  In this paper, we propose an adaptive coordinated Tx-Rx beamforming scheme
for inter-user interference cancellation, when a base station (BS) communicates
with multiple users that each has multiple receive antennas. The conventional
coordinated Tx-Rx beamforming scheme transmits a fixed number of data streams
for each user regardless of the instantaneous channel states, that is, all the
users, no matter they are with ill-conditioned or well-conditioned channels,
have the same number of data streams. However, in the proposed adaptive
coordinated Tx-Rx beamforming scheme, we adaptively select the number of
streams per user to solve the inefficient problem of the conventional
coordinated Tx-Rx beamforming scheme. As a result, the BER performance is
improved. Simulation results show that the proposed algorithm outperforms the
conventional co-ordinated Tx-Rx beamforming algorithm by 2.5dB at a target BER
of 10^-2
