Capacity Region of the Two-Way Multi-antenna Relay Channel with Analog Tx-Rx Beamforming

  • Cristian Lameiro
  • Alfredo Nazábal
  • Fouad Gholam
  • Javier Vía
  • Ignacio Santamaría
Part of the Lecture Notes of the Institute for Computer Sciences, Social Informatics and Telecommunications Engineering book series (LNICST, volume 81)


In this paper we study the multiple-input multiple-output two-way relay channel (MIMO-TWRC) when the nodes use analog beamforming. Following the amplify-and-forward (AF) strategy, the problem consists of finding the transmit and receive beamformers of the nodes and the relay, and the power allocated to each one, that achieve the boundary of the capacity region. We express the optimal node beamformers in terms of the relay beamformers, and show that the capacity region can be efficiently characterized using convex optimization techniques. Numerical examples are provided to illustrate the results of this paper, and to compare the capacity region achieved by analog beamforming against the conventional MIMO schemes that operate at the baseband.


two-way relay channel analog beamforming convex optimization capacity region 


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Copyright information

© ICST Institute for Computer Science, Social Informatics and Telecommunications Engineering 2012

Authors and Affiliations

  • Cristian Lameiro
    • 1
  • Alfredo Nazábal
    • 1
  • Fouad Gholam
    • 1
  • Javier Vía
    • 1
  • Ignacio Santamaría
    • 1
  1. 1.Communications Engineering Department (DICOM)University of CantabriaSantanderSpain

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