Adaptive congestion control mechanism of TCP flows for performance optimization in mobile heterogeneous wireless networks

The transmission control protocol (TCP) provides reliable transport services between end-points and enjoys predominant share as carrier of data traffic over Internet. Last mile wireless links have challenged TCP effectiveness because of fluctuations in link quality and relatively low data rates. These fluctuations cause major performance degradation in terms of reduced throughput, increased retransmission and weak fairness attributes in TCP. A TCP performance in wireless environment has been active research issue. In this paper, we propose Adaptive TCP variant which adjust congestion window adaptively and avoid congestion on network for performance optimization.. The key contribution of the proposal lies in exchanging mobility related messages between sender and receiver on the basis of lower layer triggers to handle timeout related issues in the context of mobility constraints and adjust the congestion window adaptively with respect to link characteristics. This article presents the adaptive congestion mechanism and describes the simulation results of NS 2. The result shows that Adaptive TCP provides the 10.25% to 53.75% improvement in throughput over other TCP variants in dynamically varying wireless networks conditions.