Enhancing MAC Coordination to Boost Spatial Reuse in IEEE 802.11 Ad Hoc Networks

In a wireless ad hoc network where multi-hop traffic dominates the network, spatial reuse has an enormous impact on the network performance in terms of end-to-end throughput and delay characteristics. In this paper, we investigate the MAC coordination of persistent flows in 802.11 ad hoc networks and point out that the aggressive behavior of 802.11 MAC can throttle the spatial reuse and reduce bandwidth efficiency. We thus propose an adaptive layer-2 pacing scheme fully compatible with 802.11 MAC using explicit MAC feedback to balance the transmissions on adjacent nodes. By promoting MAC coordination, our scheme can assist the MAC to operate around its saturation state while minimizing resource contention. Experiment results demonstrate that our scheme significantly outperforms the original 802.11 MAC by boosting the throughput while still maintaining latency at a low level.