Effect of the RLC and TNL congestion control on the HSUPA network performance

This paper focuses on the impact of the radio link control protocol (RLC) combined with the Iub congestion control on the performance of high speed uplink packet access (HSUPA) networks. The paper investigates the performance enhancement achieved by the RLC AM (acknowledged mode) with the deployment of the Iub congestion control in the HSUPA network. To show the effect of the RLC AM in the uplink, it was compared against the RLC TM (transparent mode). Although RLC TM is not part of the HSPA specification but the aim of the comparison is to highlight and sustain the advantages gained by deploying the RLC AM. The investigations are carried out for a limited TNL network offering a low Iub link bandwidth (which is usually the case for most operators due to high cost of the Iub link), where RLC AM can effectively work with the TNL congestion control in order to optimize the end user goodput performance and the efficient utilization of the overall network resources. This paper also compares the performance of the RLC AM with two different configurations, one combined with the Iub congestion control and another without the Iub congestion control.