MMSE/PIC multiuser detection for DS/CDMA systems with inter- and intra-cell interference

This paper analyzes combinations of the linear minimum mean square error (M MSE) detector and a nonlinear parallel interference canceller (PIC) for mul tiuser code-division multiple-access (CDMA) detection. Both the case where all users' codes are known at the receiver and the case where only some cod es are known are considered, An upper bound acid an approximate formula for the error probability are derived acid verified through simulation. It is shown that the combined MMSE/PIC detector can have a considerable performan ce gain over the MMSE, It is also shown that while the MMSE detector is sen sitive to large code cross-correlation values, the combined MMSE/PIC detect or is robust to code cross correlations. Finally, use of the MMSE/PIC detec tor for cellular systems with both inter- and intra-cell interference is co nsidered.