AbstractIn order to respond to the increasing demand of capacity and bandwidth caused by the high number of wireless applications and users, LiFi technology was introduced. It uses the visible light spectrum instead of the radio spectrum to transmit data wirelessly through the illumination of LED lamps. The main advantage of this technology is to provide wireless communications with high data rates. Other advantages include efficiency, availability, security and safety. Also, this technology uses free unlicensed spectrum, and it is cost-effective. Additionally, unlike RF systems, no multipath fading and the transmitter and receiver circuits are not complex. However, LiFi has several issues, which include high path loss, sensitivity to blockages and Non-line-of-sight (NLOS) situations. Probably, the biggest issue of LiFi is the uplink communication which is difficult to implement due to practical and cost reasons. Several future applications of this technology include places where RF is restricted such as hospitals and airplanes. Also, it can be used for traffic management, underwater communication, and outdoor access to the Internet. Moreover, it can be combined with WiFi technology either in hybrid technique or aggregated technique. It is found that later technique gives better results. Another possible application is the optical attocells. It is found that the hexagonal cells model is the best for deterministic deployments of optical APs, whereas the hard-core point process (HCPP) model is the best for random deployments. Furthermore, LiFi can be used for multiuser access with high data rate by using non-orthogonal multiple access (NOMA) technique. Due to the great features of LiFi, more applications and everyday life devices will adopt this technology in the future. However, Because of its limitations, it may not totally replace RF technology, but they will work collaboratively to achieve a better performance.
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