Truncated power control for improving TCP/IP performance over CDMA wireless links

The issue of the performance degradation of transmission control protocol/Internet Protocol (TCP/IP) over wireless links due to the presence of noncongestion-related packet losses has been addressed with a physical layer approach. The effectiveness of automatic repeat request techniques in enhancing TCP/IP performance depends on the tradeoff between frame transmission delay and residual errors after retransmissions. The paper shows how a truncated power control can be effectively applied to improve that tradeoff so that a higher transmission reliability is provided without increasing the frame transmission delay through the radio link layer and without increasing the energy consumption. An analytical framework has been developed to show the feasibility and effectiveness of the proposed power control. The analytical results, which are carried out assuming a constant multiuser interference level, show that the proposed algorithm turns out to be very effective when the time variability of the channel is high, which-in case of constant interference level-means that the Doppler frequency is high. Simulations carried out in a variable interference scenario show that the proposed strategy is very effective in improving the end-to-end throughput of a TCP connection. Moreover, these improvements are higher when the traffic is more bursty, like in typical Internet data applications such as e-mail and web surfing.