A cross-layer architecture for effective channel assignment with load-balancing in multi-radio multi-path wireless mesh networks

Wireless mesh networks (WMNs) are a promising technology for providing Internet connectivity to large residential areas. In a typical WMN deployment, end-users access the Internet through a backbone of static routers, which are responsible for traffic forwarding towards the closest Internet gateway (IG). In such a scenario, multiple paths may likely exist between the end-users and the IGs. For this reason, multi-path routing schemes appear as a viable approach to provide higher aggregate throughput, fault-tolerance and load-balancing properties. However, route-coupling problems may occur when the paths are concurrently used and certain nodes on separate paths are within each other's interference range. To overcome this problem, we propose a cross-layer architecture that comprises a novel joint multi-path routing and channel allocation scheme for multi-radio WMNs. The routing scheme discovers multiple node-disjoint paths between a source node (i.e. the end-user) and the gateway node. During the route setup, channel allocation is performed so that nodes on different paths, but within the same interference domain, transmit on different channels. As a result, the effect of route coupling is strongly mitigated. Moreover, we propose a load-balancing scheme, which allows to distribute traffic among the available node- and channel-disjoint paths. The simulation results show that the proposed scheme reduces the end-to-end delay and significantly enhances the system goodput over several network topologies and under different traffic workloads.