  This work focuses on the downlink communication of a multiuser MIMO system
where the base station antennas and the users' receiving antennas are all
active, but at each transmission, only a subset of the receive antennas is
selected by the base station to receive the information symbols, and the
particular chosen subset (pattern) represents part of the information conveyed
to the user. In this paper we present a mathematical model for the system and
develop expressions that are fairly general and adequate for its analysis.
Based on these expressions we propose a procedure to optimize the choice by the
ERB of the sets of antenna patterns to be used in the transmissions to the
different users, aiming at the maximization of the detection signal-to-noise
ratio. Performance results, with and without the optimization procedure, are
presented for different scenarios.
