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

Abstract

Embodiments of the present invention provide a channel estimation device, method, and receiver, wherein the device includes: a first estimation unit that performs preliminary channel estimation; a first transformation unit that performs Fourier inverse transform on the result of the preliminary channel estimation to obtain Time-domain signal: the noise suppression unit performs noise suppression processing on time-domain signals outside the predetermined range, wherein the time-domain signals within the predetermined range include time-domain signals whose effective power is greater than a preset first threshold and due to noise The influence of the influence results in a time-domain signal whose effective power is less than or equal to the first threshold; the second transform unit performs Fourier transform on the time-domain signal after noise suppression processing to obtain a channel frequency-domain response. By protecting useful signals that may be mistaken for noise within a predetermined range from being suppressed, the accuracy of channel estimation can be improved, thereby effectively improving system performance.

Description

Channel estimation device, method and receiver

technical field

The present invention relates to the technical field of communication, and in particular to a channel estimation device, method and receiver.

Background technique

The Long Term Evolution (LTE) system is a new generation of broadband wireless communication system based on Orthogonal Frequency Division Multiplexing (OFDM) and Multiple-Input Multiple-Output (MIMO) technologies. In the multi-carrier system defined by the physical layer of the LTE system, at the signal receiving end, the received information under the wideband frequency-selective channel is allocated to frequency subcarriers (subcarriers) with approximately smooth fading for transmission, which avoids the impact of frequency selectivity on The impact of LTE system performance indicators such as load and coverage capabilities. It can be seen that the accuracy of channel estimation for each subcarrier directly affects the performance of system demodulation.

At present, there are various channel estimation methods under frequency selective channels, among which, according to the characteristic of the time domain channel as an impulse response, the method of noise suppression in the time domain has been widely used. In this method, the zero-force (ZF) channel estimation in the frequency domain is firstly transformed into the time domain for noise suppression, and then transformed back to the frequency domain to obtain the final channel estimation value. Compared with ordinary ZF channel estimation, the system performance is obviously improved.

It should be noted that the above introduction of the technical background is only for the convenience of a clear and complete description of the technical solution of the present invention, and for the convenience of understanding by those skilled in the art. It cannot be considered that the above technical solutions are known to those skilled in the art just because these solutions are described in the background of the present invention.

Contents of the invention

When using the above-mentioned existing channel estimation methods for channel estimation, when the signal-to-noise ratio (Signal to Noise Ratio, SNR) of the signal is low and the noise is high, the useful signal may be submerged in the background noise signal, resulting in useful A situation arises where a signal is falsely identified as noise and suppressed. In this case, not only may no gain be obtained in system performance, but it may even lead to attenuation of system performance.

Embodiments of the present invention provide a channel estimation device, method, and receiver, which can improve the accuracy of channel estimation by protecting useful signals that may be mistaken for noise within a predetermined range from being suppressed, thereby effectively improving the system performance. performance.

According to the first aspect of the embodiments of the present invention, there is provided a channel estimation device, the device includes: a first estimation unit, the first estimation unit is used for preliminary channel estimation; a first transformation unit, the first The transformation unit is used to perform Fourier inverse transform according to the result of preliminary channel estimation to obtain a time-domain signal; the noise suppression unit is used to perform noise suppression processing on time-domain signals outside a predetermined range, wherein the predetermined The time-domain signals within the range include time-domain signals whose effective power is greater than a preset first threshold and time-domain signals whose effective power is less than or equal to the first threshold due to the influence of noise; the second transformation unit, the The second transformation unit is configured to perform Fourier transformation on the time-domain signal after noise suppression processing to obtain a channel frequency-domain response.

According to a second aspect of the embodiments of the present invention, a receiver is provided, and the receiver includes the channel estimation device according to the first aspect of the embodiments of the present invention.

According to the third aspect of the embodiments of the present invention, there is provided a channel estimation method, the method comprising: performing preliminary channel estimation; performing inverse Fourier transform according to the results of the preliminary channel estimation to obtain time-domain signals; The time-domain signal is subjected to noise suppression processing, wherein the time-domain signal within the predetermined range includes a time-domain signal whose effective power is greater than a preset first threshold and whose effective power is less than or equal to the first preset threshold due to the influence of noise. The time-domain signal of the threshold value; the Fourier transform is performed on the time-domain signal after the noise suppression processing to obtain the channel frequency-domain response.

The beneficial effect of the present invention is that the accuracy of channel estimation is improved by protecting useful signals that may be mistaken for noise within a predetermined range from being suppressed, thereby effectively improving system performance.

With reference to the following description and accompanying drawings, there are disclosed in detail specific embodiments of the invention, indicating the manner in which the principles of the invention may be employed. It should be understood that embodiments of the invention are not limited thereby in scope. Embodiments of the invention encompass many changes, modifications and equivalents within the spirit and scope of the appended claims.

Features described and/or illustrated with respect to one embodiment can be used in the same or similar manner in one or more other embodiments, in combination with, or instead of features in other embodiments .

It should be emphasized that the term "comprising/comprising" when used herein refers to the presence of a feature, integer, step or component, but does not exclude the presence or addition of one or more other features, integers, steps or components.

Description of drawings

The included drawings are used to provide further understanding of the embodiments of the present invention, and constitute a part of the specification, are used to illustrate the implementation mode of the present invention, and together with the text description, explain the principle of the present invention. Apparently, the drawings in the following description are only some embodiments of the present invention, and those skilled in the art can obtain other drawings according to these drawings without any creative effort. In the attached picture:

FIG. 1 is a schematic structural diagram of a channel estimation device according to Embodiment 1 of the present invention;

FIG. 2 is a flowchart of a channel estimation method according to Embodiment 1 of the present invention;

FIG. 3 is a schematic structural diagram of a range determination unit in Embodiment 1 of the present invention;

4 is a flowchart of a method for determining parameters in the predetermined range according to the effective power of the time-domain signal in the propagation mode according to Embodiment 1 of the present invention;

5 is a schematic structural diagram of a parameter determination unit in Embodiment 1 of the present invention;

FIG. 6 is a flow chart of a method for determining parameters in a predetermined range according to the effective power of the time-domain signal according to Embodiment 1 of the present invention;

FIG. 7 is a schematic diagram of effective power and a predetermined range of a time-domain signal according to Embodiment 1 of the present invention;

FIG. 8 is another structural schematic diagram of the parameter determination unit in Embodiment 1 of the present invention;

Fig. 9 is a flow chart of another method for determining parameters in a predetermined range according to the effective power of the time-domain signal according to Embodiment 1 of the invention;

FIG. 10 is a schematic structural diagram of a receiver according to Embodiment 2 of the present invention;

Fig. 11 is a schematic block diagram showing the system configuration of a receiver according to Embodiment 2 of the present invention.

detailed description

The foregoing and other features of the invention will become apparent from the following description, taken with reference to the accompanying drawings. In the specification and drawings, specific embodiments of the invention are disclosed, which illustrate some embodiments in which the principles of the invention may be employed. It is to be understood that the invention is not limited to the described embodiments, but rather, the invention The invention includes all modifications, variations and equivalents that come within the scope of the appended claims.

Example 1

FIG. 1 is a schematic structural diagram of a channel estimation device according to Embodiment 1 of the present invention. As shown in FIG. 1, the device 100 includes: a first estimation unit 101, a first transformation unit 102, a noise suppression unit 103, and a second transformation unit 104, wherein,

The first estimating unit 101 is used to perform preliminary estimation on the channel;

The first transformation unit 102 is configured to perform inverse Fourier transformation on the result of the preliminary estimation to obtain a time-domain signal;

The noise suppression unit 103 is configured to perform noise suppression processing on time-domain signals outside the predetermined range, wherein the time-domain signals within the predetermined range include time-domain signals whose effective power is greater than a preset first threshold and noise due to affecting time-domain signals that result in an effective power less than or equal to the first threshold;

The second transformation unit 104 is configured to perform Fourier transformation on the time-domain signal after the noise suppression processing to obtain a channel frequency-domain response.

FIG. 2 is a flow chart of the channel estimation method in Embodiment 1 of the present invention. As shown in Figure 2, the method includes:

Step 201: Preliminary estimation of the channel;

Step 202: performing inverse Fourier transform on the result of preliminary channel estimation to obtain a time-domain signal;

Step 203: Perform noise suppression processing on the time-domain signals outside the predetermined range, wherein the time-domain signals within the predetermined range include time-domain signals with effective power greater than a preset first threshold and effective power due to the influence of noise. a time-domain signal having a power less than or equal to the first threshold;

Step 204: Perform Fourier transform on the noise-suppressed time-domain signal to obtain a channel frequency-domain response.

It can be seen from the above embodiments that the accuracy of channel estimation can be improved by protecting useful signals that may be mistaken for noise within a predetermined range from being suppressed, thereby effectively improving system performance.

In this embodiment, the first estimation unit 101 performs preliminary channel estimation based on frequency domain signals. Since the signal directly received by the receiving end of the system is a time-domain signal, it is necessary to perform Fourier transform processing on the received time-domain signal to obtain a corresponding frequency-domain signal.

In this way, the channel estimation device 100 may also include a signal receiving unit and a signal processing unit (not shown in the figure), wherein the signal receiving unit is used to receive a signal from the transmitting end; the signal processing unit is used to process the received signal Fourier transform processing to obtain the corresponding frequency domain signal.

In this embodiment, the signal receiving unit and the signal processing unit are optional components. For example, when the channel estimation apparatus 100 is applied to a receiver, signal reception and Fourier transform processing can be implemented by other components of the receiver.

In this embodiment, any existing method may be used to initially estimate the channel. The method for initially estimating the channel in this embodiment will be exemplarily described below.

For example, a zero-force (Zero-force, ZF) channel estimation method may be used to perform preliminary channel estimation on the frequency domain signal y received by the first estimation unit 101 . Among them, assuming that X is a known reference signal at the receiving end, then the ZF channel estimation value h _ZF of the reference signal can be expressed by the following formula (1):

${\mathrm{<span\; class="notranslate">\; h</span>}}_{\mathrm{<span\; class="notranslate">\; ZF</span>}}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; x</span>}}^{<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; the\; y</span>}<span\; class="notranslate">\; =</span>{\left[\begin{array}{cccc}{\mathrm{<span\; class="notranslate">\; h</span>}}_{\mathrm{<span\; class="notranslate">\; ZF</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 0</span>}<span\; class="notranslate">\; )</span>& {\mathrm{<span\; class="notranslate">\; h</span>}}_{\mathrm{<span\; class="notranslate">\; ZF</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; )</span>& <span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span>& {\mathrm{<span\; class="notranslate">\; h</span>}}_{\mathrm{<span\; class="notranslate">\; ZF</span>}}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; N</span>}}_{\mathrm{<span\; class="notranslate">\; c</span>}}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; )</span>\end{array}\right]}^{\mathrm{<span\; class="notranslate">\; T</span>}}<span\; class="notranslate">\; \&Element;</span>{\mathrm{<span\; class="notranslate">\; C</span>}}^{{\mathrm{<span\; class="notranslate">\; N</span>}}_{\mathrm{<span\; class="notranslate">\; c</span>}}<span\; class="notranslate">\; \&times;</span>\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; )</span>$

Among them, X ^-1 represents the inverse matrix of the reference signal X, N _c is the number of subcarriers included in the bandwidth of the receiver, and [.] ^T represents the matrix transposition operation.

In this embodiment, as shown in FIG. 1 , the channel estimation apparatus 100 may further include an interpolation unit 105, wherein the interpolation unit 105 is configured to perform interpolation processing on the result of preliminary channel estimation, and provide the result of the interpolation processing to the first The transform unit 102 performs the inverse Fourier transform.

In this embodiment, the interpolation unit 105 is an optional component, which is represented by a dashed box in FIG. 1 .

The accuracy of the channel estimation can be further improved by extending the result of the preliminary estimation of the channel into a continuous signal by performing difference processing on the result of the preliminary estimation.

In this embodiment, any existing method may be used to perform interpolation processing on the result of preliminary channel estimation. For example, insert a (N _fft -N _c )×1-long vector after the ZF channel estimate h _ZF to make the ZF channel estimate h _ZF expand to a N _fft ×1-long vector h _IP , then the interpolated The channel estimation vector h _IP can be expressed by the following formula (2):

${\mathrm{<span\; class="notranslate">\; h</span>}}_{\mathrm{<span\; class="notranslate">\; IP</span>}}<span\; class="notranslate">\; =</span>{\left[\begin{array}{cc}{\mathrm{<span\; class="notranslate">\; h</span>}}_{\mathrm{<span\; class="notranslate">\; ZF</span>}}^{\mathrm{<span\; class="notranslate">\; T</span>}}& {\mathrm{<span\; class="notranslate">\; h</span>}}_{\mathrm{<span\; class="notranslate">\; VCFR</span>}}^{\mathrm{<span\; class="notranslate">\; T</span>}}\end{array}\right]}^{\mathrm{<span\; class="notranslate">\; T</span>}}<span\; class="notranslate">\; \&Element;</span>{\mathrm{<span\; class="notranslate">\; C</span>}}^{{\mathrm{<span\; class="notranslate">\; N</span>}}_{\mathrm{<span\; class="notranslate">\; fft</span>}}<span\; class="notranslate">\; \&times;</span>\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 2</span>}<span\; class="notranslate">\; )</span>$

Wherein, N _fft is the number of points for Fourier transform performed by the second transformation unit 104, N _c is the number of subcarriers included in the bandwidth of the receiver, N _fft ≥ N _c , Represents the inserted vector, which is called a Virtual Channel Frequency Response (VirtualChannelFrequencyResponse, VCFR).

In this embodiment, the interpolation processing may be performed in a linear manner or a nonlinear manner, and this embodiment of the present invention does not limit the specific manner of the interpolation processing. The method for performing difference processing in a linear manner and in a nonlinear manner in this embodiment will be exemplarily described below.

For example, when using a linear method for interpolation processing, the purpose is to make the frequency domain waveform after adding the virtual channel frequency domain response h _VCFR a continuous periodic signal, which can be expressed by the following formula (3):

${\mathrm{<span\; class="notranslate">\; h</span>}}_{\mathrm{<span\; class="notranslate">\; VCFR</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; k</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; =</span>\frac{{\mathrm{<span\; class="notranslate">\; h</span>}}_{\mathrm{<span\; class="notranslate">\; ZF</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 0</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; h</span>}}_{\mathrm{<span\; class="notranslate">\; ZF</span>}}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; N</span>}}_{\mathrm{<span\; class="notranslate">\; c</span>}}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; )</span>}{{\mathrm{<span\; class="notranslate">\; N</span>}}_{\mathrm{<span\; class="notranslate">\; fft</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; N</span>}}_{\mathrm{<span\; class="notranslate">\; c</span>}}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; .</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; k</span>}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; N</span>}}_{\mathrm{<span\; class="notranslate">\; c</span>}}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; 2</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; h</span>}}_{\mathrm{<span\; class="notranslate">\; ZF</span>}}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; N</span>}}_{\mathrm{<span\; class="notranslate">\; c</span>}}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 3</span>}<span\; class="notranslate">\; )</span>$

Among them, h _VCFR (k) represents the frequency domain signal at k after interpolation processing, k∈[N _c , N _fft -1], N _fft is the number of FFT transformation points, and N _c is the number of points included in the bandwidth of the receiver The number of subcarriers.

For example, when using a non-linear method for interpolation processing, the purpose is to make the frequency domain waveform after adding the virtual channel frequency domain response h _VCFR a smooth and continuous periodic signal, which can be expressed by the following formula (4):

${\mathrm{<span\; class="notranslate">\; h</span>}}_{\mathrm{<span\; class="notranslate">\; VCFR</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; k</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; 1</span>}}{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; cos</span>}<span\; class="notranslate">\; (</span>\frac{\mathrm{<span\; class="notranslate">\; \&pi;</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; k</span>}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; N</span>}}_{\mathrm{<span\; class="notranslate">\; c</span>}}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; )</span>}{\mathrm{<span\; class="notranslate">\; L</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; )</span><span\; class="notranslate">\; \&CenterDot;</span>\mathrm{<span\; class="notranslate">\; \&theta;</span>}<span\; class="notranslate">\; (</span>\frac{\mathrm{<span\; class="notranslate">\; k</span>}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; N</span>}}_{\mathrm{<span\; class="notranslate">\; c</span>}}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; 1</span>}}{\mathrm{<span\; class="notranslate">\; L</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; \&CenterDot;</span>\mathrm{<span\; class="notranslate">\; f</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; k</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; +</span>\frac{\mathrm{<span\; class="notranslate">\; 1</span>}}{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; cos</span>}\frac{\mathrm{<span\; class="notranslate">\; \&pi;</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; k</span>}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; N</span>}}_{\mathrm{<span\; class="notranslate">\; fft</span>}}<span\; class="notranslate">\; )</span>}{\mathrm{<span\; class="notranslate">\; L</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; \&CenterDot;</span>\mathrm{<span\; class="notranslate">\; \&theta;</span>}<span\; class="notranslate">\; (</span>\frac{\mathrm{<span\; class="notranslate">\; k</span>}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; N</span>}}_{\mathrm{<span\; class="notranslate">\; fft</span>}}}{\mathrm{<span\; class="notranslate">\; L</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; \&Center\; Dot;</span>\mathrm{<span\; class="notranslate">\; G</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; k</span>}<span\; class="notranslate">\; )</span>$

$\mathrm{<span\; class="notranslate">\; \&theta;</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; t</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; =</span>\left\{\begin{array}{c}\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; ,</span><span\; class="notranslate">\; |</span>\mathrm{<span\; class="notranslate">\; t</span>}<span\; class="notranslate">\; |</span><span\; class="notranslate">\; \&le;</span>\mathrm{<span\; class="notranslate">\; 1</span>}\\ \mathrm{<span\; class="notranslate">\; 0</span>}<span\; class="notranslate">\; ,</span><span\; class="notranslate">\; |</span>\mathrm{<span\; class="notranslate">\; t</span>}<span\; class="notranslate">\; |</span><span\; class="notranslate">\; ></span>\mathrm{<span\; class="notranslate">\; 1</span>}\end{array}\right.<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 4</span>}<span\; class="notranslate">\; )</span>$

Among them, h _VCFR (k) represents the frequency domain signal at k after interpolation processing, k∈[N _c , N _fft -1], N _c is the number of subcarriers included in the bandwidth of the receiver, and N _fft is The number of Fourier transform points, F(k) and G(k) represent the tangential line segment of ZF channel estimation value h _ZF at subcarrier N _c -1 and 0 respectively, L represents the length of the tangential line segment, and 2≤L≤ (N _fft -N _c )/2.

Among them, F(k) and G(k) can be expressed by the following formula (5):

F(k)=(kN _c +1)a+b

(5)

G(k)=(kN _fft )c+d

Among them, k∈[N _c ,N _fft -1], N _fft is the number of FFT transformation points, N _c is the number of subcarriers included in the bandwidth of the receiver;

Among them, a, b, c, d can be calculated according to the following formula (6):

$\mathrm{<span\; class="notranslate">\; a</span>}<span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; 1</span>}}{{\mathrm{<span\; class="notranslate">\; N</span>}}_{\mathrm{<span\; class="notranslate">\; est</span>}}}\underset{\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; N</span>}}_{\mathrm{<span\; class="notranslate">\; c</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; N</span>}}_{\mathrm{<span\; class="notranslate">\; esi</span>}}}{\overset{{\mathrm{<span\; class="notranslate">\; N</span>}}_{\mathrm{<span\; class="notranslate">\; c</span>}}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}}{\mathrm{<span\; class="notranslate">\; \&Sigma;</span>}}}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; h</span>}}_{\mathrm{<span\; class="notranslate">\; ZF</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; h</span>}}_{\mathrm{<span\; class="notranslate">\; ZF</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; )</span><span\; class="notranslate">\; ,</span>$

$\mathrm{<span\; class="notranslate">\; b</span>}<span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; 1</span>}}{{\mathrm{<span\; class="notranslate">\; N</span>}}_{\mathrm{<span\; class="notranslate">\; est</span>}}}\underset{\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; N</span>}}_{\mathrm{<span\; class="notranslate">\; c</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; N</span>}}_{\mathrm{<span\; class="notranslate">\; esi</span>}}}{\overset{{\mathrm{<span\; class="notranslate">\; N</span>}}_{\mathrm{<span\; class="notranslate">\; c</span>}}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}}{\mathrm{<span\; class="notranslate">\; \&Sigma;</span>}}}{\mathrm{<span\; class="notranslate">\; h</span>}}_{\mathrm{<span\; class="notranslate">\; ZF</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; +</span>\frac{<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; N</span>}}_{\mathrm{<span\; class="notranslate">\; est</span>}}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; )</span>}{\mathrm{<span\; class="notranslate">\; 2</span>}}\mathrm{<span\; class="notranslate">\; a</span>}<span\; class="notranslate">\; ,</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 6</span>}<span\; class="notranslate">\; )</span>$

$\mathrm{<span\; class="notranslate">\; c</span>}<span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; 1</span>}}{{\mathrm{<span\; class="notranslate">\; N</span>}}_{\mathrm{<span\; class="notranslate">\; est</span>}}}\underset{\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 0</span>}}{\overset{{\mathrm{<span\; class="notranslate">\; N</span>}}_{\mathrm{<span\; class="notranslate">\; esi</span>}}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}}{\mathrm{<span\; class="notranslate">\; \&Sigma;</span>}}}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; h</span>}}_{\mathrm{<span\; class="notranslate">\; ZF</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; h</span>}}_{\mathrm{<span\; class="notranslate">\; ZF</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; )</span><span\; class="notranslate">\; ,</span>$

$\mathrm{<span\; class="notranslate">\; d</span>}<span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; 1</span>}}{{\mathrm{<span\; class="notranslate">\; N</span>}}_{\mathrm{<span\; class="notranslate">\; est</span>}}}\underset{\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 0</span>}}{\overset{{\mathrm{<span\; class="notranslate">\; N</span>}}_{\mathrm{<span\; class="notranslate">\; esi</span>}}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}}{\mathrm{<span\; class="notranslate">\; \&Sigma;</span>}}}{\mathrm{<span\; class="notranslate">\; h</span>}}_{\mathrm{<span\; class="notranslate">\; ZF</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; )</span>\frac{<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; N</span>}}_{\mathrm{<span\; class="notranslate">\; est</span>}}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; )</span>}{\mathrm{<span\; class="notranslate">\; 2</span>}}\mathrm{<span\; class="notranslate">\; c</span>}$

Wherein, N _est is the number of subcarriers close to the edge, and N _c is the number of subcarriers included in the bandwidth of the receiver.

In this embodiment, after the interpolated result is obtained, any existing method may be used to perform inverse Fourier transform on the interpolated result, so as to obtain a time-domain signal.

For example, the Inverse-Fourier Transformation (IFFT) method can be used to perform inverse Fourier transform to obtain the time-domain signal represented by the following formula (7):

${\mathrm{<span\; class="notranslate">\; g</span>}}_{\mathrm{<span\; class="notranslate">\; IP</span>}}<span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; 1</span>}}{{\mathrm{<span\; class="notranslate">\; N</span>}}_{\mathrm{<span\; class="notranslate">\; fft</span>}}}{\mathrm{<span\; class="notranslate">\; f</span>}}^{\mathrm{<span\; class="notranslate">\; h</span>}}{\mathrm{<span\; class="notranslate">\; h</span>}}_{\mathrm{<span\; class="notranslate">\; IP</span>}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 7</span>}<span\; class="notranslate">\; )</span>$

Among them, g _IP represents the channel impulse response (Channel Impulse response, CIR) that has not been processed by noise suppression in the time domain, and g _IP satisfies $g_{\mathrm{IP}}={\left[\begin{array}{cccc}{g}_{\mathrm{IP}}\left(0\right)& g_{\mathrm{IP}}\left(1\right)& ...& g_{\mathrm{IP}}(N_{\mathrm{fft}}-1)\end{array}\right]}^T\&Element;C^{N_{\mathrm{fft}}\&times;1},$ F represents the FFT transformation matrix, and [.] ^H represents the matrix conjugate transpose operation.

In this embodiment, after obtaining the time-domain signal, the noise suppression unit 103 performs noise suppression processing on the time-domain signal outside the predetermined range, wherein the time-domain signal within the predetermined range includes The time-domain signal of the first threshold and the time-domain signal whose effective power is less than or equal to the first threshold due to the influence of noise.

In this embodiment, the effective power of the time-domain signal refers to the signal power after the transmission signal is affected by noise or other factors.

In this embodiment, any existing method may be used to perform noise suppression processing on time-domain signals outside the predetermined range. For example, the following equation (8) can be used for noise suppression processing on the time domain signal:

Among them, g _NS (l) represents the time domain signal at position l after noise suppression processing, g _IP (l) represents the time domain signal at position l without noise suppression processing, A _IP (l) represents the time domain signal at position l The power of the time-domain signal, T _noc represents the first threshold, N _start represents the starting position of the predetermined range, L _w represents the length of the predetermined range, N _fft represents the number of Fourier transform points, 0≤l≤N _fft -1.

In this embodiment, due to the random fading of the signal or when the signal-to-noise ratio is low, it may occur that the power of the useful signal is lower than T _noc due to the influence of the noise and is mistaken for the noise. The time-domain signal is subjected to noise suppression processing, which can protect useful signals that may be mistaken for noise within the predetermined range from being suppressed.

In this embodiment, the channel estimation apparatus 100 may further include a range determination unit 106, wherein the range determination unit 106 is configured to select a propagation mode according to the time delay of the time-domain signal obtained through inverse Fourier transform, and determine the parameters of the predetermined range , wherein the parameters of the predetermined range include the starting position of the predetermined range and the length of the predetermined range.

In this embodiment, the range determination unit 106 is an optional component, which is represented by a dashed box in FIG. 1 .

In this embodiment, the range determining unit 106 may determine the parameters of the predetermined range by using any existing method according to the time-delay selection propagation mode of the time-domain signal. The structure of the range determination unit 106 of this embodiment and the method for determining the parameters of the predetermined range are exemplarily described below.

Fig. 3 is a schematic structural diagram of the range determination unit in this embodiment. As shown in FIG. 3, the range determination unit 106 includes a second estimation unit 301, a mode selection unit 302, and a parameter determination unit 303, wherein,

The second estimating unit 301 is configured to estimate the delay spread according to the multipath delay of the time domain signal;

The mode selection unit 302 is configured to select a corresponding propagation mode according to the estimated delay spread, and obtain a time-domain signal in the propagation mode;

The parameter determining unit 303 is configured to determine the parameters in the predetermined range according to the effective power of the time domain signal in the propagation mode.

Fig. 4 is a flow chart of the method for determining the parameters in the predetermined range according to the effective power of the time-domain signal in the propagation mode in this embodiment. As shown in Figure 4, the method includes:

Step 401: Estimating delay spread according to the multipath delay of the time domain signal;

Step 402: Select a corresponding propagation mode according to the estimated delay spread, and obtain a time-domain signal in the propagation mode;

Step 403: Determine the parameters of the predetermined range according to the effective power of the time-domain signal in the propagation mode.

In this embodiment, any existing method may be used to estimate the delay spread according to the multipath delay of the time domain signal. The method for estimating delay extension according to the multipath delay of the time-domain signal in this embodiment will be exemplarily described below.

For example, the estimation of the delay spread can be performed based on a delay spread definition.

Assume that the number of fading multipaths is M, where M' delay multipaths with the highest signal strength are obtained by any existing method, and M'≤M. For example, the M′ time-delay multipaths with the highest signal strengths can be obtained by using an eigenvalue decomposition (Eigenvalue Decomposition, EVD) method or by setting a threshold value for screening.

According to the definition of delay spread, the delay spread τ _rms can be expressed by the following formula (9):

${\mathrm{<span\; class="notranslate">\; \&tau;</span>}}_{\mathrm{<span\; class="notranslate">\; rms</span>}}<span\; class="notranslate">\; =</span>\sqrt{\frac{\underset{\mathrm{<span\; class="notranslate">\; m</span>}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 0</span>}}{\overset{{\mathrm{<span\; class="notranslate">\; m</span>}}^{<span\; class="notranslate">\; \&prime;</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}}{\mathrm{<span\; class="notranslate">\; \&Sigma;</span>}}}{<span\; class="notranslate">\; (</span>{{\mathrm{<span\; class="notranslate">\; \&tau;</span>}}^{<span\; class="notranslate">\; \&prime;</span>}}_{\mathrm{<span\; class="notranslate">\; m</span>}}<span\; class="notranslate">\; -</span>\stackrel{<span\; class="notranslate">\; \&OverBar;</span>}{\mathrm{<span\; class="notranslate">\; \&tau;</span>}}<span\; class="notranslate">\; )</span>}^{\mathrm{<span\; class="notranslate">\; 2</span>}}{<span\; class="notranslate">\; |</span>{{\mathrm{<span\; class="notranslate">\; \&gamma;</span>}}^{<span\; class="notranslate">\; \&prime;</span>}}_{\mathrm{<span\; class="notranslate">\; m</span>}}<span\; class="notranslate">\; |</span>}^{\mathrm{<span\; class="notranslate">\; 2</span>}}}{\underset{\mathrm{<span\; class="notranslate">\; m</span>}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 0</span>}}{\overset{{\mathrm{<span\; class="notranslate">\; m</span>}}^{<span\; class="notranslate">\; \&prime;</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}}{\mathrm{<span\; class="notranslate">\; \&Sigma;</span>}}}{<span\; class="notranslate">\; |</span>{{\mathrm{<span\; class="notranslate">\; \&gamma;</span>}}^{<span\; class="notranslate">\; \&prime;</span>}}_{\mathrm{<span\; class="notranslate">\; m</span>}}<span\; class="notranslate">\; |</span>}^{\mathrm{<span\; class="notranslate">\; 2</span>}}}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 9</span>}<span\; class="notranslate">\; )</span>$

Among them, τ' _m and γ' _m represent the delay value and amplitude value of the mth fading multipath, Indicates the mean value of time delay, m=0,1,...,M'.

And, the mean delay in which It can be expressed by the following formula (10):

$\stackrel{<span\; class="notranslate">\; \&OverBar;</span>}{\mathrm{<span\; class="notranslate">\; \&tau;</span>}}<span\; class="notranslate">\; =</span>\sqrt{\frac{\underset{\mathrm{<span\; class="notranslate">\; m</span>}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 0</span>}}{\overset{{\mathrm{<span\; class="notranslate">\; m</span>}}^{<span\; class="notranslate">\; \&prime;</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}}{\mathrm{<span\; class="notranslate">\; \&Sigma;</span>}}}{{\mathrm{<span\; class="notranslate">\; \&tau;</span>}}^{<span\; class="notranslate">\; \&prime;</span>}}_{\mathrm{<span\; class="notranslate">\; m</span>}}{<span\; class="notranslate">\; |</span>{{\mathrm{<span\; class="notranslate">\; \&gamma;</span>}}^{<span\; class="notranslate">\; \&prime;</span>}}_{\mathrm{<span\; class="notranslate">\; m</span>}}<span\; class="notranslate">\; |</span>}^{\mathrm{<span\; class="notranslate">\; 2</span>}}}{\underset{\mathrm{<span\; class="notranslate">\; m</span>}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 0</span>}}{\overset{{\mathrm{<span\; class="notranslate">\; m</span>}}^{<span\; class="notranslate">\; \&prime;</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}}{\mathrm{<span\; class="notranslate">\; \&Sigma;</span>}}}{<span\; class="notranslate">\; |</span>{{\mathrm{<span\; class="notranslate">\; \&gamma;</span>}}^{<span\; class="notranslate">\; \&prime;</span>}}_{\mathrm{<span\; class="notranslate">\; m</span>}}<span\; class="notranslate">\; |</span>}^{\mathrm{<span\; class="notranslate">\; 2</span>}}}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 10</span>}<span\; class="notranslate">\; )</span>$

Among them, τ' _m , γ' _m and τ _m , γ _m need not be equal.

For example, the estimation of the delay spread can also be performed based on the minimum delay.

Similarly, it is assumed that the number of fading multipaths is M, wherein M' delay multipaths with the highest signal strength are obtained by any existing method, and M'≤M. In addition, assuming that each multipath is arranged in ascending order of delay, it can be expressed by the following formula (11):

τ' ₀ ≤τ' ₁ ≤...≤τ'_M'-1 (11)

Wherein, τ'_M'-1 represents the time delay value of the M'-1th fading multipath.

Assuming that the delay spread τ _rms is equal to the maximum delay, the delay spread τ _rms which can be expressed by the following equation (12) is obtained:

τ _rms = τ'_M'-1 (12)

In this embodiment, after the estimated delay spread is obtained, a corresponding propagation mode may be selected according to the estimated delay spread, to obtain a time-domain signal in the propagation mode. Wherein, any existing method may be used to select a propagation mode corresponding to the delay extension. For example, the transmission mode represented by different transmission channel models may be selected through a table look-up method.

Table 1 is a table of propagation modes corresponding to estimated delay spreads in this embodiment. As shown in Table 1, corresponding to a certain range of delay spread, there is a corresponding propagation mode. For example, when the estimated delay spread is 0.5 μs, the corresponding EVA propagation mode is selected.

EPA, EVA, and ETU in Table 1 are transmission channel models widely used in receivers defined in 3GPP standards TS36.101 [3] and TS36.104 [4], but embodiments of the present invention are not limited to these three Transport channel model. In addition, the delay extension range corresponding to each propagation mode in Table 1 is set according to actual needs, and the embodiment of the present invention is not limited to the specific limitation on delay extension in Table 1.

Table 1

Delay spread τ _rms (μs) 0～0.1 0.1～1 >1 Transmission Channel Model EPA EVA ETU

In this embodiment, after the corresponding transmission channel model is selected, due to the delay corresponding to each transmission channel model and amplitude is known, combined with the above formula (2), the time domain signal corresponding to the transmission channel model expressed by the following formula (13) is obtained:

${\mathrm{<span\; class="notranslate">\; g</span>}}_{\mathrm{<span\; class="notranslate">\; IP</span>}}^{\mathrm{<span\; class="notranslate">\; det</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; l</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; g</span>}}_{\mathrm{<span\; class="notranslate">\; ZF</span>}}^{\mathrm{<span\; class="notranslate">\; det</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; l</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; g</span>}}_{\mathrm{<span\; class="notranslate">\; VCFR</span>}}^{\mathrm{<span\; class="notranslate">\; det</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; l</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 13</span>}<span\; class="notranslate">\; )</span>$

in, represents the time-domain signal at position l corresponding to the transmission channel model, and It can be calculated using the following formula (14):

${\mathrm{<span\; class="notranslate">\; g</span>}}_{\mathrm{<span\; class="notranslate">\; ZF</span>}}^{\mathrm{<span\; class="notranslate">\; det</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; l</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; 1</span>}}{{\mathrm{<span\; class="notranslate">\; N</span>}}_{\mathrm{<span\; class="notranslate">\; fft</span>}}}\underset{\mathrm{<span\; class="notranslate">\; m</span>}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 0</span>}}{\overset{\mathrm{<span\; class="notranslate">\; m</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}}{\mathrm{<span\; class="notranslate">\; \&Sigma;</span>}}}{\mathrm{<span\; class="notranslate">\; \&gamma;</span>}}_{\mathrm{<span\; class="notranslate">\; m</span>}}^{\mathrm{<span\; class="notranslate">\; det</span>}}\frac{\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; e</span>}}^{\mathrm{<span\; class="notranslate">\; j</span>}\mathrm{<span\; class="notranslate">\; 2</span>}\mathrm{<span\; class="notranslate">\; \&pi;</span>}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; \&Delta;f\&tau;</span>}}_{\mathrm{<span\; class="notranslate">\; m</span>}}^{\mathrm{<span\; class="notranslate">\; det</span>}}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; l</span>}<span\; class="notranslate">\; /</span>{\mathrm{<span\; class="notranslate">\; N</span>}}_{\mathrm{<span\; class="notranslate">\; fft</span>}}<span\; class="notranslate">\; )</span>{\mathrm{<span\; class="notranslate">\; N</span>}}_{\mathrm{<span\; class="notranslate">\; c</span>}}}}{\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; e</span>}}^{\mathrm{<span\; class="notranslate">\; j</span>}\mathrm{<span\; class="notranslate">\; 2</span>}\mathrm{<span\; class="notranslate">\; \&pi;</span>}}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; \&Delta;f\&tau;</span>}}_{\mathrm{<span\; class="notranslate">\; m</span>}}^{\mathrm{<span\; class="notranslate">\; det</span>}}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; l</span>}<span\; class="notranslate">\; /</span>{\mathrm{<span\; class="notranslate">\; N</span>}}_{\mathrm{<span\; class="notranslate">\; fft</span>}}<span\; class="notranslate">\; )</span>}$

${\mathrm{<span\; class="notranslate">\; g</span>}}_{\mathrm{<span\; class="notranslate">\; VCFR</span>}}^{\mathrm{<span\; class="notranslate">\; det</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; l</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; 1</span>}}{{\mathrm{<span\; class="notranslate">\; N</span>}}_{\mathrm{<span\; class="notranslate">\; fft</span>}}}\underset{\mathrm{<span\; class="notranslate">\; k</span>}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 0</span>}}{\overset{{\mathrm{<span\; class="notranslate">\; N</span>}}_{\mathrm{<span\; class="notranslate">\; fft</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; N</span>}}_{\mathrm{<span\; class="notranslate">\; c</span>}}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}}{\mathrm{<span\; class="notranslate">\; \&Sigma;</span>}}}{\mathrm{<span\; class="notranslate">\; e</span>}}^{<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; j</span>}\mathrm{<span\; class="notranslate">\; 2</span>}\mathrm{<span\; class="notranslate">\; \&pi;l</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; k</span>}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; N</span>}}_{\mathrm{<span\; class="notranslate">\; c</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; /</span>{\mathrm{<span\; class="notranslate">\; N</span>}}_{\mathrm{<span\; class="notranslate">\; fft</span>}}}<span\; class="notranslate">\; \&CenterDot;</span>{\mathrm{<span\; class="notranslate">\; h</span>}}_{\mathrm{<span\; class="notranslate">\; VCFR</span>}}^{\mathrm{<span\; class="notranslate">\; det</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; k</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 14</span>}<span\; class="notranslate">\; )</span>$

in, and are the delay and amplitude corresponding to the transmission channel model, k∈[N _c , N _fft -1], N _fft is the number of FFT transformation points, N _c is the number of subcarriers included in the bandwidth of the receiver, Δf represents The distance between each subcarrier, M is the number of fading multipath, Represents the frequency-domain signal at k corresponding to the transmission channel model after difference processing.

After obtaining the time-domain signal corresponding to the transmission mode After that, the effective power of the time-domain signal can be obtained according to any existing method. For example, it can be calculated using the following formula (15):

${\mathrm{<span\; class="notranslate">\; A</span>}}_{\mathrm{<span\; class="notranslate">\; IP</span>}}^{\mathrm{<span\; class="notranslate">\; det</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; l</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 20</span>}<span\; class="notranslate">\; \&CenterDot;</span>{\mathrm{<span\; class="notranslate">\; log</span>}}_{\mathrm{<span\; class="notranslate">\; 10</span>}}<span\; class="notranslate">\; |</span>{\mathrm{<span\; class="notranslate">\; g</span>}}_{\mathrm{<span\; class="notranslate">\; IP</span>}}^{\mathrm{<span\; class="notranslate">\; det</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; l</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; |</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 15</span>}<span\; class="notranslate">\; )</span>$

in, represents the time-domain signal at position l corresponding to the transmission channel model, Represents a time domain signal effective power.

In this embodiment, after obtaining the time-domain signal in the propagation mode, the parameter determination unit 303 determines parameters in a predetermined range according to the effective power of the time-domain signal. Wherein, any existing method may be used to determine parameters in a predetermined range according to the effective power of the time-domain signal. The structure of the parameter determination unit 303 of this embodiment and the method for determining a parameter in a predetermined range are exemplarily described below.

FIG. 5 is a schematic structural diagram of the parameter determination unit of this embodiment. As shown in FIG. 5, the parameter determination unit 303 includes a first determination unit 501 and a second determination unit 502, wherein,

The first determining unit 501 is configured to use a position that satisfies the following condition as the starting position of the predetermined range: the effective power of the time-domain signal at this position is greater than or equal to a preset second threshold and is at the next position of this position The effective power is less than the second threshold, and, at this position and the next position, the effective power of the time domain signal has a downward trend, wherein the second threshold is less than the first threshold;

The second determining unit 502 is configured to determine the length of the predetermined range according to the starting position.

FIG. 6 is a flow chart of a method for determining parameters in a predetermined range according to the effective power of the time-domain signal in this embodiment. As shown in Figure 6, the method includes:

Step 601: Use the position that meets the following conditions as the starting position of the predetermined range: the effective power of the time domain signal at this position is greater than or equal to a preset second threshold and the effective power at the next position of this position is less than the a second threshold, and, at this position and the next position, the effective power of the time domain signal has a downward trend, wherein the second threshold is smaller than the first threshold;

Step 602: Determine the length of the predetermined range according to the starting position.

In this embodiment, any existing method may be used to determine the initial position and length of the predetermined range. For example, the starting position N _start of the predetermined range can be obtained according to the following method:

in, Represents a time domain signal effective power, $\mathrm{\&beta;}\left(l\right)=A_{\mathrm{IP}}^{\det }(l+1)-A_{\mathrm{IP}}^{\det }\left(l\right),$ which represents the active power curve The slope value at the first point, T _start , is a preset second threshold, which can be set according to actual needs, and the second threshold is smaller than the first threshold.

After obtaining the starting position N _start of the predetermined range, the length L _w of the predetermined range can be obtained according to the following method:

Among them, N _fft represents the number of Fourier transform points.

FIG. 7 is a schematic diagram of the effective power and the predetermined range of the time-domain signal in this embodiment. As shown in FIG. 7 , the range within the dotted frame starting from the starting position N _start represents the predetermined range, that is, noise suppression processing is performed on time domain signals outside the dotted frame.

In this embodiment, the parameter determination unit 303 may also have other structures, and it may also use other methods to determine the predetermined range parameters. Another structure of the parameter determination unit of this embodiment and another method for determining a parameter in a predetermined range are exemplarily described below.

Fig. 8 is another structural schematic diagram of the parameter determining unit of this embodiment. As shown in FIG. 8, the parameter determining unit 303 includes a third determining unit 801 and a fourth determining unit 802, wherein,

The third determining unit 801 is configured to determine the starting position of the predetermined range according to the estimated delay spread and the duration of an OFDM symbol;

The fourth determining unit 802 is configured to use the distance between the starting position and the origin as the length of the predetermined range.

Fig. 9 is a flow chart of another method for determining a predetermined range parameter according to the effective power of the time-domain signal in this embodiment. As shown in Figure 9, the method includes:

Step 901: Determine the starting position of the predetermined range according to the estimated delay spread and the duration of an OFDM symbol;

Step 902: Take the distance between the starting position and the origin as the length of the predetermined range.

In this embodiment, any existing method may be used to determine the starting position of the predetermined range. For example, the starting position N _start of the predetermined range can be obtained using the following formula (16):

Wherein, t _duration represents the duration of an Orthogonal Frequency Division Multiplexing (OFDM) symbol, τ _rms represents the delay extension, and N _fft represents the number of Fourier transform points.

After the starting position N _start of the predetermined range is determined by this method, the distance between the starting position N _start and the origin can be taken as the length L _w of the predetermined range.

In this embodiment, after the noise suppression unit 103 performs noise suppression processing on the time domain signal outside the predetermined range, the second transformation unit 104 performs Fourier transform on the noise suppression processed time domain signal to obtain the channel frequency domain response.

In this embodiment, any existing method may be used to perform Fourier transform on the time-domain signal after noise suppression processing. For example, the Fast Fourier Transformation (FFT) method can be used to perform Fourier transform on the time-domain signal after noise suppression processing, and the obtained result can be expressed by the following formula (17):

_hNS = _FgNS (17)

where h _NS represents the channel frequency response, $g_{\mathrm{NS}}={\left[\begin{array}{cccc}{g}_{\mathrm{NS}}\left(0\right)& g_{\mathrm{NS}}\left(1\right)& ...& g_{\mathrm{NS}}(N_{\mathrm{fft}}-1)\end{array}\right]}^T\&Element;C^{N_{\mathrm{fft}}\&times;1},$ F represents the Fourier transform matrix, and N _fft represents the number of Fourier transform points.

After the channel frequency response h _NS is obtained, that is, the channel estimation result is obtained, the channel frequency response h _NS is input to the demodulation device 203 in FIG. 2 for signal demodulation, thereby obtaining the demodulated received Signal.

It can be seen from the above embodiments that the accuracy of channel estimation can be improved by protecting useful signals that may be mistaken for noise within a predetermined range from being suppressed, thereby effectively improving system performance.

Example 2

The embodiment of the present invention also provides a receiver. The scenario where the channel estimation device 100 of Embodiment 1 is applied to a receiver in frequency division duplexing (Frequency Division Duplexing, FDD) mode in an LTE system is used as an example for illustration, wherein the receiving and Fourier transform processing of signals are completed by the receiver, However, the embodiment of the present invention is not limited to be applied in this scenario.

FIG. 10 is a schematic structural diagram of the receiver of this embodiment. Wherein, the receiver includes a Fourier transform device 1001 , a channel estimation device 1002 and a demodulation device 1003 , and the channel estimation device 1002 has the same structure and function as the channel estimation device 100 in FIG. 1 . As shown in Figure 10, the received time-domain signal is input into the Fourier transform device 1001 for FFT processing, and the frequency-domain signal y obtained through FFT processing is input into the channel estimation device 1002, and the channel estimation device 1002 is based on the frequency domain Channel estimation is performed on the signal y, and the channel estimation result h _NS is input to the demodulation device 203, and the demodulation device 203 demodulates the signal according to the channel estimation result h _NS to obtain the demodulated received signal.

In this embodiment, the frequency-domain signal y obtained through FFT processing can be represented by the following formula (18):

$\mathrm{<span\; class="notranslate">\; the\; y</span>}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; h</span>}}^{\mathrm{<span\; class="notranslate">\; T</span>}}\mathrm{<span\; class="notranslate">\; x</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; \&Element;</span>{\mathrm{<span\; class="notranslate">\; C</span>}}^{\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; \&times;</span>{\mathrm{<span\; class="notranslate">\; N</span>}}_{\mathrm{<span\; class="notranslate">\; c</span>}}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 18</span>}<span\; class="notranslate">\; )</span>$

in, Represents a diagonal matrix whose diagonal elements are load information, For the channel frequency domain response (ChannelFrequencyResponse, CFR), Gaussian white noise with a mean of 0. [.] ^T represents the matrix transposition operation, and N _c is the number of subcarriers included in the bandwidth of the receiver.

FIG. 11 is a schematic block diagram of the system configuration of a receiver 1100 according to Embodiment 2 of the present invention. As shown in FIG. 11 , the receiver 1100 may include a central processing unit 1101 and a memory 1102 ; the memory 1102 is coupled to the central processing unit 1101 . This diagram is exemplary; other types of structures may also be used in addition to or in place of this structure, for telecommunications or other functions.

As shown in FIG. 11 , the receiver 1100 may further include: a communication module 1103 , an input unit 1104 , a display 1105 , and a power supply 1106 .

In one embodiment, the function of the channel estimation device can be integrated into the central processing unit 1101 . Wherein, the central processing unit 1101 may be configured to: perform a preliminary estimation of the channel; perform Fourier inverse transform on the result of the preliminary channel estimation to obtain a time-domain signal; perform noise suppression processing on the time-domain signal outside the predetermined range, wherein the The time-domain signals within the predetermined range include time-domain signals whose effective power is greater than a preset first threshold and time-domain signals whose effective power is less than or equal to the first threshold due to the influence of noise; after noise suppression processing Fourier transform is performed on the time domain signal to obtain the channel frequency domain response.

Wherein, the central processing unit 1101 may also be configured to: select a propagation mode according to the time delay of the time-domain signal obtained through inverse Fourier transform, and determine the parameters of the predetermined range, wherein the parameters of the predetermined range include the The starting position of the predetermined range and the length of the predetermined range.

Wherein, the selection of the propagation mode according to the delay of the time domain signal so as to determine the parameters of the predetermined range includes: estimating the delay spread according to the multipath delay of the time domain signal; A corresponding propagation mode, obtaining a time-domain signal in the propagation mode; determining parameters in the predetermined range according to effective power of the time-domain signal in the propagation mode.

Wherein, the determining the parameters of the predetermined range according to the power of the time domain signal in the propagation mode includes: taking the position satisfying the following condition as the starting position of the predetermined range: the time domain signal is in the The effective power at the position is greater than or equal to a preset second threshold and the effective power at a position next to the position is less than the second threshold, and, at the position and the next position, the time-domain signal The effective powers all have a downward trend, wherein the second threshold is smaller than the first threshold; and the length of the predetermined range is determined according to the starting position.

Wherein, the determining the parameters of the predetermined range according to the time domain signal in the propagation mode may also include: determining the predetermined range according to the estimated delay spread and the duration of an OFDM symbol The starting position of ; the distance between the starting position and the origin is taken as the length of the predetermined range.

Wherein, the central processing unit 1101 may also be configured to: perform interpolation processing on the result of the preliminary channel estimation, and perform the inverse Fourier transform according to the result of the interpolation processing.

In another embodiment, the channel estimation device can be configured separately from the central processor 1101, for example, the channel estimation device can be configured as a chip connected to the central processor 1101, and the function of the channel estimation device can be realized through the control of the central processor.

In this embodiment, the receiver 1100 does not necessarily include all the components shown in FIG. 11

As shown in FIG. 11 , the central processing unit 1101 is sometimes also referred to as a controller or an operating control, and may include a microprocessor or other processor devices and/or logic devices. The central processing unit 1101 receives input and controls various components of the receiver 1100 operation.

The memory 1102 may be, for example, one or more of a cache, a flash memory, a hard drive, a removable medium, a volatile memory, a non-volatile memory, or other suitable devices. The above-mentioned failure-related information may be stored, and a program for executing the related information may also be stored. And the central processing unit 1101 can execute the program stored in the memory 1102 to implement information storage or processing. The functions of other components are similar to those in the prior art, and will not be repeated here. The various components of receiver 1100 may be implemented by dedicated hardware, firmware, software or a combination thereof without departing from the scope of the present invention.

It can be seen from the above embodiments that the accuracy of channel estimation can be improved by protecting useful signals that may be mistaken for noise within a predetermined range from being suppressed, thereby effectively improving system performance.

Example 3

An embodiment of the present invention also provides a channel estimation method, which corresponds to the channel estimation device in Embodiment 1. For the channel estimation method, refer to FIG. 2 in Embodiment 1. As shown in Figure 2, the method includes:

Step 201: Preliminary estimation of the channel;

Step 202: performing inverse Fourier transform on the result of preliminary channel estimation to obtain a time-domain signal;

Step 203: Perform noise suppression processing on the time-domain signals outside the predetermined range, wherein the time-domain signals within the predetermined range include time-domain signals with effective power greater than a preset first threshold and effective power due to the influence of noise. a time-domain signal having a power less than or equal to the first threshold;

Step 204: Perform Fourier transform on the noise-suppressed time-domain signal to obtain a channel frequency-domain response.

In this embodiment, the method of preliminary estimation of the channel, the method of inverse Fourier transform of the result of the preliminary estimation of the channel, the method of determining the parameters of the predetermined range, and the method of performing noise suppression processing on the time domain signals outside the predetermined range And the method of performing Fourier transform on the time-domain signal after noise suppression processing is the same as that described in Embodiment 1, and will not be repeated here.

It can be seen from the above embodiments that the accuracy of channel estimation can be improved by protecting useful signals that may be mistaken for noise within a predetermined range from being suppressed, thereby effectively improving system performance.

An embodiment of the present invention also provides a computer-readable program, wherein when the program is executed in the channel estimation device or receiver, the program causes the computer to execute the program described in Embodiment 3 in the channel estimation device or receiver. channel estimation method.

An embodiment of the present invention also provides a storage medium storing a computer-readable program, wherein the computer-readable program enables a computer to execute the channel estimation method described in Embodiment 3 in a channel estimation device or receiver.

The above devices and methods of the present invention can be implemented by hardware, or by combining hardware and software. The present invention relates to such a computer-readable program that, when the program is executed by a logic component, enables the logic component to realize the above-mentioned device or constituent component, or enables the logic component to realize the above-mentioned various methods or steps. The present invention also relates to storage media for storing the above programs, such as hard disks, magnetic disks, optical disks, DVDs, flash memories, and the like.

The present invention has been described above in conjunction with specific embodiments, but those skilled in the art should be clear that these descriptions are all exemplary and not limiting the protection scope of the present invention. Those skilled in the art can make various variations and modifications to the present invention according to the spirit and principle of the present invention, and these variations and modifications are also within the scope of the present invention.

Regarding the implementation manner comprising the above embodiments, the following additional notes are also disclosed:

Supplementary note 1. A channel estimation device, said device comprising:

a first estimating unit, the first estimating unit is used for preliminary channel estimation;

A first transformation unit, the first transformation unit is configured to perform Fourier inverse transformation on the result of the preliminary channel estimation to obtain a time-domain signal;

A noise suppression unit, the noise suppression unit is configured to perform noise suppression processing on time-domain signals outside a predetermined range, wherein the time-domain signals within the predetermined range include time domain signals with effective power greater than a preset first threshold A domain signal and a time domain signal whose effective power is less than or equal to the first threshold due to the influence of noise;

A second transformation unit, the second transformation unit is configured to perform Fourier transformation on the time-domain signal after the noise suppression processing to obtain a channel frequency-domain response.

Supplement 2. The device according to Supplement 1, wherein the device further includes:

A range determination unit, the range determination unit is configured to select a propagation mode according to the time delay of the time domain signal obtained by inverse Fourier transform, and determine the parameters of the predetermined range, wherein the parameters of the predetermined range include the predetermined The starting position of the range and the length of the predetermined range.

Supplement 3. The device according to Supplement 2, wherein the range determination unit includes:

A second estimating unit, the second estimating unit is configured to estimate delay spread according to the multipath delay of the time domain signal;

A mode selection unit, the mode selection unit is used to select a corresponding propagation mode according to the estimated delay spread, and obtain a time domain signal in the propagation mode;

A parameter determination unit, configured to determine the parameters in the predetermined range according to the effective power of the time domain signal in the propagation mode.

Supplement 4. The device according to Supplement 3, wherein the parameter determination unit includes;

A first determining unit, the first determining unit is configured to use a position satisfying the following condition as the starting position of the predetermined range: the effective power of the time domain signal at the position is greater than or equal to a preset second threshold And the effective power at the position next to the position is less than the second threshold, and at the position and the next position, the effective power of the time-domain signal has a downward trend, wherein the first a second threshold is less than the first threshold;

A second determining unit, configured to determine the length of the predetermined range according to the starting position.

Supplement 5. The device according to Supplement 3, wherein the parameter determination unit includes:

A third determining unit, configured to determine the starting position of the predetermined range according to the estimated delay spread and the duration of an OFDM symbol;

A fourth determining unit, where the fourth determining unit is configured to use the distance between the starting position and the origin as the length of the predetermined range.

Supplement 6. The device according to Supplement 1, wherein the noise suppression unit uses the following formula (1) to perform noise suppression processing:

${\mathrm{<span\; class="notranslate">\; g</span>}}_{\mathrm{<span\; class="notranslate">\; NS</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; l</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; =</span>\left\{\begin{array}{c}{\mathrm{<span\; class="notranslate">\; g</span>}}_{\mathrm{<span\; class="notranslate">\; IP</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; l</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; if</span>}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; A</span>}}_{\mathrm{<span\; class="notranslate">\; IP</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; l</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; ></span>{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; noc</span>}}<span\; class="notranslate">\; )</span>\mathrm{<span\; class="notranslate">\; OR</span>}<span\; class="notranslate">\; [</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 0</span>}<span\; class="notranslate">\; \&le;</span>\mathrm{<span\; class="notranslate">\; l</span>}<span\; class="notranslate">\; \&le;</span>{\mathrm{<span\; class="notranslate">\; N</span>}}_{\mathrm{<span\; class="notranslate">\; start</span>}}<span\; class="notranslate">\; )</span>\mathrm{<span\; class="notranslate">\; AND</span>}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; N</span>}}_{\mathrm{<span\; class="notranslate">\; fft</span>}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; L</span>}}_{\mathrm{<span\; class="notranslate">\; w</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; N</span>}}_{\mathrm{<span\; class="notranslate">\; start</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; \&le;</span>\mathrm{<span\; class="notranslate">\; l</span>}<span\; class="notranslate">\; \&le;</span>{\mathrm{<span\; class="notranslate">\; N</span>}}_{\mathrm{<span\; class="notranslate">\; fft</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; ]</span>\\ \mathrm{<span\; class="notranslate">\; 0</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; otherwise</span>}\end{array}\right.<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; )</span>$

Among them, g _NS (l) represents the time domain signal at position l after noise suppression processing, g _IP (l) represents the time domain signal at position l without noise suppression processing, A _IP (l) represents the time domain signal at position l The power of the time-domain signal, T _noc represents the first threshold, N _start represents the starting position of the predetermined range, L _w represents the length of the predetermined range, N _fft represents the number of Fourier transform points, 0≤l≤N _fft -1.

Supplement 7. The device according to Supplement 1, wherein the device further comprises:

An interpolation unit, configured to perform interpolation processing on the result of the preliminary channel estimation, and provide the result of the interpolation processing to the first transform unit to perform the inverse Fourier transform.

Supplement 8. A receiver, the receiver comprising the channel estimation device according to Supplement 1.

Supplementary Note 9. A channel estimation method, the method comprising:

Make a preliminary estimate of the channel;

Inverse Fourier transform is performed on the result of preliminary channel estimation to obtain a time-domain signal;

performing noise suppression processing on time-domain signals outside the predetermined range, wherein the time-domain signals within the predetermined range include time-domain signals whose effective power is greater than a preset first threshold and whose effective power is less than or a time-domain signal equal to said first threshold;

Perform Fourier transform on the time-domain signal after noise suppression processing to obtain the channel frequency-domain response.

Supplement 10. The method according to Supplement 9, wherein the method further includes:

Select a propagation mode according to the time delay of the time-domain signal obtained through inverse Fourier transform, and determine the parameters of the predetermined range, where the parameters of the predetermined range include the starting position of the predetermined range and the position of the predetermined range length.

Supplement 11. The method according to Supplement 10, wherein the selecting a propagation mode according to the delay of the time-domain signal so as to determine a predetermined range of parameters includes:

Estimating delay spread according to the multipath delay of the time domain signal;

selecting a corresponding propagation mode according to the estimated time delay spread, and obtaining a time-domain signal in the propagation mode;

The parameters of the predetermined range are determined according to the effective power of the time domain signal in the propagation mode.

Supplement 12. The method according to Supplement 11, wherein said determining the parameters of the predetermined range according to the power of the time-domain signal in the propagation mode includes;

A position that satisfies the following conditions is used as the starting position of the predetermined range: the effective power of the time domain signal at the position is greater than or equal to a preset second threshold and the effective power at the position next to the position is less than The second threshold, and, at the position and the next position, the effective power of the time domain signal has a downward trend, wherein the second threshold is smaller than the first threshold;

The length of the predetermined range is determined according to the starting position.

Supplement 13. The method according to Supplement 11, wherein said determining the parameters of the predetermined range according to the time-domain signal in the propagation mode includes:

determining the start position of the predetermined range according to the estimated delay spread and the duration of an OFDM symbol;

The distance between the starting position and the origin is taken as the length of the predetermined range.

Supplement 14. The method according to Supplement 9, wherein the noise suppression process is performed using the following formula (1):

${\mathrm{<span\; class="notranslate">\; g</span>}}_{\mathrm{<span\; class="notranslate">\; NS</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; l</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; =</span>\left\{\begin{array}{c}{\mathrm{<span\; class="notranslate">\; g</span>}}_{\mathrm{<span\; class="notranslate">\; IP</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; l</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; if</span>}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; A</span>}}_{\mathrm{<span\; class="notranslate">\; IP</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; l</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; ></span>{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; noc</span>}}<span\; class="notranslate">\; )</span>\mathrm{<span\; class="notranslate">\; OR</span>}<span\; class="notranslate">\; [</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 0</span>}<span\; class="notranslate">\; \&le;</span>\mathrm{<span\; class="notranslate">\; l</span>}<span\; class="notranslate">\; \&le;</span>{\mathrm{<span\; class="notranslate">\; N</span>}}_{\mathrm{<span\; class="notranslate">\; start</span>}}<span\; class="notranslate">\; )</span>\mathrm{<span\; class="notranslate">\; AND</span>}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; N</span>}}_{\mathrm{<span\; class="notranslate">\; fft</span>}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; L</span>}}_{\mathrm{<span\; class="notranslate">\; w</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; N</span>}}_{\mathrm{<span\; class="notranslate">\; start</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; \&le;</span>\mathrm{<span\; class="notranslate">\; l</span>}<span\; class="notranslate">\; \&le;</span>{\mathrm{<span\; class="notranslate">\; N</span>}}_{\mathrm{<span\; class="notranslate">\; fft</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; ]</span>\\ \mathrm{<span\; class="notranslate">\; 0</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; otherwise</span>}\end{array}\right.<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; )</span>$

Among them, g _NS (l) represents the time domain signal at position l after noise suppression processing, g _IP (l) represents the time domain signal at position l without noise suppression processing, A _IP (l) represents the time domain signal at position l The power of the time-domain signal, T _noc represents the first threshold, N _start represents the starting position of the predetermined range, L _w represents the length of the predetermined range, N _fft represents the number of Fourier transform points, 0≤l≤N _fft -1.

Supplement 15. The method according to Supplement 9, wherein the method further includes:

performing interpolation processing on the result of the preliminary channel estimation, and performing the inverse Fourier transform according to the result of the interpolation processing.

Claims (10)

1. A channel estimation device, said device comprising: a first estimating unit, the first estimating unit is used for preliminary channel estimation; A first transformation unit, the first transformation unit is configured to perform Fourier inverse transformation on the result of the preliminary channel estimation to obtain a time-domain signal; A noise suppression unit, the noise suppression unit is configured to perform noise suppression processing on time-domain signals outside a predetermined range, wherein the time-domain signals within the predetermined range include time domain signals with effective power greater than a preset first threshold A domain signal and a time domain signal whose effective power is less than or equal to the first threshold due to the influence of noise; A second transformation unit, the second transformation unit is configured to perform Fourier transformation on the time-domain signal after the noise suppression processing to obtain a channel frequency-domain response. 2. The device of claim 1, wherein the device further comprises: A range determination unit, the range determination unit is configured to select a propagation mode according to the time delay of the time domain signal obtained by inverse Fourier transform, and determine the parameters of the predetermined range, wherein the parameters of the predetermined range include the predetermined The starting position of the range and the length of the predetermined range. 3. The apparatus according to claim 2, wherein the range determining unit comprises: A second estimating unit, the second estimating unit is configured to estimate delay spread according to the multipath delay of the time domain signal; A mode selection unit, the mode selection unit is used to select a corresponding propagation mode according to the estimated delay spread, and obtain a time domain signal in the propagation mode; A parameter determination unit, configured to determine the parameters in the predetermined range according to the effective power of the time domain signal in the propagation mode. 4. The device according to claim 3, wherein the parameter determination unit comprises; A first determining unit, the first determining unit is configured to use a position satisfying the following condition as the starting position of the predetermined range: the effective power of the time domain signal at the position is greater than or equal to a preset second threshold And the effective power at the position next to the position is less than the second threshold, and at the position and the next position, the effective power of the time-domain signal has a downward trend, wherein the first a second threshold is less than the first threshold; A second determining unit, configured to determine the length of the predetermined range according to the starting position. 5. The device according to claim 3, wherein the parameter determination unit comprises: A third determining unit, configured to determine the starting position of the predetermined range according to the estimated delay spread and the duration of an OFDM symbol; A fourth determining unit, where the fourth determining unit is configured to use the distance between the starting position and the origin as the length of the predetermined range. 6. The device according to claim 1, wherein the noise suppression unit uses the following formula (1) to perform noise suppression processing: ${\mathrm{<span\; class="notranslate">\; g</span>}}_{\mathrm{<span\; class="notranslate">\; NS</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; l</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; =</span>\left\{\begin{array}{c}{\mathrm{<span\; class="notranslate">\; g</span>}}_{\mathrm{<span\; class="notranslate">\; IP</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; l</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; if</span>}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; A</span>}}_{\mathrm{<span\; class="notranslate">\; IP</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; l</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; ></span>{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; noc</span>}}<span\; class="notranslate">\; )</span>\mathrm{<span\; class="notranslate">\; OR</span>}<span\; class="notranslate">\; [</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 0</span>}<span\; class="notranslate">\; \&le;</span>\mathrm{<span\; class="notranslate">\; l</span>}<span\; class="notranslate">\; \&le;</span>{\mathrm{<span\; class="notranslate">\; N</span>}}_{\mathrm{<span\; class="notranslate">\; start</span>}}<span\; class="notranslate">\; )</span>\mathrm{<span\; class="notranslate">\; AND</span>}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; N</span>}}_{\mathrm{<span\; class="notranslate">\; fft</span>}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; L</span>}}_{\mathrm{<span\; class="notranslate">\; w</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; N</span>}}_{\mathrm{<span\; class="notranslate">\; start</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; \&le;</span>\mathrm{<span\; class="notranslate">\; l</span>}<span\; class="notranslate">\; \&le;</span>{\mathrm{<span\; class="notranslate">\; N</span>}}_{\mathrm{<span\; class="notranslate">\; fft</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; ]</span>\\ \mathrm{<span\; class="notranslate">\; 0</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; otherwise</span>}\end{array}\right.<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; )</span>$ Among them, g _NS (l) represents the time domain signal at position l after noise suppression processing, g _IP (l) represents the time domain signal at position l without noise suppression processing, A _IP (l) represents the time domain signal at position l The power of the time-domain signal, T _noc represents the first threshold, N _start represents the starting position of the predetermined range, L _w represents the length of the predetermined range, N _fft represents the number of Fourier transform points, 0≤l≤N _fft -1. 7. The apparatus of claim 1, wherein the apparatus further comprises: An interpolation unit, configured to perform interpolation processing on the result of the preliminary channel estimation, and provide the result of the interpolation processing to the first transform unit to perform the inverse Fourier transform. 8. A receiver comprising the channel estimation device according to claim 1. 9. A channel estimation method, the method comprising: Make a preliminary estimate of the channel; Inverse Fourier transform is performed on the result of preliminary channel estimation to obtain a time-domain signal; performing noise suppression processing on time-domain signals outside the predetermined range, wherein the time-domain signals within the predetermined range include time-domain signals whose effective power is greater than a preset first threshold and whose effective power is less than or a time-domain signal equal to said first threshold; Perform Fourier transform on the time-domain signal after noise suppression processing to obtain the channel frequency-domain response. 10. The method of claim 9, wherein the method further comprises: Select a propagation mode according to the time delay of the time-domain signal obtained through inverse Fourier transform, and determine the parameters of the predetermined range, where the parameters of the predetermined range include the starting position of the predetermined range and the position of the predetermined range length.