  Consider a simple two-way relaying channel where two single-antenna sources
exchange information via a multiple-antenna relay. To such a scenario, all the
existing works which can achieve full diversity order are based on the
antenna/relay selection, where the difficulty to design the beamforming lies in
the fact that a single beamformer needs to serve two destinations. In this
paper, we propose a new full-diversity beamforming scheme which ensures that
the relay signals are coherently combined at both destinations. Both analytical
and numerical results are provided to demonstrate that this proposed scheme can
outperform the existing one based on the antenna selection.
