Beamforming vector design for regenerative wired two‐way relay systems

A new structure for a regenerative two‐way relay (TWR) system, called a wired TWR (WTWR) system is introduced. The WTWR consists of two relay nodes that are connected through an optical link, and it operates as a single conventional TWR node. For the WTWR system, beamforming vectors maximising the sum rate of two source/destination nodes (i.e. users) are designed. The WTWR exploiting the proposed beamforming is applicable to various systems that can employ a TWR protocol, such as heterogeneous networks, distributed antenna systems, and coordinated multipoint transmission systems.