CN102413543B - Initial AGC (automatic gain control) method and equipment of LTE (long term evolution) system - Google Patents

Abstract

The invention discloses an initial AGC (automatic gain control) method and equipment of an LTE (long term evolution) system. The method comprises the following steps of: measuring and sending an average power of receiving signals according to a first preset time interval; calculating the bias between the average power and a preset target power to obtain a gain error; smoothing the gain error according to a first smoothing factor to obtain a smoothing gain error; updating the current AGC gain value by use of the smoothing gain error; and converting the updated AGC gain value to obtain an AGC control word, and sending the AGC control word according to a second preset time interval. In the invention, the quick measurement and quick adjustment of the initial AGC can be realized through the processes, and finally the aims of improving the signal quality for cell search and improving the sensitivity of the cell search are achieved.

Description

A kind of initial AGC method and apparatus of LTE system

Technical field

The present invention relates to communication technical field, in particular, relate to the method and apparatus of the initial AGC (Automatic Gain Control, automatic gain control) of a kind of LTE (Long Term Evolution system, Long Term Evolution) system

Background technology

Current for the development of the communication technology, start to carry out transition to the 4G epoch from the 3G epoch, and LTE (Long Term Evolution system, Long Term Evolution) system is thought 4G wireless communication system widely.Wherein, the physical layer of LTE adopts OFDM (Orthogonal Frequency Division Multiplexing, OFDM) technology.After LTE terminal equipment start, carry out the AGC process of terminal equipment, for controlling the power that receives signal, anti-stop signal is saturated, reduces the quantizing noise in each signal processing, thereby improves the signal to noise ratio in receiver, its course of work as shown in Figure 1, comprises the steps:

Step S11, carry out Cell searching, mainly be to obtain community ID (IDentity, community number), the information such as Timing Synchronization information, dual-mode (FDD/TDD), CP (Cyclic Prefix, Cyclic Prefix) pattern (normal CP/extended CP); Step S12, obtains system information, is mainly to receive MIB (master information block, Master Information Block) and SIB (System Information block, system information block) information; Step S13, carries out access at random, mainly refers to terminal access community, and obtains the process of RNTI (Radio Network Temporary Identifier) and more system information; Step S14, carries out normal business.In above-mentioned four steps, divide according to the course of work of AGC (Automatic Gain Control, automatic gain control), step S11 is the initial AGC stage, step S12, step S13, step S14 are AGC tracking phase.Due in above-mentioned AGC process, frame timing information and the frame structure information that cannot know in the initial AGC stage (comprise dual-mode, CP pattern, up-downgoing proportioning, known at AGC tracking phase, therefore,, in whole AGC process, only have to carry out to AGC tracking phase just can get accurately, representative time domain or frequency-region signal carry out AGC measurement and AGC and control and adjust.

Due to, the control quality in initial AGC stage directly has influence on sensitivity and the search time of terminal receiver Cell searching, and then also directly has influence on performance and user's experience of terminal.Therefore, in the prior art, general employing slow tune mode as shown in Figure 2 solves the problem of initial AGC, the power of reception signal is for a long time averaged to (power measurement unit 205), as be greater than 10ms, obtain the measurement power of current reception signal, contrast with the target reference power of default reception signal again, draw gain error (gain error computing unit 206), thereby then gain error is converted into AGC and adjusts control word and feed back to radio-frequency devices and adjust the working gain (AGC control word generation unit 207) of LNA/VGA constant power control device.In accompanying drawing 2,201 is LNA/VGA unit, and 202 is AD conversion unit, and 203 is low-pass filter unit, and 204 is FFT (Fast Fourier Transformation, fast Fourier transform) unit.

But in existing TD-LTE (TD-LTE is the technology of the LTE of TDD (Time Division Duplexing, time division duplex) version) system, each radio frames contains ascending-descending subframes, as shown in table 1.

Table 1:

Due to, in the initial AGC stage, terminal equipment, always in receiving mode, that is to say that the signal in the sub-frame of uplink time can be received and process by terminal equipment.Now, while utilizing initial AGC solution of the prior art to carry out received signal power measurement, the received signal power in the sub-frame of uplink time all can be added up interior.And in this process, if the signal power receiving in sub-frame of uplink is very large, there is other-end carrying out up transmission as neighbouring, can cause AGC that the data of the descending sub frame of Cell searching use (are contained to PSS (Primary Synchronization Signal, main synchronizing symbol)/SSS (Secondary Synchronization Signal, auxiliary synchronizing symbol)) be adjusted to very little; If or the signal power receiving in sub-frame of uplink is very little, can cause like this AGC that the data of the descending sub frame of Cell searching use (containing PSS/SSS) are adjusted to very large, until saturated.

And there are the problems referred to above in the time adopting prior art to solve initial AGC, finally can cause directly reducing the sensitivity for signal quality and the reduction Cell searching of Cell searching.

Summary of the invention

In view of this, the invention provides the method and apparatus of a kind of initial AGC of LTE system, to overcome prior art at terminal equipment during always in receiving mode, cannot be accurately to received signal power measure, thereby cause reducing Cell searching signal quality and community and search the problem of plain sensitivity.

For achieving the above object, the invention provides following technical scheme:

A method of the initial automatic gain control AGC of Long Term Evolution LTE system, comprising:

Receive the average power of signal by the first Preset Time interval measurement and transmission;

Calculate the deviation between described average power and goal-selling power, obtain gain error;

According to the first smoothing factor, described gain error is carried out smoothly, obtaining level and smooth gain error;

Utilize described level and smooth gain error to upgrade current automatic gain control AGC yield value;

AGC yield value after conversion is upgraded, obtains AGC control word and sends by the second Preset Time interval.

Preferably, the described process by the average power of the first Preset Time interval measurement and transmission reception signal comprises:

The average power P of the time domain sampling point in described the first Preset Time interval that calculating sampling arrives;

The range value of described time domain sampling point is: S _i=I _i+ j*Q _i, wherein, S _ifor complex signal, be divided into I, Q two-way, i=0,1 ..., N-1, N is counting of the described time domain sampling point that grabs; Described average power $P=\underset{i=1}{\overset{N-1}{\mathrm{\Σ}}}(I_i^2+Q_i^2)/N;$

Change described average power P into dB value, send by described the first Preset Time interval.

Preferably, the described process by the average power of the first Preset Time interval measurement and transmission reception signal comprises:

The time domain sampling point of sampling in described the first Preset Time interval, the power of node-by-node algorithm time domain sampling point described in each;

According to the second smoothing factor, utilize continuously the power of time domain sampling point described in each is carried out smoothly, obtaining average power P;

Wherein, β is the second smoothing factor, and the value of described β comprises 1/128, P ₀for initial average power value is 0, and every level and smooth through a sampling point, P ₀be updated to the value of P; The range value of described time domain sampling point is: S _i=I _i+ j*Q _i, wherein, S _ifor complex signal, be divided into I, Q two-way, i=0,1 ..., N-1, N is counting of the described time domain sampling point that grabs,

Change described average power P into dB value, send by described the first Preset Time interval.

Preferably, the points N of described time domain sampling point comprises all number of samples in the first Preset Time interval;

Or, the part number of samples continuously or in the described first Preset Time interval of choosing at interval, the span of described part number of samples is: 2 power side.

Preferably, according to default smoothing factor, described gain error is carried out smoothly, the process that obtains level and smooth gain error comprises:

Obtain described the first smoothing factor, and receive described gain error;

Based on smooth manner, obtain described level and smooth gain error;

Wherein, G _errorfor described gain error, for described level and smooth gain error, α is the first smoothing factor, and the span of described α is 0.1～0.5.

Preferably, the process of utilizing described level and smooth gain error to upgrade current AGC yield value comprises:

Obtain the gain error after carrying out smoothly to described gain error, and current AGC yield value;

The initial value of described current AGC yield value is 0, and the process of upgrading described current AGC yield value is;

In the time that described level and smooth gain error is greater than zero, reduce described current AGC yield value, the value reducing is level and smooth gain error;

In the time that described level and smooth gain error is less than zero, increase described current AGC yield value, the absolute value that the value increasing is level and smooth gain error;

In the time that described level and smooth gain error equals zero, maintain described current AGC yield value constant.

Preferably, the value at described very first time interval comprises the time span of an orthogonal frequency division multiplex OFDM symbol;

The value at described the second Preset Time interval comprises the time span of an OFDM symbol.

An equipment of the initial automatic gain control AGC of Long Term Evolution LTE system, comprising:

Signal power measurement unit, for receive the average power of signal by the first Preset Time interval measurement, and sends described average power by described the first Preset Time interval;

Gain error computing unit, for calculating the deviation between described average power and goal-selling power, obtains gain error;

Gain error smooth unit, for carrying out smoothly, obtaining level and smooth gain error to described gain error according to the first smoothing factor;

AGC control word generation unit, for utilizing described level and smooth gain error to upgrade current automatic gain control AGC yield value, and changes the AGC yield value after upgrading, and generates the AGC control word that described AGC yield value is corresponding and sends by the second Preset Time interval;

AGC control unit, be used for comprising to described signal power measurement unit and export the first Preset Time interval, to described gain error computing unit output goal-selling power, export the first smoothing factor to described gain error smooth unit, and send the second Preset Time interval of AGC control word to described AGC control word generation unit output.

Preferably, described signal power measurement unit comprises:

Sampling unit, for the time domain sampling point of sampling in described the first Preset Time interval;

Computing unit, for calculating the average power of described time domain sampling point;

Converting unit, for changing described average power into dB value, sends by described the first Preset Time interval.

Preferably, described signal power measurement unit comprises:

Sampling unit, for the time domain sampling point of sampling in described the first Preset Time interval;

Smooth unit, for the power of node-by-node algorithm time domain sampling point described in each, and carries out smoothly, obtaining average power to the power of time domain sampling point described in each according to the second smoothing factor continuously; Described the second smoothing factor is exported by described AGC control unit;

Converting unit, for changing described average power into dB value, sends by described the first Preset Time interval.

Known via above-mentioned technical scheme, compared with prior art, the invention discloses the method and apparatus of a kind of initial AGC of LTE system.By the time domain sampling point in sampling time interval, carry out the calculating of relevant power measurement and gain error and level and smooth, finally generate and send AGC control word by the time interval, and make the data dimension of the descending sub frame that Cell searching uses be held in normal condition according to this AGC control word.By the mode of Quick Measurement and quick adjustment, final realization improved the signal quality that is used for Cell searching, and improves the object of Cell searching sensitivity.

Brief description of the drawings

In order to be illustrated more clearly in the embodiment of the present invention or technical scheme of the prior art, to the accompanying drawing of required use in embodiment or description of the Prior Art be briefly described below, apparently, accompanying drawing in the following describes is only embodiments of the invention, for those of ordinary skill in the art, do not paying under the prerequisite of creative work, other accompanying drawing can also be provided according to the accompanying drawing providing.

Fig. 1 is the workflow diagram of LTE terminal equipment in prior art;

Fig. 2 is the device schematic diagram of corresponding initial AGC mechanism in prior art;

Fig. 3 is the method flow diagram of the initial AGC of the disclosed a kind of LTE system of the embodiment of the present invention;

Fig. 4 is the method flow diagram of the initial AGC of the disclosed a kind of LTE system of the embodiment of the present invention one;

Fig. 5 is the method flow diagram of the initial AGC of the disclosed a kind of LTE system of the embodiment of the present invention two;

Fig. 6 is the equipment schematic diagram of the initial AGC of the disclosed a kind of LTE system of the embodiment of the present invention;

Fig. 7 is the equipment schematic diagram of the initial AGC of the disclosed another kind of LTE system of the embodiment of the present invention.

Embodiment

For quote and know for the purpose of, the explanation of the technical term hereinafter using, write a Chinese character in simplified form or abridge and be summarized as follows:

LTE:Long Term Evolution system, long evolving system;

AGC:Automatic Gain Control, automatic gain control;

OFDM:Orthogonal Frequency Division Multiplexing, OFDM.

Below in conjunction with the accompanying drawing in the embodiment of the present invention, the technical scheme in the embodiment of the present invention is clearly and completely described, obviously, described embodiment is only the present invention's part embodiment, instead of whole embodiment.Based on the embodiment in the present invention, those of ordinary skill in the art, not making the every other embodiment obtaining under creative work prerequisite, belong to the scope of protection of the invention.

From background technology, at initial AGC stage terminal equipment always in receiving mode, adopt the slow tune mode of prior art to carry out the received signal power measurement of initial AGC, received signal power in the sub-frame of uplink time all can be added up interior, very easily cause because the signal power that receives is excessive or too smallly cause directly reducing the signal quality for Cell searching, and reduce the problem of the sensitivity of Cell searching.

Therefore, the embodiment of the invention discloses the method and apparatus of a kind of initial AGC of LTE system.Obtain AGC control word by the mode of Quick Measurement, quick adjustment, as shown in Figure 3, the process of the disclosed initial AGC of the embodiment of the present invention mainly comprises the following steps:

Step S101, measures and receives the average power of signal and press the first Preset Time interval T _estsend.

Step S102, calculates described average power and goal-selling power P _normalbetween deviation, obtain gain error G _error.

Step S103, the first smoothing factor α is to described gain error G for foundation _errorcarry out smoothly, obtaining level and smooth gain error

Step S104, utilizes described level and smooth gain error upgrade current automatic gain control AGC yield value.

Step S105, the AGC yield value after conversion is upgraded, obtains AGC control word and by described the second Preset Time interval T _adjsend.

By the above-mentioned time domain sampling point based in sampling time interval, carry out the calculating of relevant power measurement and gain error and level and smooth process, finally generate and send AGC control word by the time interval, and make the data dimension of the descending sub frame that Cell searching uses be held in normal condition according to this AGC control word.The final signal quality improving for Cell searching, and the sensitivity that improves Cell searching.For the purpose of clearer, be elaborated below by following examples.

Embodiment mono-

On the basis of the disclosed technical scheme of the invention described above embodiment, refer to accompanying drawing 4, be the method flow diagram of the initial AGC of this embodiment of the invention one concrete disclosed a kind of LTE system, mainly comprise the following steps:

Step S201, measures and receives the average power P of signal and press the first Preset Time interval T _estsend.

In the process of execution above-mentioned steps S201, according to the first Preset Time interval T _estmeasure the average power P that receives signal, and according to this first Preset Time interval T _estsend this average power P.In order to carry out faster the fast conditioning function of AGC, in this embodiment mono-disclosed by the invention, choose the shorter time interval, choose this first Preset Time interval T _estfor the time span of an OFDM symbol specifying in LTE agreement, this time span comprise but and only limit to 71 microseconds, preferably situation is selected 71 microseconds.

In this embodiment mono-disclosed by the invention, step S201 specifically comprises the following steps:

Step S2011, described the first Preset Time interval T that calculating sampling arrives _estthe average power P of interior time domain sampling point N.

In the process of execution step S2011, the time-domain sampling point based on choosing, utilizes formula (1) to calculate the average power P of this time domain sampling point N:

$P=\underset{i=1}{\overset{N-1}{\mathrm{\Σ}}}(I_i^2+Q_i^2)/N---\left(1\right)$

In this formula (1), utilize the range value of time domain sampling point: S _i=I _i+ j*Q _i; Wherein, S _ifor complex signal, be divided into I, Q two-way, i=0,1 ..., N-1, N is counting of the described time domain sampling point that samples.

It should be noted that, the points N of the time domain sampling point that this samples can be the first Preset Time interval T _estinterior all number of samples can be also this first Preset Time interval T of choosing at continuous or interval _estinterior part number of samples.In disclosed this embodiment taking 2 power side as benchmark, in this first Preset Time interval T _estin continuously or interval choose number of samples.But the value of N is not limited in the disclosed value of the embodiment of the present invention, can carry out according to specific needs value.

Step S2012, changes the described average power P of time domain sampling point into dB value, is designated as P _dB.

Step S2013, by described the first Preset Time interval T _estsend the P after conversion _dB.

In the process of execution step S2012, utilize formula (2) to change, obtain P _dB:

P _dB＝10*log ₁₀(P) (2)

Wherein, P is the average power of time domain number of samples N.From execution step S2011, in the first Preset Time interval T _estinside choose time domain sampling point, especially preferably, the power side taking 2 is benchmark, in this first Preset Time interval T _estin continuously or interval choose number of samples, can effectively reduce the amount of calculation in formula (1), and then the power measurement of collecting mail number that achieves a butt joint more efficiently.

Step S202, calculates described average power P _dBwith goal-selling power P _normalbetween deviation, obtain gain error G _error.

In step S202, from formula (2), average power P _dBfor the dB value of average power P, calculating after this adopts this dB value.Obtain described average power P _dBwith goal-selling power P _normalbetween the process of deviation, as shown in formula (3):

G _error＝P _dB-P _normal (3)

Wherein, goal-selling power P _normalphysical significance be the input signal power value that system is expected, this value can be by presetting according to the performance requirement of the concrete scene using and concrete terminal equipment, and adaptive adjustment.P _dBfor being converted to the average power P of dB value.

This gain error G _errorrelevant to current AGC yield value, its physical significance is: if G _error> 0, represents that the power of current time-domain signal is greater than target power, the current gain of AGC need to be turned down; If G _error< 0, represents that the power of current time-domain signal is less than target power, the current gain of AGC need to be tuned up; If G _error=0, represent that the power of current time-domain signal equals target power, the current gain that maintains AGC is constant.

Step S203, the first smoothing factor α is to described gain error G for foundation _errorcarry out smoothly, obtaining level and smooth gain error

In execution step S203, utilize the first smoothing factor α to described gain error G _errorcarry out smoothly, in this embodiment disclosed in this invention, adopt the mode as shown in formula (4) to carry out smoothly:

${\stackrel{\&OverBar;}{G}}_{\mathrm{error}}={\stackrel{\&OverBar;}{G}}_{\mathrm{error}}\&times;(1-\mathrm{\&alpha;})+G_{\mathrm{error}}\&times;\mathrm{\&alpha;}---\left(4\right)$

Wherein, for the gain error after level and smooth, its initial value is 0; α is the first smoothing factor, and generally its span is 0≤α≤1.

In embodiment mono-disclosed by the invention, preferably span is: 0.1≤α≤0.5, adopts the first smoothing factor α within the scope of this can realize the fast conditioning function of initial AGC.

Step S204, utilizes described level and smooth gain error upgrade current AGC yield value G ₀, obtain the AGC gain after renewal.

Execution step S204 upgrades current AGC yield value G ₀mainly comprise:

Step S2041, obtains described gain error G _errorgain error after carrying out smoothly and current AGC yield value G ₀.

In step S2041, current AGC yield value G ₀initial value be 0.

Step S2042, the initial value of described current AGC yield value is 0, judges the size of described level and smooth gain error, if described level and smooth gain error is greater than at 1 o'clock, performs step S2043; If described level and smooth gain error is less than at 1 o'clock, perform step S2044; If when described level and smooth yield value equals zero, perform step S2045.

Step S2043, reduces described current AGC yield value G ₀, the value reducing is level and smooth gain error.

Step S2044, increases described current AGC yield value G ₀, the absolute value that the value increasing is level and smooth gain error.

Step S2045, maintains described current AGC yield value G ₀constant.

Specifically to current AGC yield value G ₀aGC yield value after the concrete renewal increasing or reduce is expressed as G, as shown in formula (5):

$G=G_0-{\stackrel{\&OverBar;}{G}}_{\mathrm{error}}---\left(5\right)$

Step S205, the AGC yield value after conversion is upgraded, obtains AGC control word and by described the second Preset Time interval T _adjsend.

The current AGC yield value G after upgrading is converted to the discernible control word of radio frequency AGC module in LTE system (concrete transfer process can with reference to the service manual of LTE terminal equipment radio frequency chip) by execution step S205, and according to the second Preset Time interval T _adjfeed back to radio frequency AGC module.This second Preset Time interval T in this embodiment mono-disclosed by the invention _adjchoose the shorter time interval, to realize the fast conditioning function that carries out faster AGC.Preferably situation is 71 microseconds, is the time span of an OFDM symbol specifying in LTE agreement.But, this second Preset Time interval T _adjcomprise but and only limit to this 71 microsecond.

Pass through said process, time domain sampling point based in sampling time interval, carry out the calculating of relevant power measurement and gain error and level and smooth process, finally generate and send AGC control word by the time interval, and make the data dimension of the descending sub frame that Cell searching uses be held in normal condition according to this AGC control word.The final signal quality improving for Cell searching, and the sensitivity that improves Cell searching.

Embodiment bis-

On the basis of the disclosed technical scheme of the invention described above embodiment, refer to accompanying drawing 5, be the method flow diagram of the initial AGC of this embodiment of the invention two concrete disclosed a kind of LTE systems, mainly comprise the following steps:

Step S301, measures and receives the average power P of signal and press the first Preset Time interval T _estsend.

Carrying out the first Preset Time interval T described in the process of above-mentioned steps S301 _estspan identical with scope of disclosure in above-described embodiment one, no longer repeat here.

In the process of specifically obtaining average power of this step S301 and embodiment mono-, disclosed process is different, specifically comprises the following steps:

Step S3011, described the first Preset Time interval T of sampling _estin time domain sampling point N, the power of node-by-node algorithm time domain sampling point described in each.

Step S3012, according to the second smoothing factor β, carries out smoothly, obtaining average power P to the power of time domain sampling point N described in each continuously.

Execution step S3012 carries out level and smooth process as shown in formula (6) to the power of time domain sampling point N described in each:

$P=P_0\&times;(1-\mathrm{\&beta;})+(I_i^2+Q_i^2)\&times;\mathrm{\&beta;}---\left(6\right)$

Wherein, P ₀for initial average power, initial value is 0, every level and smooth through a sampling point, P ₀be updated to the value of P; The range value of described time domain sampling point is: S _i=I _i+ j*Q _i, wherein, S _ifor complex signal, be divided into I, Q two-way, i=0,1 ..., N-1, N is counting of the described time domain sampling point that samples, the process of this sampling time domain sampling point N is identical with disclosed process in above-described embodiment one, repeats no more here.β is the second smoothing factor, and generally its span is 0≤β≤1, described β preferably value including but not limited to 1/128.In embodiment bis-disclosed by the invention, adopt the second smoothing factor β within the scope of this can realize the fast conditioning function of initial AGC.

Step S3013, changes described average power P into dB value, is designated as P _dB, and by described the first Preset Time interval T _estsend this average power P _dB.

In the process of execution step S3013, utilize formula (7) to change, obtain P _dB:

P _dB＝10*log ₁₀(P) (7)

Wherein, P gets average power after carrying out smoothly to the power of time domain sampling point N described in each.

Step S302, calculates described average power P _dBwith goal-selling power P _normalbetween deviation, obtain gain error G _error.

Step S303, the first smoothing factor α is to described gain error G for foundation _errorcarry out smoothly, obtaining level and smooth gain error

Step S304, utilizes described level and smooth gain error upgrade current AGC yield value G ₀, obtain the AGC gain G after renewal.

Step S305, the AGC yield value after conversion is upgraded, obtains AGC control word and by described the second Preset Time interval T _adjsend.

The concrete implementation of above-mentioned steps S302～step S305 is consistent with the step S202～step S205 in above-mentioned disclosed embodiment mono-, can mutually carry out reference, no longer repeats here.

Pass through said process, the same time domain sampling point based in sampling time interval, carry out the calculating of relevant power measurement and gain error and level and smooth, can finally generate and send AGC control word by the time interval, and make the data dimension of the descending sub frame that Cell searching uses be held in normal condition according to this AGC control word.Realize the signal quality improving for Cell searching, and improve the object of the sensitivity of Cell searching.

In the disclosed embodiment of the invention described above, describe the method for initial AGC of LTE system a kind of in detail, can adopt the equipment of various ways to realize for said method disclosed by the invention, therefore the invention also discloses the equipment of the initial AGC of the LTE system of corresponding said method, provide specific embodiment below and be elaborated.

Refer to accompanying drawing 6, for the equipment of the AGC of the disclosed a kind of Long Term Evolution LTE system of the embodiment of the present invention, mainly comprise: signal power measurement unit 305, gain error computing unit 306, gain error smooth unit 307, AGC control word generation unit 308 and AGC control unit 309.

LNA/VGA unit 301, AD conversion unit 302, low-pass filter unit 303 and FFT unit 304 in accompanying drawing 6 are the receiving terminal part of LTE system.

Signal power measurement unit 305, for pressing the first Preset Time interval measurement T _estreceive the average power of signal, and by described the first Preset Time interval T _estsend described average power.

Gain error computing unit 306, for calculating described average power and goal-selling power P _normalbetween deviation, obtain gain error G _error.

For the implementation of gain error computing unit 306, can, referring to the record of calculating about gain error in the disclosed embodiment mono-of the invention described above and embodiment bis-, repeat no more here.

Gain error smooth unit 307, for according to the first smoothing factor to described gain error G _errorcarry out smoothly, obtaining level and smooth gain error

For the implementation of gain error smooth unit 307, can, referring to the level and smooth process of gain error of recording in the disclosed embodiment mono-of the invention described above and embodiment bis-, repeat no more here.

AGC control word generation unit 308, for utilizing described level and smooth gain error upgrade current automatic gain control AGC yield value, and the AGC yield value of conversion after upgrading, generate AGC control word that described AGC yield value is corresponding and by the second Preset Time interval T _adjsend.

For the implementation of AGC control word generation unit 308, can, referring to the process of the generation AGC control word of recording in the disclosed embodiment mono-of the invention described above and embodiment bis-, repeat no more here.

AGC control unit 309, exports the first Preset Time interval T for comprising to described signal power measurement unit 305 _est, export goal-selling power P to described gain error computing unit 306 _normal, export the first smoothing factor α to described gain error smooth unit 307, and send the second Preset Time interval T of AGC control word to described AGC control word generation unit 308 outputs _adj.

For carrying out to received signal power measurement in signal power measurement unit 305, obtain the average power that receives signal.Comprise that in this power measurement unit 305 concrete two kinds of structures obtain average power.

Wherein, as shown in Figure 6, in described power measurement unit 305, mainly comprise: sampling unit 3051, computing unit 3052 and converting unit 3053.

Sampling unit 3051, for described the first Preset Time interval T of sampling _estinterior time domain sampling point N.

Computing unit 3052, for calculating the average power P of described time domain sampling point.

Converting unit 3053, for changing described average power P into dB value, by described the first Preset Time interval T _estsend.

Implementation in above-mentioned unit, specifically can, referring to the record in the step S2011～step S2013 in embodiment mono-disclosed by the invention, therefore, no longer repeat here.

Wherein, as shown in Figure 7, in described power measurement unit 405, mainly comprise: sampling unit 4051, smooth unit 4052 and converting unit 4053.

Sampling unit 4051, for described the first Preset Time interval T of sampling _estinterior time domain sampling point N;

Smooth unit 4052, for the power of node-by-node algorithm time domain sampling point N described in each, and carries out smoothly, obtaining average power P to the power of time domain sampling point N described in each continuously;

Converting unit 4053, for changing described average power into dB value, by described the first Preset Time interval T _estsend.

Implementation in above-mentioned unit, identical with the record in step S3011～step S3013 in embodiment bis-disclosed by the invention, can be referring to, no longer repeat here.

It should be noted that, in accompanying drawing 7, what LNA/VGA unit 401, AD conversion unit 402, low-pass filter unit 403 and FFT unit 404 were the receiving terminal part of LTE system with Fig. 6 is 301～304 identical, repeats no more here; Gain error computing unit 406, gain error smooth unit 407, AGC control word generation unit 408 and AGC control unit 409 in accompanying drawing 7, the process performed with gain error computing unit 306, gain error smooth unit 307, AGC control word generation unit 308 and AGC control unit 309 in accompanying drawing 6 is identical, and can reference, no longer repeat here.

In sum:

By the record in the disclosed embodiment of the invention described above, time domain sampling point based in sampling time interval, carry out the calculating of relevant power measurement and gain error and level and smooth, finally generate and send AGC control word by the time interval, and make the data dimension of the descending sub frame that Cell searching uses be held in normal condition according to this AGC control word.By the mode of Quick Measurement and quick adjustment, final realization improved the signal quality that is used for Cell searching, and improves the object of Cell searching sensitivity.

In this specification, each embodiment adopts the mode of going forward one by one to describe, and what each embodiment stressed is and the difference of other embodiment, between each embodiment identical similar part mutually referring to.For the disclosed device of embodiment, because it corresponds to the method disclosed in Example, so description is fairly simple, relevant part illustrates referring to method part.

The software module that the method for describing in conjunction with embodiment disclosed herein or the step of algorithm can directly use hardware, processor to carry out, or the combination of the two is implemented.Software module can be placed in the storage medium of any other form known in random asccess memory (RAM), internal memory, read-only memory (ROM), electrically programmable ROM, electrically erasable ROM, register, hard disk, moveable magnetic disc, CD-ROM or technical field.

To the above-mentioned explanation of the disclosed embodiments, make professional and technical personnel in the field can realize or use the present invention.To be apparent for those skilled in the art to the multiple amendment of these embodiment, General Principle as defined herein can, in the situation that not departing from the spirit or scope of the present invention, realize in other embodiments.Therefore, the present invention will can not be restricted to these embodiment shown in this article, but will meet the widest scope consistent with principle disclosed herein and features of novelty.

Claims (9)

1. a method of the initial automatic gain control AGC of Long Term Evolution LTE system, is characterized in that, comprising:

Receive the average power of signal by the first Preset Time interval measurement and transmission;

Calculate the deviation between described average power and goal-selling power, obtain gain error;

According to the first smoothing factor, described gain error is carried out smoothly, obtaining level and smooth gain error;

Utilize described level and smooth gain error to upgrade current automatic gain control AGC yield value;

AGC yield value after conversion is upgraded, obtains AGC control word and sends by the second Preset Time interval;

Wherein, according to the first smoothing factor, described gain error is carried out smoothly, the process that obtains level and smooth gain error comprises:

Obtain described the first smoothing factor, and receive described gain error;

Based on smooth manner, obtain described level and smooth gain error;

Wherein, G _errorfor described gain error, for described level and smooth gain error, α is the first smoothing factor, and the span of described α is 0.1～0.5.

2. method according to claim 1, is characterized in that, the described process by the average power of the first Preset Time interval measurement and transmission reception signal comprises:

The average power P of the time domain sampling point in described the first Preset Time interval that calculating sampling arrives;

The range value of described time domain sampling point is: S _i=I _i+ j*Q _i, wherein, S _ifor complex signal, be divided into I, Q two-way, i=0,1 ..., N-1, N is counting of the described time domain sampling point that grabs; Described average power $P=\underset{i=0}{\overset{N-1}{\mathrm{\&Sigma;}}}(I_i^2+Q_i^2)/N;$

Change described average power P into dB value, send by described the first Preset Time interval.

3. method according to claim 1, is characterized in that, the described process by the average power of the first Preset Time interval measurement and transmission reception signal comprises:

The time domain sampling point of sampling in described the first Preset Time interval, the power of node-by-node algorithm time domain sampling point described in each;

According to the second smoothing factor, utilize continuously the power of time domain sampling point described in each is carried out smoothly, obtaining average power P;

Wherein, β is the second smoothing factor, and the value of described β comprises 1/128, P ₀for initial average power value is 0, and every level and smooth through a sampling point, P ₀be updated to the value of P; The range value of described time domain sampling point is: S _i=I _i+ j*Q _i, wherein, S _ifor complex signal, be divided into I, Q two-way, i=0,1 ..., N-1, N is counting of the described time domain sampling point that grabs,

Change described average power P into dB value, send by described the first Preset Time interval.

4. according to the method in claim 2 or 3, it is characterized in that, the points N of described time domain sampling point comprises all number of samples in the first Preset Time interval;

Or, the part number of samples continuously or in the described first Preset Time interval of choosing at interval, the span of described part number of samples is: 2 power side.

5. according to the method described in any one in claim 1～3, it is characterized in that, the process of utilizing described level and smooth gain error to upgrade current AGC yield value comprises:

Obtain the gain error after carrying out smoothly to described gain error, and current AGC yield value;

The initial value of described current AGC yield value is 0, and the process of upgrading described current AGC yield value is;

In the time that described level and smooth gain error is greater than zero, reduce described current AGC yield value, the value reducing is level and smooth gain error;

In the time that described level and smooth gain error is less than zero, increase described current AGC yield value, the absolute value that the value increasing is level and smooth gain error;

In the time that described level and smooth gain error equals zero, maintain described current AGC yield value constant.

6. according to the method described in any one in claim 1～3, it is characterized in that, the value at described the first Preset Time interval comprises the time span of an orthogonal frequency division multiplex OFDM symbol;

The value at described the second Preset Time interval comprises the time span of an OFDM symbol.

7. an equipment of the initial automatic gain control AGC of Long Term Evolution LTE system, is characterized in that, comprising:

Signal power measurement unit, for receive the average power of signal by the first Preset Time interval measurement, and sends described average power by described the first Preset Time interval;

Gain error computing unit, for calculating the deviation between described average power and goal-selling power, obtains gain error;

Gain error smooth unit, for based on smooth manner described gain error is carried out smoothly, obtaining level and smooth gain error according to the first smoothing factor; Wherein, G _errorfor described gain error, for described level and smooth gain error, α is the first smoothing factor, and the span of described α is 0.1～0.5;

AGC control word generation unit, for utilizing described level and smooth gain error to upgrade current automatic gain control AGC yield value, and changes the AGC yield value after upgrading, and generates the AGC control word that described AGC yield value is corresponding and sends by the second Preset Time interval;

AGC control unit, be used for comprising to described signal power measurement unit and export the first Preset Time interval, to described gain error computing unit output goal-selling power, export the first smoothing factor to described gain error smooth unit, and send the second Preset Time interval of AGC control word to described AGC control word generation unit output.

8. equipment according to claim 7, is characterized in that, described signal power measurement unit comprises:

Sampling unit, for the time domain sampling point of sampling in described the first Preset Time interval;

Computing unit, for calculating the average power of described time domain sampling point;

Converting unit, for changing described average power into dB value, sends by described the first Preset Time interval.

9. equipment according to claim 7, is characterized in that, described signal power measurement unit comprises:

Sampling unit, for the time domain sampling point of sampling in described the first Preset Time interval;

Smooth unit, for the power of node-by-node algorithm time domain sampling point described in each, and carries out smoothly, obtaining average power to the power of time domain sampling point described in each according to the second smoothing factor continuously; Described the second smoothing factor is exported by described AGC control unit;

Converting unit, for changing described average power into dB value, sends by described the first Preset Time interval.