  In this paper, we consider linear precoding with SINR constraints for the
downlink of a multiuser MISO (multiple-input single-output) communication
system in the presence of imperfect channel state information (CSI). The base
station is equipped with multiple transmit antennas and each user terminal is
equipped with a single receive antenna. We propose a robust design of linear
precoder which transmits minimum power to provide the required SINR at the user
terminals when the true channel state lies in a region of a given size around
the channel state available at the transmitter. We show that this design
problem can be formulated as a Second Order Cone Program (SOCP) which can be
solved efficiently. We compare the performance of the proposed design with some
of the robust designs reported in the literature. Simulation results show that
the proposed robust design provides better performance with reduced complexity.
