Abstract: To improve the multiplexing gain and reduce the hardware cost of antennas in massive multiple-input multiple-output systems, a hybrid precoding algorithm based on the fully-connected antenna structure was proposed. Aiming at minimizing the multiuser weighted minimum mean square error, an optimization problem was established under the constraints of antenna structure, user fairness and the limitation of power and the hybrid precoding problem was solved by utilizing the best approaching to the digital precoding. Simulations verify that the proposed algorithm narrows down the gap between the hybrid precoder and the optimal one-stage precoder to the greatest extent with a good convergence and obtains a near-optimal solution with significant gain.

Key words: massive multiple-input multiple-output, fully-connected antenna structure, hybrid precoding, weighted minimum mean square error