Cross-Layer Resource Allocation via Geometric Programming in Fading Broadcast Channels

In a fading broadcast channel (BC), queue proportional scheduling (QPS) is presented via geometric programming (GP). Given the current queue state, QPS allocates a data rate vector such that the expected rate vector averaged over all fading states is proportional to the current queue state vector as well as on the boundary of the ergodic BC capacity region. One well known throughput optimal policy for a fading BC is maximum weight matching scheduling (MWMS), which maximizes the inner product of the queue state vector and achievable rate vector. Simulation results for Poisson packet arrivals and exponentially distributed packet lengths demonstrate that QPS provides a significant decrease in average queuing delay compared to MWMS. In addition, QPS is shown to guarantee fairness among users in terms of average queuing delay