(A) multi-channel TDMA MAC protocol for supporting QoS over multi-hop wireless mesh networks

Abstract

Wireless mesh networks (WMNs) have received wide attentions from researchers because it has high potential to be a future network platform. However, there are many issues and supporting quality of service (QoS) over wireless multi-hop is one of them. The end-to-end delay increases and the throughput degrades significantly over multi-hop wireless links. To tackle the QoS issue, researcher proposed TDMA based control to minimize the end-to-end delay. Some researchers proposed an optimization based time slot allocation algorithm to minimize the maximum delay. The algorithm is limited in that it works for only single channel networks with a single gateway. On another hand, more and more mesh routers are equipped with multiple radios to exploit multiple channels. Multiple channels systems have been proposed to increase system capacities. Some researchers proposed a channel allocation algorithm called ‘Distance-1’ to increase the system capacity. Even though the idea is very novel, their objective is not minimizing delay. In this thesis we propose several flow-based MAC protocols that can help to handle the problems of delay and throughput over multi-hop efficiently. First, in Chapter 1 we introduce basic knowledge of Multi-hop Wireless Mesh Networks, and point out its QoS issues with current solutions. In Chapter 2, We do a brief survey about the state-of-the-art solutions for Multi-channel and time slot assignment that are related to our works. We introduce our first solution to reduce the delay over multi-hop in Chapter 3. In this chapter we proposed a simple but efficient fast-forwarding MAC protocol called a Flow-based MAC protocol. Since the first solution base on 802.11 standards with CSMA access method and works only with single channel, in Chapter 4 we extend it to multiple-channel and use TDMA based to schedule channel access right for wireless devices in a single collision domain. However almost current wireless networks are multiple collision domains...