CN102468866A - Timing synchronous method and device based on frequency domain difference mirror image correlation in LTE (long time evaluation) system - Google Patents

Abstract

The invention discloses a timing synchronous method and a device based on a frequency domain difference mirror image correlation in an LTE system. The method comprises the following steps of: firstly, receiving and storing a time domain receiving signal sequence which is sent by a base station and used for cell search and synchronization by a mobile user in the LTE system; secondly, performing FFT (fast Fourier transform) for the time domain receiving signal and obtaining a frequency domain receiving signal; thirdly, performing frequency domain difference mirror image correlation for the frequency domain receiving signal and obtaining a mirror image correlation result; fourthly, judging if an obvious peak value interval exists according to the absolute value of the mirror image correlation result, if yes, finding the position of the maximum relative peak according to the absolute value of the mirror image correlation result so as to finish the timing synchronization, otherwise, returning to the first step to detect continuously. The timing synchronous method and the device effectively eliminate the multi-path effect of the time domain, do not depend on a local synchronous sequence, make the synchronous signals sent by a plurality of cells in the synchronous network be available, and improve the accuracy of timing.

Description

The time synchronization method and the device of being correlated with based on the frequency domain differential demodulation mirror image in the LTE system

Technical field

The invention belongs to communication technical field, relate in a kind of LTE system based on frequency domain differential demodulation mirror image relevant time synchronization method and device.

Background technology

It is synchronous to carry out timing when the mobile subscriber inserts the sub-district, to confirm the reception sequential of signal.For making the user can effectively judge the reception signal sequence, cell base station periodically sends synchronizing signal, and synchronizing signal is integrated into the base station and user side is known.But the mobile subscriber does not know it specifically is which group in the synchronizing signal set as yet before inserting the sub-district; Therefore the mobile subscriber need seek effective method under the prerequisite of known synchronization signal set; Obtain the time sequence information of signal according to the burst that receives, accomplish timing synchronization procedure.

Zadoff-Chu (ZC) sequence is applied in a plurality of communication systems owing to possess good their cross correlation.In the LTE system, synchronizing signal is divided into two kinds of master sync signal and auxiliary synchronous signals.Wherein, master sync signal is generated by the ZC sequence, and each sub-district has three groups of master's synchronizing sequences optional, specifically sends which group in three groups of master's synchronizing sequences by network configuration.The LTE base station is every sends master sync signal one time at a distance from the 5ms cycle, and the user judges the 5ms periodic point of down receiving signal through the detection to master sync signal in the receiving sequence.

Traditional timing mode is: the user stores local Domain Synchronous sequence in advance, and slides relevantly with the time domain receiving sequence, maximal correlation peak value place is judged as the position of sending main synchronizing sequence, and then accomplishes regularly synchronously.In the LTE system, the user at first produces three groups of local time domain master synchronizing sequences, and every group of local time domain master synchronizing sequence slides relevantly with receiving signal respectively then, when detecting tangible peak value, confirms to detect the master sync signal position.The defective of this method is: (1) need not travel through each the group synchronizing sequence in the synchronizing sequence set owing to know synchronizing sequence call number, related operation as yet, so amount of calculation increases with synchronizing sequence group number in the synchronous set is linear; (2) in synchronous subzone network, the synchronizing signal that send a plurality of sub-districts becomes interference signal each other.

Summary of the invention

Technical problem to be solved by this invention is: provide in a kind of LTE system based on the relevant time synchronization method of frequency domain differential demodulation mirror image, this method does not rely on local synchronizing sequence, has improved accuracy regularly;

In addition, the present invention also provides in a kind of LTE system based on the relevant timing synchronization device of frequency domain differential demodulation mirror image.

For solving the problems of the technologies described above, the present invention adopts following technical scheme.

Based on the relevant time synchronization method of frequency domain differential demodulation mirror image, may further comprise the steps in a kind of LTE system:

Step 1, mobile subscriber in the LTE system receive and the storage base station be used for Cell searching and synchronous time domain receives burst;

Step 2 receives burst to said time domain and carries out the FFT conversion, obtains frequency domain and receives signal;

Step 3 is carried out the frequency domain differential demodulation mirror image to said frequency domain reception signal and is correlated with, and obtains the mirror image correlated results; The result that said frequency domain differential demodulation mirror image is relevant is:

$R\left(i\right)=\underset{l=\frac{N-L}{2}}{\overset{\frac{N}{2}-2}{\mathrm{\&Sigma;}}}{Y}_i^{*}(\frac{\mathrm{<figure-callout\; id="2"\; label="N"\; filenames="HDA0000032968010000012.png,HDA0000032968010000021.png"\; state="\{\{state\}\}">N</figure-callout>}}{2}+l+1)Y_i(\frac{\mathrm{<figure-callout\; id="2"\; label="N"\; filenames="HDA0000032968010000012.png,HDA0000032968010000021.png"\; state="\{\{state\}\}">N</figure-callout>}}{2}+l)Y_i^{*}(\frac{N}{2}-l)Y_i(\frac{N}{2}-l-1)$

Or

$R\left(i\right)=\underset{l=\frac{N-L}{2}}{\overset{\frac{N}{2}-2}{\mathrm{\&Sigma;}}}{Y}_i(\frac{\mathrm{<figure-callout\; id="2"\; label="N"\; filenames="HDA0000032968010000012.png,HDA0000032968010000021.png"\; state="\{\{state\}\}">N</figure-callout>}}{2}+l+1)Y_i^{*}(\frac{\mathrm{<figure-callout\; id="2"\; label="N"\; filenames="HDA0000032968010000012.png,HDA0000032968010000021.png"\; state="\{\{state\}\}">N</figure-callout>}}{2}+l)Y_i(\frac{N}{2}-l)Y_i^{*}(\frac{N}{2}-l-1),$

Wherein, Y _i(k) for being the FFT transformation results of the time domain reception burst of initial point with i, k is Y _i(k) sub-carrier indices, k=0,1,2 ..., N-1, N are the size of FFT conversion, and L is the length of the master sync signal in the LTE system, and according to protocol definition, L=62, l are the index number in the summation operation; Subscript * representes complex conjugate.

Step 4 judges whether to exist obvious peak value interval according to the absolute value of said mirror image correlated results, if exist, then finds the position of maximum correlation peak according to the absolute value of said mirror image correlated results, accomplishes regularly synchronously; Otherwise returning step 1 continues to detect.

As a kind of preferred version of the present invention, in the step 2, the acquisition process that said frequency domain receives signal is:

A) said Cell searching and the synchronous time domain of being used for received burst and be designated as y (i), i is the call number of sequence, i=0, and 1,2 ..., T-1, T are the sampling number of the reception burst in length detection time;

B) to being that the N point time domain of starting point receives burst y (0) with i=0, y (1) ..., y (N-1) carries out the FFT conversion, and obtaining frequency domain, to receive burst be Y ₀(0), Y ₀(1) ..., Y ₀(N-1);

C) to i=1,2 ... K-1 is that K continued time domain of initial point receives burst and carry out the FFT conversion, obtains frequency domain and receives signal and be:

$Y_i\left(k\right)=Y_{i-1}\left(k\right){\mathrm{<figure-callout\; id="2"\; label="e\; j"\; filenames="HDA0000032968010000012.png,HDA0000032968010000021.png"\; state="\{\{state\}\}">e</figure-callout>}}^j+y(i+N-1)e^{-\mathrm{<figure-callout\; id="2"\; label="j"\; filenames="HDA0000032968010000012.png,HDA0000032968010000021.png"\; state="\{\{state\}\}">j</figure-callout>}\frac{2\mathrm{\&pi;}(N-1)k}{N}}-y(i-1){\mathrm{<figure-callout\; id="2"\; label="e\; j"\; filenames="HDA0000032968010000012.png,HDA0000032968010000021.png"\; state="\{\{state\}\}">e</figure-callout>}}^j,$

Wherein, Y _i(k) being is the N point time domain reception burst y (i) of initial point with i, y (i+1) ..., the FFT transformation results of y (i+N-1), Y _I-1(k) being is the time domain reception burst y (i-1) of initial point with i-1, y (i) ..., the FFT transformation results of y (i+N-2), k=0,1 ..., N-1; K≤T-N.

As another kind of preferred version of the present invention, in the step 2, said frequency domain receives the obtain manner of signal and does the FFT conversion for directly said time domain being received burst.

Based on the relevant timing synchronization device of frequency domain differential demodulation mirror image, comprise memory module, FFT conversion module, frequency domain differential demodulation mirror image correlation module, synchronization module regularly in a kind of LTE system; Said memory module in order to the mobile subscriber in the storage LTE system receive be used for Cell searching and synchronous time domain receives burst; Said FFT conversion module links to each other with said memory module, is transformed to frequency domain reception signal in order to said time domain is received burst; Said frequency domain differential demodulation mirror image correlation module links to each other with said FFT conversion module, carries out difference mirror image relevant treatment in order to said frequency domain is received signal, obtains the mirror image correlated results; Said timing synchronization module links to each other with said difference mirror image correlation module, finds the position of maximum correlation peak to obtain timing information in order to the absolute value according to said mirror image correlated results, accomplishes synchronously.

As a kind of preferred version of the present invention, the model of said frequency domain differential demodulation mirror image correlation module is:

$R\left(i\right)=\underset{l=\frac{N-L}{2}}{\overset{\frac{N}{2}-2}{\mathrm{\&Sigma;}}}{Y}_i^{*}(\frac{\mathrm{<figure-callout\; id="2"\; label="N"\; filenames="HDA0000032968010000012.png,HDA0000032968010000021.png"\; state="\{\{state\}\}">N</figure-callout>}}{2}+l+1)Y_i(\frac{\mathrm{<figure-callout\; id="2"\; label="N"\; filenames="HDA0000032968010000012.png,HDA0000032968010000021.png"\; state="\{\{state\}\}">N</figure-callout>}}{2}+l)Y_i^{*}(\frac{N}{2}-l)Y_i(\frac{N}{2}-l-1)$

Or

$R\left(i\right)=\underset{l=\frac{N-L}{2}}{\overset{\frac{N}{2}-2}{\mathrm{\&Sigma;}}}{Y}_i(\frac{\mathrm{<figure-callout\; id="2"\; label="N"\; filenames="HDA0000032968010000012.png,HDA0000032968010000021.png"\; state="\{\{state\}\}">N</figure-callout>}}{2}+l+1)Y_i^{*}(\frac{\mathrm{<figure-callout\; id="2"\; label="N"\; filenames="HDA0000032968010000012.png,HDA0000032968010000021.png"\; state="\{\{state\}\}">N</figure-callout>}}{2}+l)Y_i(\frac{N}{2}-l)Y_i^{*}(\frac{N}{2}-l-1),$

Wherein, Y _i(k) for being the FFT transformation results of the time domain reception burst of initial point with i, k is Y _i(k) sub-carrier indices, k=0,1,2 ..., N-1, N are the size of FFT conversion, and L is the length of the master sync signal in the LTE system, and according to protocol definition, L=62, l are the index number in the summation operation; Subscript * representes complex conjugate.

As another kind of preferred version of the present invention, the model of said FFT conversion module is:

$Y_i\left(k\right)=Y_{i-1}\left(k\right){\mathrm{<figure-callout\; id="2"\; label="e\; j"\; filenames="HDA0000032968010000012.png,HDA0000032968010000021.png"\; state="\{\{state\}\}">e</figure-callout>}}^j+y(i+N-1)e^{-\mathrm{<figure-callout\; id="2"\; label="j"\; filenames="HDA0000032968010000012.png,HDA0000032968010000021.png"\; state="\{\{state\}\}">j</figure-callout>}\frac{2\mathrm{\&pi;}(N-1)k}{N}}-y(i-1){\mathrm{<figure-callout\; id="2"\; label="e\; j"\; filenames="HDA0000032968010000012.png,HDA0000032968010000021.png"\; state="\{\{state\}\}">e</figure-callout>}}^j,$

Y ₀(k)＝FFT(y(i))，i＝0，1，2，...，N-1

Wherein, Y _i(k) being is the time domain reception burst y (i) of initial point with i, y (i+1) ..., the FFT transformation results of y (i+N-1), Y _I-1(k) being is the time domain reception burst y (i-1) of initial point with i-1, y (i) ..., the FFT transformation results of y (i+N-2), Y ₀(k) being is the time domain reception burst y (0) of initial point with i=0, y (1) ..., the FFT transformation results of y (N-1), k=0,1 ..., N-1, N are the size of FFT conversion.

Beneficial effect of the present invention is: the present invention is synchronous through the timing of user in the frequency domain differential demodulation mirror image related realization LTE system and base station, has effectively eliminated the time domain multipath effect; And; The present invention does not rely on local synchronizing sequence, and the signal of participating in related operation directly comes from the reception signal, and the synchronizing signal that therefore send a plurality of sub-districts in synchronizing network all is a useful signal; Thereby make that the maximal correlation peak value is more obvious, improved accuracy regularly.

Description of drawings

Fig. 1 is based on the relevant time synchronization method flow chart of frequency domain differential demodulation mirror image in the LTE of the present invention system;

Fig. 2 is the PSS sequence subcarrier in frequency domain mapping mode sketch map among the embodiment two;

Fig. 3 is among the embodiment two being that 64 time domains of starting point receive the burst sketch mapes with i;

Fig. 4 is among the embodiment two being that 64 frequency domains of starting point receive signal schematic representations with i;

Fig. 5 is based on the structural representation of the relevant timing synchronization device of frequency domain differential demodulation mirror image in the LTE of the present invention system.

Embodiment

The present invention propose a kind of LTE of being applicable to system utilize frequency domain to receive signal to accomplish regularly synchronous method and apparatus.This method at first will receive signal transformation to frequency domain, and it is relevant then frequency-region signal to be carried out difference mirror image symmetry, accomplish regularly synchronously after detecting obvious peak value.

Do further explain below in conjunction with the accompanying drawing specific embodiments of the invention.

Embodiment one

Present embodiment provides in a kind of LTE system based on the relevant time synchronization method of frequency domain differential demodulation mirror image, and the flow process of this method is as shown in Figure 1, specifically comprises:

(1) the storage time domain receives burst.

To be used for Cell searching and synchronous time domain and receive burst and be designated as y (i), i is the call number of sequence, i=0, and 1,2 ..., T-1, T are the sampling number of the reception burst in length detection time.

(2) obtain frequency domain and receive burst.

Time domain is received burst y (i) carry out the FFT conversion, obtain frequency domain and receive signal; Record is that the FFT that K continued time domain that starting point begins receives signal is transformed to Y with i _i(k), wherein, k is that frequency domain receives signal Y _i(k) sub-carrier indices, k=0,1,2 ..., N-1, N are the size of FFT conversion.

Frequency domain receives signal Y _i(k) be to adopt based on Y _I-1(k) obtain Y _i(k) slip iterative computation mode obtains, and the detailed calculated mode is following:

A) with i=0 be the N point time domain reception burst y (0) of starting point, y (1) ..., the FFT of y (N-1) is transformed to Y ₀(0), Y ₀(1) ..., Y ₀(N-1);

B) with i=1,2 .... the FFT that receives burst for the N point time domain of initial point is transformed to:

$Y_i\left(k\right)=Y_{i-1}\left(k\right){\mathrm{<figure-callout\; id="2"\; label="e\; j"\; filenames="HDA0000032968010000012.png,HDA0000032968010000021.png"\; state="\{\{state\}\}">e</figure-callout>}}^j+y(i+N-1)e^{-\mathrm{<figure-callout\; id="2"\; label="j"\; filenames="HDA0000032968010000012.png,HDA0000032968010000021.png"\; state="\{\{state\}\}">j</figure-callout>}\frac{2\mathrm{\&pi;}(N-1)k}{N}}-y(i-1){\mathrm{<figure-callout\; id="2"\; label="e\; j"\; filenames="HDA0000032968010000012.png,HDA0000032968010000021.png"\; state="\{\{state\}\}">e</figure-callout>}}^j,$ k＝0，1，...，N-1

(3) the frequency domain differential demodulation mirror image is relevant.

Frequency domain is received signal Y _i(k) carry out the frequency domain differential demodulation mirror image and be correlated with, acquisition mirror image correlated results is:

$R\left(i\right)=\underset{l=\frac{N-L}{2}}{\overset{\frac{N}{2}-2}{\mathrm{\&Sigma;}}}{Y}_i^{*}(\frac{\mathrm{<figure-callout\; id="2"\; label="N"\; filenames="HDA0000032968010000012.png,HDA0000032968010000021.png"\; state="\{\{state\}\}">N</figure-callout>}}{2}+l+1)Y_i(\frac{\mathrm{<figure-callout\; id="2"\; label="N"\; filenames="HDA0000032968010000012.png,HDA0000032968010000021.png"\; state="\{\{state\}\}">N</figure-callout>}}{2}+l)Y_i^{*}(\frac{N}{2}-l)Y_i(\frac{N}{2}-l-1)$

Or

$R\left(i\right)=\underset{l=\frac{N-L}{2}}{\overset{\frac{N}{2}-2}{\mathrm{\&Sigma;}}}{Y}_i(\frac{\mathrm{<figure-callout\; id="2"\; label="N"\; filenames="HDA0000032968010000012.png,HDA0000032968010000021.png"\; state="\{\{state\}\}">N</figure-callout>}}{2}+l+1)Y_i^{*}(\frac{\mathrm{<figure-callout\; id="2"\; label="N"\; filenames="HDA0000032968010000012.png,HDA0000032968010000021.png"\; state="\{\{state\}\}">N</figure-callout>}}{2}+l)Y_i(\frac{N}{2}-l)Y_i^{*}(\frac{N}{2}-l-1),$

Wherein, L=62 is the ZC sequence length of actual use, i.e. the physical length of master sync signal in the LET system.

(4) regularly synchronously.

Absolute value according to mirror image correlated results R (i) judges whether to exist obvious peak value interval, if exist, then finds the position of maximum correlation peak according to the absolute value of R (i), accomplishes regularly synchronously; Otherwise continue to detect.

The present invention need not carry out related operation respectively to many groups of local synchronizing sequences; And frequency domain reception signal is carried out difference mirror image related operation can obtain the gain of time domain rake; In addition, because the signal of participating in related operation is from receiving signal, therefore in synchronizing network, the synchronizing signal that send a plurality of sub-districts all is a useful signal, thereby makes that the maximal correlation peak value is more obvious, has improved accuracy regularly.

Embodiment two

Present embodiment provides the concrete implementation procedure of embodiment one a said method.Wherein, the big or small N=64 of FFT conversion, the sub-carrier indices k=0 of frequency-region signal, 1 ..., 63.Master sync signal (record master sync signal sequence is PSS (n) for primary synchronoussignal, length L PSS)=62, n=0, and 1 ..., 61, corresponding master sync signal is as shown in Figure 2 at the mapping mode of subcarrier in frequency domain.Wherein, k=0 is the direct current subcarrier, and k=32 is the gap carrier wave.It is the frequency domain reception signal after 64 time domains of starting point receive burst and FFT conversion that Fig. 3 and Fig. 4 provide respectively with i.

Suppose that it is y (i) that the user begins to receive the time domain reception burst of storing after the data that is used for Cell searching, i=0,1 ... ..4800-1, i.e. T=4800; Be equivalent to receiver and stored the data of half radio frames in the 5ms.The frequency domain timing process is following:

1) calculating with i=0 is 64 time-domain signal y (0) of starting point, y (1) ..., the FFT conversion of y (63) obtains 64 frequency-region signal sequence Y ₀(0), Y ₀(1) ..., Y ₀(63);

Frequency domain differential demodulation mirror image when 2) calculating i=0 is relevant:

$R\left(0\right)=\underset{l=1}{\overset{30}{\mathrm{\&Sigma;}}}{{\mathrm{<figure-callout\; id="0"\; label="Y"\; filenames="HDA0000032968010000012.png"\; state="\{\{state\}\}">Y</figure-callout>}}_0}^{*}(32+l+1)Y_0(32+l){{\mathrm{<figure-callout\; id="0"\; label="Y"\; filenames="HDA0000032968010000012.png"\; state="\{\{state\}\}">Y</figure-callout>}}_0}^{*}(32-l)Y_0(32-l-1);$

3) calculating with i=1 is 64 time-domain signal y (1) of starting point, y (2) ..., the FFT conversion of y (64) obtains 64 frequency-region signal sequence Y ₁(0), Y ₁(1) ..., Y ₁(63), account form is following:

$Y_1\left(k\right)=Y_0\left(k\right){\mathrm{<figure-callout\; id="2"\; label="e\; j"\; filenames="HDA0000032968010000012.png,HDA0000032968010000021.png"\; state="\{\{state\}\}">e</figure-callout>}}^j+y\left(64\right)e^{-\mathrm{<figure-callout\; id="2"\; label="j"\; filenames="HDA0000032968010000012.png,HDA0000032968010000021.png"\; state="\{\{state\}\}">j</figure-callout>}\frac{2\mathrm{\&pi;}\&CenterDot;63\&CenterDot;k}{64}}-y\left(0\right){\mathrm{<figure-callout\; id="2"\; label="e\; j"\; filenames="HDA0000032968010000012.png,HDA0000032968010000021.png"\; state="\{\{state\}\}">e</figure-callout>}}^j,$ k＝0，1，...，N-1；

Frequency domain differential demodulation mirror image when 4) calculating i=1 is relevant:

$R\left(1\right)=\underset{l=1}{\overset{30}{\mathrm{\&Sigma;}}}{\mathrm{<figure-callout\; id="1"\; label="Y"\; filenames="HDA0000032968010000012.png,HDA0000032968010000021.png"\; state="\{\{state\}\}">Y</figure-callout>}}_1^{*}(32+l+1)Y_1(32+l){\mathrm{<figure-callout\; id="1"\; label="Y"\; filenames="HDA0000032968010000012.png,HDA0000032968010000021.png"\; state="\{\{state\}\}">Y</figure-callout>}}_1^{*}(32-l)Y_1(32-l-1);$

5) slide successively that to get length be 64 time-domain signal, according to step 3) and 4) account form obtain i=2 respectively, 3 ... the time correlation:

$Y_i\left(k\right)=Y_{i-1}\left(k\right){\mathrm{<figure-callout\; id="2"\; label="e\; j"\; filenames="HDA0000032968010000012.png,HDA0000032968010000021.png"\; state="\{\{state\}\}">e</figure-callout>}}^j+y(i+63)e^{-\mathrm{<figure-callout\; id="2"\; label="j"\; filenames="HDA0000032968010000012.png,HDA0000032968010000021.png"\; state="\{\{state\}\}">j</figure-callout>}\frac{2\mathrm{\&pi;}\&CenterDot;63\&CenterDot;k}{64}}-y(i-1){\mathrm{<figure-callout\; id="2"\; label="e\; j"\; filenames="HDA0000032968010000012.png,HDA0000032968010000021.png"\; state="\{\{state\}\}">e</figure-callout>}}^j,$

$R\left(i\right)=\underset{l=1}{\overset{30}{\mathrm{\&Sigma;}}}{Y}_i^{*}(32+l+1)Y_i(32+l)Y_i^{*}(32-l)Y_i(32-l-1);$

6) according to R (i) (i=0,1 ... absolute value ..4800-1-63) judges whether to exist obvious peak value interval, if there is the position of then finding maximum correlation peak according to the absolute value of R (i), accomplishes regularly synchronously; Otherwise continuation storage data or replacing frequency range detect.

Embodiment three

Present embodiment provides a kind of device of the embodiment of realization one said time synchronization method, and is as shown in Figure 5, and this device comprises memory module, FFT conversion module, frequency domain differential demodulation mirror image correlation module, regularly synchronization module.

[memory module]

Memory module in order to the mobile subscriber in the storage LTE system receive be used for Cell searching and synchronous time domain receives burst;

[FFT conversion module]

The FFT conversion module links to each other with said memory module, is transformed to frequency domain reception signal in order to said time domain is received burst; The model of FFT conversion module is:

$Y_i\left(k\right)=Y_{i-1}\left(k\right){\mathrm{<figure-callout\; id="2"\; label="e\; j"\; filenames="HDA0000032968010000012.png,HDA0000032968010000021.png"\; state="\{\{state\}\}">e</figure-callout>}}^j+y(i+N-1)e^{-\mathrm{<figure-callout\; id="2"\; label="j"\; filenames="HDA0000032968010000012.png,HDA0000032968010000021.png"\; state="\{\{state\}\}">j</figure-callout>}\frac{2\mathrm{\&pi;}(N-1)k}{N}}-y(i-1){\mathrm{<figure-callout\; id="2"\; label="e\; j"\; filenames="HDA0000032968010000012.png,HDA0000032968010000021.png"\; state="\{\{state\}\}">e</figure-callout>}}^j,$

Y ₀(k)＝FFT(y(i))，i＝0，1，2，...，N-1

Wherein, Y _i(k) being is the time domain reception burst y (i) of initial point with i, y (i+1) ..., the FFT transformation results of y (i+N-1), Y _I-1(k) being is the time domain reception burst y (i-1) of initial point with i-1, y (i) ..., the FFT transformation results of y (i+N-2), Y ₀(k) being is the time domain reception burst y (0) of initial point with i=0, y (1) ..., the FFT transformation results of y (N-1), k=0,1 ..., N-1, N are the size of FFT conversion.

[frequency domain differential demodulation mirror image correlation module]

Frequency domain differential demodulation mirror image correlation module links to each other with said FFT conversion module, carries out difference mirror image relevant treatment in order to said frequency domain is received signal, obtains the mirror image correlated results; The model of frequency domain differential demodulation mirror image correlation module is:

$R\left(i\right)=\underset{l=\frac{N-L}{2}}{\overset{\frac{N}{2}-2}{\mathrm{\&Sigma;}}}{Y}_i^{*}(\frac{\mathrm{<figure-callout\; id="2"\; label="N"\; filenames="HDA0000032968010000012.png,HDA0000032968010000021.png"\; state="\{\{state\}\}">N</figure-callout>}}{2}+l+1)Y_i(\frac{\mathrm{<figure-callout\; id="2"\; label="N"\; filenames="HDA0000032968010000012.png,HDA0000032968010000021.png"\; state="\{\{state\}\}">N</figure-callout>}}{2}+l)Y_i^{*}(\frac{N}{2}-l)Y_i(\frac{N}{2}-l-1)$

Or

$R\left(i\right)=\underset{l=\frac{N-L}{2}}{\overset{\frac{N}{2}-2}{\mathrm{\&Sigma;}}}{Y}_i(\frac{\mathrm{<figure-callout\; id="2"\; label="N"\; filenames="HDA0000032968010000012.png,HDA0000032968010000021.png"\; state="\{\{state\}\}">N</figure-callout>}}{2}+l+1)Y_i^{*}(\frac{\mathrm{<figure-callout\; id="2"\; label="N"\; filenames="HDA0000032968010000012.png,HDA0000032968010000021.png"\; state="\{\{state\}\}">N</figure-callout>}}{2}+l)Y_i(\frac{N}{2}-l)Y_i^{*}(\frac{N}{2}-l-1),$

Wherein, Y _i(k) for being the FFT transformation results of the time domain reception burst of initial point with i, k is Y _i(k) sub-carrier indices, k=0,1,2 ..., N-1, N are the size of FFT conversion, and L is the length of the master sync signal in the LTE system, and according to protocol definition, L=62, l are the index number in the summation operation; Subscript * representes complex conjugate.

[regularly synchronization module]

Regularly synchronization module links to each other with said difference mirror image correlation module, finds the position of maximum correlation peak to obtain timing information in order to the absolute value according to said mirror image correlated results, accomplishes synchronously.

Here description of the invention and application is illustrative, is not to want with scope restriction of the present invention in the above-described embodiments.Here the distortion of the embodiment that is disclosed and change are possible, and the replacement of embodiment is known with the various parts of equivalence for those those of ordinary skill in the art.Those skilled in the art are noted that under the situation that does not break away from spirit of the present invention or substantive characteristics, and the present invention can be with other forms, structure, layout, ratio, and realize with other elements, material and parts.

Claims (7)

1. In the LTE system based on the relevant time synchronization method of frequency domain differential demodulation mirror image, it is characterized in that said time synchronization method may further comprise the steps:

   Step 1, mobile subscriber in the LTE system receive and the storage base station be used for Cell searching and synchronous time domain receives burst;

   Step 2 receives burst to said time domain and carries out the FFT conversion, obtains frequency domain and receives signal;

   Step 3 is carried out the frequency domain differential demodulation mirror image to said frequency domain reception signal and is correlated with, and obtains the mirror image correlated results;

   Step 4 judges whether to exist obvious peak value interval according to the absolute value of said mirror image correlated results, if exist, then finds the position of maximum correlation peak according to the absolute value of said mirror image correlated results, accomplishes regularly synchronously; Otherwise returning step 1 continues to detect.
2. 2. based on the relevant time synchronization method of frequency domain differential demodulation mirror image, it is characterized in that in the LTE according to claim 1 system: in the step 3, the result that said frequency domain differential demodulation mirror image is relevant is:

   $R\left(i\right)=\underset{l=\frac{N-L}{2}}{\overset{\frac{N}{2}-2}{\mathrm{\&Sigma;}}}{Y}_i^{*}(\frac{N}{2}+l+1)Y_i(\frac{N}{2}+l)Y_i^{*}(\frac{N}{2}-l)Y_i(\frac{N}{2}-l-1)$

   Or

   $R\left(i\right)=\underset{l=\frac{N-L}{2}}{\overset{\frac{N}{2}-2}{\mathrm{\&Sigma;}}}{Y}_i(\frac{N}{2}+l+1)Y_i^{*}(\frac{N}{2}+l)Y_i(\frac{N}{2}-l)Y_i^{*}(\frac{N}{2}-l-1),$

   Wherein, Y _i(k) for i being the FFT transformation results of the time domain reception burst of initial point, Y _i(k) for frequency domain receives signal, k is Y _i(k) sub-carrier indices, k=0,1,2 ..., N-1, N are the size of FFT conversion, and L is the length of the master sync signal in the LTE system, and L=62, l are the index number in the summation operation; Subscript * representes complex conjugate.
3. 3. based on the relevant time synchronization method of frequency domain differential demodulation mirror image, it is characterized in that in the LTE according to claim 2 system: in the step 2, the acquisition process that said frequency domain receives signal is:

   A) said Cell searching and the synchronous time domain of being used for received burst and be designated as y (i), i is the call number of sequence, i=0, and 1,2 ..., T-1, T are the sampling number of the reception burst in length detection time;

   B) to being that the N point time domain of starting point receives burst y (0) with i=0, y (1) ..., y (N-1) carries out the FFT conversion, and obtaining frequency domain, to receive burst be Y ₀(0), Y ₀(1) ..., Y ₀(N-1);

   C) to i=1,2 ... K-1 is that K continued time domain of initial point receives burst and carry out the FFT conversion, obtains frequency domain and receives signal and be:

   $Y_i\left(k\right)=Y_{i-1}\left(k\right)e^{j\frac{2\mathrm{\&pi;k}}{N}}+y(i+N-1)e^{-j\frac{2\mathrm{\&pi;}(N-1)k}{N}}-y(i-1)e^{j\frac{2\mathrm{\&pi;k}}{N}},$

   Wherein, Y _i(k) being is the N point time domain reception burst y (i) of initial point with i, y (i+1) ..., the FFT transformation results of y (i+N-1), Y _I-1(k) being is the time domain reception burst y (i-1) of initial point with i-1, y (i) ..., the FFT transformation results of y (i+N-2), k=0,1 ..., N-1; K≤T-N.
4. 4. based on the relevant time synchronization method of frequency domain differential demodulation mirror image, it is characterized in that in the LTE according to claim 2 system: in the step 2, said frequency domain receives the obtain manner of signal for directly said time domain reception burst being done the FFT conversion.
5. In the LTE system based on the relevant timing synchronization device of frequency domain differential demodulation mirror image, it is characterized in that: said timing synchronization device comprises memory module, FFT conversion module, frequency domain differential demodulation mirror image correlation module, synchronization module regularly; Said memory module in order to the mobile subscriber in the storage LTE system receive be used for Cell searching and synchronous time domain receives burst; Said FFT conversion module links to each other with said memory module, is transformed to frequency domain reception signal in order to said time domain is received burst; Said frequency domain differential demodulation mirror image correlation module links to each other with said FFT conversion module, carries out difference mirror image relevant treatment in order to said frequency domain is received signal, obtains the mirror image correlated results; Said timing synchronization module links to each other with said difference mirror image correlation module, finds the position of maximum correlation peak to obtain timing information in order to the absolute value according to said mirror image correlated results, accomplishes synchronously.
6. 6. based on the relevant timing synchronization device of frequency domain differential demodulation mirror image, it is characterized in that: the model of said frequency domain differential demodulation mirror image correlation module is in the LTE according to claim 5 system:

   $R\left(i\right)=\underset{l=\frac{N-L}{2}}{\overset{\frac{N}{2}-2}{\mathrm{\&Sigma;}}}{Y}_i^{*}(\frac{N}{2}+l+1)Y_i(\frac{N}{2}+l)Y_i^{*}(\frac{N}{2}-l)Y_i(\frac{N}{2}-l-1)$

   Or

   $R\left(i\right)=\underset{l=\frac{N-L}{2}}{\overset{\frac{N}{2}-2}{\mathrm{\&Sigma;}}}{Y}_i(\frac{N}{2}+l+1)Y_i^{*}(\frac{N}{2}+l)Y_i(\frac{N}{2}-l)Y_i^{*}(\frac{N}{2}-l-1),$

   Wherein, Y _i(k) for being the FFT transformation results of the time domain reception burst of initial point with i, k is Y _i(k) sub-carrier indices, k=0,1,2 ..., N-1, N are the size of FFT conversion, and L is the length of the master sync signal in the LTE system, and L=62, l are the index number in the summation operation; Subscript * representes complex conjugate.
7. 7. based on the relevant timing synchronization device of frequency domain differential demodulation mirror image, it is characterized in that: the model of said FFT conversion module is in the LTE according to claim 5 system:

   $Y_i\left(k\right)=Y_{i-1}\left(k\right)e^{j\frac{2\mathrm{\&pi;k}}{N}}+y(i+N-1)e^{-j\frac{2\mathrm{\&pi;}(N-1)k}{N}}-y(i-1)e^{j\frac{2\mathrm{\&pi;k}}{N}},$

   Y ₀(k)＝FFT(y(i))，i＝0，1，2，...，N-1，

   Wherein, Y _i(k) being is the time domain reception burst y (i) of initial point with i, y (i+1) ..., the FFT transformation results of y (i+N-1), Y _I-1(k) being is the time domain reception burst y (i-1) of initial point with i-1, y (i) ..., the FFT transformation results of y (i+N-2), Y ₀(k) being is the time domain reception burst y (0) of initial point with i=0, y (1) ..., the FFT transformation results of y (N-1), k=0,1 ..., N-1, N are the size of FFT conversion.

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