Date Added: Apr 2009
The authors study the spectral efficiency of large random direct-sequence code-division multiple-access systems utilizing Linear Minimum Mean Square Error (LMMSE) channel estimation and iterative Multi-User Detection and Decoding (MUDD). The iterative MUDD based on non-linear data estimation and single-user decoding is considered as a benchmark for the more practical iterative LMMSE data estimator with soft parallel interference cancellation. The results showed that the channel parameters and the choice of error correction code have a great impact on the achievable spectral efficiency. It was also found that for the considered setups, the iterative LMMSE based channel estimator is near optimal for slowly time-varying multipath fading channels.