Adaptive Decode-and-Forward Cooperative Networks with Multiple Relay Nodes

  • Vu, Ha Nguyen (Department of Electrical Engineering, University of Ulsan) ;
  • Kong, Hyung-Yun (Department of Electrical Engineering, University of Ulsan)
  • Received : 2010.07.06
  • Accepted : 2010.11.22
  • Published : 2011.03.31


We propose an adaptive cooperative scheme with a multi-relay node that achieves high bandwidth efficiency and achieves better SEP performance. In the proposed protocol, if the quality of the direct channel is better than that of the all channels from relays to destination, the source will transmit directly to the destination. Otherwise, the source broadcasts the signal and then a potential relay will be chosen to help the source. A re-transmission will also occur if the potential relay cannot be detected. The spectral efficiency is first derived by calculating the probability of each mode, i.e., direct and cooperation transmission. Subsequently, the SEP performance of M-PSK modulation for the scheme is analyzed by considering each event where the source transmits data to the destination. Finally, the obtained analytical results are verified through computer simulations.


  1. A. Sendonaris, E. Erkip, and B. Aazhang, "User cooperation diversity - part i: System description," IEEE Transactions on Communications, vol. 51, no. 11, pp. 1927-1938, Nov. 2003.
  2. J. N. Laneman, D. N. C. Tse, and G. W. Wornell, "Cooperative diversity in wireless networks: Efficient protocols and outage behavior," IEEE Transactions on Information Theory, vol. 50, no. 12, pp. 3062-3080, 2004.
  3. A. Bletsas, A. Khisti, D. P. Reed, and A. Lippman, "A simple cooperative diversity method based on network path selection," IEEE Journal on Select Areas in Communications, vol. 24, no. 3, pp. 659-672, Mar. 2006.
  4. I. H. Lee, D. Kim, "Ber analysis for decode-and-forward relaying in dissimilar rayleigh fading channels," IEEE Communications Letters, vol. 11, no. 1, pp. 52-54, 2007.
  5. A. S. Ibrahim, A. K. Sadek, S. Weifeng, and K. J. R. Liu, "Cooperative communications with partial channel state information: When to cooperate?," in Global Telecommunications Conference, 2005. GLOBECOM '05. IEEE, pp. 3068-3072, 2005.
  6. H. N. Vu, H. Y. Kong, "Adaptive decode-and-forward cooperative networks with limited feedback," IEICE Communication Letter, vol. E93.B, no. 2, pp. 4-7, 2010.