Resource allocation and BER performance analysis in OFDMA VLC systems

Wireless body area networks (WBANs) can be utilized for remote observation of patients and old individuals at home as medical applications. Visible light communication (VLC) has been proposed as an efficient technology for medical WBANs. By considering the key feature of VLC systems, VLC can be used in extra-WBAN links from node (patients) to access point. Since symbol error rates (SERs) is critical metric in medical WBANs, we propose joint power and subcarrier allocation scheme in VLC systems to minimize SERs subject to transmit power limitation, and required minimum rate for each user. Here, the improved channel model is utilized for VLC link between different numbers of patients and access point which is considered received signal power dependence noise (RSN). In addition, the effect of tilting assisted receiver on resource allocation is evaluated. Moreover, to address real-world challenges like patient movement and obstructions, we propose incorporating wall-mounted mirrors to reflect light signals and thus maintain reliable communication, considering both line-of-sight (LoS) and non-line-of-sight (NLoS) transmission. The numerical results indicate that RSN and receiver tilting have a significant impact on the allocation of resources. Furthermore, it is shown that outage probability can approach zero using the NLoS link of proposed wall-mounted mirrors.