A Low-Complexity Iterative Power Allocation Scheme for Multiuser OFDM Systems

Multiuser orthogonal frequency division multiplexing (MU-OFDM) is a promising technique for future wide-area mobile communications, which can provide scalable high data rate transmission. In this paper, we propose a low-complexity iterative power allocation algorithm with proportional rate constraints. After appropriate subcarrier allocation with equal power distribution, the proposed algorithm can achieve proportional rates among users in a few iterations by determining each user´s power subject to the rate constraints and then equally distributing it to the corresponding subcarriers. Simulation results show that, for the equal rate case, the proposed approach achieves more than 98% of the minimum user´s capacity provided by a near-optimal power allocation algorithm when the number of subcarriers is 128. When the number of subcarriers increases to 1024, the proposed method approaches the optimal performance.