Non-Coherent and Semi-Coherent Denoise-and-Forward Schemes for Two-Way Relaying
Zoran Utkovski, Petar Popovski · Goce Delchev University Repository (Goce Delčev University of Štip) · 2012
It is known that bi-directional (two-way) communication between the terminals in a network with relays assisting the communication increases the spectral efficiency of the network. However, with the benefit of higher throughput comes the burden of more overhead as well as an increased effort in channel estimation. Most schemes for relaying require prior knowledge on the channel at the terminals and at the relays. In contrary to these schemes, we look at scenarios where either no channel knowledge, or only partial (realistic) channel knowledge is assumed. We denote these scenarios as non-coherent and semi-coherent, respectively. We combine the paradigm of subspace-based communication originally developed for non-coherent point-to-point channels, with two-way relaying schemes based on denoise-and-forward (DNF). DNF is a form of wireless physical layer network coding scheme where the relay does not jointly decode the signals from the terminals, but it maps the received signals into symbols from a discrete constellation and broadcasts. The aim of this work is to demonstrate that denoising can be performed without any, or at least only with partial channel knowledge.