Handoff Performance Enhancement for TCP-based Streaming Services in Heterogeneous Networks

The development and enhancement of wireless communication systems such as cellular network and wireless LAN initiate the interests of heterogeneous networks where mobile users can make use of desirable wireless communication system. Furthermore, streaming services in a mobile environment have much attention with the wider bandwidth of wireless networks. Especially, TCP-based streaming service have more attention rather than UDP-based ones, since then can be used via some wide-accepted TCP-based protocols such as HTTP. However, in heterogeneous networks, the throughput of TCP-based communication is drastically degraded by decreasing of TCP congestion window size because of communication interrupt at vertical handoff. Therefore, QoS requirement of applications is not kept until the congestion window size increases enough again. In this paper, we proposed the method to immediately recover the TCP congestion window size by applying IEEE 802.11e EDCA. It can be implemented without extension of the existing TCP. Finally, we show the effectiveness of the proposed method by simulation experiments.