Impact of Direct Communications on the Performance of Cooperative Spectrum-Sharing with Two-Way Relays and Maximal Ratio Combining

  • Tu Lam Thanh
  • Tiep M. HoangEmail author
  • Vo Nguyen Quoc Bao
  • Hien M. Nguyen
Conference paper
Part of the Lecture Notes of the Institute for Computer Sciences, Social Informatics and Telecommunications Engineering book series (LNICST, volume 257)


In this paper, we investigate a three-phase two-way (TW) amplify-and-forward (AF) relaying for cognitive radio networks. By utilizing the direct communications, the end user can employ maximal ratio combining to achieve the full diversity. We derive the closed-form and asymptotic expressions for user and system outage probabilities which allow us to highlight the advantage of cooperative cognitive communications. The numerical results, obtained through compact forms of these outage probabilities, yield that the cognitive TW AF relaying scheme can significantly enhance the reliability of unlicensed networks in which the transmit power at each secondary user is strictly governed.



This work was supported by the Newton Prize 2017 and by a Research Environment Links grant, ID 339568416, under the Newton Programme Vietnam partnership. The grant is funded by the UK Department of Business, Energy and Industrial Strategy (BEIS) and delivered by the British Council. For further information, please visit


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Copyright information

© ICST Institute for Computer Sciences, Social Informatics and Telecommunications Engineering 2019

Authors and Affiliations

  • Tu Lam Thanh
    • 1
  • Tiep M. Hoang
    • 2
    Email author
  • Vo Nguyen Quoc Bao
    • 3
  • Hien M. Nguyen
    • 4
  1. 1.Universite Paris-SaclayParisFrance
  2. 2.Queen’s University BelfastBelfastUK
  3. 3.Posts and Telecommunications Institute of TechnologyHo Chi Minh CityVietnam
  4. 4.Duy Tan UniversityDuy TanVietnam

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