On the Performance of SPAD-Based Optical Wireless Communication with ACO-OFDM

The nonlinear distortion introduced by the dead time strongly limits the throughput of the highly sensitive SPAD-based optical wireless communication (OWC) systems. Optical OFDM can be employed in the systems with SPAD arrays to improve the spectral efficiency. In this work, a theoretical performance analysis of SPAD-based OWC system with asymmetrically-clipped optical OFDM (ACO-OFDM) is presented. The impact of the SPAD nonlinearity on the system performance is investigated. In addition, the comparison of the considered scheme with DCO-OFDM is presented showing the distinct reliable operation regimes of the two schemes. In low optical power regimes, ACO-OFDM outperforms DCO-OFDM with around 4 dB power gain achieved by 16-QAM ACO-OFDM over 4-QAM DCO-OFDM. However, DCO-OFDM is in turn more preferable in high power regimes which extends the maximal tolerable received optical power by 7.4 dB.