Modeling packet loss probability and busy time in multi-hop wireless networks

Throughput imbalances among contending flows are known to occur when any carrier sense multiple access (CSMA)-based protocol is employed in multi-hop wireless networks. These imbalances may vary from slight difference in throughput to complete starvation in which some flows are unable to acquire channel accesses. The root cause of such imbalances is the lack of coordination when CSMA medium access control (MAC) protocols are employed in multi-hop wireless networks. In this paper, we accurately predict per-flow throughput in general multi-hop wireless networks while addressing CSMA’s coordination problem. Unlike the previous work, our analytical throughput prediction model can clearly differentiate between links interfering from transmission range and carrier sensing range. Modeling of conditional packet loss probability and busy time sensed by each station is critical for per-flow throughput prediction in arbitrary networks. The calculation of both these parameters largely depends on MAC behavior due to geometrical configuration of interfering stations; we accurately compute conditional packet loss probability and busy time based on geometrical configuration of the interfering stations and predicted per-flow throughput. Our analytical results demonstrate improved accuracy, indicate throughput imbalances, and provide better understanding of CSMA-based protocol behavior in multi-hop wireless networks that can be used to design fair, scalable, and efficient MAC layer protocols.