Using wideband directional channel models for spatial filtering in mobile communications

Separate but related studies have consistently shown how directional and wideband characteristics of the mobile propagation channel fundamentally establish physical constraints behind the spatial separation of signals. Their overall perspectives are hereby presented, extracting general guidelines to support the application of wideband directional propagation channel models. These aim at correctly and practically evaluating the performance of spatial filtering techniques. It is not the nature or the specificities of a model that are at stake, but how it should be applied. For the purpose of evaluating spatial processing techniques on a known channel model basis, it is argued that it should allow for statistical relevance, also involving sufficiently low implementation complexity; it should be characterised by physical quantitative measures of the channel richness; it should cover both macro-and microcell environments, for the same model nature, and possibly picocells; it ought to be applicable in the form of multiuser propagation scenarios, approximating a wide variety of practical interference situations; lastly, by being double-directional, its inherent nature should allow for its flexible and complete application to all types of single- or multiple-input, single- or multiple-output frameworks.