On the Achievable Rates of Symmetric Gaussian Multi-Way Relay Channels
Considering a symmetric Gaussian Multi-Way Relay Channel (MWRC) with K users, this paper compares two transmission strategies, namely One-Way Relaying (OWR) and Multi-Way Relaying (MWR), in terms of their achievable rates. While in OWR, only one user acts as data source at each time and transmits in the uplink channel access, users can make simultaneous transmissions in MWR. First, the authors prove that for MWR, lattice-based relaying ensures a gap less than 1/2(k-1) bit from the capacity upper bound while MWR based on Decode-and-Forward (DF) or Amplify-and-Forward (AF) is unable to guarantees this rate gap. For DF and AF, they identify situations where they also have a rate gap less than 1/2(k-1)bit.