Performance Comparison Between Coherent and DCO-OFDM LiFi Systems

This paper compares an intensity modulation/direct detection (IM/DD) light fidelity (LiFi) system using direct current biased optical orthogonal frequency-division multiplexing (DCO-OFDM) and a coherent LiFi system using homodyne detection. The performance metrics of bit error ratio (BER) and the power efficiency are compared between the two systems. In addition, the channel direct current (DC) gain characteristics of the two systems are investigated. Simulation results show that the coherent system achieves a better BER performance than the IM/DD system, but the transmitter and the receiver of the coherent system need to be perfectly matched. Also, within the same coverage area, the coherent system is more power efficient than the IM/DD system.