Downlink beamforming and SINR balancing for the simultaneous provision of unicast/multicast services

The provision of multicast services is a relevant feature within the context of the further evolution of cellular communication systems. The scope of this paper lies on the application of adaptive antenna arrays in order to allow for space division multiple access (SDMA) in a scenario with both unicast and multicast users. A sub-optimum algorithmic solution is proposed for the problem of maximizing the minimum SINR perceived by the unicast/multicast users (SINR balancing), while satisfying the transmit power constraint. It is based on the unicast-only solution, which has been extended to the unicast/multicast case. It is shown that the proposed low-complexity algorithm provides a reasonable approximation to the optimal solution, outperforming diagonalization-based procedures such as block diagonalization.