CN102857457A - Time division duplexing-long term evolution (TDD-LTE) downlink synchronizing method - Google Patents

Abstract

The invention is applicable to the field of Time division duplexing-long term evolution (TDD-LTE) system communication and provides a TDD-LTE downlink synchronizing method. The method includes obtaining half-frame synchronization information and serial numbers in a cell identity (ID) group; determining a cyclic prefix (CP) type; subjecting a frequency domain secondary synchronization sequence to de-interleaving and descrambling to obtain an even sequence and an odd sequence respectively; subjecting the even sequence and a secondary original sequence to circular correlation and recording a coordinate corresponding to a peak value of correlation values as a first displacement coordinate; generating a third descrambling sequence according to the first displacement coordinate; descrambling the odd sequence and the third descrambling sequence, subjecting the odd sequence, the third descrambling sequence and the secondary original sequence to circular correlation, and recording a coordinate corresponding to a peak value of correlation values as a second displacement coordinate; and obtaining a cell ID group serial number and frame starting information according to the first displacement coordinate and the second displacement coordinate. According to the TDD-LTE downlink synchronizing method, m<0> and m<1> can be determined only by performing 31 times of cross-correlation calculation with the length of 31, so that TDD-LTE downlink synchronization information is obtained, and the calculation amount is greatly reduced.

Description

A kind of TDD-LTE down link synchronisation method

Technical field

The invention belongs to long evolving system (Time Division Duplexing-Long Term Evolution, the TDD-LTE) communications field of TDD mode, relate in particular to a kind of TDD-LTE down link synchronisation method.

Background technology

The physical layer of LTE system has adopted OFDM (Orthogonal Frequency Division Multiplexing, OFDM) modulation technique, wherein, the OFDM symbol is made of a plurality of sub-carrier signal stacks, and utilize orthogonality to distinguish between each subcarrier, thereby the TDD-LTE system is very responsive to the frequency shift (FS) of signal.But in actual applications, because the radio frequency oscillator frequency deviation that transmitting-receiving two-end exists, and travelling carriage is in the Doppler Doppler frequency displacement that produces in the high-speed mobile environment, all can destroy the orthogonality between the subcarrier, and then the introducing subcarrier interference, cause the systematic function decrease.Therefore, in the LTE system, how to obtain synchronously, namely the LTE terminal how to obtain and the residential quarter between time and Frequency Synchronization and detect physical-layer cell ID, be at first to need the problem that solves.

In the TDD-LTE system, the subframe (subframe) that it is 1ms that the radio frames of a 10ms (radio frame) is divided into 10 length, and take subframe as unit the up-downgoing resource is configured.In order to realize the down-going synchronous of TDD-LTE system, when system, on down channel, transmit respectively master sync signal (PSCH) and auxiliary synchronous signals (SSCH), wherein, master sync signal is mapped on the 3rd the OFDM symbol of the 1st work song frame and the 6th work song frame, and auxiliary synchronous signals is mapped on last OFDM symbol of the 0th work song frame and the 5th work song frame.The realization flow of down-going synchronous is roughly: the TDD-LTE terminal is according to the correlation detection master sync signal of master sync signal, obtain the 5ms clock, be field sync information, according to the correlation detection auxiliary synchronous signals of auxiliary synchronous signals, obtain frame synchronization information and physical-layer cell ID again.In existing auxiliary synchronizing process, according to the good autocorrelation of secondary synchronization sequences on frequency domain, by itself and the method that the reception signal is done cross-correlation at frequency domain are obtained auxiliary synchronizing information, yet, it is 62 computing cross-correlation that said process need to be done length with receiving sequence respectively with 168 groups of secondary synchronization sequences, amount of calculation is huge, causes the system resource burden large.

Summary of the invention

The purpose of the embodiment of the invention is to provide a kind of TDD-LTE down link synchronisation method, and the auxiliary synchronizing process amount of calculation that is intended to solve existing TDD-LTE down link synchronisation method is huge, causes the large problem of system burden.

The embodiment of the invention is achieved in that a kind of TDD-LTE down link synchronisation method, and described method comprises the steps:

With master sync signal and reception Signal cross correlation, obtain the interior numbering of group of field sync information and residential quarter ID;

With cyclic prefix CP data and master sync signal end CP length data cross-correlation, determine the CP type;

Generate local scrambling sequence and auxiliary synchronous original series, described local scrambling sequence comprises the first scrambling sequence and the second scrambling sequence;

According to master sync signal initial time and CP type, extract the time domain secondary synchronization sequences, and be converted to the frequency domain secondary synchronization sequences;

With the deinterleaving of described frequency domain secondary synchronization sequences and respectively with described the first scrambling sequence and described the second scrambling sequence descrambling after, obtain respectively even number sequence and odd number sequence;

With described even number sequence and described auxiliary synchronous original series circular correlation, the coordinate record that correlation peaks is corresponding is the first displacement coordinate;

According to described the first displacement coordinate, generate the 3rd scrambling sequence;

Behind described odd number sequence and described the 3rd scrambling sequence descrambling, with described auxiliary synchronous original series circular correlation, the coordinate record that correlation peaks is corresponding is the second displacement coordinate;

According to described the first displacement coordinate and described the second displacement coordinate, obtain residential quarter ID group #, and according to the relative position of described the first displacement coordinate with described the second displacement coordinate, calculating frame start information.

Another purpose of the embodiment of the invention is to provide a kind of TDD-LTE downlink synchronization device, and described device comprises:

Main lock unit is used for master sync signal and reception Signal cross correlation, obtains the interior numbering of group of field sync information and residential quarter ID;

CP type determining unit is used for cyclic prefix CP data and master sync signal end CP length data cross-correlation, determines the CP type;

Local scrambling sequence and auxiliary synchronous original series generation unit are used for generating local scrambling sequence and auxiliary synchronous original series, and described local scrambling sequence comprises the first scrambling sequence and the second scrambling sequence;

Frequency domain secondary synchronization sequences acquiring unit is used for according to master sync signal initial time and CP type, extracts the time domain secondary synchronization sequences, and is converted to the frequency domain secondary synchronization sequences;

The sequence of parity acquiring unit, be used for the deinterleaving of described frequency domain secondary synchronization sequences and respectively with described the first scrambling sequence and described the second scrambling sequence descrambling after, obtain respectively even number sequence and odd number sequence;

The first displacement coordinate acquiring unit is used for described even number sequence and described auxiliary synchronous original series circular correlation, and the coordinate record that correlation peaks is corresponding is the first displacement coordinate;

The 3rd scrambling sequence generation unit is used for generating the 3rd scrambling sequence according to described the first displacement coordinate;

The second displacement coordinate acquiring unit is used for behind described odd number sequence and described the 3rd scrambling sequence descrambling, and with described auxiliary synchronous original series circular correlation, the coordinate record that correlation peaks is corresponding is the second displacement coordinate;

Residential quarter ID group # and frame start information acquiring unit, be used for according to described the first displacement coordinate and described the second displacement coordinate, obtain residential quarter ID group #, and according to the relative position of described the first displacement coordinate with described the second displacement coordinate, calculating frame start information.

The embodiment of the invention is in the synchronous auxiliary synchronizing process of TDD-LTE system descending, after will receiving signal deinterleaving and descrambling, obtain corresponding even number sequence and odd number sequence, correspondingly finish auxiliary synchronous signals and the cross-correlation procedure that receives signal, reduce widely thus the amount of calculation of auxiliary synchronizing process, alleviated system burden.

Description of drawings

Fig. 1 is the realization flow figure of the TDD-LTE down link synchronisation method that provides of first embodiment of the invention;

Fig. 2 is the structure chart of the TDD-LTE downlink synchronization device that provides of second embodiment of the invention.

Embodiment

In order to make purpose of the present invention, technical scheme and advantage clearer, below in conjunction with drawings and Examples, the present invention is further elaborated.Should be appreciated that specific embodiment described herein only in order to explain the present invention, is not intended to limit the present invention.

The embodiment of the invention is in the synchronous auxiliary synchronizing process of TDD-LTE system descending, after will receiving signal deinterleaving and descrambling, obtain corresponding even number sequence and odd number sequence, correspondingly finish auxiliary synchronous signals and the cross-correlation procedure that receives signal, reduce widely thus the amount of calculation of auxiliary synchronizing process, alleviated system burden.

The down-going synchronous process of TDD-LTE system namely is that subscriber equipment (User Equipment, UE) is obtained time and Frequency Synchronization with residential quarter of living in, and detects the process of the residential quarter ID of this residential quarter.In the physical layer of TDD-LTE system, exist 504 unique residential quarter ID, these residential quarters ID is divided into 168 unique residential quarter ID groups, and each group comprises 3 unique residential quarter ID, therefore, a residential quarter ID

Wherein, (scope is 0-167) and

(scope is 0-2) represents respectively in the residing residential quarter of ID, this residential quarter ID group # and its group in this residential quarter ID group and numbers, when getting cicada

Know

Can determine a residential quarter ID.

Simultaneously, because master sync signal is mapped on the 3rd the OFDM symbol of the 1st work song frame of TDD-LTE radio frames and the 6th work song frame, therefore can obtain 5ms field sync information by main synchronizing process; Auxiliary synchronous signals is mapped on last OFDM symbol of the 0th work song frame of TDD-LTE radio frames and the 5th work song frame, and it is different with the secondary synchronization sequences of the 5th work song frame to be mapped to the 0th work song frame, therefore can get access to the border of 10ms by auxiliary synchronizing process, namely get access to the 10ms frame synchronization information.

Fig. 1 shows the realization flow of the TDD-LTE down link synchronisation method that first embodiment of the invention provides, and details are as follows:

In step S101, by with master sync signal and reception Signal cross correlation, obtain the interior numbering of group of field sync information and residential quarter ID

Because master sync signal all has good autocorrelation on time domain and frequency domain, therefore, master sync signal and reception signal are carried out cross-correlation, and then search correlation peaks, obtain thus the positional information of master sync signal in receiving signal, and further obtain numbering in field sync information and the residential quarter ID group.

The idiographic flow of main synchronizing process is as follows:

1, is the main synchronizing sequence that 62 frequency domain Zadoff-Chu sequence generates frequency domain according to length, and maps on 62 frequencies at subcarrier center.Wherein, the Zadoff-Chu sequence is:

$d_u\left(n\right)=\left\{\begin{array}{cc}{e}^{-j\frac{\mathrm{\&pi;un}(n+1)}{63}}& n=\mathrm{0,1},...,30\\ e^{-j\frac{\mathrm{\&pi;u}(n+1)(n+2)}{63}}& n=\mathrm{31,32},...,61\end{array}\right.,$

And the index u of Zadoff-Chu root sequence is given by table 1:

Table 1

2, insert the direct current subcarrier at the subcarrier center; on 5 subcarriers before and after the main synchronizing sequence, insert respectively 5 protection subcarriers; then with main synchronizing sequence zero padding to the FFT under the minimum bandwidth count (128 point); around revolving; do the IFFT conversion, the main synchronizing sequence of frequency domain is converted to the main synchronizing sequence of time domain.

3, will receive signal down-sampled to appropriate speed, since moment S, with 128 sampled points of the storage of the data after down-sampled, do relevant adding up with 3 time domain master synchronizing sequences respectively.

4, with starting point constantly S slide in the whole frame period, searched for a frame after, numbering in the group of the position at record correlation peaks place and corresponding master sync signal residential quarter ID thereof.

At this moment, the correlation peaks position is the original position of master sync signal, that is field sync information (5ms).

In step S102, by with Cyclic Prefix (Cyclic Prefix, CP) data and main synchronizing sequence end CP length data cross-correlation, determine the CP type.

According to the generative process of OFDM symbol as can be known, after finishing the IFFT computing, the data sequence of each OFDM symbol end CP length in the time domain need to be copied to before this symbol, therefore, the data sequence of the CP length before master sync signal namely is the data sequence of the CP length at master sync signal end.According to this feature, can determine the CP type by the method for the data sequence of the CP length at CP data sequence and main synchronizing sequence end being done cross-correlation, its idiographic flow is as follows:

1, respectively front 9 data sequences and front 32 data sequences of main synchronizing sequence correlation peaks position are preserved.

Because master sync signal is positioned at the 1st work song frame and the 6th work song frame of TDD-LTE radio frames, therefore in the situation that minimum bandwidth, the CP length under the conventional CP pattern is 9, and the CP length under the mode of extension is 32.

2, above-mentioned two data sequences are done relevant adding up with 9 data and 32 data at master sync signal end respectively, judge its higher value, can determine the CP type.That is, when the relevant accumulated value of 9 data was larger, this CP type was conventional CP type, and when the relevant accumulated value of 32 data was larger, this CP type was expansion CP type.

In the TDD-LTE system, auxiliary synchronous signals be 31 pseudo random sequence by two segment length by interweave, cascade consists of, lay respectively on last OFDM symbol of the 0th work song frame of radio frames and the 5th work song frame, because it is different with the secondary synchronization sequences of the 5th work song frame to be mapped to the 0th work song frame, therefore can get access to the border of 10ms by auxiliary synchronizing process, namely get access to the 10ms frame synchronization information.

In step S103, generate local scrambling sequence and auxiliary synchronous signals original series S (n), wherein, local scrambling sequence comprises the first scrambling sequence C ₀With the second scrambling sequence C ₁

Wherein, local scrambling sequence C ₀And C ₁Generation depend on master sync signal, by the m sequence

Cyclic shift generates:

$c_0\left(n\right)=\tilde{c}\left((n+N_{\mathrm{ID}}^{\left(2\right)})\mathrm{mod}31\right)$

$c_1\left(n\right)=\tilde{c}\left((n+N_{\mathrm{ID}}^{\left(2\right)}+3)\mathrm{mod}31\right)$

Wherein,

Be the interior numbering of group of residential quarter ID, finish owing to main synchronizing process this moment, therefore Definite.

The M sequence $\tilde{c}\left(i\right)=1-2x\left(i\right),$ 0≤i≤30， $x(\stackrel{\&OverBar;}{i}+5)=(x(\stackrel{\&OverBar;}{i}+3)+x\left(\stackrel{\&OverBar;}{i}\right))\mathrm{mod}2,$ $0\&le;\stackrel{\&OverBar;}{i}\&le;25,$ And the initial condition of x (i) is x (0)=0, x (1)=0, x (2)=0, x (3)=0, x (4)=1.

The generation of auxiliary synchronous signals original series S (n) is by the m sequence Two kinds of different cyclic shifts obtain:

$s_0^{\left(m_0\right)}\left(n\right)=\tilde{s}\left((n+m_0)\mathrm{mod}31\right)$

$s_1^{\left(m_1\right)}\left(n\right)=\tilde{s}\left((n+m_1)\mathrm{mod}31\right)$

The M sequence $\tilde{s}\left(i\right)=1-2x\left(i\right),$ 0≤i≤30， $x(\stackrel{\&OverBar;}{i}+5)=(x(\stackrel{\&OverBar;}{i}+2)+x\left(\stackrel{\&OverBar;}{i}\right))\mathrm{mod}2,$

And the initial condition of x (i) is x (0)=0, x (1)=0, x (2)=0, x (3)=0, x (4)=1.

Wherein, m ₀And m ₁Be derived from residential quarter ID group #

Its relation is as follows:

m ₀＝m′mod31

m ₁＝(m ₀+[m′/31]+1)mod31

$m^{\&prime;}=N_{\mathrm{ID}}^{\left(1\right)}+q(q+1)/2,$ $q=\left[\frac{N_{\mathrm{ID}}^{\left(1\right)}+q^{\&prime;}(q^{\&prime;}+1)/2}{30}\right],$ $q^{\&prime;}=[N_{\mathrm{ID}}^{\left(1\right)}/30]$

And residential quarter ID group #

With m ₀And m ₁Mapping relations can be referring to table 2.

Table 2

In step S104, according to master sync signal initial time and CP type, receive extraction time domain secondary synchronization sequences the signal from low rate, and the time domain secondary synchronization sequences is converted to the frequency domain secondary synchronization sequences.

In embodiments of the present invention, because the CP type is definite in step S102, therefore according to resulting correlation peaks position in the main synchronizing process, can calculate the position of secondary synchronization sequences in low rate reception signal, thereby extract the time domain secondary synchronization sequences.

After getting access to the time domain secondary synchronization sequences, by the time domain secondary synchronization sequences being carried out 128 FFT conversion, obtain the secondary synchronization sequences of frequency domain.

In step S105, with the deinterleaving of frequency domain secondary synchronization sequences, and by respectively with local scrambling sequence C ₀And C ₁Descrambling obtains even number sequence e (n) and odd number sequence o (n).

In step S106, even number sequence e (n) is carried out circular correlation with the auxiliary synchronous signals original series, the first displacement coordinate of the frequency domain secondary synchronization sequences that the record correlation peaks is corresponding.

In embodiments of the present invention, because even number sequence e (n) is through m by original series ₀The cyclic shift of position obtains, and because original series has good autocorrelation, therefore e (n) is done circular correlation with original series after, the first displacement coordinate of frequency domain secondary synchronization sequences that its correlation peaks is corresponding is m ₀

In step S107, according to the first displacement coordinate, generate the first scrambling sequence Wherein, the first scrambling sequence

By the m sequence

Cyclic shift generates:

$z_1^{\left(m_0\right)}\left(n\right)=\tilde{z}\left((n+\left(m_0\mathrm{mod}8\right))\mathrm{mod}31\right)$

The M sequence $\tilde{z}\left(i\right)=1-2x\left(i\right),$ 0≤i≤30，

$x(\stackrel{\&OverBar;}{i}+5)=(x(\stackrel{\&OverBar;}{i}+4)+x(\stackrel{\&OverBar;}{i}+2)+x(\stackrel{\&OverBar;}{i}+1)+x\left(\stackrel{\&OverBar;}{i}\right))\mathrm{mod}2,$ $0\&le;\stackrel{\&OverBar;}{i}\&le;25,$ Its initial condition is x (0)=0, x (1)=0, x (2)=0, x (3)=0, x (4)=1.

In step S108, with odd number sequence o (n) with After carrying out the descrambling second time, carry out circular correlation with auxiliary synchronous original series, the second displacement coordinate of the frequency domain secondary synchronization sequences that the record correlation peaks is corresponding.

In embodiments of the present invention, because odd number sequence o (n) is through m by original series ₁The cyclic shift of position obtains, and because original series has good autocorrelation, therefore o (n) is done circular correlation with original series after, the second displacement coordinate of frequency domain secondary synchronization sequences that its correlation peaks is corresponding is m ₁

Thus, in step S106 and step S108, only need to carry out 31 length and be 31 computing cross-correlation, can determine m ₀And m ₁, need to carry out 168 length than traditional auxiliary synchronizing process is 62 computing cross-correlation, has reduced widely operand, has improved down-going synchronous efficient, has alleviated system burden.

In step S109, according to the first displacement coordinate and the second displacement coordinate, obtain residential quarter ID group #, the relative position according to the first displacement coordinate and the second displacement coordinate calculates the frame start information.

In embodiments of the present invention, because the first displacement coordinate is the m through determining after synchronous ₀, the second displacement coordinate is the m through determining after synchronous ₁, therefore, according to m ₀And m ₁Can determine residential quarter ID group #, its residential quarter ID group # obtains equation and is:

And according to

Determine residential quarter ID.Simultaneously, according to m ₀And m ₁Relative position, can calculate the frame start information.

Fig. 2 shows the structure of the TDD-LTE downlink synchronization device that second embodiment of the invention provides, and for convenience of explanation, only shows the part relevant with the present embodiment.

With reference to Fig. 2, this downlink synchronization device has comprised:

Main lock unit 21 is used for master sync signal and reception Signal cross correlation, obtains the interior numbering of group of field sync information and residential quarter ID;

CP type determining unit 22 is used for cyclic prefix CP data and master sync signal end CP length data cross-correlation, determines the CP type;

Local scrambling sequence and auxiliary synchronous original series generation unit 23 are used for generating local scrambling sequence and auxiliary synchronous original series, and described local scrambling sequence comprises the first scrambling sequence and the second scrambling sequence;

Frequency domain secondary synchronization sequences acquiring unit 24 is used for according to master sync signal initial time and CP type, extracts the time domain secondary synchronization sequences, and is converted to the frequency domain secondary synchronization sequences;

Sequence of parity acquiring unit 25, be used for the deinterleaving of described frequency domain secondary synchronization sequences and respectively with described the first scrambling sequence and described the second scrambling sequence descrambling after, obtain respectively even number sequence and odd number sequence;

The first displacement coordinate acquiring unit 26 is used for described even number sequence and described auxiliary synchronous original series circular correlation, and the coordinate record that correlation peaks is corresponding is the first displacement coordinate;

The 3rd scrambling sequence generation unit 27 is used for generating the 3rd scrambling sequence according to described the first displacement coordinate;

The second displacement coordinate acquiring unit 28 is used for behind described odd number sequence and described the 3rd scrambling sequence descrambling, and with described auxiliary synchronous original series circular correlation, the coordinate record that correlation peaks is corresponding is the second displacement coordinate;

Residential quarter ID group # and frame start information acquiring unit 29, be used for according to described the first displacement coordinate and described the second displacement coordinate, obtain residential quarter ID group #, and according to the relative position of described the first displacement coordinate with described the second displacement coordinate, calculating frame start information.

And in main lock unit 21, specifically comprised:

Frequency domain master synchronizing sequence generates subelement 211, is used for generating 3 frequency domain master synchronizing sequences according to the Zadoff-Chu sequence;

Time domain master's synchronizing sequence generates subelement 212, is used for frequency domain master synchronizing sequence is converted to time domain master synchronizing sequence;

The first relevant cumulative subelement 213 is used for from the master sync signal initial time, with 128 sampled points of the reception signal storage after down-sampled, does relevant cumulative with 3 time domain master synchronizing sequences respectively;

Numbering is obtained subelement 214 in field sync information and the residential quarter ID group, be used for described initial time was slided in the whole frame period, the correlation peaks position is recorded as described field sync information, obtains simultaneously the interior numbering of group of residential quarter ID corresponding to described correlation peaks position.

And in CP type determining unit 22, specifically comprised:

Data are preserved subelement 221, are used for preserving respectively front 9 data and front 32 data of described correlation peaks position;

The second relevant cumulative subelement 222, front 9 data that are used for preserving are done relevant cumulative with 9 data and 32 data at master sync signal end respectively with front 32 data;

Relevant accumulation result comparing unit 223, the higher value of the accumulation result that is used for being correlated with is defined as corresponding CP type.

In the TDD-LTE down link synchronisation method that the TDD-LTE downlink synchronization device that second embodiment of the invention provides can use in aforementioned correspondence, details do not repeat them here referring to the associated description of the invention described above the first embodiment.

In embodiments of the present invention, by above-mentioned auxiliary synchronizing process, only need to carry out 31 length and be 31 computing cross-correlation, can determine m ₀And m ₁Thereby, obtain the down-going synchronous information of TDD-LTE, reduced widely operand, improved down-going synchronous efficient, alleviated system burden.

The above only is preferred embodiment of the present invention, not in order to limiting the present invention, all any modifications of doing within the spirit and principles in the present invention, is equal to and replaces and improvement etc., all should be included within protection scope of the present invention.

Claims (8)

1. a TDD-LTE down link synchronisation method is characterized in that, described method comprises the steps:

With master sync signal and reception Signal cross correlation, obtain the interior numbering of group of field sync information and residential quarter ID;

With cyclic prefix CP data and master sync signal end CP length data cross-correlation, determine the CP type;

Generate local scrambling sequence and auxiliary synchronous original series, described local scrambling sequence comprises the first scrambling sequence and the second scrambling sequence;

According to master sync signal initial time and CP type, extract the time domain secondary synchronization sequences, and be converted to the frequency domain secondary synchronization sequences;

With the deinterleaving of described frequency domain secondary synchronization sequences and respectively with described the first scrambling sequence and described the second scrambling sequence descrambling after, obtain respectively even number sequence and odd number sequence;

With described even number sequence and described auxiliary synchronous original series circular correlation, the coordinate record that correlation peaks is corresponding is the first displacement coordinate;

According to described the first displacement coordinate, generate the 3rd scrambling sequence;

Behind described odd number sequence and described the 3rd scrambling sequence descrambling, with described auxiliary synchronous original series circular correlation, the coordinate record that correlation peaks is corresponding is the second displacement coordinate;

According to described the first displacement coordinate and described the second displacement coordinate, obtain residential quarter ID group #, and according to the relative position of described the first displacement coordinate with described the second displacement coordinate, calculating frame start information.

2. the method for claim 1 is characterized in that, the described step of numbering in the group of field sync information and residential quarter ID of obtaining specifically comprises:

Generate 3 frequency domain master synchronizing sequences according to the Zadoff-Chu sequence, described Zadoff-Chu sequence is:

$d_u\left(n\right)=\left\{\begin{array}{cc}{e}^{-j\frac{\mathrm{\&pi;un}(n+1)}{63}}& n=\mathrm{0,1},...,30\\ e^{-j\frac{\mathrm{\&pi;u}(n+1)(n+2)}{63}}& n=\mathrm{31,32},...,61\end{array}\right.,$ Wherein, u is radical exponent, and in the group of residential quarter ID numbering 0,1,2 respectively the value of corresponding u be 25,29,34;

Frequency domain master synchronizing sequence is converted to time domain master synchronizing sequence;

From the master sync signal initial time, with 128 sampled points of the reception signal storage after down-sampled, do relevant cumulative with 3 time domain master synchronizing sequences respectively;

Described initial time was slided in the whole frame period, the correlation peaks position is recorded as described field sync information, obtain simultaneously the interior numbering of group of residential quarter ID corresponding to described correlation peaks position.

3. method as claimed in claim 2 is characterized in that, the step of described definite CP type specifically comprises:

Preserve respectively front 9 data and front 32 data of described correlation peaks position;

Respectively with 9 data and 32 data at master sync signal end do relevant cumulative with front 32 data front 9 data of preserving;

The higher value of relevant accumulation result is defined as corresponding CP type.

4. the method for claim 1 is characterized in that, described according to the first displacement coordinate, the formula that generates the 3rd scrambling sequence is: $z_1^{\left(m_0\right)}\left(n\right)=\tilde{z}\left((n+\left(m_0\mathrm{mod}8\right))\mathrm{mod}31\right),$ Wherein, Be the 3rd scrambling sequence, m ₀Be described the first displacement coordinate,

0≤i≤30, $x(\stackrel{\&OverBar;}{i}+5)=(x(\stackrel{\&OverBar;}{i}+4)+x(\stackrel{\&OverBar;}{i}+2)+x(\stackrel{\&OverBar;}{i}+1)+x\left(\stackrel{\&OverBar;}{i}\right))\mathrm{mod}2,$ $0\&le;\stackrel{\&OverBar;}{i}\&le;25,$ And initial condition is x (0)=0, x (1)=0, x (2)=0, x (3)=0, x (4)=1.

5. the method for claim 1 is characterized in that, the described equation that obtains residential quarter ID group # according to the first displacement coordinate and the second displacement coordinate is:

Wherein, m ₀Be described the first displacement coordinate, m ₁Be described the second displacement coordinate, Be described residential quarter ID group #.

6. a TDD-LTE downlink synchronization device is characterized in that, described device comprises:

Main lock unit is used for master sync signal and reception Signal cross correlation, obtains the interior numbering of group of field sync information and residential quarter ID;

CP type determining unit is used for cyclic prefix CP data and master sync signal end CP length data cross-correlation, determines the CP type;

Local scrambling sequence and auxiliary synchronous original series generation unit are used for generating local scrambling sequence and auxiliary synchronous original series, and described local scrambling sequence comprises the first scrambling sequence and the second scrambling sequence;

Frequency domain secondary synchronization sequences acquiring unit is used for according to master sync signal initial time and CP type, extracts the time domain secondary synchronization sequences, and is converted to the frequency domain secondary synchronization sequences;

The sequence of parity acquiring unit, be used for the deinterleaving of described frequency domain secondary synchronization sequences and respectively with described the first scrambling sequence and described the second scrambling sequence descrambling after, obtain respectively even number sequence and odd number sequence;

The first displacement coordinate acquiring unit is used for described even number sequence and described auxiliary synchronous original series circular correlation, and the coordinate record that correlation peaks is corresponding is the first displacement coordinate;

The 3rd scrambling sequence generation unit is used for generating the 3rd scrambling sequence according to described the first displacement coordinate;

The second displacement coordinate acquiring unit is used for behind described odd number sequence and described the 3rd scrambling sequence descrambling, and with described auxiliary synchronous original series circular correlation, the coordinate record that correlation peaks is corresponding is the second displacement coordinate;

Residential quarter ID group # and frame start information acquiring unit, be used for according to described the first displacement coordinate and described the second displacement coordinate, obtain residential quarter ID group #, and according to the relative position of described the first displacement coordinate with described the second displacement coordinate, calculating frame start information.

7. device as claimed in claim 6 is characterized in that, described main lock unit comprises:

Frequency domain master synchronizing sequence generates subelement, is used for generating 3 frequency domain master synchronizing sequences according to the Zadoff-Chu sequence;

Time domain master's synchronizing sequence generates subelement, is used for frequency domain master synchronizing sequence is converted to time domain master synchronizing sequence;

The first relevant cumulative subelement is used for from the master sync signal initial time, with 128 sampled points of the reception signal storage after down-sampled, does relevant cumulative with 3 time domain master synchronizing sequences respectively;

Numbering is obtained subelement in field sync information and the residential quarter ID group, be used for described initial time was slided in the whole frame period, the correlation peaks position is recorded as described field sync information, obtains simultaneously the interior numbering of group of residential quarter ID corresponding to described correlation peaks position.

8. device as claimed in claim 7 is characterized in that, described CP type determining unit comprises:

Data are preserved subelement, are used for preserving respectively front 9 data and front 32 data of described correlation peaks position;

The second relevant cumulative subelement, front 9 data that are used for preserving are done relevant cumulative with 9 data and 32 data at master sync signal end respectively with front 32 data;

Relevant accumulation result comparing unit, the higher value of the accumulation result that is used for being correlated with is defined as corresponding CP type.

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