Adaptive beamforming selection methods for inter-cell interference cancellation in multicell multiuser systems

In this paper, we study an inter-cell interference cancellation (ICIC) scheme for multicell multiple-input single-output downlink systems where each base station (BS) simultaneously supports multiple active users and only partial channel state information (CSI) is shared among BSs. Each BS jointly selects one of following beamforming strategies: an egoistic zero-forcing beamforming (ZFBF) which applies the ZFBF for only home users and an altruistic strategy which performs the ZFBF for both home users and neighboring users for ICIC. We first derive closed-form expressions for the average rate of an individual user in 2-cell and 3-cell networks when BSs choose one of the aforementioned beamforming strategies. With the derived closed-form expressions, we propose a multiuser adaptive ICIC scheme in order to maximize the average sum rate of the system based on user locations. Numerical results show that the proposed scheme outperforms conventional methods in terms of the average sum rate for both 2-cell and 3-cell networks.