Performance analysis of data transmission in W-CDMA system

We analyze the performance of multiple rejects (MR) ARQ for RLC (radio link control) proposed by 3GPP. The main purpose of MR ARQ is to get efficient use of radio resources at receiver by reducing number of acknowledgements. We analyze MR ARQ and compare its performance with selective repeat (SR) ARQ in the wireless fading channel environment. Based on mathematical analysis and simulation, it is shown that we need to increase the size of buffer for MR ARQ to hold data packets for the period of acknowledgement, and need to increase the size of buffer much more for MR ARQ in the noisier channel environment. It is shown that as the length of period for acknowledgement is increased, we need to increase the size of buffer much more for the saturated throughput. Increasing the size of buffer is needed for the efficient use of radio resources by reducing the number of acknowledgements. Also, the increased delay is another tradeoff.