Multistream Proportional Fair Packet Scheduling Optimization in HSDPA

To improve wireless channel capacity, one can reduce radio resource waste through the scheduling of multiple users within a TTI. In interference-limited systems, user selection should be performed carefully, so as to limit interference. In this paper, we present a multistream scheduler, based on a Proportional Fair strategy, for its trade-off between fairness among users and cell throughput. This scheduler is a refinement of an earlier proposal, where the queue length of each user is taken into account, to improve the overall resource efficiency. To avoid significant computations, a heuristic has been developed. The scheduler performance is compared against a multistream Round Robin scheduler and four traditional single user schedulers via computer simulations, in the peculiar case of HSDPA transmissions. Both throughput and fairness gain are highlighted, especially with low users queue rates. A 8% gain in total cell throughout is achieved, while preserving fairness.