TCP throughput performance and fairness in wireless networks under spurious timeouts

Large and sudden variations in packet transmission delays are often unavoidable in wireless networks. Such large delays, refer to as delay spikes, are likely to exceed several times the typical network round-trip-time figures, which can cause TCP spurious timeouts. The spurious timeouts lead to unnecessary retransmissions and reduction of the TCP sender´s transmission rate, and degradation of TCP throughput. In this paper we study the effect of delay spikes caused by handover on TCP performance by using three different mobility models. The results show that the throughput of TCP connection over a single bottleneck link is decreased significantly in the presence of delay spikes. Furthermore, it is shown that the fairness feature of TCP is also severely affected in the presence of delay spikes.