Real-time optimal tracking angles of photodiodes for MC-VLC in indoor mobile scenarios

Next significant revolution of virtual/augmented reality and Internet of things show the remarkable demands of next-generation indoor mobile real-time data transmission are high spectral-efficiency, high-speed and high-density deep coverage. Multi-color visible light communication (MC-VLC) has remarkable potential to confront the challenges due to the large equivalent bandwidth index and extensively installed of multi-color light emitting diodes. However, although optical filters are utilized, there are wide spectrum interference (WSI) in MC-VLC system. Meanwhile, the alignment and availability of photodiodes (PDs) greatly influence the WSI and target signal (TS). So the real-time optimal tracking angles (ROTAs) of PDs is proposed to obtain the optimal alignment minimizing the total interference signal ratio to achieve trade-off of WSI and TS. The optimal problem is formulated and the alternative tracking angles sets are obtained to prepare for the analytic solution of ROTAs. The ROTAs has extremely low complexity, and the result of that converges on the numerical solution of exhaustive search. Better BER performance can be achieved by system with ROTAs than with fixed tracking angles at different relative offset angle between the transmitter and the receiver.