Capacity Theorems for the AWGN Multi-Way Relay Channel

Abstract--The L-user additive white Gaussian noise multiway relay channel is considered, where multiple users exchange information through a single relay at a common rate. Existing coding strategies, i.e., complete-decode-forward and compressforward are shown to be bounded away from the cut-set upper bound at high signal-to-noise ratios (SNR). It is known that the gap between the compress-forward rate and the capacity upper bound is a constant at high SNR, and that between the completedecode-forward rate and the upper bound increases with SNR at high SNR. In this paper, a functional-decode-forward coding strategy is proposed. It is shown that for L 3, completedecode-forward achieves the capacity when SNR 0 dB, and functional-decode-forward achieves the capacity when SNR 0 dB. For L = 2, functional-decode-forward achieves the capacity asymptotically as SNR increases.

• Type: Journal
• Year: 2010
• Where: CORR
• Authors: Lawrence Ong, Christopher M. Kellett, Sarah J. Johnson
• Keywords: Additive White Gaussian Noise, CORR 2010, Cut-set Upper Bound, Education, Upper Bound