TCP congestion control based on accurate bandwidth-delay product in wireless Ad hoc networks

Bandwidth-delay product (BDP) is an important indicator of the network capacity and usually used to measure the quality of a connection. In wireless ad hoc networks over IEEE 802.11, packets may be blocked due to link layer contention, and delay triggered by the contention called contention delay has been revealed has nothing to do with BDP. BDP in wireless ad hoc networks has been studied a lot to improve the transmission control protocol (TCP) performance, however, in the calculation of BDP, most of the previous studies neglected to remove the contention delay and thus obtained an overestimated value which may cause congestion window (CWND) overshooting problem. In this paper, we propose a new method to accurately measure the congestion delay which is the effective “delay” of BDP and calculate more accurate BDP. Then, based on the BDP, we set suitable congestion window limit (CWL) to alleviate the CWND overshooting problem and enhance TCP performance. Simulation results show that TCP with CWL based on our accurate BDP works more efficiently.