Partially Overlapping Channel Assignment in Multi-Radio Multi-Channel Wireless Mesh Networks

Abstract

Multi-radio Multi-channel (MRMC) Wireless Mesh Networks (WMNs) have made rapid progress in recent years to become a preferred option for end users due to its reliability, scalability and extending the network connectiv- ity on the last mile. Although WMNs have already been deployed but still the capacity of WMNs is limited due to non-coordinated interference (nCO) among channels. To minimize non-coordinated interference among channels and maximize network capacity; channel assignment has always been a key issue in WMNs. Assigning IEEE 802.11b non-overlapping or Orthogonal Channels (OCs) minimize channel interference but they constraint network capacity as they are limited in number and lead to co-channel interference. On the other hand channels whose spectrum interferes with each other are considered as partially overlapping channels in IEEE 802.11b. These partially overlapping channels are not used for transmission as they result in transmis- sion losses due to adjacent channel interference. Recent studies have shown that Partially Overlapping Channels (POCs) are not harmful and they can be used to further improve network performance and can utilize IEEE 802.11b spectrum more e ciently. In this thesis, we propose an optimization model that maximizes network capacity and minimizes non-coordinated interference using both non-overlapping and partially overlapping channel assignment in MRMC-WMNs. We also propose an infrastructure heuristic channel assign- ment algorithm POCA (Partially Overlapping Channel Assignment) where a central node keeps and distributes all the channel assignment information. The proposed model assigns both non-overlapping and partially overlapping channels and nds the optimum channel assignment strategy. Simulation results show that POC assignment performs 17% better than traditional non-overlapping channel assignment in sparse WMN topologies where the non-coordinated interference is high. For dense WMN network environments, where the non-coordinated interference is not high, POC performs 9% better than OC assignment.