CN102347925A - Synchronization symbol detection method and apparatus thereof - Google Patents

Abstract

The invention provides a synchronization symbol detection method for a signal 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 to (Time Division Duplex-Long Term Evolution in TDD system especially TDD-LTE; Time division duplex-Long Term Evolution) from receive signal, detects synchronizing symbol (Synchronization symbol, method and apparatus SS) in the system.

Background technology

In the wireless communication system, because the fading effect of wireless channel will cause receiving on the signal amplitude fluctuating widely.In order to guarantee the precision after the signal quantization, the terminal need use automatic gain control (Auto gain control) unit to come the dynamically variation of tracking signal usually.(Analog digital converter, working range ADC) when the reception signal is more weak, improve Amplifier Gain, the gain of step-down amplifier when the reception signal is too high according to analog digital converter.The measurement of AGC and adjustment need be carried out based on the frame structure that receives signal, bring additional distortion can not for the reception signal with the adjustment that guarantees amplifier gain.The adjustment of AGC has very big influence for the quality of the synchronous detecting of carrying out in the synchronizing process between terminal and base station.

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

In the LTE of TDD mode (TDD-LTE) system, receive signal and realize synchronously and the obtaining of cell synchronizing sign pattern through relevant with the time domain of local synchronizing symbol.Therefore, in application, after receiving signal, need from receive signal, detect synchronizing symbol.In the TDD-LTE system, there are seven kinds of frame structure configurations as shown in table 1.With " D " sign descending sub frame, " U " identifies sub-frame of uplink in the table 1, and " S " identifies special subframe.Each subframe lengths is 1ms, and the slot that is 0.5ms by two length forms.As shown in table 1, and main synchronizing symbol (Primary synchronization symbol, PSS) being arranged in the subframe sequence number is 1 and 6 subframe, (Secondary synchronization symbol, SSS) be arranged in the subframe sequence number is 0 and 5 subframe to auxilliary synchronizing symbol.Figure 10 has provided the tdd frame structure of half subframe, and wherein subframe SF#1 (sequence number is 1 subframe) is a special subframe, and subframe SF#1 is made up of descending time slot DwPTS, up-downgoing conversion interval GP and ascending time slot UpPTS.Among 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 0 subframe).Cell searching utilizes the detection to these two synchronizing symbols to obtain frame timing and sub-district ID.

Table 1

PSS is a length of 62 Zadoff-Chu sequence

(k = 0,1, ..., 61), a total of 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 25,29, one of 34}.Figure 11 shows and on carrier wave, adjusts PSS.Shown in Figure 11, the sequence around the center of the DC sub-carrier 31, the corresponding DC subcarrier

set to zero.The same zero setting of five number of sub-carrier on sequence both sides.Totally 72 number of sub-carrier are corresponding to six RB (resource block, Resource Block) at center.PSS sequence at subframe SF#1 and subframe SF#6 is identical.

The detection method based on matched filtering is usually adopted in the detection of PSS, is not knowing under the situation regularly, and the time of 5ms at least of need searching for is detected the position of PSS.

SSS is to be the sequence that 31 m sequence d (2k) and d (2k+1) are interwoven by two length, has 168 sequences.Figure 12 shows and on carrier wave, adjusts SSS.As shown in figure 12, the same with PSS, SSS occupies six RB that carrier wave is the center, each the 5 number of sub-carrier zero setting of sequence both sides.Different is that the SSS sequence that is positioned at subframe SF#0 and subframe SF#5 is different.

$d\left(2k\right)=\left\{\begin{array}{c}{s}_0^{m_0}\left(k\right)c_0\left(k\right),\mathrm{in\; subframe}0\\ s_0^{m_0}\left(k\right)c_0\left(k\right),\mathrm{in\; <figure-callout\; id="0"\; label="subframe"\; filenames="HSA00000215936600041.png,HSA00000215936600061.png"\; state="\{\{state\}\}">subframe</figure-callout>}5\end{array}\right.,0\&le;k\&le;30$

$d(2k+1)=\left\{\begin{array}{c}{s}_1^{m_1}\left(k\right)c_1\left(k\right)z_1^{m_0}\left(k\right),\mathrm{in\; subframe}0\\ s_0^{m_0}\left(k\right)c_1\left(k\right)z_1^{m_1}\left(k\right),\mathrm{in\; <figure-callout\; id="0"\; label="subframe"\; filenames="HSA00000215936600041.png,HSA00000215936600061.png"\; state="\{\{state\}\}">subframe</figure-callout>}5\end{array}\right.,0\&le;k\&le;30$

The concrete generating mode of sequence is not given unnecessary details referring to 3GPP 36.211 here.

The SSS detection mode normally detects based on the sign indicating number sequences match at frequency domain.In addition, under CP (cyclic prefix) type condition of unknown, possibly utilize SSS to come the type of blind Detecting CP.

Insert or between transfer period at initial network, the terminal is carried out synchronizing symbol and is detected and obtain timing information, so as to set up and the base station between time and frequency synchronous.After the terminal obtained timed message, the yield value of AGC unit can serve as to adjust at interval with integer sub-frame or whole frame according to frame structure.And when the terminal did not obtain timing information as yet, the measurement of AGC and adjustment can not be that unit adjusts according to character boundary, and this will cause using in the synchronizing symbol different gains.If such adjustment occurs in the middle of the synchronizing symbol; Such as, occur in as shown in figure 13 among the PSS, perhaps occur among the SSS as shown in figure 14; Possibly cause using the very big amplifier gain of difference in PSS or the SSS, this will cause the decline of synchronizing symbol detection accuracy.On the other hand, because the independence between the signal, all be independently such as the conversion interval of upward signal, downstream signal and the uplink and downlink signals of TDD system.Another type signal is used in determined amplifier gain based on certain type signal, may cause signal to be reversed amplification, reduces the quality that subsequent synchronisation detects.As shown in figure 15, owing to the unknown to signal load, perhaps to the unknown of up-downgoing, the yield value of obtaining from upward signal possibly be used to the downstream signal, and in like manner the yield value of obtaining based on the signal in the protection at interval possibly used in the downstream signal.Have only noise signal in the protection at interval, intensity is very low, and the yield value of obtaining like this can be very high, and when descending signal was strong, the downstream signal power that can cause continuing significantly promoted, shown in the arrow that makes progress among Figure 15.Particularly, possibly cause the intensity of PSS signal and the intensity of its front downstream signal that very big difference is arranged when AGC adjustment cycle hour.This difference will influence the detection of PSS and catching of frame synchronization.

Summary of the invention

Provided hereinafter about brief overview of the present invention, so that the basic comprehension about some aspect of the present invention is provided.Should be appreciated that this general introduction is not about exhaustive general introduction of the present invention.It is not that intention is confirmed key of the present invention or pith, neither be intended to limit scope of the present invention.Its purpose only is to provide some notion with the form of simplifying, with this as the preorder in greater detail of argumentation after a while.

In view of the problem that exists in the above-mentioned prior art; According to synchronizing symbol checkout gear and the method that embodiments of the invention provided; Difference between gaining with predeterminated target based on the current AGC gain that obtains from the AGC unit compensates after the AD conversion through the AGC change in gain on the signal of down-sampling, to obtain amplitude sampled signal comparatively stably.For through the signal of gain compensation, utilizing each sampling point with signal is that each regular window at center carries out normalization to each sampling point respectively, makes signal further steady.Then, carry out synchronous detecting with normalized signal.

According to embodiments of the invention; A kind of method that in the TDD system, from the signal of automatic gain control AGC unit output, detects synchronizing symbol is provided; Said method comprises: based on the difference between current AGC gain that obtains from said AGC unit and the predeterminated target gain; Compensate after the AD conversion through the AGC change in gain on the said signal of down-sampling, to obtain amplitude sampled signal stably; For each sampling point of sampled signal of compensation, utilizing with this sampling point is that the statistical value of all sampling points in the regular window at center carries out normalization to this sampling point, to obtain normalized signal; And carry out synchronizing symbol to normalized signal and detect, to confirm the position and the type of synchronizing symbol in the normalized signal.

According to a further aspect in the invention; A kind of device that in the TDD system, from the signal of automatic gain control AGC unit output, detects synchronizing symbol is provided; Said device comprises: compensating unit; Difference between being configured to gain with predeterminated target based on the current AGC gain that obtains from said AGC unit compensates after the AD conversion through the AGC change in gain on the said signal of down-sampling, to obtain amplitude sampled signal stably; Pretreatment unit is configured to each sampling point of sampled signal for compensation, and utilizing with this sampling point is that the statistical value of all sampling points in the corresponding regular window at center carries out normalization to this sampling point, to obtain normalized signal; And the synchronizing symbol detecting unit, be configured to carry out synchronizing symbol and detect, to confirm the position and the type of synchronizing symbol in the said normalized signal to normalized signal.

According to others of the present invention, corresponding computer programs code, computer-readable recording medium and computer program are provided also.

According to the present invention, through carrying out preliminary treatment to carrying out the adjusted signal of automatic gain, significantly the fluctuation of the signal amplitude of being brought is adjusted in the step-down amplifier gain, has guaranteed the quality of subsequent synchronisation symbol detection.

Through 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.

Description of drawings

The present invention can wherein use same or analogous Reference numeral to represent identical or similar parts in institute's drawings attached through with reference to hereinafter combining the given description of accompanying drawing to be better understood.Said accompanying drawing comprises in this manual and forms the part of this specification together with following detailed description, and is used for further illustrating the preferred embodiments of the present invention and explains principle and advantage of the present invention.In the accompanying drawings:

Fig. 1 illustrates the general flow chart that is used for detecting from the signal of AGC unit output in the TDD system method of synchronizing symbol 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 processing of the S110 of step shown in Fig. 1;

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

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

Fig. 6 shows for the AGC change in gain in the PSS symbol and has carried out preliminary treatment and do not carried out pretreated signal detects the PSS relevant peaks that obtains through PSS comparison diagram;

Fig. 7 shows the device that is used for detecting from the signal of AGC unit output in the TDD system synchronizing symbol according to an embodiment of the invention;

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

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

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

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

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

Figure 13 shows the AGC change in gain in the PSS signal;

Figure 14 shows the AGC change in gain in the SSS signal;

Figure 15 shows the situation that AGC change in gain wherein causes signal power variations; And

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

Embodiment

To combine accompanying drawing that one exemplary embodiment of the present invention is described hereinafter.In order to know and for simplicity, in specification, not describe all characteristics of actual execution mode.Yet; Should understand; In the process of any this practical embodiments of exploitation, must make a lot of decisions specific to execution mode; So that realize developer's objectives; For example; Meet and system and professional those relevant restrictive conditions, and these restrictive conditions may change along with the difference of execution mode to some extent.In addition, might be very complicated and time-consuming though will also be appreciated that development, concerning the those skilled in the art that have benefited from present disclosure, this development only is customary task.

At this; What also need illustrate a bit is; For fear of having blured the present invention, only show in the accompanying drawings and closely-related apparatus structure of scheme according to the present invention and/or treatment step, and omitted other details little with relation of the present invention because of unnecessary details.

Fig. 1 illustrates the general flow chart that is used for detecting from the signal of AGC unit output in the TDD system method of synchronizing symbol according to an embodiment of the invention.

As shown in Figure 1, receiving, coming the AGC change in gain on the compensating signal at step S110 place based on the current AGC gain of AGC unit and the difference between the predeterminated target gain, to obtain amplitude sampled signal stably through behind the signal of down-sampling; At step S120, for each sampling point of sampled signal r of compensation, utilizing with this sampling point is that the statistical value of all sampling points in the corresponding regular window at center carries out normalization to this sampling point, to obtain normalized signal; And at step S130, to normalized signal r _NormCarry out synchronizing symbol and detect, to confirm said normalized signal r _NormThe position and the type of middle synchronizing symbol.

It is pointed out that the signal through down-sampling that step S110 place mentions is actually to the signal from automatic gain control (AGC) unit output carries out the signal that obtains after the down-sampling.Fig. 2 shows the allocation plan of AGC unit according to an embodiment of the invention.

As shown in Figure 2, the AGC unit for example is 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 that receives is carried out signal through VGA 210 and is amplified, and wherein the gain of Fang Daing is by the output decision of automatic gain maker 230, and the signal after the amplification gets into AD converter 220 and becomes digital signal r (t).Digital signal r after the quantification (t) is used as the output of output signal.On the other hand, the digital signal r after the quantification (t) also gets into automatic gain maker 230, and automatic gain maker 230 is tried to achieve the yield value G (n) (being also referred to as current gain) that should use according to the intensity of signal r (t).Current gain G (n) also is exported to the compensating unit 710 shown in Fig. 7 except being provided for VGA 230.The computational methods of current gain G (n) for example can be: the equality (1) below utilizing is tried to achieve measurement time t _MeasureAverage power P (the t of interior signal r (t) _i), the equality (2) below utilizing is tried to achieve average power P (t _i) logarithm value and target power P _TargetBetween difference DELTA G, and the equality (3) below utilizing obtains current gain value G (n) from yield value G (n-1) last time.

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

ΔG＝P _target-10log ₁₀(P(t _i)) ...(2)

G(n)＝G(n-1)+ΔG ...(3)

T wherein _iBe the time started of measuring, N _MeasureIt is measurement time t _MeasureInterior number of samples, and can utilize following equality (4) to calculate target power P _Target

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

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

Output signal r (t) (time-domain signal) for example carries out low-pass filtering through low pass filter LPF, with will be except that the frequency information filtering the shared bandwidth of synchronizing symbol.Except this low-pass filtering process, obviously can also adopt other processing mode to come filtering unwanted frequency information.Therefore, this low-pass filtering process is not shown in the accompanying drawings.Then, the signal of process filtering can be imported into independent downsampling unit and carry out down-sampling, to obtain down-sampled signal r _DSBecause synchronizing symbol only occupies six RB at carrier frequency center, consider to reduce the implementation complexity of follow-up unit, therefore need be with baseband sampling speed down-sampling.As an example, the baseband sampling speed of corresponding 30.72MHz uses passband as the filter of 1.4MHz and use 16 times down-sampling.In addition, downsampling unit also can integrated pretreatment unit shown in Figure 7 720 in.

Then, based on the current AGC gain G (n) of AGC unit and predeterminated target gain G _Target(n) difference between compensates down-sampled signal r _DSOn the AGC change in gain.Thereby signal power is adjusted in the certain limit, to compensate the synchronism loss of energy that adopts different AGC gains to cause owing to prosign is inner.Fig. 3 shows the object lesson S310 of the S110 of step shown in Fig. 1.

As shown in Figure 3, at 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).For example, utilize equality (5) to calculate target gain G _Target(n), wherein N that receives from the AGC unit recently yield value that upgrades averaged.

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

N can select AGC update times in the 5ms for use.Depend on AGC Measuring Time, AGC update cycle etc., the N value maybe be different, preferably, and N >=4.In addition, the time corresponding section can not be 5ms, and then extend during much larger than 5ms should the time period when coherence time of expression wireless channel similarity, and then shorten during much smaller than 5ms coherence time should the time period.

Next, at step S314, based on current AGC gain G (n) and target gain G _Target(n) difference is confirmed compensating factor f _bIf the gain of AGC representes with linear value, compensating factor f then _bRatio G for target gain and current AGC gain _Target(n)/G (n).

If the gain of AGC representes with logarithm value, compensating factor f then _bFor

Then, at step S316, utilize compensating factor f _bTo down-sampled signal r _DSAGC gain compensate.Particularly, down-sampled signal r _DSMultiply by compensating factor f _b, to obtain amplitude sampled signal r stably.

Here, though sampled signal has been carried out the AGC gain compensation, because the VGA device, the real VGA gain amplifier and the set point of automatic gain maker 230 often have deviation.Therefore, before carrying out the synchronizing symbol detection, need carry out further preliminary treatment, to eliminate the whole influence of AGC mistuning to the sampled signal r of compensation.

Get back to Fig. 1, at step S120, for each sampling point of sampled signal r of compensation, utilizing with this sampling point is that the statistical value of all sampling points in the corresponding regular window at center carries out normalization to this sampling point, to obtain normalized signal.Fig. 4 shows the object lesson S420 of the S120 of step shown in Fig. 1.

As shown in Figure 4, at step S422, the sampled signal r of compensation is postponed W _NormThe time of/2 sampling points is with the signal r that obtains postponing _DL, W wherein _NormBe that regular window is long, represent the number of samples in the regular window.Through postponing W _Norm/ 2 computings that realize central window.Common hunting zone is the time of a frame.W _NormAdopt 2 N power, the scope of N is 3-8 preferably.

In addition, at step S424, to each sampling point of sampled signal r of compensation, utilizing with this sampling point is that all sampling points in the corresponding regular window at center calculate the normalization factor corresponding to this sampling point.When calculating normalization factor, utilize the statistical value of all sampling points to calculate.For example, this statistical value is based on the mean value of signal amplitude.

For example; To among the sampled signal r of compensation from the reception signal r (m of k the sampling point of reception antenna m; K); Equality (6) below utilizing; Corresponding to receive signal r (m, (m k) adopts to receive signal r (m normalization factor N k); K) be the average mould value calculating of interior all sampling points of regular window at center, regular window is long to be W _Norm

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

Perhaps, can utilize following equality (7) calculate normalization factor N (m, k):

$N(m,k)=\frac{1}{W_{\mathrm{norm}}}\underset{l=-W_{\mathrm{norm}}/2}{\overset{i=W_{\mathrm{norm}}/2-1}{\mathrm{\&Sigma;}}}(\mathrm{\&alpha;Max}\left(\right|\mathrm{Re}\left(r(m,k+l)\right)|,|\mathrm{Im}\left(r(m,k+l)\right)\left|\right)+\mathrm{\&beta;Min}\left(\right|\mathrm{Re}\left(r(m,k+l)\right)|,|\mathrm{Im}\left(r(m,k+l)\right)\left|\right))...\left(7\right)$

Wherein α and β are through optimum experimental, and a kind of embodiment of optimum is α=1, β=0.5, and other value of comparatively optimizing also has: α=7/8, β=7/16, α=15/16, β=15/32, and α=0.96, β=0.4.For further simplification, also can adopt α=1, β=0, promptly equality (7) is reduced to

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

For each sampling point of the sampled signal r that compensates, preferably, adopt the long W of regular window that equates _Norm

Next, at step S426, utilize the signal r of normalization factor to postponing _DLCorresponding sampling point carry out normalization, to obtain normalized signal r _NormFig. 5 shows the object lesson S526 of the S426 of step shown in Fig. 4.

As shown in Figure 5, (m k) carries out the highest-order bit and detects, and (m, k) the position n of the highest-order bit is with 2 to seek normalization factor N to utilize 510 couples of normalization factor N of the highest-order bit detector ⁿ(m, k), promptly (m k), utilizes the signal r of 520 pairs of delays of bit shift unit to the approximate normalization factor N of single-bit then to replace normalization factor N _DLThe reception signal r of k sampling point _DL(m k) carries out the normalized signal r that the shifting function of n bit obtains k sampling point _Norm(m, k).To the signal r that postpones _DLAll sampling point utilizations normalization factor separately carry out normalization operation successively, thereby obtain normalized signal r _MormIn addition, (m, approximation quality k) can use many bits approximate, promptly use A*2 in order to improve normalization factor N ⁿ(m, k), A is the parameter relevant with being similar to bit number to approximate normalization factor N.Multiply by the reception signal r of k sampling point earlier with 1/A _DL(m carries out the n bit after k) again and is shifted and obtains the normalized signal r of k sampling point _Norm(m, k).Another advantage of this regular implementation method is to have prevented in normalization process, to remove zero problem.

Get back to Fig. 1, next, at step S130, to normalized signal r _NormCarry out synchronizing symbol and detect, to confirm said normalized signal r _NormThe position and the type of middle synchronizing symbol.

For example, through the signal r after the normalization process _NormOutput to the PSS detecting unit and carry out the PSS detection, to detect position and the type of PSS.Then, through the signal r after the normalization process _NormExported the SSS detecting unit with the testing result of PSS detecting unit and carried out the SSS detection, to detect position and the type of SSS.

Fig. 6 has provided for the AGC change in gain in the PSS symbol and has carried out preliminary treatment and do not carry out pretreated signal and detect the comparison diagram of the PSS relevant peaks obtain through 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 with the ratio (peak-to-average force ratio) of relevant average.After employing pretreatment unit according to the present invention carried out preliminary treatment to signal, resulting PSS relevant peaks was very outstanding, and peak-to-average force ratio is very high, thereby had significantly improved the quality that PSS detects.

Though below combine Fig. 3 and 4 pairs of concrete processing procedures according to step S110 shown in Fig. 1 of the embodiment of the invention and S120 to be described respectively, the present invention is not limited thereto.

Can find out, according to technical scheme of the present invention significantly the signal amplitude fluctuations brought of step-down amplifier gain adjustment to the influence of synchronizing symbol testing process.Specifically; For example can be through at first reducing the signal amplitude fluctuations that the AGC adjustment is brought to carrying out the technological means that the adjusted signal of automatic gain carries out the AGC gain compensation; Come further to reduce the signal amplitude fluctuations that the AGC adjustment is brought through normalized technological means then, to guarantee the quality of subsequent synchronisation symbol detection.

Except described above being used for detects the method for synchronizing symbol from the signal of automatic gain control AGC unit output in the TDD system; According to embodiments of the invention, the device that be used in TDD system from the signal of automatic gain control AGC unit output detect synchronizing symbol corresponding with said method is provided correspondingly also.

Fig. 7 shows the device 700 that is used for detecting from the signal of automatic gain control AGC unit output in the TDD system synchronizing symbol according to an embodiment of the invention.

As shown in Figure 7; The device that in the TDD system, from the signal of automatic gain control AGC unit output, detects synchronizing symbol according to the embodiment of the invention comprises: compensating unit 710, the difference between being configured to gain with predeterminated target based on the current AGC gain that obtains from said AGC unit compensate after the AD conversion signal r through down-sampling _DSOn the AGC change in gain, to obtain amplitude sampled signal r stably; Pretreatment unit 720 is configured to each sampling point of sampled signal r for compensation, and utilizing with this sampling point is that the statistical value of all sampling points in the corresponding regular window at center carries out normalization to this sampling point, to obtain normalized signal r _NormAnd synchronizing symbol detecting unit 730, be configured to normalized signal r _NormCarry out synchronizing symbol and detect, to confirm said normalized signal r _NormThe position and the type of middle synchronizing symbol.

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

As shown in Figure 8, compensating unit 810 comprises: target gain generates parts 814, is configured to the gain of the renewal in the special time period of AGC unit is averaged, to generate the predeterminated target gain; Compensating factor is confirmed parts 812, is configured to confirm compensating factor based on the current AGC gain and the difference of said predeterminated target gain; And compensation execution unit 816, be configured to utilize compensating factor to compensating through the AGC change in gain on the signal of down-sampling.

Particularly, target gain generates parts 814 yield value from the renewal in a period of time of AGC unit is averaged, to generate target gain G _Target(n).Confirm that such as the compensating factor of controller parts 812 generate the target gain G that parts 814 are generated based on the current AGC gain G (n) from the AGC unit with target gain _Target(n) difference is confirmed compensating factor f _bIf the gain of AGC representes with linear value, compensating factor f then _bRatio G for target gain and current AGC gain _Target(n)/G (n).

If the gain of AGC representes with logarithm value, compensating factor f then _bFor

816 down-sampled signal r that import of compensation execution unit such as multiplier _DSMultiply by compensating factor and confirm parts 812 determined compensating factor f _b, to obtain amplitude sampled signal r stably.

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

As shown in Figure 9, pretreatment unit 920 comprises: delay unit 922 is configured to the sampled signal r of compensation is postponed W _NormThe time of/2 sampling points is with the signal r that obtains postponing _DL, W wherein _NormBe the sampling point quantity in the corresponding regular window; Normalization factor calculating unit 924 is configured to each sampling point of sampled signal r to compensation, and utilizing with this sampling point is that all sampling points in the corresponding regular window at center calculate the normalization factor corresponding to this sampling point; And regular execution unit 926, be configured to utilize normalization factor that normalization factor calculating unit 924 calculates signal r to the delay of delay unit 922 outputs _DLCorresponding sampling point carry out normalization, to obtain normalized signal r _Norm

Device 700 shown in above-mentioned Fig. 7 and included each unit 710-720 and Fig. 8, the unit shown in 9 810,920 thereof can be configured to carry out top with reference to Fig. 3 and the described various operations of Fig. 4.About the further details of these operations, can be not described in detail here, so that specification is succinct with reference to each embodiment, embodiment and the instance of above description.

[01] the synchronizing symbol checkout gear of above-mentioned each embodiment for example can be realized through the mode of software, hardware, firmware or their combination in any according to the present invention.When this synchronizing symbol checkout gear takes hardware mode to realize, can take appearance attitudes such as integrated circuit (IC) chip, card of surfing Internet, USB-bar.

Understand easily, the synchronizing symbol checkout gear of above-mentioned each embodiment can be used as discrete functional entity and realizes according to the present invention, also can integrate with corresponding terminal device and realize.Therefore, be equipped with the terminal equipment of this synchronizing symbol checkout gear also should covered within protection scope of the present invention.This terminal equipment for example can comprise mobile phone, palmtop computer, kneetop computer, data card, USB rod, vehicle-mounted receiver, intelligent appliance, intelligent electric meter or the like.

Describe in detail through 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 functions and/or operation; It will be obvious to those skilled in the art that among these block diagrams, flow chart and/or the embodiment each function and/or operation can through various hardware, software, firmware or in fact they combination in any and individually and/or enforcement jointly.In one embodiment, the several sections of the theme of describing in this specification can pass through application-specific IC (ASIC), field programmable gate array (FPGA), digital signal processor (DSP) or other integrated form realizations.Yet; Those skilled in the art will recognize that; Some aspects of the execution mode of describing in this specification can be whole or in part in integrated circuit with the form of one or more computer programs of on one or more computers, moving (for example; Form with one or more computer programs of on one or more computer systems, moving); With the form of one or more programs of on one or more processors, moving (for example; Form with one or more programs of on one or more microprocessors, moving); Form with firmware; Or implement equivalently with the form of their combination in any in fact; And; According to disclosed content in this specification, being designed for circuit of the present disclosure and/or writing the code that is used for software of the present disclosure and/or firmware is fully within those skilled in the art's limit of power.

For example, said apparatus 700 can be configured through the mode of software, firmware, hardware or its combination in any with each composition module, unit, subelement.Under situation about realizing through software or firmware; Can the program that constitute this software be installed to the computer with specialized hardware structure (all-purpose computer 1600 for example shown in Figure 16) from storage medium or network; This computer can be carried out various functions when various program is installed.

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

In Figure 16, CPU (CPU) 1601 carries out various processing according to program stored among 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 data required when CPU1601 carries out various processing or the like as required.CPU 501, ROM 1602 and RAM 1603 are connected to each other via bus 1604.Input/output interface 1605 also is connected to bus 1604.

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

Realizing through software under the situation of above-mentioned series of processes, can from network for example the internet or from storage medium for example detachable media 1611 program that constitutes softwares is installed.

It will be understood by those of skill in the art that this storage medium is not limited to shown in Figure 16 wherein having program stored therein, distribute so that the detachable media 1611 of program to be provided to the user with equipment with being separated.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.Perhaps, storage medium can be hard disk that comprises in ROM 1602, the storage area 1608 or the like, computer program stored wherein, and be distributed to the user with the equipment that comprises them.

Therefore, the invention allows for a kind of program product that stores the instruction code of machine-readable.When said instruction code is read and carried out by machine, can carry out above-mentioned the whole bag of tricks according to the embodiment of the invention.Correspondingly, the above-named various storage mediums that are used for carrying this program product are also included within of the present invention open.

The method according to this invention is not only applicable to the TDD-LTE system with device, is equally applicable to following and LTE system and has adoptive IMT-Advanced system, like TDD-LTE Advanced system etc.

In the above in the description to the specific embodiment of the invention; Characteristic to a kind of execution mode is described and/or illustrated can be used in one or more other execution mode with identical or similar mode; Combined with the characteristic in other execution mode, or substitute the characteristic in other execution mode.

Should stress that term " comprises/comprise " existence that when this paper uses, refers to characteristic, key element, step or assembly, but not get rid of the existence of one or more further feature, key element, step or assembly or additional.

In addition, the time sequencing of describing during method of the present invention is not limited to is to specifications carried out, also can according to other time sequencing ground, carry out concurrently or independently.Therefore, the execution sequence of the method for describing in this specification does not constitute restriction to technical scope of the present invention.

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

1. 1 kinds of devices that in the TDD communication system, from the signal of automatic gain control AGC unit output, detect synchronizing symbol of remarks; Said device comprises: compensating unit; Difference between being configured to gain with predeterminated target based on the current AGC gain that obtains from said AGC unit compensates after the AD conversion through the AGC change in gain on the signal of down-sampling, to obtain amplitude sampled signal stably; Pretreatment unit is configured to each sampling point of sampled signal for compensation, and utilizing with this sampling point is that the statistical value of all sampling points in the corresponding regular window at center carries out normalization to this sampling point, to obtain normalized signal; And the synchronizing symbol detecting unit, be configured to carry out synchronizing symbol and detect, to confirm the position and the type of synchronizing symbol in the said normalized signal to normalized signal.

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

Remarks 3. is according to remarks 2 described devices, and wherein, said target gain generates component configuration and becomes to utilize following formula to calculate said predeterminated target gain:

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

Wherein N is the number of the gain of said renewal, satisfies the relation of N >=4, and the current AGC gain of the expression of the G (n) during i=n; Said compensating factor confirms that component configuration becomes the ratio or the gain of said predeterminated target that gain through said predeterminated target gain and current AGC to confirm said compensating factor with the difference that current AGC gains; And said compensation execution unit is configured to said signal times through down-sampling is obtained amplitude sampled signal stably with said compensating factor.

Remarks 4. is according to each described device among the remarks 1-3, and wherein, said pretreatment unit comprises: delay unit is configured to the sampled signal of compensation is postponed W _NormThe time of/2 sampling points is with the signal that obtains postponing, wherein W _NormBe the sampling point quantity in the corresponding regular window; The normalization factor calculating unit is configured to each sampling point of sampled signal to compensation, and utilizing with this sampling point is that all sampling points in the corresponding regular window at center calculate the normalization factor corresponding to this sampling point; And regular execution unit, be configured to utilize normalization factor that the corresponding sampling point of the signal that postpones is carried out normalization.

Remarks 5. is according to remarks 4 described devices; Wherein, Said normalization factor calculating unit is configured to each sampling point of sampled signal to compensation, and utilizing with this sampling point is that the mean value of the mould value of all sampling points in the corresponding regular window at center calculates the normalization factor corresponding to this sampling point.

Remarks 6. is according to remarks 4 described devices, and wherein, said regular execution unit is configured to that normalization factor is carried out the highest-order bit and detects, to confirm the position n of the highest-order bit, with A * 2 ⁿIt is approximate that normalization factor is carried out bit, and carry out the shifting function of n bit after the corresponding sampling point of the signal that postpones multiply by 1/A, and wherein A is the constant more than or equal to 1.

Remarks 7. also comprises filter according to arbitrary described device among the remarks 1-3, and this filter is configured to the signal of AGC unit output is carried out low-pass filtering, with frequency information filtering that will be except that synchronizing symbol.

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

9. 1 kinds of methods that are used for from the signal of automatic gain control AGC unit output, detecting synchronizing symbol of remarks in the TDD communication system; Said method comprises: based on the difference between current AGC gain that obtains from said AGC unit and the predeterminated target gain; Compensate after the AD conversion through the AGC change in gain on the signal of down-sampling, to obtain amplitude sampled signal stably; For each sampling point of sampled signal of compensation, utilizing with this sampling point is that the statistical value of all sampling points in the corresponding regular window at center carries out normalization to this sampling point, to obtain normalized signal; And carry out synchronizing symbol to normalized signal and detect, to confirm the position and the type of synchronizing symbol in the said normalized signal.

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

Remarks 11. wherein, utilizes following formula to calculate said predeterminated target gain according to remarks 10 described methods:

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

Wherein N is the number of the gain of said renewal, satisfies the relation of N >=4, and the current AGC gain of the expression of the G (n) during i=n; Confirm said compensating factor through said predeterminated target gain and the ratio or the gain of said predeterminated target of current AGC gain with the difference of current AGC gain; And said signal times through down-sampling obtained amplitude sampled signal stably with said compensating factor.

Remarks 12. wherein, carries out normalization and comprises according to each described method among the remarks 9-11: the sampled signal of compensation is postponed W _NormThe time of/2 sampling points is with the signal that obtains postponing, wherein W _NormBe the sampling point quantity in the corresponding regular window; To each sampling point of sampled signal of compensation, utilizing with this sampling point is that all sampling points in the corresponding regular window at center calculate the normalization factor corresponding to this sampling point; And utilize normalization factor that the corresponding sampling point of the signal that postpones is carried out normalization.

Remarks 13. is according to remarks 12 described methods, and wherein, to each sampling point of the sampled signal of compensation, utilizing with this sampling point is that the average mould value of all the plural sampling points in the corresponding regular window at center is calculated the normalization factor corresponding to this sampling point.

Remarks 14. wherein, carries out normalization to corresponding sampling point and comprises according to remarks 12 described methods: normalization factor is carried out the highest-order bit detect, to confirm the position n of the highest-order bit, with A * 2 ⁿIt is approximate that normalization factor is carried out bit, and carry out the shifting function of n bit after the corresponding sampling point of the signal that postpones multiply by 1/A, and wherein A is the constant more than or equal to 1.

Remarks 15. is according to arbitrary described method among the remarks 9-11, is included in also that the signal to the output of AGC unit carries out low-pass filtering before the compensation AGC change in gain, with frequency information filtering that will be except that synchronizing symbol.

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

Remarks 17, a kind of have as among the remarks 1-8 any one described be used for carrying out as described in the terminal equipment of the device that detects of the synchronizing symbol of TDD communication system.

18. 1 kinds of program products that store the instruction code of machine-readable of remarks when said instruction code is read and carried out by machine, can be carried out like any one described method of in the TDD communication system, carrying out the synchronizing symbol detection among the remarks 9-16.

19. 1 kinds of storage mediums that carry like remarks 18 described program products of remarks.

Although the present invention is disclosed above through description to specific embodiment of the present invention; But; Should be appreciated that those skilled in the art can design various modifications of the present invention, improve or equivalent in the spirit and scope of accompanying claims.These modifications, improvement or equivalent also should be believed to comprise in protection scope of the present invention.

Claims (10)

1. in the TDD communication system, control the device that detects synchronizing symbol the signal of exporting the AGC unit from automatic gain for one kind, said device comprises:

Compensating unit, the difference between being configured to gain with predeterminated target based on the current AGC gain that obtains from said AGC unit compensate after the AD conversion through the AGC change in gain on the signal of down-sampling, to obtain amplitude sampled signal stably;

Pretreatment unit is configured to each sampling point of sampled signal for compensation, and utilizing with this sampling point is that the statistical value of all sampling points in the corresponding regular window at center carries out normalization to this sampling point, to obtain normalized signal; And

The synchronizing symbol detecting unit is configured to carry out synchronizing symbol to normalized signal and detects, to confirm the position and the type of synchronizing symbol in the said normalized signal.

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

Target gain generates parts, is configured to the gain of the renewal in the predetermined amount of time of said AGC unit is averaged, to generate said predeterminated target gain;

Compensating factor is confirmed parts, is configured to confirm compensating factor based on the current AGC gain and the difference of said predeterminated target gain; And

The compensation execution unit is configured to utilize said compensating factor to compensate through the AGC change in gain on the signal of down-sampling said.

3. device according to claim 2, wherein, said target gain generates component configuration and becomes to utilize following formula to calculate said predeterminated target gain:

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

Wherein N is the number of the gain of said renewal, satisfies the relation of N >=4, and the current AGC gain of the expression of the G (n) during i=n;

Said compensating factor confirms that component configuration becomes the ratio or the gain of said predeterminated target that gain through said predeterminated target gain and current AGC to confirm said compensating factor with the difference that current AGC gains; And

Said compensation execution unit is configured to said signal times through down-sampling is obtained amplitude sampled signal stably with said compensating factor.

4. according to each described device among the claim 1-3, wherein, said pretreatment unit comprises:

Delay unit is configured to the sampled signal of compensation is postponed W _NormThe time of/2 sampling points is with the signal that obtains postponing, wherein W _NormBe the sampling point quantity in the corresponding regular window;

The normalization factor calculating unit is configured to each sampling point of sampled signal to compensation, and utilizing with this sampling point is that all sampling points in the corresponding regular window at center calculate the normalization factor corresponding to this sampling point; And

The normalization execution unit is configured to utilize normalization factor that the corresponding sampling point of the signal that postpones is carried out normalization.

5. device according to claim 4; Wherein, Said normalization factor calculating unit is configured to each sampling point of sampled signal to compensation, and utilizing with this sampling point is that the mean value of the mould value of all sampling points in the corresponding regular window at center calculates the normalization factor corresponding to this sampling point.

6. device according to claim 4, wherein, said regular execution unit is configured to that normalization factor is carried out the highest-order bit and detects, to confirm the position n of the highest-order bit, with A * 2 ⁿIt is approximate that normalization factor is carried out bit, and carry out the shifting function of n bit after the corresponding sampling point of the signal that postpones multiply by 1/A, and wherein A is the constant more than or equal to 1.

7. according to arbitrary described device among the claim 1-3, also comprise filter, this filter is configured to the signal of AGC unit output is carried out low-pass filtering, with frequency information filtering that will be except that synchronizing symbol.

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

9. one kind is used for controlling the method that detects synchronizing symbol the signal of exporting the AGC unit in the TDD communication system from automatic gain, and said method comprises:

Difference between gaining with predeterminated target based on the current AGC gain that obtains from said AGC unit compensates after the AD conversion through the AGC change in gain on the signal of down-sampling, to obtain amplitude sampled signal stably;

For each sampling point of sampled signal of compensation, utilizing with this sampling point is that the statistical value of all sampling points in the corresponding regular window at center carries out normalization to this sampling point, to obtain normalized signal; And

Carry out synchronizing symbol to normalized signal and detect, to confirm the position and the type of synchronizing symbol in the said normalized signal.

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

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

Confirm compensating factor based on the current AGC gain and the difference of said predeterminated target gain; And

Utilize said compensating factor to compensate through the AGC change in gain on the signal of down-sampling to said.

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