Performance evaluation of 2 × 2 MIMO-OFDM-based radio-over-fibre system using Alamouti coding and Hammerstein equaliser

Abstract

Radio-over-fibre (RoF) systems consist of two subsystems including optical subsystem and wireless radio frequency subsystem. It is shown that by using multiple-input multiple-output (MIMO) and orthogonal frequency-division multiplexing (OFDM) systems, the RoF transmission can be improved in frequency-selective channels. In this study, two different configurations of MIMO–OFDM-based RoF systems are compared for the long-term evolution standard under different non-linearity levels, bandwidths, and fading channel conditions. Using the total degradations (TD) criterion, an appropriate quiescent point is determined to decrease the impact of non-linearity level, and hence the performances of different MIMO detection methods are compared. Bit error rate results demonstrate that by using Hammerstein type equaliser, the system performance is improved under different conditions including different fading channels, Doppler frequencies, bandwidths, and output back off levels. Results demonstrate that with an appropriate structure for MIMO–OFDM–RoF systems, a suitable quiescent point can be found for all scenarios by employing Alamouti coding and Hammerstein equaliser.