lu.se

Elektro- och informationsteknik

Lunds Tekniska Högskola | Lunds universitet

Kalendariumarkiv

2017-05-12 PhD defense by Cezar Zota

Publicerad: 2017-03-23

Date: May 12, 2017 
Time: 10.15 -12.30 
Place: E1406 



 


2017-04-26 Information meeting on project applications to the Knut and Alice Wallenberg Foundation

Publicerad: 2017-03-23

Date: 26 April 2017
Time: 15.00 -17.00 
Location: Pangea, Geologiska institutionen, Geocentrum II, Sölvegatan 12, Lund 
Title: Information meeting on project applications to the Knut and Alice Wallenberg Foundation

Organizers: LTH, Faculty of Medicine, Faculty of Science and Research Services

See more

 

 



 


2017-03-31 PhD Thesis defense by Hemanth Srinivas Prabhu

Publicerad: 2017-02-22

Date: Mar 31, 2017 
Time: 10.15 
Place: E1406



 


2017-03-24 PhD Thesis defense by Rakesh Gangarajaiah

Publicerad: 2017-02-22

Date: Mar 24, 2017 
Time: 10.15 
Place: E1406



 


2017-03-24 Master Thesis presentation by Yaqin Chen.

Publicerad: 2017-03-23

Date: Friday March 24 
Time: 9.15 
Place: E:2349 
Title: Evaluating Off-the-shelf Hardware for Indoor Positioning

Master Thesis presentation by Yaqin Chen.

Supervisors: Fredrik Tufvesson, Peyman Hamed Seyed Hosseini, Sigma Connectivity

Examiner: Fredrik Rusek

 

Abstract

An indoor positioning system (IPS) is a system to locate objects in indoor environments using radio waves, magnetic fields, acoustic, optical and video signals or other sensory information with help of a number of known reference positions. Nowadays, indoor positioning based services are used in a wide variety of areas and indoor positioning is getting considerable attention from both research and industry. Building indoor positioning systems using off-the-shelf hardware can considerably reduce the cost of the system implementation.

In this master thesis, three kinds of off-the-shelf hardware based on Ultra-Wideband (UWB), WiFi and Bluetooth low energy (BLE) technology respectively are exploited to build up indoor positioning systems. Evaluation and comparison of these three systems are performed through a comprehensive study of the related theory, practical experiments and brief study of off-the-shelf hardware.

Commonly used radio positioning technologies and basic indoor positioning techniques are studied as the foundation of the practical experiments. Accuracy, power consumption, cost and ease of deployment are defined as criteria to evaluate and compare the three systems. A systematic method for deploying these three positioning systems for practical experiments is presented and discussed. A trilateration positioning algorithm is implemented for these three systems to estimate positions and compare accuracy. Results from experiments for both line of sight and none line of sight scenarios are given. Results from a brief study of off-the-shelf hardware for a rough qualitative comparison of power consumption and cost of these three evaluated hardware are presented. Furthermore, obstruction experiments were performed to observe influences of the obstacles on accuracy for these three hardware. Finally, suggestions on future work are provided.

The evaluation shows that the UWB hardware performs the best accuracy for indoor positioning, in centimeter order, but it costs more than the WiFi and BLE hardware. The BLE hardware provides worst indoor positioning accuracy, around 4.5 m in average. However, it is the cheapest and most power consumption efficient among these three evaluated hardware. The WiFi hardware is a kind of a trade-off between the UWB and BLE hardware in terms of indoor positioning, giving medium level accuracy, power consumption and cost. The BLE hardware is easier to deploy compared to the UWB and WiFi hardware as BLE devices are smaller size and able to be powered by coin batteries and thus can avoid external physical connections. However, the RSS-based BLE IPS need proper propagation model to estimate distances, which adds extra workload for the deployment compared to the UWB and WiFi IPSs. Obstruction experiments show that obstacles degrade ranging performance greatly for all of these three hardware and influence on the BLE hardware is the most severe.

 



 


2017-03-17 PhD Thesis defense by Farrokh Ghani Zadegan

Publicerad: 2017-02-22

Date: Mar 17, 2017 
Time: 10.15 
Place: E1406



 


Occasion 2: Open lectures with information on The Conversation

Publicerad: 2017-02-06

Date: Mar 02, 2017 
Time: 09.00 - 10.00 
Place: School of Economics and Management, Crafoordsalen, ground floor of the faculty building, Tycho Brahes väg 1, Lund

Presentation of a tool, The Conversation, for all researchers to publish popular science work under their own names. 

 



 


Occasion 1: Open lectures with information on The Conversation

Publicerad: 2017-02-06

Date: Feb 27, 2017 
Time: 15.00 - 16.00 
Place: Palaestra (lower), Universitetsplatsen

 

Presentation of a tool, The Conversation, for all researchers to publish popular science work under their own names. 

 



 


2017-02-23 Presentation by Johan Lundgren

Publicerad: 2017-02-22

Date: Thursday Feb 23 
Time: 15.15 
Place: E:2517 
Abstract

Johan Lundgren will present "Standards in Notation of Mathematics and Physics" where he will talk about how to properly use the most common symbols and quantities in a correct manner based on the not to well-known international standard, ISO-80000. He guarantees that no one follows this standard completely (yet (!)), and that everyone can improve their notation with some easy fixes.

Should this index be italic or roman?
Are units in Roman or italic?
How do I type constants correctly?

 



 


2017-02-14 Licentiate presentation by Dimitrios Vlastaras

Publicerad: 2017-01-17

Date: Feb 14, 2017 
Time: 13.15 
Place: E:2517

Opponent: Dr. Katsuyuki Haneda, Aalto University, Helsingfors, Finland. 
Examinator: Doc. Anders J Johansson 
Supervisor: Prof. Fredrik Tufvesson  
Assistant supevisor: Prof. Ove Edfors 
Title: Vehicular Communication in Obstructed and Non Line-of-Sight Scenarios

Abstract

Since the invention of the first car available to masses, the 1908 Ford Model T, technology has advanced towards making car travel safer for occupants and bystanders. In recent years, wireless communication has been introduced in the vehicular industry as a means to avoid accidents and save lives.

Wireless communication may sometimes be challenging due to obstacles in the physical world that interact with wireless signals. Such obstacles may be dynamic, e.g. other vehicles in the traffic flow, or static, e.g. nearby buildings. Two scenarios are defined to describe those cases. The obstructed line-of-sight (OLOS) scenario is described as the case where a smaller obstacle, usually a vehicle, is placed in-between a transmitter and a receiver. This obstacle usually partially blocks communication and the receiver often moves in an out of the line-of-sight. The non line-of-sight (NLOS) scenario is described as the case where a larger obstacle completely blocks communication between a transmitter and a receiver. An example would be a building at an intersection which shadows the communication between two vehicles. In this thesis the OLOS and NLOS scenarios are investigated from different points of view.

In chapter 2, a road side unit (RSU) that has been constructed and evaluated for integrating older vehicles without wireless communication with newer vehicles using wireless communication is described. Older vehicles are being detected using a universal medium-range radar and their position and speed vectors are broadcasted wirelessly to newer vehicles. Tests have been performed by using the system in parallel with wireless enabled vehicles; by comparing the content in the messages obtained from both systems, the RSU has been found to perform adequately. Accuracy tests have been performed on the system and Kalman filtering has been applied to improve the accuracy even further.

Chapter 3 focuses on the OLOS scenario. A truck as an obstacle for wireless vehicular communication is being investigated. Real life measurements have been performed to characterize and model the wireless channel around the truck. The distance dependent path loss and additional shadowing loss due to the truck is analyzed through dynamic measurements. The large scale fading, delay and Doppler spreads are characterized as a measure of the channel dispersion in the time and frequency domains. It has been found that a truck as an obstacle reduces the received power by 12 and 13 dB on average in rural and highway scenarios, respectively. Also, the dispersion in time and frequency domains is highly increased when the line-of-sight is obstructed by the truck. A model for power contributions due to diffraction around the truck has also been proposed and evaluated using the previously mentioned real life measurements. It has been found that communication may actually be possible using solely diffraction around a truck as a propagation mechanism.

Finally, in chapter 4 a wireless channel emulator that has been constructed and evaluated is described. Modem manufacturers face a challenge when designing and implementing equipment for highly dynamic environments found in vehicular communication. For testing and evaluation real-life measurements with vehicles are required, which is often an expensive and slow process. The channel emulator proposed is designed and implemented using a software defined radio (SDR). The emulator together with the proposed test methodology enables quick on-bench evaluation of wireless modems. It may also be used to evaluate modem performance in different NLOS and OLOS scenarios.

 



 


2017-02-03 PhD Thesis defense by Gabriele Costanza

Publicerad: 2016-12-29

Date: Feb 3, 2017
Time: 10.15
Place: LTH, E-huset, Room 1406



 


Sidansvarig: |