  In this paper we aim to solve the multiuser multi-input multi-output (MIMO)
downlink beamforming problem where one multi-antenna base station broadcasts
data to many users. Each user is assigned multiple data streams and has
multiple antennas at its receiver. Efficient solutions to the joint
transmit-receive beamforming and power allocation problem based on iterative
methods are proposed. We adopt the group maximum
signal-to-interference-plus-noise-ratio (SINR) filter bank (GSINR-FB) as our
beamformer which exploits receiver diversity through cooperation between the
data streams of a user. The data streams for each user are subject to an
average SINR constraint, which has many important applications in wireless
communication systems and serves as a good metric to measure the quality of
service (QoS). The GSINR-FB also optimizes the average SINR of its output.
Based on the GSINR-FB beamformer, we find an SINR balancing structure for
optimal power allocation which simplifies the complicated power allocation
problem to a linear one. Simulation results verify the superiority of the
proposed algorithms over previous works with approximately the same complexity.
