Journal of Jilin University(Engineering and Technology Edition) ›› 2022, Vol. 52 ›› Issue (11): 2728-2734.doi: 10.13229/j.cnki.jdxbgxb20210352

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A new algorithm for OFDM timing synchronization and hardware implementation optimization

Lei PAN1,2,3(),Lan CHEN1,Sheng-li ZHU4,Wen-yan TONG5   

  1. 1.Institute of Microelectronics，Chinese Academy of Sciences，Beijing 100029，China
    2.University of the Chinese Academy of Sciences，Beijing 100039，China
    3.Beijing Key Laboratory of Three Dimensional and Nanometer Integrated Circuit Design Automation Technology，Beijing 100029，China
    4.Beijing Ikingtec Intelligent Technology Co. ，Ltd. ，Beijing 100007，China
    5.Liaoning Industry and Trade School，Shenyang 110122，China
  • Received:2021-04-22 Online:2022-11-01 Published:2022-11-16

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Abstract:

This article introduces an algorithm for orthogonal frequency divisition multiplexing（OFDM） timing synchronization—correlated peak slope detection algorithm. In a multipath channel environment， due to multipath reflection， the front part of the cyclic prefix that OFDM complies with will be affected by Inter Symbol Interference（ISI）. This paper innovatively proposes a time-domain timing synchronization algorithm. The algorithm determines the arrival position of the last path by detecting the slope of the correlation peak， and estimates the dispersion length of the multipath channel， so that the subsequent fast Fourier transform（FFT） window position avoids the ISI， and provides a reference value for the selection of filter coefficients for channel estimation. This algorithm is also very suitable for application in multipath channels with equal strength and two paths. Finally， the algorithm was simulated with MATLAB and compared with the classic algorithm， which proved that the algorithm can better avoid ISI in the case of low signal-to-noise ratio. In addition， for a low-cost IoT communication system similar to NB-IOT that uses OFDM technology， this article simplifies the algorithm， which can reduce the cost of implementing the baseband chip of the IoT terminal and reduce the cost of the terminal.

Key words: orthogonal frequency divisition multiplexing（OFDM）, timing synchronization, correlated peak slope, digital IC design optimization, base band ASIC

CLC Number: 

  • TN929.5

Fig.1

Influence of multipath channel on OFDM symbol on time axis"

Fig.2

Beacon composed of PN sequence"

Fig.3

Ideal correlation peak under the condition of equal-strength two-path channel with no noise and no Doppler frequency offset"

Fig.4

Transmission data structure for simulation"

Table 1

TU channel model"

路径序号时延/μs增益/dB
10-3
20.20
30.5-2
41.6-6
52.3-8
65.0-10

Fig.5

Comparison of timing probability statistics under TU channel"

Table 1

CT-8 channel model"

路径序号时延/μs增益/dB
10-18
21.80
32.0-20
43.6-20
57.5-10
631.80

Fig.6

Comparison of timing probability statistics under CT-8 channel"

Table 3

Random channel model constraints"

随机信道条件数值
信噪比（SNR）/dB10
多径数/径1~10
延时的随机范围/μs0~30
增益的随机范围/dB0~-20

Fig.7

Random channel timing position statistics"

Table 4

Non-last path timing windowing energy loss statistics under random channel model"

早于最后一径的采样点数损失能量百分比/%
32.3915
273.1014
1041.7351

Fig.8

Random channel timing position statistics of S.C.A algorithm"

1 刘发伟. 无线通信调制—OFDM技术研究[J]. 中国新通信,2018, 20(7): 33.
Liu Fa-wei. Wireless communication modulation-OFDM technology research[J]. China New Telecommunication, 2018, 20(7): 33.
2 周平, 周思远, 刘思含, 等. 基于Zadoff-Chu序列的OFDM精确定时同步算法[J]. 信息技术, 2019,43(1): 1-4.
Zhou Ping, Zhou Si-yuan, Liu Si-han, et al. Accurate timing synchronization algorithm based on zadoff-chu sequence for OFDM system[J]. Information Technology, 2019, 43(1): 1-4.
3 何裕舒, 郭浩, 张阳. 基于训练序列的SC-FDE系统定时同步改进算法[J]. 现代电子技术, 2018, 41(2): 14-16.
He Yu-shu, Guo Hao, Zhang Yang. Improved timing synchronization algorithm for SC-FDE system based on training sequence[J]. Modern Electronics Technique, 2018, 41(2): 14-16.
4 杨建平, 李路, 郭强胜. 基于训练序列的OFDM系统定时同步设计与实现[J]. 通信技术, 2018, 51(10): 2314-2316.
Yang Jian-ping, Li Lu, Guo Qiang-sheng. Design and implementation of OFDM timing synchronization based on training sequence[J]. Communications Technology, 2018, 51(10): 2314-2316.
5 王思拨, 马社祥, 孟鑫, 等. 基于训练序列的OFDM频率同步改进算法[J]. 电子技术应用, 2017, 43(3): 104-107.
Wang Si-bo, Ma She-xiang, Meng Xin, et al. Improved frequency synchronization method for OFDM systems based on training sequence[J]. Application of Electronic Technique, 2017, 43(3): 104-107.
6 孙浩然. 相干光OFDM系统同步算法及信道估计算法的研究[D]. 深圳: 哈尔滨工业大学深圳研究生院,2016.
Sun Hao-ran. Research on the synchronization algorithm and channel estimation algorithm of coherent optical orthogonal frequency division multiplexing system[D]. Shenzhen: Graduate School of Shenzhen, Harbin Institute of Technology, 2016.
7 吴奔, 陈西宏, 刘晓鹏, 等. 散射通信中OFDM/OQAM的ICI和ISI分析[J]. 火力与指挥控制, 2015, 40(9): 35-39, 44.
Wu Ben, Chen Xi-hong, Liu Xiao-peng, et al. Analysis of ICI and ISI in troposcatter communication based on OFDM /OQAM modulation[J]. Fire Control & Command Control, 2015, 40(9), 35-39, 44.
8 任凯旋. 相干光OFDM系统中定时同步和载波频偏估计算法的研究[D]. 武汉: 中国地质大学(武汉)机械与电子信息学院, 2018.
Ren Kai-xuan. Research on the timing synchronization and carrier frequency offset estimation algorithm for CO-OFDM system[D]. Wuhan: School of Mechanical Engineering and Electronic Information, China University of Geosciences(Wuhan), 2018.
9 王丽华. 基于CAZAC序列的OFDM同步符号设计[D]. 西安: 西安电子科技大学通信工程学院, 2014.
Wang Li-hua. Premable design for OFDM system based on CAZAC sequence[D]. Xi'an: School of Telecommunications Engineering, XIDIAN University, 2014.
10 张秀艳,刘珈池.基于ZC序列的OFDM系统定时同步改进算法[J]. 吉林大学学报:信息科学版, 2019, 37(6): 610-616.
Zhang Xiu-yan, Liu Jia-chi. Improved timing synchronization algorithm for OFDM system based on ZC sequence[J]. Journal of Jilin University(Information Science Edition), 2019, 37(6): 611-616.
11 陈颖, 聂伟. OFDM系统改进的训练序列结构及时频同步算法[J]. 电子技术应用, 2019, 45(6): 89-92, 96.
Chen Ying, Nie Wei. Improved training sequence structure and timing and frequency synchronization algorithm for OFDM system[J]. Application of Electronic Technique, 2019, 45(6): 89-92, 96.
12 国家广播电影电视总局. . 移动多媒体广播第1部分: 广播信道帧结构、信道编码和调制 [S].
13 3GPP. 3GPP TS 38.211 V15.7.0. Technical specification group radio access network: physical channels and modulation(Release 15) [S].
14 Minn H, Zeng M, Bhargava V K. On timing offset estimation for OFDM systems[J]. IEEE Communications Letters, 2000, 4(7): 242-244.
15 Schmidl T M, Cox D C. Low-overhead, low-complexity [Burst] synchronization for OFDM[C]//IEEE International Conference on Communications, Dallas, USA, 1996: 1301-1306.
16 Schmidl T M, Cox D C. Robust frequency and timing synchronization for OFDM[J]. IEEE Transactions on Communications, 1997, 45(12): 1613-1621.
17 Awoseyila B, Kasparis C, Evans B G. Robust time-domain timing and frequency synchronization for OFDM systems[J]. IEEE Trans Consum Electron, 2009, 55(2): 391-399.
18 刘毅, 李丹萍, 胡梅霞, 等. 低信噪比下MIMO-OFDM系统时频同步方案[J]. 吉林大学学报: 工学版, 2008, 38(2): 250-254.
Liu Yi, Li Dan-ping, Hu Mei-xia, et al. Synchronization for MIMO-OFDM system in low SNR enviroments[J]. Journal of Jilin University(Engineering and Technology Edition), 2008, 38(2): 250-254.
19 王弋妹.DTMB系统基带处理算法与实现[D].天津:天津大学电子信息工程学院, 2009.
Wang Yi-mei, The Implementation of baseband processing algorithm of DTMB system[D]. Tianjin: School of Electronic Information Engineering, Tianjin University, 2009.
20 You X D, Chen J, Yu C Y, et al. Time domain reshuffling for OFDM based indoor visible light communications[J]. Optics Express, 2017, 25(10): 11606-11621.
21 许炜阳,周杰,王雨晴,等.基于信道估计的OFDM定时同步算法[J]. 吉林大学学报: 工学版, 2016, 46(1): 290-295.
Xu Wei-yang, Zhou Jie, Wang Yu-qing, et al. OFDM timing synchronization algorithm based on channel estimation[J]. Journal of Jilin University(Engineering and Technology Edition), 2016, 46(1): 290-295.
[1] XU Wei-yang, ZHOU Jie, WANG Yu-qing, WU Yu-cheng. OFDM timing synchronization algorithm based on channel estimation [J]. 吉林大学学报(工学版), 2016, 46(1): 290-295.
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