Proportional Fair Power Allocation for OFDM-CDM Systems in Frequency-Selective Rayleigh Fading Channels

Abstract

Orthogonal frequency division multiplexing with code division multiplexing (OFDM-CDM) is one of the combined schemes of OFDM and CDMA techniques. The CDM component enables additional diversity in frequency selective fading channels. This paper proposes an optimal power allocation via proposal-fair strategy for the OFDM-CDM-based systems. A zero-forcing beamformer is used at the mobile unit and the basestation optimizes its power allocation to maximize the sum-rate subject to fairness constraints. Two optimization techniques are proposed. Simulation results are provided for typical downlink situation and a fairness index is compared to that of system optimized without fairness request