Journal of information and communication convergence engineering

The Korea Institute of Information and Commucation Engineering (한국정보통신학회)
권호 표지

The Modified Backoff Algorithm to reduce the number of collisions in the IEEE 802.11 Networks

  • Published : 2008.06.30
Download PDF
⟨ Previous Next ⟩

Abstract

In recent years, wireless ad hoc networks have become increasingly popular in both military and civilian applications due to their capability of building networks without the need for a pre-existing infrastructure. Recently, IEEE 802.11 Task Group e has been working on a new mechanism, the Enhanced Distributed Coordination Function (EDCF), to enhance the performance of 802.11 DCF. However, EDCF only reduces the internal collisions within a station, and external collisions between stations remain high in ad-hoc networks. In this paper, we propose to adopt an adaptive backoff window control technique, based on a dynamic value of the initial value of the range in which the backoff is chosen, so the backoff timer is randomly chosen in the range (InitRng, CW-1). We use ns-2 simulation to evaluate the throughput of our scheme. Results show that the throughput is improved for our scheme compared to the original DCF due to the reduced the number of collisions.

Keywords

References

  1. IEEE standard 802.11-1999, Part II : Wireless LAN Medium Access Control(MAC) and Physical Layer(PHY) specifications, 1999
  2. IEEE 802.11e WG, Medium Access Control (MAC) Enhancements for Quality of Service, IEEE 802.11e/D2.0, Nov. 2001
  3. M. Benveniste, "Summary of Features Proposed for the Enhanced-DCF Wireless MAC Protocol," IEEE Document, 802.11-01/003, January 2001
  4. G. Bianchi, "Performance analysis of the IEEE 802.11 distributed coordination function," IEEE J. Sel. Areas Commun., vol. 18, no. 3, pp. 535-547, Mar. 2000 https://doi.org/10.1109/49.840210
  5. E. Ziouva and T. Antonakopoulos, "CSMA/CA performance under high traffic conditions: Throughput and delay analysis," Comput. Commun., vol. 25, no. 3, pp. 313-321, Feb. 2002 https://doi.org/10.1016/S0140-3664(01)00369-3
  6. Y.C. Tay and K.C. Chua, "A capacity analysis for the IEEE 802.11 MAC Protocol", Wireless Networks 7, pp 159-171, 2001 Kluwer Academic Publishers https://doi.org/10.1023/A:1016637622896
  7. H. S. Chhaya and S. Gupta, "Performance modeling of asynchronous data transfer methods of IEEE 802.11 MAC Protocol", Wireless Networks 3, pp 217-234, 1997 https://doi.org/10.1023/A:1019109301754
  8. G. Bianchi, L. Fratta, and M. Oliveri, "Performance evaluation and enhancement of the CSMA/CAMAC protocol for 802.11 wireless LANs," in Proc. PIMRC 1996, Taipei, Taiwan, Oct. 1996, pp. 392-396
  9. J. Weinmiller, H. Woesner, J. P. Ebert, and A. Wolisz, Analyzing and tuning the distributed coordination function in the IEEE 802.11 DFWMAC draft standard," in Proc. MASCOT'96, San Jose, CA, Feb. 1996
  10. G. Chesson, A. Singla, W. Diepstraten, and H. Tenniusen, et al, "VDCF Proposed Draft Text," IEEE Document, 802.11-01/131, March 2001
  11. NS-2 simulator, http://www.isi.edu/nsnam/ns/, April 2002