On the Achievable Rate-Regions for the Gaussian Two-Way Diamond Channel

Abstract: In this paper, we study rate region of a Gaussian two-way diamond channel which operates in half- duplex mode. In the channel that we consider in this paper, Two Transceiver (TR) nodes exchange their messages with the cooperation of two relay nodes. We consider a special case of the Gaussian two-way diamond channels which is called Compute-and-Forward Multiple Access Channel (CF-MAC). In the CF-MAC, the TR nodes transmit their messages to the relay nodes which are followed by a simultaneous communication from the relay nodes to the TRs. Adopting rate splitting method in the terminal encoders and then using Compute-and-Forward (CF) relaying and decoding the sum of messages at the relay nodes, an achievable rate region for this channel is obtained. To this end, we use a superposition coding based on lattice codes. Using numerical results, we show that our proposed scheme outperforms the other similar methods and achieves a tighter gap to the outer bound.