Frequency domain near-ML multiuser receiver for MC-CDMA systems

In this paper, a novel simple generalized Chase algorithm (GCA) based multiuser detector (MUD) is proposed for MC-CDMA systems. After getting the initial solution from the front-end frequency domain linear minimum mean-squared error (LMMSE) receiver, different Chase-type algorithms are adopted to extend the potential solution list. Among the list, the candidate which can achieve the minimum distance to the received signal, is selected as the final solution. Both bit- and symbol-level receivers for high level modulation schemes are considered. Compared to the conventional MMSE receiver, the proposed receiver can provide superior performance with little increase in complexity. Moreover, the robustness of the proposed receiver is studied by incorporating a semi-blind subspace based channel estimation.