Reduced Complexity Subcarrier Allocation Schemes for DFT-Precoded OFDMA Uplink Systems

A resource allocation problem of maximizing total achievable rates for multi-user DFT-precoded orthogonal frequency division multiplexing (OFDM) uplink systems is investigated in this paper. A suboptimal subcarrier allocation scheme is proposed, which uses a proposed spectral efficiency enhancement parameter as an index to assign subcarriers to users. The proposed scheme has a lower computational complexity than that of the existing scheme which is shown to be close to the multiuser waterfilling solution. The simulation results show the proposed suboptimal scheme outperforms the existing scheme. Besides, an iterative subcarrier allocation scheme is proposed to improve the performance.