SPATIAL AND TEMPORAL COMMUNICATION-THEORY USING ADAPTIVE ANTENNA-ARRAY

An adaptive antenna array or a smart antenna is named a software anten na because it can form a desired antenna pattern and adaptively contro l it if an appropriate set of antenna weights is provided and updated in software. It can be a typical tool for realizing a software radio. An adaptive antenna array can be considered an adaptive filter in spac e and time domains for radio communications, so the communication theo ry can be generalized from a conventional time domain into both space and time domains. This article introduces a spatial and temporal commu nication theory based on an adaptive antenna array, such as spatial an d temporal channel modeling, equalization, optimum detection for singl e-user and multi-user CDMA, precoding in transmitter, and joint optimi zation of both transmitter and receiver. Such spatial and temporal pro cessing promises significant improvement of performance against multip ath fading in mobile radio communications.