In this paper, an optical code-division multiple-access (OCDMA) system employing overlapping pulse-position modulation (OPPM) is proposed to support multimedia services with different bit-rate and quality-of-service (QoS) requirements in OCDMA networks. Both wrapped OPPM (WOPPM) and unwrapped OPPM (UOPPM) are considered. The proposed system achieves multirate and multi-QoS transmission by using multilength variable-weight optical orthogonal codes (MLVW-OOCs) as signature sequences and using different values of OPPM modulation parameters. Furthermore, numerical analysis is performed for two different receiver structures, namely, correlation receivers with and without hard-limiters. In our analysis, the multiple-access interference (MAI) is considered as the main performance limiting factor. In addition, the performance of the proposed system is evaluated and compared to that of traditional OOK-OCDMA system. Our results reveal that under both pulsewidth and throughput constraints, the performances of the proposed WOPPM- and UOPPM-OCDMA systems are significantly superior to that of OOK-OCDMA system.
© 2014 IEEE
Original Manuscript: February 24, 2014
Manuscript Accepted: June 16, 2014
Published: June 18, 2014
Ahmed E. Farghal, Hossam M. H. Shalaby, and Zen Kawasaki, "Performance Analysis of Multirate Multiservice Optical CDMA Networks Adopting Overlapping PPM Signaling," J. Lightwave Technol. 32, 2649-2658 (2014)