Performance of multi-carrier CDMA with iterative detection for a Doppler shift channel in a LEO mobile-satellite communications environment

In this paper we consider a matrix algebraic approach to derive the coded multi-carrier CDMA (MC-CDMA) system model for a Doppler shift channel. We derive the effects of Doppler shift in a MC-CDMA system for low earth orbit (LEO) mobile-satellite communications and show the similarity of a MC-CDMA channel model under Doppler shift with that of the asynchronous DS-CDMA channel model. We therefore take advantage of a recently proposed technique that combines iterative decoding and interference cancellation in asynchronous DS-CDMA to reduce the multiuser interference and thereby improve the performance of the Doppler shift channel. We show that the performance approaches single user performance even for moderate signal to noise ratio.