Low cost pre-coder design for MIMO AF two-way relay channel

In this letter, we revisit the pre-coder design problem for the amplify-and-forward two-way relay channel with multiple antennas equipped at each node. Based on generalized singular value decomposition (GSVD), we propose a novel pre-coding technique named Hermitian Relay Pre-coding (HRP) with a relatively low design complexity. Compared with the existing GSVD pre-coding method, HRP can achieve a higher rate by avoiding zero-forcing operation but keeping the same design complexity.