Performance Analysis of SAC Optical PPM-CDMA System-Based Interference Rejection Technique

Abstract

In this paper, we aim to theoretically analyse optical code division multiple access (OCDMA) system that based on successive interference cancellation (SIC) using pulse position modulation (PPM), considering the interference between the users, imperfection cancellation occurred during the cancellation process and receiver noises. Spectral amplitude coding (SAC) scheme is used to suppress the overlapping between the users and reduce the receiver noises effect. The theoretical analysis of the multiple access interference (MAI)-limited performance of this approach indicates the influence of the size of M-ary PPM on OCDMA system. The OCDMA system performance improves with increasing M-ary PPM. Therefore, it was found that the SIC/SAC-OCDMA system using PPM technique along with modified prime (MPR) codes used as signature sequence code offers significant improvement over the one without cancellation and it can support up to 103 users at the benchmarking value of bit error rate (BER) ¼ 10 -9 with prime number p ¼ 11 while the system without cancellation scheme can support only up to 52 users.

Multiplicative PIC detection for OCDMA systems with non‐negativity constraints

“…SIC and PIC detectors exhibit low computational complexity compared to the decorrelator and MMSE detectors. Several SIC and PIC detectors have been proposed in the literature [9][10][11][12][13][14]. For example in [9], an analytical comparison of optical code-division multiple-access systems with and without a SIC scheme using modified prime-sequence codes is conducted.…”

“…In [10], a SIC detector taking into consideration the shot noise, thermal noise, and phase-induced intensity noise is proposed. The same authors proposed another SIC detector using pulse position modulation (PPM) and spectral amplitude coding (SAC) [11]. In [12], the authors studied the PIC detector and developed a new approach to obtain the analytical expression of error probability in chip synchronous case, for optical orthogonal codes (OOCs).…”