MC-CDMA with SIC: power control by discrete stochastic approximation and comparison with OFDMA

Orthogonal frequency division multiple access (OFDMA) and multicarrier code division multiple access (MC-CDMA) are possible candidates for the next generation of mobile wireless systems. However, when applied to an uplink broadband communication, MC-CDMA suffers from multiuser access interference, which can be reduced by using successive interference cancellation (SIC) at the base station. With this regard, here we propose an optimization of the MC-CDMA receiver that jointly determines power control and user detection ordering based on a discrete stochastic approximation algorithm. For OFDMA, we consider instead interleaved transmission and optimization of transmission power for each user. A comparison of OFDMA and MC-CDMA with SIC is then given in a multiuser uplink scenario in terms of sum-power for a required signal to noise ratio at the detection point.