Performance analysis on the radio link control protocol of UMTS system

Radio link control (RLC) is a layer 2 protocol used in the UMTS 3G cellular systems for error recovery and flow control. It is close to the selective repeat automatic repeat request (SR-ARQ). Different setups of the RLC parameters such as transmit window size, receiving window size, periodic poll timer, poll timer, and poll prohibit timer can have significant impact to the overall RLC performance. The configuration and optimization of RLC parameters are critical to ensure that precious radio resources are fully utilized. We explore the error rate, the RLC round trip time (RTT), and the TCP flow control impact to the RLC transmit window size selections. Simulation results are presented to demonstrate how the transmit window size impacts the RLC throughput and delay performance.