TCP-Friendly Rate Control over High-Speed Downlink Packet Access

TCP-friendly rate control (TFRC) is an end-to-end congestion control mechanism, whose goal is to provide rate control for unicast flows in IP networks. The main feature of TFRC is its ability to smoothly adapt the sending rate of a flow to network conditions, while competing for bandwidth with TCP flows in a relatively fair manner. TFRC was designed to offer a more stable sending rate than TCP on wired, best-effort networks, making it suitable for applications like multimedia streaming. This paper presents a simulation study of TFRC over UMTS networks with high-speed downlink packet access (HSDPA). We evaluate the performance of TFRC and compare it with that of TCP, under different scenarios of MAC-layer scheduling, radio conditions and background traffic. Our results show that, in this context, the rate stability of TFRC is not necessarily better than that of TCP, and that the performance of TFRC may be greatly improved by the use of an appropriate QoS scheduling policy for HSDPA.