CN110061943A - A kind of symbol timing synchronization method in mpsk signal demodulation - Google Patents
A kind of symbol timing synchronization method in mpsk signal demodulation Download PDFInfo
- Publication number
- CN110061943A CN110061943A CN201810046706.XA CN201810046706A CN110061943A CN 110061943 A CN110061943 A CN 110061943A CN 201810046706 A CN201810046706 A CN 201810046706A CN 110061943 A CN110061943 A CN 110061943A
- Authority
- CN
- China
- Prior art keywords
- interpolation
- filter
- timing synchronization
- formula
- interpolation filter
- 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.)
- Pending
Links
Classifications
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L27/00—Modulated-carrier systems
- H04L27/0014—Carrier regulation
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L27/00—Modulated-carrier systems
- H04L27/26—Systems using multi-frequency codes
- H04L27/2601—Multicarrier modulation systems
- H04L27/2647—Arrangements specific to the receiver only
- H04L27/2655—Synchronisation arrangements
- H04L27/2662—Symbol synchronisation
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L27/00—Modulated-carrier systems
- H04L27/0014—Carrier regulation
- H04L2027/0024—Carrier regulation at the receiver end
- H04L2027/0026—Correction of carrier offset
Abstract
Symbol timing synchronization method in a kind of demodulation of mpsk signal, belongs to digital communication signal process field.It is characterized in that by extracting symbol rate deviation and feedback control interpolated positions to reach Timing Synchronization.The Gardner synchronized algorithm independently of carrier wave frequency deviation can be used in the extraction of symbol rate deviation, interpolation algorithm uses improved fundamental polynoml interpolation method, this method can export in filter and carry out optimization to the parameter of filter on extreme point, and this method has more accurate synchronization accuracy than interpolation filters such as a cube interpolation, parabolas.
Description
Technical field
It is in the digital communication system of main communication mode that application background of the present invention, which is with mpsk signal,.Summary of the invention is related to
Communications system demodulation end timing synchronization technology, its object is to reduce communication system receiver timing synchronization error,
Timing synchronization performance is improved, convenient for the rational design and performance boost of digital communication system demodulating end.
Background technique
In cooperation digital communication, since the clock crystal oscillator of transmitter and receiver can all generate drift, so that receiving letter
Number clock there are certain symbol rate deviations, the optimal judgement point of symbol drifts about when this deviation will lead to demodulation, from
And influence demodulating end receiver demodulation performance.In non-cooperating digital communication, symbol rate be for receiving end it is unknown, then need
Estimate symbol rate using correlation estimation algorithm from the data received, due to algorithm for estimating precision by algorithm complexity
Limitation, leading to the symbol rate estimated, there are certain deviations.If Timing Synchronization loop energy correction symbol rate deviation, so that it may drop
The low influence due to symbol rate deviation to demodulation performance.
Currently, timing synchronization algorithm mainly has WDM algorithm, M&M algorithm and Gardner in digital communication systems
Algorithm.Wherein WDM algorithm requires quasi- baseband signal to have biggish sample rate, that is, needs a large amount of sampled point, although algorithm has
Higher Timing Synchronization precision but algorithm complexity are high and computationally intensive；M&M algorithm only needs one on each symbol of baseband signal
A sampled point needs directly to adjudicate, and algorithm complexity is lower, but it adjudicates precision to carrier deviation and symbol rate deviation dependence
It is very big；Gardner algorithm only needs two sampled points to each symbol, and algorithm complexity is low and Timing Synchronization precision is not by carrier frequency
The influence of deviation, Gardner algorithm are of considerable interest in timing synchronization.
Since the precision of Gardner algorithm will receive the influence of loop filter bandwidth and loop self noise, how to reduce
The influence of loop filtering bandwidth and self noise is a urgent problem to be solved in current Gardner simultaneous techniques.
Summary of the invention
In order to reduce the signal errors after synchronizing, the precision of timing synchronization is promoted, the present invention provides a kind of MPSK
Time synchronization method in signal demodulation.This method is on the basis of classical Gardner synchronized algorithm, using improved Quito
Formula interpolation filter optimizes the amplitude response of interpolation filter from extreme point, it is intended to it is fixed to obtain optimal symbol
When synchronization accuracy, specifically includes the following steps:
Step 1: selection interpolation knot number, constructs fundamental polynoml interpolation according to baseband signal samples frequency and sample point
The time-domain pulse response of filter；
Step 2: the order and expression formula of polynomial basis function are obtained, according to linear phase number according to interpolation knot number
The symmetry of word interpolation filter designs the controllable parameter function of interpolation filter；
Step 3: appropriately designed filter parameter functionc n(i), according to the optimal extreme point of following duty Optimization,
It can get optimal base polynomial interopolation filter factor.
Preferably, it after obtaining fundamental polynoml optimum filter parameter, is tied according to the Farrow of linear-phase filter
Structure and impulse response can be designed the interpolation filter structure in time synchronization method.And the value after filtering interpolation is calculated, it counts
Formula are as follows:
In formula:mSubject to baseband signal samples basic point,T s Subject to the baseband signal samples period,h() is interpolation filter time domain arteries and veins
Punching response,lenFor the quasi- baseband signal length of number,T i For the interpolation period.Interpolation filter time-domain pulse response is expressed in above formula
Formula are as follows:
In formula:NFor interpolation knot number,LFor filter basic function order,iInterpolation nodes.It is most preferably inserted to acquire filter interpolation
Value coefficient can construct following optimization problem:
In formulaXFor interpolation filter frequency bandwidth (width i.e. between passband and stopband),H(f) be interpolation filter frequency domain
Response,W(f) be weight coefficient function frequency domain response,D(f) be ideal interpolation filter expected response.
Preferably, after obtaining optimal interpolation filter point, interpolation can be calculated using classics Gardner synchronized algorithm and missed
Difference obtains loop filtering as a result, calculating the operation such as new interpolation point position.The present invention is include at least the following beneficial effects: being had
More accurate filtered difference precision, more accurate Timing Synchronization precision.
Detailed description of the invention
Fig. 1 is entire block diagram of the present invention；
Fig. 2 is fundamental polynoml interpolation algorithm operating process schematic diagram of the present invention
Fig. 3 is fundamental polynoml interpolation filter Farrow structural schematic diagram of the present invention
Fig. 4 is optimal judgement result of the bpsk signal after classical Gardner sign synchronization algorithm interpolation
Fig. 5 is optimal judgement result of the bpsk signal of the present invention under symbol timing synchronization method of the present invention
Specific implementation method
In attached drawing, same section is adopted in different views and is indicated by the same numeral, and described various elements
It is not necessarily to scale, present invention will be further explained below with reference to the attached drawings and examples, to enable those skilled in the art join
Book text can be implemented accordingly as directed.
Fig. 1 describes the symbol timing synchronization method in a kind of demodulation of mpsk signal.Base band subject to this method process object
Signal.Quasi- baseband signal pass through respectively interpolation, timing error calculating, loop filtering, numerical control oscillation and etc., export Timing Synchronization
Quasi- baseband signal.
Fig. 2 is fundamental polynoml interpolation algorithm operating process schematic diagram of the present invention.If baseband signal samples rateT s =T/q,T
For character rate,qFor a small integer.According to interpolation knot numberN(generally taking 4), interpolation polynomial orderLObtain polynomial basis letter
Numberf n (k) expression formula:
According to polynomial basis functionf n , interpolation knot numberN、Controllable filter parameter functionc n (i), obtain quasi- interpolation
The time-domain pulse response of filter may be expressed as:
Basic function in above formulaf n With interpolation knot numberNIndependently of each other.It is responded by filter time domainh(k) and baseband signal sample pointx
(mT s ), filtered interpolation point can be obtained are as follows:
In formulamIt is quasi- baseband signal samples basic point,lenIt is quasi- baseband signal sequence length,T i It is the interpolation period.
Fig. 3 is that improved fundamental polynoml interpolation filter Farrow structure is intended to, and improved fundamental polynoml interpolation method is to be based on
The higher interpolation algorithm of a kind of precision of combined symbol timing synchronization errors on the basis of polynomial interopolation.It can give filtering interpolation
Different passband and stopband is arranged in device.Farrow structure interpolation filter designs according to the following steps:
Step 1: set the frequency response of interpolation filter asH(f), in order to make interpolation filter close to ideal characterisitics, fit
Work as design parameterc n (i) filter is made to export optimal extreme point, obtain optimization problem:
In formulaXFor interpolation filter frequency bandwidth (width i.e. between passband and stopband),W(f) it is weight coefficient function,D(f)
It is the expected response of ideal interpolation filter, generally uses 4 kinds of basic function (i.e. basic function ordersLValue 3) it is achieved with well
Interpolation.
Step 2: can be obtained by optimization fundamental polynoml and inserted using Quadratic Programming Solution for the optimization problem in step 1
The coefficient of value filterc n (i)。
Step 3: when obtaining optimal filter coefficients in step 2c n (i) after, fundamental polynoml filtering is realized using Farrow structure
Device.UsingN=4,L=34 polynomial interopolation of base then at most needs 3 multipliers and 12 adders with the realization of Farrow structure
(such as Fig. 3).
The lower simulating, verifying of the implementation complexity of fundamental polynoml interpolation method show that this interpolation method can be into as seen from Figure 3
One step improves interpolation precision, accelerates Timing Synchronization convergence rate, improves Timing Synchronization performance.
It can be seen that by Fig. 4 and Fig. 5, by taking the quasi- baseband signal of BPSK (bipolarity non-return to zero code) as an example, symbol of the invention is fixed
When synchronized algorithm timing accuracy be higher than classical Gardner synchronized algorithm.And the mentioned method of the present invention be also suitable for QPSK,
The Timing Synchronization of the blind demodulation of the quasi- baseband signal such as 8PSK.
Claims (4)
1. the symbol timing synchronization method in a kind of mpsk signal demodulation, which is characterized in that in classical Gardner Symbol Timing base
On plinth, MPSK quasi- baseband signal Timing Synchronization technique center interpolation filter is improved, comprising the following steps: step
One, interpolation knot number is selected, according to baseband signal samples frequency and the time domain of sample point building fundamental polynoml interpolation filter
Impulse response；Step 2: the order and expression formula of polynomial basis function are obtained, according to linear phase according to interpolation knot number
Interpolator has symmetry, designs the controllable parameter function of interpolation filter；Step 3: from filter parameter
Function optimizes on extreme point, obtains optimization problem, and solve it, can get optimal base polynomial interopolation filtering system
Number.
2. a kind of as described in claim 1, the symbol timing synchronization method in mpsk signal demodulation, which is characterized in that work as acquisition
After fundamental polynoml optimum filter parameter, according to the Farrow structure and time-domain pulse response of linear-phase filter, it can set
The structure of the interpolation filter in time synchronization method is counted out, and calculates the value after filtering interpolation, calculating formula are as follows:
In formula:mSubject to baseband signal samples basic point,T s Subject to the baseband signal samples period,h() is interpolation filter time domain impulse
Response,lenFor the quasi- baseband signal length of number,T i For the interpolation period, interpolation filter time-domain pulse response expression formula in above formula
Are as follows:
In formula:NFor interpolation knot number,LFor filter basic function order,iInterpolation nodes are most preferably inserted to acquire filter interpolation
Value coefficient can construct following optimization problem:
In formulaXFor interpolation filter frequency bandwidth (width i.e. between passband and stopband),H(f) be interpolation filter frequency domain
Response,W(f) be weight coefficient function frequency domain response,D(f) be ideal interpolation filter expected response.
3. as described in claim 1 and claim 2, a kind of symbol timing synchronization method in mpsk signal demodulation, feature
It is, after obtaining optimal interpolation filter point, interpolation error can be calculated using classics Gardner synchronized algorithm, obtain loop filter
Wave is as a result, calculate the operation such as new interpolation point position.
4. a kind of timing synchronization using described in 1 ~ 3 any one of right suitable for mpsk signal demodulation.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201810046706.XA CN110061943A (en) | 2018-01-18 | 2018-01-18 | A kind of symbol timing synchronization method in mpsk signal demodulation |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201810046706.XA CN110061943A (en) | 2018-01-18 | 2018-01-18 | A kind of symbol timing synchronization method in mpsk signal demodulation |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN110061943A true CN110061943A (en) | 2019-07-26 |
Family
ID=67314900
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201810046706.XA Pending CN110061943A (en) | 2018-01-18 | 2018-01-18 | A kind of symbol timing synchronization method in mpsk signal demodulation |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN110061943A (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111212007A (en) * | 2020-04-20 | 2020-05-29 | 成都新动力软件有限公司 | Universal 600Mbps intermediate-speed demodulator implementation method and modem |
| CN111245544A (en) * | 2020-01-08 | 2020-06-05 | 西安电子科技大学 | Timing synchronization improvement method for symbol rate deviation in non-cooperative communication system |
| CN114978825A (en) * | 2022-03-23 | 2022-08-30 | 北京交通大学 | Timing synchronization system and method for backscattering communication symbols |
-
2018
- 2018-01-18 CN CN201810046706.XA patent/CN110061943A/en active Pending
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111245544A (en) * | 2020-01-08 | 2020-06-05 | 西安电子科技大学 | Timing synchronization improvement method for symbol rate deviation in non-cooperative communication system |
| CN111212007A (en) * | 2020-04-20 | 2020-05-29 | 成都新动力软件有限公司 | Universal 600Mbps intermediate-speed demodulator implementation method and modem |
| CN114978825A (en) * | 2022-03-23 | 2022-08-30 | 北京交通大学 | Timing synchronization system and method for backscattering communication symbols |
| CN114978825B (en) * | 2022-03-23 | 2023-09-22 | 北京交通大学 | System and method for synchronizing backscattering communication symbol timing |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US8724757B2 (en) | Symbol timing synchronization methods and apparatus | |
| CN102170414B (en) | Demodulation and timing synchronization combined method for GFSK (Gauss Frequency Shift Key) | |
| CN110061943A (en) | A kind of symbol timing synchronization method in mpsk signal demodulation | |
| CN110912847B (en) | GMSK signal demodulation method | |
| CN102064900B (en) | Clock synchronization method and device | |
| CN107483380A (en) | A kind of OQPSK signal high-frequency offset carrier synchronous method based on multistage architecture | |
| CN109361634A (en) | The compensation method and system of receiver carrier wave frequency deviation | |
| CN109462421A (en) | Signal timing recovery method and recovery device, signal demodulating method and demodulating system | |
| Spalvieri et al. | Wiener's analysis of the discrete-time phase-locked loop with loop delay | |
| CN107948111B (en) | Sampling frequency offset correction method of OFDM system | |
| CN108768909B (en) | 2FSK symbol synchronization method and system based on minimum variance | |
| CN106789797B (en) | Symbol synchronization method for wireless burst communication PSK signal | |
| CN109756206A (en) | Interpolation filter construction method and system | |
| CN114465691A (en) | Low-complexity constant envelope phase modulation signal sampling deviation estimation and compensation method and system | |
| Pelet et al. | Timing jitter analysis of optimum non-data-aided symbol synchronizer for QAM | |
| Tuukkanen et al. | Combined interpolation and maximum likelihood symbol timing recovery in digital receivers | |
| US20060248133A1 (en) | Modified transposed farrow structure | |
| US20040047463A1 (en) | Robust symbol timing recovery circuit for telephone line modem | |
| Zhang et al. | A modified timing synchronization algorithm for QPSK in digital receiver | |
| US20180091352A1 (en) | Symbol synchronization method and apparatus | |
| Wu et al. | Low-complexity feedforward symbol timing estimator using conditional maximum-likelihood principle | |
| CN104618288B (en) | The symbol timing synchronization method and device of a kind of radio communication detecting system | |
| Zhu et al. | A fully digital timing recovery scheme using two samples per symbol | |
| Zhong et al. | Symbol timing estimation with multi-h CPM signals | |
| CN113162713B (en) | Variable symbol rate timing recovery method and system based on Gardner algorithm |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| WD01 | Invention patent application deemed withdrawn after publication |
Application publication date: 20190726 |
|
| WD01 | Invention patent application deemed withdrawn after publication |