Frontiers of Optoelectronics >
Joint timing and frequency synchronization in coherent optical OFDM systems
Received date: 01 Jun 2018
Accepted date: 28 Jan 2019
Published date: 15 Mar 2019
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In this paper, we review our joint timing and frequency synchronization algorithms in coherent optical orthogonal frequency division multiplexing (CO-OFDM) systems. We first present a timing estimation method by designing the pattern of the training symbol, whose timing metric has a sharp and clear peak, to ensure accurate timing offset (TO) estimation performance. Then we provide both data-aided (DA) and blind (BL) approaches to estimate the carrier frequency offset (CFO). For the DA algorithm, we utilize the same training symbol structure as the timing estimation does, while for the BL algorithm, we utilize the zero-subcarrier power (ZSP) to achieve full-range CFO estimation. Note that our joint timing and frequency synchronization approaches require only one OFDM symbol, which ensure not only the data transmission efficiency, but also the TO and CFO estimation performance. A modified BL ZSP algorithm is proposed to further improve the CFO estimation performance by taking the power average over a series of OFDM symbols. The effectiveness of the TO estimation algorithm, and both the DA and BL CFO estimation algorithms are verified and demonstrated in both simulations and experiments.
Xinwei DU , Pooi-Yuen KAM , Changyuan YU . Joint timing and frequency synchronization in coherent optical OFDM systems[J]. Frontiers of Optoelectronics, 2019 , 12(1) : 4 -14 . DOI: 10.1007/s12200-019-0868-7
1 |
Shieh W, Djordjevic I. OFDM for Optical Communications. Burlington: Academic Press, 2009
|
2 |
Shieh W, Athaudage C. Coherent optical orthogonal frequency division multiplexing. Electronics Letters, 2006, 42(10): 587–589
|
3 |
Hara S, Prasad R. Multicarrier Techniques for 4G Mobile Communiations. Norwood, MA: Artech House, 2003
|
4 |
Pollet T, Van Bladel M, Moeneclaey M. BER sensitivity of OFDM systems to carrier frequency offset and wiener phase noise. IEEE Transactions on Communications, 1995, 43(2–4): 191–193
|
5 |
Abdzadeh-Ziabari H, Zhu W P, Swamy M N S. Joint maximum likelihood timing, frequency offset, and doubly selective channel estiamtion for OFDM systems. IEEE Transactions on Vehicular Technology, 2018, 67(3): 2787–2791
|
6 |
Lin D D, Pacheco R A, Lim T J, Hatzinakos D. Joint estimation of channel response, frequency offset, and phase noise in OFDM. IEEE Transactions on Signal Processing, 2006, 54(9): 3542–3554
|
7 |
van de Beek J J, Sandell M, Borjesson P O. ML estimation of time and frequency offset in OFDM systems. IEEE Transactions on Signal Processing, 1997, 45(7): 1800–1805
|
8 |
Schmidl T M, Cox D C. Robust frequency and timing synchronization for OFDM. IEEE Transactions on Communications, 1997, 45(12): 1613–1621
|
9 |
Minn H, Zeng M, Bhargava V K. On timing offset estimation for OFDM systems. IEEE Communications Letters, 2000, 4(7): 242–244
|
10 |
Park B, Cheon H, Kang C, Hong D. A novel timing estimation method for OFDM systems. IEEE Communications Letters, 2003, 7(5): 239–241
|
11 |
Du X, Zhang J, Xu Z, Yu C. A novel timing estimation method for coherent optical OFDM systems. In: Proceedings of Asia Communications and Photonics Conference. Optical Society of America, 2015, paper AS4F. 5
|
12 |
Du X, Zhang J, Li Y, Yu C, Kam P Y. Efficient joint timing and frequency synchronization algorithm for coherent optical OFDM systems. Optics Express, 2016, 24(17): 19969–19977
|
13 |
Cao S, Zhang S, Yu C, Kam P Y. Full-range pilot-assisted frequency offset estimation for OFDM systems. In: Proceedings of Optical Fiber Communication Conference/National Fiber Optic Engineers Conference. Optical Society of America, 2013, paper JW2A. 53
|
14 |
Zhou X, Long K, Li R, Yang X, Zhang Z. A simple and efficient frequency offset estimation algorithm for high-speed coherent optical OFDM systems. Optics Express, 2012, 20(7): 7350–7361
|
15 |
Wu J, Tang M, Xu L, Zhu S, Cheng J, Feng Z, Zhang L, Wang X, Lin R, Deng L, Fu S, Shum P P, Liu D. A robust and efficient frequency offset correction algorithm with experimental verification for coherent optical OFDM system. Journal of Lightwave Technology, 2015, 33(18): 3801–3807
|
16 |
Kim D K, Do S H, Lee H K, Choi H J. Performance evaluations of the frequency detectors for orthogonal frequency division multiplexing. IEEE Transactions on Consumer Electronics, 1997, 43(3): 776–783
|
17 |
Huang Y J, Wei S W. Modified guard band power detection for coarse carrier frequency offset receovery in OFDM system. Wireless Personal Communications, 2008, 45(2): 163–173
|
18 |
Du X, Zhang J, Yu C,Kam P Y. Blind carrier frequency offset estimation for coherent optical OFDM systems. In: Proceedings of Advanced Photonics (IPR, NOMA, Sensors, Networks, SPPCom, SOF). Optical Society of America, 2016, paper SpW2G.3
|
19 |
Zhu P, Li J, Zhao H, Tian Y, Chen Y, Wu Z, Chen Z, He Y. An iterative frequency offset estimation method for coherent optical OFDM system. IEEE Photonics Technology Letters, 2017, 29(11): 877–880
|
20 |
Jignesh J, Corcoran B, Zhu C, Lowery A. Simple optoelectronic frequency-offset estimator for coherent optical OFDM. Optics Express, 2017, 25(25): 32161–32177
|
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