Physical properties of wireless infra-red systems and comparison with MMW radio systems

Two alternatives for indoor wireless communications are considered, using infra-red (IR) and the millimetre-wave (MMW) band. Three possible system configurations, point-to-point, diffuse and quasi-diffuse are described. Technological and safety constraints are examined for IR as well as transmission capacity, terminal mobility and noise power levels. Finally a comparison between the characteristics of possible system configurations that could be realised in the frequency regimes is presented.