Secure communications: The infrared alternative

Abstract

Much of the world's high-speed communications travel through optical fibres, and a rapidly-increasing demand for network bandwidth to accommodate both data and voice traffic has developed. There is a bottleneck in the access network to enable delivery of multimedia services to residential and small business customers. Coupled with this is a rapidly-growing demand for mobility via wireless technologies, driven by expansion in the use of PDAs and mobile telephones. The ubiquitous nature of computer terminals in the modern office also means that a wireless network, devoid of the inconvenience and cost of reconfiguring wired systems, is increasingly appealing (communications "anytime, anywhere"). The use of infrared communications through free space, or optical wireless, is very promising, as a means of supporting the high bit rates which will be required by future multimedia services, since it offers potentially large unregulated bandwidths. Recently there has been increased recognition of the advantages of the optical portion of the spectrum when compared to radio as a medium for short-range communication. This, coupled with technological advances such as the Warwick optical antenna, has produced a growth in interest in optical wireless systems for both in indoor and outdoor applications. In particular, optical wireless offers high bandwidth at low-cost, immunity to radio interference, an unregulated spectrum and small components that consume little power. This paper briefly reviews optical wireless, and shows how it is developing and permitting unprecedented free spectrum, secure, immune from the effects of any other RF communications, and internationally and freely available.