CN109617666B - Feedforward timing method suitable for continuous transmission - Google Patents
Feedforward timing method suitable for continuous transmission Download PDFInfo
- Publication number
- CN109617666B CN109617666B CN201910095046.9A CN201910095046A CN109617666B CN 109617666 B CN109617666 B CN 109617666B CN 201910095046 A CN201910095046 A CN 201910095046A CN 109617666 B CN109617666 B CN 109617666B
- Authority
- CN
- China
- Prior art keywords
- timing
- data
- value
- interpolation filter
- error value
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
- 238000000034 method Methods 0.000 title claims abstract description 22
- 230000005540 biological transmission Effects 0.000 title claims abstract description 13
- 238000005070 sampling Methods 0.000 claims abstract description 20
- 238000001914 filtration Methods 0.000 claims description 16
- 238000004364 calculation method Methods 0.000 claims description 9
- 238000013139 quantization Methods 0.000 claims description 5
- 238000001514 detection method Methods 0.000 claims description 4
- 238000013507 mapping Methods 0.000 claims description 4
- 230000000630 rising effect Effects 0.000 claims description 4
- 238000012545 processing Methods 0.000 abstract description 6
- 238000004891 communication Methods 0.000 abstract description 2
- 238000010586 diagram Methods 0.000 description 6
- 238000013461 design Methods 0.000 description 2
- 230000015556 catabolic process Effects 0.000 description 1
- 238000006731 degradation reaction Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 238000011084 recovery Methods 0.000 description 1
Images
Classifications
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L7/00—Arrangements for synchronising receiver with transmitter
- H04L7/0016—Arrangements for synchronising receiver with transmitter correction of synchronization errors
- H04L7/002—Arrangements for synchronising receiver with transmitter correction of synchronization errors correction by interpolation
- H04L7/0029—Arrangements for synchronising receiver with transmitter correction of synchronization errors correction by interpolation interpolation of received data signal
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L7/00—Arrangements for synchronising receiver with transmitter
- H04L7/0054—Detection of the synchronisation error by features other than the received signal transition
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L7/00—Arrangements for synchronising receiver with transmitter
- H04L7/0079—Receiver details
- H04L7/0087—Preprocessing of received signal for synchronisation, e.g. by code conversion, pulse generation or edge detection
Landscapes
- Engineering & Computer Science (AREA)
- Computer Networks & Wireless Communication (AREA)
- Signal Processing (AREA)
- Synchronisation In Digital Transmission Systems (AREA)
- Digital Transmission Methods That Use Modulated Carrier Waves (AREA)
Abstract
The invention discloses a feedforward timing method suitable for continuous transmission, and belongs to the technical field of signal processing of communication systems. The invention reflects the timing error to the subsequent step by a feedforward mode, interpolates the current sampling value by using an interpolation filter, and obtains approximate optimal sampling points as far as possible so as to achieve the aim of accurate timing synchronization of continuous signals. Compared with a feedback structure for timing synchronization of continuous signals, the feedback structure has the characteristic of simple structure, simplifies the processing flow, and solves the timing problem of continuous transmission while reducing the implementation complexity. The method also has the advantages of stability, reliability, strong portability, easy popularization and the like, and is particularly suitable for timing synchronization of symbols in the continuous transmission process.
Description
Technical Field
The invention relates to the technical field of signal processing, in particular to a feedforward timing method suitable for continuous transmission.
Background
Symbol timing synchronization is a key link for signal demodulation of a receiving end and is an important premise for correct demodulation. Inaccurate timing synchronization can lead to degradation of demodulation performance, and in severe cases, even failure to perform proper demodulation. The accurate timing synchronization can obtain the optimal sampling point of the code element symbol, and a reliable reference is provided for the subsequent demodulation step.
The current timing synchronization method can be mainly divided into a feedback structure and a feedforward structure according to different implementation structures. The feedback structure adopts the related principle of the phase-locked loop, can obtain more accurate timing according to the feedback loop, and has stable work. However, this structure is relatively complex to implement and consumes a long locking time, and thus is not suitable for timing recovery of burst signals, which is generally used for continuous signal timing. Compared with a feedback structure, the feedforward structure is an open-loop structure, does not depend on the design of a feedback loop, can quickly track the phase change of the symbol, and has the advantage of short acquisition time. The feedforward structure can be divided into two methods of directly extracting the optimal sampling point according to the timing error and obtaining the optimal sampling point by interpolation filtering according to the timing error. The feedforward method of performing interpolation filtering to obtain the optimal sampling point is difficult to implement when processing the timing synchronization of continuous signals, and is therefore mostly used for the timing synchronization of burst communication signals.
Disclosure of Invention
The technical problem to be solved by the present invention is to avoid the above disadvantages in the background art, and to provide a feedforward timing method suitable for continuous transmission. The invention reflects the timing error to the subsequent step by a feedforward mode, interpolates the current sampling value by using an interpolation filter, obtains approximate optimal sampling points as far as possible, and solves the timing problem of continuous transmission while reducing the realization complexity. The invention has the characteristics of stable and reliable performance, high timing accuracy and low complexity.
The purpose of the invention is realized as follows:
a feed forward timing method for continuous transmission, comprising the steps of:
(1) the data after the matched filtering of the receiving end passes through a timing error detection module, and a timing error value is obtained through calculation according to the following formula
Wherein, L represents the observation length of each calculation error, N represents the number of sampling points of each symbol, m represents the current m-th observation length, rkIndicating the kth sample point of the data, k is 0,1,2, …, N-1,is represented by rkComplex conjugate of (a), arg (·) denotes the operation of obtaining the phase, e is the base of the natural logarithm, j is the unit of imaginary number;
Will be provided withSending the data to an address mapping module, and obtaining an address value addr required by the coefficient storage module according to the following formula:
wherein INT (-) represents quantizing the parameter into integer, INTtobit (-) represents obtaining binary representation corresponding to the parameter;
(3) will be provided withEach within the rangeCorresponding interpolation filter coefficient C-2、C-1、C0、C1Carry out quantization rounding according toCorresponding addresses addr 'are respectively stored in four ROMs of the coefficient storage module, the addr' being in binary formThe interpolation filter coefficient is obtained according to a Lagrange cubic interpolation filter coefficient calculation formula:
C-2=μ3/6-μ/6,
C-1=-μ3/2+μ2/2+μ,
C0=μ3/2-μ2-μ/2+1,
C1=-μ3/6+μ2/2-μ/3
(4) reading a ROM table value from the coefficient storage module according to the address value addr obtained in the step (2) to obtain four corresponding interpolation filter coefficients;
(5) error value ofSending to a data selection module according to the error valueObtaining a symbol clock; selecting four data r needing interpolation filtering from the buffer at the rising edge of the symbol clockm-1、rm、rm+1、rm+2(ii) a Phase and error value of symbol clockThe relationship of (a) to (b) is as follows:
(6) carrying out interpolation filtering according to the interpolation filter coefficient obtained in the step (4) and the data obtained in the step (5) to obtain an optimal sampling value yn:
The timing synchronization of the continuous signals is completed.
Compared with the background technology, the invention has the following advantages:
1. the invention adopts an interpolation filtering mode, and the timing accuracy is improved compared with the timing of directly selecting sampling points.
2. The invention adopts a design method of feeding forward the timing error, reduces the processing flow with complex feedback structure and shortens the locking time.
3. On the basis of a feed-forward structure, the invention generates the symbol clocks with different phases according to the timing error, and can realize accurate timing of continuous signals.
4. The invention has stable and reliable performance, simple structure, low realization complexity, strong transportability and popularization and application value.
Drawings
Fig. 1 is a schematic diagram of an embodiment of the present invention.
FIG. 2 is a diagram of a distribution of quantized timing error ranges in a timing method according to an embodiment of the present invention.
FIG. 3 is a schematic diagram illustrating a relationship between a symbol clock and interpolation filter data in the timing method according to the embodiment of the present invention.
Detailed Description
Referring to fig. 1 to 3, a feed forward timing method for continuous transmission, which performs accurate symbol timing synchronization on a signal at a signal receiving end. Fig. 1 is a schematic diagram of a principle of feedforward timing synchronization based on interpolation filtering in the method, and as can be seen from fig. 1, the method is simple to implement and low in complexity. Fig. 2 is a diagram of a quantization timing error range distribution in the timing method, and a plurality of parameters such as symbol clocks of different phases and address values of a filter coefficient memory can be obtained according to the range of the quantization timing error. FIG. 3 is a schematic diagram of the relationship between the symbol clock and the interpolation filter data in the timing method, T in FIG. 3iRepresenting a data sampling period; after the symbol clock is obtained according to the timing error and the sampling clock, the data to be filtered can be obtained under the symbol clock.
Specifically, the method comprises the following steps:
(1) the data after the matched filtering of the receiving end passes through a timing error detection module, and a timing error value is obtained through calculation according to the following formula
In the embodiment, the observation length L is set to 1024, the number N of sampling points of each symbol is set to 4, and the continuous signals after matched filtering are segmented and subjected to timing error estimation according to the timing error estimation algorithm in the timing error detection module to obtain a timing error value
(2) Will be the timing error valueQuantized to obtain an error value Will be provided withSending the data to an address mapping module, and obtaining an address value addr required by the coefficient storage module according to the following formula:
wherein INT (-) represents quantizing the parameter into integer, INTtobit (-) represents obtaining binary representation corresponding to the parameter;
the step is based on the timing error value obtained in (1)Obtaining the error value after quantizationAnd according to the error valueMapping the address value addr of a ROM table in a coefficient storage module;
(3) is calculated to obtainEach within the rangeCorresponding interpolation filter coefficient C-2、C-1、C0、C1The interpolation filter coefficient is quantized and rounded and is respectively stored in four storage ROMs of a coefficient storage module, and a storage address addr' is in a binary formThen the integer value range of addr' is (-128, -127, … 126,127, 126, 127); the interpolation filter coefficients can be obtained according to a lagrangian cubic interpolation filter coefficient calculation formula:
the step is to determine the timing error valueThe decimal interval mu is calculated in the range of (2), and then the coefficient C of the interpolation filter is obtained according to the decimal interval mu-2、C-1、C0、C1Then storing the coefficients in four ROM tables respectivelyCorresponding to the address addr';
(4) sending the address value addr into a filter coefficient storage module, and reading a ROM table value according to the address value addr to obtain a corresponding interpolation filter coefficient;
(5) will be the timing error valueSending to a data selection module according to the error valueObtaining a symbol clock; selecting four data r needing interpolation filtering from the buffer at the rising edge of the symbol clockm-1、rm、rm+1、rm+2(ii) a Phase and timing error values of a symbol clockThe relationship of (a) to (b) is as follows:
in this step, the sampling clock and the timing error value are usedObtaining a symbol clock, wherein different timing errors correspond to different phases of the symbol clock; selecting four data r in a data buffer on rising edges of a symbol clockm-1、rm、rm+1、rm+2The data is the data value of the current to-be-interpolated filtering, and the method can ensure that the continuous signals still provide accurate interpolation filtering data values at the switching points of different observation windows;
(6) carrying out interpolation filtering according to the interpolation filter coefficient obtained in the step (4) and the data obtained in the step (5), and obtaining an optimal sampling value y through the following formula calculationn;
At this point, timing synchronization of the continuous signal is completed.
The invention reflects the timing error to the subsequent step by a feedforward mode, interpolates the current sampling value by using an interpolation filter, and obtains approximate optimal sampling points as far as possible so as to achieve the aim of accurate timing synchronization of continuous signals. Compared with a feedback structure for timing synchronization of continuous signals, the feedback structure has the characteristic of simple structure, simplifies the processing flow, and solves the timing problem of continuous transmission while reducing the implementation complexity. The method also has the advantages of stability, reliability, strong portability, easy popularization and the like, and is particularly suitable for timing synchronization of symbols in the continuous transmission process.
Claims (1)
1. A feed forward timing method for continuous transmission, comprising the steps of:
(1) the data after the matched filtering of the receiving end passes through a timing error detection module, and a timing error value is obtained through calculation according to the following formula
Wherein, L represents the observation length of each calculation error, N represents the number of sampling points of each symbol, m represents the current m-th observation length, rkIndicating the kth sample point of the data, k is 0,1,2, …, N-1,is represented by rkComplex conjugate of (a), arg (·) denotes the operation of obtaining the phase, e is the base of the natural logarithm, j is the unit of imaginary number;
Will be provided withSending the data to an address mapping module, and obtaining an address value addr required by the coefficient storage module according to the following formula:
wherein INT (-) represents quantizing the parameter into integer, INTtobit (-) represents obtaining binary representation corresponding to the parameter;
(3) will be provided withEach within the rangeCorresponding interpolation filter coefficient C-2、C-1、C0、C1Carry out quantization rounding according toCorresponding addresses addr 'are respectively stored in four ROMs of the coefficient storage module, the addr' being in binary formThe interpolation filter coefficient is obtained according to a Lagrange cubic interpolation filter coefficient calculation formula:
C-2=μ3/6-μ/6,
C-1=-μ3/2+μ2/2+μ,
C0=μ3/2-μ2-μ/2+1,
C1=-μ3/6+μ2/2-μ/3
(4) reading a ROM table value from the coefficient storage module according to the address value addr obtained in the step (2) to obtain four corresponding interpolation filter coefficients;
(5) error value ofSending to a data selection module according to the error valueObtaining a symbol clock; selecting four data r needing interpolation filtering from the buffer at the rising edge of the symbol clockm-1、rm、rm+1、rm+2(ii) a Phase and error value of symbol clockThe relationship of (a) to (b) is as follows:
(6) carrying out interpolation filtering according to the interpolation filter coefficient obtained in the step (4) and the data obtained in the step (5) to obtain an optimal sampling value yn:
The timing synchronization of the continuous signals is completed.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
CN201910095046.9A CN109617666B (en) | 2019-01-31 | 2019-01-31 | Feedforward timing method suitable for continuous transmission |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
CN201910095046.9A CN109617666B (en) | 2019-01-31 | 2019-01-31 | Feedforward timing method suitable for continuous transmission |
Publications (2)
Publication Number | Publication Date |
---|---|
CN109617666A CN109617666A (en) | 2019-04-12 |
CN109617666B true CN109617666B (en) | 2021-03-23 |
Family
ID=66021627
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
CN201910095046.9A Active CN109617666B (en) | 2019-01-31 | 2019-01-31 | Feedforward timing method suitable for continuous transmission |
Country Status (1)
Country | Link |
---|---|
CN (1) | CN109617666B (en) |
Families Citing this family (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN113162717A (en) * | 2021-04-01 | 2021-07-23 | 上海兆煊微电子有限公司 | Feedforward timing synchronization method and system for burst communication |
CN113507324B (en) * | 2021-06-17 | 2022-07-29 | 西安空间无线电技术研究所 | Feedforward timing recovery method and system suitable for high-speed satellite-borne optical communication |
Citations (10)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2010138199A2 (en) * | 2009-05-29 | 2010-12-02 | Thomson Licensing | Method and apparatus for symbol timing recovery |
CN104125052A (en) * | 2014-07-24 | 2014-10-29 | 清华大学 | Parallel timing synchronization system and method |
CN105245303A (en) * | 2015-08-28 | 2016-01-13 | 北京理工大学 | High-speed burst demodulation synchronization system |
CN106842248A (en) * | 2016-11-23 | 2017-06-13 | 西安电子科技大学昆山创新研究院 | A kind of new method for improving Beidou receiver timing locating speed |
CN106998236A (en) * | 2017-02-07 | 2017-08-01 | 中国人民解放军国防科学技术大学 | A kind of feedback-type symbol timing synchronizing apparatus and method based on filtering interpolation |
CN107104917A (en) * | 2017-04-05 | 2017-08-29 | 杭州电子科技大学 | Parallel processing TDS OFDM time synchronization methods |
CN107528805A (en) * | 2017-09-04 | 2017-12-29 | 中国电子科技集团公司第四十研究所 | A kind of psk signal synchronous method and device suitable for signal analyzer |
CN108471347A (en) * | 2018-02-11 | 2018-08-31 | 杭州电子科技大学 | A kind of parallel time synchronization method based on accurate loop filtering |
CN108964824A (en) * | 2018-07-06 | 2018-12-07 | 中国电子科技集团公司第五十四研究所 | A kind of anti-Doppler frequency displacement synchronous method based on pseudo-random sequence differential encoding |
CN109067494A (en) * | 2018-08-27 | 2018-12-21 | 电子科技大学 | A kind of UAT data-link time synchronization method and device about CPFSK Modulation Types |
Family Cites Families (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US7305056B2 (en) * | 2003-11-18 | 2007-12-04 | Ibiquity Digital Corporation | Coherent tracking for FM in-band on-channel receivers |
-
2019
- 2019-01-31 CN CN201910095046.9A patent/CN109617666B/en active Active
Patent Citations (10)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2010138199A2 (en) * | 2009-05-29 | 2010-12-02 | Thomson Licensing | Method and apparatus for symbol timing recovery |
CN104125052A (en) * | 2014-07-24 | 2014-10-29 | 清华大学 | Parallel timing synchronization system and method |
CN105245303A (en) * | 2015-08-28 | 2016-01-13 | 北京理工大学 | High-speed burst demodulation synchronization system |
CN106842248A (en) * | 2016-11-23 | 2017-06-13 | 西安电子科技大学昆山创新研究院 | A kind of new method for improving Beidou receiver timing locating speed |
CN106998236A (en) * | 2017-02-07 | 2017-08-01 | 中国人民解放军国防科学技术大学 | A kind of feedback-type symbol timing synchronizing apparatus and method based on filtering interpolation |
CN107104917A (en) * | 2017-04-05 | 2017-08-29 | 杭州电子科技大学 | Parallel processing TDS OFDM time synchronization methods |
CN107528805A (en) * | 2017-09-04 | 2017-12-29 | 中国电子科技集团公司第四十研究所 | A kind of psk signal synchronous method and device suitable for signal analyzer |
CN108471347A (en) * | 2018-02-11 | 2018-08-31 | 杭州电子科技大学 | A kind of parallel time synchronization method based on accurate loop filtering |
CN108964824A (en) * | 2018-07-06 | 2018-12-07 | 中国电子科技集团公司第五十四研究所 | A kind of anti-Doppler frequency displacement synchronous method based on pseudo-random sequence differential encoding |
CN109067494A (en) * | 2018-08-27 | 2018-12-21 | 电子科技大学 | A kind of UAT data-link time synchronization method and device about CPFSK Modulation Types |
Non-Patent Citations (2)
Title |
---|
一种基于M2M4算法的QPSK信噪比估计;尚春杰;《无线电工程》;20180930;全文 * |
一种基于前馈定时的OQPSK 解调方法;陈敬乔;《无线电工程》;20180630;全文 * |
Also Published As
Publication number | Publication date |
---|---|
CN109617666A (en) | 2019-04-12 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
CN107769841B (en) | Iterative demodulation method for satellite communication Turbo code under high dynamic and extremely low signal-to-noise ratio | |
US7773325B2 (en) | Timing recovery for data storage channels with buffered sectors | |
CN109617666B (en) | Feedforward timing method suitable for continuous transmission | |
CN102148681B (en) | System and method for realizing iterative timing synchronization of continuous phase modulation signal | |
CN110690931B (en) | Digital signal adaptive code rate estimation method and device based on multi-wavelet-base combination | |
CN109274623B (en) | Implementation method for correcting carrier frequency offset based on large-point FFT (fast Fourier transform) | |
CN111884984B (en) | Fast carrier Doppler frequency shift capturing system | |
CN108063616B (en) | Non-homologous clock data recovery system based on oversampling | |
CN114938255B (en) | High-speed time domain parallel timing synchronization method based on O & M algorithm | |
CN105917624A (en) | Communication apparatus, demodulation apparatus, carrier reproduction apparatus, phase error compensation apparatus, phase error compensation method, and storage medium storing phase error compensation program | |
CN110430153B (en) | Frequency offset correction method and device for satellite communication | |
WO2007092744B1 (en) | Wireless communication unit and method for receiving a wireless signal | |
CN107425853B (en) | FFT-based blind correction method for mismatch error of dual-channel TIADC system | |
JPH05153174A (en) | Method of demodulating and synchronizing digital-modulated signal | |
CN114553652B (en) | Low-complexity multi-modulation-index continuous phase modulation synchronization method | |
CN106059655B (en) | A kind of satellite communication burst time synchronization method | |
CN112291039B (en) | Data coding transmission method based on channel signal period | |
CN110351066A (en) | Clock phase recovery device, method and chip | |
CN104061950A (en) | Method for improving decoding precision of digital decoding system of rotary transformer | |
CN104883329B (en) | The channel estimation and equalization method and apparatus of receiving terminal in satellite communication | |
CN112332817A (en) | Wide-speed high-linearity phase interpolator suitable for 1-28Gbps SerDes | |
CN106789797B (en) | Symbol synchronization method for wireless burst communication PSK signal | |
CN1175581C (en) | Add-compare selection circuit | |
CN101908357B (en) | Correction circuit and method for restoring data | |
CN115189862B (en) | High-precision synchronous data synchronous clock recovery method |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
PB01 | Publication | ||
PB01 | Publication | ||
SE01 | Entry into force of request for substantive examination | ||
SE01 | Entry into force of request for substantive examination | ||
GR01 | Patent grant | ||
GR01 | Patent grant | ||
CB03 | Change of inventor or designer information | ||
CB03 | Change of inventor or designer information |
Inventor after: Chen Jingqiao Inventor after: Kou Chenguang Inventor after: Li Yong Inventor after: Wang Saiyu Inventor after: Shang Chunjie Inventor before: Kou Chenguang Inventor before: Chen Jingqiao Inventor before: Li Yong Inventor before: Wang Saiyu Inventor before: Shang Chunjie |