An analysis on partial pic multi-user detection with lms algorithms for cdma

Abstract

In the partial parallel interference cancellation (PPIC) scheme for direct-sequence code-division multiple-access (DS-CDMA) communication systems, the partial cancellation weight (PCW) does not give us any idea about the correctness of the bit-decision in the previous stage. However, the PCW can be updated by the least-mean-square (LMS) algorithm and may turn into the negative side as the bit-decision error occurs in the previous stage. Therefore, in this paper, we investigate the property of the PCW based on the LMS algorithms. Furthermore, with the maximum a posteriori probability (MAP) detection criterion, an optimal threshold for the adaptation PCW is found to judge the correctness of the bit-decisions and get a mount performance improvement.