Quality of service in Ad Hoc 802.11 networks

This paper presents major quality of service problems in IEEE 802.11 networks. It analyzes unfairness in bandwidth sharing and TCP instability in MAC 802.11. Moreover, differentiation techniques for providing medium access priority are evaluated. Simulation results show that the ad hoc routing protocol has a great influence on unfairness and on the TCP throughput instability due to succeeding routing failures originated by the MAC sublayer. Differentiation mechanism results show that DIFS-based schemes can provide a fine-grained throughput differentiation compared to backoff-based ones. Nevertheless, backoff-based schemes are more effective in providing latency differentiation, which is important for real-time traffic.