Resilient Optical Wireless Communication Through WDM-Based RIS-Assisted Multi-Connectivity

The susceptibility of a Line-of-Sight (LOS) link in Optical Wireless Communication (OWC) to blockage is a major challenge affecting its deployment for next generation networks. Another challenge is the random orientation of the receiving device which also affects the amount of received optical power when the incidence angle is high. Reflecting Intelligent Surfaces (RIS) is a promising technology for using non-LOS (NLOS) communication. This work aims to study the effect of these LOS link impairments on Wavelength Division Multiplexing (WDM)-based resource allocation in OWC with and without the use of RIS elements and the effect on resilience. In this work, we adopt the state-of-the-art Orientation-based Random Way-Point (ORWP) model for mobility and random orientation of the User Equipment (UE) and calculate blockage geometrically assuming human objects since OWC links are not independent in contrast to RF-based communication. We propose multi-connectivity with physical path disjointness using multiple Angle Diversity Receiver (ADR) designs to evaluate the system performance using both a Mixed Integer Linear Program (MILP) and a low-complexity algorithm.