Channel quality based adaptation of TCP with loss discrimination

TCP responds to all losses by invoking congestion control and avoidance algorithms, resulting in degraded end-to-end performance in lossy environments. In recent years, two approaches have been taken to improve the performance of TCP in such networks. One is local retransmission and the other is end-to-end control. These schemes either impose a heavy computational burden on base station, or cannot achieve both efficient bandwidth usage and fairness between flows because they cannot distinguish the flows on low quality wireless links from flows on high quality links. In this paper, we present a new wireless TCP protocol-End-to-end Link State Aware TCP (TCP-ELSA)-that adjusts the sending rate of a TCP flow according to the wireless link quality, but still provides good congestion control when congestion-related losses occur. The aim of TCP-ELSA is to adapt the sending rate of TCP to the link quality so that the efficiency of bandwidth usage is increased. We present simulation results that demonstrate the effectiveness of TCP-ELSA in various scenarios.