Reduced Computational Complexity Beamspace Beamforming Design for MIMO Multicast Systems

An algorithm with reduced computational complexity for solving the transmit beamforming problem in the case of multiple co-channel multicast groups is considered. A new degree of freedom, which allows a trade-off between the transmission power, the number of antenna array elements and the computational time, is added. The optimization problem is transformed to a lower-dimensional optimization problem, which allows an antenna array with higher number of elements to operate with significant decrease in transmission power, while the increase in computational time is minor. The trade-off between the delay and the transmit power appears to be a promising direction for a cross-layer optimization research.