Network Coding For Star and Mesh Networks

This thesis introduces new network coding techniques to improve the file sharing and video streaming performance of wireless star and mesh networks. In this thesis we propose a new XOR based scheduling algorithm for network coding in cooperative local repair. The proposed algorithm commences in three phases. In the first phase, nodes exchange packets availability vectors. These vectors are functions of the probability of correct packet reception over the channel. This is followed by a short period of distributed scheduling where the nodes execute the processing algorithm which tries to minimize the total transmission time. In the third phase, nodes transmit the encoded packets as per the decision of the scheduling algorithm. Simulation results show improvement in system throughput and processing delay for the proposed algorithm. We also study the trade-offs between file sizes, processing delays, number of users and packet availability. In the sequel we display the favorable effects of file segmentation on the performance of the proposed scheduling algorithm. Furthermore, the upper bound on the performance and the analysis of the proposed scheduling algorithm are derived. Also, in this thesis, the effects of random network coding on code division multiple access/time division duplex (CDMA/TDD) platforms for wireless mesh networks are studied and evaluated. A multi-hop mesh network with single source and multiple receiving nodes is assumed. For reliable data transfer, a Selective Repeat ARQ protocol is used. Two scenarios are evaluated for their efficiency. In scenario 1, but not in scenario 2, random network coding is applied to CDMA/TDD wireless mesh networks. The delay and delay jitter for both scenarios are computed. The study also focuses on the effects of uncontrolled parameters such as the minimum number of neighbors and the network connectivity, and of controlled parameters such as Galois Field (GF) size, packet size, number of Walsh functions employed at each node and the Processing Gain. The analysis and simulation results show that applying random network coding to CDMA/TDD systems in wireless mesh networks could provide a noticeable improvement in overall efficiency. We also propose a cross layer approach for the Random Network coded-Code Division Multiple Access/Time Division Duplex (RNC-CDMA/TDD) wireless mesh networks. The proposed algorithm selects the number of assigned Walsh functions depending on the network topology. Two strategies of Walsh function assignments are proposed. In the first, nodes determine the number of their assigned Walsh functions depending on the neighbor with the maximum number of neighbors, which we call the worst case assignment. In the second, nodes determine the number of their assigned Walsh functions depending on the need for each transmission. Simulation results show the possible achievable improvement in the system performance, delay and delay jitter due to cross layer design

Cost- and Energy-Aware Multi-Flow Mobile Data Offloading Using Markov Decision Process

With the rapid increase in demand for mobile data, mobile network operators are trying to expand wireless network capacity by deploying wireless local area network (LAN) hotspots on which they can offload their mobile traffic. However, these network-centric methods usually do not fulfill the interests of mobile users (MUs). Taking into consideration many issues, MUs should be able to decide whether to offload their traffic to a complementary wireless LAN. Our previous work studied single-flow wireless LAN offloading from a MU's perspective by considering delay-tolerance of traffic, monetary cost and energy consumption. In this paper, we study the multi-flow mobile data offloading problem from a MU's perspective in which a MU has multiple applications to download data simultaneously from remote servers, and different applications' data have different deadlines. We formulate the wireless LAN offloading problem as a finite-horizon discrete-time Markov decision process (MDP) and establish an optimal policy by a dynamic programming based algorithm. Since the time complexity of the dynamic programming based offloading algorithm is still high, we propose a low time complexity heuristic offloading algorithm with performance sacrifice. Extensive simulations are conducted to validate our proposed offloading algorithms

Proceedings of the Third Edition of the Annual Conference on Wireless On-demand Network Systems and Services (WONS 2006)

Ce fichier regroupe en un seul documents l'ensemble des articles accéptés pour la conférences WONS2006/http://citi.insa-lyon.fr/wons2006/index.htmlThis year, 56 papers were submitted. From the Open Call submissions we accepted 16 papers as full papers (up to 12 pages) and 8 papers as short papers (up to 6 pages). All the accepted papers will be presented orally in the Workshop sessions. More precisely, the selected papers have been organized in 7 session: Channel access and scheduling, Energy-aware Protocols, QoS in Mobile Ad-Hoc networks, Multihop Performance Issues, Wireless Internet, Applications and finally Security Issues. The papers (and authors) come from all parts of the world, confirming the international stature of this Workshop. The majority of the contributions are from Europe (France, Germany, Greece, Italy, Netherlands, Norway, Switzerland, UK). However, a significant number is from Australia, Brazil, Canada, Iran, Korea and USA. The proceedings also include two invited papers. We take this opportunity to thank all the authors who submitted their papers to WONS 2006. You helped make this event again a success

Device characteristics-based differentiated energy-efficient adaptive solution for multimedia delivery over heterogeneous wireless networks

Energy efficiency is a key issue of highest importance to mobile wireless device users, as those devices are powered by batteries with limited power capacity. It is of very high interest to provide device differentiated user centric energy efficient multimedia content delivery based on current application type, energy-oriented device features and user preferences. This thesis presents the following research contributions in the area of energy efficient multimedia delivery over heterogeneous wireless networks: 1. ASP: Energy-oriented Application-based System profiling for mobile devices: This profiling provides services to other contributions in this thesis. By monitoring the running applications and the corresponding power demand on the smart mobile device, a device energy model is obtained. The model is used in conjunction with applications’ power signature to provide device energy constraints posed by running applications. 2. AWERA 3. DEAS: A Device characteristics-based differentiated Energy-efficient Adaptive Solution for video delivery over heterogeneous wireless networks. Based on the energy constraint, DEAS performs energy efficient content delivery adaptation for the current application. Unlike the existing solutions, DEAS takes all the applications running on the system into account and better balances QoS and energy efficiency. 4. EDCAM 5. A comprehensive survey on state-of-the-art energy-efficient network protocols and energy-saving network technologies

Mobile Ad-Hoc Networks

Being infrastructure-less and without central administration control, wireless ad-hoc networking is playing a more and more important role in extending the coverage of traditional wireless infrastructure (cellular networks, wireless LAN, etc). This book includes state-of the-art techniques and solutions for wireless ad-hoc networks. It focuses on the following topics in ad-hoc networks: vehicular ad-hoc networks, security and caching, TCP in ad-hoc networks and emerging applications. It is targeted to provide network engineers and researchers with design guidelines for large scale wireless ad hoc networks

Satellite Networks: Architectures, Applications, and Technologies

Since global satellite networks are moving to the forefront in enhancing the national and global information infrastructures due to communication satellites' unique networking characteristics, a workshop was organized to assess the progress made to date and chart the future. This workshop provided the forum to assess the current state-of-the-art, identify key issues, and highlight the emerging trends in the next-generation architectures, data protocol development, communication interoperability, and applications. Presentations on overview, state-of-the-art in research, development, deployment and applications and future trends on satellite networks are assembled