An Combined Scheduling Algorithm for HSDPA Mode of TD-SCDMA

In high-speed downlink packet access (HSDPA) mode of TD-SCDMA system, high speed downlink traffic channel and some associated control channels are shared by all user equipments (UEs). This shared mechanism causes feedback problem for scheduling, so some scheduling algorithms (for example proportional fair) are not applicable any more. In this paper, an improved scheme is proposed to accommodate to this condition on the basis that system structure is not modified and for the sake of minimizing performance loss. In the proposed algorithm, proportional fair and round robin are combined so that system can work and throughput can be guaranteed. A numerical simulation platform is established to evaluate system performance. Simulation results show that feedback frequency is of great importance to system throughput, and lower feedback rate may eliminate multi-user diversity with large number of users.