Efficient power and subcarrier allocation for OFDMA-based relay networks

This paper investigates OFDMA downlink resource (spectrum and power) sharing algorithms for fixed relay stations. Iterative waterfilling is used in the power allocation process and shown to result in an optimal power allocation solution for multiple-relay networks. Iterative waterfilling is then developed with a power reallocation process to achieve more efficient spectrum utilization. Furthermore, joint subcarrier and power allocation algorithms are proposed with and without consideration for multiuser fairness. Simulation results show that iterative waterfilling can significantly improve the system capacity. The proposed joint allocation algorithm achieves gains of up to 21% in system capacity compared to iterative waterfilling. The joint allocation algorithm with fairness is shown to degrade system capacity, however fairness is important in a multiuser network.