Performance analysis of interleaved LDPC for optical satellite communications

Abstract

Optical wireless communications using a laser is a strong candidate for the next generation satellite communications due to its large bandwidth. However, the channel environment of satellite communications is very tough, suffering from fading by atmospheric turbulence. Therefore, an efficient channel coding such as low-density parity check (LDPC) coding is required to satisfy stable transmission. In this paper, fading noise from atmospheric turbulence is reproduced to simulate the satellite channel. Then, this time-varying signal is used to evaluate the performance of the LDPC codes in different channel environments. At the same time, in order to improve the system performance further, an interleaving method in combination with LDPC codes is proposed to overcome the problem of burst error, which frequently occurs in the optical satellite communication systems (OSC). Simulation results show that the block-interleaving scheme can achieve a 5 dB gain compared to the pure LDPC scheme. The processing time is considered to determine the proper size of interleaving blocks suitable for optical satellite communications.