Average Channel Capacity Bounds of a Dynamic Vehicle-to-Vehicle Visible Light Communication System

As vehicles trajectories are unpredictable and changing dynamically, vehicle-to-vehicle visible light communication (V2V-VLC) experiences a dynamic channel. In this work, we conduct measurements taking into account different realistic inter-vehicle distances and ambient noise levels at different times of the day in order to model and verify the dynamic V2V-VLC channel. We also derive the average channel capacity bounds by considering the impact of traffic at different times of the day, atmospheric turbulence and fog. Considering both peak and average optical power levels constraints, we derive the upper and lower bounds by using sphere packing and constraint relaxation methods, as well as truncated-exponential and truncated Gaussian distributions, respectively. The results show that the constraint relaxation method provides an improved estimation for the upper bound, whereas the truncated exponential distribution tightens the lower bound with a minimum gap of 0.4 b/s/Hz during rush hour and in a clear weather condition. We also show that the average capacity bounds of V2V-VLC are less affected by atmospheric turbulence and fog, and that the capacity during rush hours is higher by 0.7 b/s/Hz than during late hours.