The Journal of Korean Institute of Communications and Information Sciences (한국통신학회논문지)

The Korean Institute of Commucations and Information Sciences (한국통신학회)
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Continuous Clock Synchronization and Packet Loss Tolerance Scheme for Enhancing Performance of Reference Broadcast Synchronization

RBS 성능향상을 위한 연속 클럭 동기화 및 패킷 손실 보상 기법

  • Received : 2014.04.25
  • Accepted : 2014.05.23
  • Published : 2014.05.31
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Abstract

Reference Broadcast Synchronization (RBS) is one of the most prominent synchronization protocols in wireless sensor nework. Given that the broadcasting medium is available, RBS can give very high accuracy of synchronization. However, RBS uses instantaneous synchronization and results in time discontinuity, which might cause serious faults in the distributed system. Also, RBS lacks packet loss tolerance, which brings about degraded performance in severe conditions of wireless channel. In this paper, the problem of time discontinuity in RBS is pointed out and the effect of packet loss on the performance of RBS is examined. Then, a continuous synchronization and a packet loss tolerance mechanism for RBS are proposed, and the result is verified through simulations.

Reference Broadcast Synchronization (RBS)는 무선 센서 네트워크 동기화에 가장 널리 사용되는 프로토콜이다. 공통의 브로드케스트 채널이 존재할 경우 RBS는 상당히 높은 동기화 성능을 보인다. 그러나 RBS는 순간 클럭 동기화 (Instantaneous Clock Synchronization) 방식을 사용기 때문에 동기화 시간에 순간적인 시간 간격이 발생하여 시스템의 불안정을 초래할 수 있다. 또한 RBS는 패킷 손실 보상 기능이 없어 무선 채널 환경이 열악한 경우 동기화 성능의 현저한 저하를 초래할 수 있다. 본 논문에서는 RBS의 순간 클럭 동기화에 의한 문제점과 패킷 손실이 BRS 동기화에 미치는 영향에 대해서 분석한다. 이러한 문제점을 해결하기 위하여 RBS를 위한 연속 클럭 동기화 방식과 패킷 손실 보상 방식을 제안하고, 모의실험을 통하여 제안 방식의 성능향상에 대해 검증하고자 한다.

Keywords

References

  1. T. Shon and K. Han, "Efficient mobile node authentication in WSN," J. KICS, vol. 35, pp. 833-839, May 2010.
  2. Y. I. Kim, B.-G. Choi, H. Lim, and M. Y. Chung, "Traffic_adaptive synchronized MAC protocol for wireless sensor networks," in Proc. KICS, pp. 861-862, Jun. 2009.
  3. U. Jeong and M. Kang, "Design of structures monitoring system using synchronized wireless sensor networks," in Proc. KICS, pp. 295-296, Nov. 2009.
  4. J. Elson, L. Girod, and D. Estrin, "Fine-grained network time synchronization using reference broadcasts," in Proc. OSDI, vol. 36, pp. 147-163, Boston, Massachusetts, Dec. 2002.
  5. M. Mock, R. Frings, E. Nett, and S. Trikaliotis, "Continuous clock synchronization in wireless real-time applications," in Proc. IEEE SRDS, pp. 125-132, Nurnberg, Oct. 2000.
  6. B. Sundararaman, U. Buy, and A. D. Kshemkalyani, "Clock synchronization for wireless sensor networks: a survey," J. Ad Hoc Networks (Elsevier), vol. 3, pp. 281-323, Mar. 2005. https://doi.org/10.1016/j.adhoc.2005.01.002
  7. L. Lamport, "Time, clocks, and the ordering of events in a distributed system," Mag. Communications ACM, vol. 21, no. 7, pp. 558-565, Jul. 1978. https://doi.org/10.1145/359545.359563
  8. M. Ryu and S. Hong, "Revisiting clock synchronization problems: static and dynamic constraint transformations for correct timing enforcement," Technical Report No. SNU-EETR-1998-3, Seoul National Univ., South Korea, Sept. 1998.
  9. J. Zhao and R. Govindan, "Understanding packet delivery performance in dense wireless sensor networks," in Proc. SenSys'03, LA, California, pp. 1-13, Nov. 2003.
  10. J. Shin, R. Umakishore, and M. Ammar, "On improving the reliability of packet delivery in dense wireless sensor networks," in Proc. ICCCN, pp. 718-723, Honolulu, HI, Aug. 2007.
  11. J. L. Welch and N. Lynch, "A new faulttolerant algorithm for clock synchronization," J. Information Computation, vol. 77, no. 1, pp. 1-36, Apr. 1988. https://doi.org/10.1016/0890-5401(88)90043-0