  Multicasting is the general method of conveying the same information to
multiple users over a broadcast channel. In this work, the Gaussian MIMO
broadcast channel is considered, with multiple users and any number of antennas
at each node. A "closed loop" scenario is assumed, for which a practical
capacity-achieving multicast scheme is constructed. In the proposed scheme,
linear modulation is carried over time and space together, which allows to
transform the problem into that of transmission over parallel scalar
sub-channels, the gains of which are equal, except for a fraction of
sub-channels that vanishes with the number of time slots used. Over these
sub-channels, off-the-shelf fixed-rate AWGN codes can be used to approach
capacity.
