CN101312442A - Estimation method and estimation unit for frame head and integral frequency bias of receiver frame head - Google Patents

Abstract

The invention discloses an estimation method and an estimation unit for the phase and integer frequency bias of the frame head of a receiver, which comprises attaining the coarse synchronization position of the frame and the frame head mode sent from the transmitting terminal, estimating the combination of the frame head phase and the carrier frequency bias, to estimate the frame head phase and attain the slender synchronization position. The invention estimates the combination of the frame head phase and the carrier frequency bias, but not estimates them independently, to prevent the effect of the carrier frequency bias on the phase estimation and overcome the problems in traditional methods.

Description

The method of estimation and the estimation unit of a kind of receiver frame head phase place and integer frequency bias

Technical field

The present invention relates to moving communicating field, relate in particular to the method for estimation and the estimation unit of a kind of receiver frame head phase place and integer frequency bias.

Background technology

In communication system,, just need carry out rational channel estimating for the data of being transmitted in the correct demodulation of receiving terminal.At present, be used to estimate that the method for wireless channel has two classes greatly, a class is based on training sequence, and a class is based on pilot tone.

Be the channel estimating of example explanation with DTMB (Digital Terrestrial/Television Multimedia Broadcasting, digital TV ground multimedia broadcasting) based on training sequence.

At first specifically introduce frame structure and frame head sequence in the DTMB system, the frame head PN sequence as training sequence in the DTMB standard has three kinds: PN420, PN595 and PN945.

Fig. 1 has provided four layers of frame structure based on multi-frame of DTMB system.Signal frame is the most basic transmission unit, comprises frame head and frame.Frame head is filled the PN sequence, and frame can be the data of single carrier mode, also can be the data of multi-carrier mode.Under multi-carrier mode, the size of IFFT (Inverse Fast FourierTransform, fast adverse Fourier transform) is 3780 points.The length of frame head PN sequence has three kinds: 420 data symbols, 595 data symbols and 945 data symbols, thus there are three kinds of signal frame length accordingly.The baseband sampling rate of DTMB system is 7.56 MSPS (Mega-Samples-Per-Second, per second sample 1,000,000 times).Therefore, the time span of Dui Ying three kinds of PN frame head sequences is respectively 420/7.56=55.56 microsecond, 595/7.56=78.703 microsecond and 945/7.56=125 microsecond.And the time span of frame is 500 microseconds.Thereby the time span of each signal frame is respectively 555.56 microseconds, 578.703 microseconds and 625 microseconds accordingly.Be superframe on signal frame, the time span of each superframe is unified to be 125ms.Accordingly, a superframe comprises 225,216 and 200 signal frames respectively.For dividing frame, time span is one minute on the superframe.A branch frame comprises 480 superframes.Up be a day frame again, corresponding one day 24 hours.One day, frame comprised 1440 branch frames.

The building method of three kinds of PN frame head sequences is also inconsistent.Fig. 2 has provided the structure chart of frame head PN420 sequence.The centre is the PN255 sequence, is the m sequence on one 8 rank, and reaching " 1 " through " 0 " to+1 value is the binary character of non-return-to-zero to the mapping transformation of-1 value.The PN420 sequence comprises synchronizing sequence (length is 83 symbols) behind a preamble sequence (length is 82 symbols), PN255 sequence and.Preamble sequence is the Cyclic Prefix sequence of PN255 sequence, and back synchronizing sequence is the cyclic suffix sequence of PN255 sequence.The PN255 sequence adopts LFSR (Linear Feedback Shift Register, linear feedback shift register) to generate, and the initial phase of different LFSR will generate different PN255 sequences.

Fig. 3 has provided the structure of frame head PN945 sequence.The structure of PN945 and the similar of PN420 all have preamble sequence and back synchronizing sequence.The intermediate sequence of PN945 sequence is a PN511 sequence, adopts the m sequence on one 9 rank to generate, and the mapping transformation to-1 value is the binary symbol sequence of non-return-to-zero to+1 value and " 1 " through " 0 " again.The concrete value of PN945 sequence also is variable, and is relevant with the initial phase of LFSR.And in order to reduce adjacent PN420 sequence or the correlation between the PN945 sequence, the DTMB standard has been arranged initial phase once meticulously by Computer Simulation specially.

The building method of frame head PN420 and PN945 is the same, but the building method of the building method of frame head PN595 and PN420 and PN945 differs widely.The PN595 sequence is to adopt 10 rank maximum length pseudo-random binary sequence brachymemmas to form, and is that length is preceding 595 chips of 1023 m sequence.And the initial phase of LFSR that generates the m sequence of this 1023 length is also fixed, and is 0000000001, and promptly the PN595 sequence that adopts of each signal frame is identical.Preceding 595 chips of pseudo random sequence, the mapping transformation to-1 value is the binary symbol sequence of non-return-to-zero to+1 value and " 1 " through " 0 ", is PN595 frame head sequence.

Receiver is after received signal, earlier the supposition known transmitter is launched which kind of frame head sequence one of (three kinds frame head sequence PN420, PN595 and PN945), on receiver, utilize frame head sequence that is stored in local correspondence in advance and the signal that receives to carry out cross-correlation operation then, seek the output result's of cross-correlation operation amplitude peak value, and then the original position of PN frame head in definite received signal, know frame head PN pattern (one of PN420, PN595 or PN945), PN sequence phase and the frame head PN sequence of transmitter emission, and estimate carrier frequency offset.

Because the PN sequence phase of PN595 frame head mode correspondence can not change, therefore do not need the phase place of PN595 sequence is estimated at receiving terminal.Equally, the PN sequence phase of PN420 frame head mode and PN945 frame head mode correspondence might change, therefore carry out to estimate the phase place of PN420 and PN945 sequence before channel estimating and the deletion of PN sequence that concrete estimating of task comprises whether the phase place of PN sequence changes and the phase place of concrete PN sequence at receiving terminal; Traditional method usually is to utilize local PN sequence and the method for directly carrying out cross correlation process without the received signal of synchronous and compensate of frequency deviation, and these methods are subjected to the influence of carrier wave frequency deviation easily, even when carrier wave frequency deviation is big, often cause misjudgment.And conventional method often is difficult to satisfactory to both partiesly, can't guarantee simultaneously that the estimation of carrier wave frequency deviation and frame head phase place is all accurate as far as possible.

Summary of the invention

The technical problem to be solved in the present invention provides the method for estimation and the estimation unit of a kind of receiver frame head phase place and integer frequency bias, finish the Processing tasks of fine synchronization in the time of can conducting frame head phase estimation, make to estimate the influence that phase place is not subjected to carrier wave frequency deviation.

In order to address the above problem, the invention provides the method for estimation of a kind of receiver frame head phase place and integer frequency bias, comprising:

Behind the frame head mode of the thick sync bit of acquisition frame and transmitting terminal emission, frame head phase place and carrier wave frequency deviation gang are estimated, obtained thin sync bit when estimating the frame head phase place.

Further, described method of estimation specifically comprises:

Behind the frame head mode of the thick sync bit of acquisition frame and transmitting terminal emission, obtain with this frame head mode under various frame head phase places received signal sequence one to one respectively, after each received signal sequence is carried out the integer frequency bias compensation according to each integer frequency bias value respectively, carry out cross-correlation operation with the local PN sequence of selecting, obtain Q * R kind cross correlation results altogether, wherein Q is the species number of frame head phase place, the integer frequency bias value number of R for occurring; Pairing frame head phase place of result that correlation is best and integer frequency bias value are frame head phase place and the integer frequency bias value that estimates.

Further, obtain with this frame head mode under various frame head phase places respectively one to one the received signal sequence specifically be meant:

From received signal, choose Q section received signal sequence as pending data sequence r _{Pn, w}(n), w is the sequence number of pending data sequence; The length of every segment data sequence is 2L _{Ds, max}+ P data sample, the pending data sequence of this Q section is respectively one by one corresponding to all Q PN sequence phases; P is the length of frame head PN sequence; L _{Ds, max}Receive the requirement of the maximum delay expansion of machine for system docking.

Further, the concrete system of selection of the pending data sequence of each section comprises:

The span of the index n of sample of signal is I in the pending data sequence of each section _{Coarse, w}-L _{Ds, max}To I _{Coarse, w}+ L _{Ds, max}Each integer of+P-1 comprises I _{Coarse, w}-L _{Ds, max}And I _{Coarse, w}+ L _{Ds, max}+ P-1; I _{Coarse, w}=I _{Coarse, w-1}+ P+D, I _{Coarse, 0}=I _Coarse, I _CoarseBe the index of thick sync bit, D is the frame data length, D=3780 in the DTMB system; I _{Coarse, w}Update cycle be the cycle of transmitting terminal when repeating to send the frame head PN sequence of out of phase.

Further, the described local PN sequence of selecting is a secondary processing sequence, and length is P, and P is the length of frame head PN sequence, is arbitrary local frame head PN sequence corresponding frame head mode, that phase place changes.

Further, each received signal sequence is carried out after the integer frequency bias compensation according to each integer frequency bias value respectively and the local PN sequence selected is carried out cross-correlation operation and specifically comprised:

The pending data sequence of Q section is carried out following operation respectively:

Treat the deal with data sequence and carry out the integer frequency bias compensation by different integer frequency bias values;

For carrying out cross-correlation operation with secondary processing sequence respectively according to the pending sequence after the different integer frequency bias value compensation.

Further, for the DTMB system:

The integer frequency bias that is compensated is k * Δ B, and wherein, integer factor k is taken as respectively-δ _{I, max}To+δ _{I, max}In each integer, comprise-δ _{I, max}With+δ _{I, max}

$\mathrm{\ΔB}=\frac{F}{N+L}\mathrm{Hz},$ F is the baseband sampling rate of system, is 165 for PN420 frame head mode N, and L is 90; For PN420 frame head mode N is 434, and L is 77; Receiver to the area requirement of integer frequency bias is-δ _{I, max}* Δ B arrives+δ _{I, max}* Δ B comprises-δ _{I, max}* Δ B and+δ _{I, max}* Δ B, wherein δ _{I, max}＞0, be integer, R=2 δ _{I, max}+ 1.

Further, best pairing frame head phase place of result and the integer frequency bias value of correlation is that frame head phase place and the integer frequency bias value that estimates is meant:

Correlated series for cross-correlation operation obtains further obtains its power sequence, can obtain R * Q power sequence altogether; Find out the maximum power value P in this R * Q power sequence _{Corr, max}And the average power P of the power sequence at place _{Corr, avg}And this maximum power value P _{Corr, max}Corresponding sample point index I in power sequence _{Corr, peak}, and obtain this maximum power value P _{Corr, max}The pending data sequence of Shi Suoyong and integer frequency bias value F;

Upgrade receiver state, enter tracking mode; Determine that F is integer frequency bias; Determine I _{Coarse, W}+ I _{Corr, peak}-L _{Ds, max}Be the fine synchronization location index of acquisition;

Judge P _{Corr, max}Whether greater than or more than or equal to T _Power* P _{Corr, avg}, T wherein _PowerBe the power factor threshold value, if then obtain maximum power value P _{Corr, max}The phase place of the pending data sequence correspondence of Shi Suoyong is local sequence s _{Pn, q}(n) Dui Ying phase place, otherwise, show that then there is not phase change in frame head PN sequence.

Further, for DTMB system, T _Power=64.

The present invention also provides the estimation unit of a kind of receiver frame head phase place and integer frequency bias, comprising:

The secondary processing sequence generation module is used to select local PN sequence to send to cross-correlation module;

Cross-correlation module is used to receive sequence after compensation and local PN sequence, and two sequences are carried out cross-correlation operation, and cross correlation results is sent to Executive Module.

Executive Module, be used for behind the frame head mode of thick sync bit that obtains frame and transmitting terminal emission, various frame head phase places difference under generation and this frame head mode are the received signal sequence one to one, each received signal sequence is carried out the integer frequency bias compensation according to each integer frequency bias value respectively, and the received signal sequence after will compensating sends to cross-correlation module; And the pairing frame head phase place of result that correlation in Q * R kind cross correlation results is best and integer frequency bias value are as frame head phase place that estimates and the output of integer frequency bias value; Wherein Q is the species number of frame head phase place, the integer frequency bias value number of R for occurring.

Further, the secondary processing sequence generation module selects local PN sequence specifically to be meant:

The secondary processing sequence generation module is according to the frame head mode of having known, the arbitrary local frame head PN sequence that has phase change of choosing corresponding frame head mode is as secondary processing sequence.

Further, Executive Module specifically comprises:

Pending data sequence generates submodule, is used for choosing Q segment data sequence as pending data sequence r from received signal _{Pn, w}(n), the length of every segment data sequence is 2L _{Ds, max}+ P data sample, the pending data sequence of this Q section is respectively one by one corresponding to all Q PN sequence phases; And the corresponding pending data sequence of transmission compensates submodule to integer frequency bias under the indication of control submodule;

Integer frequency bias compensation submodule is used to receive the integer frequency bias value that control module provides and treats the deal with data sequence and generates the pending data sequence that submodule sends and carry out the integer frequency bias compensation, and sequence after compensation is sent to cross-correlation module;

The control submodule is used for beginning to indicate pending data sequence to generate submodule and sending one section pending data sequence behind the frame head mode of thick sync bit that obtains frame and transmitting terminal emission; Every indication sends one section, and just sending different R integer frequency bias value respectively compensates submodule to integer frequency bias; After all integer frequency bias values all send, indicate pending data sequence to generate submodule again and send the pending data sequence of next section, all send up to the pending data sequence of Q section; And the correlated results that receives cross-correlation module, and obtain its power sequence; And find out R * Q the maximum power value P in the power sequence _{Corr, max}And the average power P of the power sequence at place _{Corr, avg}And this maximum power value P _{Corr, max}Corresponding sample point index I in power sequence _{Corr, peak}, and obtain this maximum power value P _{Corr, max}The pending data sequence of Shi Suoyong and integer frequency bias value F; And the renewal receiver state is a tracking mode; With F as integer frequency bias, I _{Coarse, W}+ I _{Corr, peak}-L _{Ds, max}As the fine synchronization location index output that obtains; And judgement P _{Corr, max}Whether more than or equal to T _Power* P _{Corr, avg}, if, then with maximum power value P _{Corr, max}The phase place of the pending data sequence correspondence of Shi Suoyong is as local sequence s _{Pn, q}(n) Dui Ying phase place; Otherwise think that there is not phase change in frame head PN sequence;

Wherein, Q is the species number of frame head phase place, and P is the length of frame head PN sequence; L _{Ds, max}Receive the requirement of the maximum delay expansion of machine for system docking; I _CoarseIndex for thick sync bit.

Further, the pending data sequence span that generates the index n of sample of signal in the pending data sequence of each section that submodule chooses is I _{Coarse, w}-L _{Ds, max}To I _{Coarse, w}+ L _{Ds, max}Each integer of+P-1 comprises I _{Coarse, w}-L _{Ds, max}And I _{Coarse, w}+ L _{Ds, max}+ P-1, I _{Coarse, w}=I _{Coarse, w-1}+ P+D, I _{Coarse, 0}=I _Coarse, I _CoarseBe the index of thick sync bit, D is the frame data length, D=3780 in the DTMB system; I _{Coarse, w}Update cycle be the cycle of transmitting terminal when repeating to send the frame head PN sequence of out of phase.

Further, for the DTMB system:

Q=225 when adopting the PN420 frame head mode, Q=200 when adopting the PN945 frame head mode;

Receiver to the area requirement of integer frequency bias is-δ _{I, max}* Δ B arrives+δ _{I, max}* Δ B comprises-δ _{I, max}* Δ B and+δ _{I, max}* Δ B, wherein δ _{I, max}＞0, be integer, R=2 δ _{I, max}+ 1; $\mathrm{\ΔB}=\frac{F}{N+L}\mathrm{Hz},$ F is the baseband sampling rate of system, is 165 for PN420 frame head mode N, and L is 90; For PN420 frame head mode N is 434, and L is 77;

The control integer frequency bias value that submodule sent is k * Δ B, and integer factor k is taken as respectively-δ _{I, max}To+δ _{I, max}In each integer, comprise-δ _{I, max}With+δ _{I, max}

Further, the control submodule also comprises:

The maximum power value register is used to preserve the maximum power value P of all correlated serieses _{Corr, max}, its initial value is changed to 0;

The average power value register is used for preserving corresponding to maximum power value P _{Corr, max}The average power content P of correlated series _{Corr, avg}, its initial value is changed to 0;

Sample point index value register is used to preserve maximum power value P _{Corr, max}Sample point index value I in the corresponding correlated series _{Corr, peak}, its initial value is changed to 0;

The integer factor register is used to preserve the integer factor δ of integer frequency bias correspondence _{I, corr}, its initial value is changed to 0;

The frame head data serial number register is used to preserve local PN sequence s _{Pn, q}(n) the sequence number W of Dui Ying frame head data, its initial value is changed to 0;

Further, the control submodule is found out R * Q the maximum power value P in the power sequence _{Corr, max}And the average power P of the power sequence at place _{Corr, avg}And this maximum power value P _{Corr, max}Corresponding sample point index I in power sequence _{Corr, peak}, and obtain this maximum power value P _{Corr, max}The pending data sequence of Shi Suoyong and integer factor δ _{I, corr}Specifically refer to:

Maximum power value for each power sequence is P _{Corr, max} ^t, the control submodule is judged P _{Corr, max} ^tWhether greater than P _{Corr, max}If, greater than, then with P _{Corr, max} ^tBe kept at the maximum power value register, with P _{Corr, avg} ^tBe kept at the average power value register, with I _{Corr, peak} ^tBe kept at sample point index value register, k is kept at the integer factor register, the sequence number w of pending data sequence is kept at the frame head data serial number register; Otherwise, then do not carry out any operation.

Further, for DTMB system, T _Power=64.

The present invention proposes a kind of brand-new estimation scheme, no longer frame head phase place and carrier wave frequency deviation is estimated respectively as two independent sectors, but is done as a wholely to estimate, makes phase estimation can not be subjected to the influence of carrier wave frequency deviation, has overcome traditional prejudice.Prioritization scheme of the present invention is all verified possible frame head phase place and carrier wave frequency deviation, estimate the frame head phase place again after compensating to received signal earlier, framing head phase place when finding out the correlation maximum and carrier wave frequency deviation are as estimated result, so accuracy of this group carrier wave frequency deviation among this result and frame head phase place is all than higher.Prioritization scheme of the present invention gives the determination methods of estimated result and thresholding, and estimated result is screened, and can further improve reliability.

Description of drawings

Fig. 1 is based on the schematic diagram of four layers of frame structure of multi-frame in the DTMB system;

Fig. 2 is the structural representation of the frame head PN420 sequence in the DTMB system;

Fig. 3 is the structural representation of the frame head PN945 sequence in the DTMB system;

Fig. 4 is the structural representation after the frame head PN420 sequence transformation;

Fig. 5 is the structural representation after the frame head PN945 sequence transformation;

Fig. 6 is the structural representation that goes for three kinds of frame head sequences;

Fig. 7 is the concrete implementing procedure figure of the method for estimation of receiver frame head phase place provided by the invention and integer frequency bias;

Fig. 8 is the concrete enforcement block diagram of the estimation unit of receiver frame head phase place provided by the invention and integer frequency bias.

Embodiment

Below in conjunction with drawings and Examples technical scheme of the present invention is described in detail.

The frame head phase estimation that the present invention is directed to receiver in the transmission system subjects to carrier wave frequency deviation influences this phenomenon, the estimation scheme of a kind of frame head phase place and carrier wave frequency deviation has been proposed, when carrying out phase estimation, also finish the Processing tasks of fine synchronization, and overcome all shortcomings of above-mentioned traditional scheme.It is to be noted, PN sequence phase that the present invention proposes and integer frequency bias associating estimation scheme are applicable to the situation that the PN sequence phase can change, situation when adopting PN420 frame head mode and PN945 frame head mode in the DTMB system, because the phase place for its PN sequence of PN595 frame head mode is constant, do not need to estimate.

After obtaining thick sync bit and having known the frame head mode of transmitter emission,, just can carry out the estimation scheme of the present invention's proposition at the frame head mode that phase change is arranged.

The method of estimation of a kind of receiver frame head phase place and integer frequency bias comprises:

Behind the frame head mode of the thick sync bit of acquisition frame and transmitting terminal emission, frame head phase place and carrier wave frequency deviation gang are estimated, obtained thin sync bit when estimating the frame head phase place.

What method of the present invention proposed is a kind of brand-new estimation scheme, no longer frame head phase place and carrier wave frequency deviation is estimated respectively that as two independent sectors this method has overcome traditional prejudice.

Wherein, this method specifically comprises:

Behind the frame head mode of the thick sync bit of acquisition frame and transmitting terminal emission, obtain with this frame head mode under various frame head phase places received signal sequence one to one respectively, after each received signal sequence is carried out the integer frequency bias compensation according to each integer frequency bias value respectively, carry out cross-correlation operation with the local PN sequence of selecting, obtain Q * R kind cross correlation results altogether, wherein Q is the species number of frame head phase place, such as for the DTMB system, Q=225 when adopting the PN420 frame head mode, Q=200 when adopting the PN945 frame head mode; The integer frequency bias value number of R for occurring; Pairing frame head phase place of result that correlation is best and integer frequency bias value are frame head phase place and the integer frequency bias value that estimates.

Wherein, this method adopts bicirculating mode to carry out, can be after according to an integer frequency bias value receiving sequence being compensated earlier, respectively according to the sequence of various frame head phase places, carry out cross-correlation operation, according to after a kind of integer frequency bias value compensates receiving sequence down, adopt the sequence of various frame head phase places to carry out cross-correlation operation more respectively ... by that analogy then; Also can be to adopt a kind of sequence of frame head phase place to carry out cross-correlation operation, according to every kind of integer frequency bias value receiving sequence is compensated respectively before the cross-correlation, adopt the sequence of another kind of frame head phase place to carry out cross-correlation operation then, also according to every kind of integer frequency bias value receiving sequence is compensated respectively before the cross-correlation ... by that analogy.

Wherein, obtain with this frame head mode under various frame head phase places respectively one to one the received signal sequence specifically be meant:

From received signal, choose Q section received signal sequence as pending data sequence r _{Pn, w}(n), w is the sequence number of pending data sequence; The length of every segment data sequence is 2L _{Ds, max}+ P data sample, the pending data sequence of this Q section is respectively one by one corresponding to all Q PN sequence phases.

Wherein, the concrete system of selection of the pending data sequence of each section comprises:

The span of the index n of sample of signal is from I in the pending data sequence of each section _{Coarse, w}-L _{Ds, max}To I _{Coarse, w}+ L _{Ds, max}Each integer of+P-1 comprises I _{Coarse, w}-L _{Ds, max}And I _{Coarse, w}+ L _{Ds, max}+ P-1; I wherein _{Coarse, w}=I _{Coarse, w-1}+ P+D, I _{Coarse, 0}=I _Coarse, D is the frame data length, in the DTMB system, and D=3780.

Wherein, the described local PN sequence of selecting is a secondary processing sequence, and length is P, and P is the length of frame head PN sequence, is arbitrary local frame head PN sequence corresponding frame head mode, that phase place changes.

Wherein, each received signal sequence is carried out after the integer frequency bias compensation according to each integer frequency bias value respectively and the local PN sequence selected is carried out cross-correlation operation and specifically comprised:

The pending data sequence of Q section is carried out following operation respectively:

Treat the deal with data sequence and carry out the integer frequency bias compensation by different integer frequency bias values;

For carrying out cross-correlation operation with secondary processing sequence respectively according to the pending sequence after the different integer frequency bias value compensation.

Wherein, best pairing frame head phase place of result and the integer frequency bias value of correlation is that frame head phase place and the integer frequency bias value that estimates is meant:

Correlated series for cross-correlation operation obtains further obtains its power sequence, can obtain R * Q power sequence altogether; Find out the maximum power value P in this R * Q power sequence _{Corr, max}And the average power P of the power sequence at place _{Corr, avg}And this maximum power value P _{Corr, max}Corresponding sample point index I in power sequence _{Corr, peak}, and obtain this maximum power value P _{Corr, max}The pending data sequence of Shi Suoyong and integer frequency bias F.

Upgrade receiver state, enter tracking mode; Determine that F is integer frequency bias; Determine I _{Coarse, W}+ I _{Corr, peak}-L _{Ds, max}Be the fine synchronization location index of acquisition;

Judge P _{Corr, max}Whether greater than or more than or equal to T _Power* P _{Corr, avg}, T wherein _PowerBe the power factor threshold value, if then obtain maximum power value P _{Corr, max}The phase place of the pending data sequence correspondence of Shi Suoyong is local sequence s _{Pn, q}(n) Dui Ying phase place, otherwise, show that then there is not phase change in frame head PN sequence.

Introduce the detailed step that said method is used below in the DTMB system.

Before the explanation detailed step, at first introduce the conversion that PN420 sequence and PN945 sequence are carried out.Here said " conversion " is meant that the segregation method to existing frame head sequential structure carries out conversion, and actual frame head sequence is not changed.The purpose of conversion is in order to make the frame head sequence form the unified structure form.

Existing P N420 sequential structure as shown in Figure 2, wherein, the PN255 sequence can be regarded as by three parts and form, first is the part of horizontal line striped among the figure, is 83 symbols, this back synchronizing sequence a part of and in the PN420 sequence is identical; Last part is the part of vertical line clause among the figure, is 82 symbols, and this preamble sequence a part of and in the PN420 sequence is identical; Therefore, the PN420 sequence can be regarded as form as shown in Figure 4, regard preceding 165 symbols as CP, then 255 symbols are regarded a PN sequence as, in order to distinguish mutually with original PN255 sequence, the PN sequence of these 255 symbols are called new PN255 sequence.As from the foregoing, last 165 symbols (Fig. 4 bend part) in the described new PN255 sequence are identical PN sequences with being positioned at this new PN255 sequence 165 symbols before, therefore when adopting frame head PN420 sequence, be equivalent to have in the frame head two identical PN sequences, length is 165 symbols separately, is spaced apart 90 symbols.

Existing P N945 sequential structure as shown in Figure 3, wherein, the PN511 sequence can be regarded as by three parts and form, first is the part of horizontal line striped among the figure, is 217 symbols, this back synchronizing sequence a part of and in the PN420 sequence is identical; Last part is the part of vertical line clause among the figure, is 217 symbols, and this preamble sequence a part of and in the PN420 sequence is identical; Therefore, the PN420 sequence can be regarded as form as shown in Figure 5, regard preceding 434 symbols as Cyclic Prefix, then 511 symbols are regarded a PN sequence as, in order to distinguish mutually, the PN sequence of these 511 symbols is called new PN511 sequence with original PN511 sequence.As from the foregoing, last 434 symbols (Fig. 5 bend part) in the described new PN511 sequence are identical PN sequences with being positioned at this new PN511 sequence 434 symbols before, therefore when adopting frame head PN420 sequence, be equivalent to have in the frame head two identical PN sequences, length is 434 symbols separately, is spaced apart 77 symbols.

As seen, three kinds of frame head sequences in the DTMB system can be regarded as and have identical version, as shown in Figure 6, all are to be the signal of L across a segment length between two identical, PN sequences that length is N.For frame head PN595 sequence, be identical PN595 sequence will occur, so L is equivalent to the length of frame every a frame, be 3780, N is 595.For frame head PN420 sequence, from preamble as can be known, N is 165, and L is 90.For frame head PN945 sequence, from preamble as can be known, N is 434, and L is 77.

Can remember that receiver to the area requirement of integer frequency bias is-δ _{I, max}* Δ B～+ δ _{I, max}* Δ B, wherein δ _{I, max}＞0, be integer, $\mathrm{\ΔB}=\frac{F}{N+L}\mathrm{Hz},$ F is the baseband sampling rate of system, and N and L are as mentioned before; The integer frequency bias value number R=2 δ that then may occur _{I, max}+ 1.

When being 7.56MHz such as baseband sampling rate when system, for the PN420 frame head mode, Δ B=7.5610 ³/ 255=29.647KHz; For the PN595 frame head mode, Δ B=7.5610 ³/ 4375=1.728KHz; For the PN945 frame head mode, Δ B=7.5610 ³/ 511=14.79452KHz.

The detailed step of said method comprises as shown in Figure 7 in the DTMB system:

The carrier frequency offset that exists between the transmitter and receiver is designated as Δ fHz.Generally carrier wave frequency deviation Δ f can be carried out normalized, i.e. δ=Δ f/ Δ B, δ=δ _I+ δ _f, δ _IThe expression integer factor, δ _fThe expression decimal factor, δ _I* Δ B represents integer frequency bias, δ _f* Δ B represents decimal frequency bias.Therefore, as long as estimate integer δ _I, just can obtain integer frequency bias δ _I* Δ B.

The length of note frame head PN sequence is P baseband sample point (the concrete value of P is relevant with the frame head mode of transmitting terminal emission, is one of 420 or 945 two-values); Thick sync bit (this thick sync bit has identified the starting point of the frame head PN sequence) index that the synchronization acquistion treatment step obtains before the note is I _CoarseThe requirement that the note system docking is received the maximum delay expansion of machine is L _{Ds, max}

A, according to the frame head mode known one of (PN420 frame head mode and PN945 frame head mode the two), the arbitrary local frame head PN sequence that has phase change of choosing corresponding frame head mode is as secondary processing sequence; And from received signal, choose Q section received signal sequence as pending data sequence, the length of every segment data sequence is 2L _{Ds, max}+ P data sample, the selection principle of the pending data sequence of this Q section be, exists under the precondition that the PN sequence phase changes in hypothesis, and the final selected pending data sequence of Q section can be distinguished one by one corresponding to all Q PN sequence phases.For PN420 frame head mode Q=225, for PN945 frame head mode Q=200.

Wherein, secondary processing sequence is designated as s _{Pn, q}(n), length is P, and wherein the span of index n is 0～P-1; Q=1,2 ..., the arbitrary integer among the Q-1 is represented the sequence number of the local frame head PN sequence of corresponding frame head mode, selecting the sequence number that do not comprise as secondary processing sequence is 0---and be the local frame head PN sequence that phase place does not change; After q is chosen to be above any numerical value, in this subsynchronous signal processing, do not change.

Wherein, secondary processing sequence can be chosen from the read only memory ROM of receiver, also can utilize LFSR to generate in real time, no matter how to obtain, this secondary processing sequence all must be corresponding frame head mode have one of local frame head PN sequence of phase change.

Wherein, described received signal r (n), n=0,1,2 ... can be through the decimal frequency bias compensation.

Wherein, the length of the pending data sequence of each section is 2L _{Ds, max}+ P data sample is designated as r _{Pn, w}(n), w is the sequence number of pending data sequence, and span is w=0,1,2 ..., Q-1.

Wherein, the concrete system of selection of the pending data sequence of a kind of each section can be: first Continuous Selection 2L from received signal r (n) _{Ds, max}+ P data sample is as the 0th section pending data sequence r _{Pn, 0}(n), wherein the span of the index n of sample of signal is I _{Coarse, 0}-L _{Ds, max}～I _{Coarse, 0}+ L _{Ds, max}+ P-1 (wherein, I _{Coare, 0}=I _Coarse); Then, with I _CoarseIndex value postpones the individual base band data point of P+D (D=3780), note I _{Coarse, 1}=I _Coarse+ P+D, Continuous Selection 2L again _{Ds, max}+ P data sample is as the 1st section pending data sequence r _{Pn, 1}(n), wherein the span of the index n of sample of signal is I _{Coarse, 1}-L _{Ds, max}～I _{Coarse, 1}+ L _{Ds, max}+ P-1; By that analogy, only need be updated periodically index value I _{Coarse, w}, can select the pending data sequence of all Q sections, the span of the index n of sample of signal is I in the pending data sequence of each section _{Coarse, w}-L _{Ds, max}～I _{Coarse, w}+ L _{Ds, max}+ P-1.This system of selection is to be the method that a superframe was selected in (125 milliseconds) time, wherein index value I in length _{Coarse, w}Update cycle equal the length of signal frame; Also can be with 125 milliseconds of superframes as index value I _{Coarse, w}Update cycle; Perhaps signal frame length and superframe length are united use, after treatment, as index value I _{Coarse, w}Update cycle; Index value I _{Coarse, w}Update cycle, just transmitting terminal repeated to send the frame head PN sequence of out of phase the time cycle.Though after employing this method, estimate that frame head phase place and used time of frequency deviation wants the length of a superframe at least, because interweaving of carrying out of subsequent step is consuming time more, though therefore estimating step ratio consuming time was originally long, from whole receiving course, but do not cause time delay, do not influence overall performance.

In specific implementation, these pending data sequences can be stored in the random access memory ram, can certainly periodically select current received signal sequence for use and do not store, thus can conserve storage.

B, the pending data sequence of Q section is carried out following operation respectively:

Treat the deal with data sequence and carry out the integer frequency bias compensation, the integer frequency bias that is compensated is k * Δ B, and wherein, integer factor k is taken as respectively-δ _{I, max}To+δ _{I, max}In each integer, comprise-δ _{I, max}With+δ _{I, max} $\mathrm{\ΔB}=\frac{F}{N+L}\mathrm{Hz},$ F is the baseband sampling rate of system, is 165 for PN420 frame head mode N, and L is 90; For PN420 frame head mode N is 434, and L is 77; Receiver to the area requirement of integer frequency bias is-δ _{I, max}* Δ B arrives+δ _{I, max}* Δ B comprises-δ _{I, max}* Δ B and+δ _{I, max}* Δ B; δ wherein _{I, max}＞0, be integer, R=2 δ _{I, max}+ 1;

Pending sequence when k is got different value after the compensation is carried out cross-correlation operation with secondary processing sequence respectively, obtains R correlated series, further obtains the power sequence of each correlated series.

As can be seen, k can get R value altogether, and therefore every section deal with data all can obtain R power sequence, can obtain R * Q power sequence altogether; Find out the maximum power value P in this R * Q power sequence _{Corr, max}And the average power P of the power sequence at place _{Corr, avg}And this maximum power value P _{Corr, max}Corresponding sample point index I in power sequence _{Corr, peak}, and obtain this maximum power value P _{Corr, max}The pending data sequence of Shi Suoyong and integer factor δ _{I, corr}

Wherein, to sequence r _{Pn, w}(n) do the integer frequency bias compensation, a kind of concrete implementation method can be expressed as follows: r is carried out on sample-by-sample ground _{Pn, w}(n) exp (j2 π k Δ Bn/F) multiply operation, and note is through integer frequency bias sequence after compensation r _{Pn, w}(n) be r _{Pn, w, 2}(n), wherein exp (x) represents e ^xThe operation, e=2.71828..., j represent plural indicator, F represents the baseband sampling rate, can but be not limited to 7.56MHz.

Wherein, to sequence r _{Pn, w, 2}(n), n=I _{Coarse, w}-L _{Ds, max}～I _{Coarse, w}+ L _{Ds, max}+ P-1 and sequence S _{Pn, q}(m), m=0～P-1 carries out cross-correlation operation by following formula, obtains correlated series, is designated as sequence S _Corr(l), l=0,1 ..., 2L _{Ds, max}:

$s_{\mathrm{corr}}\left(l\right)=\underset{m=0}{\overset{P-1}{\mathrm{\Σ}}}\mathrm{conj}\left(s_{\mathrm{pn},q}\left(m\right)\right)\·r_{\mathrm{pn},w,2}(I_{\mathrm{coarse},w}-L_{\mathrm{ds},\max }+l+m)$

The operation of conj () expression complex conjugate.

Wherein, correlated series s _Corr(l), l=0,1 ..., 2L _{Ds, max}Power sequence P _Corr(l)=| s _Corr(l) | ², l=0,1 ..., 2L _{Ds, max}

Wherein, power sequence P _Corr(l), l=0,1 ..., 2L _{Ds, max}Maximum power value P _{Corr, max} ^tFor:

$P_{\mathrm{corr},\max }^t={\max }_{l=0}^{2\·L_{\mathrm{ds},\max }}\left(P_{\mathrm{corr}}\left(l\right)\right)$

This maximum power value P _{Corr, max} ^tCorresponding power sequence sample point index $I_{\mathrm{corr},\mathrm{peak}}^t=\arg \max \left(P_{\mathrm{corr}}\left(l\right)\right),$ The average power of power sequence $P_{\mathrm{corr},\mathrm{avg}}^t=\mathrm{mean}\left(P_{\mathrm{corr}}\left(l\right)\right);$ Wherein maxima operation is got in max () expression, and the operation of maximum corresponding index value is got in argmax () expression, and mean () represents to average operation.

Wherein, also can be that each k value is carried out following operation: each pending sequence is carried out the integer frequency bias compensation, and the integer frequency bias that is compensated be k * Δ B; Cross-correlation operation is carried out with secondary processing sequence in the compensation back, obtains Q correlated series, further obtains the power sequence of these correlated serieses.Operation is the same with the aforesaid operations result, only slightly variant on the process like this.

Wherein, also can utilize range value to wait the judgement of carrying out correlation, and the power that is not limited to is above judged, concrete deterministic process and said process are similar, repeat no more here.

C, renewal receiver state enter tracking mode; Determine δ _{I, corr}* Δ B is integer frequency bias; Determine I _{Coarse, W}+ I _{Corr, peak}-L _{Ds, max}Be the fine synchronization location index of acquisition;

Judge P _{Corr, max}Whether greater than or more than or equal to T _Power* P _{Crr, avg}, T wherein _PowerBe the power factor threshold value, a concrete value can be 64; If be to adopt range value to judge, then here for the amplitude factor threshold T is set _Amp, wherein $T_{\mathrm{amp}}=\sqrt{T_{\mathrm{power}}};$

If show that then there is phase change in frame head PN sequence, and found local PN sequence s _{Pn, q}(n) Dui Ying frame head data section obtains maximum power value P _{Corr, max}The phase place of the pending data sequence correspondence of Shi Suoyong is local sequence s _{Pn, q}(n) Dui Ying phase place.

Otherwise, showing that then there is not phase change in frame head PN sequence, all frame head PN sequences all adopt the PN initial phase of sequence number 0.

Need to prove that the parameter that all in the such scheme are associated is provided with all to be needed to determine under the precondition of carrying out sufficient data simulation.

The estimation unit of a kind of receiver frame head phase place and integer frequency bias as shown in Figure 8, comprising:

The secondary processing sequence generation module is used to select local PN sequence to send to cross-correlation module;

Cross-correlation module is used to receive sequence after compensation and local PN sequence, and two sequences are carried out cross-correlation operation, and cross correlation results is sent to Executive Module.

Executive Module, be used for behind the frame head mode of thick sync bit that obtains frame and transmitting terminal emission, various frame head phase places difference under generation and this frame head mode are the received signal sequence one to one, each received signal sequence is carried out the integer frequency bias compensation according to each integer frequency bias value respectively, and the received signal sequence after will compensating sends to cross-correlation module; And the pairing frame head phase place of result that correlation in Q * R kind cross correlation results is best and integer frequency bias value are as frame head phase place that estimates and the output of integer frequency bias value; Wherein Q is the species number of frame head phase place, the integer frequency bias value number of R for occurring.

For the DTMB system, the note receiver to the area requirement of integer frequency bias is-δ _{I, max}* Δ B～+ δ _{I, max}* Δ B, wherein δ _{I, max}＞0, be integer, $\mathrm{\ΔB}=\frac{F}{N+L}\mathrm{Hz},$ F is the baseband sampling rate of system, and N and L are as mentioned before; The integer frequency bias value number R=2 δ that then may occur _{I, max}+ 1.

Wherein, the secondary processing sequence generation module selects local PN sequence specifically can be meant:

The secondary processing sequence generation module is according to the frame head mode known one of (PN420 frame head mode and PN945 frame head mode the two), and the arbitrary local frame head PN sequence that has phase change of choosing corresponding frame head mode is as secondary processing sequence s _{Pn, q}(n).

Wherein, s _{Pn, q}(n) length is P, and wherein the span of index n is 0～P-1; Q=1,2 ..., the arbitrary integer among the Q-1 is represented the sequence number of the local frame head PN sequence of corresponding frame head mode, selecting the sequence number that do not comprise as secondary processing sequence is 0---and be the local frame head PN sequence that phase place does not change; After q is chosen to be above any numerical value, in this subsynchronous signal processing, do not change.

Wherein, the secondary processing sequence generation module can be chosen local PN sequence from receiver ROM, also can utilize LFSR to generate the local PN sequence of selection in real time.

Wherein, Executive Module specifically can comprise:

Pending data sequence generates submodule, is used for choosing Q segment data sequence as pending data sequence r from received signal _{Pn, w}(n), the length of every segment data sequence is 2L _{Ds, max}+ P data sample, the pending data sequence of this Q section exist in hypothesis under the precondition of PN sequence phase variation, respectively one by one corresponding to all Q PN sequence phases; And the corresponding pending data sequence of transmission compensates submodule to integer frequency bias under the indication of control submodule;

Wherein, described received signal r (n), n=0,1,2 ... can be through the decimal frequency bias compensation.

Wherein, pending data sequence generates submodule and chooses the pending data sequence of each section and specifically can be meant: pending data sequence generates submodule first Continuous Selection 2L from received signal r (n) _{Ds, max}+ P data sample is as the 0th section pending data sequence r _{Pn, 0}(n), wherein the span of the index n of sample of signal is I _{Coarse, 0}-L _{Ds, max}～I _{Coarse, 0}+ L _{Ds, max}+ P-1 (wherein, I _{Coarse, 0}=I _Coarse); Then, with I _CoarseIndex value postpones P+D, and (in the DTMB system, D=3780) individual base band data point is remembered I _{Coarse, 1}=I _Coarse+ P+D, Continuous Selection 2L again _{Ds, max}+ P data sample is as the 1st section pending data sequence r _{Pn, 1}(n), wherein the span of the index n of sample of signal is I _{Coarse, 1}-L _{Ds, max}～I _{Coarse, 1}+ L _{Ds, max}+ P-1; By that analogy, only need be updated periodically index value I _{Coarse, w}, can select the pending data sequence of all Q sections, the span of the index n of sample of signal is I in the pending data sequence of each section _{Coarse, w}-L _{Ds, max}～I _{Coarse, w}+ L _{Ds, max}+ P-1.

Wherein, pending data sequence generates submodule can comprise RAM, is used to preserve these pending data sequences.

Integer frequency bias compensation submodule is used to receive the integer frequency bias value that the control submodule provides and treats the deal with data sequence and generates the pending data sequence that submodule sends and carry out the integer frequency bias compensation, and sequence after compensation is sent to cross-correlation module;

Wherein, integer frequency bias compensation submodule carries out the integer frequency bias compensation and specifically can be meant: integer frequency bias compensation submodule sample-by-sample ground execution r _{Pn, w}(n) exp (j2 π k Δ Bn/F) multiply operation, and note is through integer frequency bias sequence after compensation r _{Pn, w}(n) be r _{Pn, w, 2}(n), wherein exp (x) represents e ^xThe operation, e=2.71828..., j represent plural indicator, F represents the baseband sampling rate, can but be not limited to 7.56MHz.

The control submodule is used for beginning to indicate pending data sequence to generate submodule and sending one section pending data sequence behind the frame head mode of thick sync bit that obtains frame and transmitting terminal emission; Every indication sends one section pending data sequence, and just sending different R integer frequency bias value respectively compensates submodule to integer frequency bias; After all integer frequency bias values all send, indicate pending data sequence to generate submodule again and send the pending data sequence of next section, all send up to the pending data sequence of Q section.And the correlated results s that receives cross-correlation module _CorrAnd obtain its power sequence P (l), _Corr(l)=| s _Corr(l) | ², l=0,1 ..., 2L _{Ds, max}And find out R * Q the maximum power value P in the power sequence _{Corr, max}And the average power P of the power sequence at place _{Corr, avg}And this maximum power value P _{Corr, max}Corresponding sample point index I in power sequence _{Corr, pesk}, and obtain this maximum power value P _{Corr, max}The pending data sequence of Shi Suoyong and integer frequency bias value F; And the renewal receiver state is a tracking mode; With integer frequency bias value F as integer frequency bias, I _{Coarse, W}+ I _{Corr, peak}-L _{Ds, max}As the fine synchronization location index output that obtains; And judgement P _{Corr, max}Whether more than or equal to T _Power* P _{Corr, avg}, if, then with maximum power value P _{Corr, max}The phase place of the pending data sequence correspondence of Shi Suoyong is as local sequence s _{Pn, q}(n) Dui Ying phase place; Otherwise think that there is not phase change in frame head PN sequence.

Wherein, also can utilize range value to wait the judgement of carrying out correlation, and the power that is not limited to is above judged, concrete deterministic process and said process are similar, repeat no more here.

Wherein, control the power sequence P that submodule obtains _Corr(l) maximum power value is P _{Corr, max} ^t:

$P_{\mathrm{corr},\max }^t={\max }_{l=0}^{2\·L_{\mathrm{ds},\max }}\left(P_{\mathrm{corr}}\left(l\right)\right)$

This maximum power value P _{Corr, max} ^tCorresponding power sequence sample point index $I_{\mathrm{corr},\mathrm{peak}}^t=\arg \max \left(P_{\mathrm{corr}}\left(l\right)\right),$ The average power of power sequence $P_{\mathrm{corr},\mathrm{avg}}^t=\mathrm{mean}\left(P_{\mathrm{corr}}\left(l\right)\right).$

For the DTMB system, the control integer frequency bias value that submodule sent is k * Δ B, and integer factor k is taken as respectively-δ _{I, max}To+δ _{I, max}In each integer, comprise-δ _{I, max}With+δ _{I, max}Obtain maximum power value P _{Corr, max}The integer factor δ of Shi Suoyong _{I, corr}(also can obtain integer frequency bias value F); With δ _{I, corr}* Δ B (being integer frequency bias value F) is as integer frequency bias.

For the DTMB system, the control submodule can also comprise:

The maximum power value register is used to preserve the maximum power value P of all correlated serieses _{Corr, max}, its initial value is changed to 0;

The average power value register is used for preserving corresponding to maximum power value P _{Corr, max}The average power content P of correlated series _{Corr, avg}, its initial value is changed to 0;

Sample point index value register is used to preserve maximum power value P _{Corr, max}Sample point index value I in the corresponding correlated series _{Corr, peak}, its initial value is changed to 0;

The integer factor register is used to preserve the integer factor δ of integer frequency bias correspondence _{I, corr}, its initial value is changed to 0;

The frame head data serial number register is used to preserve local PN sequence s _{Pn, q}(n) the sequence number W of Dui Ying frame head data, its initial value is changed to 0;

The control submodule is found out R * Q the maximum power value P in the power sequence _{Corr, max}And the average power P of the power sequence at place _{Corr, avg}And this maximum power value P _{Corr, max}Corresponding sample point index I in power sequence _{Corr, peak}, and obtain this maximum power value P _{Corr, max}The pending data sequence of Shi Suoyong and integer frequency bias value F specifically can be meant:

Maximum power value for each power sequence is P _{Corr, max} ^t, the control submodule is judged P _{Corr, max} ^tWhether greater than P _{Corr, max}If, greater than, then with P _{Corr, max} ^tBe kept at the maximum power value register, with P _{Corr, avg} ^tBe kept at the average power value register, with I _{Corr, peak} ^tBe kept at sample point index value register, k is kept at the integer factor register, the sequence number w of pending data sequence is kept at the frame head data serial number register; Otherwise, then do not carry out any operation.

Wherein, the cross-correlation submodule is to sequence r _{Pn, w, 2}(n), n=I _{Coarse, w}-L _{Ds, max}～I _{Coarse, w}+ L _{Ds, max}+ P-1 and sequence s _{Pn, q}(m), m=0～P-1 carries out cross-correlation operation by following formula, obtains correlated series s _Corr(l), l=0,1 ..., 2L _{Ds, max}:

$s_{\mathrm{corr}}\left(l\right)=\underset{m=0}{\overset{P-1}{\mathrm{\Σ}}}\mathrm{conj}\left(s_{\mathrm{pn},q}\left(m\right)\right)\·r_{\mathrm{pn},w,2}(I_{\mathrm{coarse},w}-L_{\mathrm{ds},\max }+l+m)$

The operation of conj () expression complex conjugate.

Control submodule in other system also can comprise register, with the difference of above-mentioned realization only is: the integer factor register is become the integer frequency bias register that is used to preserve integer frequency bias, at P _{Corr, max} ^tGreater than P _{Corr, max}The time, the integer frequency bias value that is adopted is kept at the integer frequency bias register.

The implication of each parameter and other realize that details is with described in the method.

Certainly; the present invention also can have other various embodiments; under the situation that does not deviate from spirit of the present invention and essence thereof; those of ordinary skill in the art work as can make various corresponding changes and distortion according to the present invention, but these corresponding changes and distortion all should belong to the protection range of claim of the present invention.

Claims (17)

1, the method for estimation of a kind of receiver frame head phase place and integer frequency bias comprises:

Behind the frame head mode of the thick sync bit of acquisition frame and transmitting terminal emission, frame head phase place and carrier wave frequency deviation gang are estimated, obtained thin sync bit when estimating the frame head phase place.

2, method of estimation as claimed in claim 1 is characterized in that, specifically comprises:

Behind the frame head mode of the thick sync bit of acquisition frame and transmitting terminal emission, obtain with this frame head mode under various frame head phase places received signal sequence one to one respectively, after each received signal sequence is carried out the integer frequency bias compensation according to each integer frequency bias value respectively, carry out cross-correlation operation with the local PN sequence of selecting, obtain Q * R kind cross correlation results altogether, wherein Q is the species number of frame head phase place, the integer frequency bias value number of R for occurring; Pairing frame head phase place of result that correlation is best and integer frequency bias value are frame head phase place and the integer frequency bias value that estimates.

3, method of estimation as claimed in claim 2 is characterized in that, obtain with this frame head mode under various frame head phase places respectively one to one the received signal sequence specifically be meant:

From received signal, choose Q section received signal sequence as pending data sequence r _{Pn, w}(n), w is the sequence number of pending data sequence; The length of every segment data sequence is 2L _{Ds, max}+ P data sample, the pending data sequence of this Q section is respectively one by one corresponding to all Q PN sequence phases; P is the length of frame head PN sequence; L _{Ds, max}Receive the requirement of the maximum delay expansion of machine for system docking.

4, method of estimation as claimed in claim 3 is characterized in that, the concrete system of selection of the pending data sequence of each section comprises:

The span of the index n of sample of signal is I in the pending data sequence of each section _{Coarse, w}-L _{Ds, max}To I _{Coarse, w}+ L _{Ds, max}Each integer of+P-1 comprises I _{Coarse, w}-L _{Ds, max}And I _{Coarse, w}+ L _{Ds, max}+ P-1; I _{Coarse, w}=I _{Coarse, w-1}+ P+D, I _{Coarse, 0}=I _Coarse, I _CoarseBe the index of thick sync bit, D is the frame data length, D=3780 in the DTMB system; I _{Coarse, w}Update cycle be the cycle of transmitting terminal when repeating to send the frame head PN sequence of out of phase.

5, method of estimation as claimed in claim 2 is characterized in that:

The described local PN sequence of selecting is a secondary processing sequence, and length is P, and P is the length of frame head PN sequence, is arbitrary local frame head PN sequence corresponding frame head mode, that phase place changes.

6, method of estimation as claimed in claim 5 is characterized in that, each received signal sequence is carried out after the integer frequency bias compensation according to each integer frequency bias value respectively and the local PN sequence selected is carried out cross-correlation operation and specifically comprised:

The pending data sequence of Q section is carried out following operation respectively:

Treat the deal with data sequence and carry out the integer frequency bias compensation by different integer frequency bias values;

For carrying out cross-correlation operation with secondary processing sequence respectively according to the pending sequence after the different integer frequency bias value compensation.

7, method of estimation as claimed in claim 6 is characterized in that, for the DTMB system:

The integer frequency bias that is compensated is k * Δ B, and wherein, integer factor k is taken as respectively-δ _{I, max}To+δ _{I, max}In each integer, comprise-δ _{I, max}With+δ _{I, max}

$\mathrm{\ΔB}=\frac{F}{N+L}\mathrm{Hz},$ F is the baseband sampling rate of system, is 165 for PN420 frame head mode N, and L is 90; For PN420 frame head mode N is 434, and L is 77; Receiver to the area requirement of integer frequency bias is-δ _{I, max}* Δ B arrives+δ _{I, max}* Δ B comprises-δ _{I, max}* Δ B and+δ _{I, max}* Δ B, wherein δ _{I, max}＞0, be integer, R=2 δ _{I, max}+ 1.

8, method of estimation as claimed in claim 6 is characterized in that, pairing frame head phase place of result that correlation is best and integer frequency bias value are that frame head phase place and the integer frequency bias value that estimates is meant:

Correlated series for cross-correlation operation obtains further obtains its power sequence, can obtain R * Q power sequence altogether; Find out the maximum power value P in this R * Q power sequence _{Corr, max}And the average power P of the power sequence at place _{Corr, avg}And this maximum power value P _{Corr, max}Corresponding sample point index I in power sequence _{Corr, peak}, and obtain this maximum power value P _{Corr, max}The pending data sequence of Shi Suoyong and integer frequency bias value F;

Upgrade receiver state, enter tracking mode; Determine that F is integer frequency bias; Determine I _{Coarse, W}+ I _{Corr, peak}-L _{Ds, max}Be the fine synchronization location index of acquisition;

Judge P _{Corr, max}Whether greater than or more than or equal to T _Power* P _{Corr, avg}, T wherein _PowerBe the power factor threshold value, if then obtain maximum power value P _{Corr, max}The phase place of the pending data sequence correspondence of Shi Suoyong is local sequence s _{Pn, q}(n) Dui Ying phase place, otherwise, show that then there is not phase change in frame head PN sequence.

9, method of estimation as claimed in claim 8 is characterized in that:

For DTMB system, T _Power=64.

10, the estimation unit of a kind of receiver frame head phase place and integer frequency bias is characterized in that, comprising:

The secondary processing sequence generation module is used to select local PN sequence to send to cross-correlation module;

Cross-correlation module is used to receive sequence after compensation and local PN sequence, and two sequences are carried out cross-correlation operation, and cross correlation results is sent to Executive Module.

Executive Module, be used for behind the frame head mode of thick sync bit that obtains frame and transmitting terminal emission, various frame head phase places difference under generation and this frame head mode are the received signal sequence one to one, each received signal sequence is carried out the integer frequency bias compensation according to each integer frequency bias value respectively, and the received signal sequence after will compensating sends to cross-correlation module; And the pairing frame head phase place of result that correlation in Q * R kind cross correlation results is best and integer frequency bias value are as frame head phase place that estimates and the output of integer frequency bias value; Wherein Q is the species number of frame head phase place, the integer frequency bias value number of R for occurring.

11, estimation unit as claimed in claim 10 is characterized in that, the secondary processing sequence generation module selects local PN sequence specifically to be meant:

The secondary processing sequence generation module is according to the frame head mode of having known, the arbitrary local frame head PN sequence that has phase change of choosing corresponding frame head mode is as secondary processing sequence.

12, estimation unit as claimed in claim 10 is characterized in that, Executive Module specifically comprises:

Pending data sequence generates submodule, is used for choosing Q segment data sequence as pending data sequence r from received signal _{Pn, w}(n), the length of every segment data sequence is 2L _{Ds, max}+ P data sample, the pending data sequence of this Q section is respectively one by one corresponding to all Q PN sequence phases; And the corresponding pending data sequence of transmission compensates submodule to integer frequency bias under the indication of control submodule;

Integer frequency bias compensation submodule is used to receive the integer frequency bias value that control module provides and treats the deal with data sequence and generates the pending data sequence that submodule sends and carry out the integer frequency bias compensation, and sequence after compensation is sent to cross-correlation module;

The control submodule is used for beginning to indicate pending data sequence to generate submodule and sending one section pending data sequence behind the frame head mode of thick sync bit that obtains frame and transmitting terminal emission; Every indication sends one section, and just sending different R integer frequency bias value respectively compensates submodule to integer frequency bias; After all integer frequency bias values all send, indicate pending data sequence to generate submodule again and send the pending data sequence of next section, all send up to the pending data sequence of Q section; And the correlated results that receives cross-correlation module, and obtain its power sequence; And find out R * Q the maximum power value P in the power sequence _{Corr, max}And the average power P of the power sequence at place _{Corr, avg}With this maximum power value P _{Corr, max}Corresponding sample point index I in power sequence _{Corr, peak}, and obtain this maximum power value P _{Corr, max}The pending data sequence of Shi Suoyong and integer frequency bias value F; And the renewal receiver state is a tracking mode; With F as integer frequency bias, I _{Coarse, W}+ I _{Corr, peak}-L _{Ds, max}As the fine synchronization location index output that obtains; And judgement P _{Corr, max}Whether more than or equal to T _Power* P _{Corr, avg}, if, then with maximum power value P _{Corr, max}The phase place of the pending data sequence correspondence of Shi Suoyong is as local sequence s _{Pn, q}(n) Dui Ying phase place; Otherwise think that there is not phase change in frame head PN sequence;

Wherein, Q is the species number of frame head phase place, and P is the length of frame head PN sequence; L _{Ds, max}Receive the requirement of the maximum delay expansion of machine for system docking; I _CoarseIndex for thick sync bit.

13, estimation unit as claimed in claim 12 is characterized in that:

The span of the index n of sample of signal is I in the pending data sequence of each section that pending data sequence generation submodule is chosen _{Coarse, w}-L _{Ds, max}To I _{Coarse, w}+ L _{Ds, max}Each integer of+P-1 comprises I _{Coarse, w}-L _{Ds, max}And I _{Coarse, w}+ L _{Ds, max}+ P-1, I _{Coarse, w}=I _{Coarse, w-1}+ P+D, I _{Coarse, 0}=I _Coarse, I _CoarseBe the index of thick sync bit, D is the frame data length, D=3780 in the DTMB system; I _{Coarse, w}Update cycle be the cycle of transmitting terminal when repeating to send the frame head PN sequence of out of phase.

14, estimation unit as claimed in claim 12 is characterized in that, for the DTMB system:

Q=225 when adopting the PN420 frame head mode, Q=200 when adopting the PN945 frame head mode;

Receiver to the area requirement of integer frequency bias is-δ _{I, max}* Δ B arrives+δ _{I, max}* Δ B comprises-δ _{I, max}* Δ B and+δ _{I, max}* Δ B, wherein δ _{I, max}＞0, be integer, R=2 δ _{I, max}+ 1; $\mathrm{\ΔB}=\frac{F}{N+L}\mathrm{Hz},$ F is the baseband sampling rate of system, is 165 for PN420 frame head mode N, and L is 90; For PN420 frame head mode N is 434, and L is 77;

The control integer frequency bias value that submodule sent is k * Δ B, and integer factor k is taken as respectively-δ _{I, max}To+δ _{I, max}In each integer, comprise-δ _{I, max}With+δ _{I, max}

15, estimation unit as claimed in claim 14 is characterized in that, the control submodule also comprises:

The maximum power value register is used to preserve the maximum power value P of all correlated serieses _{Corr, max}, its initial value is changed to 0;

The average power value register is used for preserving corresponding to maximum power value P _{Corr, max}The average power content P of correlated series _{Corr, avg}, its initial value is changed to 0;

Sample point index value register is used to preserve maximum power value P _{Corr, max}Sample point index value I in the corresponding correlated series _{Corr, peak}, its initial value is changed to 0;

The integer factor register is used to preserve the integer factor δ of integer frequency bias correspondence _{I, corr}, its initial value is changed to 0;

The frame head data serial number register is used to preserve local PN sequence s _{Pn, q}(n) the sequence number W of Dui Ying frame head data, its initial value is changed to 0;

16, estimation unit as claimed in claim 15 is characterized in that, the control submodule is found out R * Q the maximum power value P in the power sequence _{Corr, max}And the average power P of the power sequence at place _{Corr, avg}And this maximum power value P _{Corr, max}Corresponding sample point index I in power sequence _{Corr, peak}, and obtain this maximum power value P _{Corr, max}The pending data sequence of Shi Suoyong and integer factor δ _{I, corr}Specifically refer to:

Maximum power value for each power sequence is P _{Corr, max} ^t, the control submodule is judged P _{Corr, max} ^tWhether greater than P _{Corr, max}If, greater than, then with P _{Corr, max} ^tBe kept at the maximum power value register, with P _{Corr, avg} ^tBe kept at the average power value register, with I _{Corr, peak} ^tBe kept at sample point index value register, k is kept at the integer factor register, the sequence number w of pending data sequence is kept at the frame head data serial number register; Otherwise, then do not carry out any operation.

17, as each described estimation unit of claim 12 to 16, it is characterized in that:

For DTMB system, T _Power=64.

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