CN100508512C - Pulse noise suppression apparatus and method in orthogonal frequency-division multiplexing system - Google Patents

Abstract

The invention relates to an impulse noise suppression device and an impulse noise suppression method used in orthogonal frequency-division multiplex system, which can suppress the impulse noise in the first time domain signal to generate one output signal. Said device comprises: a impulse noise eliminate unit for treating said first time domain signal to generate the second time domain signal and control the absolute valve of second one is less than a preset valve; the first Fourier transform unit for transforming the second time domain signal to generate a frequency domain signal; a identification module for identifying each sub carrier wave signals in said frequency domain signals to generate a identification signal; a decision unit for generating a decision signal according to said identification signal; and a compensation module for detecting the difference between said identification signal and the decision signal to correct said identification signal to output a signal.

Description

Be applied to the pulse noise suppression apparatus and the method thereof of ofdm system

Technical field

The present invention discloses a kind of pulse noise suppression apparatus and impulse noise suppression method, refers to a kind of pulse noise suppression apparatus and impulse noise suppression method that utilizes the decision-making re-establishment mechanism especially.

Background technology

Generally speaking, radio-frequency (RF) communication system can be subjected to more interference of noise compared to the communication system of wire transmission, for example: atmosphere (atmospheric) disturbs or artificial interference, wherein some interference source is to present with gaussian model, and other interference, for example: the noise that switch of electronics activator appliance (electricdiself-starter), power line, high electric current or the like is caused is to have quite high energy in very of short duration time, and the noise of this type promptly is called impulsive noise (impulsenoise).Because impulsive noise is one to have high-octane interference noise, so influence to received signal is even more serious than the noise of other form, therefore, for receiving terminal, how to detect and effectively the suppressor pulse noise be very important problem always.

With the radio-frequency (RF) communication system that is applied to audio-visual transmission is example, for example: digital television broadcasting system (Digital Video Broadcasting-Terrestrial, DVB-T), because having high-octane impulsive noise may make the message output equipment of receiving terminal produce sudden and violent sound or make display device image output noise, therefore can cause user's discomfort, so, when taking into account system designed, the designer often would rather the sacrificial section signal quality come the influence to received signal of suppressor pulse noise.Common impulse noise suppression method is the intensity of comparison one critical value and received signal, when the intensity of received signal during greater than this critical value, system can judge that the received signal of this sampling on time point is to be subjected to impulsive noise to disturb, and to force the value of setting received signal on this sampling time point be zero.See also Figure 1A, Figure 1A is the operation chart that known impulsive noise suppresses input signal with the sampling time point of mechanism.As shown in FIG., because input signal is a digital signal, so input signal all corresponding numerical value on each sampling time point is used for representing the signal strength signal intensity of input signal on each sampling time point.In Figure 1A, solid line is represented the actual represented numerical value of input signal, also is the signal strength signal intensity of input signal, and dotted portion is then represented the intensity of impulsive noise, for example: at sampling time point t _bOn, the signal strength signal intensity of input signal is " 3 ", but is influenced because of being subjected to the impulsive noise of an intensity by " 6 ", and makes receiving terminal in sampling time point t _bLast the actual received signal that detects becomes " 9 ".At this moment, if above-mentioned critical value setting is " 8 ", then receiving terminal just can be judged sampling time point t _bSignal be to be subjected to impulsive noise to disturb, so force to set sampling time point t _bThe numerical value of pairing output signal is " 0 "; In like manner, receiving terminal also will force to set sampling time point t _a, t _c, t _dThe numerical value of pairing output signal is " 0 ".Shown in Figure 1B.Hence one can see that, suppressed sampling time point t though known impulsive noise suppresses mechanism _a, t _b, t _c, t _dOn impulsive noise (time point t for example takes a sample _bImpulsive noise intensity be " 6 "), but also sacrificed simultaneously at sampling time point t _a, t _b, t _c, t _d(last input signal is originally for example taken a sample time point t _bInput signal strength be " 3 ") cause the distortion of signal.

In some application system, because the restriction of human sense organ may not be certain can discover the phenomenon of this distortion, for example: for image transmission system, the user can not discover the otherness of some pixels on the picture usually, so, if the signal that only is several sampling time points has a little distortion, can't cause too much influence to the user who views and admires, and this characteristic also is applicable to the situation of message transmission system.But because the quality of audio-visual devices promotes day by day, the user is more and more higher to the requirement of image quality and tonequality, though above-mentioned impulsive noise suppresses mechanism suppressor pulse noise effectively, but signal quality that but can sacrificial section makes known technology can't verily present the audiovisual materials that the tendency to develop of original institute is sent.

Summary of the invention

Therefore, one of main purpose of the present invention is to provide a kind of pulse noise suppression apparatus and impulse noise suppression method that utilizes the decision-making re-establishment mechanism, to address the above problem.

According to claim of the present invention, it is to disclose a kind of impulsive noise to suppress (impulsenoise suppression) device.This pulse noise suppression apparatus is to be applied to an OFDM (Orthogonal Frequency Division Multiplexing, OFDM) communication system, in order to suppress impulsive noise in one first time-domain signal to produce an output signal, wherein this first time-domain signal is a kind of OFDM time-domain signal, this OFDM time-domain signal can get an OFDM frequency-region signal through conversion, and this OFDM frequency-region signal is made up of a plurality of sub-carrier signal.This pulse noise suppression apparatus includes: an impulsive noise is eliminated unit (noiseblanker), be used for handling this first time-domain signal, to produce one second time-domain signal, wherein if in a time point, the value of this first time-domain signal is greater than one first critical value, then this impulsive noise elimination unit is that this second time-domain signal of control makes its absolute value be not more than a predetermined value, this predetermined value can be zero, and if in a time point, the value of this first time-domain signal is not more than this first critical value, and then this impulsive noise elimination unit is a value of setting this second time-domain signal according to the value of this first time-domain signal; One first Fu Li leaf converting unit is electrically connected to this impulsive noise and eliminates the unit, in order to change this second time-domain signal to produce one second frequency-region signal; The first-classization module, be electrically connected to this first Fu Li leaf converting unit, be used for according to corresponding to each sub-carrier signal in these second frequency-region signals of change such as a channel estimation value of each sub-carrier channels of this orthogonal FDM communication system to produce the first-classization signal, wherein these change signals are made up of a plurality of equating signal values, and the corresponding subcarrier of each equating signal value difference; One decision package, be electrically connected to these and change module, be used for changing signal and produce a decision signal according to these, wherein this decision signal is made up of a plurality of decision signal values, and each decision signal value is a corresponding subcarrier respectively, this decision package can be decoded corresponding to these change signal values of a sub-carrier channels according at least one critical value, to produce this decision signal value corresponding to this sub-carrier channels, this decision package also can be according to a given value, to produce this decision signal value corresponding to a sub-carrier channels; An and compensating module, be electrically connected to these and change module and this decision package, be used for detecting the pairing time domain compensation signal of residual quantity that these change signal and this decision signal, and proofread and correct these according to the pairing frequency domain compensation signal of this time domain compensation signal and change signal to produce this output signal, wherein this output signal is made up of a plurality of output signal value, and the corresponding subcarrier of each output signal value difference.This pulse noise suppression apparatus can be applicable to a digital television system.

In addition, according to claim of the present invention, it discloses a kind of impulsive noise in addition and suppresses (impulse noise suppression) method.This impulse noise suppression method is to be applied to an OFDM (Orthogonal Frequency Division Multiplexing, OFDM) communication system, be used for suppressing impulsive noise in one first time-domain signal to produce an output signal, wherein this first time-domain signal is a kind of OFDM time-domain signal, this OFDM time-domain signal can get an OFDM frequency-region signal through conversion, and this OFDM frequency-region signal is made up of a plurality of sub-carrier signal, and this first time-domain signal is eliminated noise processed through pulse and obtained one second time-domain signal.This impulse noise suppression method includes: (a) if in a time point, the value of this first time-domain signal is greater than one first critical value, then controlling this second time-domain signal makes its absolute value be not more than a predetermined value, and if in a time point, the value of this first time-domain signal is not more than this first critical value, then sets the value of this second time-domain signal according to the value of this first time-domain signal; (b) Fu Liye changes this second time-domain signal to produce one second frequency-region signal; (c) according to corresponding to each sub-carrier signal in these second frequency-region signals of change such as a channel estimation value of each sub-carrier channels of this orthogonal FDM communication system to produce the first-classization signal, wherein these change signals are made up of a plurality of equating signal values, and each equating signal value is the corresponding subcarrier of difference; (d) these are changed signal and carry out decision-making treatment to produce a decision signal, wherein this decision signal is made up of a plurality of decision signal values, and each decision signal value is the corresponding subcarrier of difference; And the pairing time domain compensation signal of residual quantity of (e) detecting these change signals and this decision signal, and proofread and correct these according to the pairing frequency domain compensation signal of this time domain compensation signal and change signal to produce this output signal, wherein this output signal is made up of a plurality of output signal value, and each output signal value is the corresponding subcarrier of difference.

Pulse noise suppression apparatus of the present invention and impulse noise suppression method are to utilize a compensating module to calculate a frequency domain compensation signal, proofread and correct the first-classization signal to produce an output signal, also are a decision-making reconstruction signal.Therefore, pulse noise suppression apparatus of the present invention and impulse noise suppression method can make that this output signal is the frequency-region signal corresponding to one first time-domain signal, but its impulsive noise that can not be subjected in this first time-domain signal again influences.In addition, pulse noise suppression apparatus of the present invention and impulse noise suppression method can be adjusted the employed channel estimation value of ofdm system repeatedly, have preferable signal quality to make ofdm system further.

Description of drawings

Figure 1A is the operation chart that known impulsive noise suppresses input signal with the sampling time point of mechanism;

Figure 1B is that known impulsive noise suppresses the output signal of mechanism and the operation chart of sampling time point;

Fig. 2 is the function block schematic diagram of an embodiment of pulse noise suppression apparatus of the present invention;

Fig. 3 is the function block schematic diagram of compensating module shown in Figure 2;

Fig. 4 adjusts channel estimation value for pulse noise suppression apparatus shown in Figure 2 and produces the flow chart of output signal.

The primary clustering symbol description:

10 impulsive noises are eliminated unit 30,108 Fu Li leaf converting units

52 unit such as grade such as 50 modules such as grade

54 channel estimation unit, 70 decision packages

90 compensating modules, 100 pulse noise suppression apparatus

102 error arithmetic elements, 104 reverse Fu Li leaf converting units

106 compensation estimation unit, 110 correcting units

Embodiment

See also Fig. 2, Fig. 2 is the function block schematic diagram of an embodiment of pulse noise suppression apparatus 100 of the present invention.Pulse noise suppression apparatus 100 is to be used for suppressing an OFDM (OrthogonalFrequency Division Multiplexing, OFDM) impulsive noise of received signal (impulse noise) in the communication system, and the signal section that is suppressed in the received signal according to time domain assigns to compensate the pairing frequency-region signal of received signal, rebuilds (decision-aidedreconstruction) signal to produce a decision-making.As shown in FIG., in the present embodiment, pulse noise suppression apparatus 100 includes an impulsive noise and eliminates unit 10, a Fu Li leaf converting unit 30, first-classization module 50, a decision package 70 and a compensating module 90.It is to be used for handling a time domain received signal r to produce another time-domain signal r that impulsive noise is eliminated unit 10 _s, wherein, it is signal strength signal intensity and critical value V that compare time-domain signal r in each sampling time point that impulsive noise is eliminated unit 10 _TH, when the signal strength signal intensity of time domain signal r greater than critical value V _THThe time, then impulsive noise is eliminated unit 10 and is forced the time-domain signal r that exports on this sampling time point _sNumerical value be zero; Otherwise, then directly set the time-domain signal r that is exported on this sampling time point according to the numerical value of time-domain signal r on this sampling time point _sNumerical value.The running that impulsive noise is eliminated unit 10 please refer to following equation:

$r_s\left[i\right]=\left\{\begin{array}{cc}0,& \mathrm{if}\left|r\right[i\left]\right|>V_{\mathrm{TH}}\\ r\left[i\right],& \mathrm{otherwise}\end{array}\right.$ Equation (one)

In equation (), r[i] represent the numerical value of i the time-domain signal on the sampling time point, r[i] absolute value be designated as | r[i] | be r[i] signal strength signal intensity.

30 of Fu Li leaf converting units can be according to the frequency of each subcarrier in the ofdm system to time-domain signal r _sCarry out the Fu Liye conversion to produce a frequency-region signal R.Because ofdm system is to utilize a plurality of (for example: N) subcarrier to come the transmission data, so all can include N sub-carrier signal among each frequency-region signal R.Be provided with a first-classization unit 52 and a channel estimation unit 54 Deng in the change module 50, wherein, channel estimation unit 54 can calculate the channel estimation value H of each subcarrier _e, unit such as grade 52 is electrically connected to this channel estimation unit, and it is the channel estimation value H according to each subcarrier _eCome corresponding sub-carrier signal among the R such as frequency-region signal such as gradeization, and produce first-classization signal S _Eq, therefore, each equating signal S _EqIn all include N the equating signal value that corresponds to different sub carrier respectively; This channel estimation unit is that each subcarrier is calculated a updating value corresponds to this subcarrier with renewal this channel estimation value, wherein this updating value is that this output signal value that corresponds to this subcarrier multiply by this channel estimation value that corresponds to this subcarrier, again divided by this decision signal value that corresponds to this subcarrier.Decision package 70 be at etc. the equating signal S that produced of change module 50 _EqCarry out decision-making treatment (hard-decision) to produce a decision signal S _d, similarly, each decision signal S _dIn also include N the decision signal value that corresponds to different sub carrier respectively.It is noted that, because some subcarrier in the ofdm system is decided to be the role of pilot channel (pilot channel) in, in order to transmit so-called boot symbol unit (pilot symbol), wherein this boot symbol unit is known numerical value, so equating signal S _EqIn corresponding to the part of those pilot channel, decision package 70 does not need actually to carry out decision-making treatment, but directly with decision signal S _dIn be this known boot symbol unit numerical value corresponding to the setting value of those pilot channel.Then, compensating module 90 can be according to equating signal S _Eq, decision signal S _dAnd N channel estimation value H _e, calculate a frequency domain compensation signal S _c, and according to frequency domain compensation signal S _cCompensation equating signal S _EqProduce an output signal S _Out, wherein the detailed operation mode of compensating module 90 will describe in detail hereinafter one by one.

See also Fig. 3, Fig. 3 is the function block schematic diagram of compensating module 90 shown in Figure 2.As shown in FIG., be provided with an error arithmetic element 102, one reverse Fu Li leaf converting unit 104, compensation estimation unit 106, a Fu Li leaf converting unit 108 and a correcting unit 110 in the compensating module 90.Error arithmetic element 102 is electrically connected these and changes module and this decision package, and it is to be used for detecting equating signal S _EqWith decision signal S _dBetween residual quantity, and the channel estimation value H that utilizes aforementioned channels estimation unit 54 to be exported _eAdjust this residual quantity to produce a frequency domain error signal S _EirThe running of error arithmetic element 102 please refer to following equation:

$S_{\mathrm{err}}^{\left(m\right)}\left[i\right]=(S_{\mathrm{eq}}^{\left(m\right)}\left[i\right]-S_d^{\left(m\right)}\left[i\right])\·H_e^{\left(m\right)}\left[i\right],m=\mathrm{1,2},...,N$ Equation (two)

When not having the interference of any noise or impulsive noise ideally in the communication channel, this promptly, time-domain signal r _sShould equal time-domain signal r, and channel estimation value H _eAll be 1 o'clock ideally, channel response can not have any impact to frequency-region signal R yet yet, at this moment, and decision signal S _dValue should equal equating signal S _EqValue.Yet practical situation is really not so, so error arithmetic element 102 must calculate equating signal S earlier _EqWith decision signal S _dBetween residual quantity, and residual quantity is multiplied by channel estimation value H _eTo produce a frequency domain error signal S _ErrThen, reverse Fu Li leaf converting unit 104 is further with frequency domain error signal S _ErrBe converted to a time domain error signal s _Err, this reverse Fu Li leaf converting unit is to be electrically connected to this error arithmetic element, at this moment, and time domain error signal s _ErrPromptly the data signal composition of eliminating among the time-domain signal r of unit 10 extra inhibition of institute in the suppressor pulse noise with impulsive noise is relevant.Impulsive noise and eliminate data signal composition among the extra time-domain signal r that suppresses of unit 10 institute in the suppressor pulse noise in order to estimate, compensation is estimated unit 106 and is utilized another critical value V _TH2Judge time domain error signal s _ErrTo produce a time domain compensation signal s _c Compensation estimation unit 106 is electrically connected to this reverse Fu Li leaf converting unit, and it is to compare critical value V on each sampling time point _TH2With time domain error signal s _Err, if time domain error signal s _ErrAbsolute value greater than critical value V _TH2The time, then according to time domain error signal S _ErrNumerical value set time domain compensation signal s on this sampling time point _cNumerical value, if time domain error signal s _ErrAbsolute value be not more than critical value V _TH2Then set time domain compensation signal s _ErrNumerical value be zero.Thus, time domain compensation signal s _ErrPromptly can be considered impulsive noise and eliminate the influence that the 10 couples of time-domain signal r in unit cause, just time-domain signal r is eliminated 10 the related signal components that curb in unit by impulsive noise.The running of compensation estimation unit 106 please refer to following equation:

$s_c^{\left(m\right)}\left[i\right]=\left\{\begin{array}{cc}{s}_{\mathrm{err}}^{\left(m\right)}\left[i\right],& \mathrm{if}\left|s_{\mathrm{err}}^{\left(m\right)}\right[i\left]\right|>V_{\mathrm{TH}2}\\ 0,& \mathrm{otherwise}\end{array}\right.,m=\mathrm{1,2},...,N$ Equation (three)

Then, Fu Li leaf converting unit 108 is with time domain compensation signal s _cBe converted to a preliminary frequency domain compensation signal S _c, this Fu Li leaf converting unit 108 is to be electrically connected to this compensation estimation unit.At last, correcting unit 110 can utilize channel estimation value H _eAdjust preliminary frequency domain compensation signal S _cProducing a frequency domain compensation signal, and compensate equating signal S according to this frequency domain compensation signal _EqTo produce output signal S _Out, at this moment, output signal S _OutBe equating signal S _EqThe decision-making reconstruction signal.This correcting unit is to be electrically connected to this decision package and this second Fu Li leaf converting unit, and it is to utilize these to change signal to deduct this frequency domain compensation signal to produce this output signal.The running of correcting unit 110 please refer to following equation:

$S_{\mathrm{om}}^{\left(m\right)}\left[i\right]=S_{\mathrm{eq}}^{\left(m\right)}\left[i\right]-\frac{S_c^{\left(m\right)}\left[i\right]}{H_e^{\left(m\right)}\left[i\right]},m=\mathrm{1,2},...,N$ Equation (four)

In addition, according to equation (four), can be with S _OutValue, set to give S _Eq, and then overlap and get back to equation (two), do second computing of taking turns, the so many computing of doing several samsaras can further reach better impulsive noise and suppress effect.

Because above-mentioned computing, much all with channel estimation value H _eRelevant, so channel estimation value H _eAccuracy just very important.According to the present invention, channel estimation value H _eAccuracy can further improve, utilize the boot symbol unit that pilot channel transmits to be known characteristic, channel estimation value H _eCan do renewal according to following equation:

$\frac{S_{\mathrm{out}}^{\left(m\right)}\·H_e^{\left(m\right)}}{S_d^{\left(m\right)}}\→H_e^{\left(m\right)}$ Equation (five)

Wherein, m is the label of a certain pilot channel, at this moment,

Be the boot symbol unit that this pilot channel transmitted.Channel estimation value H _eRenewal can cooperate the computing of above-mentioned each samsara, so after the circulation for several times, can further reach better impulsive noise and suppress effect.Note that and adjust channel estimation value H among the present invention _eMethod do not exceed with the described boot symbol unit that utilizes of present embodiment, other improves decision signal S _dMethod of accuracy also can be adjusted channel estimation value H according to equation (five) _e

In order to describe the operation workflow of pulse noise suppression apparatus 100 of the present invention in detail, see also Fig. 4, Fig. 4 is that pulse noise suppression apparatus 100 shown in Figure 2 is adjusted channel estimation value H _eAnd generation output signal S _NutFlow chart.The running of pulse noise suppression apparatus 100 comprises the following step:

Step 200: beginning;

Step 202: time-domain signal r is carried out impulsive noise eliminate (impulse blanking) processing to produce time-domain signal r _s

Step 204: Fu Liye changes this time-domain signal r _bTo produce a frequency-region signal R;

Step 206: according to channel estimation value H _eDeng changing this frequency-region signal R to produce first-classization signal S _Eq

Step 208: these are changed signal S _EqCarry out decision-making treatment to produce a decision signal S _d

Step 212: calculate this decision signal S _dChange signal S with these _EqBetween a frequency domain error signal S _Err

Step 214: reverse Fu Li leaf is changed this frequency domain error signal S _ErrTo produce a time domain error signal S _Err

Step 216: according to this time domain error signal s _Err, estimate a time domain compensation signal s _c

Step 218: Fu Liye changes this time domain compensation signal s _cTo produce a preliminary frequency domain compensation signal S _c

Step 222: according to this preliminary frequency domain compensation signal S _cCompensate these and change signal S _EqTo produce output signal S _Out

Except producing correct output signal S _OutOutside, present embodiment is in addition in hereinafter disclosing output signal S _OutValue set to equating signal S _EqMethod (step 224), repeated execution of steps 208～222 then, the so many computing of doing several samsaras can further reach better impulsive noise and suppress effect.In addition, channel estimation value H _eCan cooperate the computing of above-mentioned each samsara to be upgraded, so after the circulation for several times, can further reach better impulsive noise and suppress effect.Set equating signal S _EqWith renewal channel estimation value H _eStep as follows:

Step 224: utilize output signal S _OutValue set equating signal S _Eq, and to each pilot channel (for example label is the pilot channel of m), according to output signal S _OutTo value that should pilot channel (promptly The known guide symbol unit value that this pilot channel transmitted (promptly

), and present channel estimation value H _eTo value that should pilot channel (promptly

), upgrade this channel estimation value Value.

The impulse noise suppression method of this embodiment of the invention is as follows:

Impulse noise suppression method is applied to an orthogonal FDM communication system, be used for suppressing impulsive noise in one first time-domain signal to produce an output signal, wherein this first time-domain signal is a kind of OFDM time-domain signal, this OFDM time-domain signal can get an OFDM frequency-region signal through conversion, and this OFDM frequency-region signal is made up of a plurality of sub-carrier signal, and this impulse noise suppression method includes:

(a) if in a time point, the value of this first time-domain signal is greater than one first critical value, then controlling this second time-domain signal makes its absolute value be not more than a predetermined value, and if in a time point, the value of this first time-domain signal is not more than this first critical value, then sets the value of this second time-domain signal according to the value of this first time-domain signal;

(b) Fu Liye changes this second time-domain signal to produce a frequency-region signal;

(c) according to corresponding to each sub-carrier signal in these frequency-region signals of change such as a channel estimation value of each sub-carrier channels of this orthogonal FDM communication system to produce the first-classization signal, wherein these change signals are made up of a plurality of equating signal values, and each equating signal value is the corresponding subcarrier of difference;

(d) produce a decision signal, wherein this decision signal is made up of a plurality of decision signal values, and each decision signal value is the corresponding subcarrier of difference; And

(e) detect the pairing time domain compensation signal of residual quantity that these change signal and this decision signal, and proofread and correct these according to the pairing frequency domain compensation signal of this time domain compensation signal and change signal to produce this output signal, wherein this output signal is made up of a plurality of output signal value, and each output signal value is the corresponding subcarrier of difference.

Wherein step (d) is to decode corresponding to these change signal values of a sub-carrier channels, to produce this decision signal value corresponding to this sub-carrier channels according at least one critical value.

Wherein step (d) is according to a given value, to produce this decision signal value corresponding to a sub-carrier channels.

Wherein step (e) includes:

(f) according to this channel estimation value, these change the residual quantity of signal and this decision signal computing, to produce a frequency domain error signal;

(g) reverse Fu Li leaf is changed this frequency domain error signal to produce a time domain error signal;

(h) estimate according to this time domain error signal and a time domain compensation signal;

(i) Fu Liye changes this time domain compensation signal to produce a preliminary frequency domain compensation signal; And

(j) according to this channel estimation value, this preliminary frequency domain compensation signal of computing to be producing this frequency domain compensation signal, and uses this frequency domain compensation signal to proofread and correct these and change signals to produce this output signal.

Wherein step (h) is relatively this time domain error signal and one second critical value, if in a time point, the value of this time domain error signal is greater than this second critical value, then set the value of this time domain compensation signal according to the value of this time domain error signal, and if the value of this time domain error signal is not more than this second critical value, the value of then setting this time domain compensation signal is zero.

Wherein step (j) is to utilize these to change signal to deduct this frequency domain compensation signal to produce this output signal.

Wherein step (c) includes:

(k) calculate this channel estimation value; And

(1) changes signal according to this frequency-region signals of change such as this channel estimation value to produce these.

Wherein after step (e) produces this output signal, step (k) decision signal that to be the output signal that produces according to step (e) produced with step (d), and this present channel estimation value are upgraded this channel estimation value.

Wherein step (k) is that each subcarrier is calculated a updating value corresponds to this subcarrier with renewal channel estimation value, wherein this updating value is that this output signal value that corresponds to this subcarrier multiply by the channel estimation value that corresponds to this subcarrier, again divided by this decision signal value that corresponds to this subcarrier.

This impulse noise suppression method can be applicable to a digital television system.

The described predetermined value of this impulse noise suppression method can be zero.

Compared to known technology, pulse noise suppression apparatus of the present invention and impulse noise suppression method utilize a compensating module to estimate a frequency domain compensation signal equating signal are compensated to produce a decision-making reconstruction signal, simultaneously progressively adjust the employed channel estimation value of ofdm system, so that ofdm system has preferable signal quality.

The above only is preferred embodiment of the present invention, and all equalizations of being done according to the present patent application claim change and modify, and all should belong to covering scope of the present invention.

Claims (22)

1, a kind of pulse noise suppression apparatus that is applied to ofdm system, it is characterized in that, it is applied to an orthogonal FDM communication system, in order to suppress impulsive noise in one first time-domain signal to produce an output signal, wherein this first time-domain signal is a kind of OFDM time-domain signal, this OFDM time-domain signal can get an OFDM frequency-region signal through conversion, and this OFDM frequency-region signal is made up of a plurality of sub-carrier signal, and this pulse noise suppression apparatus includes:

One impulsive noise is eliminated the unit, be used for handling this first time-domain signal, to produce one second time-domain signal, wherein if in a time point, the value of this first time-domain signal is greater than one first critical value, then this impulsive noise elimination unit is that this second time-domain signal of control makes its absolute value be not more than a predetermined value, and if in a time point, the value of this first time-domain signal is not more than this first critical value, and then this impulsive noise elimination unit is a value of setting this second time-domain signal according to the value of this first time-domain signal;

One first Fu Li leaf converting unit is electrically connected to this impulsive noise and eliminates the unit, in order to change this second time-domain signal to produce one second frequency-region signal;

The first-classization module, be electrically connected to this first Fu Li leaf converting unit, be used for according to corresponding to each sub-carrier signal in these second frequency-region signals of change such as a channel estimation value of each sub-carrier channels of this orthogonal FDM communication system to produce the first-classization signal, wherein these change signals are made up of a plurality of equating signal values, and each equating signal value is the corresponding subcarrier of difference;

One decision package is electrically connected to these and changes module, is used for changing signal according to these and produces a decision signal, and wherein this decision signal is made up of a plurality of decision signal values, and each decision signal value is the corresponding subcarrier of difference; And

One compensating module, be electrically connected to these and change module and this decision package, be used for detecting the pairing time domain compensation signal of residual quantity that these change signal and this decision signal, and proofread and correct these according to the pairing frequency domain compensation signal of this time domain compensation signal and change signal to produce this output signal, wherein this output signal is made up of a plurality of output signal value, and each output signal value is the corresponding subcarrier of difference.

2, pulse noise suppression apparatus as claimed in claim 1 is characterized in that, wherein this decision package is to decode corresponding to these change signal values of a sub-carrier channels, to produce this decision signal value corresponding to this sub-carrier channels according at least one critical value.

3, pulse noise suppression apparatus as claimed in claim 1 is characterized in that, wherein this decision package is according to a given value, to produce this decision signal value corresponding to a sub-carrier channels.

4, pulse noise suppression apparatus as claimed in claim 1 is characterized in that, wherein this compensating module includes:

One error arithmetic element is electrically connected to these and changes module and this decision package, is used for the residual quantity of these change signals of computing and this decision signal, and according to this this residual quantity of channel estimation value computing to produce a frequency domain error signal;

One reverse Fu Li leaf converting unit is electrically connected to this error arithmetic element, is used for reverse Fu Li leaf to change this frequency domain error signal to produce a time domain error signal;

One compensation estimation unit is electrically connected to this reverse Fu Li leaf converting unit, is used for estimating according to this time domain error signal a time domain compensation signal;

One second Fu Li leaf converting unit is electrically connected to this compensation estimation unit, is used for Fu Liye to change this time domain compensation signal to produce a preliminary frequency domain compensation signal; And

One correcting unit, be electrically connected to this decision package and this second Fu Li leaf converting unit, be used for according to this preliminary frequency domain compensation signal of this channel estimation value computing producing this frequency domain compensation signal, and use this frequency domain compensation signal to proofread and correct these and change signals to produce this output signal.

5, pulse noise suppression apparatus as claimed in claim 4, it is characterized in that, wherein this compensation estimation unit is relatively this time domain error signal and one second critical value, if in a time point, the value of this time domain error signal is greater than this second critical value, then this compensation estimation unit is a value of setting this time domain compensation signal according to the value of this time domain error signal, and if in a time point, the value of this time domain error signal is not more than this second critical value, and then this compensation estimation unit is that the value of setting this time domain compensation signal is zero.

6, pulse noise suppression apparatus as claimed in claim 4 is characterized in that, wherein this correcting unit is to utilize these to change signal to deduct this frequency domain compensation signal to produce this output signal.

7, pulse noise suppression apparatus as claimed in claim 1 is characterized in that, wherein these change modules include:

One channel estimation unit is used for calculating this channel estimation value; And

The first-classization unit is electrically connected to this channel estimation unit, is used for changing signal according to this second frequency-region signals of change such as this channel estimation value to produce these.

8, pulse noise suppression apparatus as claimed in claim 7, it is characterized in that, wherein this channel estimation unit more is electrically connected to this compensating module, this decision package, this decision signal that this channel estimation unit is this output signal of producing according to this compensating module, this decision package produces, with present channel estimation value, upgrade this channel estimation value.

9, pulse noise suppression apparatus as claimed in claim 8, it is characterized in that, this channel estimation unit wherein, each subcarrier is calculated a updating value corresponds to this subcarrier with renewal this channel estimation value, wherein this updating value is that this output signal value that corresponds to this subcarrier multiply by this channel estimation value that corresponds to this subcarrier, again divided by this decision signal value that corresponds to this subcarrier.

10, pulse noise suppression apparatus as claimed in claim 1 is characterized in that, it is to be applied to a digital television system.

11, pulse noise suppression apparatus as claimed in claim 1 is characterized in that, wherein this predetermined value is zero.

12, a kind of impulse noise suppression method that is applied to ofdm system, it is characterized in that, it is applied to an orthogonal FDM communication system, be used for suppressing impulsive noise in one first time-domain signal to produce an output signal, wherein this first time-domain signal is a kind of OFDM time-domain signal, this OFDM time-domain signal can get an OFDM frequency-region signal through conversion, and this OFDM frequency-region signal is made up of a plurality of sub-carrier signal, this first time-domain signal is handled through the pulse noise removing and is obtained one second time-domain signal, and this impulse noise suppression method includes:

(a) if in a time point, the value of this first time-domain signal is greater than one first critical value, then controlling this second time-domain signal makes its absolute value be not more than a predetermined value, and if in a time point, the value of this first time-domain signal is not more than this first critical value, then sets the value of this second time-domain signal according to the value of this first time-domain signal;

(b) Fu Liye changes this second time-domain signal to produce one second frequency-region signal;

(c) according to corresponding to each sub-carrier signal in these second frequency-region signals of change such as a channel estimation value of each sub-carrier channels of this orthogonal FDM communication system to produce the first-classization signal, wherein these change signals are made up of a plurality of equating signal values, and each equating signal value is the corresponding subcarrier of difference;

(d) these are changed signal and carry out decision-making treatment to produce a decision signal, wherein this decision signal is made up of a plurality of decision signal values, and each decision signal value is the corresponding subcarrier of difference; And

(e) detect the pairing time domain compensation signal of residual quantity that these change signal and this decision signal, and proofread and correct these according to the pairing frequency domain compensation signal of this time domain compensation signal and change signal to produce this output signal, wherein this output signal is made up of a plurality of output signal value, and each output signal value is the corresponding subcarrier of difference.

13, impulse noise suppression method as claimed in claim 12 is characterized in that, wherein step (d) is to decode corresponding to these change signal values of a sub-carrier channels, to produce this decision signal value corresponding to this sub-carrier channels according at least one critical value.

14, impulse noise suppression method as claimed in claim 12 is characterized in that, wherein step (d) is according to a given value, to produce this decision signal value corresponding to a sub-carrier channels.

15, impulse noise suppression method as claimed in claim 12 is characterized in that, wherein step (e) includes:

(f) according to this channel estimation value, these change the residual quantity of signal and this decision signal computing, to produce a frequency domain error signal;

(g) reverse Fu Li leaf is changed this frequency domain error signal to produce a time domain error signal;

(h) estimate according to this time domain error signal and a time domain compensation signal;

(i) Fu Liye changes this time domain compensation signal to produce a preliminary frequency domain compensation signal; And

(j) according to this channel estimation value, this preliminary frequency domain compensation signal of computing to be producing this frequency domain compensation signal, and uses this frequency domain compensation signal to proofread and correct these and change signals to produce this output signal.

16, impulse noise suppression method as claimed in claim 15, it is characterized in that, wherein step (h) is relatively this time domain error signal and one second critical value, if in a time point, the value of this time domain error signal is greater than this second critical value, then set the value of this time domain compensation signal, and if the value of this time domain error signal is not more than this second critical value, the value of then setting this time domain compensation signal is zero according to the value of this time domain error signal.

17, impulse noise suppression method as claimed in claim 15 is characterized in that, wherein step (j) is to utilize these to change signal to deduct this frequency domain compensation signal to produce this output signal.

18, impulse noise suppression method as claimed in claim 13 is characterized in that, wherein step (c) includes:

(k) calculate this channel estimation value; And

(1) changes signal according to this second frequency-region signals of change such as this channel estimation value to produce these.

19, impulse noise suppression method as claimed in claim 18, it is characterized in that, wherein after step (e) produces this output signal, step (k) decision signal that to be the output signal that produces according to step (e) produced with step (d), and this present channel estimation value are upgraded this channel estimation value.

20, impulse noise suppression method as claimed in claim 19, it is characterized in that, wherein step (k) is that each subcarrier is calculated a updating value corresponds to this subcarrier with renewal channel estimation value, wherein this updating value is that this output signal value that corresponds to this subcarrier multiply by the channel estimation value that corresponds to this subcarrier, again divided by this decision signal value that corresponds to this subcarrier.

21, impulse noise suppression method as claimed in claim 12 is characterized in that, it is to be applied to a digital television system.

22, impulse noise suppression method as claimed in claim 12 is characterized in that, wherein this predetermined value is zero.

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