Channel assignment schemes in Wireless Mesh Networks

Wireless Mesh Networks (WMN) is an emerging wireless network infrastructure, which can provide inexpensive and reliable wireless broadband access services, therefore it has been widely adopted and researched. In a practical WMN, the number of radio interfaces is much more than the number of effective channels, which causes a lot of different links between Mesh routers to operate in the same channel. However, unfortunately, such case will interfere with each other and severely affect the network overall performance. To overcome this problem, one of the key techniques is the channel assignment which can effectively improve the duplication of scarce radio spectrum, thereby increasing network throughput. Some researchers have divided the channel assignment into three main categories: fixed, dynamic and hybrid, depending on the frequency with which the channel assignment scheme is modified. According to this classification, it is hard to identify which are the major factors to affect network performance. In this paper, we will first investigate the unique constraints of WMN´s channel assignment, such as connectivity, interference and flow patterns. According to these key constraints, we divide the channel assignment schemes into four categories: connectivity, minimize interference, flow pattern and hybrid interference with flow pattern. Then we will respectively introduce the most popular schemes of different category. In final we will analyze and compare the performance of different schemes and make a conclusion.