CN102075460A - Frequency offset estimating method and device based on data - Google Patents

Abstract

The invention discloses a frequency offset estimating method based on data, which comprises the steps of: obtaining a pilot frequency bit frequency-domain channel estimation value of a target user; obtaining phase information caused by the frequency offset according to the pilot frequency bit frequency-domain channel estimation value; obtaining phase difference among different OFDM (Orthogonal Frequency Division Multiplexing) symbol data or data on different subcarriers of an OFDM symbol according to the phase information; and obtaining a frequency offset value according to the phase difference. The invention also discloses a frequency offset estimation device based on the data. According to the invention, the performance frequency offset estimation capacity of a receiving machine can be improved, the relative frequency offset between a base station and a terminal is effectively estimated, the interference caused by the orthogonal damage on the subcarriers by an OFDM system is reduced, the estimation and compensation range of the frequency offset for the receiving machine is improved, especially when a large frequency offset exists in a high-speed mobile environment link, the frequency offset value existing the system can be more accurately estimated, and the reliable guarantee is provided for the communication service quality.

Description

A kind of frequency deviation estimating method and device based on data

Technical field

The present invention relates to wireless communication technology field, particularly relate to a kind of frequency deviation estimating method and device based on data.

Background technology

LTE (Long Term Evolution, Long Term Evolution) project is 3GPP (Third Generation Partnership Projects over the past two years, third generation partnership project) the new technology development project of the maximum of Qi Donging, it improves and has strengthened the aerial access technology of 3G (Third Generation, 3G (Third Generation) Moblie technology).Compare with 3G, LTE has more technical advantage, is embodied in higher user data rate, grouping transmission, the improvement that reduces system delay, power system capacity and covering and the aspects such as reduction of operation cost.

The LTE down link adopts OFDM (Orthogonal Furequency Division Multiplexity, OFDM) technology, OFDM has characteristics such as availability of frequency spectrum height, anti-multipath interference, and ofdm system can be resisted the influence that wireless channel brings effectively.LTE ul transmissions scheme adopts SC-FDMA (the Single Carrier Furequency Division Multiplexity of band Cyclic Prefix, single carrier frequency division is multiplexing), in the SC-FDMA transmission plan of up employing band Cyclic Prefix, use DFT (DiscreteFourier Transformation, discrete Fourier transform (DFT)) obtains frequency-region signal, insert nil symbol then and carry out frequency spectrum shift, signal after moving is again by IFFT (Inverse Fast Fourier Transformation, contrary fast fourier transform), can reduce the peak-to-average power ratio of launch terminal.

For multicarrier system, the skew of carrier frequency can cause producing between the subchannel to be disturbed.Have a plurality of orthogonal sub-carriers in the ofdm system, output signal is the stack of a plurality of sub-channel signals, because subchannel covers mutually, this just has higher requirement to the orthogonality of intercarrier.

Because moving of terminal can produce Doppler frequency shift between base station and terminal, in mobile communication system, particularly under the high speed scene, this frequency displacement is especially obvious.Doppler frequency shift will make and produce frequency error between the Receiver And Transmitter, cause received signal to be offset in frequency domain, introduce inter-carrier interference, make the bit error rate performance of system worsen.

The size of Doppler frequency shift is relevant with the speed of related movement size, and the relation between them is:

$f_d=-\frac{f_0}{C}\×v\×\cos \mathrm{\θ}$

Wherein, θ is the angle between terminal moving direction and the signal propagation direction; V is the terminal movement velocity; C is a propagation velocity of electromagnetic wave; f ₀Be carrier frequency.

The LTE system is for portable terminal, guarantee mobile subscriber's system performance optimum of 15km/h and following speed, and can provide high performance service to the mobile subscriber of 15～120km/h, and keep 120～350km/h mobile subscriber's service, be higher than the 350km/h mobile subscriber and do not fall net.In this velocity interval, Doppler frequency shift surpasses 400Hz, and base station and terminal must support enough compensate of frequency deviation technology could satisfy operation quality requirement.

For receiver, estimate and transmitter between frequency error and to finish correction of frequency errors be the function that receiver must be finished.Terminal receives f _dFrequency displacement, send upward signal after the terminal locking downstream signal frequencies, up reception will have 2*f _dFrequency displacement.

Frequency deviation schematic diagram in existing a kind of terminal moving process as shown in Figure 1, the direction of relative movement of terminal and base station is different, can produce positive and negative different frequency deviation, establishes f ₀Be the tranmitting frequency of base station, when terminal to away from the motion of the direction of base station the time, can produce negative frequency deviation-f _d, the frequency that terminal receives is f ₀-f _d, the frequency that the base station receives is f ₀-2*f _dWhen terminal near the motion of the direction of base station the time, can produce positive frequency deviation f _d, the frequency that terminal receives is f ₀+ f _d, the frequency that the base station receives is f ₀+ 2*f _dWhen terminal is moved between two base stations, when driving towards another base station from a base station, terminal can frequency of occurrences saltus step, from frequency f ₀-f _dBe transferred to frequency f ₀+ f _d, terminal will have 2*f _dFrequency hopping.2*f _dNo matter for base station receiver, or terminal receiver all will be a no small challenge, and excessive frequency offset can cause communication quality to descend, and can cause service disruption in the time of serious, especially under high-speed mobile environment.

If can not correctly estimate frequency deviation and compensate, systematic function will reduce greatly so, especially when frequency deviation is big (when the counterpart terminal movement velocity is higher), use pilot tone to do frequency offset estimating in the prior art, the frequency deviation region that can estimate is little, the complexity height, when there was big frequency deviation in system, anti-noise ability descended to some extent.

Summary of the invention

The problem to be solved in the present invention provides a kind of frequency deviation estimating method and device based on data, uses pilot tone to do frequency offset estimating in the prior art to overcome, and the frequency deviation region of estimation is little, the defective that complexity is high.

For achieving the above object, technical scheme of the present invention provides a kind of frequency deviation estimating method based on data, said method comprising the steps of: the pilot bit frequency domain channel estimated value of obtaining the targeted customer; According to described pilot bit frequency domain channel estimated value, obtain and only contain the phase information that frequency deviation causes; According to described phase information, obtain between different OFDM symbol datas or OFDM symbol different sub carrier on the phase difference of data; Obtain frequency deviation value according to described phase difference.

Further, in the step of the described pilot bit frequency domain channel estimated value of obtaining the targeted customer, specifically comprise: according to formula

1≤k≤M and

1≤k≤M obtains targeted customer's pilot bit frequency domain channel estimated value, wherein

Be the channel estimation value of pilot tone 1, Be the channel estimation value of pilot tone 2,

Be the frequency domain receiving sequence of pilot tone 1,

Be the frequency domain receiving sequence of pilot tone 2, X ^(m)(k) be local pilot tone sign indicating number, length is M, and m is the user.

Further, obtain in the step that only contains the phase information that frequency deviation causes, specifically comprise: utilize the symbol data on the described pilot bit frequency domain channel estimated value demodulating data position described; Correspond to the territory (for example, LTE system uplink " territory of modulation symbol " is exactly a time domain, and descending " territory of modulation symbol " is exactly frequency domain) of modulation symbol, the rectification symbol, and declare data firmly, the data after declaring firmly are modulated to symbol again; The conjugation that multiply by the symbol after the judgement with unsentenced symbol obtains a complex values, and described complex values is asked phase place.

Further, in the described step of obtaining the phase difference between different OFDM symbol datas, specifically comprise: according to formula

Calculate the phase difference φ between different OFDM symbol datas ^(m), wherein

With

Be the phase place of different OFDM symbol datas, i is an OFDM symbol sequence number, and x is at interval a symbolic number between two OFDM symbols that calculate phase differences, and m is the user.

Further, the described step of obtaining frequency deviation value according to phase difference specifically comprises: according to formula

Calculate frequency deviation value f, wherein Δ φ ^(m)Be the phase difference between different OFDM symbol datas, x is at interval a symbolic number between two OFDM symbols that calculate phase differences.

Further, in the described step of obtaining the phase difference of data on the OFDM symbol different sub carrier, specifically comprise: will be level and smooth to the phase place grouping that described complex values is tried to achieve, be divided into Q group, every group of M/Q element; According to formula

1≤s≤Q, 1≤j≤M/Q obtain in this OFDM symbol the phase place of data on each subcarrier

Wherein

Be the phase place that described complex values is tried to achieve, s is the sequence number of group, the sequence number of element during j is every group; According to formula

Calculate the phase difference φ of data on the different sub carrier ^(m), wherein

With

Be respectively the phase place of data on the different sub carrier group, g is at interval a number between two sub carrier group of calculating phase differences.

Further, the described step of obtaining frequency deviation value according to phase difference specifically comprises: according to formula

Calculate frequency deviation value f, wherein Δ φ ^(m)Be the phase difference of data on the different sub carrier, Δ f is a sub-carrier frequencies, and g is at interval a number between two sub carrier group of calculating phase differences, and Q is the grouping number.

Further, after the described step of obtaining frequency deviation value according to phase difference, also comprise: judge according to described frequency deviation value and select branch, and obtain the frequency deviation initial value corresponding with described branch; Frequency deviation initial value according to described branch correspondence carries out frequency offset estimating in conjunction with pilot tone.

Further, carry out in conjunction with pilot tone specifically comprising in the step of frequency offset estimating at described frequency deviation initial value: with the pilot bit frequency domain channel estimated value of user m according to branch's correspondence

Be divided into the Q section, in every section, carry out frequency domain smoothing, and to continuous N _SmoothingPilot bit frequency domain channel estimated value on=M/Q subcarrier is asked on average, obtains mean value

With

According to formula

$\left\{\begin{array}{c}\mathrm{\Δ\Δ}{f}_{s,\mathrm{ka}}=\frac{\∠\left({\stackrel{\‾}{H}}_{2,s}^{\left(m\right)}\right)/\left({\stackrel{\‾}{H}}_{1,s}^{\left(m\right)}\right)}{2\mathrm{\π}\·t}-\mathrm{\Δ}{f}_0+l\×2000\\ \mathrm{\Δ\Δ}{f}_{\mathrm{ka}}=\frac{1}{Q}\underset{s}{\overset{Q}{\mathrm{\Σ}}}\mathrm{\Δ\Δ}{f}_{s,\mathrm{ka}}\\ \mathrm{\Δ}{f}_{\mathrm{ka}}=\mathrm{\Δ}{f}_0+\mathrm{\Δ\Δ}{f}_{\mathrm{ka}}\end{array}\right.$

Obtain the frequency offset estimating Δ _Fka, wherein ∠ is for asking the computing of argument of a complex number main value, and t is two time intervals between the pilot tone of calculating phase differences, Δ f ₀Be the frequency deviation initial value corresponding with branch, l is for making Δ Δ f _{S, ka}The integer of ∈ (1000,1000), s is the sequence number of group, Δ Δ f _{S, ka}With Δ Δ f _KaBe middle frequency deviation value.

Further, at the described mean value that obtains

With

Step in, specifically comprise: according to formula

1≤s≤Q, 1≤j≤N _SmoothmgWith

1≤s≤Q, 1≤j≤N _SmoothingObtain mean value

With

Wherein s is the sequence number of group, the sequence number of element during j is every group.

Technical scheme of the present invention also provides a kind of frequency deviation estimation device based on data, and described device comprises: pilot bit frequency domain channel estimated value acquiring unit is used to obtain targeted customer's pilot bit frequency domain channel estimated value; The phase information acquiring unit is used for according to described pilot bit frequency domain channel estimated value, obtains only to contain the phase information that frequency deviation causes; The phase difference acquiring unit is used for according to described phase information, obtain between different OFDM symbol datas or OFDM symbol different sub carrier on the phase difference of data; The frequency deviation value acquiring unit is used for obtaining frequency deviation value according to described phase difference.

Further, described device also comprises: frequency deviation initial value acquiring unit, and the frequency deviation value that is used for obtaining according to described frequency deviation value acquiring unit is judged selection branch, and obtains the frequency deviation initial value corresponding with described branch; Frequency deviation estimating unit is used for carrying out frequency offset estimating according to the frequency deviation initial value of described branch correspondence in conjunction with pilot tone.

Compared with prior art, beneficial effect of the present invention is as follows:

The phase difference estimation frequency deviation initial value scope of the present invention after according to data demodulates, estimate frequency deviation value with the frequency deviation initial value scope that estimates in conjunction with pilot tone again, thereby improve receiver performance frequency offset estimating ability, can estimate the relative frequency deviation between base station and the terminal effectively, reduce ofdm system owing to sub-carrier orthogonality being destroyed the interference that is brought, improve estimation and the compensation range of receiver to frequency deviation, when especially having big frequency deviation in the high-speed mobile environment link, the frequency deviation value that exists in the estimating system more accurately is for telecommunication service quality provides reliable guarantee.

Description of drawings

Fig. 1 is the frequency deviation schematic diagram in a kind of terminal moving process of prior art;

Fig. 2 is the flow chart of a kind of frequency deviation estimating method based on data of the embodiment of the invention one;

Fig. 3 is the flow chart of a kind of frequency deviation estimating method based on data of the embodiment of the invention two;

Fig. 4 is a kind of frequency deviation branch schematic diagram of the embodiment of the invention;

Fig. 5 is the flow chart of a kind of frequency deviation estimating method based on data of the embodiment of the invention three;

Fig. 6 is the flow chart of a kind of frequency deviation estimating method based on data of the embodiment of the invention four;

Fig. 7 is the structural representation of a kind of frequency deviation estimation device based on data of the embodiment of the invention five.

Embodiment

Below in conjunction with drawings and Examples, the specific embodiment of the present invention is described in further detail.Following examples are used to illustrate the present invention, but are not used for limiting the scope of the invention.

Embodiment one

A kind of frequency deviation estimating method based on data of the embodiment of the invention may further comprise the steps as shown in Figure 2:

Step s201 obtains targeted customer's pilot bit frequency domain channel estimated value.In the present embodiment, according to following formula

$H_1^{\left(m\right)}\left(k\right)=\frac{Y_1^{\left(m\right)}\left(k\right)}{X^m\left(k\right)},$ 1≤k≤M and

$H_2^{\left(m\right)}\left(k\right)=\frac{Y_2^{\left(m\right)}\left(k\right)}{X^m\left(k\right)},$ 1≤k≤M

Obtain the pilot bit frequency domain channel estimated value of user m, wherein

Be the channel estimation value of pilot tone 1,

Be the channel estimation value of pilot tone 2,

Be the frequency domain receiving sequence of pilot tone 1,

Be the frequency domain receiving sequence of pilot tone 2, X ^(m)(k) be local pilot tone sign indicating number, length is M, φ ₁And φ ₂The t that comprises pilot tone 1 correspondence respectively ₁T with pilot tone 2 correspondences ₂Channel phase characteristic and frequency deviation phase information constantly.

Step s202 according to described pilot bit frequency domain channel estimated value, obtains and only contains the phase information that frequency deviation causes.In the present embodiment, with pilot bit channel estimation value demodulating data position, correspond to the territory that is modulated to symbol, PUSCH (Physical Uplink Shared Channel for example, up link is shared physical channel), then need demodulating data is done inversefouriertransform, rectification is also declared firmly, obtains phase difference between two data symbols; PDSCH (Physical Downlink Shared Channel, down link is shared physical channel) then declares firmly, obtains phase difference between two data symbols.

Adopt MMSE (Minimum MeanSquare Error, least mean-square error) demodulation method (also can adopt other demodulation methods, for example MF (Matched Filtering, matched filtering), ZF (Zero-Forcing, ZF)),

${\hat{s}}_i^{\left(m\right)}={({H_{h\_\mathrm{slot}\_i}^{\left(m\right)}}^H{H}_{h\_\mathrm{slot}\_i}^{\left(m\right)}+{\mathrm{\σ}}^2)}^{-1}{H_{h\_\mathrm{slot}\_i}^{\left(m\right)}}^H{r}_i^{\left(m\right)};$

If the QPSK symbol is a time-domain signal, then

If the QPSK symbol is a frequency-region signal, then

The rectification data

And carry out hard decision, " hard " expression hard decision function; With the data after declaring firmly

Be modulated to symbol again

The planisphere of modulation constellation and rectification is identical.

Multiply by the conjugation of the symbol after the judgement with unsentenced symbol, the complex values that obtains asked phase place, L is adjustable parameter.

Step s203 according to described phase information, obtains the phase difference between different OFDM symbol datas.In the present embodiment, according to formula

Calculate the phase difference φ between different OFDM symbol datas ^(m), wherein

With

Be the phase place of different OFDM symbol datas, i is an OFDM symbol sequence number, and x is at interval a symbolic number between two OFDM symbols that calculate phase differences.

Step s204 obtains frequency deviation value according to described phase difference.In the present embodiment, according to formula

Calculate frequency deviation value f, wherein Δ φ ^(m)Be the phase difference between different OFDM symbol datas, x is at interval a symbolic number between two OFDM symbols that calculate phase differences.

Embodiment two

A kind of frequency deviation estimating method based on data of the embodiment of the invention as shown in Figure 3, wherein step s301～s304 is identical with step s201～s204 among the embodiment one.With reference to Fig. 3, present embodiment is after step s304, and is further comprising the steps of:

Step s305 judges selection branch according to described frequency deviation value, and obtains the frequency deviation initial value corresponding with described branch.In the present embodiment, according to the f that estimates frequency deviation is carried out branch and selects, a kind of frequency deviation branch schematic diagram of present embodiment as shown in Figure 4, f _Th,-f _ThBe branch's separation, f ₁, f ₂, f ₃Be the frequency deviation initial value of branch's correspondence, f _Th,-f _Th, f ₁, f ₂, f ₃And branch's number all is parameter, obtains by emulation or outfield actual environment.

When-f _Th≤ f≤f _ThThe time,

Select branch 2, Δ f ₀=f ₂

As f＞f _ThThe time,

Select branch 3, Δ f ₀=f ₃

When f＜-f _ThThe time,

Select branch 1, Δ f ₀=f ₁

Step s306 carries out frequency offset estimating according to the frequency deviation initial value of described branch correspondence in conjunction with pilot tone.In the present embodiment, at first, to the channel estimation value of user m

Be divided into the Q section, in every section, carry out frequency domain smoothing.With continuous N _SmoothingChannel estimation value on=M/Q subcarrier is asked on average, promptly according to formula

1≤s≤Q, 1≤j≤N _SmoothingWith

1≤s≤Q, 1≤j≤N _SmoothingObtain mean value

With Wherein s is the sequence number of group, the sequence number of element during j is every group.

Then, with Δ f ₀Channel estimation value with pilot bit

Combine and carry out frequency offset estimating.Select corresponding initial frequency deviation Δ f with branch ₀Participate in current residual frequency deviation and calculate Δ f ₀Can be that each reception antenna obtains respectively, promptly obtain Δ f _{0, ka}, also can be to obtain again respectively to average, i.e. Δ f ₀:

Present embodiment is according to formula

$\left\{\begin{array}{c}\mathrm{\Δ\Δ}{f}_{s,\mathrm{ka}}=\frac{\∠\left({\stackrel{\‾}{H}}_{2,s}^{\left(m\right)}\right)/\left({\stackrel{\‾}{H}}_{1,s}^{\left(m\right)}\right)}{2\mathrm{\π}\·t}-\mathrm{\Δ}{f}_0+l\×2000\\ \mathrm{\Δ\Δ}{f}_{\mathrm{ka}}=\frac{1}{Q}\underset{s}{\overset{Q}{\mathrm{\Σ}}}\mathrm{\Δ\Δ}{f}_{s,\mathrm{ka}}\\ \mathrm{\Δ}{f}_{\mathrm{ka}}=\mathrm{\Δ}{f}_0+\mathrm{\Δ\Δ}{f}_{\mathrm{ka}}\end{array}\right.$

Obtain frequency offset estimating Δ f _Ka, wherein ∠ is for asking argument of a complex number main value computing (promptly asking phase place), and t is two time intervals between the pilot tone of calculating phase differences, Δ f ₀Be the frequency deviation initial value corresponding with branch, l is for making Δ Δ f _{S, ka}The integer of ∈ (1000,1000), s is the sequence number of group, Δ Δ f _{S, ka}With Δ Δ f _KaBe middle frequency deviation value.

Embodiment three

A kind of frequency deviation estimating method based on data of the embodiment of the invention as shown in Figure 5, wherein step s501～s502 is identical with step s201～s202 among the embodiment one.With reference to Fig. 5, present embodiment may further comprise the steps after step s502:

Step s503 according to described phase information, obtains the phase difference of data on the OFDM symbol different sub carrier.In the present embodiment, at first will be level and smooth to the phase place grouping that described complex values is tried to achieve, be divided into Q group, every group of M/Q element.Then according to formula

1≤s≤Q, 1≤j≤M/Q obtain in this OFDM symbol the phase place of data on each subcarrier Wherein Be the phase place that described complex values is tried to achieve, s is the sequence number of group, the sequence number of element during j is every group.At last according to formula

Calculate the phase difference φ of data on the different sub carrier ^(m), wherein

With

Be respectively the phase place of data on the different sub carrier group, g is at interval a number between two sub carrier group of calculating phase differences.

Step s504 is according to formula

Calculate frequency deviation value f, wherein Δ φ ^(m)Be the phase difference of data on the different sub carrier, M is the length of a shared subcarrier of OFDM symbol, and Δ f is sub-carrier frequencies (in LTE, Δ f is 15kHz), and g is at interval a number between two sub carrier group of calculating phase differences, and Q is the grouping number.

Embodiment four

A kind of frequency deviation estimating method based on data of the embodiment of the invention as shown in Figure 6, wherein step s601～s604 is identical with step s501～s504 among the embodiment one.With reference to Fig. 6, present embodiment also comprises step s605 and s606 after step s604, and these two steps are identical with step s305 and s306 among the embodiment two respectively.

Embodiment five

The structure of a kind of frequency deviation estimation device based on data of the embodiment of the invention comprises pilot bit frequency domain channel estimated value acquiring unit, phase information acquiring unit, phase difference acquiring unit, frequency deviation value acquiring unit, frequency deviation initial value acquiring unit and frequency deviation estimating unit as shown in Figure 7.Wherein, the phase information acquiring unit is connected with the phase difference acquiring unit with pilot bit frequency domain channel estimated value acquiring unit respectively, the frequency deviation value acquiring unit is connected frequency deviation initial value acquiring unit and frequency deviation estimating unit with the phase difference acquiring unit with frequency deviation initial value acquiring unit respectively.

Pilot bit frequency domain channel estimated value acquiring unit is used to obtain targeted customer's pilot bit frequency domain channel estimated value; The phase information acquiring unit is used for according to described pilot bit frequency domain channel estimated value, obtains only to contain the phase information that frequency deviation causes; The phase difference acquiring unit is used for according to described phase information, obtain between different OFDM symbol datas or OFDM symbol different sub carrier on the phase difference of data; The frequency deviation value acquiring unit is used for obtaining frequency deviation value according to described phase difference.Frequency deviation initial value acquiring unit is used for judging selection branch according to described frequency deviation value, and obtains the frequency deviation initial value corresponding with described branch; Frequency deviation estimating unit is used for carrying out frequency offset estimating according to the frequency deviation initial value of described branch correspondence in conjunction with pilot tone.

The phase difference estimation frequency deviation initial value scope of the present invention after according to data demodulates, estimate frequency deviation value with the frequency deviation initial value scope that estimates in conjunction with pilot tone again, thereby improve receiver performance frequency offset estimating ability, can estimate the relative frequency deviation between base station and the terminal effectively, reduce ofdm system owing to sub-carrier orthogonality being destroyed the interference that is brought, improve estimation and the compensation range of receiver to frequency deviation, owing to used branch's system of selection, therefore increase base station and terminal greatly and carry out the limit of power of frequency offset estimating, the present invention makes the receiver can accurately, the stable frequency offset correction that carries out.When especially having big frequency deviation in the high-speed mobile environment link, the frequency deviation value that exists in the estimating system more accurately is for telecommunication service quality provides reliable guarantee.

The above only is a preferred implementation of the present invention; should be pointed out that for those skilled in the art, under the prerequisite that does not break away from the technology of the present invention principle; can also make some improvements and modifications, these improvements and modifications also should be considered as protection scope of the present invention.

Claims (12)

1. the frequency deviation estimating method based on data is characterized in that, said method comprising the steps of:

Obtain targeted customer's pilot bit frequency domain channel estimated value;

According to described pilot bit frequency domain channel estimated value, obtain and only contain the phase information that frequency deviation causes;

According to described phase information, obtain between different OFDM symbol datas or OFDM symbol different sub carrier on the phase difference of data;

Obtain frequency deviation value according to described phase difference.

2. the frequency deviation estimating method based on data as claimed in claim 1 is characterized in that, in the step of the described pilot bit frequency domain channel estimated value of obtaining the targeted customer, specifically comprises:

According to formula

1≤k≤M and

1≤k≤M obtains targeted customer's pilot bit frequency domain channel estimated value, wherein

Be the channel estimation value of pilot tone 1,

Be the channel estimation value of pilot tone 2,

Be the frequency domain receiving sequence of pilot tone 1, The frequency domain receiving sequence of frequency 2, X ^(m)(k) be local pilot tone sign indicating number, length is M, and m is the user.

3. the frequency deviation estimating method based on data as claimed in claim 1 is characterized in that, obtains in the step that only contains the phase information that frequency deviation causes described, specifically comprises:

Utilize the symbol data on the described pilot bit frequency domain channel estimated value demodulating data position;

Correspond to the territory of modulation symbol, the rectification symbol, and declare data firmly, the data after declaring firmly are modulated to symbol again;

The conjugation that multiply by the symbol after the judgement with unsentenced symbol obtains a complex values, and described complex values is asked phase place.

4. the frequency deviation estimating method based on data as claimed in claim 3 is characterized in that, in the described step of obtaining the phase difference between different OFDM symbol datas, specifically comprises:

According to formula Calculate the phase difference φ between different OFDM symbol datas ^(m), wherein

With Be the phase place of different OFDM symbol datas, i is an OFDM symbol sequence number, and x is at interval a symbolic number between two OFDM symbols that calculate phase differences, and m is the user.

5. the frequency deviation estimating method based on data as claimed in claim 4 is characterized in that, the described step of obtaining frequency deviation value according to phase difference specifically comprises:

According to formula

Calculate frequency deviation value f, wherein Δ φ ^(m)Be the phase difference between different OFDM symbol datas, x is at interval a symbolic number between two OFDM symbols that calculate phase differences.

6. the frequency deviation estimating method based on data as claimed in claim 3 is characterized in that, in the described step of obtaining the phase difference of data on the OFDM symbol different sub carrier, specifically comprises:

Will be level and smooth to the phase place grouping that described complex values is tried to achieve, be divided into Q group, every group of M/Q element;

According to formula 1≤s≤Q, 1≤j≤M/Q obtain in this OFDM symbol the phase place of data on each subcarrier

Wherein Be the phase place that described complex values is tried to achieve, s is the sequence number of group, the sequence number of element during j is every group;

According to formula

Calculate the phase difference φ of data on the different sub carrier ^(m), wherein

With

Be respectively the phase place of data on the different sub carrier group, g is at interval a number between two sub carrier group of calculating phase differences.

7. the frequency deviation estimating method based on data as claimed in claim 6 is characterized in that, the described step of obtaining frequency deviation value according to phase difference specifically comprises:

According to formula

Calculate frequency deviation value f, wherein Δ φ ^(m)Be the phase difference of data on the different sub carrier, Δ f is a sub-carrier frequencies, and g is at interval a number between two sub carrier group of calculating phase differences, and Q is the grouping number.

8. as each described frequency deviation estimating method of claim 1 to 7, it is characterized in that, after the described step of obtaining frequency deviation value according to phase difference, also comprise based on data:

Judge selection branch according to described frequency deviation value, and obtain the frequency deviation initial value corresponding with described branch;

Frequency deviation initial value according to described branch correspondence carries out frequency offset estimating in conjunction with pilot tone.

9. the frequency deviation estimating method based on data as claimed in claim 8 is characterized in that, carries out in conjunction with pilot tone specifically comprising in the step of frequency offset estimating at described frequency deviation initial value according to branch's correspondence:

Pilot bit frequency domain channel estimated value with user m

Be divided into the Q section, in every section, carry out frequency domain smoothing, and to continuous N _SmoothingPilot bit frequency domain channel estimated value on=M/Q subcarrier is asked on average, obtains mean value

With

According to formula

$\left\{\begin{array}{c}\mathrm{\Δ\Δ}{f}_{s,\mathrm{ka}}=\frac{\∠\left({\stackrel{\‾}{H}}_{2,s}^{\left(m\right)}\right)/\left({\stackrel{\‾}{H}}_{1,s}^{\left(m\right)}\right)}{2\mathrm{\π}\·t}-\mathrm{\Δ}{f}_0+l\×2000\\ \mathrm{\Δ\Δ}{f}_{\mathrm{ka}}=\frac{1}{Q}\underset{s}{\overset{Q}{\mathrm{\Σ}}}\mathrm{\Δ\Δ}{f}_{s,\mathrm{ka}}\\ \mathrm{\Δ}{f}_{\mathrm{ka}}=\mathrm{\Δ}{f}_0+\mathrm{\Δ\Δ}{f}_{\mathrm{ka}}\end{array}\right.$

Obtain frequency offset estimating Δ f _Ka, wherein ∠ is for asking the computing of argument of a complex number main value, and t is two time intervals between the pilot tone of calculating phase differences, Δ f ₀Be the frequency deviation initial value corresponding with branch, l is for making Δ Δ f _{S, ka}The integer of ∈ (1000,1000), s is the sequence number of group, Δ Δ f _{S, ka}With Δ Δ f _KaBe middle frequency deviation value.

10. the frequency deviation estimating method based on data as claimed in claim 9 is characterized in that, at the described mean value that obtains With

Step in, specifically comprise:

According to formula

1≤s≤Q, 1≤j≤N _SmoothingWith

1≤s≤Q, 1≤j≤N _SmoothingObtain mean value

With

Wherein s is the sequence number of group, the sequence number of element during j is every group.

11. the frequency deviation estimation device based on data is characterized in that, described device comprises:

Pilot bit frequency domain channel estimated value acquiring unit is used to obtain targeted customer's pilot bit frequency domain channel estimated value;

The phase information acquiring unit is used for according to described pilot bit frequency domain channel estimated value, obtains only to contain the phase information that frequency deviation causes;

The phase difference acquiring unit is used for according to described phase information, obtain between different OFDM symbol datas or OFDM symbol different sub carrier on the phase difference of data;

The frequency deviation value acquiring unit is used for obtaining frequency deviation value according to described phase difference.

12. the frequency deviation estimation device based on data as claimed in claim 11 is characterized in that, described device also comprises:

Frequency deviation initial value acquiring unit, the frequency deviation value that is used for obtaining according to described frequency deviation value acquiring unit is judged selection branch, and obtains the frequency deviation initial value corresponding with described branch;

Frequency deviation estimating unit is used for carrying out frequency offset estimating according to the frequency deviation initial value of described branch correspondence in conjunction with pilot tone.

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