A flow control scheme for improving TCP throughput and fairness for wireless networks

Most of recent research results on TCP performance in wireless networks have a limitation that they assume a single TCP connection. When multiple TCP connections are concentrated in a base station (BS), it is liable to be a bottleneck and the difference of network bandwidth between wired and wireless links aggravates the situation. The BS experiences frequent congestions and eventually lead to performance degradation. Furthermore, it is difficult to guarantee fairness among multiple TCP connections. To meet both of the challenges, we propose a flow control scheme called feedback-based snoop (F-Snoop). F-Snoop provides the TCP sender with BS buffer state information via TCP ACKs explicitly in real time so that the TCP sender can increase its transmission window size to fill the network pipe, while regulating packet transmission rate to avoid buffer overflow at the BS. The performance is evaluated by simulation using ns-2 and the results show that the F-Snoop not only achieves improvement in throughput but also fairly allocates the available wireless bandwidth to all TCP connections.