Using LED Lighting for Ubiquitous Indoor Wireless Networking

Wireless networking is currently dominated by radio frequency (RF) techniques. However, the soon-to-be ubiquity of LED-based lighting motivated by significant energy savings provides an opportunistic deployment of widespread free-space optical (FSO) communications. LED-based network transceivers have a variety of competitive advantages over RF including high bandwidth density, security, energy consumption, and aesthetics. They also use a highly reusable unregulated part of the spectrum (visible light). In this paper we describe results from a pilot project to demonstrate the viability of an optical free-space visible light transceiver as a basis for indoor wireless networking. Inexpensive, commercial, off-the shelf LEDs and photodiodes were used to construct two prototypes; a simplex channel as expected as a component of an asymmetric/hybrid RF-FSO system, and a full-duplex channel demonstrating the ability to isolate multiple channels. On-off keying (OOK) was applied without observable flicker in the target modulation ranges. Results indicate the viability of creating inexpensive FSO transceivers that might be embedded in commercial lighting products to support ceiling-to-floor distances of approximately 3 m.