Novel family of prime codes for synchronous optical CDMA

Abstract

In this paper we have proposed a novel prime spreading sequence family hereby referred to as "new-Modified Prime Code (n-MPC)" for direct-detection synchronous optical code-division multiple-access (OCDMA) networks. The new code has been applied to Overlapping Pulse-Position Modulation (OPPM) CDMA system and the performance of system is evaluated. In addition, we have analyzed the system throughput and also introduced a new interference cancellation technique which significantly improves the bit error probability (BEP) of OPPM-OCDMA systems.

Multiple access interference cancellation in Manchester-coded synchronous optical PPM-CDMA network

“…As compared to the other prime code family with same code-length (Liu et al 2007) and others such as perfect difference codes (PDC) (Wu et al 2004), it uses unipolar (i.e., power saving) and also it provides an almost orthogonal correlation property in an appropriate codelength. According to the PMPC sequences (Liu and Tsao 2000), for prime number P the number of sequences (users) in the entire code family is P 2 with code-length of P 2 + P .…”

“…attentions (Kwong et al 1991;Liu and Tsao 2000;Wakafuji and Ohtsuki 2003;Shalaby 1999;Lee et al 2001;Liu et al 2007;Wu et al 2004;Shalaby 1998;Karbassian and GhafouriShiraz 2007) due to appreciating the low propagation loss and the huge available bandwidth offered by specially single-mode optical fibers. Synchronous OCDMA (S-OCDMA) has some advantages over asynchronous OCDMA (A-OCDMA) ones (Kwong et al (1991)).…”

“…Pulse-position modulation (PPM) (Lee et al 2001;Liu et al 2007;Wu et al 2004;Shalaby 1998;Karbassian and Ghafouri-Shiraz 2007) as an energy efficient modulation excels OOK if the average power rather than chip-time is the limiting factor and also securer than OOK regarding detection. In practical OCDMA though the chip-time is important but power issues come to critical point in individual optical network units (ONU) as well.…”

Performance Analysis of Novel Prime Code Family in Coherent Optical CDMA Network

“…It is now clear where the expression 'Double-Padded' comes from. Finally, these two sequences are padded into each modified prime codes and consequently the code enlarges by 2P as compared with MPC and by P as compared to both padded-modified prime code [8] and new-modified prime code [9]. This implies an increase in the chip-rate (processing factor in spreading) which makes the proposed new code more secure (i.e.…”

Uniform Cross-Correlation Modified Prime Code for Applications in Synchronous Optical CDMA Communication Systems

“…These include original prime code (PC), extended prime code, modified prime code (MPC) [4], [6], padded MPC (PMPC) [12], the new MPC (n-MPC) [7], double-padded MPC (DPMPC) [13], modified prime codes [14], generalized prime code, carrier-hopping and multi-carrier prime codes [4]. Furthermore, performance analysis of most of these code families has been investigated in On-Off Keying (OOK) and Pulse Position Modulation (PPM).…”