Radio channel characteristics observed for cellular and microcellular links: A tutorial review

The characteristics of the radio channel provide a challenge to the communication engineer in designing systems that are spectrally efficient so as to provide high speed services to a large numbers of subscribers. This paper reviews the characteristics of the radio channel that have been observed by various groups under conditions of interest for cellular, microcellular and related terrestrial systems. For the discussion, the characteristics are divided into those resulting from multipath scattering, such as Rayleigh fading, time delay spread and angle of arrival spread, and the amplitude variations resulting from shadowing by buildings and terrain. Ray concepts are used qualitatively to provide an explanation many of the observed characteristics and the magnitudes of various measured parameters.