On an (old) idea whose time has come: the use of smart antennas and space-time processing at the mobile

Abstract

This paper analyzes the use of smart antennas and space-time signal processing at the mobile. First, we introduce a spatio-temporal channel model from the perspective of a multiple mobile antenna receiver and configured for a bad urban propagation scenario with frequency selective Rayleigh fading, and investigate the cochannel interference conditions in a dense future cellular structure. For this environment, we then conduct a comparative study for a temporal DFE with a preselection diversity switch, and a spatio-temporal DFE that performs joint diversity, equalization, and interference suppression, all for two and three element mobile antenna arrays. Our results indicate that for the given scenario, both techniques yield gains with respect to a single antenna receiver, with the more expensive space-time method often strongly superior to the selection-based approach considered. Finally, we briefly treat a structure of processing cells that can be used for an efficient direct implementation of the spatio-temporal DFE using a QRD type of the recursive least squares algorithm.