CN103905362B - The method of estimation and device of carrier wave and sampling frequency deviation in multi-carrier communications systems - Google Patents
The method of estimation and device of carrier wave and sampling frequency deviation in multi-carrier communications systems Download PDFInfo
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Abstract
The present invention relates to a kind of offset estimation device of multi-carrier communications systems, including：One FFT units, are converted to a frequency domain, and produce multiple symbols by a reception signal by a time domain；Conjugate multiplication unit altogether, receives multiple specific subcarriers indexes, and produces multiple correlations multiple values after having continuous two symbols altogether conjugate multiplication according to those specific subcarriers index；One power unit, receives a power value, and the correlation multiple values of the multiple powers of generation after a power exponentiation are carried out to those correlations multiple value；And a computing unit, the correlation multiple values of those powers are received, and estimate a frequency shift (FS) according to this.
Description
Technical field
The invention relates to the frequency offset estimation methods and device of a kind of multi-carrier communications systems, and particularly one kind
It is common to ground digital video broadcast (Digital Video Broadcasting Terrestrial, hereinafter referred to as DVB-T)
With terrestrial integrated numerical digit serviced broadcast (Integrated Services Digital Broadcasting, hereinafter referred to as ISDB-
T) carrier wave of system and the method for estimation of sampling frequency deviation and device.
Background technology
Multi-carrier communications systems, such as OFDM (Orthogonal Frequency
DivisionMultiplexing, hereinafter referred to as OFDM) technology come out for a long time.OFDM technology can be applied to DVB-T systems
System and ISDB-T systems.In general, OFDM technology is very sensitive for frequency shift (FS) (frequency offset).When
Mismatched between oscillator (oscillator) between transmitter (transmitter) and receiver (receiver)
(mismatch) frequency shift (FS) will, be produced.And these skews include carrier frequency shift (carrierfrequency
Offset, abbreviation CFO) and sampling frequency deviation (sampling frequency offset, abbreviation SFO).
Therefore, how estimating carrier frequency skew and sampling frequency deviation, and simultaneously be applied to DVB-T systems and
ISDB-T systems are the main purpose to be reached of the invention.
The content of the invention
The purpose of the present invention is to propose to a kind of carrier frequency shift for being common to DVB-T systems and ISDB-T systems with take
Sample frequency offset estimation methods and relevant apparatus.
The present invention is related to a kind of offset estimation device of multi-carrier communications systems, including：One fast Fourier transform list
Unit, a frequency-region signal is converted to by a reception signal by a time-domain signal, and produces multiple samplings, corresponding to multiple symbols；One
Conjugation multiplication unit, is had altogether according to the corresponding many samplings of continuous two symbols indexed corresponding to multiple specific subcarriers
The multiple values of multiple correlations are produced after conjugate multiplication；One power unit, receives the plurality of correlation multiple values and carries out one according to this and multiply
Power operation produces the multiple values of the correlation of multiple powers；And a computing unit, the correlation multiple values of those powers are received, and
A frequency shift (FS) is estimated according to this.
The present invention is related to a kind of frequency offset estimation methods of multi-carrier communications systems, comprises the following steps：It is right to calculate
Should be in the multiple values of multiple correlations of many samplings corresponding to continuous two symbols of multiple specific subcarriers index；Multiply according to one
Values of powers carries out power to those correlations multiple value and calculates the correlation multiple value for producing multiple powers；And according to those powers
Correlation multiple values estimate a frequency shift (FS).
More preferably understand to have to above-mentioned and other aspect of the invention, preferred embodiment cited below particularly, and coordinate attached
Figure, is described in detail below：
Brief description of the drawings
The depicted OFDM symbol schematic diagrames in DVB-T systems of Fig. 1.
It is two schematic diagrames of the correlation of continuous symbol of calculating that Fig. 2 is depicted.
Fig. 3 show the correlation multiple value schematic diagram of any one CP signal.
Schematic diagram after the depicted multiple value additions for the correlation of all CP signals of Fig. 4.
Schematic diagram after being added up again with the correlation multiple values square of AC signals for all TMCC signals depicted in Fig. 5.
It is that the present invention applies to carrier frequency shift and sampling frequency deviation in multi-carrier communications systems that Fig. 6 is depicted
Estimation unit schematic diagram.
It is that the present invention applies to carrier frequency shift and sampling frequency deviation in multi-carrier communications systems that Fig. 7 is depicted
Method of estimation flow chart.
Main element symbol description
600：Frequency offset estimation device
602：FFT unit
604：Conjugation multiplication unit
606：Power unit
608：Computing unit
S702~S706：Steps flow chart
Specific embodiment
Fig. 1 is refer to, it is OFDM symbols (symbol) schematic diagram in DVB-T systems.OFDM is a kind of multicarrier
Modulation system, its main concept is that data are dispersed into many different frequencies and mutually orthogonal subcarrier (subcarrier),
So that each subcarrier can be used relatively low bit transfer rate to transmit.Lift as a example by a receiving terminal, OFDM modulation is received into letter
Fast Fourier transform (FFT) number is carried out to be changed to frequency domain by time domain (time domain) with by the OFDM modulated received signals
After (frequency domain), its OFDM modulated received signal is conversion multi-sample point as shown in Figure 1, along the same time
Point different sub-carrier constitutes an OFDM symbols, Each point in time tn-1、tn、tn+1Etc. can all receive a symbol (symbol).
In the present embodiment, the OFDM symbols include 19 subcarriers, and it on the frequency axis (f) of Fig. 1 in being represented as -9
~-1,0 ,+1 ~+9 sub-carrier indices (subcarrier index).Wherein, the center frequency point (center of OFDM symbols
Frequency sub-carrier indices (subcarrier index) 0) are set to, toward incremental direction at interval of a fixed frequency
A subcarrier be defined with the sub-carrier indices of a positive number, similarly, toward a son of the direction at interval of the fixed frequency that successively decrease
Carrier wave is also defined with the sub-carrier indices of a negative.
In a DVB-T systems, specification has continuous pilot in arrangement on specific subcarrier in DVB-T specifications
(continual pilot, hereinafter referred to as CP signals), it is the real number of the specific not time-varying occurred in fixed sub-carrier frequencies,
May be used to estimation carrier frequency shift (CFO).From the 1st, CP signal be in the position of sub-carrier indices -5, -2 ,+3 ,+5,
And other positions are then data-signal (data).In DVB-T specifications, also specification CP signal positions are in positive number sub-carrier indices
Number must be same as number of the CP signal positions in negative sub-carrier indices.However, the subcarrier rope where CP signals herein
Draw only one, CP signals can also be arranged at other sub-carrier indices；Additionally, the total number of sub-carriers of each OFDM symbol
It is also not necessarily limited to 19 in the present embodiment.
When carrier frequency shift is produced in DVB-T systems, all of subcarrier can also produce identical sub-carrier frequencies
Skew.As an example it is assumed that the frequency of sub-carrier indices 0 is 500Hz in theory, and carrier frequency shift is 2Hz, then actual
The frequency of sub-carrier indices 0 is 502Hz.And DVB-T systems are to need constantly to estimate carrier frequency shift, and compensate this load
Frequency offset, can just maintain the stabilization of system.
It can be seen from characteristic according to DVB-T systems, due to the real number that CP signals are not time-varying, it does not simultaneously have imaginary part, and
The symbol (sign) of all CP signals is identical.And other data-signals are all while having real part many with imaginary part.Again
Person, the size of the size (magnitude) more than other data-signals of CP signals.Therefore, through the characteristic of CP signals, can be easily
Estimate carrier frequency shift.
ISDB-T systems also have the setting similar to CP signals.Difference is that it is with multiplexing Combining soft control signal
It is (Transmission and Multiplexing Configuration Control, hereinafter referred to as TMCC signals) or auxiliary
Channel signal (Auxiliary Channel, hereinafter referred to as AC signals) is helped to replace CP signals.That is, as the CP in Fig. 1
Signal by TMCC signals or AC signals to replace when, you can be considered as OFDM symbols (symbol) in ISDB-T systems and illustrate
Figure.Certainly, it be actually also by specifications institute specification that the son load of actually TMCC signals and AC signals is indexed.
Compared to CP signals, TMCC signals and AC signals be fixed frequency occur and be loaded with message time-varying reality
Number.In other words, TMCC signals also do not have imaginary part with AC signals, and its symbol is on the occasion of or for negative value sometimes.Furthermore, according to
Size of the size of the specification of ISDB-T specifications, TMCC signals and AC signals more than other data-signals.It is obvious that by
In TMCC signals and the time-varying characteristics of AC signals, system cannot directly with estimate carrier frequency shift, and have extra tune
Necessity of whole calculating.
By taking DVB-T systems as an example, Fig. 2 is refer to, it is two signals of the correlation of continuous symbol of calculating that it is depicted
Figure.Fig. 2 be with each subcarrier in time point tnAnd time point tn+1Two symbols corresponding to two sample points count
Calculate its correlation.Certainly, also can also be using other two continuous symbols, such as time point in those skilled in the art
tn-1And time point tnTwo symbols calculate its correlation.
A conjugate operation is carried out when two correlations of symbol are calculated.Afterwards, it will produce and correspond to 19 subcarrier ropes
The correlation multiple value (Y for drawing-9~Y9).Wherein：
Rn,kAnd RN+1, kRepresent n-th and (n+1)th symbol among output signal in k-th sub-carrier indices it is big
It is small.
Xn,kAnd Xn+1,kRepresent n-th and (n+1)th symbol among data on k-th subcarrier or CP signals
Size.
Hn,kAnd Hn+1,kRepresent n-th and (n+1)th symbol among channel gain on k-th subcarrier
(channel gain)。
(I) under DVB-T systems, carrier frequency shift is Δ f and when not considering sampling frequency deviation：RN, k=HN, k·
XN, k·ej2πΔfn；R* N, k=HN, k·XN, k·e-j2πΔfn；Rn+1,k=HN+1, k·XN+1, kej2πΔf(n+1).Therefore, in identical passage
Gain and in the case of considering noise (N), the correlation multiple values in two symbols in k-th sub-carrier indices are：
Under DVB-T systems, because CP signals are for symbol is identical and size identical real number, and CP signals are only in fixation
There is (k=-5, -2 ,+5, or+5) in frequency.So, the correlation multiple value of the sub-carrier indices corresponding to CP signals can simplify
For：
Yk=| HN, k|2·Xn,k|2·ej2πΔf+N=A·ej2mΔf+N；Wherein, A is an arithmetic number, and k=-5, -2 ,+5 or+
5.As shown in figure 3, it is the correlation multiple value schematic diagram of any one CP signal., it is clear that the angle of the multiple values of this correlation
(2 π Δs f) will be influenceed and cannot determine degree by noise (N).
Embodiments in accordance with the present invention, noise will be may be such that after the correlation multiple value of all CP signals is all added
Repeal by implication, and reduce the influence of noise.Fig. 4 is refer to, after its depicted multiple value addition for the correlation of all CP signals
Schematic diagram., it is clear that after the multiple values of the correlation of all CP signals are added, due to the influence very little of noise.
Therefore, you can estimate carrier frequency shift (Δ f).
In other words, equation (1) as shown below, the angle after the multiple values of the correlation of all of CP signals are added
Degree is divided by 2 π, you can estimate carrier frequency shift (Δ f).
Above-mentioned explanation is directed to DVB-T systems, and the estimating and measuring method of carrier frequency shift is carried out using equation (1).
It is to add up the multiple values of correlation of whole CP signals to obtain carrier frequency shift (Δ f) in above-mentioned explanation.Certainly, lead herein
The technical staff in domain can also add up the correlation multiple value of all CP signals, as long as accumulating the CP signals of enough numbers
Correlation multiple values can carry out the carrier frequency shift (estimation of Δ f).
(II) under DVB-T systems, carrier frequency shift is Δ f and sampling frequency deviation is Δ TsWhen：
Therefore, in identical channel gain and in the case of considering noise (N), the correlation in two symbols in k-th sub-carrier indices
Property multiple values be：
Under DVB-T systems, CP signal positions can be same as CP signal positions in negative in the number of positive number sub-carrier indices
The number of carrier index is identical.So in estimation carrier frequency shift (during Δ f), by the multiple values of the correlation of all of CP signals
It is added, sampling frequency deviation is (Δ Ts) factor be that can almost repeal by implication.Therefore, (Δ f's) estimates carrier frequency shift
Meter is same as equation (1) and repeats no more.
Embodiments in accordance with the present invention, in order to estimating carrier frequency offsets (Δ Ts), it is of the invention by positive number sub-carrier indices
CP signals the correlation multiple value summations CP signals that subtract negative sub-carrier indices the multiple value summations of correlation.In this way,
Be able to will eliminate carrier frequency shift (influence of Δ f), and using this result come estimating carrier frequency offset (Δ Ts).That is,
Above-mentioned explanation is directed to DVB-T systems, and the estimating and measuring method of frequency shift (FS) is sampled using equation (2).Together
Reason, can also utilize the multiple values of the correlation of all CP signals, as long as accumulation is counted enough in those skilled in the art
The correlation multiple value of the correlation multiple value of purpose positive number CP signals and enough the negative CP signals of number can be carried out
Sampling frequency deviation (Δ Ts) estimation.
Furthermore, (1) cannot be utilized with (2) formula come estimating carrier frequency skew (Δ f) and sampling in ISDB-T systems
Frequency shift (FS) (Δ Ts).It is mainly due to, ISDB-T systems are inclined come estimating carrier frequency with AC signals using TMCC signals
Move (Δ f) and sampling frequency deviation (Δ Ts)。
Compared to CP signals, TMCC signals and AC signals are in fixed frequency appearance and the real number of the time-varying for being loaded with message.
In other words, TMCC signals and AC signals be differ be set on the occasion of or negative value real number.Furthermore, according to the rule of ISDB-T specifications
Size of the size of model, TMCC signals and AC signals more than other data-signals.
The present invention is applied in ISDB-T systems, is also to calculate on each subcarrier in time point tnAnd time point tn+1
Two symbols corresponding to two sample points correlation.Certainly, also can also be using others in those skilled in the art
Two continuous symbols, such as time point tn-1And time point tnTwo symbols come carry out calculate its correlation.
After the correlation of two symbols of calculating, it will produce the multiple values of correlation corresponding to all sub-carrier indices.
Wherein：
Rn,kAnd RN+1, kRepresent n-th and (n+1)th symbol among output signal in k-th sub-carrier indices it is big
It is small.
Xn,kAnd Xn+1,kRepresent n-th and (n+1)th symbol among data-signal, TMCC letters on k-th subcarrier
Number or AC signals size.
Hn,kAnd Hn+1,kRepresent n-th and (n+1)th symbol among channel gain on k-th subcarrier.
(III) under ISDB-T systems, carrier frequency shift is (Δ f) and when not considering sampling frequency deviation：RN, k=
HN, k·Xn,k·ej2πΔfn；R* N, k=HN, k·XN, k·e-j2πΔfn；Rn+1,k=HN+1, k·XN+1, k·ej2πΔf(n+1)
In identical channel gain and in the case of considering noise (N), the phase in two symbols in k-th sub-carrier indices
The multiple values of closing property are：
Because the symbol of TMCC signals or AC signals cannot determine.So, the son corresponding to TMCC signals and AC signals
The correlation multiple value of carrier index has following two kinds of situations：
Yk=|Hn,k|2·|XN, k|2·ej2πΔf+N=B·ej2πΔf+N；Or
Yk=-|HN, k|2·|Xn,k 2·ej2πΔf+N=-B·ej2πΔf+N。
Wherein, B is an arithmetic number, and k is the sub-carrier indices of TMCC signals or AC signals.
Produced because above-mentioned correlation multiple value might have two kinds of situations, therefore ISDB-T systems will be unable to such as DVB-
The practice of T systems, directly adds up all TMCC signals and AC signal correlations multiple values and estimates carrier frequency shift.According to this
Inventive embodiments, the present invention first by multiple first square of the values of the correlation of sub-carrier indices after, and confirm its result must be on the occasion of.
That is,：
Yk 2=|Hn,k|4·XN, k|4·ej4πΔf+n=B2·ej4πΔf+n；Wherein n is noise.
Then, add up all TMCC signals it is multiple with the correlation of AC signals be worth square, and estimate carrier frequency according to this
Skew (Δ f).That is,：
That is, in the ISDB-T systems by the multiple values of the correlation of all TMCC signals and AC signals square after, you can
Determine real part be on the occasion of.Then, then after adding up will may be such that noise is repealed by implication, and reduce the influence of noise.Refer to figure
5, the schematic diagram after being added up again with the correlation multiple values square of AC signals for all TMCC signals depicted in it., it is clear that
After the multiple values square of the correlation of all TMCC signals and AC signals and totalling, due to the influence very little of noise n.Cause
This, you can estimate carrier frequency shift (Δ f).
In other words, equation (3) as shown above, by all of TMCC signals and the multiple values of the correlation of AC signals
Angle after square adding up again is divided by 4 π, you can estimate carrier frequency shift (Δ f).
Similarly, above-mentioned explanation carries out the estimating and measuring method of carrier frequency shift for ISDB-T systems.In above-mentioned explanation
It is middle that the correlation multiple values square and totalling of whole TMCC signals and AC signals are obtained into carrier frequency shift (Δ f).However,
Can also be not required to the correlation multiple value square of AC signals add up all of TMCC signals again, as long as accumulating enough numbers
TMCC signals can carry out the carrier frequency shift (estimation of Δ f) with the correlation multiple value of AC signals.
Certainly, the carrier frequency deviation estimating method of above-mentioned ISDB-T systems, can also apply to DVB-T without doubt
System, and estimate its carrier frequency shift.
(IV) under DVB-T systems, while considering carrier frequency shift (Δ f) and sampling frequency deviation (Ts) when：
Therefore, in identical channel gain and in the case of considering noise (N), the correlation in two symbols in k-th sub-carrier indices
Property multiple values be：
The multiple values of correlation square are：
Under ISDB-T systems, TMCC signals can be same as TMCC letters with AC signal positions in the number of positive number sub-carrier indices
It is number identical in the number of negative sub-carrier indices with AC signal positions.Therefore, the correlation of all TMCC signals and AC signals is added up
Multiple value square when, sampling frequency deviation be (Δ Ts) factor can almost repeal by implication.Therefore, carrier frequency shift
(estimation of Δ f) is same as equation (3), repeats no more.
Embodiments in accordance with the present invention, in order to estimating carrier frequency offsets (Δ Ts), it is of the invention by positive number sub-carrier indices
The correlation multiple value summations of TMCC signals and AC signals subtract the TMCC signals of negative sub-carrier indices and the phase of AC signals
The multiple value summations of closing property.In this way, carrier frequency shift (the influence of Δ f), and estimate carrier wave using this result be able to will be eliminated
Frequency shift (FS) (Δ Ts).That is,
Similarly, above-mentioned explanation is the estimating and measuring method that ISDB-T systems are sampled frequency shift (FS).Certainly, equation
(4) can also be not required to use all of TMCC signals and AC signals, as long as accumulating the TMCC signals and AC signals of enough numbers
Correlation multiple values can be sampled frequency shift (FS) (Δ Ts) estimation.
Certainly, the carrier frequency deviation estimating method of above-mentioned ISDB-T systems, can also apply to DVB-T without doubt
System, and estimate its carrier frequency shift.
Fig. 6 is refer to, it is depicted for the present invention applies to carrier frequency shift and sampling in multi-carrier communications systems
The estimation unit schematic diagram of frequency shift (FS).This Frequency offset estimation device 600 includes：One fast Fourier transform (FFT) unit
602nd, conjugation multiplication unit 604, power unit 608, computing unit 608.
First, fundamental frequency signal is carried out fast Fourier transform by FFT unit, and fundamental frequency signal is changed to frequency domain by time domain
Afterwards, multiple symbol (t can sequentially be producedn) input conjugation multiplication unit 604.
Conjugation multiplication unit 604 can be directed to the phase that specific subcarrier index (k) calculates two sample points of every two continuous symbols
The multiple values of closing property.For example, under DVB-T systems, sub-carrier indices of the conjugation multiplication unit 604 for all CP signals
K () produce after conjugation multiplication the correlation multiple values of all CP signals.Or, under ISDB-T systems, it is conjugated multiplication list
Unit 604 for the sub-carrier indices (k) of all TMCC signals and AC signals produce after conjugation multiplication all TMCC signals with
The multiple values of the correlation of AC signals.
Power unit 606 can receive the correlation multiple values of specific subcarrier index, and be entered according to power value (M)
The power of the multiple values of correlation of row specific subcarrier index is calculated.For example, can under ISDB-T or DVB-T systems
The power value (M) of input 2, the correlation multiple value that power unit 606 will can be received carries out the power of quadratic power.Similarly,
Under DVB-T systems, power unit 606 can also receive 1 power value (M), and the correlation multiple value of CP signals is carried out
The power of first power.
Then, computing unit 608 can calculate carrier frequency shift (Δ f) or sampling frequency deviation (Δ Ts).Also
That is, in ISDB-T or DVB-T systems and power value (M) of input 2, computing unit 608 is using equation (3), (4) meter
Calculate carrier frequency shift (Δ f) or sampling frequency deviation (Δ Ts).Or, in DVB-T systems and the power value of input 1
(M) when, computing unit 608 calculates carrier frequency shift (Δ f) or sampling frequency deviation (Δ using equation (1), (2)
Ts)。
Fig. 7 is refer to, it is depicted for the present invention applies to carrier frequency shift and sampling in multi-carrier communications systems
The method of estimation flow chart of frequency shift (FS).
First, the multiple values (step S702) of correlation of specific subcarrier index in continuous two symbols are calculated.Then,
The power that the correlation multiple value of the specific subcarrier index is distinctly carried out according to power value calculates (step S704).Then,
Result after being calculated according to the step power of money one, estimating carrier frequency skew (Δ f) and sampling frequency deviation (Δ Ts)
For example, under DVB-T systems, conjugation multiplication unit 604 receives the sub-carrier indices (k) of all CP signals,
And produce after conjugation multiplication the correlation multiple values of all CP signals.In the case where power value (M) is 1, you can according to
Equation (1), (2) carry out estimating carrier frequency skew (Δ f) and sampling frequency deviation (Δ Ts)。
Or, under ISDB-T systems, conjugation multiplication unit 604 receives the subcarrier rope of all TMCC signals and AC signals
Draw (k), and produce after conjugation multiplication the correlation multiple values of all TMCC signals and AC signals.It is 2 in power value (M)
In the case of, carry out square calculating of correlation multiple value out of the ordinary.Afterwards, you can estimate carrier frequency according to equation (3), (4)
Rate skew (Δ f) and sampling frequency deviation (Δ Ts).Certainly, estimating carrier frequency is inclined during this mode is also applied for DVB-T systems
Move (Δ f) and sampling frequency deviation (Δ Ts)。
In sum, although the present invention is disclosed as above with preferred embodiment, and so it is not limited to the present invention.This hair
Bright those of ordinary skill in the art, without departing from the spirit and scope of the present invention, when various changes can be made
With retouching.Therefore, protection scope of the present invention is worked as to be defined by tbe claims and is defined.
Claims (20)
1. the Frequency offset estimation device of a kind of multi-carrier communications systems, including：
One FFT units, are converted to a frequency-region signal, and produce multiple by a reception signal by a time-domain signal
Sampling, corresponding to multiple symbols；
Conjugate multiplication unit altogether, according to the corresponding the plurality of sampling of continuous two symbols indexed corresponding to multiple specific subcarriers
Multiple correlation multiple values are produced after carrying out conjugate multiplication altogether；
One power unit, receives the plurality of correlation multiple value and carries out the multiple powers of power exponentiation generation according to a power value
The multiple values of correlation；And
One computing unit, receives the correlation multiple value of those powers to estimate a frequency shift (FS), and the wherein estimation is relevant to this
Power value；
Wherein, the frequency shift (FS) device applies to a DVB-T systems, and those specific subcarriers index be it is multiple it is continuous draw show letter
Number sub-carrier indices.
2. Frequency offset estimation device as claimed in claim 1, it is characterised in that the frequency shift (FS) is a carrier frequency shift
Or a sampling frequency deviation.
3. Frequency offset estimation device as claimed in claim 2, it is characterised in that the power unit also receives a power value evidence
To carry out the power exponentiation, the power value is 1, and the computing unit is added up after calculating according to the multiple values of correlation of those powers
The angle estimation carrier frequency shift for obtaining.
4. Frequency offset estimation device as claimed in claim 2, it is characterised in that the power unit also receives a power value evidence
To carry out the power exponentiation, the power value is 1 and those specific subcarriers index includes the positive number subcarrier rope of a Part I
Regard it as and a Part II negative sub-carrier indices, and the computing unit is right by the positive number sub-carrier indices of Part I institute
The correlation multiple value of those powers answered is added up after calculating and obtains a first angle, by the negative subcarrier rope of the Part II
A second angle is obtained after the correlation multiple value totalling calculating for drawing those corresponding powers, and is subtracted according to the first angle
The result of the second angle is gone to estimate the sampling frequency deviation.
5. Frequency offset estimation device as claimed in claim 2, it is characterised in that the power unit also receives a power value evidence
To carry out the power exponentiation, the power value is 2, and the computing unit is added up after calculating according to the multiple values of correlation of those powers
The angle estimation carrier frequency shift for obtaining.
6. Frequency offset estimation device as claimed in claim 2, it is characterised in that the power unit also receives a power value evidence
To carry out the power exponentiation, the power value is 2 and those specific subcarriers index includes the positive number subcarrier rope of a Part I
Regard it as and a Part II negative sub-carrier indices, and the computing unit is right by the positive number sub-carrier indices of Part I institute
The correlation multiple value of those powers answered adds up the first angle obtained after calculating, by the negative subcarrier of the Part II
The multiple values of correlation of those corresponding powers of index add up the second angle obtained after calculating, and according to this first jiao
The result that degree subtracts the second angle estimates the sampling frequency deviation.
7. the Frequency offset estimation device of a kind of multi-carrier communications systems, including：
One FFT units, are converted to a frequency-region signal, and produce multiple by a reception signal by a time-domain signal
Sampling, corresponding to multiple symbols；
Conjugate multiplication unit altogether, according to the corresponding the plurality of sampling of continuous two symbols indexed corresponding to multiple specific subcarriers
Multiple correlation multiple values are produced after carrying out conjugate multiplication altogether；
One power unit, receives the plurality of correlation multiple value and carries out the multiple powers of power exponentiation generation according to a power value
The multiple values of correlation；And
One computing unit, receives the correlation multiple value of those powers to estimate a frequency shift (FS), and the wherein estimation is relevant to this
Power value；
Wherein, the frequency shift (FS) device applies to an ISDB-T systems, and those specific subcarriers index is multiple multiplexing configurations
The sub-carrier indices of control signal and auxiliary channel signal.
8. Frequency offset estimation device as claimed in claim 7, it is characterised in that the frequency shift (FS) is a carrier frequency shift
Or a sampling frequency deviation.
9. Frequency offset estimation device as claimed in claim 8, it is characterised in that the power unit also receives a power value evidence
To carry out the power exponentiation, the power value is 2, and the computing unit is added up after calculating according to the multiple values of correlation of those powers
The angle estimation carrier frequency shift for obtaining.
10. Frequency offset estimation device as claimed in claim 8, it is characterised in that the power unit also receives a power value
The power exponentiation is carried out according to this, and the power value is 2 and those specific subcarriers index includes the positive number subcarrier of a Part I
The negative sub-carrier indices of index and a Part II, and the computing unit is by the positive number sub-carrier indices institute of the Part I
The correlation multiple value of corresponding those powers is added up after calculating and obtains a first angle, by the negative subcarrier of the Part II
The correlation multiple value of those corresponding powers of index is added up after calculating and obtains a second angle, and according to the first angle
The result for subtracting the second angle estimates the sampling frequency deviation.
A kind of 11. frequency offset estimation methods of multi-carrier communications systems, comprise the following steps：
Multiple multiple correlations for sampling that calculating corresponds to corresponding to continuous two symbols of multiple specific subcarriers indexes are more
Individual value；
The correlation multiple values that power calculates the multiple powers of generation are carried out to those correlations multiple value according to a power value；And
Correlation multiple values according to those powers estimate a frequency shift (FS), and the wherein estimation is relevant to the power value；
Wherein, the frequency shift (FS) device applies to a DVB-T systems, and those specific subcarriers index be it is multiple it is continuous draw show letter
Number sub-carrier indices.
12. frequency offset estimation methods as claimed in claim 11, it is characterised in that the frequency shift (FS) is that a carrier frequency is inclined
Move or a sampling frequency deviation.
13. frequency offset estimation methods as claimed in claim 12, it is characterised in that the power value is 1, and estimates the carrier wave
Frequency shift (FS) also comprises the following steps：
The multiple values of correlation according to those powers add up an angle estimation of acquisition carrier frequency shift after calculating.
14. frequency offset estimation methods as claimed in claim 12, it is characterised in that the power value is 1, and those specific sons
Carrier index includes the positive number sub-carrier indices of a Part I and the negative sub-carrier indices of a Part II, and estimates to be somebody's turn to do
Sampling frequency deviation further includes the following steps：
The multiple values of the correlation of those powers corresponding to the positive number sub-carrier indices of the Part I are added up and is obtained after calculating
One first angle；
The multiple values of the correlation of those powers corresponding to the negative sub-carrier indices of the Part II are added up and is obtained after calculating
One second angle；And
The result for subtracting the second angle according to the first angle estimates the sampling frequency deviation.
15. frequency offset estimation methods as claimed in claim 12, it is characterised in that the power value is 2, and estimates the carrier wave
Frequency shift (FS) also comprises the following steps：
The multiple values of correlation according to those powers add up an angle estimation of acquisition carrier frequency shift after calculating.
16. frequency offset estimation methods as claimed in claim 12, it is characterised in that the power value is 2 and those specific sons
Carrier index includes the positive number sub-carrier indices of a Part I and the negative sub-carrier indices of a Part II, and estimates to be somebody's turn to do
Carrier frequency shift also comprises the following steps：
The multiple values of the correlation of those powers corresponding to the positive number sub-carrier indices of the Part I are added up and is obtained after calculating
One first angle；
The multiple values of the correlation of those powers corresponding to the negative sub-carrier indices of the Part II are added up and is obtained after calculating
One second angle；And
The result for subtracting the second angle according to the first angle estimates the sampling frequency deviation.
A kind of 17. frequency offset estimation methods of multi-carrier communications systems, comprise the following steps：
Multiple multiple correlations for sampling that calculating corresponds to corresponding to continuous two symbols of multiple specific subcarriers indexes are more
Individual value；
The correlation multiple values that power calculates the multiple powers of generation are carried out to those correlations multiple value according to a power value；And
Correlation multiple values according to those powers estimate a frequency shift (FS), and the wherein estimation is relevant to the power value；
Wherein, the frequency shift (FS) device applies to an ISDB-T systems, and those specific subcarriers index is multiple multiplexing configurations
The sub-carrier indices of control signal and auxiliary channel signal.
18. frequency offset estimation methods as claimed in claim 17, it is characterised in that the frequency shift (FS) is that a carrier frequency is inclined
Move or a sampling frequency deviation.
19. frequency offset estimation methods as claimed in claim 18, it is characterised in that the power value is 2, and estimates the carrier wave
Frequency shift (FS) further includes the following steps：
The multiple values of correlation according to those powers add up an angle estimation of acquisition carrier frequency shift after calculating.
20. frequency offset estimation methods as claimed in claim 18, it is characterised in that the power value is 2 and those specific sons
Carrier index includes the positive number sub-carrier indices of a Part I and the negative sub-carrier indices of a Part II, and estimates to be somebody's turn to do
Sampling frequency deviation also comprises the following steps：
The multiple values of the correlation of those powers corresponding to the positive number sub-carrier indices of the Part I are added up and is obtained after calculating
One first angle；
The multiple values of the correlation of those powers corresponding to the negative sub-carrier indices of the Part II are added up and is obtained after calculating
One second angle；And
The result for subtracting the second angle according to the first angle estimates the sampling frequency deviation.
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| CN101437005A (en) * | 2008-12-12 | 2009-05-20 | 中国人民解放军理工大学通信工程学院 | Method for estimating integer multiple frequency deviation with timing error during communication synchronization process |
| CN101753499A (en) * | 2008-12-05 | 2010-06-23 | 三星电子株式会社 | Method for jointly estimating the integral multiple carrier frequency shift and accurate symbol timing |
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| CN101911628A (en) * | 2008-01-04 | 2010-12-08 | 高通股份有限公司 | Methods and apparatus for synchronization and detection in wireless communication systems |
| CN101753499A (en) * | 2008-12-05 | 2010-06-23 | 三星电子株式会社 | Method for jointly estimating the integral multiple carrier frequency shift and accurate symbol timing |
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