A Half-Duplex Two-Way Relay Station Assisted Cellular Uplink and Downlink Communications

Abstract:
In this paper, we study a cellular system where both Uplink (UL) and Downlink (DL) communications are simultaneously assisted by a common intermediate half-duplex (HD) two-way relay station (RS). We aim to show if two-way relaying mechanism would provide any advantages over time-division duplex (TDD) cellular communication systems in terms of power saving at mobile terminals, coverage extension, quality of service (QoS) and capacity improvement. For this particular scenario, we stick to a simple two-phase two-way relaying protocol in order to better understand the potentials of two-way relaying in the cellular communication context. Pertinent to this two-phase two-way relaying protocol, achievable rates for Amplify-and-Forward (AF), Decode-and-Forward (DF) and Compress-and-Forward (CF) relaying strategies are derived. Achievable rate analysis shows that using a HD two-way RS in the cellular communication systems does not introduce any duplexing loss. Numerical results also reveal that exploiting two-way relaying mechanism in cellular systems, would provide better achievable rate and coverage extension performance than the conventional cellular system case.