An Adaptive Resource Allocation Algorithm for Multiuser OFDM

This paper describes a practical and efficient adaptive subcarrier, power and bit allocation algorithm for multiuser OFDM systems. Assuming perfect knowledge of CSI at the transmitter, we look at the problem of minimizing the total power consumption while maintaining individual rate requirements and QoS constraints. We divide the joint allocation into two stages: fast initial allocation and further iterative refinement. An average-SNR approximation is used to determine the subchannel assignment while substantially reducing the computational complexity. The proposed algorithm guarantees improvement through each iteration and converges quickly to a stable suboptimal solution. Numerical results and complexity analysis show that the proposed algorithm offers a beneficial cost-versus-performance tradeoff compared to existing approaches.