Rotating Decode-and-Forward for Two Pairs of Two-Way Communications

We study the transmission strategy for a system consisting of two pairs of two-way communication links. The information exchange between the two nodes in each pair can only occur with the help of the nodes in the other pair. A novel transmission protocol, named Rotating Decode-and-Forward (RDF) is proposed. In this protocol, the two pairs take turns to forward the signal for each other while having their own information embedded in the signal-to-forward by applying physical layer network coding. The achievable rate region of this protocol is derived. Numerical examples show that proposed RDF protocol can provide significantly higher spectral efficiency than conventional protocols where the transmissions of information signal and signal-to-forward are carried out separately.