Throughput analysis of the proportional fair scheduler in HSDPA

High speed downlink packet access (HSDPA) provides increased user data rate by introducing additional functionalities at the Node B, such as fast packet scheduling based on the instantaneous radio link quality. One of the algorithms that is able to provide this capability is the proportional fair (P-FR) scheduler. In this paper we describe an approximate analysis method for the mean throughput of the proportional fair scheduler with two traffic classes. We extend the existing results that are based on the assumption of continuous rate distributions to the more realistic discrete distributions. The analysis with discrete distributions entails two problems that do not appear in the continuous case, namely that the priority of several users can be equal with a non-zero probability and that the sample path of throughputs does not always converge to a mean throughput. The proposed approximate method is evaluated with NS2 simulations.