WiFO: A hybrid communication network based on integrated free-space optical and WiFi femtocells

Abstract

Developments in smart home technology and the Internet of Things have significantly increased the demand for high-speed indoor wireless links. Although the majority of the research conducted in this area is still focused on the efficient usage of radio frequency (RF) spectrum, free-space optical (FSO) networks have also been explored as an alternative due to their large bandwidth potentials and low interference. In this paper we present a hybrid FSO and WiFi system (WiFO) that seamlessly integrates optical femtocell architecture with high mobility WiFi networks. Each FSO femtocell in this indoor communication system is capable of transmitting and receiving data at a rate of 50 Mbps over a distance of up to three meters with a field-of-view of ±15° while still achieving a low bit error rate between 10−6, and 10−4. Reed–Solomon forward error correction codes were also applied to the data stream to further reduce the bit error rate to below 10−7. Different than many other free-space optical communication network using static transceivers, mobility in our WiFO system is achieved through the integration of a WiFi channel in the network protocol. The WiFi channel provides a feedback mechanism and allows for seamless handoffs between FSO femtocells. Additionally, we have experimentally demonstrated the advantage of this WiFO architecture by comparing the throughput of our system with a standard WiFi link in a realistic scenario. Our investigation has shown that the WiFO system presented in this work offers a cost-effective and easy-to-implement approach to significantly increase the capacity of current WiFi networks.