Mobile Networks and Applications

, Volume 23, Issue 6, pp 1525–1538 | Cite as

Cognitive Heterogeneous Networks with Unreliable Backhaul Connections

  • Huy T. Nguyen
  • Dac-Binh Ha
  • Sang Quang Nguyen
  • Won-Joo HwangEmail author


To enhance the spectrum scarcity of cooperative heterogeneous networks (HetNets) with unreliable backhaul connections, we examine the impact of cognitive spectrum sharing over multiple small-cell transmitters in Nakagami-m fading channels. In this system, the secondary transmitters are connected to macro-cell via wireless backhaul links and communicate with the secondary receiver by sharing the same spectrum with the primary user. Integrating cognitive radio (CR) network into the system, we address the combined power constraints: 1) the peak interference power at the primary user and 2) the maximal transmit power at the secondary transmitters. In addition, to exclude the signaling overhead for exchanging channel-state-information (CSI) at the transmitters, the selection combining (SC) protocol is assumed to employ at the receivers. To evaluate the performance, we first derive the closed-form statistics of the end-to-end signal-to-noise (SNR) ratio, from which the exact outage probability, ergodic capacity and symbol error rate expressions are derived. To reveal further insights into the effective unreliable backhaul links and the diversity of fading parameters, the asymptotic expressions are also attained. The two interesting non-cooperative and Rayleigh fading scenarios are also investigated. Numerical results are conducted to verify the performance of the considered system via Monte-Carlo simulations.


Cognitive radio network Cooperative system Wireless backhaul Selection combining Maximum transmit power Peak interference power Nakagami-m fading 


  1. 1.
    Chia S, Gasparroni M, Brick P (2009) The next challenge for cellular networks: Backhaul. IEEE Microw Mag 10:5CrossRefGoogle Scholar
  2. 2.
    Andrews JG (2013) Seven ways that HetNets are a cellular paradigm shift. IEEE Commun Mag 51(3):136–144CrossRefGoogle Scholar
  3. 3.
    Tipmongkolsilp O, Zaghloul S, Jukan A (2011) The evolution of cellular backhaul technologies: Current issues and future trends. IEEE Commun Surv Tuts 13(1):97–113CrossRefGoogle Scholar
  4. 4.
    Coldrey M, Koorapaty H, Berg J-E, Ghebretensae Z, Hansryd J, Derneryd A, Falahati S (2012) Small-cell wireless backhauling: A non-line-of-sight approach for point-to-point microwave links. In: Proceedings of IEEE Vehicular Technology of Conference, Quebec City, pp 1–5Google Scholar
  5. 5.
    Pantisano F, Bennis M, Saad W, Debbah M, Latva-Aho M (2012) On the impact of heterogeneous backhauls on coordinated multipoint transmission in femtocell networks. In: Proceedings IEEE International Conference on Communications, Ottawa, pp 5064–5069Google Scholar
  6. 6.
    Mayer Z, Li J, Papadogiannis A, Svensson T (2013) On the impact of backhaul channel reliability on cooperative wireless networks. In: Proceedings IEEE International Conference on Communications, Budapest, pp 5284–5289Google Scholar
  7. 7.
    Khan T, Orlik P, Kim KJ, Heath RW (2015) Performance analysis of cooperative wireless networks with unreliable backhaul links. IEEE Commun Lett 19(8):1386–1389CrossRefGoogle Scholar
  8. 8.
    Kim KJ, Orlik P, Khan T (2016) Performance analysis of finite-sized co-operative systems with unreliable backhauls. IEEE Trans Wirel Commun 15(7):5001–5015CrossRefGoogle Scholar
  9. 9.
    Peng M, Liu Y, Wei D, Wang W, Chen H-H (2011) Hierarchical cooperative relay based heterogeneous networks. IEEE Wireless Commun 3:18Google Scholar
  10. 10.
    Letaief KB, Zhang W (2009) Cooperative communications for cognitive radio networks. Proc IEEE 97 (5):878–893CrossRefGoogle Scholar
  11. 11.
    Al-Qahtani FS, Zhong C, Alnuweiri HM (2015) Opportunistic relay selection for secrecy enhancement in cooperative networks. IEEE Trans Commun 63(5):1756–1770CrossRefGoogle Scholar
  12. 12.
    Wang L, Yang N, Elkashlan M, Yeoh PL, Yuan J (2014) Physical layer security of maximal ratio combining in two-wave with diffuse power fading channels. IEEE Trans Inf Forensic Secur 9(2):247–258CrossRefGoogle Scholar
  13. 13.
    Kim KJ, Duong TQ, Tran X-N (2012) Performance analysis of cognitive spectrum-sharing single-carrier systems with relay selection. IEEE Trans Signal Process 60(12):6435–6449MathSciNetCrossRefGoogle Scholar
  14. 14.
    Andrews JG, Buzzi S, Choi W, Hanly SV, Lozano A, Soong AC, Zhang JC (2014) What will 5G be? IEEE J Sel Areas Commun 32(6):1065–1082CrossRefGoogle Scholar
  15. 15.
    Zhang R, Liang Y-C (2008) Exploiting multi-antennas for opportunistic spectrum sharing in cognitive radio networks. IEEE J Sel Top Signal Process 2(1):88–102CrossRefGoogle Scholar
  16. 16.
    Niyato D, Hossain E (2008) Competitive pricing for spectrum sharing in cognitive radio networks: Dynamic game, inefficiency of nash equilibrium, and collusion. IEEE J Sel Areas Commun 26(1):192–202CrossRefGoogle Scholar
  17. 17.
    Duong TQ, da Costa DB, Elkashlan M, Bao VNQ (2012) Cognitive amplify-and-forward relay networks over Nakagami-m fading. IEEE Trans Veh Technol 61(5):2368–2374CrossRefGoogle Scholar
  18. 18.
    Deng Y, Wang L, Elkashlan M, Kim KJ, Duong TQ (2015) Generalized selection combining for cognitive relay networks over Nakagami-m fading. IEEE Trans Signal Process 63(8):1993–2006MathSciNetCrossRefGoogle Scholar
  19. 19.
    Xia M, Aissa S (2012) Cooperative AF relaying in spectrum-sharing systems: performance analysis under average interference power constraints and Nakagami-m fading. IEEE Trans Commun 60(6):1523–1533CrossRefGoogle Scholar
  20. 20.
    Duong TQ, Bao VNQ, Alexandropoulos GC, Zepernick H-J (2011) Cooperative spectrum sharing networks with AF relay and selection diversity. IET Electron Lett 47(20):1149–1151CrossRefGoogle Scholar
  21. 21.
    Duong TQ, Bao VNQ, Zepernick H-J (2011) Exact outage probability of cognitive AF relaying with underlay spectrum sharing. IET Electron Lett 47(17):1001–1002CrossRefGoogle Scholar
  22. 22.
    Duong TQ, Bao VNQ, Tran H, Alexandropoulos GC, Zepernick H-J (2012) Effect of primary network on performance of spectrum sharing AF relaying. IET Electron Lett 48(1):25–27CrossRefGoogle Scholar
  23. 23.
    ElSawy H, Hossain E, Kim DI (2013) HetNets with cognitive small cells: User offloading and distributed channel access techniques. IEEE Commun Mag 51(6):28–36CrossRefGoogle Scholar
  24. 24.
    ElSawy H, Hossain E (2014) Two-tier HetNets with cognitive femtocells: Downlink performance modeling and analysis in a multichannel environment. IEEE Trans Mob Comput 13(3):649–663CrossRefGoogle Scholar
  25. 25.
    Adhikary A, Caire G (2012) On the coexistence of macrocell spatial multiplexing and cognitive femtocells. In Proceedings of 2012 International Conference on Communications, Ottawa, Canada, Jul. 2012 pp 6830?6834Google Scholar
  26. 26.
    Chen Z, Yuan J, Vucetic B (2005) Analysis of transmit antenna selection/maximal-ratio combining in Rayleigh fading channels. IEEE Trans Veh Technol 54(4):1312–1321CrossRefGoogle Scholar
  27. 27.
    Guimarães FRV, da Costa DB, Tsiftsis TA, Cavalcante CC, Karagiannidis GK (2014) Multiuser and multirelay cognitive radio networks under spectrum-sharing constraints. IEEE Trans Veh Technol 63(1):433–439CrossRefGoogle Scholar
  28. 28.
    Lodhi A, Said F, Dohler M, Aghvami AH (2008) Closed-form symbol error probabilities of STBC and CDD MC-CDMA with frequency-correlated subcarriers over Nakagami- m fading channels. IEEE Trans Veh Technol 57(2):962–973CrossRefGoogle Scholar
  29. 29.
    Kim KJ, Duong TQ, Elkashlan M, Yeoh PL, Poor HV, Lee MH (2013) Spectrum sharing single-carrier in the presence of multiple licensed receivers. IEEE Trans Wirel Commun 12(10):5223–5235CrossRefGoogle Scholar
  30. 30.
    Duong TQ, Yeoh PL, Bao VNQ, Elkashlan M, Yang N (2012) Cognitive relay networks with multiple primary transceivers under spectrum-sharing. IEEE Signal Process Lett 19(11):741–744CrossRefGoogle Scholar
  31. 31.
    Kim KJ, Khan T, Orlik P (2016) Performance analysis of cooperative systems with unreliable backhauls and selection combining. In: IEEE Transactions on Vehicular Technology. in pressGoogle Scholar
  32. 32.
    Tsiftsis TA, Karagiannidis GK, Sagias NC, Kotsopoulos SA (2006) Performance of MRC diversity receivers over correlated Nakagami-m fading channels. In: Proceedings Communication Systems, Networks and Digital Signal Processing, Patras , pp 84–88Google Scholar
  33. 33.
    Cavers JK (2000) Single-user and multiuser adaptive maximal ratio transmission for Rayleigh channels. IEEE Trans Veh Technol 49(6):2043–2050CrossRefGoogle Scholar
  34. 34.
    Duong TQ, Da Costa DB, Tsiftsis TA, Zhong C, Nallanathan A (2012) Outage and diversity of cognitive relaying systems under spectrum sharing environments in Nakagami-m fading. IEEE Commun Lett 16 (12):2075–2078CrossRefGoogle Scholar
  35. 35.
    Duong TQ, Alexandropoulos GC, Zepernick H-J, Tsiftsis TA (2011) Orthogonal space-time block codes with CSI-assisted amplify-and-forward relaying in correlated Nakagami-m fading channels. IEEE Trans Veh Technol 60(3):882–889CrossRefGoogle Scholar
  36. 36.
    Gradshteyn IS, Ryzhik IM (2007) Table of integrals, series and products. Academic Press, New YorkzbMATHGoogle Scholar
  37. 37.
    Suraweera HA, Smith PJ, Shafi M (2010) Capacity limits and performance analysis of cognitive radio with imperfect channel knowledge. IEEE Trans Veh Technol 59(4):1811–1822CrossRefGoogle Scholar
  38. 38.
    Prudnikov A, Brychkov YA, Marichev O (1998) Integrals and Series, vol. I: Elementary Functions. Gordon and Breach, LondonzbMATHGoogle Scholar

Copyright information

© Springer Science+Business Media, LLC 2017

Authors and Affiliations

  1. 1.Department of Information and Communication SystemInje UniversityGimhaeKorea
  2. 2.Duy Tan UniversityDa NangVietnam

Personalised recommendations