CN105337908A - Channel estimation device and method and receiver - Google Patents

Abstract

Embodiments of the invention provide a channel estimation device and method and a receiver. The device comprises: a first estimation unit used for carrying out primary estimation on a channel; a first conversion unit used for carrying out inverse Fourier transform on the primary channel estimation result to obtain a time domain signal; a noise suppression unit used for carrying out noise suppression processing on the time domain signal beyond a preset range, wherein the time domain signals within the preset range comprise a time domain signal with effective power larger than a preset first threshold and a time domain signal with effective power smaller than or equal to the first threshold resulting from noise influence; and a second conversion unit used for carrying out Fourier transform on the time domain signal after the noise suppression processing to obtain channel frequency domain response. Since useful signals which may be deemed as noise by mistake within the preset range are protected from being suppressed, the accuracy of channel estimation can be improved, and thus the system performance can be effectively improved.

Description

Channel estimating apparatus, method and receiver

Technical field

The present invention relates to communication technical field, particularly relate to a kind of channel estimating apparatus, method and receiver.

Background technology

Long Term Evolution (LongTermEvolution, LTE) system is based on OFDM (OrthogonalFrequencyDivisionMultiplexing, and the new generation broadband wireless communication system of multiple-input, multiple-output (Multiple-InputMultiple-Output, MIMO) technology OFDM).In the multicarrier system that the physical layer of LTE system defines, at signal receiving end, the frequency sub-carrier (subcarriers) of reception information distribution under wideband frequency selective channel to each approximate steadily decline is transmitted, avoids the impact of frequency selectivity on the LTE system such as load and covering power performance index.Visible, to the performance of the direct influential system demodulation of accuracy that each sub-carrier channels is estimated.

At present, there is the channel estimation methods under multi-frequency selective channel, wherein, be the characteristic of impulse response according to time domain channel, the method for carrying out noise suppressed in time domain is widely used.First frequency domain ZF (Zero-force, ZF) channel estimating is transformed to time domain and carries out noise suppressed by the method, and then switches back to frequency domain and obtain final channel estimation value.Relative to common ZF channel estimating, systematic function is obviously promoted.

Above it should be noted that, just conveniently to technical scheme of the present invention, clear, complete explanation is carried out to the introduction of technical background, and facilitate the understanding of those skilled in the art to set forth.Only can not think that technique scheme is conventionally known to one of skill in the art because these schemes have carried out setting forth in background technology part of the present invention.

Summary of the invention

When utilizing above-mentioned existing channel estimation methods to carry out channel estimating, at the signal to noise ratio (SignaltoNoiseRatio of signal, SNR) when lower, noise is higher, useful signal may be submerged in ambient noise signal, thus cause useful signal by mistake regard as noise and the situation of carrying out suppressing occurs.In this case, systematic function not only may there is no gain, even may cause the decay of systematic function.

The embodiment of the present invention provides a kind of channel estimating apparatus, method and receiver; not suppressed by the useful signal that may be mistaken as noise within protection preset range; the accuracy of channel estimating can be improved, thus effectively can improve the performance of system.

According to the first aspect of the embodiment of the present invention, provide a kind of channel estimating apparatus, described device comprises: the first estimation unit, and described first estimation unit is used for carrying out according to a preliminary estimate channel; First converter unit, described first converter unit is used for carrying out inverse fourier transform according to channel result according to a preliminary estimate, obtains time-domain signal; Noise suppression unit, described noise suppression unit is used for carrying out noise suppressed process to the time-domain signal outside preset range, wherein, the time-domain signal within described preset range comprises effective power and is greater than the time-domain signal of the first threshold preset and causes effective power to be less than or equal to the time-domain signal of described first threshold due to the impact of noise; Second converter unit, described second converter unit is used for carrying out Fourier transform to the time-domain signal after noise suppressed process, obtains channel frequency domain response.

According to the second aspect of the embodiment of the present invention, provide a kind of receiver, described receiver comprises the channel estimating apparatus according to the first aspect of the embodiment of the present invention.

According to the third aspect of the embodiment of the present invention, provide a kind of channel estimation methods, described method comprises: carry out according to a preliminary estimate channel; Carry out inverse fourier transform according to channel result according to a preliminary estimate, obtain time-domain signal; Noise suppressed process is carried out to the time-domain signal outside preset range, wherein, the time-domain signal within described preset range comprises effective power and is greater than the time-domain signal of the first threshold preset and causes effective power to be less than or equal to the time-domain signal of described first threshold due to the impact of noise; Fourier transform is carried out to the time-domain signal after noise suppressed process, obtains channel frequency domain response.

Beneficial effect of the present invention is: not suppressed by the useful signal that may be mistaken as noise within protection preset range, improves the accuracy of channel estimating, thus effectively raises the performance of system.

With reference to explanation hereinafter and accompanying drawing, disclose in detail particular implementation of the present invention, specifying principle of the present invention can adopted mode.Should be appreciated that, thus embodiments of the present invention are not restricted in scope.In the spirit of claims and the scope of clause, embodiments of the present invention comprise many changes, amendment and are equal to.

The feature described for a kind of execution mode and/or illustrate can use in one or more other execution mode in same or similar mode, combined with the feature in other execution mode, or substitutes the feature in other execution mode.

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

Accompanying drawing explanation

Included accompanying drawing is used to provide the further understanding to the embodiment of the present invention, which constituting a part for specification, for illustrating embodiments of the present invention, and coming together to explain principle of the present invention with text description.Apparently, the accompanying drawing in the following describes is only some embodiments of the present invention, for those of ordinary skill in the art, under the prerequisite not paying creative work, can also obtain other accompanying drawing according to these accompanying drawings.In the accompanying drawings:

Fig. 1 is the structural representation of the channel estimating apparatus of the embodiment of the present invention 1;

Fig. 2 is the flow chart of the channel estimation methods of the embodiment of the present invention 1;

Fig. 3 is the structural representation of the scope determining unit of the embodiment of the present invention 1;

Fig. 4 is the method flow diagram determining the parameter of this preset range according to the effective power of the time-domain signal under this communication mode of the embodiment of the present invention 1;

Fig. 5 is a structural representation of the parameter determination unit of the embodiment of the present invention 1;

Fig. 6 is a method flow diagram of the effective power determination preset range parameter according to this time-domain signal of the embodiment of the present invention 1;

Fig. 7 is the effective power of the time-domain signal of the embodiment of the present invention 1 and the schematic diagram of preset range;

Fig. 8 is another structural representation of the parameter determination unit of the embodiment of the present invention 1;

Fig. 9 is the other method flow chart of the effective power determination preset range parameter according to this time-domain signal of inventive embodiments 1;

Figure 10 is a structural representation of the receiver of the embodiment of the present invention 2;

Figure 11 is a schematic block diagram of the System's composition of the receiver of the embodiment of the present invention 2.

Embodiment

With reference to accompanying drawing, by specification below, aforementioned and further feature of the present invention will become obvious.In the specification and illustrated in the drawings, specifically disclose particular implementation of the present invention, which show the some embodiments that wherein can adopt principle of the present invention, will be appreciated that, the invention is not restricted to described execution mode, on the contrary, the present invention includes the whole amendments fallen in the scope of claims, modification and equivalent.

Embodiment 1

Fig. 1 is the structural representation of the channel estimating apparatus of the embodiment of the present invention 1.As shown in Figure 1, this device 100 comprises: the first estimation unit 101, first converter unit 102, noise suppression unit 103 and the second converter unit 104, wherein,

First estimation unit 101 is for carrying out according to a preliminary estimate channel;

First converter unit 102, for carrying out inverse fourier transform to result according to a preliminary estimate, obtains time-domain signal;

Noise suppression unit 103 is for carrying out noise suppressed process to the time-domain signal outside preset range, wherein, the time-domain signal within this preset range comprises effective power and is greater than the time-domain signal of the first threshold preset and causes effective power to be less than or equal to the time-domain signal of this first threshold due to the impact of noise;

Second converter unit 104, for carrying out Fourier transform to the time-domain signal after noise suppressed process, obtains channel frequency domain response.

Fig. 2 is the flow chart of the channel estimation methods of the embodiment of the present invention 1.As shown in Figure 2, the method comprises:

Step 201: channel is carried out according to a preliminary estimate;

Step 202: carry out inverse fourier transform to channel result according to a preliminary estimate, obtains time-domain signal;

Step 203: noise suppressed process is carried out to the time-domain signal outside preset range, wherein, the time-domain signal within this preset range comprises effective power and is greater than the time-domain signal of the first threshold preset and causes effective power to be less than or equal to the time-domain signal of this first threshold due to the impact of noise;

Step 204: carry out Fourier transform to the time-domain signal after noise suppressed process, obtains channel frequency domain response.

From above-described embodiment, not suppressed by the useful signal that may be mistaken as noise within protection preset range, the accuracy of channel estimating can be improved, thus effectively can improve the performance of system.

In the present embodiment, the first estimation unit 101 carries out preliminary channel estimation based on frequency-region signal.The signal directly received due to the receiving terminal of system is time-domain signal, therefore, needs to carry out Fourier transform processing to this time-domain signal received, to obtain corresponding frequency-region signal.

Like this, channel estimating apparatus 100 also can comprise signal receiving unit and signal processing unit (not shown), and wherein, this signal receiving unit is used for from transmitting terminal Received signal strength; This signal processing unit is used for carrying out Fourier transform processing to the received signal, to obtain corresponding frequency-region signal.

In the present embodiment, signal receiving unit and signal processing unit are selectable unit (SU).Such as, when being applied in receiver by channel estimating apparatus 100, the reception of signal and Fourier transform processing can be realized by the miscellaneous part of receiver.

In the present embodiment, any one method existing can be used to carry out according to a preliminary estimate channel.Below to the present embodiment, exemplary explanation is carried out to the method that channel carries out according to a preliminary estimate.

Such as, ZF (Zero-force, ZF) channel estimation methods can be used to carry out channel according to a preliminary estimate to the frequency-region signal y that the first estimation unit 101 receives.Wherein, suppose that X is the reference signal that receiving terminal is known, so the ZF channel estimation value h of reference signal _zFavailable following formula (1) represents:

$h_{\mathrm{ZF}}=X^{-1}-y={\left[\begin{array}{cccc}{h}_{\mathrm{ZF}}\left(0\right)& H_{\mathrm{ZF}}\left(1\right)& ...& H_{\mathrm{ZF}}(N_c-1)\end{array}\right]}^T\∈C^{N_c\×1}---\left(1\right)$

Wherein, X ^-1represent the inverse matrix of reference signal X, N _csubcarrier number included by the bandwidth of receiver, [.] ^trepresenting matrix matrix transpose operation.

In the present embodiment, as shown in Figure 1, channel estimating apparatus 100 can also comprise interpolating unit 105, wherein, the result of interpolation processing for carrying out interpolation processing to channel result according to a preliminary estimate, and is supplied to the first converter unit 102 and carries out described inverse fourier transform by interpolating unit 105.

In the present embodiment, interpolating unit 105 is selectable unit (SU)s, is indicated by the dashed box in FIG.

By carrying out difference process to result according to a preliminary estimate, channel result according to a preliminary estimate being expanded to continuous signal, the accuracy of channel estimating can be improved further.

In the present embodiment, any one method existing can be used to carry out interpolation processing to channel result according to a preliminary estimate.Such as, at ZF channel estimation value h _zFrear insertion (N _fft-N _cthe vector that) × 1 is long, makes ZF channel estimation value h _zFexpand to N _fft× 1 long vectorial h _iP, the channel estimation vector h so after interpolation processing _iPavailable following formula (2) represents:

$h_{\mathrm{IP}}={\left[\begin{array}{cc}{h}_{\mathrm{ZF}}^T& h_{\mathrm{VCFR}}^T\end{array}\right]}^T\∈C^{N_{\mathrm{fft}}\×1}---\left(2\right)$

Wherein, N _fftbe that the second converter unit 104 carries out counting of Fourier transform, N _csubcarrier number included by the bandwidth of receiver, N _fft>=N _c, represent the vector be inserted into, it is called as pseudo channel frequency domain response (VirtualChannelFrequencyResponse, VCFR).

In the present embodiment, linear mode or nonlinear way can be used to carry out this interpolation processing, and the embodiment of the present invention does not limit the concrete mode of interpolation processing.Below respectively exemplary explanation is carried out to the method utilizing linear mode and nonlinear way to carry out difference process of the present embodiment.

Such as, when using linear mode to carry out interpolation processing, its objective is and make to add pseudo channel frequency domain response h _vCFRafter frequency-domain waveform be continuous print cyclical signal, available following formula (3) represent:

$h_{\mathrm{VCFR}}\left(k\right)=\frac{h_{\mathrm{ZF}}\left(0\right)-h_{\mathrm{ZF}}(N_c-1)}{N_{\mathrm{fft}}-N_c+2}.(k-N_c+2)+h_{\mathrm{ZF}}(N_c-1)---\left(3\right)$

Wherein, h _vCFRk () represents the frequency-region signal at the k place after interpolation processing, k ∈ [N _c, N _fft-1], N _fftfor counting of FFT conversion, N _csubcarrier number included by the bandwidth of receiver.

Such as, when using nonlinear way to carry out interpolation processing, its objective is and make to add pseudo channel frequency domain response h _vCFRafter frequency-domain waveform be level and smooth and continuous print cyclical signal, available following formula (4) represents:

$h_{\mathrm{VCFR}}\left(k\right)=\frac{1}{2}(1+\cos \left(\frac{\mathrm{\π}(k-N_c+1)}{L}\right))\·\mathrm{\θ}\left(\frac{k-N_c+1}{L}\right)\·F\left(k\right)+\frac{1}{2}(1+\cos \frac{\mathrm{\π}(k-N_{\mathrm{fft}})}{L})\·\mathrm{\θ}\left(\frac{k-N_{\mathrm{fft}}}{L}\right)\·G\left(k\right)$

$\mathrm{\θ}\left(t\right)=\left\{\begin{array}{c}1,\left|t\right|\≤1\\ 0,\left|t\right|>1\end{array}\right.---\left(4\right)$

Wherein, h _vCFRk () represents the frequency-region signal at the k place after interpolation processing, k ∈ [N _c, N _fft-1], N _csubcarrier number included by the bandwidth of receiver, N _fftfor counting of Fourier transform, F (k) and G (k) represents ZF channel estimation value h respectively _zFat subcarrier N _cthe tangential line segment at-1 and 0 place, L represents the length of tangential line segment, and 2≤L≤(N _fft-N _c)/2.

Wherein, F (k) and the available following formula of G (k) (5) represent:

F(k)＝(k-N _c+1)a+b

(5)

G(k)＝(k-N _fft)c+d

Wherein, k ∈ [N _c, N _fft-1], N _fftfor counting of FFT conversion, N _csubcarrier number included by the bandwidth of receiver;

Wherein, a, b, c, d can calculate according to following formula (6):

$a=\frac{1}{N_{\mathrm{est}}}\underset{i=N_c-N_{\mathrm{esi}}}{\overset{N_c-1}{\mathrm{\Σ}}}(h_{\mathrm{ZF}}\left(i\right)-h_{\mathrm{ZF}}(i-1)),$

$b=\frac{1}{N_{\mathrm{est}}}\underset{i=N_c-N_{\mathrm{esi}}}{\overset{N_c-1}{\mathrm{\Σ}}}{h}_{\mathrm{ZF}}\left(i\right)+\frac{(N_{\mathrm{est}}-1)}{2}a,---\left(6\right)$

$c=\frac{1}{N_{\mathrm{est}}}\underset{i=0}{\overset{N_{\mathrm{esi}}-1}{\mathrm{\Σ}}}(h_{\mathrm{ZF}}(i+1)-h_{\mathrm{ZF}}\left(i\right)),$

$d=\frac{1}{N_{\mathrm{est}}}\underset{i=0}{\overset{N_{\mathrm{esi}}-1}{\mathrm{\Σ}}}{h}_{\mathrm{ZF}}\left(i\right)\frac{(N_{\mathrm{est}}-1)}{2}c$

Wherein, N _estfor submarginal number of subcarriers, N _csubcarrier number included by the bandwidth of receiver.

In the present embodiment, in acquisition after the result of interpolation processing, any one method existing can be used to carry out inverse fourier transform to the result through interpolation processing, thus obtain time-domain signal.

Such as, invert fast fourier transformation (Inverse-FastFourierTransformation, IFFT) method can be used to carry out inverse fourier transform, obtain the time-domain signal represented with following formula (7):

$g_{\mathrm{IP}}=\frac{1}{N_{\mathrm{fft}}}{F}^H{h}_{\mathrm{IP}}---\left(7\right)$

Wherein, g _iPrepresent the channel impulse response (ChannelImpulseresponse, CIR) without noise suppressed process in time domain, and g _iPmeet $g_{\mathrm{IP}}={\left[\begin{array}{cccc}{g}_{\mathrm{IP}}\left(0\right)& g_{\mathrm{IP}}\left(1\right)& ...& g_{\mathrm{IP}}(N_{\mathrm{fft}}-1)\end{array}\right]}^T\∈C^{N_{\mathrm{fft}}\×1},$ F represents FFT transformation matrix, [.] ^hrepresenting matrix conjugate transposition operation.

In the present embodiment, after acquisition time-domain signal, time-domain signal outside noise suppression unit 103 pairs of preset ranges carries out noise suppressed process, wherein, the time-domain signal within this preset range comprises effective power and is greater than the time-domain signal of the first threshold preset and causes effective power to be less than or equal to the time-domain signal of this first threshold due to the impact of noise.

In the present embodiment, the effective power of time-domain signal refers to that signal transmission is subject to the signal power after noise or the impact of other factors.

In the present embodiment, any one method existing can be used to carry out noise suppressed process to the time-domain signal outside preset range.Such as, following formula (8) can be used to carry out noise suppressed process to time-domain signal:

Wherein, g _nSl () represents the time-domain signal at the l place, position after noise suppressed process, g _iPl () represents the time-domain signal without the l place, position of noise suppressed process, A _iPl () represents the power of the time-domain signal at l place, position, T _nocrepresent first threshold, N _startrepresent the original position of preset range, L _wrepresent the length of preset range, N _fftrepresent counting of Fourier transform, 0≤l≤N _fft-1.

In the present embodiment, due to the random fading of signal or when signal to noise ratio is lower, may occur because the impact of noise causes the power of useful signal lower than T _nocand be mistaken as the situation of noise, by only carrying out noise suppressed process to the time-domain signal outside preset range, the useful signal that may be mistaken as noise within this preset range can be protected not suppressed.

In the present embodiment, channel estimating apparatus 100 can also comprise scope determining unit 106, wherein, scope determining unit 106 selects communication mode for the time delay according to this time-domain signal obtained through inverse fourier transform, determine the parameter of this preset range, wherein, the parameter of this preset range comprises the original position of this preset range and the length of this preset range.

In the present embodiment, scope determining unit 106 is selectable unit (SU)s, is indicated by the dashed box in FIG.

In the present embodiment, scope determining unit 106 can select communication mode to use any one method existing to determine the parameter of this preset range according to the time delay of this time-domain signal.Below to the structure of the scope determining unit 106 of the present embodiment and determine that the method for parameter of this preset range carries out exemplary explanation.

Fig. 3 is the structural representation of the scope determining unit of the present embodiment.As shown in Figure 3, scope determining unit 106 comprises the second estimation unit 301, mode selecting unit 302 and parameter determination unit 303, wherein,

Second estimation unit 301 is for carrying out the estimation of delay spread according to the multidiameter delay of this time-domain signal;

Mode selecting unit 302, for selecting corresponding communication mode according to the delay spread estimated, obtains the time-domain signal under this communication mode;

Parameter determination unit 303 is for determining the parameter of this preset range according to the effective power of the time-domain signal under this communication mode.

Fig. 4 is the method flow diagram determining the parameter of this preset range according to the effective power of the time-domain signal under this communication mode of the present embodiment.As shown in Figure 4, the method comprises:

Step 401: the estimation carrying out delay spread according to the multidiameter delay of this time-domain signal;

Step 402: the delay spread according to estimating selects corresponding communication mode, obtains the time-domain signal under this communication mode;

Step 403: the parameter determining this preset range according to the effective power of the time-domain signal under this communication mode.

In the present embodiment, any one method existing can be used according to the multidiameter delay of this time-domain signal to carry out the estimation of delay spread.Below exemplary explanation is carried out to the method for estimation that the multidiameter delay according to this time-domain signal of the present embodiment carries out delay spread.

Such as, the estimation of delay spread can be carried out based on the mode of delay spread definition.

Suppose that the quantity of faded multi-path is M, wherein, obtain the highest time delay multipath of the individual signal strength signal intensity of M ' by any one method existing, and M '≤M.Such as, the time delay multipath that the individual signal strength signal intensity of M ' is the highest use characteristic value can be decomposed the method for (EigenvalueDecomposition, EVD) or is obtained by the method that setting threshold value carries out screening.

According to the definition of delay spread, delay spread τ _rmsavailable following formula (9) represents:

${\mathrm{\τ}}_{\mathrm{rms}}=\sqrt{\frac{\underset{m=0}{\overset{M^{\′}-1}{\mathrm{\Σ}}}{({{\mathrm{\τ}}^{\′}}_m-\stackrel{\‾}{\mathrm{\τ}})}^2{\left|{{\mathrm{\γ}}^{\′}}_m\right|}^2}{\underset{m=0}{\overset{M^{\′}-1}{\mathrm{\Σ}}}{\left|{{\mathrm{\γ}}^{\′}}_m\right|}^2}}---\left(9\right)$

Wherein, τ ' _mwith γ ' _mrepresent time delay value and the range value of m faded multi-path, represent time delay average, m=0,1 ..., M '.

Further, time delay average wherein available following formula (10) represents:

$\stackrel{\‾}{\mathrm{\τ}}=\sqrt{\frac{\underset{m=0}{\overset{M^{\′}-1}{\mathrm{\Σ}}}{{\mathrm{\τ}}^{\′}}_m{\left|{{\mathrm{\γ}}^{\′}}_m\right|}^2}{\underset{m=0}{\overset{M^{\′}-1}{\mathrm{\Σ}}}{\left|{{\mathrm{\γ}}^{\′}}_m\right|}^2}}---\left(10\right)$

Wherein, τ ' _m, γ ' _mand τ _m, γ _mdo not need equal.

Such as, the estimation of delay spread can also be carried out based on the mode of minimal time delay.

Equally, suppose that the quantity of faded multi-path is M, wherein, obtain the highest time delay multipath of the individual signal strength signal intensity of M ' by any one method existing, and M '≤M.In addition, suppose that every bar multipath is by the arrangement of time delay ascending order, namely available following formula (11) represents:

τ' ₀≤τ' ₁≤...≤τ' _M'-1(11)

Wherein, τ ' _m'-1represent the time delay value of M '-1 faded multi-path.

Suppose delay spread τ _rmsequal with maximum delay, thus obtain the delay spread τ that available following formula (12) represents _rms:

τ _rms＝τ' _M'-1(12)

In the present embodiment, after obtaining the delay spread estimated, corresponding communication mode can be selected according to the delay spread of this estimation, obtain the time-domain signal under this communication mode.Wherein, the communication mode that any one method choice existing can be used corresponding to delay spread.Such as, the method by tabling look-up carries out the transmission mode that the different transmission channel model of Selection utilization represents.

Table 1 is the form of the communication mode corresponding with the delay spread estimated of the present embodiment.As shown in table 1, corresponding to the delay spread of certain scope, there is corresponding communication mode.Such as, when the delay spread estimated is 0.5 μ s, then corresponding EVA communication mode is selected.

EPA, EVA and ETU in table 1 are at 3GPP standard TS36.101[3] and TS36.104[4] the middle widely used in receivers transmission channel model defined, but the embodiment of the present invention is not limited to this three kinds of transmission channel models.In addition, the scope corresponding to the delay spread of each communication mode in table 1 sets according to actual needs, and the embodiment of the present invention is not limited to the concrete restriction for delay spread in table 1.

Table 1

Delay spread τ rms(μs)	0～0.1	0.1～1	>1
				Transmission channel model	EPA	EVA	ETU

In the present embodiment, after have selected corresponding transmission channel model, due to the time delay that each transmission channel model is corresponding and amplitude be known, in conjunction with formula (2) above, obtain the time-domain signal corresponding with this transmission channel model represented with following formula (13):

$g_{\mathrm{IP}}^{\det }\left(l\right)=g_{\mathrm{ZF}}^{\det }\left(l\right)+g_{\mathrm{VCFR}}^{\det }\left(l\right)---\left(13\right)$

Wherein, represent the time-domain signal at the position l place corresponding with this transmission channel model, with following formula (14) can be utilized to calculate:

$g_{\mathrm{ZF}}^{\det }\left(l\right)=\frac{1}{N_{\mathrm{fft}}}\underset{m=0}{\overset{M-1}{\mathrm{\Σ}}}{\mathrm{\γ}}_m^{\det }\frac{1-e^{j2\mathrm{\π}({\mathrm{\Δf\τ}}_m^{\det }-l/N_{\mathrm{fft}})N_c}}{1-e^{j2\mathrm{\π}}({\mathrm{\Δf\τ}}_m^{\det }-l/N_{\mathrm{fft}})}$

$g_{\mathrm{VCFR}}^{\det }\left(l\right)=\frac{1}{N_{\mathrm{fft}}}\underset{k=0}{\overset{N_{\mathrm{fft}}-N_c-1}{\mathrm{\Σ}}}{e}^{-j2\mathrm{\πl}(k+N_c)/N_{\mathrm{fft}}}\·h_{\mathrm{VCFR}}^{\det }\left(k\right)---\left(14\right)$

Wherein, with the time delay and amplitude that this transmission channel model is corresponding respectively, k ∈ [N _c, N _fft-1], N _fftfor counting of FFT conversion, N _csubcarrier number included by the bandwidth of receiver, Δ f represents the spacing of each subcarrier, and M is the quantity of faded multi-path, represent the frequency-region signal at the k place through difference process that this transmission channel model is corresponding.

Obtaining the time-domain signal corresponding with transmission mode afterwards, the effective power of this time-domain signal can be obtained according to any one method existing.Such as, following formula (15) can be utilized to calculate:

$A_{\mathrm{IP}}^{\det }\left(l\right)=20\·{\log }_{10}\left|g_{\mathrm{IP}}^{\det }\left(l\right)\right|---\left(15\right)$

Wherein, represent the time-domain signal at the position l place corresponding with this transmission channel model, represent time-domain signal effective power.

In the present embodiment, after obtaining the time-domain signal under this communication mode, parameter determination unit 303 is according to the parameter of the effective power determination preset range of this time-domain signal.Wherein, any one method existing can be used according to the parameter of the effective power determination preset range of this time-domain signal.Below to the structure of the parameter determination unit 303 of the present embodiment and determine that the method for preset range parameter carries out exemplary explanation.

Fig. 5 is a structural representation of the parameter determination unit of the present embodiment.As shown in Figure 5, parameter determination unit 303 comprises the first determining unit 501 and the second determining unit 502, wherein,

First determining unit 501 will be for meeting the original position of position as this preset range of following condition: this time-domain signal is more than or equal in the effective power of this position the Second Threshold that presets and is less than this Second Threshold in the effective power of the next position of this position, and, at this position and the next position, the effective power of this time-domain signal is the variation tendency of decline, wherein, this Second Threshold is less than described first threshold;

Second determining unit 502 is for determining the length of this preset range according to this original position.

Fig. 6 is a method flow diagram of the effective power determination preset range parameter according to this time-domain signal of the present embodiment.As shown in Figure 6, the method comprises:

Step 601: will the original position of position as this preset range of following condition be met: this time-domain signal is more than or equal in the effective power of this position the Second Threshold that presets and is less than this Second Threshold in the effective power of the next position of this position, and, at this position and the next position, the effective power of this time-domain signal is the variation tendency of decline, wherein, this Second Threshold is less than described first threshold;

Step 602: the length determining this preset range according to this original position.

In the present embodiment, any one method existing can be used to determine original position and the length of this preset range.Such as, the original position N of this preset range _startcan obtain according to following method:

Wherein, represent time-domain signal effective power, $\mathrm{\β}\left(l\right)=A_{\mathrm{IP}}^{\det }(l+1)-A_{\mathrm{IP}}^{\det }\left(l\right),$ It represents effective power curve in the slope value of l point, T _startfor the Second Threshold preset, this Second Threshold can set according to actual needs, and this Second Threshold is less than first threshold.

Obtaining the original position N of this preset range _startafterwards, the length L of this preset range _wcan obtain according to following method:

Wherein, N _fftrepresent counting of Fourier transform.

Fig. 7 is the effective power of the time-domain signal of the present embodiment and the schematic diagram of preset range.As shown in Figure 7, from original position N _startthis preset range of Range Representation in the dotted line frame started, namely carries out noise suppressed process to the time-domain signal outside this dotted line frame.

In the present embodiment, parameter determination unit 303 can also have other structures, and it determines that preset range parameter also can adopt other method.Below to another structure of the parameter determination unit of the present embodiment with determine that the other method of preset range parameter carries out exemplary explanation.

Fig. 8 is another structural representation of the parameter determination unit of the present embodiment.As shown in Figure 8, parameter determination unit 303 comprises the 3rd determining unit 801 and the 4th determining unit 802, wherein,

3rd determining unit 801 is for determining the original position of this preset range according to the duration of the delay spread estimated and an OFDM symbol;

4th determining unit 802 is for using the length of the distance of this original position and initial point as this preset range.

Fig. 9 is the other method flow chart of the effective power determination preset range parameter according to this time-domain signal of the present embodiment.As shown in Figure 9, the method comprises:

Step 901: the original position determining this preset range according to the delay spread of estimation and the duration of an OFDM symbol;

Step 902: using the length of the distance of this original position and initial point as this preset range.

In the present embodiment, any one method existing can be used to determine the original position of this preset range.Such as, the original position N of this preset range _startfollowing formula (16) can be utilized to obtain:

Wherein, t _durationrepresent the duration of OFDM (OrthogonalFrequencyDivisionMultiplexing, an OFDM) symbol, τ _rmsrepresent delay spread, N _fftrepresent counting of Fourier transform.

At the original position N with the method determination preset range _startafter, can by this original position N _startwith the distance of the initial point length L as this preset range _w.

In the present embodiment, after the time-domain signal outside noise suppression unit 103 pairs of preset ranges carries out noise suppressed process, the time-domain signal after the second converter unit 104 pairs noise suppressed process carries out Fourier transform, obtains channel frequency domain response.

In the present embodiment, any one method existing can be used to carry out Fourier transform to the time-domain signal after noise suppressed process.Such as, fast fourier transform (FastFourierTransformation, FFT) method can be used to carry out Fourier transform to the time-domain signal after noise suppressed process, the available following formula of result (17) of acquisition represents:

h _NS＝Fg _NS(17)

Wherein, h _nSrepresent channel frequency response, $g_{\mathrm{NS}}={\left[\begin{array}{cccc}{g}_{\mathrm{NS}}\left(0\right)& g_{\mathrm{NS}}\left(1\right)& ...& g_{\mathrm{NS}}(N_{\mathrm{fft}}-1)\end{array}\right]}^T\∈C^{N_{\mathrm{fft}}\×1},$ F represents fourier transform matrix, N _fftrepresent counting of Fourier transform.

Obtaining channel frequency response h _nS, after namely obtaining the result of channel estimating, by this channel frequency response h _nSbe input to for carrying out the demodulation of signal in the demodulating equipment 203 of Fig. 2, thus obtain the Received signal strength after demodulation.

From above-described embodiment, not suppressed by the useful signal that may be mistaken as noise within protection preset range, the accuracy of channel estimating can be improved, thus effectively can improve the performance of system.

Embodiment 2

The embodiment of the present invention also provides a kind of receiver.So that the channel estimating apparatus 100 of embodiment 1 is applied to Frequency Division Duplexing (FDD) (FrequencyDivisionDuplexing in LTE system, FDD) scene in the receiver under pattern is that example is described, wherein the reception of signal and Fourier transform processing are completed by receiver, but the embodiment of the present invention is not limited to be applied in this scene.

Figure 10 is a structural representation of the receiver of the present embodiment.Wherein, this receiver comprises Fourier transform device 1001, channel estimating apparatus 1002 and demodulating equipment 1003, and channel estimating apparatus 1002 has the 26S Proteasome Structure and Function identical with the channel estimating apparatus 100 in Fig. 1.As shown in Figure 10, the time-domain signal received is input in Fourier transform device 1001 and carries out FFT process, and the frequency-region signal y obtained through FFT process is input in channel estimating apparatus 1002, channel estimating apparatus 1002 carries out channel estimating based on frequency-region signal y, and by the result h of channel estimating _nSbe input in demodulating equipment 203, demodulating equipment 203 is according to the result h of channel estimating _nScarry out the demodulation of signal, thus obtain the Received signal strength after demodulation.

In the present embodiment, the frequency-region signal y obtained through FFT process can represent with following formula (18):

$y=h^{T}X+n\∈C^{1\×N_c}---\left(18\right)$

Wherein, represent that diagonal element is the diagonal matrix of load information, for channel frequency domain response (ChannelFrequencyResponse, CFR), for average is the white Gaussian noise of 0.[.] ^trepresenting matrix matrix transpose operation, N _csubcarrier number included by the bandwidth of receiver.

Figure 11 is a schematic block diagram of the System's composition of the receiver 1100 of the embodiment of the present invention 2.As shown in figure 11, receiver 1100 can comprise central processing unit 1101 and memory 1102; Memory 1102 is coupled to central processing unit 1101.This figure is exemplary; The structure of other types can also be used, supplement or replace this structure, to realize telecommunications functions or other functions.

As shown in figure 11, this receiver 1100 can also comprise: communication module 1103, input unit 1104, display 1105, power supply 1106.

In one embodiment, the function of channel estimating apparatus can be integrated in central processing unit 1101.Wherein, central processing unit 1101 can be configured to: carry out according to a preliminary estimate channel; Inverse fourier transform is carried out to channel result according to a preliminary estimate, obtains time-domain signal; Noise suppressed process is carried out to the time-domain signal outside preset range, wherein, the time-domain signal within described preset range comprises effective power and is greater than the time-domain signal of the first threshold preset and causes effective power to be less than or equal to the time-domain signal of described first threshold due to the impact of noise; Fourier transform is carried out to the time-domain signal after noise suppressed process, obtains channel frequency domain response.

Wherein, central processing unit 1101 can also be configured to: the time delay according to the described time-domain signal obtained through inverse fourier transform selects communication mode, determine the parameter of described preset range, wherein, the parameter of described preset range comprises the original position of described preset range and the length of described preset range.

Wherein, the described time delay according to described time-domain signal is selected communication mode thus is determined the parameter of preset range, comprising: the estimation carrying out delay spread according to the multidiameter delay of described time-domain signal; Delay spread according to estimating selects corresponding communication mode, obtains the time-domain signal under described communication mode; The parameter of described preset range is determined according to the effective power of the time-domain signal under described communication mode.

Wherein, the power of the time-domain signal of described basis under described communication mode is determined to comprise the parameter of described preset range; The original position of position as described preset range of following condition will be met: described time-domain signal is more than or equal in the effective power of described position the Second Threshold that presets and is less than described Second Threshold in the effective power of the next position of described position, and, at described position and the next position, the effective power of described time-domain signal is the variation tendency of decline, wherein, described Second Threshold is less than described first threshold; The length of described preset range is determined according to described original position.

Wherein, the time-domain signal of described basis under described communication mode determines the parameter of described preset range, also can comprise: the original position determining described preset range according to the delay spread of estimation and the duration of an OFDM symbol; Using the length of the distance of described original position and initial point as described preset range.

Wherein, central processing unit 1101 can also be configured to: carry out interpolation processing to described channel result according to a preliminary estimate, and carry out described inverse fourier transform according to the result of interpolation processing.

In another embodiment, channel estimating apparatus can with central processing unit 1101 separate configuration, such as channel estimating apparatus can be configured to the chip be connected with central processing unit 1101, be realized the function of channel estimating apparatus by the control of central processing unit.

Receiver 1100 is also not necessary to all parts of comprising shown in Figure 11 in the present embodiment

As shown in figure 11, central processing unit 1101, sometimes also referred to as controller or operational controls, can comprise microprocessor or other processor devices and/or logic device, and central processing unit 1101 receives and inputs and control the operation of all parts of receiver 1100.

Memory 1102 can be such as one or more of in buffer, flash memory, hard disk driver, removable medium, volatile memory, nonvolatile memory or other appropriate device.The above-mentioned information relevant with failure can be stored, execution program for information about can be stored in addition.And central processing unit 1101 can perform this program that this memory 1102 stores, to realize information storage or process etc.The function of miscellaneous part and existing similar, repeats no more herein.Each parts of receiver 1100 can be realized by specialized hardware, firmware, software or its combination, and do not depart from scope of the present invention.

From above-described embodiment, not suppressed by the useful signal that may be mistaken as noise within protection preset range, the accuracy of channel estimating can be improved, thus effectively can improve the performance of system.

Embodiment 3

The embodiment of the present invention also provides a kind of channel estimation methods, and it corresponds to the channel estimating apparatus of embodiment 1, and this channel estimation methods can see the Fig. 2 in embodiment 1.As shown in Figure 2, the method comprises:

Step 201: channel is carried out according to a preliminary estimate;

Step 202: carry out inverse fourier transform to channel result according to a preliminary estimate, obtains time-domain signal;

Step 203: noise suppressed process is carried out to the time-domain signal outside preset range, wherein, the time-domain signal within this preset range comprises effective power and is greater than the time-domain signal of the first threshold preset and causes effective power to be less than or equal to the time-domain signal of this first threshold due to the impact of noise;

Step 204: carry out Fourier transform to the time-domain signal after noise suppressed process, obtains channel frequency domain response.

In the present embodiment, method according to a preliminary estimate carried out to channel, channel result is according to a preliminary estimate carried out to the method for inverse fourier transform, determine the method for the parameter of preset range, the time-domain signal outside preset range carried out to the method for noise suppressed process and the time-domain signal after noise suppressed process is carried out to the method for Fourier transform identical with the record in embodiment 1, no longer repeat herein.

From above-described embodiment, not suppressed by the useful signal that may be mistaken as noise within protection preset range, the accuracy of channel estimating can be improved, thus effectively can improve the performance of system.

The embodiment of the present invention also provides a kind of computer-readable program, and wherein when performing described program in channel estimating apparatus or receiver, described program makes computer in described channel estimating apparatus or receiver, perform channel estimation methods described in embodiment 3.

The embodiment of the present invention also provides a kind of storage medium storing computer-readable program, and wherein said computer-readable program makes computer in channel estimating apparatus or receiver, perform channel estimation methods described in embodiment 3.

Apparatus and method more than the present invention can by hardware implementing, also can by combination of hardware software simulating.The present invention relates to such computer-readable program, when this program is performed by logical block, this logical block can be made to realize device mentioned above or component parts, or make this logical block realize various method mentioned above or step.The invention still further relates to the storage medium for storing above program, as hard disk, disk, CD, DVD, flash memory etc.

More than in conjunction with concrete execution mode, invention has been described, but it will be apparent to those skilled in the art that these descriptions are all exemplary, is not limiting the scope of the invention.Those skilled in the art can make various variants and modifications according to spirit of the present invention and principle to the present invention, and these variants and modifications also within the scope of the invention.

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

Remarks 1, a kind of channel estimating apparatus, described device comprises:

First estimation unit, described first estimation unit is used for carrying out according to a preliminary estimate channel;

First converter unit, described first converter unit is used for carrying out inverse fourier transform to channel result according to a preliminary estimate, obtains time-domain signal;

Noise suppression unit, described noise suppression unit is used for carrying out noise suppressed process to the time-domain signal outside preset range, wherein, the time-domain signal within described preset range comprises effective power and is greater than the time-domain signal of the first threshold preset and causes effective power to be less than or equal to the time-domain signal of described first threshold due to the impact of noise;

Second converter unit, described second converter unit is used for carrying out Fourier transform to the time-domain signal after noise suppressed process, obtains channel frequency domain response.

Remarks 2, device according to remarks 1, wherein, described device also comprises:

Scope determining unit, described scope determining unit is used for selecting communication mode according to the time delay of the described time-domain signal obtained through inverse fourier transform, determine the parameter of described preset range, wherein, the parameter of described preset range comprises the original position of described preset range and the length of described preset range.

Remarks 3, device according to remarks 2, wherein, described scope determining unit comprises:

Second estimation unit, described second estimation unit is used for the estimation carrying out delay spread according to the multidiameter delay of described time-domain signal;

Mode selecting unit, the delay spread that described mode selecting unit is used for according to estimating selects corresponding communication mode, obtains the time-domain signal under described communication mode;

Parameter determination unit, described parameter determination unit is used for the parameter determining described preset range according to the effective power of the time-domain signal under described communication mode.

Remarks 4, device according to remarks 3, wherein, described parameter determination unit comprises;

First determining unit, described first determining unit is used for meeting the original position of position as described preset range of following condition: described time-domain signal is more than or equal in the effective power of described position the Second Threshold that presets and is less than described Second Threshold in the effective power of the next position of described position, and, at described position and the next position, the effective power of described time-domain signal is the variation tendency of decline, wherein, described Second Threshold is less than described first threshold;

Second determining unit, described second determining unit is used for the length determining described preset range according to described original position.

Remarks 5, device according to remarks 3, wherein, described parameter determination unit comprises:

3rd determining unit, described 3rd determining unit is used for the original position determining described preset range according to the delay spread of estimation and the duration of an OFDM symbol;

4th determining unit, shown 4th determining unit is used for the length of the distance of described original position and initial point as described preset range.

Remarks 6, device according to remarks 1, wherein, described noise suppression unit utilizes following formula (1) to carry out noise suppressed process:

$g_{\mathrm{NS}}\left(l\right)=\left\{\begin{array}{c}{g}_{\mathrm{IP}}\left(l\right),\mathrm{if}(A_{\mathrm{IP}}\left(l\right)>T_{\mathrm{noc}})\mathrm{OR}\left[(0\≤l\≤N_{\mathrm{start}})\mathrm{AND}(N_{\mathrm{fft}}-(L_w-N_{\mathrm{start}})\≤l\≤N_{\mathrm{fft}})\right]\\ 0,\mathrm{otherwise}\end{array}\right.---\left(1\right)$

Wherein, g _nSl () represents the time-domain signal at the l place, position after noise suppressed process, g _iPl () represents the time-domain signal without the l place, position of noise suppressed process, A _iPl () represents the power of the time-domain signal at l place, position, T _nocrepresent first threshold, N _startrepresent the original position of preset range, L _wrepresent the length of preset range, N _fftrepresent counting of Fourier transform, 0≤l≤N _fft-1.

Remarks 7, device according to remarks 1, wherein, described device also comprises:

Interpolating unit, described interpolating unit is used for carrying out interpolation processing to described channel result according to a preliminary estimate, and the result of interpolation processing is supplied to described first converter unit and carries out described inverse fourier transform.

Remarks 8, a kind of receiver, described receiver comprises the channel estimating apparatus according to remarks 1.

Remarks 9, a kind of channel estimation methods, described method comprises:

Channel is carried out according to a preliminary estimate;

Inverse fourier transform is carried out to channel result according to a preliminary estimate, obtains time-domain signal;

Noise suppressed process is carried out to the time-domain signal outside preset range, wherein, the time-domain signal within described preset range comprises effective power and is greater than the time-domain signal of the first threshold preset and causes effective power to be less than or equal to the time-domain signal of described first threshold due to the impact of noise;

Fourier transform is carried out to the time-domain signal after noise suppressed process, obtains channel frequency domain response.

Remarks 10, method according to remarks 9, wherein, described method also comprises:

Time delay according to the described time-domain signal obtained through inverse fourier transform selects communication mode, and determine the parameter of described preset range, wherein, the parameter of described preset range comprises the original position of described preset range and the length of described preset range.

Remarks 11, method according to remarks 10, wherein, the described time delay according to described time-domain signal is selected communication mode thus is determined the parameter of preset range, comprising:

The estimation of delay spread is carried out according to the multidiameter delay of described time-domain signal;

Delay spread according to estimating selects corresponding communication mode, obtains the time-domain signal under described communication mode;

The parameter of described preset range is determined according to the effective power of the time-domain signal under described communication mode.

Remarks 12, method according to remarks 11, wherein, the power of the time-domain signal of described basis under described communication mode is determined to comprise the parameter of described preset range;

The original position of position as described preset range of following condition will be met: described time-domain signal is more than or equal in the effective power of described position the Second Threshold that presets and is less than described Second Threshold in the effective power of the next position of described position, and, at described position and the next position, the effective power of described time-domain signal is the variation tendency of decline, wherein, described Second Threshold is less than described first threshold;

The length of described preset range is determined according to described original position.

Remarks 13, method according to remarks 11, wherein, the time-domain signal of described basis under described communication mode determines the parameter of described preset range, comprising:

The original position of described preset range is determined according to the delay spread of estimation and the duration of an OFDM symbol;

Using the length of the distance of described original position and initial point as described preset range.

Remarks 14, method according to remarks 9, wherein, utilize following formula (1) to carry out described noise suppressed process:

$g_{\mathrm{NS}}\left(l\right)=\left\{\begin{array}{c}{g}_{\mathrm{IP}}\left(l\right),\mathrm{if}(A_{\mathrm{IP}}\left(l\right)>T_{\mathrm{noc}})\mathrm{OR}\left[(0\≤l\≤N_{\mathrm{start}})\mathrm{AND}(N_{\mathrm{fft}}-(L_w-N_{\mathrm{start}})\≤l\≤N_{\mathrm{fft}})\right]\\ 0,\mathrm{otherwise}\end{array}\right.---\left(1\right)$

Wherein, g _nSl () represents the time-domain signal at the l place, position after noise suppressed process, g _iPl () represents the time-domain signal without the l place, position of noise suppressed process, A _iPl () represents the power of the time-domain signal at l place, position, T _nocrepresent first threshold, N _startrepresent the original position of preset range, L _wrepresent the length of preset range, N _fftrepresent counting of Fourier transform, 0≤l≤N _fft-1.

Remarks 15, method according to remarks 9, wherein, described method also comprises:

Interpolation processing is carried out to described channel result according to a preliminary estimate, and carries out described inverse fourier transform according to the result of interpolation processing.

Claims (10)

1. a channel estimating apparatus, described device comprises:

First estimation unit, described first estimation unit is used for carrying out according to a preliminary estimate channel;

First converter unit, described first converter unit is used for carrying out inverse fourier transform to channel result according to a preliminary estimate, obtains time-domain signal;

Noise suppression unit, described noise suppression unit is used for carrying out noise suppressed process to the time-domain signal outside preset range, wherein, the time-domain signal within described preset range comprises effective power and is greater than the time-domain signal of the first threshold preset and causes effective power to be less than or equal to the time-domain signal of described first threshold due to the impact of noise;

Second converter unit, described second converter unit is used for carrying out Fourier transform to the time-domain signal after noise suppressed process, obtains channel frequency domain response.

2. device according to claim 1, wherein, described device also comprises:

Scope determining unit, described scope determining unit is used for selecting communication mode according to the time delay of the described time-domain signal obtained through inverse fourier transform, determine the parameter of described preset range, wherein, the parameter of described preset range comprises the original position of described preset range and the length of described preset range.

3. device according to claim 2, wherein, described scope determining unit comprises:

Second estimation unit, described second estimation unit is used for the estimation carrying out delay spread according to the multidiameter delay of described time-domain signal;

Mode selecting unit, the delay spread that described mode selecting unit is used for according to estimating selects corresponding communication mode, obtains the time-domain signal under described communication mode;

Parameter determination unit, described parameter determination unit is used for the parameter determining described preset range according to the effective power of the time-domain signal under described communication mode.

4. device according to claim 3, wherein, described parameter determination unit comprises;

First determining unit, described first determining unit is used for meeting the original position of position as described preset range of following condition: described time-domain signal is more than or equal in the effective power of described position the Second Threshold that presets and is less than described Second Threshold in the effective power of the next position of described position, and, at described position and the next position, the effective power of described time-domain signal is the variation tendency of decline, wherein, described Second Threshold is less than described first threshold;

Second determining unit, described second determining unit is used for the length determining described preset range according to described original position.

5. device according to claim 3, wherein, described parameter determination unit comprises:

3rd determining unit, described 3rd determining unit is used for the original position determining described preset range according to the delay spread of estimation and the duration of an OFDM symbol;

4th determining unit, shown 4th determining unit is used for the length of the distance of described original position and initial point as described preset range.

6. device according to claim 1, wherein, described noise suppression unit utilizes following formula (1) to carry out noise suppressed process:

$g_{\mathrm{NS}}\left(l\right)=\left\{\begin{array}{c}{g}_{\mathrm{IP}}\left(l\right),\mathrm{if}(A_{\mathrm{IP}}\left(l\right)>T_{\mathrm{noc}})\mathrm{OR}\left[(0\≤l\≤N_{\mathrm{start}})\mathrm{AND}(N_{\mathrm{fft}}-(L_w-N_{\mathrm{start}})\≤l\≤N_{\mathrm{fft}})\right]\\ 0,\mathrm{otherwise}\end{array}\right.---\left(1\right)$

Wherein, g _nSl () represents the time-domain signal at the l place, position after noise suppressed process, g _iPl () represents the time-domain signal without the l place, position of noise suppressed process, A _iPl () represents the power of the time-domain signal at l place, position, T _nocrepresent first threshold, N _startrepresent the original position of preset range, L _wrepresent the length of preset range, N _fftrepresent counting of Fourier transform, 0≤l≤N _fft-1.

7. device according to claim 1, wherein, described device also comprises:

Interpolating unit, described interpolating unit is used for carrying out interpolation processing to described channel result according to a preliminary estimate, and the result of interpolation processing is supplied to described first converter unit and carries out described inverse fourier transform.

8. a receiver, described receiver comprises channel estimating apparatus according to claim 1.

9. a channel estimation methods, described method comprises:

Channel is carried out according to a preliminary estimate;

Inverse fourier transform is carried out to channel result according to a preliminary estimate, obtains time-domain signal;

Noise suppressed process is carried out to the time-domain signal outside preset range, wherein, the time-domain signal within described preset range comprises effective power and is greater than the time-domain signal of the first threshold preset and causes effective power to be less than or equal to the time-domain signal of described first threshold due to the impact of noise;

Fourier transform is carried out to the time-domain signal after noise suppressed process, obtains channel frequency domain response.

10. method according to claim 9, wherein, described method also comprises:

Time delay according to the described time-domain signal obtained through inverse fourier transform selects communication mode, and determine the parameter of described preset range, wherein, the parameter of described preset range comprises the original position of described preset range and the length of described preset range.