Cooperative communication can improve the performance of communication systems under multi-path fading conditions through relaying. Increasing the number of relays will also boost the performance of the system, but since relays transmit through orthogonal channels, this improvement is obtained at the cost of bandwidth or rate of the system. Best relay selection is a well-known technique to achieve full order of diversity and use bandwidth efficiently in a cooperative two-hop multi-relay network. A new beamforming at the relay is proposed that selects the best two among several relays and then the selected relays forward their detected symbols in a common channel to the destination. For achieving full diversity order at the destination, a modified maximal ratio combining detector is proposed. In the proposed beamforming scheme, the phase of the selected relays is adjusted in such a way to compensate the channel between the relays and the destination and achieve acceptable performance at the receiving end. The selected relays require two-bit quantised phase information of the channel gain between the relay and the destination, which can be sent to the relay by the destination. It is shown that the proposed method achieves full diversity order and has considerable performance gain in comparison with the best relay selection method.

References

1. 1)
  - M.M. Abdallah , H.C. Papadopoulos . Beamforming algorithms for information relaying in wireless sensor networks. IEEE Trans. Signal Process. , 10 , 4772 - 4784
2. 2)
  - F. Onat , A. Adinoyi , Y. Fan , H. Yanikomeroglu , J. Thompson , I. Marsland . Threshold selection for SNR-based selective digital relaying in cooperative wireless networks. IEEE Trans. Wirel. Commun. , 4226 - 4237
3. 3)
  - 16. Su, W., Sadek, A., Liu, K.: ‘SER performance analysis and optimum power allocation for decode-and-forward cooperation protocol in wireless networks’. 2005 IEEE Wireless Communications and Networking Conference, 2005, vol. 2, pp. 984–989.
4. 4)
  - A.S. Ibrahim , A.K. Sadek , W. Su , K.J.R. Liu . Cooperative communications with relay-selection: when to cooperate and whom to cooperate with?. IEEE Trans. Wirel. Commun. , 7 , 2814 - 2827
5. 5)
  - A. Sendonaris , E. Erkrip , B. Aazhang . User cooperation diversity – Part II: implementation aspects and performance analysis. IEEE Trans. Commun. , 11 , 1939 - 1948
6. 6)
  - 19. Bastami, A., Olfat, A.: ‘Optimal SNR-based selection relaying scheme with M-ary modulations in cooperative wireless networks’, IET Commun., 2011, 5, (6), pp. 797–810 (doi: 10.1049/iet-com.2010.0233).
7. 7)
  - J.N. Laneman , G.W. Wornell . Distributed space-time-coded protocols for exploiting cooperative diversity in wireless networks. IEEE Trans. Inf. Theory , 10 , 2415 - 2425
8. 8)
  - 13. Xiong, K., Fan, P., Xu, Z., Yang, H.-C., Ben Letaief, K.: ‘Optimal cooperative beamforming design for MIMO decode-and-forward relay channels’, IEEE Trans. Signal Process., 2014, 62, (6), pp. 1476–1489 (doi: 10.1109/TSP.2014.2298380).
9. 9)
  - 5. Zhou, N., Chen, X., Li, C., Xue, Z.: ‘Secrecy rate of two-hop AF relaying networks with an untrusted relay’, Wirel. Pers. Commun., 2014, 75, (1), pp. 119–129 (doi: 10.1007/s11277-013-1351-1).
10. 10)
  - 11. Barriac, G., Mudumbai, R., Madhow, U.: ‘Distributed beamforming for information transfer in sensor networks’. Third Int. Symp. Information Processing in Sensor Networks, 2004. IPSN 2004, April 2004, pp. 81–88.
11. 11)
  - 6. Yan, J., Li, J., Zhao, L.: ‘Joint user scheduling and power allocation with quality of service guarantees in downlink distributed antennas system’, IET Commun., 2014, 8, (3), pp. 299–307 (doi: 10.1049/iet-com.2013.0520).
12. 12)
  - 20. Bastami, A., Olfat, A.: ‘Selection relaying schemes for cooperative wireless networks with adaptive modulation’, IEEE Trans. Veh. Technol., 2011, 60, (4), pp. 1539–1558 (doi: 10.1109/TVT.2011.2132810).
13. 13)
  - A. Sendonaris , E. Erkip , B. Aazhang . User cooperation diversity. Two Parts. IEEE Trans. Commun. , 1927 - 1948
14. 14)
  - 15. Koyuncu, E., Jing, Y., Jafarkhani, H.: ‘Distributed beamforming in wireless relay networks with quantized feedback’, Sel. IEEE J. Areas Commun., 2008, 26, (8), pp. 1429–1439 (doi: 10.1109/JSAC.2008.081009).
15. 15)
  - Y. Jing , H. Jafarkhani . Network beamforming using relays with perfect channel information. IEEE Trans. Inf. Theory , 6 , 2499 - 2517
16. 16)
  - 14. Qian, M., Liu, C., Fu, Y.: ‘Distributed beamforming designs to improve physical layer security in wireless relay networks’, EURASIP J. Adv. Signal Process., 2014, 2014, (1), pp. 1–10 (doi: 10.1186/1687-6180-2014-1).
17. 17)
  - A.H. Bastami , A. Olfat . Optimal SNR-based selection relaying scheme in multi-relay cooperative networks with distributed space–time coding. IET Commun. , 6 , 619 - 630
18. 18)
  - A. Ribeiro , X. Cai , G.B. Giannakis . Symbol error probabilities for general cooperative links. IEEE Trans. Wirel. Commun. , 3 , 1264 - 1273
19. 19)
  - J.N. Laneman , D.N.C. Tse , G.W. Wornell . Cooperative diversity in wireless networks: efficient protocols and outage behavior. IEEE Trans. Inf. Theory , 12 , 3062 - 3080
20. 20)
  - 9. Bletsas, A., Lippnian, A., Reed, D.: ‘A simple distributed method for relay selection in cooperative diversity wireless networks, based on reciprocity and channel measurements’. 2005 IEEE 61st Vehicular Technology Conference, 2005. VTC 2005-Spring, 2005, vol. 3, pp. 1484–1488.
21. 21)
  - A. Adinoyi , Y. Fan , H. Yanikomeroglou , H.V. Poor , F. Al-Shaalan . Performance of selection relaying and cooperative diversity. IEEE Trans. Wirel. Commun. , 12 , 5790 - 5795
22. 22)
  - 1. Laneman, J.: ‘Cooperative diversity in wireless networks: algorithms and architectures’, Ph.D. dissertation, Massachusetts Institute of Technology, 2002.
23. 23)
  - N.C. Beaulieu , J. Hu . A closed-form expression for the outage probability of decode-and-forward relaying in dissimilar Rayleigh fading channels. IEEE Commun. Lett. , 12 , 813 - 815

Joint relay selection and cooperative beamforming in two-hop multi-relay decode-and-forward networks

References

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