On fading poisson channels with varying noise levels

In this paper, we study Poisson fading channels with varying noise levels. This model is motivated by applications of visible light communication systems, in which the noise level is affected by the strength of the background light. We consider scenarios with and without delay constraints. For the case without a delay constraint, we characterize the optimal power allocation scheme that maximizes the ergodic capacity. For the case with a strict delay constraint, we characterize the optimal power allocation scheme that minimizes the outage probability. We also provide several numerical examples to illustrate the analytical results.