Pareto Boundary for Massive-MIMO-Relay-Assisted Interference Networks: Half-duplex vs. Full-duplex Processing

Abstract:
Due to the absence or insufficient strength of the direct links between communication pairs, relay-assisted communication is inevitable in communication networks. One important class of such networks is the interference relay channel, whose Pareto boundary of the achievable rate region is investigated in this paper. The relay is equipped with multiple antennas for transmission and reception while the source and destination nodes have a single antenna each. Due to relatively high strength of the relay links compared to the direct links, the destinations decode the relay signals while the other receiving signals from the sources through direct links are treated as noise (TIN). We consider both zero-forcing (ZF) and maximum ratio transmission/ combining (MRT/MRC) at the relay input and output, while the relay can either operate in half-duplex or full-duplex mode. The power is optimized in order to characterize the Pareto boundary considering these two types of beamforming strategies. We formulate the weighed max-min optimization problem which delivers the Pareto boundary. This problem turns out to be a geometric program (GP) which can be converted to a convex optimization problem and solved efficiently. We observe that, by increasing the number of transmit and receive antennas at the relay significantly, full-duplex outperforms half-duplex even at strong self-interference channels.