QoS scheduling of mixed priority non-real-time traffic

Non-real-time (NRT) services will constitute a majority of the services provided by third generation systems. The primary QoS parameter for NRT traffic flows is traffic handling priority (THP) which determines the ratios of specified class performance measures. Good system performance is generally defined by low latency and low likelihood of packet loss. The most common measure for latency is average packet delay; however, we show that this measure does not truly reflect the users perceived packet delay. Instead, we introduce effective packet delay which measures delay from the users perspective. Furthermore, we investigate the ability of existing priority and differential service scheduling algorithms to achieve the prescribed THPs for the above performance measures as well as the effect of varying channel bit rate on scheduler performance. Finally, we introduce a new scheduling algorithm, differential effective service, which outperforms existing schedulers with respect to effective packet delay and provide simulation results.