Hybrid Beamforming Design and Implementation for Mitigating Inter-cell Interference in Flexible Duplex Cellular System

Flexible duplex is a promising technique, which provides access to flexible resource allocation and asymmetric traffic configuration. Inter-cell interference (ICI) is one of the key problems in flexible duplex cellular system. In this paper, a hybrid beamforming scheme is proposed to deal with the ICI problem. In particular, in designing the analog beamforming weights, a coordinate transformation method is introduced to transform the nonconvex optimization problem into a convex one. Moreover, an iterative algorithm is proposed to find the global optimal weights of the analog beamformer with lower computational complexity. Simulation and hardware experimental results demonstrate that significant ICI suppression can be achieved by using the proposed scheme.