CN102347925B - Synchronization symbol detection method and apparatus thereof - Google Patents

Abstract

The invention provides a synchronization symbol detection method for a signal after AD conversion outputted by an automatic gain control (AGC) unit in a TDD (Time Division Duplex) system and an apparatus thereof. The method comprises the following steps: based on obtained difference between present AGC gain and predetermined object gain from the AGC unit, compensating AGC gain change of a signal going through down-sampling after AD conversion so as to obtain a sampling signal of stationary amplitude; with regards to each sample point of the compensated sampling signal, carrying out normalization on the sample point by utilizing statistical values of all sample points in a corresponding normalization window with the sample point as a center to obtain a normalization signal; carrying out synchronization symbol detection on the normalization signal in order to determine position and type of a synchronization symbol in the normalization signal. According to the invention, through carrying out pretreatment on a signal after automatic gain adjustment, signal amplitude fluctuation brought by amplifier gain adjustment can be substantially reduced, and quality of subsequent synchronization symbol detection is guaranteed.

Description

Detect the method and apparatus of synchronizing symbol

Technical field

Present invention relates in general to the communications field.More specifically, the present invention relates at TDD system especially TDD-LTE (Time Division Duplex-Long Term Evolution, time division duplex-Long Term Evolution) from Received signal strength, detect the method and apparatus of synchronizing symbol (Synchronization symbol, SS) in system.

Background technology

In wireless communication system, due to the fading effect of wireless channel, will cause Received signal strength amplitude fluctuates widely.In order to ensure the precision after signal quantization, terminal needs to use automatic growth control (Auto gain control) unit to carry out the change of dynamically tracking signal usually.According to the working range of analog digital converter (Analog digital converter, ADC), when received signals are weaker, the gain of amplifier is improved, the gain of step-down amplifier when Received signal strength is too high.The measurement of AGC and adjustment need to carry out based on the frame structure of Received signal strength, to ensure that the adjustment of amplifier gain can not bring additional distortion to Received signal strength.The adjustment of AGC has a great impact for the quality of the synchronous detection carried out in the synchronizing process between terminal and base station.

(Long term evaluation in 3GPP long evolving system, LTE), there is TDD mode (Time Division Duplex, TDD) and mode of frequency division duplexing (Frequency Division Duplex, FDD).In mode of frequency division duplexing wherein, uplink and downlink signals transmits at different frequencies.And the uplink and downlink signals of TDD mode transmits in the different time sections of same carrier frequency.

In LTE (TDD-LTE) system of TDD mode, Received signal strength realizes acquisition that is synchronous and Cell Synchronization Symbol type by relevant to the time domain of local synchronization symbol.Therefore, in the application, after receiving signal, need to detect synchronizing symbol from Received signal strength.In TDD-LTE system, there are seven kinds of frame structure configurations as shown in table 1.Identify descending sub frame with " D " in table 1, " U " identifies sub-frame of uplink, and " S " identifies special subframe.Each subframe lengths is 1ms, and the slot being 0.5ms by two length forms.As shown in table 1, main synchronizing symbol (Primary synchronization symbol, PSS) be arranged in the subframe that subframe sequence number is 1 and 6, auxiliary synchronizing symbol (Secondary synchronization symbol, SSS) is arranged in the subframe that subframe sequence number is 0 and 5.Figure 10 gives the tdd frame structure of half subframe, and wherein subframe SF#1 (sequence number is the subframe of 1) is special subframe, and subframe SF#1 is made up of descending time slot DwPTS, up-downgoing conversion interval GP and ascending time slot UpPTS.In Figure 10, PSS is positioned at the 3rd symbol of descending time slot DwPTS, and SSS is positioned at last symbol of subframe SF#0 (sequence number is the subframe of 0).Cell searching utilizes and obtains frame timing and community ID to the detection of these two synchronizing symbols.

Table 1

PSS to be length be 62 Zadoff-Chu sequence (k=0,1 ..., 61), have three.

$c_{n_{\mathrm{ZC}}}\left(k\right)=\left\{\begin{array}{c}\exp \{-\mathrm{j\π}{n}_{\mathrm{ZC}}\frac{k(k+1)}{63}\},k=\mathrm{0,1},\·\·\·,30\\ \exp \{-\mathrm{j\π}{n}_{\mathrm{ZC}}\frac{(k+1)(k+2)}{63}\},k=\mathrm{31,32},\·\·\·,61\end{array}\right.$

Wherein, n _zCget { one of 25,29,34}.Figure 11 shows and adjust PSS on carrier wave.As shown in figure 11, on each 31 subcarriers in this sequence left and right centered by DC, corresponding DC subcarrier zero setting.Five same zero setting of subcarrier on sequence both sides.Totally 72 subcarriers correspond to six RB (resource block, Resource Block) at center.Identical in the PSS sequence of subframe SF#1 and subframe SF#6.

The detection of PSS adopts the detection method based on matched filtering usually, when not knowing timing, needs the time of searching at least 5ms to detect the position of PSS.

SSS be by two length be 31 m sequence d (2k) and the sequence that is interwoven of d (2k+1), have 168 sequences.Figure 12 shows and adjust SSS on carrier wave.As shown in figure 12, the same with PSS, SSS occupies six RB centered by carrier wave, each 5 the subcarrier zero setting in sequence both sides.Unlike, the SSS sequence being positioned at subframe SF#0 and subframe SF#5 is different.

$d\left(2k\right)=\left\{\begin{array}{c}{s}_0^{m_0}\left(k\right)c_0\left(k\right),\mathrm{in\; subframe}0\\ s_0^{m_0}\left(k\right)c_0\left(k\right),\mathrm{in\; subframe}5\end{array}\right.,0\≤k\≤30$

$d(2k+1)=\left\{\begin{array}{c}{s}_1^{m_1}\left(k\right)c_1\left(k\right)z_1^{m_0}\left(k\right),\mathrm{in\; subframe}0\\ s_0^{m_0}\left(k\right)c_1\left(k\right)z_1^{m_1}\left(k\right),\mathrm{in\; subframe}5\end{array}\right.,0\≤k\≤30$

The concrete generating mode of sequence, see 3GPP 36.211, does not repeat here.

SSS detection mode normally detects based on code sequences match at frequency domain.In addition, when CP (cyclic prefix) type the unknown, may need to utilize SSS to carry out the type of blind Detecting CP.

In initial network access or during switching, terminal is carried out synchronizing symbol and is detected and obtain timing information, to set up the synchronous of between base station time and frequency.When terminal obtains after timed message, the yield value of AGC unit can according to frame structure, with an integer subframe or whole frame for interval adjusts.And when terminal not yet obtains timing information, measurement and the adjustment of AGC can not be that unit adjusts according to character boundary, this uses different gains by causing in synchronizing symbol.If such adjustment occurs in the middle of synchronizing symbol, such as, occur in PSS as shown in figure 13, or occur in as shown in figure 14 in SSS, may cause using the amplifier gain that difference is very large in PSS or SSS, this will cause the decline of synchronizing symbol detection accuracy.On the other hand, due to the independence between signal, the conversion interval of the upward signal of such as TDD system, downstream signal and uplink and downlink signals is all independently.Use another type signal based on the determined amplifier gain of certain type signal, signal may be caused to be reversed amplification, reduce the quality that subsequent synchronisation detects.As shown in figure 15, due to the unknown to signal load, or the unknown to up-downgoing, the yield value obtained from upward signal may be used to downstream signal, and the yield value in like manner obtained based on the signal in protection interval may be used in downstream signal.Protection only has noise signal in interval, and intensity is very low, and the yield value obtained like this can be very high, and when downstream signal is stronger, the downstream signal power continued can be caused significantly to promote, as shown in arrow upwards in Figure 15.Particularly when AGC adjustment cycle hour, the intensity of PSS signal may be caused and before it, intensity of downstream signal has very large difference.This difference will affect the detection of PSS and catching of frame synchronization.

Summary of the invention

Give hereinafter about brief overview of the present invention, to provide about the basic comprehension in some of the present invention.Should be appreciated that this general introduction is not summarize about exhaustive of the present invention.It is not that intention determines key of the present invention or pith, and nor is it intended to limit the scope of the present invention.Its object is only provide some concept in simplified form, in this, as the preorder in greater detail discussed after a while.

In view of above-mentioned problems of the prior art, the synchronizing symbol checkout gear provided according to embodiments of the invention and method, based on the difference between the current AGC gain obtained from AGC unit and predeterminated target gain compensate AD convert after AGC gain on the signal of down-sampling change, to obtain amplitude sampled signal comparatively stably.For the signal through gain compensation, utilize each the regular window centered by each sampling point of signal to carry out normalization to each sampling point respectively, make signal steady further.Then, synchronously detect with normalized signal.

According to embodiments of the invention, provide a kind of method detecting synchronizing symbol in a tdd system from the signal that automatic growth control AGC unit exports, described signal converts through AD in AGC unit, described method comprises: based on the difference between the current AGC gain obtained from described AGC unit and predeterminated target gain, compensate the AGC gain change on the signal that obtains after down-sampling again of signal after AD conversion, to obtain the stable sampled signal of amplitude; For each sampling point of the sampled signal compensated, the statistical value of all sampling points in the regular window centered by this sampling point is utilized to carry out normalization to this sampling point, to obtain normalized signal; And carry out synchronizing symbol detection for normalized signal, to determine position and the type of synchronizing symbol in normalized signal.

According to a further aspect in the invention, provide a kind of device detecting synchronizing symbol in a tdd system from the signal that automatic growth control AGC unit exports, described signal converts through AD in AGC unit, described device comprises: compensating unit, the AGC gain being configured to compensate on signal that the signal after AD converts obtains again after down-sampling based on the difference between the current AGC gain obtained from described AGC unit and predeterminated target gain changes, to obtain the stable sampled signal of amplitude; Pretreatment unit, is configured to, for each sampling point of the sampled signal compensated, utilize the statistical value of all sampling points in the corresponding regular window centered by this sampling point to carry out normalization to this sampling point, to obtain normalized signal; And synchronizing symbol detecting unit, be configured to carry out synchronizing symbol detection for normalized signal, to determine position and the type of synchronizing symbol in described normalized signal.

According to other side of the present invention, additionally provide corresponding computer program code, computer-readable recording medium and computer program.

According to the present invention, by carrying out preliminary treatment to the signal carried out after automatic gain adjustment, can the significantly fluctuation of signal amplitude that brings of step-down amplifier Gain tuning, ensure that the quality of subsequent synchronisation symbol detection.

By below in conjunction with the detailed description of accompanying drawing to most preferred embodiment of the present invention, these and other advantage of the present invention will be more obvious.

Accompanying drawing explanation

The present invention can be better understood by reference to hereinafter given by reference to the accompanying drawings description, wherein employs same or analogous Reference numeral in all of the figs to represent identical or similar parts.Described accompanying drawing comprises in this manual together with detailed description below and forms the part of this specification, and is used for illustrating the preferred embodiments of the present invention further and explaining principle and advantage of the present invention.In the accompanying drawings:

Fig. 1 illustrates the general flow chart detecting the method for synchronizing symbol the signal for exporting from AGC unit in a tdd system according to an embodiment of the invention;

Fig. 2 shows the allocation plan of AGC unit according to an embodiment of the invention;

Fig. 3 shows an object lesson of the process of step S110 shown in Fig. 1;

Fig. 4 shows an object lesson of the process of step S120 shown in Fig. 1;

Fig. 5 shows an object lesson of the process of step S426 shown in Fig. 4;

Fig. 6 shows and the AGC gain change in PSS symbol has been carried out to preliminary treatment and do not carried out pretreated signal to detect the PSS relevant peaks obtained comparison diagram by PSS;

Fig. 7 shows the device detecting synchronizing symbol the signal for exporting from AGC unit in a tdd system according to an embodiment of the invention;

Fig. 8 shows an object lesson of compensating unit 710 shown in Fig. 7;

Fig. 9 shows an object lesson of pretreatment unit 720 shown in Fig. 7;

Figure 10 shows the frame assumption diagram in TDD-LTE system;

Figure 11 shows the PSS modulation figure in TDD-LTE system;

Figure 12 shows the SSS modulation figure in TDD-LTE system;

Figure 13 shows the AGC gain change in PSS signal;

Figure 14 shows the AGC gain change in SSS signal;

Figure 15 shows wherein AGC gain change and causes the situation of signal power variations; And

Figure 16 shows the block diagram of the example arrangement that wherein can realize according to the method for the embodiment of the present invention and/or the all-purpose computer of device.

Embodiment

To be described one exemplary embodiment of the present invention by reference to the accompanying drawings hereinafter.For clarity and conciseness, all features of actual execution mode are not described in the description.But, should understand, must make a lot specific to the decision of execution mode in the process of any this practical embodiments of exploitation, to realize the objectives of developer, such as, meet those restrictive conditions relevant to system and business, and these restrictive conditions may change to some extent along with the difference of execution mode.In addition, although will also be appreciated that development is likely very complicated and time-consuming, concerning the those skilled in the art having benefited from present disclosure, this development is only routine task.

At this, also it should be noted is that, in order to avoid the present invention fuzzy because of unnecessary details, illustrate only in the accompanying drawings with according to the closely-related apparatus structure of the solution of the present invention and/or treatment step, and eliminate other details little with relation of the present invention.

Fig. 1 illustrates the general flow chart detecting the method for synchronizing symbol the signal for exporting from AGC unit in a tdd system according to an embodiment of the invention.

As shown in Figure 1, receiving after the signal of down-sampling, the AGC gain come on compensating signal based on the difference between the current AGC gain of AGC unit and predeterminated target gain in step S110 place changes, to obtain the stable sampled signal of amplitude; In step S120, for each sampling point of the sampled signal r compensated, the statistical value of all sampling points in the corresponding regular window centered by this sampling point is utilized to carry out normalization to this sampling point, to obtain normalized signal; And in step S130, for normalized signal r _normcarry out synchronizing symbol detection, to determine described normalized signal r _normthe position of middle synchronizing symbol and type.

It is pointed out that the signal through down-sampling that step S110 place is mentioned be actually carry out down-sampling for the signal exported from automatic growth control (AGC) unit after the signal that obtains.Fig. 2 shows the allocation plan of AGC unit according to an embodiment of the invention.

As shown in Figure 2, AGC unit is such as made up of variable gain amplifier (VGA) 210, modulus (AD) transducer 220, automatic gain maker 230 and digital-to-analogue (DA) transducer 240.The analog signal received carries out signal amplification through VGA 210, and the gain of wherein amplifying is determined by the output of automatic gain maker 230, and the signal after amplification enters AD converter 220 and becomes digital signal r (t).Digital signal r (t) after quantification is exported by as output signal.On the other hand, digital signal r (t) after quantification also enters automatic gain maker 230, and yield value G (n) (also referred to as current gain) that should use tried to achieve by automatic gain maker 230 according to the intensity of signal r (t).Current gain G (n), except being provided to VGA 230, is also exported to the compensating unit 710 shown in Fig. 7.The computational methods of current gain G (n) can be such as: utilize equation (1) below to try to achieve measurement time t _measureaverage power P (the t of interior signal r (t) _i), utilize equation (2) below to try to achieve average power P (t _i) logarithm value and target power P _targetbetween difference DELTA G, and utilize equation (3) below to obtain current gain value G (n) from previous yield value G (n-1).

$P\left(t_i\right)=\frac{1}{N_{\mathrm{measure}}}\underset{i=0}{\overset{N_{\mathrm{measure}}-1}{\mathrm{\Σ}}}{\left|r(t_i+i)\right|}^2...\left(1\right)$

ΔG＝P _target-10log ₁₀(P(t _i)) ...(2)

G(n)＝G(n-1)+ΔG ...(3)

Wherein t _ithe time started of measuring, N _measureit is measurement time t _measureinterior number of samples, and equation (4) below can be utilized to calculate target power P _target.

P _target＝P _{ADC_Max}10log ₁₀(2×(2 ^Nbit-1) ²)-P _{M arg in}[dB] ...(4)

Wherein P _{aDC_Max}=10log ₁₀(2 × (2 ^nbit-1) ²), Nbit is the bit number of digital to analog converter (ADC).P _{m arg in}the allowance considering the factors such as the peak-to-average force ratio of signal and channel variation, desirable 9 ~ P _{aDC_Max}/ 2dB.

Output signal r (t) (time-domain signal) such as carries out low-pass filtering by low pass filter LPF, with by the frequency information filtering except bandwidth shared by synchronizing symbol.Except this low-pass filtering process, other processing mode obviously can also be adopted to carry out filtering unwanted frequency information.Therefore, this low-pass filtering process is not shown in the accompanying drawings.Then, signal after filtering can be imported into independent downsampling unit and carry out down-sampling, to obtain down-sampled signal r _dS.Because synchronizing symbol only occupies six RB at carrier frequency center, consider the implementation complexity reducing subsequent cell, therefore need base band sampling rate down-sampling.As an example, the base band sampling rate of corresponding 30.72MHz, the filter that uses passband to be 1.4MHz also uses the down-sampling of 16 times.In addition, downsampling unit also can in integrated pretreatment unit 720 shown in Figure 7.

Then, based on current AGC gain G (n) and the predeterminated target gain G of AGC unit _targetn the difference between () compensates down-sampled signal r _dSon AGC gain change.Thus signal power is adjusted in certain limit, to compensate the synchronism loss of energy caused because prosign inside adopts different AGC gain.Fig. 3 shows an object lesson S310 of step S110 shown in Fig. 1.

As shown in Figure 3, first, in step S312, the yield value of the renewal in a period of time of AGC unit is averaged, to generate target gain G _target(n).Such as, equation (5) is utilized to calculate target gain G _targetn (), is wherein averaged the yield value of the nearest N number of renewal received from AGC unit.

$G_{t\arg \mathrm{et}}\left(n\right)=\frac{1}{N}\underset{i=n-N}{\overset{n}{\mathrm{\Σ}}}G\left(i\right)...\left(5\right)$

N can select AGC update times in 5ms.Depend on AGC Measuring Time, AGC update cycle etc., N value may be different, preferably, and N >=4.In addition, the corresponding time period can not be 5ms, and when representing that the coherence time of wireless channel similarity then lengthens this time period much larger than during 5ms, coherence time then shortens this time period much smaller than during 5ms.

Next, in step S314, based on current AGC gain G (n) and target gain G _targetn the difference of () determines compensating factor f _b.If the gain of AGC represents with linear value, then compensating factor f _bfor the ratio G of target gain and current AGC gain _target(n)/G (n).

If the gain of AGC represents by logarithm value, then compensating factor f _bfor

Then, in step S316, utilize compensating factor f _bto down-sampled signal r _dSaGC gain compensate.Particularly, down-sampled signal r _dSbe multiplied by compensating factor f _b, to obtain the stable sampled signal r of amplitude.

Here, although carried out AGC gain compensation to sampled signal, due to VGA device, real VGA gain amplifier and the set point of automatic gain maker 230 often have deviation.Therefore, before carrying out synchronizing symbol detection, the sampled signal r to compensating is needed to carry out further preliminary treatment, to eliminate the whole impact of AGC mistuning.

Get back to Fig. 1, in step S120, for each sampling point of the sampled signal r compensated, utilize the statistical value of all sampling points in the corresponding regular window centered by this sampling point to carry out normalization to this sampling point, to obtain normalized signal.Fig. 4 shows an object lesson S420 of step S120 shown in Fig. 1.

As shown in Figure 4, in step S422, the sampled signal r compensated is postponed W _normthe time of/2 sampling points, to obtain the signal r postponed _dL, wherein W _normbe that regular window is long, represent the number of samples in regular window.By postponing W _norm/ 2 computings realizing central window.Common hunting zone is the time of a frame.W _normadopt the N power of 2, the scope of N is preferably 3-8.

In addition, in step S424, for each sampling point of sampled signal r compensated, all sampling points in the corresponding regular window centered by this sampling point are utilized to calculate normalization factor corresponding to this sampling point.When calculating normalization factor, utilize the statistical value of all sampling points to calculate.Such as, this statistical value is the mean value based on signal amplitude.

Such as, for the Received signal strength r (m from a kth sampling point of reception antenna m in the sampled signal r compensated, k), utilize equation (6) below, normalization factor N (m, k) corresponding to Received signal strength r (m, k) adopts with Received signal strength r (m, k) the average magnitude calculation of all sampling points in the regular window centered by, regular window is long is W _norm.

$N(m,k)=\frac{1}{W_{\mathrm{norm}}}\underset{l=-W_{\mathrm{norm}}/2}{\overset{l=W_{\mathrm{norm}}/2-1}{\mathrm{\Σ}}}\left(\sqrt{{\left|\mathrm{Re}\left(r(m,k+l)\right)\right|}^2+{\left|\mathrm{Im}\left(r(m,k+l)\right)\right|}^2}\right)...\left(6\right)$

Or, equation (7) below can be utilized to calculate normalization factor N (m, k):

$N(m,k)=\frac{1}{W_{\mathrm{norm}}}\underset{l=-W_{\mathrm{norm}}/2}{\overset{i=W_{\mathrm{norm}}/2-1}{\mathrm{\Σ}}}(\mathrm{\αMax}\left(\right|\mathrm{Re}\left(r(m,k+l)\right)|,|\mathrm{Im}\left(r(m,k+l)\right)\left|\right)+\mathrm{\βMin}\left(\right|\mathrm{Re}\left(r(m,k+l)\right)|,|\mathrm{Im}\left(r(m,k+l)\right)\left|\right))...\left(7\right)$

Wherein α and β optimizes by experiment, and a kind of embodiment of optimum is α=1, β=0.5, and other value comparatively optimized also has: α=7/8, β=7/16, α=15/16, β=15/32, and α=0.96, β=0.4.In order to further simplification, also can adopt α=1, β=0, namely equation (7) is reduced to

$N(m,k)=\frac{1}{W_{\mathrm{norm}}}\underset{l=-W_{\mathrm{norm}}/2}{\overset{l=W_{\mathrm{norm}}/2-1}{\mathrm{\Σ}}}\mathrm{Max}\left(\right|\mathrm{Re}\left(r(m,k+l)\right)|,|\mathrm{Im}\left(r(m,k+l)\right)\left|\right)$

For each sampling point of the sampled signal r compensated, preferably, adopt the equal long W of regular window _norm.

Next, in step S426, utilize normalization factor to the signal r postponed _dLcorresponding sampling point carry out normalization, to obtain normalized signal r _norm.Fig. 5 shows an object lesson S526 of step S426 shown in Fig. 4.

As shown in Figure 5, utilize the highest-order bit detector 510 pairs of normalization factor N (m, k) to carry out the highest-order bit detection, find the position n of normalization factor N (m, k) the highest-order bit, with 2 ⁿreplace normalization factor N (m, k), namely single-bit is similar to normalization factor N (m, k), then utilizes bit shifter 520 to the signal r postponed _dLthe Received signal strength r of a kth sampling point _dL(m, k) carries out n-bit shifting function to obtain the normalized signal r of a kth sampling point _norm(m, k).For the signal r postponed _dLall sampling points utilize respective normalization factor to carry out normalization operations successively, thus obtain normalized signal r _morm.In addition, in order to improve the approximation quality of normalization factor N (m, k), can be similar to many bits, namely using A*2 ⁿapproximate normalization factor N (m, k), A are the parameters relevant with approximate bit number.The Received signal strength r of a kth sampling point is first multiplied by with 1/A _dLthe normalized signal r that n-bit displacement obtains a kth sampling point is carried out again after (m, k) _norm(m, k).Another advantage of this regular implementation method prevents the problem except zero in normalization process.

Get back to Fig. 1, next, in step S130, for normalized signal r _normcarry out synchronizing symbol detection, to determine described normalized signal r _normthe position of middle synchronizing symbol and type.

Such as, the signal r after normalization process _normoutput to PSS detecting unit and carry out PSS detection, to detect position and the type of PSS.Then, the signal r after normalization process _normbe output SSS detecting unit with the testing result of PSS detecting unit and carry out SSS detection, to detect position and the type of SSS.

Fig. 6 gives and the AGC gain change in PSS symbol has been carried out to preliminary treatment and do not carried out pretreated signal to detect the PSS relevant peaks obtained comparison diagram by PSS, and AGC gain wherein differs 6dB.As can be seen from Figure 6, the PSS relevant peaks of not carrying out pretreated signal is not obvious, and correlation peak is very low to the ratio (peak-to-average force ratio) of relevant average.After employing pretreatment unit according to the present invention carries out preliminary treatment to signal, the PSS relevant peaks obtained is very outstanding, and peak-to-average force ratio is very high, thus significantly improves the quality of PSS detection.

Although below composition graphs 3 and 4 is described according to the concrete processing procedure of the step S110 shown in Fig. 1 of the embodiment of the present invention and S120 respectively, the present invention is not limited thereto.

Can find out, according to technical scheme of the present invention can significantly the signal amplitude fluctuations brought of step-down amplifier Gain tuning on the impact of synchronizing symbol testing process.Specifically, such as can reduce AGC by the technological means of first carrying out AGC gain compensation to the signal after carrying out automatic gain adjustment and adjust the signal amplitude fluctuations brought, then reduce AGC further by normalized technological means and adjust the signal amplitude fluctuations brought, to ensure the quality of subsequent synchronisation symbol detection.

Except detecting the method for synchronizing symbol the signal for exporting from automatic growth control AGC unit in a tdd system described above, according to embodiments of the invention, also accordingly provide the device detecting synchronizing symbol corresponding with the described method signal for exporting from automatic growth control AGC unit in a tdd system.

Fig. 7 shows according to an embodiment of the invention for detecting the device 700 of synchronizing symbol in a tdd system from the signal of automatic growth control AGC unit output.

As shown in Figure 7, the device detecting synchronizing symbol in a tdd system from the signal that automatic growth control AGC unit exports according to the embodiment of the present invention comprises: compensating unit 710, be configured to based on the difference between the current AGC gain obtained from described AGC unit and predeterminated target gain compensate AD convert after through the signal r of down-sampling _dSon AGC gain change, to obtain the stable sampled signal r of amplitude; Pretreatment unit 720, is configured to, for each sampling point of the sampled signal r compensated, utilize the statistical value of all sampling points in the corresponding regular window centered by this sampling point to carry out normalization to this sampling point, to obtain normalized signal r _norm; And synchronizing symbol detecting unit 730, be configured to for normalized signal r _normcarry out synchronizing symbol detection, to determine described normalized signal r _normthe position of middle synchronizing symbol and type.

Fig. 8 shows an object lesson 810 of compensating unit 710 shown in Fig. 7.

As shown in Figure 8, compensating unit 810 comprises: target gain generating unit 814, is configured to the gain of the renewal in the special time period of AGC unit to be averaged, to generate predeterminated target gain; Compensating factor determining means 812, is configured to the difference determination compensating factor based on current AGC gain and described predeterminated target gain; And compensate execution unit 816, be configured to utilize compensating factor to compensate the AGC gain change on the signal of down-sampling.

Particularly, target gain generating unit 814 is averaged the yield value of the renewal in a period of time from AGC unit, to generate target gain G _target(n).The target gain G that the compensating factor determining means 812 of such as controller generates with target gain generating unit 814 based on the current AGC gain G (n) from AGC unit _targetn the difference of () determines compensating factor f _b.If the gain of AGC represents with linear value, then compensating factor f _bfor the ratio G of target gain and current AGC gain _target(n)/G (n).

If the gain of AGC represents by logarithm value, then compensating factor f _bfor

The compensation execution unit 816 of such as multiplier is the down-sampled signal r of input _dSbe multiplied by the determined compensating factor f of compensating factor determining means 812 _b, to obtain the stable sampled signal r of amplitude.

Fig. 9 shows an object lesson 920 of pretreatment unit 720 shown in Fig. 7.

As shown in Figure 9, pretreatment unit 920 comprises: delay unit 922, is configured to the sampled signal r compensated to postpone W _normthe time of/2 sampling points, to obtain the signal r postponed _dL, wherein W _normthe sampling point quantity in corresponding regular window; Normalization factor calculating unit 924, is configured to each sampling point of sampled signal r for compensating, and utilizes all sampling points in the corresponding regular window centered by this sampling point to calculate normalization factor corresponding to this sampling point; And regular execution unit 926, the normalization factor being configured to utilize normalization factor calculating unit 924 to calculate is to the signal r of the delay that delay unit 922 exports _dLcorresponding sampling point carry out normalization, to obtain normalized signal r _norm.

Device 700 shown in above-mentioned Fig. 7 and the included unit 810,920 shown in unit 710-720 and Fig. 8,9 thereof can be configured to perform above with reference to the various operations described by Fig. 3 and Fig. 4.About the further details of these operations, with reference to each embodiment described above, embodiment and example, can be not described in detail here, to make specification succinct.

[01] such as can be realized by the mode of software, hardware, firmware or their combination in any according to the synchronizing symbol checkout gear of the various embodiments described above of the present invention.When this synchronizing symbol checkout gear takes hardware mode to realize, the patterns such as integrated circuit (IC) chip, card of surfing Internet, USB-bar can be taked.

Easy understand, the synchronizing symbol checkout gear according to the various embodiments described above of the present invention can realize as discrete functional entity, also can integrate with corresponding terminal equipment and realize.Therefore, the terminal equipment of this synchronizing symbol checkout gear is equipped with also should to covered within protection scope of the present invention.This terminal equipment such as can comprise mobile phone, palmtop computer, kneetop computer, data card, USB rod, receiver on-board, intelligent appliance, intelligent electric meter etc.

Be described in detail by block diagram, flow chart and/or embodiment above, illustrated the different execution modes of devices in accordance with embodiments of the present invention and/or method.When these block diagrams, flow chart and/or embodiment comprise one or more function and/or operation, it will be obvious to those skilled in the art that each function in these block diagrams, flow chart and/or embodiment and/or operation can by various hardware, software, firmware or in fact they combination in any and implement individually and/or jointly.In one embodiment, several parts of the theme described in this specification realize by application-specific IC (ASIC), field programmable gate array (FPGA), digital signal processor (DSP) or other integrated forms.But, those skilled in the art will recognize that, some aspects of the execution mode described in this specification can whole or in part in integrated circuits with the form of the one or more computer programs run on one or more computers (such as, form with the one or more computer programs run in one or more computer system), with the form of the one or more programs run on the one or more processors (such as, form with the one or more programs run on one or more microprocessor), with the form of firmware, or implement equivalently with the form of their combination in any in fact, and, according to content disclosed in this specification, be designed for circuit of the present disclosure and/or the code write for software of the present disclosure and/or firmware is completely within the limit of power of those skilled in the art.

Such as, said apparatus 700 and all modules, unit, subelement can be configured by the mode of software, firmware, hardware or its combination in any.When being realized by software or firmware, to the computer (all-purpose computer 1600 such as shown in Figure 16) with specialized hardware structure, the program forming this software can be installed from storage medium or network, this computer, when being provided with various program, can perform various function.

Figure 16 shows and can be used for implementing the schematic block diagram according to the computer of the method and apparatus of the embodiment of the present invention.

In figure 16, CPU (CPU) 1601 performs various process according to the program stored in read-only memory (ROM) 1602 or from the program that storage area 1608 is loaded into random access memory (RAM) 1603.In RAM 1603, also store the data required when CPU1601 performs various process etc. as required.CPU 501, ROM 1602 and RAM 1603 are connected to each other via bus 1604.Input/output interface 1605 is also connected to bus 1604.

Following parts are also connected to input/output interface 1605: importation 1606 (comprising keyboard, mouse etc.), output 1607 (comprise display, such as cathode ray tube (CRT), liquid crystal display (LCD) etc., and loud speaker etc.), storage area 1608 (comprising hard disk etc.), communications portion 1609 (comprising network interface unit such as LAN card, modulator-demodulator etc.).Communications portion 1609 is via network such as internet executive communication process.As required, driver 1610 also can be connected to input/output interface 1605.Detachable media 1611 such as disk, CD, magneto optical disk, semiconductor memory etc. can be installed on driver 1610 as required, and the computer program therefrom read is installed in storage area 1608 as required.

When series of processes above-mentioned by software simulating, can from network such as internet or the program from storage medium such as detachable media 1611 installation formation software.

It will be understood by those of skill in the art that this storage medium is not limited to wherein having program stored therein shown in Figure 16, distributes the detachable media 1611 to provide program to user separately with equipment.The example of detachable media 1611 comprises disk (comprising floppy disk), CD (comprising compact disc read-only memory (CD-ROM) and digital universal disc (DVD)), magneto optical disk (comprising mini-disk (MD) (registered trade mark)) and semiconductor memory.Or hard disk that storage medium can be ROM 1602, comprise in storage area 1608 etc., wherein computer program stored, and user is distributed to together with comprising their equipment.

Therefore, the invention allows for a kind of program product storing the instruction code of machine-readable.When described instruction code is read by machine and performs, the above-mentioned various methods according to the embodiment of the present invention can be performed.Correspondingly, the above-named various storage medium for carrying this program product is also included within of the present invention disclosing.

Method and apparatus according to the present invention is not only applicable to TDD-LTE system, is equally applicable to have adoptive IMT-Advanced system, as TDD-LTE Advanced system etc. with LTE system future.

Above in the description of the specific embodiment of the invention, the feature described for a kind of execution mode and/or illustrate can use in one or more other execution mode in same or similar mode, combined with the feature in other execution mode, or substitute the feature in other execution mode.

Should emphasize, term " comprises/comprises " existence referring to feature, key element, step or assembly when using herein, but does not get rid of the existence or additional of one or more further feature, key element, step or assembly.

In addition, method of the present invention be not limited to specifications in describe time sequencing perform, also can according to other time sequencing ground, perform concurrently or independently.Therefore, the execution sequence of the method described in this specification is not construed as limiting technical scope of the present invention.

About the execution mode comprising above embodiment, following remarks is also disclosed:

Remarks 1. 1 kinds detects the device of synchronizing symbol in tdd communication system from the signal that automatic growth control AGC unit exports, described device comprises: compensating unit, be configured to based on the difference between the current AGC gain obtained from described AGC unit and predeterminated target gain compensate AD convert after AGC gain on the signal of down-sampling change, to obtain the stable sampled signal of amplitude; Pretreatment unit, is configured to, for each sampling point of the sampled signal compensated, utilize the statistical value of all sampling points in the corresponding regular window centered by this sampling point to carry out normalization to this sampling point, to obtain normalized signal; And synchronizing symbol detecting unit, be configured to carry out synchronizing symbol detection for normalized signal, to determine position and the type of synchronizing symbol in described normalized signal.

The device of remarks 2. according to remarks 1, wherein said compensating unit comprises: target gain generating unit, is configured to the gain of the renewal in the predetermined amount of time of described AGC unit to be averaged, to generate described predeterminated target gain; Compensating factor determining means, is configured to the difference determination compensating factor based on current AGC gain and described predeterminated target gain; And compensation execution unit, be configured to utilize described compensating factor to compensate described AGC gain change on the signal of down-sampling.

The device of remarks 3. according to remarks 2, wherein, described target gain generating unit is configured to utilize following formula to calculate described predeterminated target gain:

$G_{t\arg \mathrm{et}}\left(n\right)=\frac{1}{N}\underset{i=n-N}{\overset{n}{\mathrm{\Σ}}}G\left(i\right)$

Wherein N is the number of the gain of described renewal, meets the relation of N >=4, and the G (n) during i=n represents current AGC gain; Described compensating factor determining means is configured to determine described compensating factor by described predeterminated target gain and the ratio of current AGC gain or the difference of described predeterminated target gain and current AGC gain; And described compensation execution unit to be configured to the described signal times through down-sampling with described compensating factor to obtain the stable sampled signal of amplitude.

The device of remarks 4. according to any one of remarks 1-3, wherein, described pretreatment unit comprises: delay unit, is configured to the sampled signal compensated to postpone W _normthe time of/2 sampling points, to obtain the signal postponed, wherein W _normthe sampling point quantity in corresponding regular window; Normalization factor calculating unit, is configured to each sampling point of sampled signal for compensating, and utilizes all sampling points in the corresponding regular window centered by this sampling point to calculate normalization factor corresponding to this sampling point; And regular execution unit, be configured to utilize the corresponding sampling point of normalization factor to the signal postponed to carry out normalization.

The device of remarks 5. according to remarks 4, wherein, described normalization factor calculating unit is configured to each sampling point of sampled signal for compensating, and utilizes the mean value of the modulus value of all sampling points in the corresponding regular window centered by this sampling point to calculate normalization factor corresponding to this sampling point.

The device of remarks 6. according to remarks 4, wherein, described regular execution unit is configured to carry out the highest-order bit detection to normalization factor, to determine the position n of the highest-order bit, with A × 2 ⁿcarry out bit to normalization factor to be similar to, and carry out n-bit shifting function after 1/A is multiplied by the corresponding sampling point of signal postponed, wherein A be more than or equal to 1 constant.

Remarks 7. is according to described device arbitrary in remarks 1-3, and also comprise filter, the signal that this filter is configured to AGC unit exports carries out low-pass filtering, with by the frequency information filtering except synchronizing symbol.

Remarks 8. is according to described device arbitrary in remarks 1-3, and wherein, described tdd communication system is TDD-LTE system or TDD-LTE Advaned system.

Remarks 9. 1 kinds for detecting the method for synchronizing symbol in tdd communication system from the signal that automatic growth control AGC unit exports, described method comprises: based on the difference between the current AGC gain obtained from described AGC unit and predeterminated target gain, AGC gain after compensating AD conversion on the signal of down-sampling changes, to obtain the stable sampled signal of amplitude; For each sampling point of the sampled signal compensated, the statistical value of all sampling points in the corresponding regular window centered by this sampling point is utilized to carry out normalization to this sampling point, to obtain normalized signal; And carry out synchronizing symbol detection for normalized signal, to determine position and the type of synchronizing symbol in described normalized signal.

The method of remarks 10. according to remarks 9, wherein compensates AGC gain change and comprises: the gain of the renewal in the predetermined amount of time of described AGC unit is averaged, to generate described predeterminated target gain; Based on the difference determination compensating factor of current AGC gain and described predeterminated target gain; And utilize described compensating factor to compensate described AGC gain change on the signal of down-sampling.

The method of remarks 11. according to remarks 10, wherein, utilizes following formula to calculate described predeterminated target gain:

$G_{t\arg \mathrm{et}}\left(n\right)=\frac{1}{N}\underset{i=n-N}{\overset{n}{\mathrm{\Σ}}}G\left(i\right)$

Wherein N is the number of the gain of described renewal, meets the relation of N >=4, and the G (n) during i=n represents current AGC gain; Described compensating factor is determined by described predeterminated target gain and the ratio of current AGC gain or the difference of described predeterminated target gain and current AGC gain; And the described signal times through down-sampling is obtained the stable sampled signal of amplitude with described compensating factor.

The method of remarks 12. according to any one of remarks 9-11, wherein, carries out normalization and comprises: the sampled signal compensated is postponed W _normthe time of/2 sampling points, to obtain the signal postponed, wherein W _normthe sampling point quantity in corresponding regular window; For each sampling point of sampled signal compensated, all sampling points in the corresponding regular window centered by this sampling point are utilized to calculate normalization factor corresponding to this sampling point; And utilize the corresponding sampling point of normalization factor to the signal postponed to carry out normalization.

The method of remarks 13. according to remarks 12, wherein, for each sampling point of sampled signal compensated, utilizes the average modulus value of all plural sampling point in the corresponding regular window centered by this sampling point to calculate normalization factor corresponding to this sampling point.

The method of remarks 14. according to remarks 12, wherein, carries out normalization to corresponding sampling point and comprises: carry out the highest-order bit detection to normalization factor, to determine the position n of the highest-order bit, with A × 2 ⁿcarry out bit to normalization factor to be similar to, and carry out n-bit shifting function after 1/A is multiplied by the corresponding sampling point of signal postponed, wherein A be more than or equal to 1 constant.

Remarks 15., according to described method arbitrary in remarks 9-11, is also included in before compensating AGC gain change and carries out low-pass filtering to the signal that AGC unit exports, with by the frequency information filtering except synchronizing symbol.

Remarks 16. is according to described method arbitrary in remarks 9-11, and wherein, described tdd communication system is TDD-LTE system or TDD-LTE Advanced system.

Remarks 17, a kind of terminal equipment had as the device detected for the synchronizing symbol in tdd communication system as described in performing in remarks 1-8 as described in any one.

Remarks 18. 1 kinds stores the program product of the instruction code of machine-readable, when described instruction code is read by machine and performs, can perform as the method performing synchronizing symbol detection in tdd communication system in remarks 9-16 as described in any one.

Remarks 19. 1 kinds carries the storage medium of the program product as described in remarks 18.

Although above by the description of specific embodiments of the invention to invention has been disclosure, but, should be appreciated that, those skilled in the art can design various amendment of the present invention, improvement or equivalent in the spirit and scope of claims.These amendments, improvement or equivalent also should be believed to comprise in protection scope of the present invention.

Claims (10)

1. in tdd communication system, detect a device for synchronizing symbol from the signal that automatic growth control AGC unit exports, described signal is through AD conversion in AGC unit, and described device comprises:

Compensating unit, the AGC gain being configured to compensate on signal that described signal after AD converts obtains again after down-sampling based on the difference between the current AGC gain obtained from described AGC unit and predeterminated target gain changes, to obtain the stable sampled signal of amplitude;

Pretreatment unit, is configured to, for each sampling point of the sampled signal compensated, utilize the statistical value of all sampling points in the corresponding regular window centered by this sampling point to carry out normalization to this sampling point, to obtain normalized signal; And

Synchronizing symbol detecting unit, is configured to carry out synchronizing symbol detection for normalized signal, to determine position and the type of synchronizing symbol in described normalized signal.

2. device according to claim 1, wherein said compensating unit comprises:

Target gain generating unit, is configured to the gain of the renewal in the predetermined amount of time of described AGC unit to be averaged, to generate described predeterminated target gain;

Compensating factor determining means, is configured to the difference determination compensating factor based on current AGC gain and described predeterminated target gain; And

Compensate execution unit, be configured to utilize described compensating factor to compensate described AGC gain change on the signal of down-sampling.

3. device according to claim 2, wherein, described target gain generating unit is configured to utilize following formula to calculate described predeterminated target gain:

$G_{t\arg \mathrm{et}}\left(n\right)=\frac{1}{N}\underset{i=n-N}{\overset{n}{\mathrm{\Σ}}}G\left(i\right)$

Wherein N is the number of the gain of described renewal, meets the relation of N >=4, and the G (n) during i=n represents current AGC gain;

Described compensating factor determining means is configured to determine described compensating factor by described predeterminated target gain and the ratio of current AGC gain or the difference of described predeterminated target gain and current AGC gain; And

Described compensation execution unit to be configured to the described signal times through down-sampling with described compensating factor to obtain the stable sampled signal of amplitude.

4. the device according to any one of claim 1-3, wherein, described pretreatment unit comprises:

Delay unit, is configured to the sampled signal compensated to postpone W _normthe time of/2 sampling points, to obtain the signal postponed, wherein W _normthe sampling point quantity in corresponding regular window;

Normalization factor calculating unit, is configured to each sampling point of sampled signal for compensating, and utilizes all sampling points in the corresponding regular window centered by this sampling point to calculate normalization factor corresponding to this sampling point; And

Normalization execution unit, is configured to utilize the corresponding sampling point of normalization factor to the signal postponed to carry out normalization.

5. device according to claim 4, wherein, described normalization factor calculating unit is configured to each sampling point of sampled signal for compensating, and utilizes the mean value of the modulus value of all sampling points in the corresponding regular window centered by this sampling point to calculate normalization factor corresponding to this sampling point.

6. device according to claim 4, wherein, described regular execution unit is configured to carry out the highest-order bit detection to normalization factor, to determine the position n of the highest-order bit, with A × 2 ⁿcarry out bit to normalization factor to be similar to, and carry out n-bit shifting function after 1/A is multiplied by the corresponding sampling point of signal postponed, wherein A be more than or equal to 1 constant.

7. according to described device arbitrary in claim 1-3, also comprise filter, the signal that this filter is configured to AGC unit exports carries out low-pass filtering, with by the frequency information filtering except synchronizing symbol.

8., according to described device arbitrary in claim 1-3, wherein, described tdd communication system is TDD-LTE system or TDD-LTE Advaned system.

9., for detecting a method for synchronizing symbol in tdd communication system from the signal that automatic growth control AGC unit exports, described signal is through AD conversion in AGC unit, and described method comprises:

Based on the difference between the current AGC gain obtained from described AGC unit and predeterminated target gain, compensate the AGC gain change on the described signal that obtains after down-sampling again of signal after AD conversion, to obtain the stable sampled signal of amplitude;

For each sampling point of the sampled signal compensated, the statistical value of all sampling points in the corresponding regular window centered by this sampling point is utilized to carry out normalization to this sampling point, to obtain normalized signal; And

Synchronizing symbol detection is carried out, to determine position and the type of synchronizing symbol in described normalized signal for normalized signal.

10. method according to claim 9, wherein compensates AGC gain change and comprises:

The gain of the renewal in the predetermined amount of time of described AGC unit is averaged, to generate described predeterminated target gain;

Based on the difference determination compensating factor of current AGC gain and described predeterminated target gain; And

Described compensating factor is utilized to compensate described AGC gain change on the signal of down-sampling.