On communication protocol and beamforming design for amplify-and-forward N-way relay networks

In this paper, we consider a general wireless relay network where multiple source terminals communicate with one another with the assist of a relay node. We first propose a relaying scheme under the category of amplify-and-forward (AF) and then prove the conditions on system parameters to realize the efficient data detection from engineering perspective. From information theoretic point of view, there is no constraint on system parameters. Moreover, we obtain a general beamforming structure at the relay node, which is optimal for any objective functions, e.g., transmission rate, mean-square-error (MSE), bit-error-rate (BER), etc.