A Fuse-and-Forward Protocol for Two-Way Relaying Networks With Relay Having Its Own Broadcasting Information

A fuse-and-forward (FF) relaying protocol is proposed and analyzed for two-way relaying networks where the relay node has its own information to broadcast. In our FF protocol, the relay node will firstly process the received signals to obtain a new signal version by fusing with its own information, then broadcast to all the source nodes. We assume that multiple antennas are deployed to the relay node, while only single antenna for the source nodes. To obtain full diversity and ensure the destination nodes concurrently decode the information both from the source nodes and from the relay node, a distributed space-time block code (DSTBC) is used in conjunction with unique-factorable constellation pairs (UFCPs). Especially, when the relay node is deployed with two antennas, an Alamouti-based concatenated two-way FF-STBC is presented. Upper bound analysis on the pairwise-error-probability (PEP) with maximum-likelihood (ML) decoding shows a theoretical upper bound ${{({{c_1}\ln \rho + {c_2}})}/{{\rho^2}}}$, where $\rho$ denotes the signal-to-noise ratio and $c_1$, $c_2$ are the constants independent of $\rho$.

I. Introduction

COOPERATIVE communication has been widely known as a promising research area to enhance network capacity, enlarge coverage and improve reliability [1]. According to whether the nodes are helping each other or just assisting other nodes, many cooperative or relaying communication schemes have been proposed to obtain extra performance gain in more challenging wireless communication scenarios [2], [3]. However, to the best of our knowledge, these schemes seldom consider how to achieve the expected performance when the relay also has some information to broadcast. In this letter, we firstly consider such a scenario which consists of two source nodes and one relay node. Different from those considered in [2], not only the source nodes but also the relay node in our system have information to be transmitted. It can find its application in various practical communication scenarios. One typical example is the recently-proposed local program insertion (LPI) in digital video broadcasting—next generation handheld (DVB-NGH) [4] when a local relaying tower wants to insert its own signals into those signals from the main base-station.