On link-level starvation in dense 802.11 wireless community networks

With the growing number of spontaneously deployed WiFi hotspots and home networks, end-users often experience significant performance degradation or even starvation. However, we observe that tuning individual system parameters (channel, Tx power, carrier sense threshold, transmit rate, etc.) is insufficient and may lead to starvation in some cases. In this paper, we develop a comprehensive analytical model to characterize the throughput of individual links in dense IEEE 802.11 wireless community networks that accounts for heterogeneous transmission power levels and CS thresholds, as well as various sources of packet collisions. Based on the insight from the theoretical analysis, we propose a simple identification mechanism that can determine the sources of starvation using local measurements. Both the theoretical model and the identification algorithm are validated using testbed experiments and ns-2 simulations.