Improvement of parallel interference cancellation technique with hard limiter for DS-OCDMA systems

In direct sequence optical code division multiple access system (DS-OCDMA), one of the principal limitations is due to unipolar coding which introduces multiple access interference (MAI). To mitigate MAI, we have applied a parallel interference cancellation technique (PIC) to remove non-desired users´ contribution. We study in this paper, the performances of the PIC improved by hard limiters (HL) placed either before the non-desired users receivers (HL+PIC) or before the desired user receiver (PIC+HL). We develop the HL+PIC and PIC+HL theoretical error probability expression, and show the performances improvement due to such receivers