Fast and efficient power and rate allocation for multiuser OFDM downlink

Adaptive power and rate allocation for multiuser orthogonal frequency division multiplexing (OFDM) has been shown to improve the system performance significantly. In this paper, a group of resource allocation methods with low complexity for multiuser OFDM downlink is presented. The proposed methods initialize subcarrier assignments for users independently, which may result in conflicts on subcarriers. Following processes are designed to resolve such conflicts, where the output is further improved by simply sorting the subcarriers with conflicts according to appropriate criteria. Simulation results show that the best proposed method has less than 4% performance degradation with up to 95% complexity reduction compared to a newly suggested reference algorithm.