Indoor radio channel models for manufacturing environments

Mathematical models which estimate the number and amplitude of multipath signals in a typical factory environment, and the probability that a multipath component is likely to occur for a given excess delay interval are presented. A technique for determining receiver threshold for channel impulse response measurements is analyzed and applied to show that the interpretation of measured results is critically dependent on the value of receiver threshold used. Models for the number of paths, the likelihood of multipath components, and the strength of the multipath components are given as functions of topography and transmitter-receiver separation. It was shown that a Rayleigh distribution for the amplitude of multipath components is a very good model. The likelihood of multipath was shown to fall off exponentially with excess delay at high threshold values and linearly at lower threshold values. Using a pulse resolution of 7.8 ns, the number of multipath components are shown to fit either a Poisson distribution or a uniform distribution, depending on the received power threshold of the receiver.