An enhanced random beamforming scheme for signal broadcasting in multi-antenna systems

In this paper, a signal broadcasting scheme based on random beamforming is proposed to achieve omnidirectional coverage for public channels in multi-antenna cellular systems. Determining the basic weight vector achieving a pattern amplitude as flat as possible in the angular domain and forming a pair of complementary patterns on each time-frequency resource block, the resulting transmit power become isotropic instantaneously in the whole cell. As a result, it is verified by theoretical analysis and numerical results that the proposed scheme achieves the upper-bound performance in correlated antenna arrays, and is robust to failures and calibration errors of radio frequency chains. Moreover, the proposed scheme is a low-cost and power-efficient solution by making full use of the power amplifiers.