Physical Carrier Sensing and Spatial Reuse in Multirate and Multihop Wireless Ad Hoc Networks

Abstract — Physical carrier sensing is an effective mechanism of medium access control (MAC) protocols to reduce collisions in wireless networks, and the size of the carrier sensing range has a great impact on the system performance. Previous studies have shown that the MAC layer overhead plays an important role in determining the optimal carrier sensing range. However, vari-able transmission ranges and receiver sensitivities for different channel rates and the impact of multihop forwarding have been ignored. In this paper, we investigate the impacts of these factors as well as several other important factors, such as SINR (signal to interference plus noise ratio), node topology, hidden/exposed terminal problems and bidirectional handshakes, on determining the optimum carrier sensing range to maximize the throughput through both analysis and simulations. The results show that if any one of these factors is not addressed properly, the system performance may suffer a significant degradation. Furthermore, considering both multirate capability and carrier sensing ranges, we propose to use bandwidth distance product as a routing metric, which improves end-to-end throughput by up to 27% in the simulated scenario. I.