Analyzing space/capacity tradeoffs of cooperative wireless networks using a probabilistic model of interference

ABSTRACT

Interference limits throughput in wireless networks. To protect themselves against interference, many wireless protocols create areas around receivers in which no node is allowed to transmit. If such an exclusion area is small, more transmissions can proceed simultaneously but observe higher interference, creating a tradeoff between network capacity and link capacity.

Link capacity can be improved by cooperative diversity techniques, exploiting stochastically independent retransmissions by a relay node. But for this relay to work, it has to receive the original transmission, again consuming space. Hence, cooperation influences the network/link capacity tradeoff as it invests more space to increase link capacity.

This paper characterizes the tradeoff when cooperation is used. We derive a closed-form solution for the expected total interference caused by the k-closest nodes. We use this result to reformulate the outage capacity equations for direct, Non-Cooperative Relaying (NCR), and Selection Decode-and-Forward (SDF) transmission as functions of exclusion areas. We find that by using SDF, capacity gains over direct transmission are highest when exclusion areas are smallest. This result suggests that cooperation is a key technique to improve capacity in networks with powerful/sophisticated receivers that are able to cope well with high interference.

References

1. J. Andrews, S. Shakkottai, R. Heath, N. Jindal, M. Haenggi, R. Berry, D. Guo, M. Neely, S.Weber, S. Jafar, and A. Yener. Rethinking information theory for mobile ad hoc networks. IEEE Commun. Mag., 46(12):94--101, Dec. 2008.
2. J. H. Conway and R. K. Guy. The Book of Numbers. Springer, 1995.
3. L. M. Feeney, D. Hollos, M. Kubisch, S. Mengesha, and H. Karl. A geometric derivation of the probability of finding a relay in multi-rate networks. In Proc. 3rd IFIP-TC6 Networking Conf., May 2004.
4. P. Gupta and P. R. Kumar. The capacity of wireless networks. IEEE Trans. Inf. Theory, 46(2):388--404, Mar. 2000.
5. M. Haenggi. On distances in uniformly random networks. IEEE Trans. Inf. Theory, 51(10):3584--3586, Oct. 2005.
6. J. N. Laneman, D. N. C. Tse, and G. W. Wornell. Cooperative diversity in wireless networks: Efficient protocols and outage behavior. IEEE Trans. Inf. Theory, 50(12):3062--3080, Dec. 2004.
7. D. Munoz-Rodriguez, O. Uribe-Arambula, C. Vargas, and H. Maturino. Interference bounds in power controlled systems. IEEE Commun. Lett., 4(12):398--401, Dec. 2000.
8. A. Nosratinia, T. E. Hunter, and A. Hedayat. Cooperative communication in wireless networks. IEEE Commun. Mag., 42(10):74--80, Oct. 2004.
9. A. Ozgur, O. Leveque, and D. N. C. Tse. Hierarchical cooperation achieves optimal capacity scaling in ad hoc networks. IEEE Trans. Inf. Theory, 53(10):3549--3572, Oct. 2007.
10. D. Tse and P. Viswanath. Fundamentals of Wireless Communication. Cambridge University Press, May 2005.
11. S. Valentin, H. S. Lichte, H. Karl, I. Aad, L. Loyola, and J. Widmer. Opportunistic relaying vs. selective cooperation: Analyzing the occurrence-conditioned outage capacity. In Proc. 11th Int. Symp. Modeling, Anal. and Simulation of Wireless and Mobile Syst., pages 193--202, Oct. 2008.

Index Terms

• Networks

  • Network types

    • Mobile networks

    • Wireless access networks

• Security and privacy

  • Cryptography

    • Mathematical foundations of cryptography

• Theory of computation

  • Computational complexity and cryptography

    • Communication complexity