Constrained Rate-Maximization Scheduling for Uplink OFDMA

Abstract

In this paper, we study the sum rate maximization algorithms with and without proportional fairness for uplink orthogonal frequency division multiple access (OFDMA). For fair scheduling, we propose a selective multiuser diversity (SMuD) scheme with normalized channel signal-to-noise ratio (n-SNR) ranking for user selection at each carrier to achieve a long term access fairness. To achieve rate maximization without access fairness, we propose a transmission power-SNR-product (PSP)-ranking based SMuD scheme, which takes into account different users' unequal transmission powers and channel SNRs, and provides a near-optimal sum-rate. For both schemes, the transmit power of each user is allocated to the assigned carriers using either equal power allocation (EPA) or waterfilling (WF). Analytical throughput and fairness metrics for both n-SNR and PSP SMuD schemes over Rayleigh channels are derived and verified via simulations. These results put new insight into the achievable uplink OFDMA performance with and without proportional fairness and the effects of various system and channel parameters.