Orthogonal frequency division multiple access (OFDMA)-Based visible light communication systems

Abstract

Visible Light Communication (VLC) exploits visible light for high-speed data transmission; it serves as the medium for transmission using intensity modulation. Orthogonal Frequency Division Multiple Access (OFDMA) grants concurrent resource access to users at the physical layer. One of the challenges faced in this access grant is the flickering effect of the perceptible lights. The intensity degradation reduces the access grant as the transmission medium is less utilized. An Access-centric Modulation and Decoding Technique (AMDT) is introduced for VLC systems to address this issue. The proposed technique identifies two influencing factors: the degrading rate and decoding interval. The first factor identifies the feeble access links due to flickering, and the second determines the variation for allocating access links based on degradation. The first factor is estimated using federated learning across the available access links. This learning calculates the degrading factor per interval after the available access links. The learning provides insight into the maximum and minimum variation that reduces or maximizes the decoding interval. Based on the available user access and degraded access links, further allocations are provided using high decoding rates. This process is amendable based on user density and light intensity regardless of the flickering rate.