Interference Mitigation Through User Association and Receiver Field of View Optimization in a Multi-User Indoor Hybrid RF/VLC Illuminance-Constrained Network

Abstract

In this paper we address interference mitigation through user association and receiver field of view (FOV) optimization in a multi-user indoor optical wireless communication (OWC) scenario. We explore several dynamic FOV receiver solutions including steerable (SDFOV) and non-steerable (DFOV) to optimize performance for multiple devices experiencing orientation dynamics. We compare their performance to a baseline fixed FOV receiver (FFOV). Through modeling and simulation we find that SDFOV receivers outperform DFOV by up to 2.6x and FFOV by up to 5.6x in terms of average minimum throughput gain using our test scenario. Similarly, DFOV receivers can achieve up to 2.2x gain over FFOV receivers. For multi-user environments, we compare the performance of coordinated versus distributed system control. Results show that in the worst case, the distributed greedy system performs on average 46%, 16%, and 57% below the coordinated system for SDFOV, DFOV, and FFOV, respectively at a reduced computational complexity compared to the centralized system. We also note that the performance gap in each system diminishes with increasing transmitter Lambertian order. This analysis is done under different room coverage achieved through optimizing the transmitted power to jointly maximize the minimum received power and the standard illuminance range probability at the working plane. Next, we show the impact of self- and random-human blockage at different Lambertian orders on the minimum and average user throughput values. Lastly, we show the gains from employing the hybrid RF/VLC network compared to a VLC-only mode for two different strategies: (1) minimum-throughput-enhancing and (2) sum-throughput-enhancing.