Performance Analysis of Multirate Multiservice Optical CDMA Networks Adopting Overlapping PPM Signaling

• Published in: Journal of lightwave technology Vol. 32; no. 15; pp. 2649 - 2658
• Main Authors: Farghal, Ahmed E., Shalaby, Hossam M. H., Kawasaki, Zen
• Format: Journal Article
• Language: English
• Published: New York, NY IEEE 01-08-2014; Institute of Electrical and Electronics Engineers; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Applied sciences; Exact sciences and technology; Information, signal and communications theory; Interference; Modulation, demodulation; Multiuser systems; Optical fiber communications; Optical modulation; Optical pulses; Optical receivers; Optical telecommunications; Optical transmitters; Signal and communications theory; Switching and signalling; Systems, networks and services of telecommunications; Telecommunications; Telecommunications and information theory; Transmission and modulation (techniques and equipments); code division multiple access (CDMA); Bit-error-rate (BER); multiple-access interference (MAI); quality of service (QoS); overlapping pulse-position modulation (OPPM); On-Off keying (OOK); Performance evaluation; Bit error rate; Optical telecommunication; Wireless telecommunication; Information rate; Numerical method; Pulse position modulation; Multimedia communication; Optical fiber network; Optical fiber communication; Multiple access; Pulse width; Receiver; Multirate system; Signalling; Information transmission; ON-OFF keying (OOK); Signal interference; On-off keying; Orthogonal code; Code division multiple access; Service quality; Limiter
• ISSN: 0733-8724; 1558-2213
• DOI: 10.1109/JLT.2014.2331700

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.