Optimal relay assignment for cooperative communications

ABSTRACT

Recently, cooperative communications, in the form of keeping each node with a single antenna and having a node exploit a relay node's antenna, is shown to be a promising approach to achieve spatial diversity. Under this communication paradigm, the choice of relay node plays a significant role in the overall system performance. In this paper, we study the relay node assignment problem in a network environment, where multiple source-destination pairs compete for the same pool of relay nodes in the network. The main contribution of this paper is the development of a polynomial time algorithm to solve this problem. A key idea in this algorithm is a "linear marking" mechanism, which is able to offer a linear complexity for each iteration. We give a formal proof of optimality for this algorithm. We also show several attractive properties associated with this algorithm.

REFERENCES

• 1: B. Aazhang, R. S. Blum, J. N. Laneman, K. J. R. Liu, W. Su, and A. Wittneben, IEEE Journal on Selected Areas in Communications - Special Issue on Cooperative Communications and Networking,vol. 25, no. 2, Feb. 2007.
• 2: A. Bletsas, A. Khisti, D. Reed, and A. Lippman, "A simple cooperative diversity method based on network path selection," IEEE Journal on Selected Areas in Communications, vol. 24, no. 3, pp. 659--672, March 2006.
• 3: J. Cai, S. Shen, J. W. Mark, and A. S. Alfa, "Semi-distributed user relaying algorithm for amplify-and-forward wireless relay networks," to appear in IEEE Transactions on Wireless Communications.
• 4: T. M. Cover and A. EL Gamal,"Capacity theorems for the relay channel," IEEE Transactions on Information Theory, vol. 25, issue 5, pp. 572--584, 1979.
• 5: G. Kramer, R. Berry, A. El Gamal, H. El Gamal, M. Franceschetti, M. Gastpar,and J. N. Laneman, IEEE Transactions on Information Theory - Special Issue on Models, Theory, and Codes for Relaying and Cooperation in Communication Networks, vol. 53, no. 10, Oct. 2007.
• 6: 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, Dec. 2004.
• 7: T. C.-Y. Ng and W. Yu, "Joint optimization of relay strategies and resource allocations in cooperative cellular networks," IEEE Journal on Selected Areas in Communications, vol. 25, no. 2, pp. 328--339, Feb. 2007.
• 8: 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.
• 9: E. C. van der Meulen, "Three terminal communication channels," Advances in Applied Probability, vol. 3, pp. 120--154, 1971.
• 10: Y. Zhao, R. S. Adve, and T. J. Lim, "Improving amplify-and-forward relay networks: optimal power allocation versus selection,"in Proc. IEEE International Symposium on Information Theory,pp. 1234--1238, Seattle, WA, July 9-14, 2006.

INDEX TERMS

Primary Classification:
  C. Computer Systems Organization
  C.2 COMPUTER-COMMUNICATION NETWORKS
      C.2.1 Network Architecture and Design
          Subjects: Wireless communication

General Terms:
Algorithms

Keywords:
cooperative communications, network capacity, wireless networks