Optimizing Aggregate Throughput in 802.11 Networks through Balancing Spatial Reuse and Transmission Rate

Traditional medium access control (MAC) protocols utilize temporal mechanism to do contention resolution. This paper explores an alternative approach by adapting the space occupied by a transmission to resolve contention. Each successful transmission in a wireless network needs to occupy a certain part of space in which there are no other simultaneous transmissions. The size of the space occupied depends on the transmission rate and it consequently determines the level of spatial reuse. To optimize the aggregate network throughput needs to balance the transmission rate and the level of spatial reuse. This paper firstly derives the optimal transmission rate by analyzing the relationship between the transmission rate and the occupied space size, then a distributed algorithm is proposed to achieve the optimal spatial allocation approximately through tuning the carrier sense threshold and the transmission rate. Simulation results show that, the distributed algorithm works well in balancing the transmission rate and the level of spatial reuse, and the aggregate network throughput can approximate the theoretical one and is higher than that can be gained by other similar algorithms.