A Coordinate-Based Approach for Exploiting Temporal-Spatial Diversity in Wireless Mesh Networks

In this paper, we consider the problem of mitigating interference and improving network capacity in wireless mesh networks from the angle of temporal-spatial diversity. In a nutshell, while the achievable throughput on a multihop wireless path is limited by intra-flow interference, the overall capacity of a multihop wireless network can be increased by exploiting temporal-spatial diversity of concurrent transmissions that exist among a number of wireless links. Connections that are routed along multihop wireless paths can be scheduled to take place simultaneously if their transmissions do not interfere with each other (significantly). To make a case of exploiting the temporal-spatial diversity to improve network capacity, we focus on transporting downstream traffic at gateway nodes with Internet access. We propose to construct, based on measurements of received signal strengths, a virtual coordinate system that is used to determine the sets of paths along which transmissions can take place with the least inter-flow interference. Based on the sets of non-interfering paths, the gateway node then determines the order with which a gateway node schedules frames of different connections to be transmitted. Through extensive simulation (with real-life measurement traces on an operational, city-wide wireless community network), we show that the downstream throughput of a gateway node in a wireless mesh network can be improved by 10-35 % under a variety of network topologies and traffic distributions. This, coupled with the fact that the proposed approach requires only minor code change in the gateway nodes and does not require any additional hardware, makes it a viable option to improving network capacity in existing wireless mesh networks.