Phase Diversity Arrays for Mobile Communication Networks

Diversity reception is a widely used technique in radio communications to reduce signal fading due to complex propagation environments. Fading is caused by multipath propagation of the radio signal in complex environments, which in practice are either downtown areas in large cities or indoor environments. This presentation is focused on the design problem of an antenna array, which could be used for instance as a base station antenna of a radio communications system to provide antenna diversity. Special attention is given to cases, where the phase properties of the array are used to provide diversity in the same time as the radiation pattern of the array is constantly the same for all cases of the phase pattern. This special case of antenna diversity is called phase diversity. The theory in itself is rather general and it can be applied for either linear, planar or 3-dimensional array geometries. A speci c case of a planar array, which consists of two by three antenna elements, is presented as an example of a phase diversity array. The fading reduction performance of the array in a true multipath radio signal propagation environment was simulated with UTD-base raytracing radio channel model made by Nokia Telecommunications.