A Lattice-Based Compress-and-Forward Strategy for Gaussian Two-Way Relay Channel With Direct Links

In this letter, the Gaussian two-way relay channel with direct links is investigated in which two users aim at exchanging their messages with the help of a relay node. We propose a new lattice-based compress-and-forward strategy and obtain its achievable rate-region. We show that the proposed scheme is superior to all previously known achievable schemes for channel gains larger than one. In particular, under the symmetric case, the proposed scheme is able to achieve a capacity region within 0.5 bit or (1/2) log3 ≅ 0.79 bit, depending on the power of the relay.