Cluster-based channel assignment in multi-radio multi-channel wireless mesh networks

In a typical wireless mesh network (WMN), the interfering links can broadly be classified as coordinated and non-coordinated links, depending upon the geometric relationship. It is known that compared to coordinated interference, the non-coordinated interference result in significantly lower throughput and an unfair capacity distribution amongst the links. However, identification of non-coordinated interference relationships requires that each node is aware of the precise location of its neighbours, which is impractical. In this paper, we propose a novel two-phase cluster-based channel assignment scheme (CCAS) that minimizes both non-coordinated as well as coordinated interference without requiring the nodes to be aware of the location of its neighbours. CCAS logically partitions the network into non-overlapping clusters. The links within each cluster operate on a common channel which is orthogonal to that used in neighbouring clusters, thus eliminating non-coordinated interference. The inter-cluster links are assigned channels such that any non-coordinated interference that they introduce is minimized. The second phase of CCAS minimizes the coordinated interference by exploiting the channel diversity to sub-divide each cluster into multiple interference domains, thereby increasing the capacity of individual links. Simulation-based evaluations demonstrate that CCAS can achieve twice the aggregate network goodput as compared to existing channel assignment schemes, while ensuring a fair distribution of capacity amongst the links.