Sum-rate maximization in the multicell MIMO broadcast channel with interference coordination

This paper is concerned with the maximization of the weighted sum-rate (WSR) in a multicell multiple-input multiple-output (MIMO) broadcast channel (BC). Studied is the multicell network operating on the same frequency channel with multiple mobile stations (MS) per cell. With interference coordination (IC) between the multiple cells, the base-station (BS) at each cell only transmits information signals to the MSs within its cell using the dirty paper coding (DPC) technique, while coordinating the inter-cell interference (ICI) induced to other cells. The main focus of this work is to jointly optimize the encoding covariance matrices at the BSs in order to maximize the network-wide WSR. Since this optimization problem is shown to be nonconvex, obtaining its globally optimal solution is highly complex. By applying a successive convex approximation technique, this work proposes a distributed algorithm that efficiently achieves a locally optimal solution. Simulations then show that the proposed algorithm can significantly improve the network-wide sum-rate, compared to the schemes with linear precoding or no interference coordination between the BSs.