Electrical and Information Technology

Faculty of Engineering LTH | Lund University

Event archive

Lic. Seminar: Improving Throughput and Minimising Age of Information in dense WLANs, Using Cooperative Techniques by Antonio Fra

Published: 2017-12-13

Title: Improving Throughput and Minimising Age of Information in dense WLANs, Using Cooperative Techniques

Presenter: Antonio Franco - see

Reviewer: Professor Markus Fiedler, Blekinge Institute of Technology (BTH)

Supervisor: Professor Björn Landfeldt, EIT

Examiner: Universitetslektor Erik Larsson, EIT


Mobile and wireless data are in increasing demand worldwide. New trends such the Internet of Things paradigm and the Smart City paradigm describe scenarios comprising thousands of devices all exchanging informations between each others wirelessly ? or through the WAN to another device, possibly connected to another WLAN. Operators and radio engineers are faced with the problem of designing efficient ways to share the electromagnetic spectrum ? a scarce and expensive resource ? between thousands of devices.

In this context, operators look at the unlicensed spectrum as possible solu- tion to complement the existing infrastructure. Unfortunately, the IEEE 802.11 MAC family, the most widespread MAC protocol in the unlicensed portion of the spectrum, still suffers when managing a large number of interconnected devices. In this thesis we are both addressing the open problems in the IEEE 802.11 MAC scheme and our contributions on their solution. 
Specifically, in the first part of the thesis we are going to present the IEEE 802.11 MAC scheme and the challenges it faces, along with solutions already present in literature. We are also going to show a new metric recently defined in literature called the Age of Information (AoI). This new metric is a measure how fresh is the piece of information stored in a remote receiver. It received interest in the literature, but little is known how it behaves in a IEEE 802.11 WLAN.
In the second part of the thesis we present two papers that try to address the problem of designing new protocols that let the devices cooperate in order to achieve a common goal. They specifically focus on two metrics. The first paper addresses throughput and collisions reduction through a new MAC scheme that uses RSSI to identify other devices in a WLAN, and uses a priority base access system in order to cooperate in turns with them. We show, through simulation, that this scheme outperforms the classical IEEE 802.11 DCF mode of operation, especially in WLANs subject to high loads.

The second paper addresses the AoI both in terms of average and variance, for sensor nodes immersed in a dense WLAN that send pieces of information to a remote server via a WAN connection. We study both those metrics for a link with high variance and low variance delay. We construct and test, via means of simulations, an AoI-aware MAC, called LUPMAC - Latest Update Medium Access Scheme, aimed at reducing both the average AoI and the AoI variance at the remote server side, being also resilient to variations on the wired remote connection.

In those two papers we present two schemes suitable for the unlicensed spectrum environment, addressing both scheduling and queuing policies. They are only slight modifications to the already widely deployed IEEE 802.11 MAC. They significantly improve the metrics they focus on. They tend not to rely on a centralized unit, as most random access schemes do, and let the devices cooperate to a certain extent in order not to pollute the channel with undesired retransmissions. 

When: 2018-08-22 13:00 to 2018-08-22 13:00
Location: E:3139


ELLIIT Distinguished Lecture on Robot Skill Learning by Prof. Jan Peters

Published: 2018-06-04

Speaker: Prof. Jan Peters, Technische Universitaet Darmstadt and Max-Planck Institute for Intelligent Systems

Abstract: Autonomous robots that can assist humans in situations of daily life have been a long standing vision of robotics, artificial intelligence, and cognitive sciences. A first step towards this goal is to create robots that can learn tasks triggered by environmental context or higher level instruction. However, learning techniques have yet to live up to this promise as only few methods manage to scale to high-dimensional manipulator or humanoid robots. In this talk, we investigate a general framework suitable for learning motor skills in robotics which is based on the principles behind many analytical robotics approaches. It involves generating a representation of motor skills by parameterized motor primitive policies acting as building blocks of movement generation, and a learned task execution module that transforms these movements into motor commands. We discuss learning on three different levels of abstraction, i.e., learning for accurate control is needed to execute, learning of motor primitives is needed to acquire simple movements, and learning of the task-dependent ?hyperparameters? of these motor primitives allows learning complex tasks. We discuss task-appropriate learning approaches for imitation learning, model learning and reinforcement learning for robots with many degrees of freedom. Empirical evaluations on a several robot systems illustrate the effectiveness and applicability to learning control on an anthropomorphic robot arm. These robot motor skills range from toy examples (e.g., paddling a ball, ball-in-a-cup) to playing robot table tennis against a human being and manipulation of various objects. 

Bio: Jan Peters is a full professor (W3) for Intelligent Autonomous Systems at the Computer Science Department of the Technische Universitaet Darmstadt and at the same time a senior research scientist and group leader at the Max-Planck Institute for Intelligent Systems, where he heads the interdepartmental Robot Learning Group. Jan Peters has received the Dick Volz Best 2007 US PhD Thesis Runner-Up Award, the Robotics: Science & Systems - Early Career Spotlight, the INNS Young Investigator Award, and the IEEE Robotics & Automation Society's Early Career Award. Recently, he received an ERC Starting Grant. Jan Peters has studied Computer Science, Electrical, Mechanical and Control Engineering at TU Munich and FernUni Hagen in Germany, at the National University of Singapore (NUS) and the University of Southern California (USC). He has received four Master's degrees in these disciplines as well as a Computer Science PhD from USC. Jan Peters has performed research in Germany at DLR, TU Munich and the Max Planck Institute for Biological Cybernetics (in addition to the institutions above), in Japan at the Advanced Telecommunication Research Center (ATR), at USC and at both NUS and Siemens Advanced Engineering in Singapore. 

When: 2018-06-12 15:30 to 2018-06-12 16:30


PhD Dissertation: Spatially coupled turbo-like codes

Published: 2018-05-31

Author: Saeedeh Moloudi

Opponent: Krishna Narayanan (Professor)

When: 11 June at 9.15

Loaction: Lecture hall E:1406, building E, Ole Römers väg 3, Lund University, Faculty of Engineering LTH, Lund

Download thesis as PDF 

Thesis abstract: The focus of this thesis is on proposing and analyzing a powerful class of codes on graphs?with trellis constraints?that can simultaneously approach capacity and achieve very low error floor. In particular, we propose the concept of spatial coupling for turbo-like code (SC-TC) ensembles and investigate the impact of coupling on the performance of these codes. The main elements of this study can be summarized by the following four major topics.

First, we considered the spatial coupling of parallel concatenated codes (PCCs), serially concatenated codes (SCCs), and hybrid concatenated codes (HCCs). We also proposed two extensions of braided convolutional codes (BCCs) to higher coupling memories.

Second, we investigated the impact of coupling on the asymptotic behavior of the proposed ensembles in term of the decoding thresholds. For that, we derived the exact density evolution (DE) equations of the proposed SC-TC ensembles over the binary erasure channel. Using the DE equations, we found the thresholds of the coupled and uncoupled ensembles under belief propagation (BP) decoding for a wide range of rates. We also computed the maximum a-posteriori (MAP) thresholds of the underlying uncoupled ensembles. Our numerical results confirm that TCs have excellent MAP thresholds, and for a large enough coupling memory, the BP threshold of an SC-TC ensemble improves to the MAP threshold of the underlying TC ensemble. This phenomenon is called threshold saturation and we proved its occurrence for SC-TCs by use of a proof technique based on the potential function of the ensembles.

Third, we investigated and discussed the performance of SC-TCs in the finite length regime. We proved that under certain conditions the minimum distance of an SC-TCs is either larger or equal to that of its underlying uncoupled ensemble. Based on this fact, we performed a weight enumerator (WE) analysis for the underlying uncoupled ensembles to investigate the error floor performance of the SC-TC ensembles. We computed bounds on the error rate performance and minimum distance of the TC ensembles. These bounds indicate very low error floor for SCC, HCC, and BCC ensembles, and show that for HCC, and BCC
ensembles, the minimum distance grows linearly with the input block length. The results from the DE and WE analysis demonstrate that the performance of TCs benefits from spatial coupling in both waterfall and error floor regions. While uncoupled TC ensembles with close-to-capacity performance exhibit a high error floor, our results show that SC-TCs can simultaneously approach capacity and achieve very low error floor.

Fourth, we proposed a unified ensemble of TCs that includes all the considered TC classes. We showed that for each of the original classes of TCs, it is possible to find an equivalent ensemble by proper selection of the design parameters in the unified ensemble. This unified ensemble not only helps us to understand the

When: 2018-06-11 09:15 to 2018-06-11 09:15
Location: Lecture hall E:1406, building E, Ole Römers väg 3, Lund University, Faculty of Engineering LTH, Lund


PhD Dissertation: Verification of wireless communication performance and robustness for automotive applications

Published: 2018-05-31

Author: Mikael Nilsson

Opponent: Jerome Härri (Associate professor)

When: 8 June at 10.15

Loaction: Lecture hall E:1406, building E, Ole Römers väg 3, Lund University, Faculty of Engineering LTH, Lund

Thesis abstract: Today's test methods used for verifying the performance and robustness of automotive applications using wireless communication are often based on field trails, which are time consuming, costly, and not repeatable. Therefore, there is an urgent need for new verification methods that can be performed in lab environment, where the realistic radio propagation environment can be emulated. The telecom industry is using standardized over-the-air (OTA) test methods for verification of their products, e.g., smartphones. In these OTA test methods, different standardized channel models are emulated to reflect different user scenarios, e.g., walking in a city or driving on a highway. One topic in this thesis has been to see if it possible to scale up the used OTA verification methods for smartphones, to a setup where the device under test
(DUT) is a car. Detailed studies have been performed on the OTA mutliprobe setup inside an anechoic chamber, using a complete car as the DUT. The measurements were performed on a single-input single-output (SISO) system at 5.9 GHz, a frequency band used for vehicle-to-vehicle (V2V) communication.

The conclusions we present are that the repeatability is under control for a SISO system and that the desired channel can be emulated. For multiple-input multiple-output (MIMO) systems further research is needed. Emulation of a V2V channel in the OTA test setups requires deep knowledge of the characteristics of the V2V channel, e.g., it could be gathered through measurement based nalysis. In the other research topic, measurement campaigns have been preformed using IEEE 802.11p transceivers (standard for V2V communication) installed in several vehicles, both cars and trucks, a unique campaign in that sense. For the communication links cross all vehicles, estimation of the joint shadowing effects have been possible to make. A cross-correlation model of the large scale fading process is presented for a V2V scenario on a highway. In addition, improved path loss models for both highway and urban scenarios is presented, which consider antenna pattern and other vehicles obstructing the communication.

When: 2018-06-08 10:15 to 2018-06-08 10:15
Location: Lecture hall E:1406, building E, Ole Römers väg 3, Lund University, Faculty of Engineering LTH, Lund


ELLIIT Distinguished Lecture on What We Have Learned About Using Software Engineering Practices in Research Software by Prof. Je

Published: 2018-05-22

Welcome to the ELLIIT Distinguished Lecture on ?What We Have Learned About Using Software Engineering Practices in Research Software? by Prof. Jeffrey Carver on June 4, 13:15.

Title: What We Have Learned About Using Software Engineering Practices in Research Software

Speaker: Prof. Jeffrey Carver, University of Alabama, USA

Location: E:2116, E-huset, LTH, Lund University

Date and time: June 4, 2018, 13:15-14:00

Abstract: The increase in the importance of Research Software (i.e. software developed to support research) motivates the need to identify and understand which software engineering (SE) practices are appropriate. Because of the uniqueness of the research software domain, existing SE tools and techniques developed for the business/IT community are often not efficient or effective. Appropriate SE solutions must account for the salient characteristics of the research software development environment. To identify these solutions, members of the SE community must interact with members of the research software community. This presentation will discuss the findings from a series of case studies of research software projects, an ongoing workshop series, and the results of interactions between my research group and research software projects.

Bio: Jeffrey C. Carver is professor in the Department of Computer Science, University of Alabama. He received the PhD degree in computer science from the University of Maryland in 2003, under supervision of Prof. Victor Basili. His main research interests include empirical software engineering, peer code review, human factors in software engineering, software quality, software engineering for science, and software process improvement. Prof. Carver is editor of the Practitioner's Corner column in IEEE Software, and editorial board member of Computing in Science & Engineering, Empirical Software Engineering (Springer), Information and Software Technology (Elsevier) and Software Quality Journal (Springer). Contact him at carver [at] cs [dot] ua [dot] edu.

When: 2018-06-04 13:15 to 2018-06-04 14:00
Location: E:2116, E-huset Ole Römers väg 3, LTH, Lund University


Swedish Microwave Days

Published: 2018-02-12

The Swedish Microwave Days presents for the 4th time, the GigaHertz Symposium and AntennEMB Symposium into a major joint two-day microwave event, this time in Lund! With joint exhibitions, plenary sessions, invited speakers, and social events the Swedish Microwave Days will be the perfect meeting point for everyone who is interested to learn about recent advances in microwave, millimeter-wave, THz, or antenna technology or to hear about the recent advances in wireless communications, sensor, and emerging applications!?

GigaHertz Symposium

GigaHertz Symposium is a biennial conference in the field of GigaHertz technology. This will be the 14th GigaHertz Symposium after its start in Linköping 1992. The scope is broad, ranging from devices to systems, and from single GHz frequencies up to several THz. The conference is a meeting place for researchers in the field from industry, academia, and research institutes. The format of the conference is a mix of invited talks and regular submitted papers. A number of leading researchers have been invited to give presentations of different hot topics in GigaHertz and TeraHertz technology.

The emphasis of GigaHertz is on new high-speed devices and circuits and their implementation in wireless communication, sensors and fiber optic communication systems. We also welcome submissions in emerging nanodevices, wireless and optical communication and antenna integration. 

AntennEMB Symposium

AntennEMB, is the radio science conference on Antennas and Computational Electromagnetics organized by SNRV (Svenska Nationalkommittén för Radiovetenskap, the Swedish URSI Committee). The AntennEMB has been organized on a regular basis for more than a decade and the last conference was held in Linköping 2016 as part of the Swedish Microwave Days. The format of the conference combines invited key-note talks with original contributions from the conference participants in the form of oral presentations and interactive poster sessions.

The aim is to bring together people from industry, academia and other research oriented organizations with an interest in antennas and computational electromagnetics. The scope of the conference includes the development of computational methods, optimization algorithms and programming techniques, and all types of antenna technology, applications, theory and measurement techniques.

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When: 2018-05-24 10:00 to 2018-05-25 16:00
Location: LTH, Lund, Sweden


IVA-seminarium: LTH öppnar dörrarna för industrin

Published: 2018-04-09

Lunds Tekniska Högskola öppnar sina laboratorier för att fler företag ska ha råd att utveckla nya produkter. Företag som bygger och testar prototyper välkomnas nu till sju laboratorier på LTH. Satsningen förutspås gynna forskningen ? men också Öresundsregionen i stort. 

På LTH finns utrustning och lab i världsklass. Nu lanseras konceptet LTH Open Door för att dessa ska kunna komma fler till nytta. Både startups och etablerade bolag är välkomna. Förhoppningen att denna "dörröppnare" ska kunna bidra till en förenklad innovationsprocess och nya samarbeten.

I nuläget ingår sju lab i projektet: 3D-printlaboratoriet, biomedicintekniklaboratoriet, elektroniklaboratoriet, laserlaboratoriet, nanolaboratoriet, VR-laboratoriet och brandforskningslaboratoriet.

På seminariet så kommer Charlotta Johnsson, vicerektor för Samverkan och Innovation på LTH, att ge en kort introduktion. Därefter så kommer representanter för de olika labben att presentera sin verksamhet. Seminariet avslutas med studiebesök på biomedicinteknik- och elektroniklaboratorierna.

Välkommen till ett seminarium och studiebesök tillsammans med IVA Syd. Seminariet börjar kl 17.00 men varmt välkommen från kl 16.30 då vi serverar kaffe. Observera att antalet platser är begränsat. 


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When: 2018-05-02 17:00 to 2018-05-02 19:00
Location: LTH, E:1406 (bottenvåningen, norrut), E-huset, Ole Römers väg 3, Lund


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