Channel efficiency-based transmission rate control for congestion avoidance in wireless ad hoc networks

If the transmission rate of transmission control protocol (TCP) does not match that of the medium access control (MAC) protocol in wireless ad hoc networks, it causes network congestion and network performance degradation. This letter proposes a new mechanism to feed back the real channel efficiency of MAC protocol to TCP. Comparing the real channel efficiency in MAC protocol with the virtual channel efficiency in TCP, we can adaptively control the transmission rate in TCP by using the congestion window and the flow of TCP ACKs, in order to alleviate the load of MAC protocol before a congestion event occurs and to enhance the network performance. Simulation results show that the proposed mechanism outperforms 802.11 DCF in terms of throughput and delay.