A distributed channel assignment protocol for rate separation in wireless mesh networks

Wireless Mesh Networks (WMNs) support the cost-effective broadband access for Internet users. Although today’s IEEE 802.11 PHY and MAC specifications provide multi-channel and multi-rate capabilities, exploiting available channels and data rates is a critical issue to guarantee high network performance. In multi-rate wireless networks, high-rate links heavily suffer from performance degradation due to the presence of low-rate links. This problem is often referred to as performance anomaly. In this paper, we propose a Rate-Based Channel Assignment (RB-CA) protocol to alleviate performance anomaly by using multiple channels in WMNs. RB-CA exploits a new metric, called Prioritized Transmission Time (PTT), in order to form High-rate Multi-channel Paths (HMPs). With HMPs, a large volume of traffics can be simultaneously delivered from or to the Internet via multiple non-overlapping channels as well as high-rate links. Extensive ns-2 simulations and experiments in a real test-bed have been performed to evaluate the performance of RB-CA and then we compared it with a well-known existing WMN architecture. Our simulation and experimental results show that RB-CA achieves improved performance in terms of aggregate throughput, packet delivery ratio, end-to-end delay, and fairness.