Chip-level receivers in optical overlapping PPM-CDMA

A chip-level detector for optical overlapping pulse-position modulation code-division multiple-access (OPPM-CDMA) communication systems is proposed. The bit error rate of the proposed system is derived and compared to some traditional receivers under the constraints of fixed data rate and laser pulsewidth. These traditional receivers include OOK-, PPM-, and OPPM-CDMA correlators. The throughput limitations of all these receivers are also presented and compared. Our results reveal that a significant improvement in the performance is gained when using the proposed scheme. A throughput limitation of about 7.5 times greater than that of OOK-CDMA correlator is reported on the average.