Channel based adaptive resource allocation at the MAC layer in UMTS TD-CDMA systems

We propose a scheduling strategy at the MAC level for the TDD/TCDMA UMTS third generation air interface. More precisely, we consider the uplink of a single-cell pedestrian outdoor scenario. Within this context we investigate the advantage of scheduling the different services that can be offered to the system, characterized by different quality and delay requirements, taking both the service priority and the channel state into account. The characteristics of the TDD/TCDMA transmission system, the power control algorithm and a frequency selective fading channel are considered in our approach, which is semi-analytical and allows the evaluation of the statistics of the frame error rate and the average transmitted power per data unit, which is a measure of efficiency from the energy management point of view. The performance of the scheduling algorithm we propose is compared to a more traditional scheduling approach which takes only the priority of services into account