Performance Analysis of Mobile Receivers with Optimal Tilt Angle in Visible Light Communication System

Aiming at the difficulties that the receiver's field of view and random movement seriously affect the robustness of the visible light communication channel, this paper proposes to use the optimal-tilt-angle receiver as one of the solutions. Firstly, we take the channel capacity as the optimization goal and the Kuhn-Tucker conditions as the optimization tool to deduce the mathematical expression of the optimal tilt angle of the receiver in the single LED scene. Secondly, we propose to use the channel capacity difference between the optimal-tilt-angle receiver and the vertical-up receiver to evaluate the improvement of the channel robustness of the optimal-tilt-angle receiver. Finally, the cumulative distribution function and probability density function of the channel capacity difference are deduced when the receiver moves randomly. The simulation results show that the optimal-tilt-angle receiver improves the channel robustness more obviously in the scenes where the LED has a wide half-power semi-angle, the receiver has a narrow field of view, and the receiver has a wide range of movement.