HTSMA: A Hybrid Temporal-Spatial Multi-Channel Assignment Scheme in Heterogeneous Wireless Mesh Networks

A number of multi-channel assignment schemes have recently been proposed to improve the throughput of IEEE 802.11-based multi-hop wireless mesh networks (WMNs). In these schemes, channel coordination is done either through time synchronization across all the hosts, or through the use of a dedicated channel for the transmission of necessary control messages. Either way, excessive system overhead and/or waste of bandwidth resource become unavoidable, undermining the overall network throughput. To maximize the network throughput, we propose a synchronization-free, hybrid temporal-spatial multi-channel assignment scheme in a random heterogeneous network requiring only a single radio interface per host. In this scheme, the gateway is allowed to use all the available channels sequentially in a round-robin fashion. This temporal channel assignment approach ensures that all the neighboring hosts that communicate with the gateway directly shall have a fair access to the gateway. The channel assignment for the remaining wireless hosts is based on the geographical location and channel availability (a spatial approach) to avoid the interference within the communication region of each sender host in its transmission time period. Compared with another multi-channel scheme MMAC, extensive simulation results demonstrate that our proposed scheme can improve the network throughput substantially with the acceptable collision ratio.