Efficient Coordinated Multicell Beamforming with Per-Base-Station Power Constraints

This paper is concerned with optimal downlink beamforming designs in a coordinated multicell system with per-base-station power constraints. At each cell, a multiple-antenna base-station (BS) employs linear beamforming to send multiple data streams to its remote mobile-stations (MS). With the coordination between the cells, the multiple BSs jointly optimize their beamformers to enhance the overall system performance. Under per-BS power constraints, considered are the two following design criteria: (i) minimizing transmit power with guaranteed signal-to-interference-plus-noise ratio (SINR) at each each MS and (ii) jointly maximizing the minimum SINR margin at the MS. The two optimization problems are reformulated as second-order conic programs (SOCP), and simple and fast converging numerical algorithms to efficiently solve them are proposed.