Abstract
Clock synchronization is one of the enabling technologies for Wireless Local Area Networks (WLAN). It is crucial to perform applications such as data fusion, location detection and energy conservation. IEEE 1588 Precision Time Protocol (PTP) is a widely used clock synchronization protocol, but its accuracy is affected by bidirectional asymmetric delays in WLAN. A detailed analysis of the generation mechanism and statistical properties of the bidirectional asymmetric delays in IEEE 802.11 WLAN is conducted firstly. Then, a Kalman filter is designed for delay filtering. And based on the Kalman filter, a clock servo system is proposed using pure software-based implementation of PTP for IEEE 802.11 WLAN. Finally, the effectiveness of the implementation is verified by experiments. Experimental results show that the implementation has the virtues of high synchronization accuracy, short convergence time and small deviation error.
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References
(2002). IEEE standard for a precision clock synchronization protocol for networked measurement and control systems. IEEE Std 1588–2002 (pp. i-144), doi:10.1109/IEEESTD.2002.94144.
(2007). IEEE standard for information technology—telecommunications and information exchange between systems—local and metropolitan area networks—specific requirements—part 11: Wireless local area network medium access control (MAC) and physical layer (PHY) specifications.
(2008) IEEE standard for a precision clock synchronization protocol for networked measurement and control systems. IEEE Std 1588–2008 (Revision of IEEE Std 1588–2002) pp. c1–269, doi:10.1109/IEEESTD.2008.4579760.
Akhlaq, M., & Sheltami, T.R. (2012). The recursive time synchronization protocol for wireless sensor networks. In IEEE Sensors Applications Symposium (SAS), 2012, IEEE, (pp. 1–6), doi:10.1109/sas.2012.6166318.
Akhlaq, M., & Sheltami, T. R. (2013). Rtsp: An accurate and energy-efficient protocol for clock synchronization in wsns. IEEE Transactions on Instrumentation and Measurement, 62(3), 578–589. doi:10.1109/TIM.2012.2232472.
Bang, Y., Han, J., Lee, K., Yoon, J., Joung, J., Yang, S., & Rhee, J.K. (2009). Wireless network synchronization for multichannel multimedia services. In Proceedings of the 11th International Conference on Advanced Communication Technology, (pp. 1073–1077).
Chaudhari, Q. M., Serpedin, E., & Qaraqe, K. (2008). On maximum likelihood estimation of clock offset and skew in networks with exponential delays. IEEE Transactions on Signal Processing, 56(4), 1685–1697. doi:10.1109/TSP.2007.910536.
Chen, J., Li, Y., Song, Y., & Chen, H. (2007). Hardware-assisted clock synchronization in IEEE 802. 11 wireless real-time application. In IET Conference on Wireless, Mobile and Sensor Networks, 2007. (CCWMSN07). IET, pp. (363–366).
Chiang, J.H., & Chiueh, T.c. (2009). Accurate clock synchronization for IEEE 802.11-based multi-hop wireless networks. In Proceedings of the 17th IEEE International Conference on Network Protocols, 2009. ICNP 2009. IEEE, (pp. 11–20).
Cho, H., Jung, J., Cho, B., Jin, Y., Lee, S.W., & Baek, Y. (2009). Precision time synchronization using IEEE 1588 for wireless sensor networks. In International Conference on Computational Science and Engineering, 2009. CSE’09. IEEE, 2, 579–586.
Cho, J. H., Kim, H., Wang, S., Lee, J., Lee, H., Hwang, S., et al. (2009). A novel method for providing precise time synchronization in a distributed control system using boundary clock. IEEE Transactions on Instrumentation and Measurement, 58(8), 2824–2829. doi:10.1109/TIM.2009.2016365.
Chu, W. K., Zhang, F. M., & Fan, X. G. (2007). Measurement of real-time performance of embedded linux systems. Systems Engineering and Electronics, 29(8), 1385–1401. doi:10.3321/j.issn:1001-506x.2007.08.041.
Cooklev, T., Eidson, J. C., & Pakdaman, A. (2007). An implementation of IEEE 1588 over IEEE 802.11b for synchronization of wireless local area network nodes. IEEE Transactions on Instrumentation and Measurement, 56(5), 1632–1639. doi:10.1109/TIM.2007.903640.
Correll, K., & Barendt, N. (2006). Design considerations for software only implementations of the IEEE 1588 precision time protocol. In Proceedings of the IEEE 1588 Standard for a Precision Clock Synchronization Protocol for Networked Measurement and Control Systems. Winterthur.
Djenouri, D., Merabtine, N., Mekahlia, F. Z., & Doudou, M. (2013). Fast distributed multi-hop relative time synchronization protocol and estimators for wireless sensor networks. Ad Hoc Networks, 11(8), 2329–2344.
Du, H. J., & Yang, N. (2007). Compression strategy for hash match algorithm in route list. Systems Engineering and Electronics, 29(11), 1945–1948. doi:10.3321/j.issn:1001-506x.2007.11.038.
Du, J., & Wu, Y.C. (2013). Fully distributed clock skew and offset estimation in wireless sensor networks. In IEEE International Conference on Acoustics, Speech and Signal Processing (ICASSP), 2013, IEEE, (pp. 4499–4503).
Eidson, J. C. (2006). Measurement, control, and communication using IEEE 1588 (Advances in Industrial Control). New York: Springer.
Elson, J., Girod, L., & Estrin, D. (2002). Fine-grained network time synchronization using reference broadcasts. In Proceedings of the 5th Symposium on Operating systems design and implementation, (pp. 147–163), doi:10.1145/844128.844143.
Exel, R. (2012). Clock synchronization in ieee 802.11 wireless lans using physical layer timestamps. In International IEEE Symposium on Precision Clock Synchronization for Measurement Control and Communication (ISPCS), 2012, IEEE, (pp. 1–6).
Ganeriwal, S., Kumar, R., & Srivastava, M.B. (2003). Timing-sync protocol for sensor networks. In Proceedings of the 1st International Conference on Embedded networked sensor systems, (pp. 138–149), doi:10.1145/958491.958508.
Huang, W., Quan, Y., & Chen, D. (2012). Improving broadcast efficiency in wireless sensor network time synchronization protocols. In Proceedings of the International Workshop on System Level Interconnect Prediction, ACM, (pp. 48–55), doi:10.1145/2347655.2347672.
Iwanicki, K., Steen, M., & Voulgaris, S. (2006). Gossip-based clock synchronization for large decentralized systems. In A. Keller & J. P. Martin-Flatin (Eds.), Proceedings of the second IEEE international workshop on self-managed networks, systems, and services, lecture notes in computer science (Vol. 3996, pp. 28–42). Berlin: Springer. doi:10.1007/11767886_3.
Jasperneite, J., Shehab, K., & Weber, K. (2004). Enhancements to the time synchronization standard IEEE-1588 for a system of cascaded bridges. In IEEE International Workshop on Factory Communication Systems, 2004. Proceedings. 2004, (pp. 239–244), doi:10.1109/WFCS.2004.1377716.
Jiang, Y., Fan, Y., & Chen, X. (2013). Time synchronization protocol for wireless sensor networks with nodemonitoring. Journal of Information and Computational Science, 10(4), 1213–1220. doi:10.12733/jics20101509.
Li, M. G., & Song, H. N. (2002). Research on computer clock synchronization technology. Journal of System Simulation, 14(4), 477–480. doi:10.3969/j.issn.1004-731X.2002.04.020.
Mahmood, A., Gaderer, G., & Loschmidt, P. (2010). Software support for clock synchronization over IEEE 802.11 wireless lan with open source drivers. In International IEEE Symposium on Precision Clock Synchronization for Measurement Control and Communication (ISPCS), 2010, IEEE, (pp. 61–66).
Mahmood, A., Gaderer, G., Trsek, H., Schwalowsky, S., & Kero, N. (2011). Towards high accuracy in IEEE 802.11 based clock synchronization using ptp. In International IEEE Symposium on Precision Clock Synchronization for Measurement Control and Communication (ISPCS), 2011, IEEE, (pp. 13–18).
Mahmood, A., Exel, R., & Sauter, T. (2014). Impact of hard-and software timestamping on clock synchronization performance over ieee 802.11. In Proceeding of the 10th IEEE Workshop on Factory Communication Systems (WFCS), 2014, IEEE (pp. 1–8).
Maroti, M., Kusy, B., Simon, G., & Ledeczi, A. (2004). The flooding time synchronization protocol. In Proceedings of the Second ACM Conference on Embedded Networked Sensor Systems, ACM Press, (pp. 39–49), doi:10.1145/1031495.1031501.
Sakurai, T., & Vu, H. L. (2007). MAC access delay of IEEE 802.11 DCF. IEEE Transactions on Wireless Communications, 6(5), 1702–1710. doi:10.1109/twc.2007.360372.
Shao, L., & Roy, S. (2005). Rate-one space-frequency block codes with maximum diversity for MIMO-OFDM. IEEE Transactions on Wireless Communications, 4(4), 1674–1687. doi:10.1109/twc.2005.850374.
Sheu, J. P., Chao, C. M., & Sun, C. W. (2007). A clock synchronization algorithm for multi-hop wireless ad hoc networks. Wireless Personal Communications, 43(2), 185–200. doi:10.1007/s11277-006-9217-4.
Shin, Y.J. & Lee, J.R. (2013). Time synchronization protocol in ad hoc network. In International Conference on Information Networking (ICOIN), 2013, IEEE, (pp. 375–378).
Snodgrass, T.E., & Stevens, J.A. (2008). Net formation-merging system and method. http://www.google.com.br/patents/US7430192, uS Patent 7,430,192.
Sun, Z.W. (2010). Research on the application of the high precision time synchronization of IEEE1588. Master’s thesis, National Time Service center, Chinese Academy of Sciences.
Sundararaman, U., Buy, U., & Kshemkalyani, A. D. (2005). Clock synchronization for wireless sensor networks: A survey. Ad Hoc Networks, 3(3), 281–323. doi:10.1016/j.adhoc.2005.01.002.
Wolf, B.J., Russell, H.B., & Wang, K.C. (2007). Synchronizing transmission schedules of partitioned ad hoc networks. In Proceedings of the IEEE Military Communications Conference, (pp. 1–7), doi:10.1109/milcom.2007.4455105.
Yang, H. D., & Deng, Y. (2008). Research on time synchronization in ad hoc networks. Computer Engineering and Design, 29(21), 5447–5450.
Ye, Q., Zhang, Y. & Cheng, L. (2005). A study on the optimal time synchronization accuracy in wirelesssensor networks. Computer Networks 48(4):549–566, doi:10.1016/j.comnet.2004.10.018, http://www.sciencedirect.com/science/article/pii/S138912860500006X
Yildirim, K. S., & Kantarci, A. (2013). Drift estimation using pairwise slope with minimum variance in wireless sensor networks. Ad Hoc Networks, 11(3), 765–777. doi:10.1016/j.adhoc.2012.09.003.
Zou, C., & Lu, Y. (2012). A time synchronization method for wireless sensor networks. In B. Liu, M. Ma, & J. Chang (Eds.), Information computing and applications, lecture notes in computer science (Vol. 7473, pp. 221–228). Berlin: Springer. doi:10.1007/978-3-642-34062-8_29..
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This work has been carried out at the Wireless Adaptive Laboratory of Control and Networks Institute, and supported by the Fundamental Research Project of Northwestern Polytechnical University. The authors thank the anonymous referees for devoting their time to reviewing the paper and their invaluable comments and suggestions, which significantly helped to improve the quality of the manuscript.
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Chen, W., Sun, J., Zhang, L. et al. An implementation of IEEE 1588 protocol for IEEE 802.11 WLAN. Wireless Netw 21, 2069–2085 (2015). https://doi.org/10.1007/s11276-015-0898-z
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DOI: https://doi.org/10.1007/s11276-015-0898-z