Channel Capacity Evaluation of Optical Wireless Communication with Receiver Nonlinearity Effects

Abstract

The paper develops a theoretical model for optical wireless communication systems with receiver nonlinearity. It examines the impact of receiver nonlinearity on the maximum achievable data rate. Both lower and upper bounds on channel capacity are derived under average and peak optical power constraints. The analysis is done for single-input single-output and for multiple-input multiple-output systems. The methods apply entropy power inequalities and a dual expression approach. Numerical simulations confirm that the derived capacity bounds are tight. The results show that higher power does not always give higher capacity, since saturation and clipping at the receiver limit the channel rate. The results show that the difference between the lower and upper bounds remains small in many cases, making the bounds practical for design. These insights are useful for designing coding schemes, modulation formats and power control strategies in real optical wireless systems. The findings highlight that careful control of power is required to prevent performance loss caused by nonlinear behavior. For MIMO systems, the work explains both the potential gains and the new limits introduced by nonlinear receivers. Overall, the paper connects theoretical capacity analysis with practical hardware limitations and provides useful guidance for system designers.