Assigning and Scheduling Partially Overlapping Channels in Wireless Mesh Networks

The design and the management of Wireless Mesh Networks (WMNs) are currently associated with the most active research area within the current wireless networking paradigms. WMNs inherit features from existing wireless networking technologies such as WLANs, mobile ad hoc networks. Because WMNs are easy to deploy and with low power consumption, there is a phenomenal growing interest in seeing WMNs as the next wireless backhaul networks, and an alternative to the existing wired infrastructure. The earliest development of WMNs had begun with single-channel single-radio mesh networks. This technology then evolved towards multi-channel single-radio mesh networks, and then to multi-channel multi-radio mesh networks. WMNs operate in North America on IEEE 802.11 2.4 GHz spectrum, which provides up to 11 channels. Despite the availability of 11 channels, only 3 (1, 6, 11) orthogonal channels can be used concurrently. The efficiency of multi-channel multi-radio wireless mesh networks can be improved with the increase of the number of channels used concurrently and of multiple radios. In this study, we investigate how to design a scalable channel assignment and a scheduling algorithm, which both exploit partially overlapping channels in order to increase the throughput in comparison with the one that can be obtained only using three orthogonal channels. In order to accurately take into account the radio interferences, we use the physical interference model to estimate the interferences among wireless links. We then introduce the definition of transmission configurations, which are sets of links, which can transmit concurrently. These links can be assigned with channels of overlapping or orthogonal in nature. We then design a TDMA based scheduling allowing a transmission configuration to transmit concurrently in a time slot. Finally, we evaluate all our algorithms through extensive simulations. Our numerical experiments show that we can gain up to 25% for the throughput by appropriately managing all the available channels