BER analysis of relay assisted PSK with OFDM ROFSO system over Malaga distribution including pointing errors under various weather conditions

Abstract

Radio on free-space optics (ROFSO) remains cynosure for researchers, since it supports huge bandwidth and high data rate transfer then compared to Radio frequency (RF) networks. Thus substituting RF with ROFSO. Since signal transmitted in free space is influenced by the atmospheric changes which results in signal deterioration once it reaches receiver. The deterioration would depend upon the distance between transmitter and, as distance increases signal attenuation would be more and system would be irrelevant. In this work we investigate bit error rate (BER) performance of ROFSO system using orthogonal frequency division multiplexing(OFDM) scheme with phase shift keying (PSK) modulation using decode and forward relay (DF) nodes. We derive closed form mathematical expressions for the estimation of average BER of DF based multi-hop serial based ROFSO communication system with the combined effects of path loss, pointing errors (i.e., misalignment fading), and atmospheric turbulence-induced fading modelled by M distribution have been investigated in detail. And we infer that with relays incorporated as we increase hops (L) total link length of the ROFSO system is enhanced significantly.