am aware that quite a number of the seniors at EIT are associate editors for other IEEE journals, with different editorial cultures, so I am only presenting my side of the story.
2014-04-11 Ex-jobbspresentation: Aohan Jin och Siyuan Fu
Aohan Jin and Siyuan Fu will present their Master thesis work on April 11th (Friday) at 13:15 in E:3139
The thesis title is: "Real-time Implementation of Digital Cavities"
Supervisors are Khadga Karki (Chemical Physics), Liang Liu (EIT), and Fredrik Edman (LU Innovation System). The examiner is Viktor Öwall
This master thesis demonstrates a new methodology for high precision measurement of ultra-high frequency signals. The method is based on the theory of digital cavity that recently has been introduced. This digital cavity algorithm has greatly increased the precision of ultra-high frequency signal measurements. The Q-factor of a digital cavity can reach up to 10^9, which is significantly higher than that of alternatives on market (around 10^6). In order to conduct real-time analysis of gigahertz signals, an FPGA-based digital cavity accelerator has been designed and implemented using the Xilinx XUPV5- LX110T platform. With the processing capability of the FPGA, the digital cavity can analyze signals of several gigahertz frequency at a Q-factor of up to 10^8 in real time.
2014-04-10 Seminar: Prof Alan Seabaugh
With short notice the schedule for a visit by Prof Alan Seabaugh from University of Notre Dame, US, has been arranged. We are very happy that he will be able to give a seminar tomorrow at 11.15 in E:1406.
He is directing US efforts targeting performance beyond CMOS in a huge program funded by Intel, IBM, Globalfoudries, Texas Instruments, US government and DARPA (see abstract). We shall be very happy that key persons put Lund on their agenda!
Title: "Status and progress in the development of steep subthreshold swing transistors"
The seminar will be in on Thursday April 10 at 11.15 in E: 1426
Tunnel field-effect transistors (TFETs) are under investigation to enable power supply reduction under 0.5 V. In 2013, the Semiconductor Research Corporation (SRC) along with the U. S. Defense Advanced Research Project Agency launched the Semiconductor Technology Advanced Research Network (STARnet), a five-year, $194M university research effort consisting of six centers and 39 universities to explore future directions for the microelectronics industry. The aim of the Center for Low Energy Systems Technology (LEAST), based at Notre Dame, is to provide the fundamental analysis, experimental data, and benchmarking needed advance electronics beyond the performance limits of CMOS. This talk will review the current status of steep-subthreshold-swing transistors and research directions of LEAST (www.least.nd.edu) and discuss an analytic SPICE model for TFETs being used to explore circuits.
2014-04-03 Seminar: Professor Zhengya Zhang
On April 3 at 3.15pm in E:2311 Associate Professor Zhengya Zhang from University of Michigan, Ann Arbor, will give a seminar titled:
Energy-Efficient DSPs by Algorithm and Circuits Co-Design
Conventional energy-efficient circuit designs are conservative to guarantee reliable general-purpose computing. Signal processing algorithms are often more forgiving, allowing significant energy reduction by imperfect but energy-efficient circuits and approximate computing. In this talk, I will present our recent chip designs for communication, computer vision, and remote sensing to demonstrate high energy efficiency by algorithm and circuits co-design. The co-design strategy offers a promising route towards continued improvement in performance and efficiency using deeply scaled devices.
Biography: Zhengya Zhang received the B.A.Sc. degree from the University of Waterloo, Canada, in 2003, and the M.S. and Ph.D. degrees from the University of California, Berkeley, in 2005 and 2009, respectively. Since 2009, he has been on the faculty of the University of Michigan, Ann Arbor. Dr. Zhang received the National Science Foundation CAREER Award in 2011 and the Intel Early Career Faculty Award in 2013. He received the David J. Sakrison Memorial Prize for outstanding doctoral research at UC Berkeley and the Best Student Paper Award at the Symposium on VLSI Circuits. He is an associate editor for the IEEE Transactions on Circuits and Systems—I: Regular Papers, and the IEEE Transactions on Circuits and Systems—II: Express Briefs.
Zhengya will be the Faculty opponent during the disputation of Isael Diaz on April 4.
2014-04-04 PhD thesis defence Isael Diaz
Date: 2014-04-04, at 10:15
Place: lecture hall E:1406, E-building, Ole Römers väg 3, Lund University Faculty of Engineering
Opponent: Assistant Prof. Zhengya Zhang. University of Michigan, USA.
Algorithm-Architecture Co-Design for Digital Front-Ends in Mobile Receivers
ISSN 1654-790X No. 56, 2014.
Abstract: The methodology behind this work has been to use the concept of algorithm-hardware co-design to achieve efficient solutions related to the digital front-end in mobile receivers. It has been shown that, by looking at algorithms and hardware architectures together, more efficient solutions can be found; i.e., efficient with respect to some design measure. In this thesis the main focus have been placed on two such parameters; first reduced complexity algorithms to lower energy consumptions at limited performance degradation, secondly to handle the increasing number of wireless standards that preferably should run on the same hardware platform. To be able to perform this task it is crucial to understand both sides of the table, i.e., both algorithms and concepts for wireless communication as well as the implications arising on the hardware architecture.
It is easier to handle the high complexity by separating those disciplines in a way of layered abstraction. However, this representation is imperfect, since many interconnected "details" belonging to different layers are lost in the attempt of handling the complexity. This results in poor implementations and the design of mobile terminals is no exception. Wireless communication standards are often designed based on mathematical algorithms with theoretical boundaries, with few considerations to actual implementation constraints such as, energy consumption, silicon area, etc. This thesis does not try to remove the layer abstraction model, given its undeniable advantages, but rather uses those cross-layer "details" that went missing during the abstraction. This is done in three manners:
In the first part, the cross-layer optimization is carried out from the algorithm perspective. Important circuit design parameters, such as quantization are taken into consideration when designing the algorithm for OFDM symbol timing, CFO, and SNR estimation with a single bit, namely, the Sign-Bit. Proof-of-concept circuits were fabricated and showed high potential for low-end receivers. In the second part, the cross-layer optimization is accomplished from the opposite side, i.e., the hardware-architectural side. A SDR architecture is known for its flexibility and scalability over many applications. In this work a filtering application is mapped into software instructions in the SDR architecture in order to make filtering-specific modules redundant, and thus, save silicon area. In the third and last part, the optimization is done from an intermediate point within the algorithm-architecture spectrum. Here, a heterogeneous architecture with a combination of highly efficient and highly flexible modules is used to accomplish initial synchronization in at least two concurrent OFDM standards. A demonstrator was build capable of performing synchronization in any two standards, including LTE, WiFi, and DVB-H.
2014-03-28 Ex-jobbspresentation: Carin Cedergren
Fredag den 28/3 kl 9.15-10.00 i E2349 presenterar Carin Cedergren sitt exjobb: "Validaton Testing of Analog Certification Testing Equipment".
(The presentation will be in Swedish)
Välkomna, Bertil Larsson
The certification laboratory at Nokia Copenhagen ensures that the mobile phones developed by Nokia meets the requirements according to specific technology standards. The laboratory is focused on test concerning the communication between SIM/USIM-card and the mobile phone. This communication is monitored and measured by a probe supplied by an external manufacturer. Once every year the probe is sent to the manufacturer for calibration. Interest has been shown to make testing of the measuring device easier and more reliable. These validation tests occur in between the calibrations and are done to ensure the accuracy of the testing. The part of the certification testing procedure that will be the focus of this master thesis are the analogue tests according to the test case specifications found in the ETSI documentation. These tests concern, among other things, the voltage levels on the different contacts on the SIM/USIM-card, the rise- and fall time and cycle ratio of those signals. The goal of this master thesis is to determine how these tests should be carried out in order to ensure the reliability of the probe while still keeping the test fast and easy to perform.
2014-03-24 Seminar: Prof. Sean Hum
A visiting colleague Assoc. Prof. Sean Hum from the University of Toronto will present a seminar next Mon (24 Mar 2014) at 2.15pm in room E:3139 (approx. 40 min + questions). Details are given below.
"Reconfigurable Antennas: Architectures, Technologies, and Their Exciting Future"
Buong Kiong Lau
Modern radio systems have expanded our ability to communicate, sense our world, and deliver information ubiquitously in new and exciting ways. Future systems will depend on adaptive radio technologies to provide agility in dynamic channel environments, increased system capacity, improved robustness to interference, and cost-effective communications and sensing solutions. These needs have created exciting opportunities for innovation at the physical layer of these systems, particularly in the area of reconfigurable antennas. These antennas possess the ability to electronically reconfigure their radiating and electrical characteristics, including their radiation pattern, polarization, and frequency of operation. These high-speed “field-programmable” antennas are adding new dimensions to wireless system capabilities in applications ranging from spectrum-sensing for cognitive radio to low-cost beamforming for next-generation communication and remote-sensing antennas.
This talk will review a wide range of reconfigurable antenna architectures and technologies developed in recent years. First, reconfigurable aperture antennas will be presented as a technology for realizing high-gain beamforming systems achieving the performance of phased arrays using a fraction of the cost of these systems. This will be followed by a review of more general pattern- and frequency-reconfigurable antennas, which have enabled a number of advances to be made in realizing compact diversity antennas in mobile applications, particularly for Long Term Evolution (LTE) networks. Finally, some emerging concepts in the application of artificial electromagnetic materials to the design of next-generation reconfigurable antennas will be presented.
Sean Victor Hum was born in Calgary, Alberta, Canada. He received his B.Sc., M.Sc. and Ph.D. degrees from the University of Calgary in 1999, 2001, and 2006 respectively. From 1997-2006 he also worked with TRLabs on a variety of projects in wireless and radio-over-fibre applications. In 2006 he joined the Edward S. Rogers Sr. Department of Electrical and Computer Engineering at the University of Toronto where he currently serves as an associate professor. Prof. Hum leads the reconfigurable antenna laboratory at the UofT, and along with his students, he is conducting research in the areas of reconfigurable antennas and RF systems, antenna arrays, and antennas for space applications. He is currently on research leave at the European Space Agency’s Space Research and Technology Centre (ESA-ESTEC), in Noordwijk, The Netherlands.
Prof. Hum received the Governor General's Gold Medal for his MSc. work on radio-on-fibre systems in 2001 and an IEEE Antennas and Propagation Society Student Paper award for his work on tunable reflectarrays in 2004. In 2006, he received an ASTech Leaders of Tomorrow award for his work on reconfigurable antennas. In 2012 he was awarded an Early Researcher Award by the government of Ontario. On the teaching side, Prof. Hum has received four UofT Departmental Teaching Awards since 2007, and most recently, an Early Career Teaching Award in 2011. Prof. Hum is a Senior Member of the IEEE, a member of URSI (the International Union of Radio Science), and an Associate Editor of the IEEE Transactions on Antennas and Propagation.
2014-03-21 PhD thesis defence Mattias Andersson
Date: 2014-03-21, at 10:15
Place: E:1406, Department of electrical and information technology, Ole Römers väg 3, 223 63 Lund
Opponent: Professor Maurits Ortmanns. University of Ulm, Germany
Continuous-Time Delta-Sigma Modulators for Wireless Communication
Series of licentiate and doctoral dissertations, ISSN 1654-790X, no.55, Department for Electrical and Information Technology, 2014.
Abstract: The ever increasing data rates in wireless communication require analog to digital converters (ADCs) with greater requirements on speed and accuracy, while being power efficient to prolong battery life. This dissertation contains an introduction to the field and five papers that focus on the continuous-time (CT) Delta-Sigma modulator (DSM) as ADC.
Paper I analyses the performance degradation of dynamic nonlinearity in the feedback DAC of the DSM, caused by Vth mismatch in the current-switching (differential) pair of a current-steering DAC. A model is developed to study return-to-zero (RZ) and non-return-to-zero (NRZ) feedback DACs, with and without data-weighted averaging (DWA), where an RZ DAC with DWA recovers the performance.
Paper II and III presents a feedback scheme for improved robustness against variations in loop delay. An RZ pulse, centered in the clock period, is used in the innermost feedback path which has the highest sensitivity to loop delay, while NRZ pulses are adopted in the outer feedback paths to reduce the sensitivity to clock jitter and lower the integrator slew rate requirements. Furthermore, the otherwise obligatory loop delay compensation path (e.g. an additional DAC and adder) could be omitted to reduce hardware complexity. A discrete-time model of the feedback scheme confirms a negligible loss in performance. The 3rd-order CT DSM in 65nm CMOS with 9MHz LTE bandwidth achieves 69/71dB SNDR/SNR and consumes 7.5mW from a 1.2V supply. Measurements with OFDM signals verify an improved tolerance to blockers outside the signal band of the DSM.
Paper IV and V present two filtering ADCs, where the DSM is merged into the channel select filter to suppress the noise from the DSM. The first and second prototypes provide a 2nd- and 3rd-order channel select filtering and improve the SNDR of the DSM by 14dB and 20dB, respectively, which in theory can be exploited to reduce the DSM power consumption by four to eight times.
The first prototype has a 288MHz clock frequency, a 9MHz LTE bandwidth, a 2nd-order Butterworth filter response with 12dB gain, an input-referred noise of 8.1nV/sqrt(Hz), an in/out-of-band IIP3 of 11.5/27dBVrms, and a power consumption of 11.3mW. The second prototype is clocked at 576/288MHz with an 18.5/9MHz LTE bandwidth, a Chebyshev filter response with 26dB gain, a low input-referred noise of 5nV/sqrt(Hz), and an in/out-of-band IIP3 of -8.5/20dBVrms, with a power consumption of 7.9/5.4mW for 2xLTE20/LTE20 mode. The prototype was characterized for OFDM modulated blockers and essentially meets the cellular standard LTE Rel. 11. A delay, introduced by the feedback DAC, is compensated by adjusting the filter coefficients to restore the original Chebyshev filter function.
Both prototypes have state-of-the-art power efficiency compared to other filtering ADCs and are comparable or better than a stand-alone filter. Furthermore, the filtering ADC provides both filtering and A/D conversion, which suggests that the A/D conversion is included in a power efficient manner, broadly speaking "for free".
2014-03-19 Seminar: Ghassan Dahman
The Communication Group’s “Wednesday seminar” series continues, this time with Ghassan Dahman presenting.
Title: "An overview of the multi-link propagation measurements and channel modelling activities at EIT"
Speaker: Ghassan Dahman
Date: March 19, 2014
In this talk, I will give a brief description of the channel measurements and channel modelling activities that take place at EIT as part of the “Distributed antenna systems for efficient wireless systems” (DISTANT) project. The talk will include discussing some of the results from last year’s measurement campaigns as well as providing a brief description about the multi-link propagation measurement campaigns that are planned for 2014.
2014-03-12 Ex-jobbspresentation : Liang Jiasheng
Liang Jiasheng will present his MSc theisis (details below) on Wednesday March 12, at 13.15, in E:2311. The final project was undertaken at Nokia Siemens Networks in Munich, Germany.
A Coordinated Optimization Algorithm of Inter-RAT Handover Thresholds and Time-to-Trigger in Self-Organizing Networks
The limited coverage of Long Term Evolution (LTE) system results in many inter-radio access technology (RAT) handovers from LTE to legacy second generation (2G) or third generation (3G) mobile system and vice versa. Trouble-free operation of inter-RAT handovers requires the optimization of the handover parameters of different RATs. Currently, the handover parameters are optimized manually and it requires human intervention and increases operational expenditures (OPEX). To reduce costs and achieve an improved network performance, a self-optimizing algorithm for the inter-RAT handover parameters is foreseen in upcoming Self-Organizing Networks (SON) standards. The parameters affecting the inter-RAT handovers are mainly signal strength (or quality) thresholds and a timer called Time-to-Trigger (TTT). This thesis continues by further exploring the optimization of TTT using a coordinated approach with handover thresholds on the basis of the existing inter-RAT mobility robustness optimization (MRO) algorithm. Evaluations are performed by different parameter coordination paradigms which present the best inter-RAT handover performance on various User Equipment (UE) speeds.
2014-03-14 Disputation: Karl-Magnus Persson
Karl-Magnus Persson disputerar den 14/3 kl 10:15 i sal E:1406,
Ole Römers väg 3 (E:huset).
Titel: "Nanowire Transistors and RF Circuits for Low-Power Applications"
PhD thesis defence Rohit Chandra
Date: 2014-03-04, at 10:15
Place: Lecture hall E:1406, E-building, Ole Römers väg 3, Lund University Faculty of Engineering
Opponent: Gert Frölund Pedersen. Aalborg University, Denmark
Antennas, Wave Propagation, and Localization in Wireless Body Area Networks
ISSN ISSN 1654-790X, 2014.
Abstract: A network of communicating wireless devices that are implantable, wearable or within close proximity of a human body is called wireless body area network (WBAN). The propagation channels for the devices in the WBAN are either through the body or over the body. This results in the attenuation and the absorption of electromagnetic waves radiated by the antenna of these devices due to the lossy tissues of the body. With a proper antenna and knowledge of the signal loss between the devices in the WBAN, a reliable wireless link can be designed. This thesis presents the investigations done for the antennas, wave propagation, and localization for various applications of these networks. The investigated applications are: (1) Binaural Hearing Aids (Paper I \& Paper II), (2) Sensor placed Around the Body (Paper III \& Paper IV), (3) Localization of Wireless Capsule Endoscope (Paper V), and (4) In-Mouth Devices.
Binaural hearing aids communicate with each other for synchronization such as adjustment of volume or programing for the listening environment. In Paper I, antennas suitable in size and technical performance at 2.45 GHz for in-the-ear (ITE) and in-the-canal (ITC) placement of the hearing aids are presented. The ear-to-ear link loss found from the finite-difference-time-domain (FDTD) simulations for the ITE case was 48 dB and that for the ITC case was $92$~dB for the SAM head. The ITE case was further investigated on realistic heterogeneous phantoms of different age and head sizes. The link loss in the ITE case for an adult heterogeneous phantom was found to be $79$~dB. It was found that the absence of the pinna (outer ear) and the lossless shell under-estimates the link loss for the SAM phantom. Hence, a phantom with the lossy outer shell and the pinnas should be used for a proper estimation of the ear-to-ear link loss. In Paper II, an analytical model is presented for the ear-to-ear link loss based on the attenuation of the creeping wave over an elliptically modeled cross-section of the head. The model takes into account the dominant paths having most of the power of the creeping wave from the antenna in one ear to the antenna in the other ear and the effect of the pinnas. Simulations were done to validate the model using the ITE placement of the antenna at 2.45 GHz on heterogeneous phantoms of different age-groups and head sizes, showing a good agreement with the model. The effect of the pinnas was verified through measurements on a phantom where the pinnas fabricated by 3D-printing were included.
In Paper III, an analytical model is developed for wireless propagation around the body based on the attenuation of creeping waves over an elliptical cross-section of the torso. The model includes the effect of the arms. It was verified through FDTD simulations on a numerical phantom with various arm positions. It was shown that it is critical to include the effect of the arms as their presence might result in extreme fading dips at some sensor positions. Further, a temporal variation in the power received by sensors placed around the torso was found when the arms moved while walking. This result is used in Paper IV to develop an approach to analyze the movements of the arms while walking using three wearable wireless devices. One of the devices is a transmitter placed at the back and the other two are symmetrically placed receivers at the side that record the power variation due to the arm movements. For such a placement of sensors, the variation in the receiver will be more or less symmetrical if the arm swing normally. However, a large degree of asymmetry in the arms swing will result in an asymmetrical variation in the received power by the two receivers. This was confirmed by simulations and measurements.
Wireless capsule endoscopy (WCE) overcomes the problems of conventional endoscopy like not reaching the entire small-intestine. However, due to the lossy tissues, the localization of the capsule is a challenging task which is required in order to know the position of an abnormality captured in the endoscopy image. Paper V presents a method for the localization of an in-body RF source, as in WCE, based on microwave imaging. The electrical properties of the tissues and their distribution were found from microwave imaging at $403.5$~MHz. The method was applied on synthetic data obtained after addition of the white Gaussian noise to the simulated data of a simple circular phantom, and a realistic phantom for the 2D transverse magnetic polarization. The root-mean-square of the error distance between the various actual and estimated positions was found to be within $9$~mm for both the phantoms showing the capability of the algorithm to localize the capsule in the presence of noise with a good accuracy.
An in-mouth device is a tongue controlled device used by the paraplegic or quadriplegic patients to control a wheelchair or type on a computer. Although the device is not surgically implanted but the performance of its antenna is influenced by the lossy tissues of the mouth or head in a similar way as that of an implant. In this work, antennas suitable in size and performance for such devices were investigated.
PhD thesis defence Taimoor Abbas
Date: 2014-02-24, at 13:15
Place: E:1406, Ole Römers väg 3, 22363 Lund.
Opponent: Prof. Alex Grant. University of South Australia
Measurement Based Channel Characterization and Modeling for Vehicle-to-Vehicle Communications
Series of licentiate and doctoral dissertations, ISSN 1654-790X (No. 58), Department of Electrical and Information Technology, Lund University, Sweden, 2014.
Abstract: Vehicle-to-Vehicle (V2V) communication is a challenging but fast growing technology that has potential to enhance traffic safety and efficiency. It can also provide environmental benefits in terms of reduced fuel consumption. The effectiveness and reliability of these applications highly depends on the quality of the V2V communication link, which rely upon the properties of the propagation channel. Therefore, understanding the properties of the propagation channel becomes extremely important. This thesis aims to fill some gaps of knowledge in V2V channel research by addressing four different topics. The first topic is channel characterization of some important safety critical scenarios (papers I and II). Second, is the accuracy or validation study of existing channel models for these safety critical scenarios (papers III and IV). Third, is about channel modeling (paper V) and, the fourth topic is the impact of antenna placement on vehicles and the possible diversity gains. This thesis consists of an introduction and six papers:
Paper I presents a double directional analysis of vehicular channels based on channel measurement data. Using SAGE, a high-resolution algorithm for parameter estimation, we estimate channel parameters to identify underlying propagation mechanisms. It is found that, single-bounce reflections from static objects are dominating propagation mechanisms in the absence of line-of-sight (LOS). Directional spread is observed to be high, which encourages the use of diversity-based methods.
Paper II presents results for V2V channel characterization based on channel measurements conducted for merging lanes on highway, and four-way street intersection scenarios. It is found that the merging lane scenario has the worst propagation condition due to lack of scatterers. Signal reception is possible only with the present LOS component given that the antenna has a good gain in the direction of LOS. Thus designing an antenna that has an omni-directional gain, or using multiple antennas that radiate towards different directions become more important for such safety critical scenarios.
Paper III presents the results of an accuracy study of a deterministic ray tracing channel model for vehicle-to-vehicle (V2V) communication, that is compared against channel measurement data. It is found that the results from measurement and simulation show a good agreement especially in LOS situations where as in NLOS situations the simulations are accurate as far as existing physical phenomena of wave propagation are captured by the implemented algorithm.
Paper IV presents the results of a validation study of a stochastic NLOS pathloss and fading model named VirtualSource11p for V2V communication in urban street intersections. The reference model is validated with the help of independent channel measurement data. It is found that the model is flexible and fits well to most of the measurements with a few exceptions, and we propose minor modifications to the model for increased accuracy.
Paper V presents a shadow fading model targeting system simulations based on channel measurements. The model parameters are extracted from measurement data, which is separated into three categories; line-of-sight (LOS), LOS obstructed by vehicles (OLOS), and LOS blocked by buildings (NLOS), with the help of video information recorded during the measurements. It is found that vehicles obstructing the LOS induce an additional attenuation in the received signal power. The results from system level vehicular ad hoc network (VANET) simulations are also presented, showing that the LOS obstruction affects the packet reception probability and this can not be ignored.
Paper VI investigates the impact of antenna placement based on channel measurements performed with four omni-directional antennas mounted on the roof, bumper, windscreen and left-side mirror of the transmitter and receiver cars. We use diversity combining methods to evaluate the performance differences for all possible single-input single-output (SIMO), multiple-input single-output (MISO) and multiple-input multiple-output (MIMO) link combinations. This investigation suggests that a pair of antennas with complementary properties, e.g., a roof mounted antenna together with a bumper antenna is a good solution for obtaining the best reception performance, in most of the propagation environments.
In summary, this thesis describes the channel behavior for safety-critical scenarios by statistical means and models it so that the system performance can be assessed in a realistic manner. In addition to that the influence of different antenna arrangements has also been studied to exploit the spatial diversity and to mitigate the shadowing effects. The presented work can thus enable more efficient design of future V2V communication systems.
2014-02-12 Seminar: Fredrik Rusek
The Communication Group would like to welcome you to our first “Wednesday seminar” of this year, given on February 12th. The talk will be given by Fredrik Rusek.
Title: "An overview of some selected patents from my time at Huawei"
Speaker: Fredrik Rusek
Date: February 12, 2014
During the time I spent at Huawei in 2013, I filed a number of LTE related patents. In this talk I will briefly review 3 of them:
(i) A hardware efficient 4x4 MIMO detector for 64QAM inputs that requires almost no multiplications at all,
(ii) A quasi maximum-likelihood frequency offset estimator suitable for LTE with wide capture range, and
(iii) Non-standard methods for CQI reporting with LTE’s transmission mode 3 (TM3).
I plan to also give a very short overview of the patent-process which could be of interest to Ph.D students.
2014-01-28 Ex-jobbspresentation: Lian Xiiangyu
Lian Xiiangyu will present his master thesis on Tuesday Jan 28th at 13:13 in E:2311. Supervisor Michal Stala
Title: Encoder and Decoder Design of LTE Physical Downlink Control Signals
As mobile communication technologies have evolved rapidly during last decades. Wireless communication standards such as LTE are developed with the need of new serves on mobile devices.
In this report, the design and implementation of encoder and decoder of LTE physical-layer downlink control signaling, which provides control information for downlink and uplink transmission, are presented.
The encoder is designed to encode downlink control information with multiple configurations while decoder is designed to decode the encoded data and returns user expected control information. The encoder is implemented in MATLAB and decoder is implemented in MATLAB and on Xilinx XUPV5-LX110T evaluation platform.
The Xilinx XUPV5-LX110T evaluation platform uses a serial port to communicate with a computer. The encoded data can be transmitted through HyperTerminal to the FPGA and decoded data can be display on HyperTerminal.
The decoder implemented on FPGA is an embedded system using a Xilinx Viterbi Decoder v7.0 IP as hardware accelerated core while other functions are implemented in software.