CN102215205A - Orthogonal frequency division multiplexing (OFDM)/offset quadrature amplitude modulation (OQAM) system and time frequency synchronization method thereof - Google Patents

Orthogonal frequency division multiplexing (OFDM)/offset quadrature amplitude modulation (OQAM) system and time frequency synchronization method thereof Download PDF

Info

Publication number
CN102215205A
CN102215205A CN2011102155770A CN201110215577A CN102215205A CN 102215205 A CN102215205 A CN 102215205A CN 2011102155770 A CN2011102155770 A CN 2011102155770A CN 201110215577 A CN201110215577 A CN 201110215577A CN 102215205 A CN102215205 A CN 102215205A
Authority
CN
China
Prior art keywords
time
frequency
value
sequence
adjusted
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
CN2011102155770A
Other languages
Chinese (zh)
Other versions
CN102215205B (en
Inventor
胡苏�
陈浩
武刚
李少谦
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
University of Electronic Science and Technology of China
Original Assignee
University of Electronic Science and Technology of China
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by University of Electronic Science and Technology of China filed Critical University of Electronic Science and Technology of China
Priority to CN 201110215577 priority Critical patent/CN102215205B/en
Publication of CN102215205A publication Critical patent/CN102215205A/en
Application granted granted Critical
Publication of CN102215205B publication Critical patent/CN102215205B/en
Expired - Fee Related legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Images

Landscapes

  • Synchronisation In Digital Transmission Systems (AREA)
  • Digital Transmission Methods That Use Modulated Carrier Waves (AREA)

Abstract

The invention discloses an orthogonal frequency division multiplexing (OFDM)/offset quadrature amplitude modulation (OQAM) system and a time frequency synchronization method thereof. In the system and the method provided by the invention, a one-step synchronization method of a frequency-domain-pilot-based time frequency joint estimation method in the conventional OFDM/OQAM system is extended into a multi-path parallel time frequency joint estimation method, and comprises the following steps of: first obtaining a primary estimated time offset value by using time offset estimation, and expanding the primary estimated time offset value into a regulated time offset test value sequence; then causing each regulated time offset test value to correspond to the demodulation recovery of a path of data respectively; and finally selecting a path of which the data of a pilot part has the smallest bit error rate as an accurate timing path. Therefore, the acquisition probability of the time offset estimation is greatly improved under the condition of correcting the inaccurate primary estimated time offset value to a great extent.

Description

A kind of OFDM/OQAM system and time-frequency synchronization method thereof
Technical field
The invention belongs to the mobile communication technology field, be particularly related to a kind of OFDM (OFDM/OQAM, Orthogonal Frequency Division Multiplexing/Offset Quadrature Amplitude Modulation) system and time-frequency synchronization method thereof of staggered quadrature amplitude modulation.
Background technology
Because wireless user's improving constantly to transmission rate request, multi-carrier modulation technology has become the main flow modulation system of present radio communication, as based on conventional orthogonal frequency division multiplexing (CP-OFDM, the Cyclic Prefix-Orthogonal Frequency Division Multiplexing) technology of Cyclic Prefix with regard to selected be key technology in the LTE standard.And for CP-OFDM, OFDM/OQAM has higher spectrum efficiency, better time-frequency focus characteristics, and for overcoming intersymbol interference (ISI, Inter-Symbol Interference) and inter-carrier interference (ICI, Inter-Carrier Interference) influence all has good effect to a certain extent, the latter particularly becomes OFDM/OQAM with respect to one of main advantage of CP-OFDM.The transmission signal of OFDM/OQAM system is real-valued, takes from the real part and the imaginary part of complex symbol to be passed, and with respect to traditional ofdm system, OFDM/OQAM only satisfies strict orthogonality condition in real number field; Optional usefulness has the isotropism orthogonal transform function (IOTA, Isotropic Orthogonal Transform Algorithm) that good time-frequency focuses on (TFL, Time Frequency Localization) characteristic.
The OFDM/OQAM system sending end structure schematic diagram of using traditional time-frequency combination method of estimation as shown in Figure 1.Comprise signal source module, normal signal processing module, orthogonalization phase mapping module, N point IFFT module, shaping filter module, D/A modular converter, up-conversion module.
For the convenience of describing, at first introduce wherein used term:
(1) shaping filter function g (t) interval t ∈ 0, T s..., (N g-1) T sOn get nonzero value, N wherein g=ξ T/T sFor non-zero sample is counted, ξ is the forming filter tap number, T sBe the systematic sampling time interval, T is the symbol time interval.
(2) frequency domain synchronizing pilot symbol is by the N of continuous transmission TRIndividual OFDM symbol constitutes (N TRAt least bigger by 2 than the tap number ξ of forming filter, could guarantee so partly has the repetition frequency pilot sign through the time domain pilot of transmitting terminal modulation), be about to frequency domain repetition frequency pilot sign and be expressed as
Figure BDA0000079628180000011
L=0 ..., N-1, p=0 ..., N TR-1, wherein N represents sub-carrier number, and l represents the sequence number of subcarrier, and p represents the frequency pilot sign sequence number, and TR represents pilot tone.Through the time-domain pilot signal s after the modulation of transmitting terminal TR(kT s), k ∈ 0,1,2, K, N TRN-1} is at transmission N gAfter-N/2 the sampled point, at interval k ∈ { N of the moment g-N/2 ..., N TRN-N-1} satisfies relational expression s TR(kT s+ NT s)=s TR(kT s).
(3) the baseband receiving signals frame sequence is r (kT s), k ∈ 0,1,2, K}, τ ∈ 0,1, and K, inclined to one side actual value when N/4} is,
Figure BDA0000079628180000012
For the time inclined to one side estimated value,
Figure BDA0000079628180000021
For the time inclined to one side experiment value,
Figure BDA0000079628180000022
Inclined to one side estimated value when preliminary,
Figure BDA0000079628180000023
ε ∈＜-0.5,0.5〉be the frequency deviation actual value that normalizes on the subcarrier spacing,
Figure BDA0000079628180000024
Be the frequency offset estimating value,
Figure BDA0000079628180000025
Be correlated series, R is for asking the phase angular operator, and L is the multipath channel maximum delay, and D is the summation window length of sliding.
At first carry out initialization process: in the register of transmitting terminal (travelling carriage) and receiving terminal (base station), store identical transmission pilot frequency sequence, and will send time domain pilot sequence s at receiving terminal TR(kT s) ξ N+1 to the (N TR-1) N data save as the transmission consensus sequence, in the identical forming filter sequence of transmitting-receiving two-end storage, and set up corresponding rule.Concrete treatment step is as follows:
Step 11. signal source module produces data bit and does coding through the normal signal processing module, quadrature amplitude modulation (QAM, Quadrature Amplitude Modulation), obtain complex data after, framing and to add length at front end be N TRFrequency domain repeat frequency pilot sign
Figure BDA0000079628180000026
L=0 ..., N-1, p=0 ..., N TR-1, then carry out real imaginary component from;
Step 12. is carried out the orthogonalization phase mapping by orthogonalization phase mapping module respectively by the real imaginary part of the data that step 11 obtains;
Step 13. is done anti-fast Fourier transform (IFFT, Inverse Fast Fourier Transform) by the data of step 12 by N point IFFT module, finishes multi-carrier modulation;
The data that step 14. is obtained by step 13 by the forming filter module, are finished the signal moulding, and the string conversion;
Step 15. is transmitted by data process D/A modular converter, up-conversion module that step 14 obtains.
As typical multi-carrier modulation, OFDM/OQAM has the general character of a multi-carrier modulation technology, promptly be subject to carrier frequency shift (CFO, Carrier Frequency Offset) and the influence of time migration, the main cause that CFO produces is because the oscillator of transmitting-receiving two-end is stable inadequately and accurate, the frequency that produces is deviation to some extent, and then has destroyed the orthogonality between subcarrier, and then has introduced ISI and ICI.And owing to do not add CP, in case synchronism deviation occurs, whole discrete Fourier (DFT, Discrete Fourier Transform) window will misplace, and causes the interference that is difficult to recover, thus OFDM/OQAM to the time partially also very responsive.
In order to obtain reasonable systematic function, frequency offset estimating all has than higher precision in the time of just must guaranteeing.T.Fusco, A.Petrella and M.Tanda have proposed based on the autocorrelative MLS time-frequency combination of baseband receiving signals frame sequence second order method of estimation at " Data-Aided Symbol Timing and CFO Synchronization for Filter Bank Multicarrier Systems.IEEE Trans.Wireless Commun.; May 2009; 8 (5): 2705-2715 ", have also enumerated the TR2 time-frequency combination method of estimation of carrying out the quadravalence cross-correlation based on baseband receiving signals frame sequence and transmission consensus sequence.
Fig. 2 is for using the OFDMA/OQAM system receiving terminal fundamental diagram that traditional MLS and TR2 time-frequency combination are estimated, comprise down conversion module, the A/D modular converter, synchronous estimation module, the time compensate of frequency deviation module, matched filtering module, FFT module, go orthogonalization phase mapping module, the normal signal processing module.Suppose that the receiving terminal channel information is known, then receiving terminal can be expressed as following step:
Step 21. received signal obtains baseband receiving signals frame sequence r (kT through down conversion module, A/D modular converter s), k ∈ 0,1,2, K};
The baseband receiving signals frame sequence r (kT that step 22. obtains step 21 s) frequency deviation when estimating by synchronization module, be (N by the baseband receiving signals frame sequence is carried out length TR-1-ξ) (processing method that MLS time-frequency combination method of estimation is adopted specifically can be expressed as the slip auto-correlation of N+1
Figure BDA0000079628180000031
Wherein,
Figure BDA0000079628180000032
Perhaps with baseband receiving signals frame sequence r (kT s) and send consensus sequence s TR(kT s) (processing method that TR2 time-frequency combination method of estimation is adopted specifically can be expressed as to do quadravalence slip computing cross-correlation
Figure BDA0000079628180000034
Wherein,
Figure BDA0000079628180000035
Figure BDA0000079628180000036
Obtain a correlated series
Figure BDA0000079628180000037
Choose
Figure BDA0000079628180000038
When peak value is pairing inclined to one side experiment value as the time inclined to one side estimated value Utilize again
Figure BDA00000796281800000310
Further estimate the frequency offset estimating value
Figure BDA00000796281800000311
Here, " " expression phase multiplication, " * " represents conjugate operation;
During step 23. the compensate of frequency deviation module with step 22 obtain the time partially and the frequency offset estimating value baseband receiving signals frame sequence is compensated;
The data that step 24. obtains step 23 are done matched filtering by the matched filtering module;
Step 25. will through fast Fourier transform (FFT, Fast Fourier Transform) module, be finished the multicarrier demodulation by the data after the step 24;
Step 26. will be gone the orthogonalization phase mapping through past orthogonalization phase mapping module by the data after the step 25;
Step 27. will be by the data after the step 26, eliminate via equalizer (as zero forcing equalization etc.) or reduce the influence of multipath channel to the OFDM/OQAM signal with known channel information;
Step 28. will be carried out real imaginary part by the data after the step 27 and be converged, and carry out QAM demodulation and corresponding decoding, the dateout bit.
Here adopt the OFDM/OQAM system of traditional time-frequency combination method of estimation based on pilot tone to have following shortcoming:
One. directly choose by step 22 obtain the correlated series peak value when pairing inclined to one side experiment value as the time inclined to one side estimated value.When first footpath is not the strongest path of instantaneous power in multipath channel, the time inclined to one side estimated value that obtains like this can automatically become locked on the footpath of instantaneous power maximum, rather than first footpath of wishing, the acquisition probability of having estimated partially when this has influenced greatly, and then directly cause the demodulation operation of receiving terminal step 24 and step 25 to misplace, cause correctly demodulation of receiving terminal.
They are two years old. two kinds of methods estimating partially when step 22 is used for.First method adopts baseband receiving signals frame sequence second order auto-correlation estimating time bias, and the correlation that obtains like this changes milder, than the influence that is easier to be subjected to noise and CFO; Second method adopts the baseband receiving signals frame sequence and sends the quadravalence slip cross-correlation estimating time bias of consensus sequence, and the correlation that obtains like this can obtain than higher relevant peaks at the timing point, but the complexity that realizes increases to some extent.
They are three years old. the slip correlation window scope (N that step 22 is chosen when carrying out associative operation TR-1-ξ) N does not arrive the maximum magnitude that can choose in theory, and inclined to one side estimated accuracy also has certain room for improvement when that is to say.And the frequency offset estimating value is that inclined to one side estimated value calculates when utilizing, and improved space is also arranged.
They are four years old. and traditional time-frequency synchronization method is synchronizing process for once, just can't revise in case timing error occurs.
Summary of the invention
The objective of the invention is the lower problem of acquisition probability estimated partially when solving existing employing, proposed a kind of OFDM/OQAM system and time-frequency synchronization method thereof based on the OFDM/OQAM system of the time-frequency combination method of estimation of pilot tone.
Technical scheme of the present invention is: a kind of OFDM/OQAM system, it is characterized in that, the receiving terminal of described OFDM/OQAM system comprises: the time inclined to one side estimation module, the time inclined to one side distribution module, frequency deviation estimating modules, the time compensate of frequency deviation module, demodulation module and error rate comparison module, wherein
The time inclined to one side estimation module, inclined to one side estimated value when being used to estimate the baseband receiving signals frame sequence that receives preliminary;
The time inclined to one side distribution module, be used for according to the time inclined to one side estimation module obtain preliminary the time inclined to one side estimated value distribute partially when carrying out, obtain that inclined to one side test value sequence is used to be input to each frequency deviation estimating modules when adjusted;
Frequency deviation estimating modules, inclined to one side test value is estimated the frequency offset estimating value of the baseband receiving signals frame sequence that receives when being used for when adjusted inclined to one side experiment value sequence allocation and giving this frequency deviation estimating modules adjusted;
The time compensate of frequency deviation module, be used for the frequency offset estimating value that obtains according to frequency deviation estimating modules with and corresponding compensate of frequency deviation when inclined to one side test value is carried out the baseband receiving signals frame sequence when adjusted, the baseband receiving signals frame sequence after being compensated;
Demodulation module, be used for to the time baseband receiving signals frame sequence after the compensate of frequency deviation module compensation that obtains carry out demodulation, obtain the data bit after the demodulation;
Error rate comparison module, being used for the pilot portion of the data bit that comparison obtains according to each branch road demodulation module and frequency domain repeats the pilot data bit and compares the pilot tone error rate size that obtains, the branch road of judging error rate minimum is a timing branch road accurately, and the data bit after the demodulation of this branch road is exported.
In order to realize that purpose of the present invention has also proposed a kind of OFDM/OQAM system time frequency method for synchronous, comprising: the time inclined to one side estimating step, the time inclined to one side allocation step, frequency offset estimating step, the time compensate of frequency deviation step, demodulation step and error rate comparison step, wherein,
The time inclined to one side estimating step, inclined to one side estimated value when being used to estimate the baseband receiving signals frame sequence that receives preliminary;
The time inclined to one side allocation step, be used for according to the time inclined to one side estimating step obtain preliminary the time inclined to one side estimated value distribute partially when carrying out, obtain that inclined to one side test value sequence is used to be input to each frequency offset estimating step when adjusted;
The frequency offset estimating step, inclined to one side test value is estimated the frequency offset estimating value of the baseband receiving signals frame sequence that receives when being used for when adjusted inclined to one side experiment value sequence allocation and giving this frequency offset estimating step adjusted;
The time compensate of frequency deviation step, be used for the frequency offset estimating value that obtains according to the frequency offset estimating step with and corresponding compensate of frequency deviation when inclined to one side test value is carried out the baseband receiving signals frame sequence when adjusted, the baseband receiving signals frame sequence after being compensated;
Demodulation step, be used for to the time baseband receiving signals frame sequence after the compensate of frequency deviation step compensation that obtains carry out demodulation, obtain the data bit after the demodulation;
Error rate comparison step, being used for the pilot portion of the data bit that comparison obtains according to each branch road demodulation step and frequency domain repeats the pilot data bit and compares the pilot tone error rate size that obtains, the branch road of judging error rate minimum is a timing branch road accurately, and the data bit after the demodulation of this branch road is exported.
Beneficial effect of the present invention: system and method for the present invention expands to multidiameter delay time-frequency combination estimation approach with the step method for synchronous based on the time-frequency combination method of estimation of pilot tone in traditional OFDM/OQAM system, elder generation's time spent estimates to obtain a preliminary time inclined to one side estimated value partially, and it is extended to inclined to one side test value sequence when adjusted, the inclined to one side test value demodulation recovery of a corresponding circuit-switched data respectively when wherein each is adjusted then, the path of choosing pilot portion error rates of data minimum at last is timing path accurately, thereby correct the inaccurate situation of inclined to one side estimated value when preliminary, the acquisition probability of having estimated partially when having improved greatly to a great extent.
Description of drawings
Fig. 1 is the OFDM/OQAM system sending end structure schematic diagram that traditional time-frequency combination is estimated.
Fig. 2 is the OFDM/OQAM system receiving terminal structural representation that traditional time-frequency combination is estimated.
Fig. 3 is an OFDM/OQAM system receiving terminal structural representation of the present invention.
Embodiment
The invention will be further elaborated below in conjunction with accompanying drawing and specific embodiment.
Of the present invention main by following technological means realization:
One, road time-frequency combination method of estimation based on the time-frequency combination method of estimation of pilot tone in just traditional OFDM/OQAM system expands to the method that optimal path is estimated and chosen according to maximum posteriori criterion to the multidiameter delay time-frequency combination.Elder generation's time spent estimates to obtain a preliminary time inclined to one side estimated value partially, and it is extended near 2L (or less than 2L) comprising inclined to one side test value sequence during inclined to one side experiment value adjusted when individual, the inclined to one side test value demodulation recovery of a corresponding circuit-switched data respectively when wherein each is adjusted then, the path of choosing pilot portion error rates of data minimum at last is timing path accurately;
For the effect that further develops skill, the time partially estimate and the process of frequency offset estimating in taked following measure:
Two, carrying out when synchronous the baseband receiving signals frame sequence and sending theoretical expanded range that consensus sequence carries out cross-correlation, and considering the influence that multidiameter delay causes to maximum, chosen the related operation scope of a compromise;
Three, change the related operation of receiving terminal into baseband receiving signals frame sequence and the second order computing cross-correlation that sends consensus sequence;
Four, correlated series is carried out the summation of further sliding window handles, the peak value of choosing gained and sequence mould value as the time inclined to one side estimated value.
Be specifically described below.OFDM/OQAM system of the present invention and time-frequency synchronization method thereof, as shown in Figure 3, the receiving terminal of OFDM/OQAM system comprises: the time inclined to one side estimation module, the time inclined to one side distribution module, frequency deviation estimating modules, the time compensate of frequency deviation module, demodulation module and error rate comparison module, wherein
The time inclined to one side estimation module, be used to estimate the baseband receiving signals frame sequence r that receives 1(kT S) preliminary the time inclined to one side estimated value
Figure BDA0000079628180000061
The time inclined to one side distribution module, be used for according to the time inclined to one side estimation module obtain preliminary the time inclined to one side estimated value
Figure BDA0000079628180000062
Distribute partially when carrying out, obtain that inclined to one side test value sequence is used to be input to each frequency deviation estimating modules when adjusted.
Frequency deviation estimating modules, inclined to one side test value is estimated the baseband receiving signals frame sequence r that receives when being used for when adjusted inclined to one side test value sequence allocation and giving this frequency deviation estimating modules adjusted 1(kT S) the frequency offset estimating value.
The time compensate of frequency deviation module, be used for the frequency offset estimating value that obtains according to frequency deviation estimating modules with and corresponding when adjusted inclined to one side test value to baseband receiving signals frame sequence r 1(kT S) compensate of frequency deviation when carrying out, the baseband receiving signals frame sequence r after being compensated 2(kT S).
Demodulation module, be used for to the time baseband receiving signals frame sequence r after the compensate of frequency deviation module compensation that obtains 2(kT S) carry out demodulation, obtain the data bit after the demodulation.Here the function of demodulation module specific implementation comprises: matched filtering, FFT, go orthogonalization phase mapping and normal signal to handle, concrete, normal signal is handled the function that realizes and comprised: channel estimation balancing, real imaginary part merge, QAM demodulation sign indicating number.Here demodulation module is not elaborating as the known technology means of this area.
Error rate comparison module, being used for the pilot portion of the data bit that comparison obtains according to each branch road demodulation module and frequency domain repeats the pilot data bit and compares the pilot tone error rate size that obtains, the branch road of judging error rate minimum is a timing branch road accurately, and the data bit after the demodulation of this branch road is exported.Here, it is that frequency domain repeats the pairing bit information of frequency pilot sign that frequency domain repeats the pilot data bit, is all known information of transmitting-receiving two-end.
As a preferable scheme, inclined to one side test value sequence is when adjusted here
Figure BDA0000079628180000071
Wherein, L is the multipath channel maximum delay, if Inclined to one side test value sequence is adjusted in the time of then
Figure BDA0000079628180000073
As can be seen, frequency deviation estimating modules, the time compensate of frequency deviation module and demodulation module number number decision of element in the inclined to one side test value sequence when adjusted, determined the number of the receiving terminal branch road of system.
OFDM/OQAM system time frequency method for synchronous of the present invention comprises the steps:
The time inclined to one side estimating step, be used to estimate the baseband receiving signals frame sequence r that receives 1(kT S) preliminary the time inclined to one side estimated value
Figure BDA0000079628180000074
The time inclined to one side allocation step, be used for according to the time inclined to one side estimating step obtain preliminary the time inclined to one side estimated value
Figure BDA0000079628180000075
Distribute partially when carrying out, obtain that inclined to one side experiment value sequence is used to be input to each frequency offset estimating step when adjusted;
The frequency offset estimating step, inclined to one side test value is estimated the baseband receiving signals frame sequence r that receives when being used for when adjusted inclined to one side test value sequence allocation and giving this frequency offset estimating step adjusted 1(kT S) the frequency offset estimating value;
The time compensate of frequency deviation step, be used for the frequency offset estimating value that obtains according to the frequency offset estimating step with and corresponding when adjusted inclined to one side test value to baseband receiving signals frame sequence r 1(kT S) compensate of frequency deviation when carrying out, the baseband receiving signals frame sequence r after being compensated 2(kT S);
Demodulation step, be used for to the time baseband receiving signals frame sequence r after the compensate of frequency deviation step compensation that obtains 2(kT S) carry out demodulation, obtain the data bit after the demodulation;
Error rate comparison step, being used for the pilot portion of the data bit that comparison obtains according to each branch road demodulation step and frequency domain repeats the pilot data bit and compares the pilot tone error rate size that obtains, the branch road of judging error rate minimum is a timing branch road accurately, and the data bit after the demodulation of this branch road is exported.
As a preferable scheme, inclined to one side test value sequence is when adjusted here
Figure BDA0000079628180000076
Wherein, L is the multipath channel maximum delay, if Inclined to one side test value sequence is adjusted in the time of then
Figure BDA0000079628180000078
With this when adjusted during each among the inclined to one side test value sequence inclined to one side test value all distribute a branch road, frequency offset estimating step after being input to calculates corresponding frequency offset estimating value, like this each bar branch road the time partially and the frequency offset estimating value all be different.
Here the estimation procedure the time in inclined to one side estimating step and the frequency offset estimating step can adopt MLS and the TR2 method in the background technology.
As one of the embodiment of the invention preferable scheme, the detailed process of inclined to one side estimating step is as follows when described:
With baseband receiving signals frame sequence r 1(kT S) and send consensus sequence s TR(kT s) to carry out length be (N TR-ξ-1/2) the second order slip computing cross-correlation of N-2L obtains a correlated series
Figure BDA0000079628180000081
Specifically be expressed as
Figure BDA0000079628180000082
Wherein
Figure BDA0000079628180000083
Figure BDA0000079628180000084
Figure BDA0000079628180000085
The slip summation operation of carrying out the long D of fixed window obtains one and sequence
Figure BDA0000079628180000086
D＞L wherein chooses with the peak value of sequence when pairing inclined to one side test value inclined to one side estimated value when preliminary
Figure BDA0000079628180000087
Here, satisfy relational expression s in theory TR(kT s+ NT s)=s TR(kT s) scope (promptly carrying out the scope of associative operation) can expand to [N g-N/2, N TRN-N-1], but in order to remove the influence that multidiameter delay causes, the scope of related operation is adjusted to [N g-N/2+L, N TRN-N-L-1].
As another preferable scheme of the embodiment of the invention, the detailed process of described frequency offset estimating step is as follows:
Inclined to one side test value when inclined to one side test value sequence allocation is given this frequency offset estimating step adjusted when adjusted
Figure BDA0000079628180000088
Substitution ϵ ^ = 1 2 π NT s R { | F ( τ ^ ′ ) | } , Obtain the frequency offset estimating value Here
Figure BDA00000796281800000811
Wherein, N is a sub-carrier number, and L is the multipath channel maximum delay, N TRFor frequency domain repeats frequency pilot sign number, N gFor the non-zero sample of shaping filter function is counted T sBe the systematic sampling time interval.Owing to the frequency offset estimating value by the time inclined to one side estimated value structure come, so the precision of frequency offset estimating has also obtained raising to a certain degree.
As can be seen, inclined to one side estimation module and frequency deviation estimating modules can be respectively applied for the detailed process that realizes inclined to one side estimating step and frequency offset estimating step when above-mentioned here the time.
Expand to the multidiameter delay time-frequency combination based on one road time-frequency combination method of estimation of the time-frequency combination method of estimation of pilot tone in the at first just traditional OFDM/OQAM system of the present invention and estimate, and choose optimal path according to pilot tone error rate size.Be specially: elder generation's time spent partially estimates to obtain inclined to one side estimated value when preliminary, and it is extended near 2L (or less than 2L) comprising inclined to one side test value sequence during inclined to one side experiment value adjusted when individual, the inclined to one side test value demodulation recovery of a corresponding circuit-switched data respectively when each is adjusted then, the path of choosing pilot portion error rates of data minimum at last is timing path accurately.Even such processing makes that timing error appears in inclined to one side estimated value when preliminary, also can correct the inaccurate situation of inclined to one side estimated value when preliminary to a great extent, the acquisition probability of having estimated partially when having improved greatly.Simultaneously, owing to the frequency offset estimating value by the time inclined to one side estimated value structure come, so the precision of frequency offset estimating has also obtained raising to a certain degree; Secondly carrying out when synchronous the baseband receiving signals frame sequence and sending theoretical expanded range that consensus sequence carries out cross-correlation to maximum, and the influence of considering to remove multipath delay simultaneously, promptly the scope of actual cross-correlation is (N TR-ξ-1/2) N-2L can farthest utilize the reception data of frequency deviation information when carrying like this, makes estimated result more accurate; Once more, change the related operation of receiving terminal into baseband receiving signals frame sequence and the second order cross-correlation that sends consensus sequence, such processing is directly done the autocorrelative timing accuracy height of second order than baseband receiving signals frame sequence, also the complexity of doing the quadravalence cross-correlation than baseband receiving signals frame sequence and transmission consensus sequence is low, is guaranteeing to find a balance point preferably between estimated performance and the control implementation complexity; Moreover, the present invention be not directly with the correlated series peak value to seasonable test value partially as the time inclined to one side estimated value, but being carried out further sliding window summation, handles correlated series, the peak value of choosing gained and sequence mould value as the time inclined to one side estimated value, when the left end of the summation window that slides just aligns the channel impulse response in first footpath, all path responses of multipath channel are all in the summation window, what obtain is maximum with value, and when first directly is moved out of outside the summation window, decline to a certain degree appears in meeting with value, so choose with the peak value of sequence when pairing inclined to one side test value as the time inclined to one side estimated value, can be locked in comparatively exactly on the time of advent in first footpath.The bias estimation footpath that instantaneous power is the strongest in multipath channel is not can be locked in the power most powerful path and the timing error that causes under the situation in first footpath in the time of can solving tradition effectively like this, expanded the relevant range of baseband receiving signals frame sequence and transmission consensus sequence simultaneously, and the influence of considering and having removed multidiameter delay, frequency offset estimation accuracy when having improved
Adopt method and system of the present invention, the acquisition probability of estimating partially in the time of can effectively improving and the precision of frequency offset estimating reach the purpose that better satisfies the high-speed mobile communications requirement.
Those of ordinary skill in the art will appreciate that embodiment described here is in order to help reader understanding's principle of the present invention, should to be understood that protection scope of the present invention is not limited to such special statement and embodiment.Those of ordinary skill in the art can make various other various concrete distortion and combinations that do not break away from essence of the present invention according to these technology enlightenments disclosed by the invention, and these distortion and combination are still in protection scope of the present invention.

Claims (8)

1. an OFDM/OQAM system is characterized in that, the receiving terminal of described OFDM/OQAM system comprises: the time inclined to one side estimation module, the time inclined to one side distribution module, frequency deviation estimating modules, the time compensate of frequency deviation module, demodulation module and error rate comparison module, wherein,
The time inclined to one side estimation module, inclined to one side estimated value when being used to estimate the baseband receiving signals frame sequence that receives preliminary;
The time inclined to one side distribution module, be used for according to the time inclined to one side estimation module obtain preliminary the time inclined to one side estimated value distribute partially when carrying out, obtain that inclined to one side test value sequence is used to be input to each frequency deviation estimating modules when adjusted;
Frequency deviation estimating modules, inclined to one side test value is estimated the frequency offset estimating value of the baseband receiving signals frame sequence that receives when being used for when adjusted inclined to one side experiment value sequence allocation and giving this frequency deviation estimating modules adjusted;
The time compensate of frequency deviation module, be used for the frequency offset estimating value that obtains according to frequency deviation estimating modules with and corresponding compensate of frequency deviation when inclined to one side test value is carried out the baseband receiving signals frame sequence when adjusted, the baseband receiving signals frame sequence after being compensated;
Demodulation module, be used for to the time baseband receiving signals frame sequence after the compensate of frequency deviation module compensation that obtains carry out demodulation, obtain the data bit after the demodulation;
Error rate comparison module, being used for the pilot portion of the data bit that comparison obtains according to each branch road demodulation module and frequency domain repeats the pilot data bit and compares the pilot tone error rate size that obtains, the branch road of judging error rate minimum is a timing branch road accurately, and the data bit after the demodulation of this branch road is exported.
2. OFDM/OQAM according to claim 1 system is characterized in that inclined to one side test value sequence is when described
Figure FDA0000079628170000011
Wherein, L is the multipath channel maximum delay,
Figure FDA0000079628170000012
Inclined to one side estimated value when preliminary, if
Figure FDA0000079628170000013
Inclined to one side test value sequence is adjusted in the time of then
Figure FDA0000079628170000014
3. OFDM/OQAM according to claim 1 and 2 system is characterized in that inclined to one side estimation module is used to be achieved as follows process when described:
With baseband receiving signals frame sequence r 1(kT S) and send consensus sequence s TR(kT s) to carry out length be (N TR-ξ-1/2) the second order slip computing cross-correlation of N-2L obtains a correlated series Specifically be expressed as
Figure FDA0000079628170000016
Wherein
Figure FDA0000079628170000017
Figure FDA0000079628170000018
Figure FDA0000079628170000019
The slip summation operation of carrying out the long D of fixed window obtains one and sequence
Figure FDA00000796281700000110
D＞L wherein chooses with the peak value of sequence when pairing inclined to one side test value inclined to one side estimated value when preliminary
Figure FDA00000796281700000111
Wherein, N is a sub-carrier number, and L is the multipath channel maximum delay, N TRFor frequency domain repeats frequency pilot sign number, N gFor the non-zero sample of shaping filter function is counted T sBe the systematic sampling time interval.
4. according to the described arbitrary OFDM/OQAM of claim 1 to 3 system, it is characterized in that described frequency deviation estimating modules is used to be achieved as follows process:
When inclined to one side experiment value sequence allocation is given this frequency deviation estimating modules adjusted when adjusted during inclined to one side experiment value
Figure FDA0000079628170000021
Substitution ϵ ^ = 1 2 π NT s R { | F ( τ ^ ′ ) | } , Obtain the frequency offset estimating value
Figure FDA0000079628170000023
Here
Figure FDA0000079628170000024
Wherein, N is a sub-carrier number, N TRFor frequency domain repeats frequency pilot sign number, N gFor the non-zero sample of shaping filter function is counted T sBe the systematic sampling time interval.
5. an OFDM/OQAM system time frequency method for synchronous is characterized in that, comprising: the time inclined to one side estimating step, the time inclined to one side allocation step, frequency offset estimating step, the time compensate of frequency deviation step, demodulation step and error rate comparison step, wherein,
The time inclined to one side estimating step, inclined to one side estimated value when being used to estimate the baseband receiving signals frame sequence that receives preliminary;
The time inclined to one side allocation step, be used for according to the time inclined to one side estimating step obtain preliminary the time inclined to one side estimated value distribute partially when carrying out, obtain that inclined to one side test value sequence is used to be input to each frequency offset estimating step when adjusted;
The frequency offset estimating step, inclined to one side test value is estimated the frequency offset estimating value of the baseband receiving signals frame sequence that receives when being used for when adjusted inclined to one side experiment value sequence allocation and giving this frequency offset estimating step adjusted;
The time compensate of frequency deviation step, be used for the frequency offset estimating value that obtains according to the frequency offset estimating step with and corresponding compensate of frequency deviation when inclined to one side test value is carried out the baseband receiving signals frame sequence when adjusted, the baseband receiving signals frame sequence after being compensated;
Demodulation step, be used for to the time baseband receiving signals frame sequence after the compensate of frequency deviation step compensation that obtains carry out demodulation, obtain the data bit after the demodulation;
Error rate comparison step, being used for the pilot portion of the data bit that comparison obtains according to each branch road demodulation step and frequency domain repeats the pilot data bit and compares the pilot tone error rate size that obtains, the branch road of judging error rate minimum is a timing branch road accurately, and the data bit after the demodulation of this branch road is exported.
6. OFDM/OQAM system time frequency method for synchronous according to claim 5 is characterized in that inclined to one side test value sequence is when described
Figure FDA0000079628170000025
Wherein, L is the multipath channel maximum delay,
Figure FDA0000079628170000026
Inclined to one side estimated value when preliminary, if
Figure FDA0000079628170000027
Inclined to one side test value sequence is adjusted in the time of then
Figure FDA0000079628170000028
7. according to claim 5 or 6 described OFDM/OQAM system time frequency method for synchronous, it is characterized in that the detailed process of inclined to one side estimating step is as follows when described:
With baseband receiving signals frame sequence r 1(kT S) and send consensus sequence s TR(kT s) to carry out length be (N TR-ξ-1/2) the second order slip computing cross-correlation of N-2L obtains a correlated series
Figure FDA0000079628170000031
Specifically be expressed as Wherein
Figure FDA0000079628170000033
Figure FDA0000079628170000034
Figure FDA0000079628170000035
The slip summation operation of carrying out the long D of fixed window obtains one and sequence
Figure FDA0000079628170000036
D＞L wherein chooses with the peak value of sequence when pairing inclined to one side test value inclined to one side estimated value when preliminary
Figure FDA0000079628170000037
Wherein, N is a sub-carrier number, and L is the multipath channel maximum delay, N TRFor frequency domain repeats frequency pilot sign number, N gFor the non-zero sample of shaping filter function is counted T sBe the systematic sampling time interval.
8. according to the described arbitrary OFDM/OQAM system time frequency method for synchronous of claim 5 to 7, it is characterized in that the detailed process of described frequency offset estimating step is as follows:
Inclined to one side experiment value when inclined to one side experiment value sequence allocation is given this frequency offset estimating step adjusted when adjusted Substitution ϵ ^ = 1 2 π NT s R { | F ( τ ^ ′ ) | } , Obtain the frequency offset estimating value
Figure FDA00000796281700000310
Here
Figure FDA00000796281700000311
Wherein, N is a sub-carrier number, N TRFor frequency domain repeats frequency pilot sign number, N gFor the non-zero sample of shaping filter function is counted T sBe the systematic sampling time interval.
CN 201110215577 2011-07-29 2011-07-29 Orthogonal frequency division multiplexing (OFDM)/offset quadrature amplitude modulation (OQAM) system and time frequency synchronization method thereof Expired - Fee Related CN102215205B (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN 201110215577 CN102215205B (en) 2011-07-29 2011-07-29 Orthogonal frequency division multiplexing (OFDM)/offset quadrature amplitude modulation (OQAM) system and time frequency synchronization method thereof

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN 201110215577 CN102215205B (en) 2011-07-29 2011-07-29 Orthogonal frequency division multiplexing (OFDM)/offset quadrature amplitude modulation (OQAM) system and time frequency synchronization method thereof

Publications (2)

Publication Number Publication Date
CN102215205A true CN102215205A (en) 2011-10-12
CN102215205B CN102215205B (en) 2013-11-06

Family

ID=44746339

Family Applications (1)

Application Number Title Priority Date Filing Date
CN 201110215577 Expired - Fee Related CN102215205B (en) 2011-07-29 2011-07-29 Orthogonal frequency division multiplexing (OFDM)/offset quadrature amplitude modulation (OQAM) system and time frequency synchronization method thereof

Country Status (1)

Country Link
CN (1) CN102215205B (en)

Cited By (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN103023830A (en) * 2012-12-05 2013-04-03 无锡创灵科技有限公司 Turbo iteration detecting device and method directing at big carrier frequency excursion
CN104081738A (en) * 2012-01-13 2014-10-01 奥兰治 Method, devices and computer program product for modulation and demodulation delivering ofdm/oqam symbols
CN104601512A (en) * 2015-01-05 2015-05-06 江苏指南针导航通信技术有限公司 Method and system for detecting carrier frequency offset of phase-modulated signals
CN105245483A (en) * 2015-10-21 2016-01-13 深圳市信安城通科技有限公司 Single-symbol OFDM signal demodulation method and apparatus
WO2016119611A1 (en) * 2015-01-26 2016-08-04 中兴通讯股份有限公司 Data processing method and device
CN106211235A (en) * 2016-06-16 2016-12-07 中国科学技术大学 Parcel data transmission method in a kind of wireless network and system
CN107144343A (en) * 2017-07-10 2017-09-08 薛天 Low-frequency vibration displacement transducer network-building method, system and device
CN110995634A (en) * 2019-12-09 2020-04-10 物格微电子(珠海)有限公司 Rapid frequency offset estimation and compensation system and method under GMSK coherent demodulation
CN111585679A (en) * 2019-02-15 2020-08-25 电信科学技术研究院有限公司 Method and equipment for time self-synchronization in synchronous network
CN114401177A (en) * 2022-03-24 2022-04-26 北京理工大学 Frame synchronization method and device, electronic equipment and storage medium
WO2022134273A1 (en) * 2020-12-23 2022-06-30 重庆邮电大学 Costas sequence time-frequency synchronization method based on all-phase spectrum correction

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101521642A (en) * 2009-04-01 2009-09-02 电子科技大学 Pilot frequency sequence structure in OFDM/OQAM system and method for channel estimation
CN101945066A (en) * 2010-09-16 2011-01-12 电子科技大学 Channel estimation method of OFDM/OQAM system

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101521642A (en) * 2009-04-01 2009-09-02 电子科技大学 Pilot frequency sequence structure in OFDM/OQAM system and method for channel estimation
CN101945066A (en) * 2010-09-16 2011-01-12 电子科技大学 Channel estimation method of OFDM/OQAM system

Cited By (16)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN104081738B (en) * 2012-01-13 2017-06-30 奥兰治 Method, device for delivering the modulation and demodulation of OFDM/OQAM symbols
CN104081738A (en) * 2012-01-13 2014-10-01 奥兰治 Method, devices and computer program product for modulation and demodulation delivering ofdm/oqam symbols
CN103023830A (en) * 2012-12-05 2013-04-03 无锡创灵科技有限公司 Turbo iteration detecting device and method directing at big carrier frequency excursion
CN104601512A (en) * 2015-01-05 2015-05-06 江苏指南针导航通信技术有限公司 Method and system for detecting carrier frequency offset of phase-modulated signals
CN104601512B (en) * 2015-01-05 2018-02-02 江苏指南针导航通信技术股份有限公司 A kind of method and system for detecting phase modulated signal carrier wave frequency deviation
WO2016119611A1 (en) * 2015-01-26 2016-08-04 中兴通讯股份有限公司 Data processing method and device
CN105245483A (en) * 2015-10-21 2016-01-13 深圳市信安城通科技有限公司 Single-symbol OFDM signal demodulation method and apparatus
CN106211235A (en) * 2016-06-16 2016-12-07 中国科学技术大学 Parcel data transmission method in a kind of wireless network and system
CN107144343A (en) * 2017-07-10 2017-09-08 薛天 Low-frequency vibration displacement transducer network-building method, system and device
CN111585679A (en) * 2019-02-15 2020-08-25 电信科学技术研究院有限公司 Method and equipment for time self-synchronization in synchronous network
CN110995634A (en) * 2019-12-09 2020-04-10 物格微电子(珠海)有限公司 Rapid frequency offset estimation and compensation system and method under GMSK coherent demodulation
CN110995634B (en) * 2019-12-09 2022-07-08 物格微电子(珠海)有限公司 Rapid frequency offset estimation and compensation system and method under GMSK coherent demodulation
WO2022134273A1 (en) * 2020-12-23 2022-06-30 重庆邮电大学 Costas sequence time-frequency synchronization method based on all-phase spectrum correction
US11695600B2 (en) 2020-12-23 2023-07-04 Chongqing University Of Posts And Telecommunications Costas sequence time-frequency synchronization method based on all-phase spectrum correction
CN114401177A (en) * 2022-03-24 2022-04-26 北京理工大学 Frame synchronization method and device, electronic equipment and storage medium
CN114401177B (en) * 2022-03-24 2022-07-01 北京理工大学 Frame synchronization method and device, electronic equipment and storage medium

Also Published As

Publication number Publication date
CN102215205B (en) 2013-11-06

Similar Documents

Publication Publication Date Title
CN102185822B (en) OFDM/OQAM (Orthogonal Frequency Division Multiplexing/Offset Quadrature Amplitude Modulation) system and time frequency synchronization method thereof
CN102215205B (en) Orthogonal frequency division multiplexing (OFDM)/offset quadrature amplitude modulation (OQAM) system and time frequency synchronization method thereof
CN102215204B (en) Feedback-iteration-based OFDM/OQAM (orthogonal frequency division multiplexing/offset quadrature amplitude modulation) system as well as time-frequency synchronization method thereof
CN107426123B (en) Method and device for carrying out joint integer frequency offset estimation by using multi-intersymbol pilot frequency
CN110493156B (en) Frequency offset estimation method based on constellation point diversity in 5G mobile communication system
CN101437005B (en) Method for estimating integer multiple frequency deviation with timing error during communication synchronization process
CN101199177B (en) Receiver apparatus for receiving a multicarrier signal
CN101547062B (en) Method and device for correcting frequency deviation
CN1917491B (en) OFDM synchronization method of using training circulated prefix
CN101662434B (en) WiMAX channel estimation method designed by utilizing pilot frequency format
CN107086974A (en) A kind of OFDM synchronous method under high dynamic environment
Nasir et al. Performance of coarse and fine timing synchronization in OFDM receivers
CN101729479B (en) Blind channel estimation method based on cyclostationarity of OFDM signals
CN101022443B (en) OFDM frequency-offset estimating method based on allocycly adjacent structure
CN101667982A (en) Removing method of WiMAX fast fading ICI based on plane spreading kalman filtering wave
CN103078819B (en) Fine symbol timing synchronization method and device thereof
CN102256347B (en) The synchronous method of flexible sub-carrier ofdm system and device
Doğan et al. Time and frequency synchronization with channel estimation for SC-FDMA systems over time-varying channels
CN103095627A (en) Orthogonal frequency division multiplexing (OFDM) technology system synchronization method and electronic device
CN103346985A (en) Method for fast estimating time-frequency parameters in TD-LTE system
Huan et al. Cell search algorithms for the 3G long-term evolution
CN102821078B (en) Blind channel estimation method based on OFDM (orthogonal frequency division multiplexing) signal cyclostationary features
Kung et al. Frequency domain symbol synchronization for OFDM systems
CN115514606B (en) High-precision timing estimation method based on mutual quality sampling
Aboltins et al. Synchronization and correction of channel parameters for an OFDM-based communication system

Legal Events

Date Code Title Description
C06 Publication
PB01 Publication
C10 Entry into substantive examination
SE01 Entry into force of request for substantive examination
C14 Grant of patent or utility model
GR01 Patent grant
CF01 Termination of patent right due to non-payment of annual fee

Granted publication date: 20131106

Termination date: 20160729

CF01 Termination of patent right due to non-payment of annual fee