Multi-Cell block diagonalization precoding for multiuser MIMO broadcast channel

Multi-input multi-output (MIMO) precoding is developed for time division duplex (TDD) systems with block diagonalization (BD) relies on the channel state information (CSI) at the transmitter. Multi-cell BD algorithm is used to coordinate the transmissions across multiple evolved base stations (BSs) for downlink. In this paper, we apply BD to the downlink transmission in a cooperative multi-cell system, where the signals from different BSs to all the mobile stations (MSs) are jointly designed with the perfect knowledge of the downlink channels and transmit messages. The optimal form of BD with per-antenna power constraints and sum rate capacity are derived. Based on convex optimization techniques, this paper designs an efficient algorithm to solve this problem, and derives the structure of the corresponding optimal BD precoding matrix. The numerical results show that the proposed scheme is better performance than conventional scheme.