Enhanced Performances of W/S SAC-OCDMA System Using LDPC Code

Abstract

In an incoherent optical code division multiple access (OCDMA) system using amplitude spectral coding (SAC), which exceeds 1.5 Gbps, it is difficult or impossible to make a transmission with a bit error rate better than 10–9. For this, it is necessary to associate an error correction code (ECC) to the SAC-OCDMA system. In this paper, we proposed an architecture of a two-dimensional SAC-OCDMA system (spectral (w) and spatial (s)) using multi-diagonal code (MD) as spreading code and low-density parity check code (LDPC) as ECC. According to the properties of the MD code and the proposed architecture, the phase induced intensity noise is eliminated, which has improved the performance of the system. The theoretically results shows that LDPC/2D-SAC-OCDMA allowing more than 40 users to be multiplexed compared to a non-coded 2D SAC-OCDMA system. This combination allowed us to increase the cardinality of the LDPC/SAC-OCDMA (W/S) system without using an optical hard limiter.

Performance enhancement of visible light communication (VLC) system incorporating WMZCC‐OCDMA codes and PDM‐QPSK‐DSP data encoding

“…Light emitting diodes (LEDs) were used in ZCC‐SAC codes, but their noncoherence, broad spectrum and directionless nature limited transmission distance; thus, SAC codes were recently implemented with lasers and successfully extended the reach of optical transmission 31–33 . A 20 Kb/s data speed using Ethernet OCDMA and LEDs in multi‐user VLC over 100 cm with a synchronism mechanism was reported in 2012.…”