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S Technische Informatik - Technologies of Wireless Networks

Lecturer: Jochen Schiller, Stephan Schröder, u.a.
Location: K60
Time:

ECTS-credits: 4 (2 SWS)
Prerequisites: Vordiplom or B.Sc., basic knowlegde in telematics

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Content

This seminar is a block seminar, i.e. at the end of the semester, there will be two days when all talks are given in a block. During the semester, there will be deadlines for status reports, but no meetings of the complete seminar group.

Students participating will give a talk and write a report (12 pages). Besides that, they will review one or two reports written by other students and prepare questions to be asked after the corresponding talk. This is to stimulate discussions after the talks and make the seminar more worthwhile.

Schedule

Attention: Students have to meet all deadlines listed in the timetable. Otherwise, she/he will lose the right to take part in the final presentation.

Topics

Advisor: Michael Baar (Seite)

RIME Stack Architektur
Communication protocols for wireless sensor networks are as manifold as the potential applications. The RIME stack of the Contiki operating system tries to serve as a universal platform offering a number of network primitves to build up high level protocols. Analyse the stack's architecture, features and primitives and document it in a concise manner (e.g. feature tables, graphs, interfaces, data flow).
Assigned to: Christian Rotar (report)

Current Approaches to Opportunistic Routing in MANETs
In mobile ad-hoc networks setups where network links are unstable, highly variable and often not available at all standard routing protocols do not work efficiently or not at all. Examples of such setups are car networks or animal monitoring. A class of routing protocols which deal explicitly with these setups is called "opportunistic routing". Survey current state-of-the-art approaches of opportunistic routing protocols and analyze their features, limitations, strength and weaknesses.
Assigned to: Maxim Schaubert (no report)

Tracking in Sensor Networks
Many different sensors provide data that can contains information on a nodes position. Most readings provide only relative information or merely hints. Examples are current GSM network cell, GPS, acceleration, heading, movement, distance estimation to moving or fixed points, proximity to other devices, common environmental readings, air-pressure, … Statistical methods, commonly used in robotics, can help to fuse all this input to a number of probable positions. Common statistical approaches include Kalman and particle filters which are limited their ability to include numerous facts into the calculation. Survey state-of-the-art approaches that overcome these limitations.
Assigned to: Annika Gellert (no report)

Advisor: Bastian Blywis (Seite)

Embedded Systems in Automotive Domain
Cars and trains manufactured in the last 2 to 3 decades could be classified as mobile computers. They are stuffed with various sensors, networks and processing units. Safety is a prime directive in the automotive industry. Therefore software development is based on a multitude of ISO and IEC standards (e.g. ISO TS 16949, ISO 9001, ISO 26262, etc). Try to give an overview of the used technologies, protocols and their applications (e.g. fieldbusses, driver assistents, etc), as well as how the safety concerns and regulations influence the software development. Can wireless communication be considered an alternative to the mostly cable bound implementations in this critical domain?
Assigned to: Stefanie Dourvos (no report)

Data Compression Techniques
Data that has to be send wireless requires a significant amount of energy. Sending just 1 bit might be as much as 1000 times as costly as computing a single instruction. To minimize the energy (lossless) compression algorithms may be used. But as wireless sensor networks are resource restrained systems how can this be achieved? In what kind of scenarios and applications is a lossy compression acceptable? What about compression of locally stored data or even program code?
Assigned to: Ramin Baradari (report)

MANET Mobility Models
In MANET simulations node movement is often randomized. In real world scenarios however the motion follows distinct patterns: Nodes move in groups, the density fluctuates over time or heavy frequented paths are distinguishable. Give insight into the various mobility models and try to answer how the fact of time-variant non random movement patterns influences routing algorithm design in MANETs. Do these models represent realistic scenarios at all? What's still missing? Could a MESH network be dynamically formed by a service running on some selected nodes to simplify routing?
Assigned to: Xiaosen He (report)

Advisor: Freddy Lopez Villafuerte (Seite)

Analysis of advantages and weakness using RSSI for Localization
The localization problem is an open research problem in Ad hoc Wireless Sensor Nodes. One of the most recurrent methods in a wireless sensor network is using the received signal strength. With this seminar topic you will show the problems to do localization using RSSI values and if this approach has future expectative for ubiquitous devices.
Assigned to: Michael Zuberbier (no report)

Using Wireless Sensor Networks to follow a Mobile Node
An important issue in the surveillance problem is the detection and tracking of intrusion. There are methods that could be implemented in a central or distributed manner. We are interesting in the techniques that are appropriated for small devices with limited computational power and limited memory without specialized hardware. With this subject, the student has the opportunity to find and classify approaches to follow a Mobil node on Wireless Sensor.
Assigned to: Christian Völzke (report)

Mobil Nodes and tags in practical applications
In the area of the location-sensing problem new projects and enterprises have appeared. In this seminar topic, the student will find and describe the different ways to follow a tag or sensor through practical applications from different enterprises. The work includes the searching of enterprises that make tracking with small wireless devices.
Assigned to: Florian Hinz (report)

Advisor: Abd Al Basset Al Mamou (Seite)

MADPastry and Virtual Ring Routing (VRR): Overlay routing approaches in Mobile Ad hoc networks based on Distributed hash tables DHTs
In the recent years, Mobile ad hoc networks (MANET) became the most attractive research area in the wireless communication field. These networks can be formed “on the fly” without any preconfigured infrastructure. Nodes forms the network by communicate each to other. The good advantages of ad hoc networks that nodes are dynamic and any node can leave the network or appear at any time. These advantages, in addition to the resource limitations (energy, unreliable wireless communication) pose a big challenge in term of routing. A lot of routing protocols has been developed to improve the routing performance in MANETs. MADPastry and VRR are two examples of overlay routing that use the DHT concepts in the wireless filed.

This seminar will look at the following issues:
1. An overview to MANETs.
2. A description of MADPastry and VRR (How they operate) and what are the difference between them.
3. Evaluation of their performance.
The seminar will not consider specific issues, because this is a huge topic on its own.
Assigned to: Zehe Wu (report)

Quality of Service (QoS) in Wireless sensor networks
Wireless Sensor Networks (WSNs) are a relatively new application of ad-hoc networks. They consist of sensing devices of limited resources. The challenges in WSN usually stem from the limited resources (processing power, transmission bandwidth, memory, battery and etc.). Energy can be the most limiting factor in sensor nodes. As a result, it will influence the overall quality of their services through the network layers . The goal of this seminar topic is to study the problem of maintaining the quality of service above the routing layer through studying and analyzing the “QoS Dynamic routing protocol” .

This seminar will look at the following issues:
1. An overview to QoS in WSNs.
2. A description of QoS Dynamic routing protocol
3. Performance evaluation.
Assigned to: Marc Meyer (no report)

Security in wireless sensor networks
Wireless sensor networks are kind of Ad hoc networks that operate without infrastructure. Security issues in ad hoc networks are relatively similar to those in sensor networks. The secure routing protocols in Ad hoc networks are based on key cryptography but it’s so much expensive for sensor nodes. SNIPS and µTESLA has been proposed as security protocols for WSNs. The goal of this seminar topic is to study the problem of security in WSNs by studying and analyzing the mentioned protocols.

This seminar will look at the following issues:
1. An overview to security in WSNs.
2. A description of SNIP and µTESLA (How they operate) and what are the difference between them.
3. Performance evaluation.
Assigned to: Pascal Gleske (no report)

Advisor: Stephan Schröder (Seite)

Virtual Memory for Sensor Nodes
Sensor nodes are designed to work with minimal hardware. Nonetheless application programers like not worrying about space requirements off their code. Especially if dynamic memory allocation is involved. Therefore Virtual Memory techniques have been adapted to work on these devices. The aim of this topic will be to present several approaches of virtual memory for sensor nodes.
Assigned to: Frank Viernau (no report)

Providing Sensor Nodes with Memory Protection
Sensor Nodes due to their minimalistic approach rarely offer Memory Protection. Therefore often neither OS kernel nor applications are shielded against illegal operations of another applications which lowers the reliablity of these nodes considerably. That's why Memory Protection has been adapted and applied to sensor nodes in several projects which should be presented here.
Assigned to: Sven Ketelsen (report)

Enlarging Sensor Node memory
Sensor Nodes only own very limited memory space. This is a severe constrain for application developer. In order to enlarge the addressable memory space several caching strategies have been developed which should be presented here.
Assigned to: Rupert Burchardi (report)

Advisor: Kirsten Terfloth (Seite)

Domain Specific Languages for Wireless Sensor Networks
Due to the distribution of nodes in the environment and the embedded nature of devices, application development on top of wireless sensor networks (WSN) is still a time-consuming and cumbersome task. Lately, several so called 'domain specific languages' (DSL) have been proposed to tackle this problem at the language level by encapsulation of typical WSN actions as language primitives. The goal of this topic is to examine some representative languages introduced for WSNs, categorize the level of abstraction they provide and critically evaluate their applicability, advantages and shortcomings.
Assigned to: Frank Bourier (no report)

Towards efficient index structures for flash-based sensor devices
Sensor nodes that are to be deployed in an environment usually rely on flash memory for local data storage. With its characteristics such as constraints on the number of write accesses and different granularities for read and write access it imposes new challenges for efficient data storage and retrieval. The goal of this work is to examine popular flash memory structures targeting the wireless sensor network domain, analyze advantages and shortcomings of current solutions and provide an evaluation on their performance and field of application.
Assigned to: Stefan Pfeiffer (report)

Next-generation middleware for Wireless Sensor Networks
A tremendous amount of solutions to provide a middleware abstraction layer for wireless sensor networks have been proposed in the past years. Nowadays, it is extremely interesting to see how these approaches may be grouped by the different core elements they propose a middleware should supply for application developers. The goal of this work is two-fold: First of all, an overview of representative approaches along with their view on what characteristic features WSN applications have, shall be provided. Secondly, a catalogue of common metrics to evaluate middleware approaches, both qualitatively and quantitatively, has to be established and discussed thoroughly.
Assigned to: Sebastian Volkmann (no report)

Advisor: Georg Wittenburg (Seite)

Practical Approaches to Service Placement in MANETs
Service placement deals with selecting which node in a network is most suitable for hosting a service that responds to queries from other nodes. Optimally placing services reduces network traffic and improves connectivity between clients and servers. Practical approaches to service placement commonly employ heuristics based on information gathered from nodes in the neighborhood of the current host. Some heuristics are tailored to the specific application, e.g. coverage, topology or group mobility, and are thus not applicable to general-purpose service placement. The goal of this project is to summarize recent practical approaches to service placement in MANETs, evaluate in detail their strengths and weaknesses, and discuss the question in how far they are applicable to general-purpose service placement.
Assigned to: Lars Rieche (no report)

Theoretical Approaches to Service Placement in MANETs
Theoretical approaches to service placement (introduced above) can be largely considered applications of facility location theory from the field of operations research. They either solve the NP-hard uncapacitated facility location problem with traditional algorithms on a central node after collecting the necessary information from the network or use distributed iterative approximations. It is however questionable whether the theoretical models adequately capture all the intricacies of real-world MANETs. The goal of this project is to summarize recent theoretical approaches to service placement in MANETs, evaluate in detail their strengths and weaknesses, and discuss the question in how far they are applicable to real-world MANETs.
Assigned to: Axel Fiebelkorn (report)

Accuracy in Wireless Network Simulation
In the field of MANETs, network simulators are commonly used to evaluate properties of software components or the network as a whole. Their advantages in reduced experimental overhead, flexibility, and repeatability come at the expense of questionable credibility of the results. To address this deficiency, several experiments have been conducted that aim to verify the accuracy of different simulation models. The goal of this project is to summarize recent work on verification of simulation models, evaluate the impact these results have on simulation-based research, and to discuss the question in how far simulations can be trusted.
Assigned to: Sebastian Stumbek (report)

Literature

© 2009 Freie Universität Berlin, AG CST

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