  We investigate and solve the rate balancing problem in the downlink for a
multiuser Multiple-Input-Multiple-Output (MIMO) system. In particular, we adopt
a transceiver structure to maximize the worst-case rate of the user while
satisfying a total transmit power constraint. Most of the existing solutions
either perform user Mean Squared Error (MSE) balancing or streamwise rate
balancing, which is suboptimal in the MIMO case. The original rate balancing
problem in the downlink is complicated due to the coupled structure of the
transmit filters. This optimization problem is here solved in an alternating
manner by exploiting weighted MSE uplink/downlink duality with proven
convergence to a local optimum. Simulation results are provided to validate the
proposed algorithm and demonstrate its performance improvement over unweighted
MSE balancing.
