A description of the physical mechanism causing multipath propagation in built-up areas is followed by a discussion of the various ways in which fading radio communiction channels can be described. It is shown that characterisation in the time-delay/Doppler-shift domain explicitly illustrates the multipath nature of the channel and provides parameters relevant to system design. A brief discussion of channelsounding techniques is followed by a description of a wideband channel sounder using matched-filter signal processing in the receiver.