Queue Proportional Scheduling in Gaussian Broadcast Channels

Queue Proportional Scheduling (QPS) assigns each user a data rate proportional to the number of packets (or bits) in that user´s queue. This paper analyzes stability, delay and fairness properties of QPS in a Gaussian broadcast channel (BC). QPS is shown to achieve throughput optimality, and guarantee fairness as well as different priorities among users in terms of average queuing delay. One well known throughput optimal policy for broadcast channels is Maximum Weight Matching Scheduling (MWMS) that maximizes the inner product of the queue state vector and the achievable rate vector. Simulation results with Poisson packet arrivals and exponentially distributed packet lengths demonstrate that QPS provides a significant decrease in average queuing delay compared to MWMS in a Gaussian BC.