Capacity Bounds of Range-Limited Visible Light Communications Having Signal-Dependent Noise

This letter analyzes the channel capacity for range-limited visible light communications having signal-dependent noise. The input signal is constrained by the range-limited constraint and the average optical power constraint. By the variational method, we derive the capacity-infimum-achieving input distribution and a closed-form expression of capacity lower bound. Based on the dual expression of capacity and the principle of “capacity-achieving input distribution that escape to infinity”, we then derive an upper bound on capacity. We have shown that the derived capacity bounds cover most of the existing bounds. Numerical results show that the derived bounds are sufficiently tight. Moreover, the effects of different parameters on capacity performance are also discussed.