CN103685120A - Resynchronization method and system for LTE system - Google Patents

Abstract

The invention discloses a resynchronization method and a resynchronization system for an LTE (long term evolution) system. The resynchronization method comprises the following steps: receiving a subframe at least containing a secondary synchronization signal; determining the position of the secondary synchronization signal according to a frame structure, and intercepting SSS data with the length of K/ M ahead of N/ M sampling points; downsampling and filtering by using the intercepted SSS data; judging whether a same-frequency adjacent region exists or not, and if so, eliminating interference according to the configured same-frequency adjacent region; performing secondary synchronization channel estimation on a measured cell according to the secondary synchronization signal from which same-frequency interference is eliminated, and acquiring a timing time of the secondary synchronization signal; according to the output timing time of the secondary synchronization signal, measuring again by using a cell-based reference signal, and measuring the output timing time as a final resynchronization timing output. Through the resynchronization method and the resynchronization system, the time needed in the resynchronization process of the LTE is greatly reduced, and the timing precision and the timing error range of resynchronization output are improved relatively highly.

Description

A kind of resynchronization method for LTE system and system

Technical field

The present invention relates to a kind of resynchronization method and system, particularly relate to a kind of resynchronization method for LTE system and system.

Background technology

Along with social development and progress, people require mobile terminal that voice and the text service of high-quality not only can be provided, and the digital multimedia application service of two-forty, large capacity and low delay can also be provided.In order to meet this growing demand of people, the end of the year 2004, third generation partner program (3GPP, 3rd Generation Partnership Project) has started Long Term Evolution (LTE, the Long Term Evolution) project of universal mobile telecommunications system technology.

In LTE system, terminal, before and after switching or when sleep is waken up, often needs to carry out Timing Synchronization with base station.In prior art, terminal heavy synchronous concrete steps in switching gravity treatment are as follows:

(1) receive that 1ms comprises PSS (Primary Synchronization Signal, master sync signal) and SSS (Secondary Synchronization Signal, auxiliary synchronous signals) data are carried out down-sampled filtering;

(2) according to frame timing and CP (Cyclic Prefix, Cyclic Prefix) type, determine SSS position, and shift to an earlier date 1 data that sampled point intercepted length is 128;

(3) judge whether to exist interfered cell, if there is interfered cell, perform step (4), otherwise execution step (5);

(4) according to disturbing cellid (cell number) to carry out auxiliary synchronization channel estimation, utilize auxiliary synchronization channel to estimate reconstruct interference signal, and disturb elimination, continue step (5);

(5) according to heavy synchronous cellid (cell number), carry out auxiliary synchronization channel estimation, obtain channel impulse response peak, peak is real SSS position.

Yet there is following shortcoming in the resynchronization method of above-mentioned switching gravity treatment:

(1) easily there is wrong position in reuse adoption process;

(2) timing accuracy of gravity treatment output is not high;

(3) the OTD2 scope of output is between-992Ts～32Ts, if local timing ratio network timing shifts to an earlier date when a lot, is easy to occur heavy synchronization timing output error.

In prior art, heavy when sleep is waken up of terminal is synchronously generally divided into following two processes:

One, synchronously descend PSS processing procedure:

(1) receiving length is that 1ms comprises PSS and SSS data, and carries out down-sampled filtering;

(2) carry out primary synchronization channel estimation, and back up corresponding channel impulse response power tap;

(3) channel impulse response is merged to processing;

(4) whether judgement is to receive for the last time data, is not to receive for the last time data, directly exit, otherwise execution step (5).

(5) carry out primary synchronization channel and estimate judgement, adjudicate successfully, synchronous lower PSS success is described, no person synchronously descends PSS procedure failure.

Two, SSS essence synchronizing process:

(1) call SSS channel estimation function and complete auxiliary synchronous channel estimation function;

(2) whether what pre-treatment was worked as in judgement is the K time SSS channel estimating, if not, directly exit, otherwise execution step (3);

(3) call SSS essence synchronization decisions function, the synchronous success of SSS essence is successfully described if adjudicate, otherwise exports unsuccessfully the PSS search procedure that (4) are changed frequency or reformed under next NID2.

Yet also there is following deficiency in resynchronization method when above-mentioned sleep is waken up:

(1) receive data often, affect the length of one's sleep;

(2) synchronously descend PSS output possibility more, can not very accurately determine PSS position corresponding to heavy synchronized cells, the SSS essence that therefore can affect for the 2nd stage is synchronous, causes weighing synchronous output error regularly;

(3) timing accuracy of output is not high.

Summary of the invention

The deficiency existing for overcoming above-mentioned prior art, the present invention's object is to provide a kind of resynchronization method for LTE system and system, and its time that heavy synchronizing process in LTE system is needed reduces greatly, meets actual application; Make timing accuracy and the timing error scope of heavy synchronous output all be greatly improved simultaneously.

For reaching above-mentioned and other object, the invention provides a kind of resynchronization method for LTE system, be applied to the terminal in LTE system, comprise the steps:

Step 1, reception one at least comprises the subframe of auxiliary synchronous signals;

Step 2, determines the position at auxiliary synchronous signals place according to frame structure, and the SSS data that N/M sampled point intercepted length is K/M in advance, N >=1 wherein, and M is with to receive bandwidth relevant, K/M >=128, and K/M satisfied 2 ⁿrelation;

Step 3, utilizes the SSS data of intercepting to carry out down-sampled filtering processing;

Step 4, judges whether to exist homogeneous-frequency adjacent-domain, if there is homogeneous-frequency adjacent-domain, enters step 5, otherwise enters step 6;

Step 5, disturbs elimination according to the homogeneous-frequency adjacent-domain of configuration;

Step 6, carries out the auxiliary synchronization channel estimation of tested community, the timing of obtaining auxiliary synchronous signals according to the auxiliary synchronous signals of eliminating after co-channel interference; And

Step 7, the timing according to the auxiliary synchronous signals of output, utilizes the reference signal based on community to measure again, measures the timing of output as final heavy synchronization timing output.

Further, step 4 also comprises the steps:

The auxiliary synchronous signals generating according to this locality carries out channel estimating, and the average power of the noise power of the maximum power value in front X the tap of calculating acquisition and Y tap;

According to the average power of the noise power of the maximum power value in a front X tap and Y tap, calculate peak-to-average force ratio; And

This peak-to-average force ratio and the threshold value that obtain are compared, if this peak-to-average force ratio is less than this threshold value, represents that community is very weak or do not exist, if this peak-to-average force ratio is greater than this threshold value, represent to exist strong co-channel interference adjacent area.

Further, this threshold value is more than or equal to 4.

Further, the calculating of this peak-to-average force ratio obtains by following formula:

${\mathrm{ratio}}_{\max /\mathrm{mean}}=\frac{{\mathrm{pow}}_{\max }}{{\mathrm{pow}}_{\mathrm{mean}}}$

Wherein, ratio _max/meanfor peak-to-average force ratio, pow _maxfor the maximum power value in a front X tap, pow _meanaverage power for the noise power of Y tap.

Further, X is that 64, Y is 128.

Further, step 5 also comprises the steps:

The local auxiliary synchronous signals generating according to the homogeneous-frequency adjacent-domain numbering of configuration calculates channel impulse, and therefrom chooses N ₁individual tap;

Calculate de-noising thresholding;

For the channel impulse lower than de-noising thresholding, carry out 0 processing clearly;

According to channel impulse, carry out auxiliary synchronous signals reconstruct, eliminate inter-frequency interference cell; And

Repeat said process, until all eliminate totally all configuration homogeneous-frequency adjacent-domains.

Further, N ₁value is between 1～32.

Further, in step 1, the subframe of reception is subframe 0 or subframe 5, and the data length of reception is at least the data length that 0.5ms adds 2 OFDM symbols.

Further, in step 3, down-sampled filtering is processed the desampling fir filter sample rate adopting and is not less than 0.96MHz.

For reaching above-mentioned and other object, the present invention also provides a kind of heavy synchro system for LTE system, is applied to the terminal in LTE system, at least comprises:

Receive module, for receiving a subframe that at least comprises auxiliary synchronous signals;

SSS location positioning module, according to frame structure, determine the position at auxiliary synchronous signals place, and the SSS data that N/M sampled point intercepted length is K/M are in advance for down-sampled filtering, N >=1 wherein, M is relevant to reception bandwidth, K/M >=128, and K/M meets 2 ⁿrelation;

Module is processed in down-sampled filtering, utilizes the SSS data of intercepting, carries out down-sampled filtering processing;

Co-channel interference is eliminated module, for judging whether to exist homogeneous-frequency adjacent-domain, with when judgement exists homogeneous-frequency adjacent-domain, disturbs elimination;

Auxiliary synchronization channel is estimated module, according to the auxiliary synchronous signals of eliminating after co-channel interference, carries out the auxiliary synchronization channel estimation of tested community, the timing of obtaining auxiliary synchronous signals; And

Measure module, the timing according to the auxiliary synchronous signals of output, utilizes the reference signal signal based on community to measure again, measures the timing of output as final heavy synchronization timing output.

Further, this co-channel interference elimination module also comprises:

Channel estimating module, the auxiliary synchronous signals generating according to this locality carries out channel estimating, and the average power of the noise power of the maximum power value in front X the tap of acquisition and Y tap;

Peak-to-average force ratio calculates module, according to the average power of the noise power of the maximum power value in front X the tap obtaining and Y tap, calculates peak-to-average force ratio;

Judgement module, compares this peak-to-average force ratio and a threshold value, to judge whether to exist strong co-channel interference adjacent area; And

Interference elimination treatment module, when this judgement module judgement exists strong co-channel interference adjacent area, disturbs elimination according to the homogeneous-frequency adjacent-domain of configuration.

Further, if peak-to-average force ratio is less than this threshold value, represents that this community is very weak or do not exist; If peak-to-average force ratio is greater than this threshold value, represent to exist strong co-channel interference adjacent area.

Further, this threshold value is more than or equal to 4.

Further, the subframe that this reception module receives is subframe 0 or subframe 5, and the data length of reception is at least the data length that 0.5ms adds 2 OFDM symbols.

Compared with prior art, a kind of resynchronization method for LTE system of the present invention and system, the subframe that comprises auxiliary synchronous signals by reception, auxiliary synchronous signals is carried out channel estimating and calculates peak-to-average force ratio, according to peak-to-average force ratio judgement co-channel interference and after eliminating interference, by auxiliary synchronization channel, estimate to obtain again the timing of auxiliary synchronous signals, realized terminal in LTE system switch before and after or the sleep object of waking up with base station Timing Synchronization, compared with prior art, the invention enables the time of heavy synchronous process need greatly to reduce, meet actual application; The timing accuracy of heavy synchronous output of the present invention is also greatly improved; Heavy synchronous timing error scope of the present invention is also greatly improved.

Accompanying drawing explanation

Fig. 1 is the flow chart of a kind of resynchronization method for LTE system of the present invention;

Fig. 2 is the position view of synchronizing signal in preferred embodiment of the present invention;

Fig. 3 is the flow chart to homogeneous-frequency adjacent-domain judgement in preferred embodiment of the present invention;

Fig. 4 is the system architecture diagram of a kind of heavy synchro system for LTE system of the present invention.

Embodiment

Below, by specific instantiation accompanying drawings embodiments of the present invention, those skilled in the art can understand other advantage of the present invention and effect easily by content disclosed in the present specification.The present invention also can be implemented or be applied by other different instantiation, and the every details in this specification also can be based on different viewpoints and application, carries out various modifications and change not deviating under spirit of the present invention.

Fig. 1 is the flow chart of a kind of resynchronization method for LTE system of the present invention.As shown in Figure 1, a kind of resynchronization method for LTE system of the present invention, comprises the steps:

Step 101, terminal receives a subframe that comprises SSS (auxiliary synchronous signals), and the data length of reception be take and at least comprised auxiliary synchronous signals as lower limit.

Fig. 2 is the position view of synchronizing signal in preferred embodiment of the present invention.Visible, auxiliary synchronous signals (SSS) is positioned at subframe 0 and subframe 5 last symbol of a radio frames, therefore in preferred embodiment of the present invention, terminal receives subframe 0 or subframe 5 data, the data length receiving is at least the data length that 0.5ms adds 2 OFDM symbols, comprises auxiliary synchronous signals (SSS) in the data that can guarantee like this to receive.

Step 102, according to frame structure, determine the position at SSS place, the SSS data that N/M sampled point intercepted length is K/M are in advance for down-sampled filtering, N >=1 wherein, M is relevant to reception bandwidth, its value can be with reference to table 1 below, K/M >=128, and K/M meets 2 ⁿrelation.

Wherein, in table 1, for 15MHz bandwidth, for fear of 1536 FFT, process, adopt the sample rate identical with 20MHz bandwidth, use 2048 FFT

System bandwidth [MHz]	1.4	3	5	10	15	20
							Baseband sampling rate [MHz]	1.92	3.84	7.68	15.36	30.72	30.72
The every subframe sampling number of one circuit-switched data	1920	3840	7680	15360	30720	30720
							Sample rate normalization coefficient M	16	8	4	2	1	1
FFT points N	128	256	512	1024	2048	2048
							The sampling number of Normal CP	9	18	36	72	144	144
The sampling number of Extended CP	32	64	128	256	512	512

Table 1

Step 103, utilizes the SSS data that intercept, and carries out down-sampled filtering processing, and at this, down-sampled filtering is processed the desampling fir filter sample rate adopting and is not less than 0.96MHz, and the data length of down-sampled rear output is K/2*M;

Step 104, judges whether to exist homogeneous-frequency adjacent-domain, if there is homogeneous-frequency adjacent-domain, enters step 105, otherwise enters step 106;

Fig. 3 is the flow chart to homogeneous-frequency adjacent-domain judgement in preferred embodiment of the present invention.As shown in Figure 3, judge whether to exist the method for homogeneous-frequency adjacent-domain to comprise the steps:

Step S1, the auxiliary synchronous signals first generating according to this locality carries out channel estimating, and calculates the maximum power value pow obtaining in front X tap _maxand the average power pow of the noise power of Y tap _mean.Suppose to receive signal after down-sampled, can be expressed as:

${\stackrel{=}{e}}_{\mathrm{SCHE}}={[{\stackrel{=}{e}}_{\mathrm{SCHE}}\left(0\right),{\stackrel{=}{e}}_{\mathrm{SCHE}}\left(1\right),\·\·\·,{\stackrel{=}{e}}_{\mathrm{SCHE}}(K/2*M-1)]}^T$

Local synchronization code can be expressed as:

$d_{\mathrm{Local}}^{\mathrm{Time}}={[d_{\mathrm{Local}}^{\mathrm{Time}}\left(0\right),d_{\mathrm{Local}}^{\mathrm{Time}}\left(1\right),\·\·\·,d_{\mathrm{Local}}^{\mathrm{Time}}\left(63\right)]}^T$

By secondary synchronization sequences

after expansion, utilize FFT (fast Fourier transform) calculating linear correlation can obtain SSS channel estimation results as follows

${\stackrel{\‾}{r}}_{\mathrm{SCHE}}=\mathrm{IFFT}(\mathrm{FFT}\left({\stackrel{=}{e}}_{\mathrm{SCHE}}\right)\×\mathrm{conj}\left(\mathrm{FFT}\left({\stackrel{\‾}{d}}_{\mathrm{Local}}^{\mathrm{Time}}\right)\right))$

Wherein ${\stackrel{\‾}{d}}_{\mathrm{Local}}^{\mathrm{Time}}\left(j\right)=\left\{\begin{array}{cc}{d}_{\mathrm{Local}}^{\mathrm{Time}}\left(j\right)& \mathrm{if}0\≤j\≤63\\ 0& \mathrm{if}64\≤j\≤(K/2*M-1)\end{array}\right..$

The channel impulse response of SSS channel estimating can be expressed as:

${\stackrel{\‾}{r}}_{\mathrm{SCHE}}={[{\stackrel{\‾}{r}}_{\mathrm{SCHE}}\left(0\right),{\stackrel{\‾}{r}}_{\mathrm{SCHE}}\left(1\right),\·\·\·,{\stackrel{\‾}{r}}_{\mathrm{SCHE}}(K/2*M)]}^T$

Channel impulse response power tap can be expressed as:

P＝[p(0)，p(1)，…，p(K/2*M)] ^T

Wherein:

$p\left(i\right)={\left|{\stackrel{\&OverBar;}{r}}_{\mathrm{SCHE}}\left(i\right)\right|}^2,0<=i<K/2*M$

64 taps are in the past example, choose maximum power value pow in 64 taps above _maxand corresponding position pos _max

pow _max＝max(p(i))，i＝0，1，…，K/2*M-1

${\mathrm{pos}}_{\max }=\arg \underset{i}{\max }\left(p\left(i\right)\right),i=\mathrm{0,1},\&CenterDot;\&CenterDot;\&CenterDot;,K/2*M-1$

From 128 taps, choose noise power pow _noise, be formulated as:

${\mathrm{pow}}_{\mathrm{noise}}=\left\{\begin{array}{cc}[p\left(0\right),...,p({\mathrm{pos}}_{\max }-16),p({\mathrm{pos}}_{\max }+16),...,p(K/2*M)]& {\mathrm{pos}}_{\max }\&GreaterEqual;16\\ [p({\mathrm{pos}}_{\max }+16),...,p_{\mathrm{noise}}(K/2*M)]& {\mathrm{pos}}_{\max }<16\end{array}\right.$

The average power pow of calculating noise power _mean

pow _mean＝mean(pow _noise)

Preserve maximum power value pow _maxand corresponding position, for subsequent process, use.

Step S2, according to the maximum power value pow in a front X tap _maxand the average power pow of the noise power of Y tap _mean, calculate peak-to-average force ratio ratio _max/mean, be formulated as:

${\mathrm{ratio}}_{\max /\mathrm{mean}}=\frac{{\mathrm{pow}}_{\max }}{{\mathrm{pow}}_{\mathrm{mean}}}$

Step S3, peak-to-average force ratio ratio _max/meancompare with threshold value, if be less than thresholding, represent that this community is very weak or do not exist, the very weak or non-existent thresholding span in judgement community is more than or equal to 4, recommended value is set as 16, if be greater than threshold value, illustrate and have strong co-channel interference adjacent area, need to carry out interference elimination treatment to strong co-channel interference adjacent area.

Step 105, disturbs elimination according to the homogeneous-frequency adjacent-domain of configuration.

According to the homogeneous-frequency adjacent-domain ID (numbering) of configuration, generating local SSS sequence calculating channel impulse is expressed as power maximum p wherein _maxwith correspondence position pos _max', from wherein choosing N _{tap_num}individual tap,

${\hat{h}}_{\mathrm{SCHE}}\left(i\right)=\left\{\begin{array}{cc}{\stackrel{\&OverBar;}{r}}_{\mathrm{SCHE}}\left(i\right)& {{\mathrm{pos}}_{\max }}^{\&prime;}\&GreaterEqual;\frac{N_{\mathrm{tap}\_\mathrm{num}}}{2},({{\mathrm{pos}}_{\max }}^{\&prime;}-\frac{N_{\mathrm{tap}\_\mathrm{num}}}{2})\&le;i\&le;({{\mathrm{pos}}_{\max }}^{\&prime;}+\frac{N_{\mathrm{tap}\_\mathrm{num}}}{2})\\ {\stackrel{\&OverBar;}{r}}_{\mathrm{SCHE}}\left(i\right)& 0<{{\mathrm{pos}}_{\max }}^{\&prime;}<\frac{N_{\mathrm{tap}\_\mathrm{num}}}{2},({{\mathrm{pos}}_{\max }}^{\&prime;}-1)\&le;i\&le;({{\mathrm{pos}}_{\max }}^{\&prime;}+(N_{\mathrm{tap}\_\mathrm{num}}-1))\\ {\stackrel{\&OverBar;}{r}}_{\mathrm{SCHE}}\left(i\right)& {{\mathrm{pos}}_{\max }}^{\&prime;}=0,{{\mathrm{pos}}_{\max }}^{\&prime;}\&le;i\&le;({{\mathrm{pos}}_{\max }}^{\&prime;}+N_{\mathrm{tap}\_\mathrm{num}})\\ & \end{array}\right.$

N _{tap_num}value is between 1～32, and suggestion value is 5.

Calculate de-noising thresholding:

$P_{\mathrm{noise}\_\mathrm{th}}=\max (\frac{p_{\max }}{8},\frac{{\mathrm{pow}}_{\max }}{8})$

For lower than P _{noise_th}carry out 0 processing clearly

${\hat{h}}_{\mathrm{SCHE}}\left(i\right)=\left\{\begin{array}{cc}{\hat{h}}_{\mathrm{SCHE}}\left(i\right)& p\left(i\right)>P_{\mathrm{noise}\_\mathrm{<figure-callout\; id="0"\; label="th"\; filenames="HDA00002136105100021.png"\; state="\{\{state\}\}">th</figure-callout>}}\\ 0& \mathrm{others}\end{array}\right.,0<=i<N_{\mathrm{tap}\_\mathrm{num}}$

Then basis then, carry out SSS signal reconstruction, eliminate co-channel interference adjacent area.Repeating step 105, until all eliminate all configuration homogeneous-frequency adjacent-domains totally.

Step 106, carries out the auxiliary synchronization channel estimation of tested community according to the SSS signal of eliminating after co-channel interference, and the timing of obtaining SSS is similar with the processing in step 103.

Step 107, the timing according to the SSS of output, utilizes CRS (reference signal based on community) signal to do one-shot measurement again, measures the timing of output as final heavy synchronization timing output.

Fig. 4 is the system architecture diagram of a kind of heavy synchro system for LTE system of the present invention.As shown in Figure 4, a kind of heavy synchro system for LTE system of the present invention, the terminal that is applied to LTE system, at least comprises: receive module 40, SSS location positioning module 41, down-sampled filtering processing module 42, co-channel interference elimination module 43, auxiliary synchronization channel estimation module 44 and measure module 45.

Wherein, receive module 40 for receiving a subframe that at least comprises auxiliary synchronous signals (SSS), the data length receiving is limited at least to comprise auxiliary synchronous signals, in preferred embodiment of the present invention, receive the data that module 40 receives subframe 0 or subframe 5, the data length of reception is at least the data length that 0.5ms adds 2 OFDM symbols; SSS location positioning module 41 is determined the position at SSS place according to frame structure, and the SSS data that N/M sampled point intercepted length is K/M are in advance for down-sampled filtering, N >=1 wherein, M is relevant to reception bandwidth, its value can reference table 1, K/M >=128, and K/M meets 2 ⁿrelation; The SSS data that module 42 utilizes intercepting are processed in down-sampled filtering, carry out down-sampled filtering processing, and at this, down-sampled filtering is processed the desampling fir filter sample rate adopting and is not less than 0.96MHz, and the data length of down-sampled rear output is K/2*M; Co-channel interference is eliminated module 43 for judging whether to exist homogeneous-frequency adjacent-domain, with when judgement exists homogeneous-frequency adjacent-domain, disturbs elimination; Auxiliary synchronization channel estimates that module 44 carries out the auxiliary synchronization channel estimation of tested community, the timing of obtaining SSS according to the SSS signal of eliminating after co-channel interference; Measure module 45 according to the timing of the SSS of output, again utilize CRS (reference signal of tested community) signal to do one-shot measurement, measure the timing of output as final heavy synchronization timing output.

In preferred embodiment of the present invention, co-channel interference is eliminated module 43 and is also comprised that channel estimating module 430, peak-to-average force ratio calculate module 431, judgement module 432 and interference elimination treatment module 433.

Wherein, the auxiliary synchronous signals that channel estimating module 430 generates according to this locality carries out channel estimating, the average power of the maximum power value before obtaining in X tap and the noise power of Y tap.Specifically, suppose to receive signal after down-sampled, can be expressed as:

${\stackrel{=}{e}}_{\mathrm{SCHE}}={[{\stackrel{=}{e}}_{\mathrm{SCHE}}\left(0\right),{\stackrel{=}{e}}_{\mathrm{SCHE}}\left(1\right),\&CenterDot;\&CenterDot;\&CenterDot;,{\stackrel{=}{e}}_{\mathrm{SCHE}}(K/2*M-1)]}^T$

Local synchronization code can be expressed as:

$d_{\mathrm{Local}}^{\mathrm{Time}}={[d_{\mathrm{Local}}^{\mathrm{Time}}\left(0\right),d_{\mathrm{Local}}^{\mathrm{Time}}\left(1\right),\&CenterDot;\&CenterDot;\&CenterDot;,d_{\mathrm{Local}}^{\mathrm{Time}}\left(63\right)]}^T$

By secondary synchronization sequences (auxiliary synchronous signals SSS)

after expansion, utilize FFT (fast Fourier transform) calculating linear correlation can obtain SSS channel estimation results as follows

${\stackrel{\&OverBar;}{r}}_{\mathrm{SCHE}}=\mathrm{IFFT}(\mathrm{FFT}\left({\stackrel{=}{e}}_{\mathrm{SCHE}}\right)\&times;\mathrm{conj}\left(\mathrm{FFT}\left({\stackrel{\&OverBar;}{d}}_{\mathrm{Local}}^{\mathrm{Time}}\right)\right))$

Wherein ${\stackrel{\&OverBar;}{d}}_{\mathrm{Local}}^{\mathrm{Time}}\left(j\right)=\left\{\begin{array}{cc}{d}_{\mathrm{Local}}^{\mathrm{Time}}\left(j\right)& \mathrm{if}0\&le;j\&le;63\\ 0& \mathrm{if}64\&le;j\&le;(K/2*M-1)\end{array}\right..$

The channel impulse response of SSS channel estimating can be expressed as:

${\stackrel{\&OverBar;}{r}}_{\mathrm{SCHE}}={[{\stackrel{\&OverBar;}{r}}_{\mathrm{SCHE}}\left(0\right),{\stackrel{\&OverBar;}{r}}_{\mathrm{SCHE}}\left(1\right),\&CenterDot;\&CenterDot;\&CenterDot;,{\stackrel{\&OverBar;}{r}}_{\mathrm{SCHE}}(K/2*M)]}^T$

Channel impulse response power tap can be expressed as:

P＝[p(0)，p(1)，…，p(K/2*M)] ^T

Wherein:

$p\left(i\right)={\left|{\stackrel{\&OverBar;}{r}}_{\mathrm{SCHE}}\left(i\right)\right|}^2,0<=i<K/2*M$

64 taps were example in the past, chose maximum power value pow in 64 taps above _maxand corresponding position pos _max

pow _max＝max(p(i))，i＝0，1，…，K/2*M-1

${\mathrm{pos}}_{\max }=\arg \underset{i}{\max }\left(p\left(i\right)\right),i=\mathrm{0,1},\&CenterDot;\&CenterDot;\&CenterDot;,K/2*M-1$

From 128 taps, choose noise power pow _noise, be formulated as:

${\mathrm{pow}}_{\mathrm{noise}}=\left\{\begin{array}{cc}[p\left(0\right),...,p({\mathrm{pos}}_{\max }-16),p({\mathrm{pos}}_{\max }+16),...,p(K/2*M)]& {\mathrm{pos}}_{\max }\&GreaterEqual;16\\ [p({\mathrm{pos}}_{\max }+16),...,p_{\mathrm{noise}}(K/2*M)]& {\mathrm{pos}}_{\max }<16\end{array}\right.$

The average power pow of calculating noise power _mean

pow _mean＝mean(pow _noise)

Preserve maximum power value pow _maxand corresponding position, for subsequent process, use.

Peak-to-average force ratio calculates module 431 according to the maximum power value pow in front X the tap obtaining _maxand the average power pow of the noise power of Y tap _meancalculate peak-to-average force ratio ratio _max/mean, be formulated as:

${\mathrm{ratio}}_{\max /\mathrm{mean}}=\frac{{\mathrm{pow}}_{\max }}{{\mathrm{pow}}_{\mathrm{mean}}}.$

Judgement module 432 is by this peak-to-average force ratio ratio _max/meancompare with threshold value, to judge whether having strong co-channel interference adjacent area, if peak-to-average force ratio ratio _max/meanbe less than threshold value, represent that this community is very weak or do not exist, the very weak or non-existent thresholding span in judgement community is more than or equal to 4, and recommended value is set as 16, if peak-to-average force ratio ratio _max/meanbe greater than threshold value, illustrate and have strong co-channel interference adjacent area, need to carry out interference elimination treatment to strong co-channel interference adjacent area.

Interference elimination treatment module 433 is when there is strong co-channel interference adjacent area in 432 judgements of judgement module, according to the homogeneous-frequency adjacent-domain of configuration, disturb elimination, specifically, first according to the homogeneous-frequency adjacent-domain ID (numbering) of configuration, generate local SSS sequence and calculate channel impulse, be expressed as

power maximum p wherein _maxwith correspondence position pos _max', from wherein choosing N _{tap_num}individual tap,

${\hat{h}}_{\mathrm{SCHE}}\left(i\right)=\left\{\begin{array}{cc}{\stackrel{\&OverBar;}{r}}_{\mathrm{SCHE}}\left(i\right)& {{\mathrm{pos}}_{\max }}^{\&prime;}\&GreaterEqual;\frac{N_{\mathrm{tap}\_\mathrm{num}}}{2},({{\mathrm{pos}}_{\max }}^{\&prime;}-\frac{N_{\mathrm{tap}\_\mathrm{num}}}{2})\&le;i\&le;({{\mathrm{pos}}_{\max }}^{\&prime;}+\frac{N_{\mathrm{tap}\_\mathrm{num}}}{2})\\ {\stackrel{\&OverBar;}{r}}_{\mathrm{SCHE}}\left(i\right)& 0<{{\mathrm{pos}}_{\max }}^{\&prime;}<\frac{N_{\mathrm{tap}\_\mathrm{num}}}{2},({{\mathrm{pos}}_{\max }}^{\&prime;}-1)\&le;i\&le;({{\mathrm{pos}}_{\max }}^{\&prime;}+(N_{\mathrm{tap}\_\mathrm{num}}-1))\\ {\stackrel{\&OverBar;}{r}}_{\mathrm{SCHE}}\left(i\right)& {{\mathrm{pos}}_{\max }}^{\&prime;}=0,{{\mathrm{pos}}_{\max }}^{\&prime;}\&le;i\&le;({{\mathrm{pos}}_{\max }}^{\&prime;}+N_{\mathrm{tap}\_\mathrm{num}})\\ & \end{array}\right.$

N _{tap_num}value is between 1～32, and suggestion value is 5.

Calculate de-noising thresholding:

$P_{\mathrm{noise}\_\mathrm{th}}=\max (\frac{p_{\max }}{8},\frac{{\mathrm{pow}}_{\max }}{8})$

For lower than P _{noise_th}carry out 0 processing clearly

${\hat{h}}_{\mathrm{SCHE}}\left(i\right)=\left\{\begin{array}{cc}{\hat{h}}_{\mathrm{SCHE}}\left(i\right)& p\left(i\right)>P_{\mathrm{noise}\_\mathrm{<figure-callout\; id="0"\; label="th"\; filenames="HDA00002136105100021.png"\; state="\{\{state\}\}">th</figure-callout>}}\\ 0& \mathrm{others}\end{array}\right.,0<=i<N_{\mathrm{tap}\_\mathrm{num}}$

Then basis then,

carry out SSS signal reconstruction, eliminate co-channel interference adjacent area.Repeat this interference elimination treatment until all configuration homogeneous-frequency adjacent-domains are all eliminated totally.

Visible, a kind of resynchronization method for LTE system of the present invention and system, the subframe that comprises auxiliary synchronous signals by reception, auxiliary synchronous signals is carried out channel estimating and calculates peak-to-average force ratio, according to peak-to-average force ratio judgement co-channel interference and after eliminating interference, by auxiliary synchronization channel, estimate to obtain again the timing of auxiliary synchronous signals, realized terminal in LTE system switch before and after or the sleep object of waking up with base station Timing Synchronization, and, compared with prior art, the invention enables heavy synchronizing process required time obviously to reduce, in the situation that not affecting performance, by originally receiving 5 secondary data data, be reduced to 1 secondary data, processing time shortens to 5ms by original 27ms, meet practical application, meanwhile, the timing accuracy of heavy synchronous output of the present invention is more accurate, and timing accuracy of the present invention can be as accurate as the (T wherein of 1 GeTS unit _s=1/ (15000 * 2048)), and before the present invention, heavy synchronous output regularly unit be 32TS integral multiple, timing error scope of the present invention is also greatly improved, and before the present invention, timing error scope is less than 1km, and timing error scope of the present invention is at least 10km.

Above-described embodiment is illustrative principle of the present invention and effect thereof only, but not for limiting the present invention.Any those skilled in the art all can, under spirit of the present invention and category, modify and change above-described embodiment.Therefore, the scope of the present invention, should be as listed in claims.

Claims (14)

1. for a resynchronization method for LTE system, be applied to the terminal in LTE system, comprise the steps:

Step 1, reception one at least comprises the subframe of auxiliary synchronous signals;

Step 2, determines the position at auxiliary synchronous signals place according to frame structure, and the SSS data that N/M sampled point intercepted length is K/M in advance, N >=1 wherein, and M is with to receive bandwidth relevant, K/M >=128, and K/M satisfied 2 ⁿrelation;

Step 3, utilizes the SSS data of intercepting to carry out down-sampled filtering processing;

Step 4, judges whether to exist homogeneous-frequency adjacent-domain, if there is homogeneous-frequency adjacent-domain, enters step 5, otherwise enters step 6;

Step 5, disturbs elimination according to the homogeneous-frequency adjacent-domain of configuration;

Step 6, carries out the auxiliary synchronization channel estimation of tested community, the timing of obtaining auxiliary synchronous signals according to the auxiliary synchronous signals of eliminating after co-channel interference; And

Step 7, the timing according to the auxiliary synchronous signals of output, utilizes the reference signal of tested community to measure again, measures the timing of output as final heavy synchronization timing output.

2. the resynchronization method for LTE system as claimed in claim 1, is characterized in that, step 4 also comprises the steps:

The auxiliary synchronous signals generating according to this locality carries out channel estimating, and the average power of the noise power of the maximum power value in front X the tap of calculating acquisition and Y tap;

According to the average power of the noise power of the maximum power value in a front X tap and Y tap, calculate peak-to-average force ratio; And

This peak-to-average force ratio and the threshold value that obtain are compared, if this peak-to-average force ratio is less than this threshold value, represents that community is very weak or do not exist, if this peak-to-average force ratio is greater than this threshold value, represent to exist strong co-channel interference adjacent area.

3. the resynchronization method for LTE system as claimed in claim 2, is characterized in that: this threshold value is more than or equal to 4.

4. the resynchronization method for LTE system as claimed in claim 2, is characterized in that, the calculating of this peak-to-average force ratio obtains by following formula:

${\mathrm{ratio}}_{\max /\mathrm{mean}}=\frac{{\mathrm{pow}}_{\max }}{{\mathrm{pow}}_{\mathrm{mean}}}$

Wherein, ratio _max/meanfor peak-to-average force ratio, pow _maxfor the maximum power value in a front X tap, pow _meanaverage power for the noise power of Y tap.

5. the resynchronization method for LTE system as claimed in claim 4, is characterized in that: X is that 64, Y is 128.

6. the resynchronization method for LTE system as claimed in claim 1, is characterized in that, step 5 also comprises the steps:

The local auxiliary synchronous signals generating according to the homogeneous-frequency adjacent-domain numbering of configuration calculates channel impulse, and therefrom chooses N ₁individual tap;

Calculate de-noising thresholding;

For the channel impulse lower than de-noising thresholding, carry out 0 processing clearly;

According to channel impulse, carry out auxiliary synchronous signals reconstruct, eliminate inter-frequency interference cell; And

Repeat said process, until all eliminate totally all configuration homogeneous-frequency adjacent-domains.

7. the resynchronization method for LTE system as claimed in claim 6, is characterized in that: N ₁value is between 1～32.

8. the resynchronization method for LTE system as claimed in claim 1, is characterized in that: in step 1, the subframe of reception is subframe 0 or subframe 5, and the data length of reception is at least the data length that 0.5ms adds 2 OFDM symbols.

9. the resynchronization method for LTE system as claimed in claim 1, is characterized in that: in step 3, down-sampled filtering is processed the desampling fir filter sample rate adopting and is not less than 0.96MHz.

10. for a heavy synchro system for LTE system, be applied to the terminal in LTE system, at least comprise:

Receive module, for receiving a subframe that at least comprises auxiliary synchronous signals;

SSS location positioning module, according to frame structure, determine the position at auxiliary synchronous signals place, and the SSS data that N/M sampled point intercepted length is K/M are in advance for down-sampled filtering, N >=1 wherein, M is relevant to reception bandwidth, K/M >=128, and K/M meets 2 ⁿrelation;

Module is processed in down-sampled filtering, utilizes the SSS data of intercepting, carries out down-sampled filtering processing;

Co-channel interference is eliminated module, for judging whether to exist homogeneous-frequency adjacent-domain, with when judgement exists homogeneous-frequency adjacent-domain, disturbs elimination;

Auxiliary synchronization channel is estimated module, according to the auxiliary synchronous signals of eliminating after co-channel interference, carries out the auxiliary synchronization channel estimation of tested community, the timing of obtaining auxiliary synchronous signals; And

Measure module, the timing according to the auxiliary synchronous signals of output, utilizes the reference signal signal based on community to measure again, measures the timing of output as final heavy synchronization timing output.

11. a kind of heavy synchro systems for LTE system as claimed in claim 10, is characterized in that, this co-channel interference is eliminated module and also comprised:

Channel estimating module, the auxiliary synchronous signals generating according to this locality carries out channel estimating, and the average power of the noise power of the maximum power value in front X the tap of acquisition and Y tap;

Peak-to-average force ratio calculates module, according to the average power of the noise power of the maximum power value in front X the tap obtaining and Y tap, calculates peak-to-average force ratio;

Judgement module, compares this peak-to-average force ratio and a threshold value, to judge whether to exist strong co-channel interference adjacent area; And

Interference elimination treatment module, when this judgement module judgement exists strong co-channel interference adjacent area, disturbs elimination according to the homogeneous-frequency adjacent-domain of configuration.

12. a kind of heavy synchro systems for LTE system as claimed in claim 11, is characterized in that: if peak-to-average force ratio is less than this threshold value, represents that this community is very weak or do not exist; If peak-to-average force ratio is greater than this threshold value, represent to exist strong co-channel interference adjacent area.

13. a kind of heavy synchro systems for LTE system as claimed in claim 11, is characterized in that: this threshold value is more than or equal to 4.

14. a kind of heavy synchro systems for LTE system as claimed in claim 11, is characterized in that: the subframe that this reception module receives is subframe 0 or subframe 5, and the data length of reception is at least the data length that 0.5ms adds 2 OFDM symbols.

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