Improving the Performance of IEEE 802.11 in Wireless Multi-Hop Networks

The IEEE 802.11 MAC Protocol and on demand ad hoc routing protocols (DSR, AODV) have been widely used in experiments and simulations in wireless ad hoc networks. However, previous researches have shown that IEEE 802.11 MAC protocol does not perform well in wireless multi-hop networks because of the interaction between MAC and routing layers. Hidden node problem makes a node fails to reach its adjacent neighbor, thus triggers false route failures in routing layer which greatly degrades the performance of the network. This paper proposes a scheme, named Adaptive Retransmission Control (ARC), to reduce the probability of false route failures. ARC is completely distributed and does not introduce any additional communication overhead. Simulation experiments are conducted to evaluate the performance with and without ARC. Results show the TCP throughput improvement by 5% to 57% under various simulated topology and different mobility.