One- and Two-Way Decode-and-Forward Relaying for Wireless Multiuser MIMO Networks

In this paper, the authors propose multiuser Multiple-Input Multiple-Output (MIMO) one- and two-way relaying protocols. Several wireless MIMO node pairs are establishing either unidirectional or bidirectional transmission links via a single decode-and-forward MIMO relay without causing interference to each other. For both half-duplex two-phase relaying protocols, the relay separates messages of different node pairs spatially by using zero-forcing based methods, whereas, in order to cancel the interference within the bidirectional links, XOR precoding followed by self-interference cancellation is employed. Both sum rate and maxmin fairness optimizations, as well as quality-of-service assurance, are considered for the design of the precoders at the relay.