Research On Channel Assignment In Multi-radio Multi-channel Wireless Mesh Network

Wireless Mesh Network (WMN) is a new promising broadband wireless networking architecture, it possesses a high transmission speed, a wide coverage and low cost, WMN is one of relatively competitive solutions to solve ubiquitous last-mile broadband wireless access. The network throughput could be decreased by link interference in the WMN, so it is an efficient way to use non-overlapped channels for date transfer. Each node can be equipped with multiple radis in WMN and different non-overlapped channels are defined in the IEEE 802.11 standards. Research on how to use multi-radio and multi-channels assignment problem and decrease interference and improve the network throughput between wireless links is of great significance.In this paper, considering the problem that the centralized static channel assignment algorithm brings great costs by acquiring the global information of all nodes or link in network, a load aware based distributed channel assignment algorithm (LADCA) was proposed to assign channels to links. According to the conflict between links, the traffic load and data rate of the link, the interference metric between links is defined. The channel assignment algorithm firstly stratifies the network topology structure and then assigns channels according to the priority of layers. In this algorithm, in order to distribute the interference uniformly to the different channel as possible, the links select the channels though greedy strategy. The link always selects the channel that the degree of interference of channel is minimal within the collision domain of links and it satisfies the constraint condition of node interface. According to this selection, the system can avoid the problem that the multi-radio and multi-channel assignment strategy has the hidden problem and channel interdependence problem, and the network throughput can be improved by minimizing the interference between links. This paper also proposes a failure recovery mechanism that supports this algorithm, and this recovery mechanism enables nodes quickly recover from failure, and it is no extra spending. Finally, the simulation results show that LADCA algorithm can reduce the network interference effectively and improve the network throughput and well adapt the network scenes that have multiple radios and multiple channels.