A-STBC incorporated power-efficient Radio over Fibre system

Abstract

MIMO–OFDM based Radio over Fibre (RoF) system has emerged as a potential candidate to realize highly-reliable, power- and spectral-efficient wireless systems. However, low spectral-efficiency in conjunction with high peak-to-average power ratio (PAPR) of the FFT based conventional OFDM degrades the system performance and demands high power to attain the required BER. To reduce this high power requirement to attain the threshold BER (10−3), a discrete wavelet transform (DWT) approach is incorporated with conventional MIMO–OFDM-RoF system in this work. The proposed Wavelet-OFDM (W-OFDM) system is integrated with Alamouti-Space–time Block Codes (A-STBC) and the resulting MIMO–OFDM signal is transported over a RoF link of 10 Km in the presence of non-linearity. Moreover, at radio access point (RAP), the received RF signals are transmitted over Rayleigh faded wireless-channel in the presence of additive white Gaussian noise (AWGN) and phase-offset arising due to imperfect carrier phase-estimation. The proposed system equipped with 16-PSK and 64-PSK modulation schemes claims power efficacy of 68% and 40% respectively in achieving the threshold BER in contrast to the conventional system under low non-linearity scenario.