CN102413079A - Initial fraction frequency offset estimation method used in downlink of 3<rd> generation partnership project long term evolution (3GPP-LTE) system - Google Patents

Initial fraction frequency offset estimation method used in downlink of 3<rd> generation partnership project long term evolution (3GPP-LTE) system Download PDF

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CN102413079A
CN102413079A CN201110354857XA CN201110354857A CN102413079A CN 102413079 A CN102413079 A CN 102413079A CN 201110354857X A CN201110354857X A CN 201110354857XA CN 201110354857 A CN201110354857 A CN 201110354857A CN 102413079 A CN102413079 A CN 102413079A
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pss
sequence
frequency offset
frequency deviation
3gpp
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CN102413079B (en
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王丰
朱宇
张俊博
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Fudan University
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Fudan University
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Abstract

The invention belongs to the broadband wireless mobile communication technology field and discloses an initial fraction frequency offset estimation method used in downlink of a 3<rd> generation partnership project long term evolution (3GPP-LTE) system. The method comprises the following steps: acquiring a primary synchronization channel (SCH) signal (PSS) timing position of a reception baseband digit signal sequence and a cell identification group number; using two methods to carry out frequency offset estimation so as to acquire a candidate set of an initial fraction frequency offset value, wherein one method is to carry out a maximum likelihood (ML) algorithm based on a regular cycle prefix (CP) and the other method is to use the received PSS sequence and a local detected PSS sequence to perform correlation accumulation; in different SNR areas of the reception signal, through setting a frequency offset threshold, determining the final initial fraction frequency offset estimation value from the candidate set. In the invention, operation is simple. Compared to individually using PSS cross correlation and the ML algorithm based on the CP, using the method of the invention, mean square error performance is good.

Description

3GPP-LTE system down link initial score frequency deviation estimating method
Technical field
The invention belongs to the wideband wireless mobile communication technical field, be specifically related to third generation partner program Long Term Evolution (3 RdGeneration Partnership Project Long Term Evolution, 3GPP-LTE) the initial score frequency deviation estimating method in the downlink synchronization process.
Background technology
Simultaneous techniques is a very important wireless mobile telecommunication technology, and synchronizing process mainly comprises time timing and Frequency Synchronization, is that any communication system all needs the primary process of accomplishing synchronously.In the 3G epoch of wireless mobile communications, there is very high requirement in system to synchronizing process, and the net synchronization capability direct relation quality and the two-forty of voice in the radio communication, data service, the digital multimedia application service of low delay.Yet, in the wireless environment of reality, stop, factor such as shade, multipath fading that signal has been caused very big interference, and this has also proposed stern challenge to simultaneous techniques.
Third generation partner program (3 RdGeneration partnership project 3GPP) will have begun Long Term Evolution (long term evolution, LTE) project in the end of the year 2004.The first step of the synchronizing process of 3GPP-LTE is to carry out downlink synchronization; It is Cell searching; As user (user equipment; UE) switch or need carry out Cell searching when initially inserting; UE need carry out synchronizing channel (synchronization channel; SCH) input, (primary SCH signal is PSS) with auxiliary synchronization channel signal (secondary SCH to be specially the primary synchronization channel signal; SSS) detect; To obtain numbering
Figure 314721DEST_PATH_IMAGE002
in cell ID group number and the cell ID group, read the broadcast channel information of this sub-district, in this process; UE need estimate separately timing error and original carrier frequency deviation (carrier frequent offset, CFO).The air interface of 3GPP-LTE system adopts the OFDM access at down link, and (this technology is with OFDM (orthogonal frequency division multiplexing for orthogonal frequency division multiple access, OFDMA) technology; OFDM) be the basis; Through whole channel being divided into a plurality of mutually orthogonal subchannels, the influence that can resist frequency-selective channel well can obtain the very high availability of frequency spectrum; But; OFDM is very high to synchronous requirement, and especially (carrier frequent offset CFO) compares sensitivity to carrier wave frequency deviation.Therefore in the PSS testing process, initial CFO estimates just to become the key factor that influences the LTE net synchronization capability.
The existing CFO algorithm for estimating that is used for ofdm system mainly is divided into pilot tone auxiliary (pilot aided, algorithm for estimating PA) and blind estimation (blind estimation, BE) algorithm.Specifically in the LTE system; A kind of algorithm that is based on pilot tone mainly is to utilize the cross-correlation that receives PSS time domain sequences and local PSS sequence, obtains a cross-correlation sequence, and the cross-correlation sequence is divided into two sections; Summation adds up respectively; Utilize the phase difference of two accumulated values to carry out the CFO estimation, the method for PSS cross-correlation has made full use of the good correlation properties of PSS sequence, and estimated performance is better; Another kind is an architectural feature of utilizing the OFDM symbol, and promptly (cyclic prefix CP) is the copy of OFDM tail data to Cyclic Prefix; Based on maximum likelihood (maximum likelihood; ML) criterion is utilized its autocorrelative phase place to carry out CFO and is estimated, can only estimate the frequency deviation of a number of sub-carrier at interval based on the ML method of CP; Estimated performance is subject to the influence of multipath channel in addition, but the ML method that is based on CP can realize in a plurality of OFDM symbol times.When carrying out the mark frequency offset estimating; In general, the frequency offset estimation accuracy of the method for PSS cross-correlation is superior to based on the estimation of the ML method of CP well, still; Under less frequency deviation region and high state of signal-to-noise, can be superior to the method for PSS cross-correlation based on the precision of the ML method of CP.S-SCH detection method with low complex degree.But prior LTE system initial score frequency deviation estimating method focuses mostly in independent employing PA algorithm or BE algorithm, lacks the initial score frequency deviation estimating method that can effectively unite PA algorithm and BE algorithm.
Summary of the invention
The objective of the invention is to propose the initial score frequency deviation estimating method in the downlink synchronization of a kind of 3GPP-LTE of being applicable to system, can effectively unite the PSS cross-correlation method and based on the ML method of CP.
The present invention proposes to be applicable to the initial score frequency deviation estimating method in the downlink synchronization of 3GPP-LTE system, and the baseband digital signal time domain sequences to receiving the steps include:
Step 1:Obtain the master sync signal PSS timing position and the interior numbering of cell ID group of receiving sequence
Step 2:To the PSS time domain sequences that obtains receiving through narrow band filter, according to what detect
Figure 979237DEST_PATH_IMAGE002
Produce local PSS time-domain signal; The first half and the local PSS sequence first half conjugate multiplication of the PSS sequence that receives are added up; The latter half of the PSS sequence that receives and the latter half conjugate multiplication of local PSS sequence add up; Calculate the phase difference of two conjugate multiplication accumulated values, obtain the initial score frequency deviation
Figure 201110354857X100002DEST_PATH_IMAGE003
Step 3:To without the receiving sequence of crossing narrow band filter, adopt ML method to obtain the initial score frequency offset estimating based on CP
Figure 430159DEST_PATH_IMAGE004
Step 4:Carry out the initial score frequency offset estimating, by above-mentioned steps, system has obtained Candidate Set , note reception signal SNRFor
Figure 692644DEST_PATH_IMAGE006
, set one SNRThreshold value
Figure 201110354857X100002DEST_PATH_IMAGE007
, under the low signal-to-noise ratio situation, when the normalization frequency deviation region is [0.5.0.5], be lower than the frequency offset estimating performance of the cross-correlation method of utilizing the PSS sampled signal based on the frequency offset estimating performance of the ML algorithm of CP, so low SNRThe frequency offset estimating based on PSS is selected in the zone
Figure 859183DEST_PATH_IMAGE003
, through emulation platform test, appropriate threshold
Figure 15358DEST_PATH_IMAGE007
Scope is 0 ~ 5 dB, that is, when
Figure 625462DEST_PATH_IMAGE008
The time, the initial frequency deviation value
Figure 201110354857X100002DEST_PATH_IMAGE009
, when
Figure 296615DEST_PATH_IMAGE010
The time, through setting the frequency deviation threshold value , wherein
Figure 283156DEST_PATH_IMAGE012
, The zone when less frequency deviation exists, is superior to utilizing the estimated performance of PSS cross-correlation method, threshold value based on the estimated performance of the ML method of CP
Figure 137160DEST_PATH_IMAGE011
Concrete value count with CP and PSS signals sampling and to transmit radio channel state relevant, in practical implementation, threshold value With
Figure 741634DEST_PATH_IMAGE011
Setting, be based on employing Step 2With Step 3The comparison of the frequency offset estimating performance of two kinds of methods, when The time, the initial frequency deviation value
Figure 824307DEST_PATH_IMAGE009
, when
Figure 470052DEST_PATH_IMAGE010
The time, if
Figure 201110354857X100002DEST_PATH_IMAGE013
The time,
Figure 532817DEST_PATH_IMAGE014
, otherwise,
Figure 518091DEST_PATH_IMAGE009
Thereby, obtain final initial score frequency offset estimating
Figure 201110354857X100002DEST_PATH_IMAGE015
Concrete testing process is as shown in Figure 4.Do further to introduce in the face of the concrete calculating of each step down:
Step 1:Obtain the master sync signal PSS timing position and the interior numbering of cell ID group that receive the baseband digital signal sequence , it is following step by step:
Step by step 1.1: to received signal carry out time-domain sampling, obtain receiving sequence through narrowband low-pass filter, according to the time synchronization information that the time synchronized module is confirmed, obtain the thick regularly synchronized result of PSS, note receiving terminal PSS time-domain sampling sequence does
Figure 773940DEST_PATH_IMAGE016
:
Figure 201110354857X100002DEST_PATH_IMAGE017
，
Wherein,
Figure 889663DEST_PATH_IMAGE018
Represent normalized carrier wave frequency deviation (carrier frequency offset, CFO),
Figure 201110354857X100002DEST_PATH_IMAGE019
The time domain form of the main synchronous PSS sequence of expression,
Figure 604810DEST_PATH_IMAGE020
Expression FFT FFT counts, when the LTE bandwidth is set to 20MHz,
Figure 201110354857X100002DEST_PATH_IMAGE021
,
Figure 898519DEST_PATH_IMAGE022
(
Figure 201110354857X100002DEST_PATH_IMAGE023
) the expression channel impulse response, in LTE channel simulator model, L=8,
Figure 66326DEST_PATH_IMAGE024
The multiple Gaussian noise of expression additivity, its power spectral density does
Step by step 1.2: local PSS frequency domain sequence transforms to the PSS sequence of time domain through invert fast fourier transformation IFFT , ,
Figure 555393DEST_PATH_IMAGE028
, with receiving sequence
Figure 206955DEST_PATH_IMAGE016
With local PSS sequence , obtain three relevant episode, get the corresponding PSS of maximum related value, promptly
Figure 201110354857X100002DEST_PATH_IMAGE029
，
Wherein, * represent conjugate operation therefore, confirm numbering
Figure 884689DEST_PATH_IMAGE002
in the cell ID group according to detected value
Figure 522846DEST_PATH_IMAGE030
.
Step 2:The PSS sampled signal that arrives to local reception
Figure 972731DEST_PATH_IMAGE016
With detect
Figure 302081DEST_PATH_IMAGE002
It is relevant that pairing local PSS time domain sequences is carried out pointwise, obtains a correlated series, and then the correlated series that obtains being divided equally is two sections, obtains frequency deviation according to this phase difference of two sections
Figure 235402DEST_PATH_IMAGE003
Step by step 2.1: according to the 3GPP-LTE agreement, the frequency domain sequence of master sync signal PSS is to adopt the Zadoff-Chu sequence, and numbering in the cell set
Figure 717330DEST_PATH_IMAGE002
One by one corresponding to the radical exponent of Zadoff-Chu sequence , through
Figure 38590DEST_PATH_IMAGE020
Point IFFT, conversion obtains the PSS time domain sequences.
According to 3GPP TS 36.211 V8.5.0 agreements, 3GPP LTE adopts be 62 long Zadoff-Chu sequences as the primary synchronization channel signal, sequence signature is:
Figure 340389DEST_PATH_IMAGE032
，
Wherein
Figure 342980DEST_PATH_IMAGE031
is called the radical exponent of Zadoff-Chu sequence; Value is { 25; 29; 34}; Correspond respectively to sub-district in the LTE system represent to organize the value of interior numbering
Figure 928682DEST_PATH_IMAGE002
0,1,2}.
Note exists Step 1Obtain
Figure 894278DEST_PATH_IMAGE002
Corresponding Zadoff-Chu sequence radical exponent very
Figure 201110354857X100002DEST_PATH_IMAGE033
, obtain local PSS frequency domain sequence ,
Figure 201110354857X100002DEST_PATH_IMAGE035
, according to the mapping relations of PSS sequence and subcarrier, through NPoint IFFT conversion obtains local PSS time domain sequences
Figure 551972DEST_PATH_IMAGE036
,
Figure 929864DEST_PATH_IMAGE028
Step by step 2.2: will receive
Figure 592927DEST_PATH_IMAGE016
With Step by step 2.1Obtain
Figure 56269DEST_PATH_IMAGE036
It is relevant to carry out pointwise, obtains a correlated series
Figure 201110354857X100002DEST_PATH_IMAGE037
,
Figure 213712DEST_PATH_IMAGE028
, that is:
Where
Figure DEST_PATH_IMAGE039
and
Figure 93123DEST_PATH_IMAGE040
denote the interference term and noise term.
Step by step 2.3: with above-mentioned correlated series
Figure 309341DEST_PATH_IMAGE037
Be divided into two sections, utilize the phase difference between two sections, estimate corresponding frequency deviation value.
Influence for further level and smooth distracter and noise item; Simultaneously in order to utilize the good autocorrelation performance of PSS sequence;
Figure 254163DEST_PATH_IMAGE037
is divided into isometric two sections with correlated series; Each segment data is taked the method that adds up, obtains
Figure DEST_PATH_IMAGE041
and
Figure 419697DEST_PATH_IMAGE042
:
Figure DEST_PATH_IMAGE043
，
Figure 158982DEST_PATH_IMAGE044
。
If do not consider distracter and noise item, then
Figure DEST_PATH_IMAGE045
，
Observe following formula; Can see;
Figure 409966DEST_PATH_IMAGE041
and exists phase difference; Therefore; Relevant through
Figure 365470DEST_PATH_IMAGE041
carried out conjugation with
Figure 291969DEST_PATH_IMAGE042
; Can obtain the frequency offset estimating value; Be designated as
Figure 217199DEST_PATH_IMAGE003
, that is:
，
Wherein, AngleThe phase angle computing is asked in (.) expression.
Step 3: (cyclic prefix, method CP) is estimated the initial score frequency deviation value according to Cyclic Prefix.After preliminary timing through synchronizing signal PSS; Note
Figure DEST_PATH_IMAGE047
is without the receiving sequence of crossing narrow-band filtering, order:
Figure 643950DEST_PATH_IMAGE048
,
Wherein GThe length of expression CP adopts the maximum likelihood algorithm based on CP, can get the frequency offset estimating value, and note is done
Figure 928300DEST_PATH_IMAGE004
, promptly
Figure DEST_PATH_IMAGE049
Step 4:Confirm final initial score frequency deviation
Figure 950614DEST_PATH_IMAGE015
Through Step 2With Step 3The frequency offset estimating value that obtains is formed Candidate Set
Figure 978613DEST_PATH_IMAGE005
, note reception signal SNRFor
Figure 222513DEST_PATH_IMAGE006
, relatively Step 2With Step 3The frequency offset estimating MSE performance of corresponding two kinds of methods is set one SNRThreshold value
Figure 677765DEST_PATH_IMAGE007
, when The time, the initial frequency deviation value
Figure 19064DEST_PATH_IMAGE009
, when
Figure 55154DEST_PATH_IMAGE010
The time, through setting the frequency deviation threshold value
Figure 494356DEST_PATH_IMAGE011
, wherein
Figure 615896DEST_PATH_IMAGE012
, if
Figure 48014DEST_PATH_IMAGE013
The time, , otherwise,
Figure 814293DEST_PATH_IMAGE009
Thereby, obtain final initial score frequency offset estimating
Figure 423129DEST_PATH_IMAGE015
So far, initial score frequency deviation estimating method of the present invention is accomplished.
The characteristics of the inventive method:
(1) the present invention has united based on the PSS cross-correlation method of estimation of pilot tone with based on the ML maximum Likelihood of CP, has obtained frequency offset estimating least mean-square error (MSE) performance preferably.
(2) the present invention is provided with frequency offset estimating value threshold value through the SNR zone that receives signal at some, and existing popular this frequency deviation estimating method is joined together, and therefore, the selection of threshold value will be a key factor.
(3) the present invention is applicable to FDD and tdd frame structure, than under the condition of severe, still can keep satisfied MSE performance in noise and channel ratio.
Description of drawings
Fig. 1 is a FDD wireless frame structure sketch map in the 3GPP LTE system.
Fig. 2 is a TDD wireless frame structure sketch map in the 3GPP LTE system.
Fig. 3 is the mapping graph between synchronous channel SCH and the subcarrier in the 3GPP LTE system.
Fig. 4 is a detection method schematic flow sheet of the present invention.
Fig. 5 is applied to the MSE performance simulation result of experimental example 1 among the embodiment for the present invention.
Embodiment
Below will a kind of 3GPP of being used for LTE system down link initial score frequency deviation estimating method proposed by the invention be set forth in detail with reference to accompanying drawing and specific embodiment.
The invention provides the method for the down link initial score frequency offset estimating of a kind of 3GPP of being used for LTE system, basic principle is to utilize the ML principle earlier, and it is relevant to adopt the CP and the repeatability of initial data to carry out, and estimates frequency shift (FS)
Figure 393359DEST_PATH_IMAGE004
, utilize reception signal and local PSS time domain sequences to carry out cross-correlation again, estimate frequency deviation
Figure 404041DEST_PATH_IMAGE003
, obtain Candidate Set this moment
Figure 185046DEST_PATH_IMAGE050
, and then divide the reception signal SNRThe zone is through being provided with the frequency deviation threshold value
Figure 281178DEST_PATH_IMAGE011
, selective system frequency offset estimating value from Candidate Set.
Consider that is realized a third generation partner program Long Term Evolution (3 RdGeneration Partnership Project Long Term Evolution, 3GPP LTE) downlink system, 3GPP has defined the frame structure of FDD and TDD in the current LTE standard; FDD is different duplex modes with TDD, but a lot of similarities are arranged on frame structure, and a radio frames time cycle is 10 ms; The time slot that comprises 20 0.5 ms, when using conventional CP, each time slot comprises 7 OFDM symbols; When using expansion CP, comprise 6 OFDM symbols, when concrete the realization; CP is the copy of initial data afterbody part data, can avoid the phase mutual interference between useful data, can resist the influence of multipath effectively.
Fig. 1 and Fig. 2 have provided the sketch map of FDD and tdd frame structure.In FDD frame structure shown in Figure 1, PSS is positioned at time slot #0 and time slot #10, and is arranged on last 1 OFDM symbol of these time slots, and SSS is positioned on the second-to-last OFDM symbol of PSS place time slot.Tdd frame structure shown in Figure 2, PSS is positioned at time slot #2 and #12, and to be arranged in these time slot sequence numbers be that SSS is positioned at time slot #1 and time slot #11, and is arranged in last OFDM symbol of these time slots on 2 the OFDM symbol.Fig. 3 has shown in FDD frame and the tdd frame structure that PSS and SSS are positioned near 72 number of sub-carrier the DC component.
Fig. 4 has provided the method for estimation that is used for 3GPP LTE system down link initial score frequency deviation, with reference to accompanying drawing, below with the operating process of process in detail.
Based on the ML algorithm of CP, carry out auto-correlation to the baseband digital signal that the receives OFDM symbol of delaying time, in one embodiment, note , wherein nExpression time domain sequence number, Be the time domain data of baseband digital signal, GThe length of expression accumulator, NThe sampling of an OFDM of expression is counted, and in the LTE of 20MHz system, can be set to conventional CP length 144 or littler numerical value, N=2048, based on correlation PPhase place, carry out fractional frequency and estimate, in an embodiment, adopt formula
Figure 998915DEST_PATH_IMAGE052
Estimate the frequency shift (FS) of each sampled point, can average, be used to significantly improve through a plurality of OFDM symbols
Figure 200089DEST_PATH_IMAGE004
Estimated accuracy.
The baseband digital signal that receives is carried out narrow-band low pass filtering.The PSS signal is positioned near 72 number of sub-carrier the DC component, carries out LPF and can not exert an influence to PSS, and in one embodiment, narrowband low-pass filter can keep near 62 number of sub-carrier data the DC component, i.e. PSS sequence.To carry out cross-correlation through the baseband digital signal of over-sampling and local candidate's PSS signal.Baseband signal after the note sampling does
Figure 517938DEST_PATH_IMAGE016
, local candidate's PSS time domain sequences , wherein
Figure 831556DEST_PATH_IMAGE054
Interior numbering is represented to organize in the expression sub-district,
Figure 203632DEST_PATH_IMAGE027
, nExpression time domain sequences sequence number,
Figure 8776DEST_PATH_IMAGE028
, NThe sampling number of expression OFDM symbol.With time domain sequences and local PSS sequence
Figure 715012DEST_PATH_IMAGE026
; Obtain three relevant episode; Get the corresponding PSS of maximum related value, promptly
Figure DEST_PATH_IMAGE055
，
Wherein, * representes conjugate operation.Therefore, confirm numbering
Figure 640778DEST_PATH_IMAGE002
in the cell ID group according to detected value
Figure 257989DEST_PATH_IMAGE030
.
To local reception to PSS time domain sequences
Figure 232296DEST_PATH_IMAGE016
and the pairing local PSS time domain sequences of detected value
Figure 906040DEST_PATH_IMAGE056
to carry out pointwise relevant; Obtain a correlated series, wherein correspondence and
Figure 956352DEST_PATH_IMAGE002
that detect.In specific embodiment; Note correlated series
Figure 770725DEST_PATH_IMAGE037
;
Figure 406237DEST_PATH_IMAGE028
Where
Figure 735587DEST_PATH_IMAGE039
and
Figure 934487DEST_PATH_IMAGE040
denote the interference term and noise term.
Figure 416415DEST_PATH_IMAGE037
is divided into two sections with above-mentioned correlated series; Obtain
Figure 409779DEST_PATH_IMAGE041
and
Figure 226425DEST_PATH_IMAGE042
, promptly
，
Figure DEST_PATH_IMAGE059
。
If do not consider distracter and noise item, then
Figure 627768DEST_PATH_IMAGE060
，
Through
Figure 605082DEST_PATH_IMAGE041
and
Figure 846707DEST_PATH_IMAGE042
being carried out conjugate multiplication, i.e.
Figure 449727DEST_PATH_IMAGE046
.
So far, the LTE system has obtained the frequency deviation Candidate Set
Figure 827619DEST_PATH_IMAGE005
, the note receiving baseband signal
Figure 241414DEST_PATH_IMAGE047
SNRFor
Figure 704756DEST_PATH_IMAGE006
, set one SNRThreshold value
Figure 111467DEST_PATH_IMAGE007
, when The time, the initial frequency deviation value
Figure 928561DEST_PATH_IMAGE009
, when
Figure 879200DEST_PATH_IMAGE010
The time, through setting the frequency deviation threshold value , wherein
Figure 989555DEST_PATH_IMAGE012
, if
Figure 932103DEST_PATH_IMAGE013
The time,
Figure 432355DEST_PATH_IMAGE014
, otherwise, , in simulation example, get
Figure DEST_PATH_IMAGE061
DB,
Figure 138591DEST_PATH_IMAGE062
Thereby, obtain system's initial score frequency offset estimating
Figure 314357DEST_PATH_IMAGE015
In order to verify the validity of this patent detection method, Computer Simulation has been carried out in following experiment.
Experimental example 1:Under multipath channel, initial score frequency offset estimating MSE performance of the present invention.
Consider one 8 footpath rayleigh fading channel model, wherein multipath channel is defined as the frequency selective fading of exponential power delay profile, and time-delay equals the sampling period between every footpath, and the average power in each footpath does
Figure DEST_PATH_IMAGE063
，
In emulation, get
Figure 52637DEST_PATH_IMAGE064
.
Fig. 5 has shown under the 8 footpath channels; In 3000 times the circulation emulation; The performance curve that the normalization MSE of frequency offset estimating algorithm changes with average received signal to noise ratio
Figure DEST_PATH_IMAGE065
, normalization MSE is defined as:
Figure 339262DEST_PATH_IMAGE066
。
Wherein,
Figure DEST_PATH_IMAGE067
expression Monte Carlo simulation times; During the inferior emulation of
Figure 479387DEST_PATH_IMAGE068
expression ; System's normalization mark frequency deviation value, frequency deviation estimated value during the inferior emulation of
Figure 560476DEST_PATH_IMAGE070
expression .On simulation parameter is provided with,
Figure 814051DEST_PATH_IMAGE068
Obey evenly distribution, receiving baseband signal in interval [0.5,0.5] SNRThreshold value is set to
Figure DEST_PATH_IMAGE071
0 dB, the frequency offset estimating threshold value is set to
Figure 57950DEST_PATH_IMAGE072
0.3 the sampling number of an OFDM symbol does N=2048, the sampling number of CP does G=144.In Fig. 5; The frequency deviation estimating method of PSS cross-correlation is taked in " PSS corr. " expression; " CP based " expression is based on the ML method of CP; The method of estimation of " Proposed " expression this patent, can obtain: compare based on the ML algorithm of CP and the method for PSS cross-correlation, this method has MSE performance preferably.

Claims (4)

1. one kind is applicable to 3GPP-LTE system down link initial score frequency deviation estimating method, it is characterized in that concrete steps are following: to the baseband digital signal time domain sequences that receives,
Step 1:Obtain the master sync signal PSS timing position and the interior numbering of cell ID group of receiving sequence
Figure 799511DEST_PATH_IMAGE001
Step 2:To the PSS time domain sequences that obtains receiving through narrow band filter, according to what detect
Figure 716652DEST_PATH_IMAGE001
Produce local PSS time-domain signal; The first half and the local PSS sequence first half conjugate multiplication of the PSS sequence that receives are added up; The latter half of the PSS sequence that receives and the latter half conjugate multiplication of local PSS sequence add up; Calculate the phase difference of two conjugate multiplication accumulated values, obtain the initial score frequency deviation
Step 3:To without the receiving sequence of crossing narrow band filter, adopt ML method to obtain the initial score frequency offset estimating based on CP
Figure 704647DEST_PATH_IMAGE003
Step 4:Carry out the initial score frequency offset estimating,, obtain Candidate Set by above-mentioned steps
Figure 581336DEST_PATH_IMAGE004
, note reception signal SNRFor
Figure 403799DEST_PATH_IMAGE005
, set one SNRThreshold value
Figure 483882DEST_PATH_IMAGE006
, when The time, the initial frequency deviation value , when
Figure 220390DEST_PATH_IMAGE009
The time, through setting the frequency deviation threshold value , wherein
Figure 774049DEST_PATH_IMAGE011
, if The time,
Figure 602644DEST_PATH_IMAGE013
, otherwise,
Figure 844270DEST_PATH_IMAGE008
Thereby, obtain final initial score frequency offset estimating
Figure 944161DEST_PATH_IMAGE014
2. the 3GPP-LTE system down link initial score frequency deviation estimating method that is applicable to according to claim 1 is characterized in that Step 1Obtain the master sync signal PSS timing position and the interior numbering of cell ID group that receive the baseband digital signal sequence
Figure 649949DEST_PATH_IMAGE001
, it is following step by step:
Step by step 1.1: to receiving the time-domain sampling that carries out of baseband digital signal, obtain receiving sequence through narrowband low-pass filter, according to the time synchronization information that the time synchronized module is confirmed, obtain the thick regularly synchronized result of PSS, the equivalent baseband sampling sequence of note receiving terminal PSS time domain does
Figure 985116DEST_PATH_IMAGE015
:
Figure 527087DEST_PATH_IMAGE016
，
Wherein,
Figure 605901DEST_PATH_IMAGE017
representes normalized carrier wave frequency deviation; The time domain form of the main synchronous PSS sequence of
Figure 166195DEST_PATH_IMAGE018
expression;
Figure 750892DEST_PATH_IMAGE019
expression FFT FFT counts;
Figure 701530DEST_PATH_IMAGE020
representes channel impulse response;
Figure 646352DEST_PATH_IMAGE021
; The multiple Gaussian noise of
Figure 998836DEST_PATH_IMAGE022
expression additivity, its power spectral density is
Figure 754434DEST_PATH_IMAGE023
;
Step by step 1.2: local PSS frequency domain sequence transforms to the PSS sequence of time domain through invert fast fourier transformation IFFT
Figure 192368DEST_PATH_IMAGE024
,
Figure 675302DEST_PATH_IMAGE025
,
Figure 147872DEST_PATH_IMAGE026
, with receiving sequence
Figure 74371DEST_PATH_IMAGE015
With local PSS sequence
Figure 61918DEST_PATH_IMAGE024
, obtain three relevant episode, get the corresponding PSS of maximum related value, that is:
Figure 286226DEST_PATH_IMAGE027
，
Wherein, * represent conjugate operation, confirm numbering
Figure 445123DEST_PATH_IMAGE029
in the cell ID group according to detected value .
3. the 3GPP-LTE system down link initial score frequency deviation estimating method that is applicable to according to claim 2 is characterized in that Step 2Calculate initial score frequency deviation frequency deviation Following step by step;
Step by step 2.1: according to the 3GPP-LTE agreement, the frequency domain sequence of master sync signal PSS adopts the Zadoff-Chu sequence, numbering in the cell set One by one corresponding to the radical exponent of Zadoff-Chu sequence , through
Figure 132271DEST_PATH_IMAGE019
Point IFFT, conversion obtains the PSS time domain sequences;
According to 3GPP TS 36.211 V8.5.0 agreements, 3GPP LTE adopts the Zadoff-Chu sequence of 62 length as the primary synchronization channel signal, and sequence signature is:
Figure 94410DEST_PATH_IMAGE031
，
Wherein,
Figure 660521DEST_PATH_IMAGE030
is called the radical exponent of Zadoff-Chu sequence; Value is { 25; 29; 34}; Correspond respectively to sub-district in the LTE system represent to organize the value of interior numbering
Figure 775239DEST_PATH_IMAGE001
0,1,2};
Note exists Step 1Obtain
Figure 198130DEST_PATH_IMAGE001
Corresponding Zadoff-Chu sequence radical exponent very
Figure 585249DEST_PATH_IMAGE032
, obtain local PSS frequency domain sequence
Figure 768100DEST_PATH_IMAGE033
,
Figure 658695DEST_PATH_IMAGE034
, according to the mapping relations of PSS sequence and subcarrier, through NPoint IFFT conversion obtains local PSS time domain sequences
Figure 518067DEST_PATH_IMAGE035
,
Figure 126903DEST_PATH_IMAGE026
Step by step 2.2: will receive
Figure 113444DEST_PATH_IMAGE015
With Step by step 2.1Obtain
Figure 124126DEST_PATH_IMAGE035
It is relevant to carry out pointwise, obtains a correlated series
Figure 154399DEST_PATH_IMAGE036
,
Figure 250531DEST_PATH_IMAGE026
, that is:
Figure 775184DEST_PATH_IMAGE038
Wherein, and
Figure 841546DEST_PATH_IMAGE040
representes distracter and noise item respectively;
Step by step 2.3: with above-mentioned correlated series Be divided into two sections, utilize the phase difference between two sections, estimate corresponding frequency deviation value;
Figure 550056DEST_PATH_IMAGE036
is divided into isometric two sections with correlated series; Each segment data is taked the method that adds up, obtains
Figure 535330DEST_PATH_IMAGE041
and :
Figure 791179DEST_PATH_IMAGE043
，
Figure 719951DEST_PATH_IMAGE044
?；
Perhaps do not consider distracter and noise item, then:
Figure 372781DEST_PATH_IMAGE045
，
Relevant through
Figure 853441DEST_PATH_IMAGE041
carried out conjugation with
Figure 208199DEST_PATH_IMAGE042
; Obtain the frequency offset estimating value; Be designated as
Figure 878345DEST_PATH_IMAGE002
, that is:
，
Wherein, AngleThe phase angle computing is asked in (.) expression.
4. the 3GPP-LTE system down link initial score frequency deviation estimating method that is applicable to according to claim 3 is characterized in that Step 3The initial score frequency offset estimating
Figure 286510DEST_PATH_IMAGE003
Be step by step: the method according to Cyclic Prefix (CP) is estimated the initial score frequency deviation value, through synchronizing signal PSS preliminary regularly after, note Be receiving sequence, order without the mistake narrow-band filtering:
Figure 528366DEST_PATH_IMAGE048
,
Wherein GThe length of expression CP adopts the maximum likelihood algorithm based on CP, gets the frequency offset estimating value, and note is done
Figure 77159DEST_PATH_IMAGE003
, promptly
Figure 227518DEST_PATH_IMAGE049
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Cited By (20)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN103259755A (en) * 2013-04-08 2013-08-21 东南大学 Main synchronization sequence design method for global covering multi-beam satellite LTE
CN103312654A (en) * 2013-05-23 2013-09-18 东南大学 Master synchronization sequence detection method for full-domain coverage multi-beam satellite long term evolution (LTE)
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CN103780527A (en) * 2012-10-18 2014-05-07 晨星软件研发(深圳)有限公司 Frequency offset estimation method of multicarrier communication system, and correlation apparatus
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WO2015149199A1 (en) * 2014-04-03 2015-10-08 中兴通讯股份有限公司 Differential phase-based frequency offset estimation method and apparatus
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CN109328452A (en) * 2016-06-29 2019-02-12 瑞典爱立信有限公司 Signal detection mode it is adaptively selected
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Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN1705302A (en) * 2004-05-27 2005-12-07 华为技术有限公司 OFDM time and frequency synchronization method
US20090252246A1 (en) * 2008-04-03 2009-10-08 Samsung Electronics Co., Ltd. Receiving apparatus and method for maximum likelihood in a single carrier system
CN101827052A (en) * 2010-04-14 2010-09-08 中国科学院计算技术研究所 Method and device for time synchronization and frequency synchronization of LTE system
US20100246730A1 (en) * 2009-03-30 2010-09-30 Tareq Al-Naffouri Cyclic prefix-based enhanced data recovery method

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN1705302A (en) * 2004-05-27 2005-12-07 华为技术有限公司 OFDM time and frequency synchronization method
US20090252246A1 (en) * 2008-04-03 2009-10-08 Samsung Electronics Co., Ltd. Receiving apparatus and method for maximum likelihood in a single carrier system
US20100246730A1 (en) * 2009-03-30 2010-09-30 Tareq Al-Naffouri Cyclic prefix-based enhanced data recovery method
CN101827052A (en) * 2010-04-14 2010-09-08 中国科学院计算技术研究所 Method and device for time synchronization and frequency synchronization of LTE system

Non-Patent Citations (2)

* Cited by examiner, † Cited by third party
Title
LU WU等: "《A Closed-Form Blind CFO Estimator Based on Frequency Analysis for OFDM Systems》", 《IEEE TRANSACTIONS ON COMMUNICATIONS》 *
WEN XU等: "《Robust Synchronization for 3GPP LTE System》", 《IEEE》 *

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