Symbol bit-error rate of LMMSE receiver for M-ary QAM in multipath faded CDMA channels

This letter investigates the performance analysis of a linear minimum mean square error receiver for M-ary quadratic-amplitude modulation in multipath fading channels. Both channel gain variances and instantaneous channel gains of the interferers are considered for receiver implementation. Approximate expressions for symbol and bit error rates are derived only when the receiver knows the channel gain variances of the interferers. In deriving the analytical expressions, we exploit large system analysis and results in single-user multipath combining. The receiver performance and the accuracy of the theoretical results are examined via simulations.