Distributed semi-synchronous channel coordination for multi-channel wireless networks

In multi-channel wireless networks, multi-channel diversity can increase the number of concurrent transmissions and thus improve the throughput performance as data transmission on a wireless channel does not interfere with transmissions on the other non-overlapping channels. However, multi-channel coordination may cause severe performance degradation due to hidden terminals, missing receivers, or broadcast deafness problems if the channel usage information is not properly shared among the neighboring nodes. In this paper, we devise a semi-synchronous multi-channel coordination protocol that enables wireless nodes to: (i) efficiently exchange channel and coordination information, and (ii) reduce the overhead of channel switchings. In the proposed protocol, a rendezvous interval is set up in a distributed manner depending on the traffic rate and pattern, and each node independently switches its channel when it can complete its transmissions and then returns to the control channel within the rendezvous interval. This approach makes all nodes return to the control channel at almost the same time without incurring a severe synchronization overhead. Through subsequent analyses and simulation studies, we show that the proposed protocol effectively reduces the number of channel switchings, thereby achieving higher throughput in various multi-channel networking environments.