Multi-channel MAC protocol for wireless sensor networks: A schedule-based approach
Wireless mesh networks (WMNs) have emerged as a key technology for next-generation broadband wireless access. While benefiting from larger coverage, WMNs also suffer from some scalability problems in terms of throughput, delay, and packet delivery ratio faced by all multi-hop wireless networks. Using multiple channels is a cost-effective solution to these problems. In this paper, we propose a channel management protocol for multi-channel, single-radio 802.11-based wireless mesh networks. In such an environment, two issues should be addressed: channel assignment and channel switch scheduling. Therefore, most existing multi-channel solutions involve a channel assignment scheme and a scheduling scheme to determine nodes' behaviors at different times. However, we observe that channel switching of some mesh points may not be necessary under this environment. In fact, even without channel switching, the benefit of using multiple channels (spatial reuse) can still be achieved. In this work, mesh points are divided into two sets. Those in the first set will be assigned channels and stay in the assigned channels to transmit/receive packets. On the other hand, those in the second set will switch to proper channels dynamically. With this design, a lot of channel switching overheads (switching delay, synchronization drift, etc.) can be mitigated. Extensive simulations are conducted to verify the efficiency of the proposed protocol.