Design and Implementation of an End-to-End Amplify and Forward Full-Duplex Relay Network

This paper presents the design and implementation of an In-Band Full-Duplex (IBFD) amplify and forward relay for wireless networks. First, we describe the system model of the full-duplex relay (FDR), where the relay extends the range of the source node to reach a destination node located outside the source's radio coverage. We analyze the gain limitation of FDR under the stability and transmit power constraints. Further, the operation of tandem FDRs, and their limitation factors are discussed. We analyze the overall system performance as a function of relay location for constant gain and constant transmit power operating modes. The optimal FDR gain maximizing end-to-end network performance is computed. The full-duplex (FD) and half-duplex (HD) system performances are evaluated by simulation and experiments for both outdoor and indoor environments. Experimental results show up to 23dB signal to noise plus interference ratio (SINR) improvement in constant gain mode and up to 14dB SINR improvement in constant transmit power mode. The measured network throughput of FD network shows up to 1.8 times improvement compared to the HD counterpart. Finally, the optimal relay location is selected to maximize SINR at the destination.