CN101304402B

CN101304402B - Locking method and system for correlation peak value process

Info

Publication number: CN101304402B
Application number: CN2008101158178A
Authority: CN
Inventors: 洪波
Original assignee: Beijing Haier IC Design Co Ltd
Current assignee: Beijing Haier IC Design Co Ltd
Priority date: 2008-06-30
Filing date: 2008-06-30
Publication date: 2011-08-31
Anticipated expiration: 2028-06-30
Also published as: CN101304402A

Abstract

The invention discloses a locking method and a system in the treatment of the correlation peak value. The system comprises a correlation unit which correlates the received data and the local PN sequences, a correlation value treatment unit which calculates the pre-selection peak value and the pre-selection peak position of the current frame according to correlation values and a peak position matching unit; wherein, the peak position matching unit comprises a peak displacement predictive module which calculates the peak displacement of the current frame on the basis of the pre-selection peak value position of the former frame and/or predicts the predictive peak value position of the current frame, a matching module which matches the peak displacement/the predictive peak position and the peak value positions of the current frames and a matching detector module which combines the matched results together by using the Boolean OR operator and outputs the locking signals. The method and the system have good stability and better solve the locking problem in the treatment of the correlation peak of the synchronization signal frames in the digital communication.

Description

Locking means and system thereof during a kind of correlation peak is handled

Technical field

The present invention relates to method synchronous in a kind of digital communication and system thereof, locking means and system thereof during especially a kind of correlation peak is handled.

Background technology

In digital communication system, extremely important synchronously.Data need redefine the data initial point position through after the long-time transmission at receiving terminal; Because not matching of receiving terminal sampling clock and carrier frequency and transmitting terminal need be carried out carrier wave and sampling clock compensation to data at receiving terminal.Can not recover accurately receiving data synchronously accurately.

Estimate at a variety of algorithms synchronously.For utilizing local PN sequence to carry out synchronous system, comprise China Digital TV ground standard (GB 20600-2006) receiver synchro system, frame synchronization is generally finished by receiving the relevant searching with local sequence of data peak value; Sampling clock is finished by the difference of 1/2 sampling instant (character rate) about peak value synchronously.Correlation peak plays important effect in this synchro system, its stability and reliability all will determine the quality of synchronized result performance.

In the processing of correlation peak, to lock system in certain stage, it is stable that the generation direct relation correlation peak of this locking signal is handled.

Summary of the invention

The object of the present invention is to provide locking means and system thereof in a kind of correlation peak processing, can better help the processing of signal frame correlation peak.

According to a first aspect of the invention, provide locking means in a kind of correlation peak processing, may further comprise the steps:

It is relevant with local PN sequence to receive data;

Correlation is handled, obtained each peak value and peak and calculate the preliminary election peak value and the preliminary election peak of present frame;

It is characterized in that described method is further comprising the steps of:

Calculate the peak displacement of present frame based on the preliminary election peak of preceding frame, and/or estimate the peak of estimating of present frame;

The peak displacement of present frame and/or estimate peak and each peak of present frame is mated;

Result to coupling carries out matching detection, to produce locking signal;

Wherein, following steps are passed through in the calculating of the preliminary election peak value of described present frame and preliminary election peak:

Whether each peak correlation value of more same frame surpasses preset threshold with the ratio of last correlation peaks, if surpass, is the temporary transient assignment of this correlation peaks the preliminary election peak value then;

As not surpassing, continue the comparison of next peak value;

All peak values to this frame all compare, up to final definite preliminary election peak value and preliminary election peak.

Preferably, further comprising the steps of before the generation of described locking signal:

According to the matching result that matching detection arrives, put letter and detect;

Detect to satisfy when putting the letter threshold value output locking signal when putting letter.

According to a second aspect of the invention, provide locking system in a kind of correlation peak processing, having comprised: correlation unit, carry out receive data relevant with local PN sequence; The correlation processing unit is according to the preliminary election peak value and the preliminary election peak of correlated results calculating present frame; It is characterized in that described system also comprises the peak matching unit, comprising:

Peak displacement is estimated module, calculates the peak displacement of present frame based on the preliminary election peak of preceding frame, and/or estimates the peak of estimating of present frame;

Description of drawings

Matching module is peak displacement and/or estimate peak and each peak of present frame is mated;

The matching detector module is carried out matching detection to matching result, with the output locking signal;

As not surpassing, continue the comparison of next peak value;

Embodiment

Preferably, described peak matching unit also comprises puts the letter detection module, wherein: according to the matching result that matching detection arrives, put letter and detect; Detect to satisfy when putting the letter threshold value when putting letter, export locking signal then.

The invention provides locking means and system thereof in a kind of new correlation peak processing, have stability and reliability better.

Below with reference to accompanying drawings specific embodiments of the present invention is described in detail, wherein:

Fig. 1 is a system construction drawing of the present invention;

Fig. 2 is a peak value matching unit structure chart of the present invention;

Fig. 3 is a sampling clock sync peaks processing unit structure chart of the present invention; And

Fig. 4 is a kind of channel impulse response functional arrangement of the present invention.

Specify correlation peak of the present invention handle in before locking means and the system, at first wherein relevant parameter is described.

If every frame frame length is N, i corresponding signal frame correlation is

p _i，0，p _i，1，p _i，2，…p _i，N-1。

Preliminary election peak value p _{I, peak}And at preliminary election peak I _{I, peak}Be defined as follows:

p _i，peak＝p _i，0；

I _i，peak＝0；

for(j＝1；j＜＝N；j++)

{

if(p _i，j＞＝A·p _i，j-1)

{

p _i，peak＝p _i，j；

I _i，peak＝j；

}

?}

Wherein A is the preset threshold coefficient, and the value scope that it adopted is (1,3).

I _{I, max1}, I _{I, max2}, I _{I, max3}... be respectively i signal frame peak-peak position, second largest peak, the third-largest peak .....

I _{I, sfo}Be that the sampling clock synchronization scenario is with reference to peak.

Idx is correlation p _{I, idx}Corresponding position.

I _{I, fsyn}Be that the frame synchronization scheme is with reference to peak.

Fig. 1 illustrates the structure chart of the synchronous correlation peak treatment system of the present invention.As shown in Figure 1, this system comprises correlation unit, correlation processing unit, peak matching unit, sampling clock sync peaks processing unit and frame synchronization peak value processing unit.

Correlation unit carries out reception data and local PN sequence relevant, obtains signal frame correlation p _{I, idx}And position idx.

The correlation processing unit is handled correlation, draws preliminary election peak value p _{I, peak}And position, and I _{I, max1}, I _{I, max2}, I _{I, max3}...Preliminary election peak value p wherein _{I, peak}It is each peak I _{I, max1}, I _{I, max2}, I _{I, max3}... in one.

Then, correlation processing unit output p _{I, peak}, I _{I, peak}Give sampling clock sync peaks processing unit; Output I _{I, peak}, I _{I, max1}, I _{I, max2}, I _{I, max3}... give the peak matching unit; Output I _{I, peak}Give frame synchronization peak value processing unit.

The peak matching unit calculates the peak displacement of present frame according to the preliminary election peak of preceding frame, and/or estimate the peak of estimating of present frame, and will carry out matching judgment in conjunction with each peak in the present frame, give sampling clock sync peaks processing unit and frame synchronization peak value processing unit according to match condition output locking signal then.

Sampling clock sync peaks processing unit is according to the p of input _{I, peak}, I _{I, peak}, p _{I, idx}, idx and lock signal output peak I _{I, sfo}, I _{I, sfo}Be that the sampling clock synchronization scenario is with reference to peak.

Frame synchronization peak value processing unit is according to the I of input _{I, peak}And lock signal output peak I _{I, fsyn}, I _{I, fsyn}Be that the frame synchronization scheme is with reference to peak.

Fig. 2 illustrates the structure chart of the peak value matching unit of Fig. 1.As shown in Figure 2, the peak matching unit comprises that peak displacement estimates module, some matching modules, matching detector.Wherein, peak displacement is estimated module, based on the I of preceding frame _{I, peak}Value output

Matching module is right And I _{I, peak}, I _{I, max1}, I _{I, max2}, I _{I, max3}... carry out matching judgment; Whether the matching detector module detects all matching modules genuine situation; The output locking signal.In one embodiment, before the output locking signal, add one and put the letter detection module, the output valve of each frame matching detector module is added up, when statistics satisfies a fixation creed part, just export locking signal, with the stability of enhanced system.

Concrete work and implementation procedure that peak displacement is estimated module are as follows:

A. at first be illustrated in conjunction with the channel impulse response function

Fig. 4 illustrates a kind of channel impulse response functional arrangement of the present invention.As shown in Figure 4, h (n) is the channel impulse response function.

Under ideal communication channel,

Because the channel magnitude function has only a peak value, its corresponding correlation peak also is unique, just can accurately estimate current peak based on the correlation peak location of preceding frame.Can judge relatively with the actual value in discreet value and the circuit whether this peak is believable.

Under the multipath situation, especially often there are two footpaths that energy is close in the 0db_echo situation of condition harshness owing in the channel, and the correlation peak of this footpath correspondence is close, this means I _{I, peak}Corresponding footpath is not unique.

Suppose to have in the channel two strong footpath h (0) that energy is close, h (1) (all the other footpaths all are 0), in a period of time, | h (0) |＞| h (1) |, I _{I, peak}Corresponding strong footpath is h (0) because channel becomes when being, sometime | h (0) |＜| h (1) |, this moment I _{I, peak}Corresponding strong footpath is h (1).Obviously the I that draws based on h (0) _{I, peak}Value can not judge whether this peak is believable.

I _{I, max1}, I _{I, max2}, I _{I, max3}... signal just can address this problem effectively, equally for as above situation, when | h (0) |＜| h (1) | the time, h (0) and h (1) corresponding peak value position are I _{I, max2}, I _{I, max1}, based on former frame I _{I, peak}Value can with I _{I, max2}Coupling, provable this peak is believable.

B. overall work process and realization

According to relevant criterion, can accurately estimate out current peak (the preceding frame of saying can refer to some frame that satisfies corresponding corresponding relation in former frames) here based on the correlation peak location of preceding frame.Preliminary election peak I based on preceding frame _{I, peak}, can obtain the preliminary election peak displacement of corresponding preceding frame; By this peak displacement amount, can obtain the peak displacement amount of present frame; The peak displacement amount of present frame is estimated the peak of estimating of present frame in conjunction with the preliminary election peak value of preceding frame; And carry out matching judgment by this discreet value and actual value.

In another embodiment, matching judgment is not directly calculated and is estimated peak, and is core with present frame peak displacement amount, and the preliminary election peak of frame and each peak of present frame carry out matching judgment before being aided with.In other embodiments, displacement also can satisfy in system and locks after putting the creed part, is generated automatically by system.

With continuous front cross frame is example, according to the peak displacement S of former frame _I-1=I _{I-1, peak}-I _{I-2, peak}Can draw the peak displacement S of this frame correspondence _i, preserve previous frame preliminary election peak I simultaneously _{I-1, peak}, basis again Value can obtain peak displacement and estimate module output

Under the ideal conditions, following relational expression is arranged:

{\tilde{I}}_{i, peak} = I_{i, peak} .

In actual channel, an I is always arranged, and (value of I is got I _{I, peak}, I _{I, max1}, I _{I, max2}, I _{I, max3}...) can satisfy following relational expression:

I = {\tilde{I}}_{i, peak} .

Under ideal communication channel, be example with the positive structure of China Digital TV ground standard (GB 20600-2006), present frame peak displacement S _iWith previous frame peak displacement S _I-1Concern as shown in the table:

C. be that example specifies the functional relation that its several embodiment realize with continuous front cross frame

With continuous front cross frame is example, further specifies in different embodiment peak displacement and estimates the specific implementation of module input and output relation and intermediate treatment and comprise following situation:

1. input is present frame preliminary election peak I _{I, peak}, output is present frame peak displacement S _iWith previous frame preliminary election peak I _{I-1, peak}

Preliminary election peak I according to the front cross frame of preserving _{I-1, peak}And I _{I-2, peak}As can be known:

S _i-1＝I _i-1，peak-I _i-2，peak；

For fixing frame structure, according to former frame peak displacement S _I-1Can obtain this frame peak displacement S _i

2. input is present frame preliminary election peak I _{I, peak}, output is the peak of estimating of the present frame estimated

S _i-1＝I _i-1，peak-I _i-2，peak。

By Can estimate out the peak of present frame

3. input is present frame preliminary election peak I _{I, peak}, output is the peak of estimating of the automatic present frame that generates

During lock=0, peak displacement is estimated module output and is realized and can draw according to 1 or 2.

During lock=1, this moment S _iValue can be directly by S _I-1Produce.S to 1 and 2 methods _iSubstitute.

More than the output variable of three kinds of implementations based on following several relations:

1) S _iWith S _I-1Relation is mainly determined by signal frame structure.

2)S _i＝I _i，peak-I _i-1，peak

3)

{\tilde{I}}_{i, peak} = S_{i} + I_{i - 1, peak}

Whether the matching detector module detects all matching modules genuine situation.

Putting the letter detection module adds up the output valve of each frame matching detector module, when the matching detector module detects matching module coupling is arranged, put that confidence counter then adds 1 in the letter detection module, otherwise subtract 1, when confidence counter provides locking signal during greater than threshold value.Be lock=1.

Fig. 3 illustrates the sampling clock sync peaks processing unit structure chart of Fig. 1.

Sampling clock sync peaks processing unit is according to the p of input _{I, peak}, I _{I, peak}, p _{I, idx}, idx and lock signal output peak I _{I, sfo}, I _{I, sfo}Be that the sampling clock synchronization scenario is with reference to peak;

Under constant channel, when the input lock=1 the time, I _{I, sfo}=I _{I, peak}

Sampling clock synchronized algorithm theoretical foundation is that the relevant output of lead and lag of strong footpath distributes and be similar to.I _{I, peak}Selection be the passing threshold method, along with channel constantly changes, I _{I, peak}Corresponding correlation decays to and will cause the sampling clock synchronized algorithm to lose efficacy when very little.I in addition _{I, peak}Frequent variations can cause the instability of system.

Based on analysis, the synchronous peak value of sampling clock does not need to represent most powerful path, if its intensity within certain tolerance, this peak still can be used as the synchronous peak value reference position of sampling clock.When intensity exceeds tolerance, substitute current peak with substituting peak.

As shown in Figure 3, sampling clock sync peaks processing unit comprises comparison selector 1, selector 2, peak output module 3 and comparator 4.

Relatively selector 1 is according to I _{I-1, sfo}With idx and p _{I, peak}, relatively select output I ' _{I, peak}Give selector 2 and export p ' _{I, peak}Give comparator 4.

Comparator 4 is according to p ' _{I, peak}And p _{I, peak}, carry out the judgement of threshold value, and give selector 2 result who judges.Specifically, comparator 4 is judged correlation p ' _{I, peak}Corresponding position I ' _{I, peak}Whether credible, i.e. p ' _{I, peak}/ p _{I, peak}Whether value is finished greater than threshold value.As p ' _{I, peak}/ p _{I, peak}Greater than threshold value explanation I ' _{I, peak}Be worth credible, selector 2 output I ' _{I, peak}Otherwise, then export I _{I, peak}

Selector 2 is according to the I ' of selector 1 output _{I, peak}Result and I with comparator 4 threshold decision _{I, peak}Select.If threshold decision is credible, output I ' _{I, peak}Otherwise, output I _{I, peak}

Peak output module 3 according to the output and the lock signal of selector 2, is exported I again _{I, sfo}In an example, peak output module 3 is a register, and only per frame period of this register only upgrades once, and this register output valve is I _{I, sfo}

Next, frame synchronization peak value processing unit is described.

Frame synchronization peak value processing unit mainly is the stable peak I of output _{I, fsyn}, in order to avoid I _{I, fsyn}Frequent variation causes the instability of system.

When lock==1, if I _{I-1, fsyn}==I _{I, peak}, then confidence counter adds 1, otherwise subtracts 1, when confidence counter during greater than certain value, and I _{I, fsyn}=I _{I-1, fsyn}, otherwise I _{I, fsyn}=I _{I, peak}

Embodiment under the PN595 pattern

With China Digital TV ground standard under the PN595 pattern (GB 20600-2006) receiver system is example, receives The data PN595, is illustrated this method and system.

1. set local sequence, it is relevant with local sequence to receive data, is input to the relevant treatment unit;

2. the relevant treatment unit is handled the present frame correlation,

Output p _{I, peak}, I _{I, peak}Give sampling clock sync peaks processing unit;

Output I _{I, peak}Give frame synchronization peak value processing unit;

Output I _{I, peak}, I _{I, max1}, I _{I, max2}Give the peak value matching unit;

3. check (I _{I, peak}==I _{I, max1}) || (I _{I, peak}==I _{I, max2}), if value is 1 then confidence counter adds 1, otherwise subtract 1, when confidence counter greater than 3 the time, lock==1;

4. in present frame, seek and satisfy | idx-I _{I-1, sfo}| the maximum related value p ' of≤1 idx correspondence _{I, peak}, judge p ' _{I, peak}/ p _{I, peak}Whether greater than 1/2, if sampling clock reference synchronization peak I _{I, sfo}=I ' _{I, peak}, otherwise output I _{I, sfo}=I _{I, peak}When lock==1, output I _{I, sfo}

5. if I _{I-1, fsyn}==I _{I, peak}, then confidence counter adds 1, otherwise subtracts 1, when confidence counter greater than 3 the time, I _{I, fsyn}=I _{I-1, fsyn}, otherwise I _{I, fsyn}=I _{I, peak}When lock==1, output I _{I, fsyn}

More than specific descriptions of the present invention are intended to illustrate the implementation of specific embodiments can not be interpreted as it is limitation of the present invention.Those of ordinary skills can make various variants on the basis of the embodiment that describes in detail under instruction of the present invention, these variants all should be included within the design of the present invention.The present invention's scope required for protection is only limited by described claims.

Claims

1. locking means during a correlation peak is handled may further comprise the steps:

It is relevant with local PN sequence to receive data;

Result to coupling carries out matching detection, to produce locking signal;

As not surpassing, continue the comparison of next peak value;

2. locking means according to claim 1 is characterized in that, and is further comprising the steps of before the generation of described locking signal:

3. locking means according to claim 1 and 2 is characterized in that, described matching detection adopt the matching result phase or mode.

4. locking means according to claim 1 and 2 is characterized in that, the peak displacement of described present frame is a true time in the locking signal of judging system, can be generated automatically by system according to the displacement relation between the frame of front and back under the fixing frame structure.

5. locking means according to claim 1 is characterized in that, described matching judgment judges according to the matching relationship expression formula whether each peak and input value satisfy this matching relationship expression formula.

6. locking system during a correlation peak is handled comprises: correlation unit, carry out receive data relevant with local PN sequence; The correlation processing unit is according to the preliminary election peak value and the preliminary election peak of correlated results calculating present frame; It is characterized in that described system also comprises the peak matching unit, comprising:

The matching detector module is carried out matching detection to matching result, the output locking signal;

Wherein, described correlation processing unit adopts following manner to calculate to the preliminary election peak value of present frame and the selection of preliminary election peak:

As not surpassing, continue the comparison of next peak value;

7. locking system according to claim 6 is characterized in that, described peak matching unit also comprises puts the letter detection module, wherein: according to mutually or after matching result, put the letter detection; Detect to satisfy when putting the letter threshold value when putting letter, export locking signal then.

8. according to claim 6 or 7 described locking systems, it is characterized in that described peak displacement is estimated module when obtaining the peak displacement of present frame, is true time in the locking signal of judging system, displacement can be generated by system automatically according to the displacement relation between the frame of front and back under the fixing frame structure.