Research On Fairness Based MAC Strategies For Wireless Mesh Networks

Wireless Mesh Network (WMN) is a new type of broadband wireless access network that combines the advantages of WLAN and the Ad hoc Network. It has high reliability and flexibility. In case of the large amount of the occurrence of the multimedia traffic especially the real-time video traffic in future, the legacy IEEE 802.11e access control protocol can no longer meet the traffic QoS requirement or the fairness of transmission in Wireless Mesh Network. In order to solve this problem, it's important to propose some fairness schemes based on IEEE 802.11e.This thesis mainly focuses on how to provide the QoS in Wireless Mesh Network, the topology of which is dynamic and the bandwidth is limited. Aimed at supporting multimedia traffic as well as the network transmission fairness, the thesis analyzes the performance of traditional IEEE 802.11's Qos scheme and investigates the MAC layer protocols for Wireless Mesh Network based on IEEE 802.11e. In this case some fairness schemes are proposed.In chapter one, the structure and contribution of this thesis are outlined. Then, the architecture, the differences between WMN and other networks, the newest applications as well as some advantages of WMN are introduced. This paper briefly introduces how IEEE 802.11e EDCA (a kind of improved EDCA) scheme and compares all the schemes. Then a fairy scheme based on IEEE 802.11e access control scheme is proposed in the third part of the thesis. In chapter 4, we propose a fairy dynamic queue scheduling scheme. Through a number of network simulations, simulation results show that network contention overhead is reduced and the network throughput is increased. The access chance of lower priority traffic is enhanced significantly, and the network transmission fairness is satisfied with this improved scheme. What's more, we propose a traffic-aware scheme fairy access control scheme in chapter 5. Simulation results show that the scheme works out the problem of the bandwidth used by the VBR traffic and the lower priority traffic throughput is increased. At the same time the delay of real-time video traffic is decreased and the network transmission fairness is satisfied with this improved scheme.Finally, the thesis makes a conclusion and looks forward to future reseach work.