Optimizing UMTS link layer parameters for a TCP connection

The last few years have witnessed the overwhelming growth of the Internet as well as the huge emergence of mobile devices. The current trend leads to the convergence of these two worlds. The transmission control protocol (TCP), the dominant protocol for end-to-end reliable data transmission will naturally be broadly used in mobile wireless systems and especially over UMTS. However UMTS also implements its own retransmission mechanism via the radio link control (RLC) protocol that is likely to compete with TCP's. The influence of different RLC parameters has been investigated in order to assess the benefits of the link layer ARQ scheme for different situations. The conducted simulations aim at finding the ideal RLC set of parameters for a TCP based application. They lead to the conclusion that using the RLC acknowledged mode is highly recommended since results show that TCP and RLC retransmission mechanisms hardly ever compete.