Performance enhancement of TCP on multihop ad hoc wireless networks

It has been found that the throughput performance of TCP controlled file transfers over multi-hop wireless networks can be very poor, and the bandwidth sharing between multiple TCP transfers can be very unfair. We first report our reconfirmation of these simulation results in the context of a string topology network that uses the IEEE 802.11b medium access control protocol, and an ad hoc routing protocol. We then discuss why the performance of TCP is poor in this scenario. Then we propose a simple modification of the 802.11 backoff algorithm that yields a substantial performance improvement in the situations that we have studied.