Joint scheduling and power allocation in multi-channel access point networks under QoS constraints

We consider the joint scheduling and power allocation problem for uplink transmissions in a multichannel access point network, and develop solutions to achieve the maximum system throughput under QoS constraints for each user. In this frame-based multi-channel OFDM system, our goal is to determine when in the frame and on which channels each user should transmit, and how the power of each user should be split across the channels it uses. Our goal is to maximize the overall effective data rate in the network, taking into account variations in channel rates across channels as well as users, while satisfying minimum rate constraints for each user. Although this problem is in general a complex non-linear mixed-integer optimization question, we show that the optimal schedule and power allocation can be computed in polynomial time under a high SINR approximation. Finally we propose and evaluate several simple heuristics for this problem, and show that some of these attain a performance that is very close to the optimum, at fairly low computational cost.