Optimal Imaging Receiver Design for High-Speed Mobile Optical Wireless Communications

The optical receivers suitable for the next generation of optical wireless networks need to be ultra-high-speed while having a wide field of view (FOV) to accommodate user mobility. The design of such receivers is challenging due to two known trade-offs, namely, the area-bandwidth and the gain-FOV. In this study, we consider these trade-offs and formulate an optimisation problem to design imaging receivers that can achieve maximum high speed while satisfying a minimum FOV requirement. The design will be based on an array of arrays of photodetectors for which we present analytical derivations of signal-to-noise ratio (SNR) assuming maximum ratio combining (MRC). Practical considerations and non-idealities have been considered in our design and the reliability of the analytical model is verified by Optic Studio-based simulations. The optimization problem is solved assuming on-off keying (OOK) modulation. The results show a trade-off between achievable data rate and FOV. For example, it is demonstrated that a data rate of 23 Gbps is achievable with a receiver of at most 2 cm x 2 cm dimensions with a FOV of 15°. However, a receiver with the same dimensions may only achieve 8 Gbps if the FOV requirement increases to 20°.