CN101364964B - Frequency bias estimation method for radio communication system uplink - Google Patents

Abstract

The invention provides a frequency deviation estimation method used in the uplink of a wireless communication system. The method comprises the following steps: step S102, a reference mark is constructed in the frame structure of a transmitted signal at the transmitting terminal, and the transmitted signal is transmitted to a receiving terminal; step S104, after time synchronization is conducted to the received signal, the receiving terminal extracts the reference mark from the signal; step S106, phase comparison is made between the reference mark from the transmitting terminal and the reference mark extracted at the receiving terminal, and the comparison result is recorded into a phase deviation information value; and step S108, the frequency deviation estimation value is determined according to the length of the reference mark of the transmitted signal and the phase deviation information value. While ensuring the synchronization precision, the method does not increase the resource burden of the system, and the operand is very small. Therefore, the method is favorable for projects to be realized.

Description

The frequency deviation estimating method that is used for radio communication system up link

Technical field

The present invention relates to the frequency deviation estimating method in a kind of E-UTRA of being applied in (Enhanced UTRA) radio communication system up link and carry out Frequency Synchronization according to this method.

Background technology

Development along with Digital Signal Processing and high speed device; Initial OFDM (the Orthogonal Frequency Division Multiplexing that realizes; Abbreviate OFDM as) technology obstacle do not existed; OFDM is at DAB (Digital AudioBroadcast; Abbreviate digital audio broadcasting as), obtained successful application in DVB (Digital Video Broadcast abbreviates DVB as) and the WLAN systems such as (Wireless Local-area Network abbreviate WLAN as).OFDM utilizes the orthogonality between each number of sub-carrier, allows the frequency spectrum of subchannel overlapped, can utilize frequency spectrum resource largely.It passes through string and conversion with high-speed data-flow; Make the data symbol persistence length on each subcarrier increase relatively; Thereby reduced the ISI that temporal dispersion brought (Inter-Symbol Interfere abbreviates intersymbol interference as) of wireless channel effectively, simultaneously because the bandwidth relative narrower of each subchannel; Equilibrium just can be carried out respectively each subcarrier, has so just reduced complexity balanced in the receiver.Because These characteristics, this technology is widely used in recent years.

The feasible demand to frequency spectrum of the surge of high speed business and number of users sharply increases, and frequency spectrum resource is limited, and in order to solve this contradiction, industry can further improve the method for the availability of frequency spectrum always in continuous searching.Along with deepening continuously of Long Term Evolution (LTE) research work, in the E-UTRA wireless communication system, select to adopt the OFDM modulation technique, can improve the availability of frequency spectrum on the one hand, can effectively resist frequency selective fading on the other hand.

But the OFDM technology is when having above advantage, and it is very responsive to frequency shift (FS) to eliminate they self shortcoming: OFDM.In order to adopt the OFDM technology, carrier deviation is compared with subcarrier spacing, must be very little, otherwise the demodulation performance of OFDM will be received very big influence.Yet there is time variation in wireless channel; The frequency shift (FS) of wireless signal can appear in transmission course; Doppler frequency shift for example; The frequency departure that perhaps exists between transmitter carrier frequency and the receiver local oscillator can make that all the orthogonality between the ofdm system subcarrier is destroyed, thereby causes the signal between the subchannel to interfere with each other (ICI).Simultaneously; The symbol timing of ofdm system must drop in the scope of Cyclic Prefix (CP) permission; Otherwise at this moment the information of the non-current code element that comprises of FFT (Fast Fourier Transform abbreviates FFT as) demodulation window will cause the interference between code element.

And it is regularly synchronous for ofdm system; Also can adopt known information to carry out Synchronization Analysis, like CP information, be current popular processing method; But be based on the resultant extra resource of system that can not need of CP information and realize that synchronously, amount of calculation is also little simultaneously.But it is comparatively smooth that its shortcoming is a relevant peaks, is unfavorable for judgement, and frequency offset estimation range is little simultaneously.So, generally as timing coarse synchronization.In addition, utilize the special construction of pilot tone/synchronizing symbol to carry out the synchronously smart of timing.Frequency Synchronization adopts special leading design to carry out synchronously.

Therefore, need a kind of solution that is used to utilize the frequency offset estimating that has anchor-frame structure realization up link now, can solve the problem in the above-mentioned correlation technique.

Summary of the invention

The purpose of this invention is to provide the frequency deviation estimating method in a kind of E-UTRA of being applied in radio communication system up link; A kind of time frequency deviation rough estimate and the scheme of accurately estimating in E-UTRA communication system up link promptly is provided, thereby makes the base station receiving terminal in the E-UTRA radio communication system up link under with the cost of small system resources, to realize accurate frequency offset estimating through low complexity algorithm.

The invention provides a kind of frequency deviation estimating method that is used for radio communication system up link, may further comprise the steps: step S102, transmitting terminal is constructed reference symbol in the frame structure that transmits, and will transmit and be transmitted into receiving terminal; Step S104, receiving terminal extracts reference symbol from signal after carrying out time synchronized to the received signal; Step S106, the reference symbol of the end of spontaneous emission is in the future carried out bit comparison mutually with the reference symbol of extracting at receiving terminal, and comparative result is recorded as the phase-shift information value; And step S108, confirm the frequency offset estimating value according to the length and the phase-shift information value of the reference symbol that transmits.

Wherein, reference symbol comprises a reference sequences or a plurality of identical reference sequences, and reference symbol is arranged in the data block of the pre-position that transmits, and the quantity of data block is two.

Step S106 may further comprise the steps: with the reference symbol that receives respectively with transmit in the original reference symbol carry out phase place and eliminate, the phase difference that record obtains obtains two groups of phase-shift information value: θ ₁(k)=angle (s* (k) r ₁(k)), θ ₂(k)=angle (s* (k) r ₂(k)), wherein, k=1,2 ..., L, L are the length of reference sequences, r ₁(k), r ₂(k) represent respectively corresponding to the reference symbol in two data blocks.

Step S108 may further comprise the steps: step S108-2, will subtract each other corresponding to the phase-shift information value of two adjacent in same data block reference sequences and obtain two groups of phase difference sequences; Step S108-4 confirms the arithmetic mean of each item in two groups of phase difference sequences to obtain the two group phase difference sequences relevant with reference sequences length; And step S108-6, the two group phase difference sequences relevant with reference sequences length are averaged, and obtain the estimated frequency shift amount according to the length of reference sequences.

Step S108-2 may further comprise the steps: basis respectively ${{\widetilde{\mathrm{\φ}}}_1}^p\left(m\right)={{\mathrm{\θ}}_1}^{p+1}\left(m\right)-{{\mathrm{\θ}}_1}^p\left(m\right),$ With ${{\widetilde{\mathrm{\φ}}}_2}^p\left(m\right)={{\mathrm{\θ}}_2}^{p+1}\left(m\right)-{{\mathrm{\θ}}_2}^p\left(m\right)$ Calculate phase difference sequence corresponding to two data blocks, wherein, p=1,2 ..., P-1, m=1,2 ..., M, θ ₁ ^p(m) be phase difference sequence θ ₁(k) M+m value of (P-1) in, θ ₂ ^p(m) be phase difference sequence θ ₂(k) M+m value of (P-1) in, and $M=\frac{L}{P},$ Wherein, P is the number of reference sequences in the reference symbol.

Step S108-4 may further comprise the steps: basis respectively ${\mathrm{\φ}}_1\left(m\right)=\frac{1}{P-1}\underset{P=1}{\overset{P-1}{\mathrm{\Σ}}}{{\widetilde{\mathrm{\φ}}}_1}^P\left(m\right),$ With ${\mathrm{\φ}}_2\left(m\right)=\frac{1}{P-1}\underset{P=1}{\overset{P-1}{\mathrm{\Σ}}}{{\widetilde{\mathrm{\φ}}}_2}^P\left(m\right)$ Confirm the arithmetic mean of each item in two groups of phase difference sequences, thereby obtain the two group phase difference sequences relevant with reference sequences length, wherein, m=1,2 ..., M.

Step S108-6 may further comprise the steps: according to Phase difference sequence corresponding to two data blocks is averaged, and according to

Confirm estimated frequency offset, wherein, N _FFTBe the length of the FFT of OFDM symbol, f is a subcarrier spacing.

This method is further comprising the steps of: utilize the estimated frequency shift amount to carry out Frequency Synchronization to the received signal, through the later estimated value that transmits of Frequency Synchronization

Can be expressed as ${\tilde{s}}_k=R_k{e}^{2\mathrm{\π}{F}_{\mathrm{Offset}}t}=s_k{e}^{-2\mathrm{\π}(\mathrm{\Δ\; f}-F_{\mathrm{Offset}})t},$ Wherein, R _k=s _ke ^{-2 π Δ ft}The signal that expression receives, Δ f representes the frequency offset of transmitting-receiving two-end.

The present invention is applied in frequency deviation estimating method in the E-UTRA radio communication system up link when guaranteeing synchronization accuracy, does not increase the system resource burden, and operand is very little, is beneficial to very much Project Realization.

Other features and advantages of the present invention will be set forth in specification subsequently, and, partly from specification, become apparent, perhaps understand by embodiment of the present invention.The object of the invention can be realized through the structure that in the specification of being write, claims and accompanying drawing, is particularly pointed out and obtained with other advantages.

Description of drawings

Accompanying drawing described herein is used to provide further understanding of the present invention, constitutes the application's a part, and illustrative examples of the present invention and explanation thereof are used to explain the present invention, do not constitute improper qualification of the present invention.In the accompanying drawings:

Fig. 1 illustrates the flow chart that is used for the frequency deviation estimating method of radio communication system up link according to of the present invention;

Fig. 2 illustrates being used for E-UTRA radio communication system up link frequency deviation estimating method and carrying out synchronous flow chart according to the frequency offset estimating value that said frequency deviation estimating method obtains according to first embodiment of the invention;

Fig. 3 is the sketch map that illustrates according to the reference symbol in the frequency deviation estimating method that is used for the E-UTRA radio communication system up link of the embodiment of the invention and the position in structure of time slot thereof (among the figure be example with P=2); And

Fig. 4 illustrates being used for E-UTRA radio communication system up link frequency deviation estimating method and carrying out synchronous flow chart according to the frequency offset estimating value that said frequency deviation estimating method obtains according to second embodiment of the invention.

Embodiment

To combine accompanying drawing to specify embodiments of the invention below.

Fig. 1 illustrates the flow chart that is used for the frequency deviation estimating method of radio communication system up link according to of the present invention.With reference to Fig. 1, be used for the frequency deviation estimating method of radio communication system up link, may further comprise the steps: step S102, transmitting terminal is constructed reference symbol in the frame structure that transmits, and will transmit and be transmitted into receiving terminal; Step S104, receiving terminal extracts reference symbol from signal after carrying out time synchronized to the received signal; Step S106, the reference symbol of the end of spontaneous emission is in the future carried out bit comparison mutually with the reference symbol of extracting at receiving terminal, and comparative result is recorded as the phase-shift information value; And step S108, confirm the frequency offset estimating value according to the length and the phase-shift information value of the reference symbol that transmits.

Wherein, reference symbol comprises a reference sequences or a plurality of identical reference sequences, and reference symbol is arranged in the data block of the pre-position that transmits, and the quantity of data block is two.

Step S106 may further comprise the steps: with the reference symbol that receives respectively with transmit in the original reference symbol carry out phase place and eliminate, the phase difference that record obtains obtains two groups of phase-shift information value: θ ₁(k)=angle (s* (k) r ₁(k)), θ ₂(k)=angle (s* (k) r ₂(k)), wherein, k=1,2 ..., L, L are the length of reference sequences, r ₁(k), r ₂(k) represent respectively corresponding to the reference symbol in two data blocks.

Step S108 may further comprise the steps: step S108-2, will subtract each other corresponding to the phase-shift information value of two adjacent in same data block reference sequences and obtain two groups of phase difference sequences; Step S108-4 confirms the arithmetic mean of each item in two groups of phase difference sequences to obtain the two group phase difference sequences relevant with reference sequences length; And step S108-6, the two group phase difference sequences relevant with reference sequences length are averaged, and obtain the estimated frequency shift amount according to the length of reference sequences.

Step S108-2 may further comprise the steps: basis respectively ${{\widetilde{\mathrm{\φ}}}_1}^p\left(m\right)={{\mathrm{\θ}}_1}^{p+1}\left(m\right)-{{\mathrm{\θ}}_1}^p\left(m\right),$ With ${{\widetilde{\mathrm{\φ}}}_2}^p\left(m\right)={{\mathrm{\θ}}_2}^{p+1}\left(m\right)-{{\mathrm{\θ}}_2}^p\left(m\right)$ Calculate phase difference sequence corresponding to two data blocks, wherein, p=1,2 ..., P-1, m=1,2 ..., M, θ ₁ ^p(m) be phase difference sequence θ ₁(k) M+m value of (P-1) in, θ ₂ ^p(m) be phase difference sequence θ ₂(k) M+m value of (P-1) in, and $M=\frac{L}{P},$ Wherein, P is the number of reference sequences in the reference symbol.

Step S108-4 may further comprise the steps: basis respectively ${\mathrm{\φ}}_1\left(m\right)=\frac{1}{P-1}\underset{P=1}{\overset{P-1}{\mathrm{\Σ}}}{{\widetilde{\mathrm{\φ}}}_1}^P\left(m\right),$ With ${\mathrm{\φ}}_2\left(m\right)=\frac{1}{P-1}\underset{P=1}{\overset{P-1}{\mathrm{\Σ}}}{{\widetilde{\mathrm{\φ}}}_2}^P\left(m\right)$ Confirm the arithmetic mean of each item in two groups of phase difference sequences, thereby obtain the two group phase difference sequences relevant with reference sequences length, wherein, m=1,2 ..., M.

Step S108-6 may further comprise the steps: according to

Phase difference sequence corresponding to two data blocks is averaged, and according to

Confirm estimated frequency offset, wherein, N _FFTBe the length of the FFT of OFDM symbol, f is a subcarrier spacing.

This method is further comprising the steps of: utilize the estimated frequency shift amount to carry out Frequency Synchronization to the received signal, through the later estimated value that transmits of Frequency Synchronization Can be expressed as ${\tilde{s}}_k=R_k{e}^{2\mathrm{\π}{F}_{\mathrm{Offset}}t}=s_k{e}^{-2\mathrm{\π}(\mathrm{\Δ\; f}-F_{\mathrm{Offset}})t},$ Wherein, R _k=s _ke ^{-2 π Δ ft}The signal that expression receives, Δ f representes the frequency offset of transmitting-receiving two-end.

Fig. 2 illustrates being used for E-UTRA radio communication system up link frequency deviation estimating method and carrying out synchronous flow chart according to the frequency offset estimating value that said frequency deviation estimating method obtains according to first embodiment of the invention.With reference to Fig. 2, this embodiment may further comprise the steps:

Step S202, transmitting terminal construct reference symbol when framing becomes time slot, said reference symbol comprises Cyclic Prefix and reference sequences, after the framing by transmission antennas transmit.Wherein the position of reference symbol comprises 2 short blocks by the determining positions of short block SB in the structure of time slot that provides among Fig. 3 in a sub-frame, and the number of wherein long piece LB and protection interval T I are specifically provided according to different mode by the E-UTRA system.Wherein the structure of reference symbol is that P known reference sequence that repeats formed in the short block, is designated as Signal_Ref, and the front adds CP;

Step S204, receiving terminal be by antenna receiving signal, and the signal that will pass through the short block opposite position in the reception signal after the resume module such as receiver equalization according to gained time synchronized position intercepting respectively gets off (L is a short block length), is designated as r respectively _SB1And r _SB2And the reference symbol r of 2 short blocks that will receive _SB1And r _SB2Original reference symbol Signal_Ref during respectively with emission carries out phase place to be eliminated, and then its gained phase difference is noted, thereby is obtained 2 groups L phase information value θ ₁And θ ₂

Step S206, owing to form by P identical known array in the transmitting terminal reference symbol, with θ ₁And θ ₂In the corresponding phase value of adjacent 2 known arrays subtract each other, can obtain P-1 group phase difference sequence in each short block, average is got in its addition, promptly obtaining length is 2 groups of phase difference sequence φs relevant with known reference sequence length of L/P ₁And φ ₂

Step S208 is with the phase difference sequence φ of different short blocks ₁And φ ₂Average, its average is the phase difference between the estimated known reference sequence, can try to achieve the frequency shift (FS) of sending and receiving end from it, estimates thereby accomplish accurate frequency bias;

Step S210 utilizes estimated frequency shift (FS) of arriving to accomplish the Frequency Synchronization process.

Fig. 4 illustrates being used for E-UTRA radio communication system up link frequency deviation estimating method and carrying out synchronous flow chart according to the frequency offset estimating value that said frequency deviation estimating method obtains according to second embodiment of the invention.Among Fig. 4; The frequency deviation estimating method that is used for the E-UTRA radio communication system up link in the present embodiment with and carry out synchronous step according to the frequency offset estimating value that said frequency deviation estimating method obtains, respectively through the special repeated reference sequence symbol of transmitting terminal structure, the corresponding reception reference symbol of receiving terminal intercepting, utilize known reference sequence write down phase-shift information between adjacent known array, according to the phase-shift information between reference symbol structure smooth phase information, average different short blocks, according to the length of known array and phase-shift information is confirmed the frequency offset estimating value and accomplish module such as Frequency Synchronization according to the estimated frequency shift (FS) that obtains constitutes.These modules connect each other, wherein utilize in the reference symbol and short block between the repeatability of reference symbol carry out smoothly confirming final frequency offset estimating value and carry out the filtering of noise for phase pushing figure, finally directly obtain the accurate frequency bias estimation.

In the present embodiment, reference symbol structure is example with P=2, promptly comprises the known reference sequence of 2 repetitions in each short block, and this embodiment mainly may further comprise the steps:

Step S402, transmitting terminal construct reference symbol when framing becomes time slot, transmitting terminal is constructed reference symbol when framing becomes time slot, and said reference symbol comprises Cyclic Prefix and reference sequences, after the framing by transmission antennas transmit.Wherein the position of reference symbol comprises 2 short blocks by the determining positions of short block SB in the structure of time slot that provides among Fig. 1 in a sub-frame, and the structure of reference symbol is that the time domain waveform (oblique line part) of P=2 repetition is designated as Signal_Ref, and the front adds CP.Suppose channel h (τ, t) frequency shift (FS) of transmitting-receiving two-end is Δ f, supposes that simultaneously receiving terminal is ideal time with estimating that then receiving signal can be expressed as:

R _k＝s _ke ^-2πΔft (1)

Step S404 receives end by antenna receiving signal, and the signal that will pass through the short block opposite position in the reception signal after the resume module such as receiver equalization according to gained time synchronized position intercepting respectively gets off (L is a short block length), is designated as r respectively _SB1And r _SB2

Step S406 is with the reference symbol r of 2 short blocks that receive _SB1And r _SB2Original reference symbol Signal_Ref during respectively with emission carries out phase place to be eliminated, and then its gained phase difference is noted, thereby is obtained 2 groups L phase information value θ ₁(k) and θ ₂(k):

θ ₁(k)＝angle(s ^*(k)r ₁(k)) (2)

θ ₂(k)＝angle(s ^*(k)r ₂(k))

K=1 wherein, 2 ..., L.

Step S408 is divided into P identical part because length is the reference symbol of L, $M=\frac{L}{P},$ The corresponding phase value of adjacent 2 known reference sequence subtracts each other, and can obtain P-1 group phase difference sequence in each short block:

${\widetilde{\mathrm{\φ}}}_1^p\left(m\right)={\mathrm{\θ}}_1^{p+1}\left(m\right)-{\mathrm{\θ}}_1^p\left(m\right)---\left(3\right)$

${\widetilde{\mathrm{\φ}}}_2^p\left(m\right)={\mathrm{\θ}}_2^{p+1}\left(m\right)-{\mathrm{\θ}}_2^p\left(m\right)$

P=1 wherein, 2 ..., P-1, m=1,2 ..., M, θ _i ^p(m) be phase difference sequence θ _i, i=1, (P-1) M+m value in 2.

Arithmetic mean is got in its addition, and promptly obtaining length is 2 groups of phase difference sequence φs relevant with known reference sequence length of M ₁And φ ₂, as follows:

${\mathrm{\φ}}_1\left(m\right)=\frac{1}{P-1}\underset{p=1}{\overset{P-1}{\mathrm{\Σ}}}{{\widetilde{\mathrm{\φ}}}_1}^p\left(m\right)---\left(4\right)$

${\mathrm{\φ}}_2\left(m\right)=\frac{1}{P-1}\underset{p=1}{\overset{P-1}{\mathrm{\Σ}}}{{\widetilde{\mathrm{\φ}}}_2}^p\left(m\right)$

M=1 wherein, 2 ..., M.

Step S410 is with the phase difference sequence φ of different short blocks ₁(m) and φ ₂(m) average, its average is the phase difference between the estimated known reference sequence:

Because the length of known reference sequence does $M=\frac{L}{P},$ Then estimated frequency offset F _OffsetCan obtain by following formula:

N wherein _FFTBe the FFT length of OFDM symbol, f is a subcarrier spacing.

Step S412; Utilize estimated frequency shift (FS) of arriving to accomplish the Frequency Synchronization process, obtain being shown below through the estimated value

of the emission symbol after synchronous:

${\tilde{s}}_k=R_k{e}^{2\mathrm{\π}{F}_{\mathrm{offset}}t}=s_k{e}^{-2\mathrm{\π}(\mathrm{\Δf}-F_{\mathrm{offset}})t}---\left(7\right)$

Through embodiment of the present invention, be realization under the existing frame structure of E-UTRA with the frequency offset estimating scheme between set timing, secondly; Estimate that the frequency offset estimating error that obtains is little, and operand is less, in addition; Through adopting the multiple averaging algorithm, improved the correctness of this synchronized algorithm, and when guaranteeing frequency deviation method for synchronous precision; Operand is not significantly improved, and is beneficial to very much Project Realization.

The above is merely the preferred embodiments of the present invention, is not limited to the present invention, and for a person skilled in the art, the present invention can have various changes and variation.All within spirit of the present invention and principle, any modification of being done, be equal to replacement, improvement etc., all should be included within protection scope of the present invention.

Claims (5)

1. a frequency deviation estimating method that is used for radio communication system up link is characterized in that, may further comprise the steps:

Step S102, transmitting terminal is constructed reference symbol in the frame structure that transmits, and said transmitting is transmitted into receiving terminal;

Step S104, said receiving terminal extract said reference symbol from said signal after carrying out time synchronized to the received signal;

Step S106 will carry out bit comparison mutually with the said reference symbol of extracting at receiving terminal from the said reference symbol of said transmitting terminal, and comparative result will be recorded as the phase-shift information value; And

Step S108 confirms the frequency offset estimating value according to the length and the said phase-shift information value of the said said reference symbol that transmits;

Said reference symbol comprises a reference sequences or a plurality of identical reference sequences;

Said reference symbol is arranged in the data block of the said pre-position that transmits;

The quantity of said data block is two;

Said step S106 may further comprise the steps: the said reference symbol that will receive respectively with said transmitting in the original reference symbol carry out phase place and eliminate, the phase difference that record obtains obtains two groups of said phase-shift information value: θ ₁(k)=angle (s* (k) r ₁(k)), θ ₂(k)=angle (s* (k) r ₂(k)), wherein, k=1,2 ..., L, L are the length of said reference sequences, r ₁(k), r ₂(k) represent respectively corresponding to the said reference symbol in two said data blocks;

Said step S108 may further comprise the steps:

Step S108-2 will subtract each other corresponding to the said phase-shift information value of two adjacent in the same said data block said reference sequences and obtain two groups of phase difference sequences;

Step S108-4 confirms the arithmetic mean of each item in said two groups of phase difference sequences to obtain the two group phase difference sequences relevant with said reference sequences length; And

Step S108-6, the two group phase difference sequences relevant to said and said reference sequences length average, and obtain the estimated frequency shift amount according to the length of said reference sequences.

2. method according to claim 1 is characterized in that, said step S108-2 may further comprise the steps: basis respectively With

Calculate said phase difference sequence corresponding to two said data blocks, wherein, p=1,2 ..., P-1, m=1,2 ..., M, θ ₁ ^p(m) be phase difference sequence θ ₁(k) M+m value of (P-1) in, θ ₂ ^p(m) be phase difference sequence θ ₂(k) M+m value of (P-1) in, and

Wherein, P is the number of reference sequences described in the said reference symbol.

3. method according to claim 1; It is characterized in that; Said step S108-4 may further comprise the steps: the arithmetic mean of confirming each item in said two groups of phase difference sequences respectively according to

and ; Thereby obtain the two group phase difference sequences relevant with said reference sequences length; Wherein, M=1; 2 ..., M.

4. method according to claim 1 is characterized in that, said step S108-6 may further comprise the steps: according to Said phase difference sequence corresponding to two said data blocks is averaged, and according to

Confirm estimated frequency offset, wherein, N _FFTBe the length of the FFT of OFDM symbol, f is a subcarrier spacing.

5. method according to claim 4 is characterized in that, and is further comprising the steps of: utilize said estimated frequency shift amount that the said signal that receives is carried out Frequency Synchronization, through the later said estimated value that transmits of Frequency Synchronization

Can be expressed as

Wherein, R _k=s _ke ^{-2 π Δ ft}Represent the said signal that receives, Δ f representes the frequency offset of transmitting-receiving two-end.

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