CN108075992B - Channel estimation method and device - Google Patents
Channel estimation method and device Download PDFInfo
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- CN108075992B CN108075992B CN201610987356.8A CN201610987356A CN108075992B CN 108075992 B CN108075992 B CN 108075992B CN 201610987356 A CN201610987356 A CN 201610987356A CN 108075992 B CN108075992 B CN 108075992B
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- H04L25/02—Details ; arrangements for supplying electrical power along data transmission lines
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- H04L25/02—Details ; arrangements for supplying electrical power along data transmission lines
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- H04L25/0224—Channel estimation using sounding signals
- H04L25/0228—Channel estimation using sounding signals with direct estimation from sounding signals
- H04L25/023—Channel estimation using sounding signals with direct estimation from sounding signals with extension to other symbols
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Abstract
The invention provides a channel estimation method and a channel estimation device, relates to the technical field of communication, and aims to obtain accurate channel estimation information in narrow-band channel transmission. The channel estimation method of the present invention includes: acquiring a channel estimation matrix of a current subframe; performing frequency domain correlation calculation according to the channel estimation matrix to obtain a frequency domain correlation value of the current subframe; performing time domain correlation calculation according to the channel estimation matrix to obtain a time domain correlation value of the current subframe; determining a frequency domain interpolation filter coefficient according to the frequency domain correlation value, and determining a time domain interpolation filter coefficient according to the time domain correlation value; and determining the channel estimation of the frequency point to be estimated according to the frequency domain interpolation filter coefficient and the time domain interpolation filter coefficient. The invention is mainly used in a narrow-band communication system.
Description
Technical Field
The present invention relates to the field of communications technologies, and in particular, to a channel estimation method and apparatus.
Background
There is a need to acquire channel estimation information in a wireless communication system. In the traditional channel estimation method, a frequency domain interpolation filter coefficient and a time domain interpolation filter coefficient are generated by estimating specific channel time delay expansion and Doppler frequency offset, and then the coefficients are utilized to carry out interpolation filtering on the channel estimation information of the known pilot frequency, so that the channel estimation information of other unknown frequency points is obtained.
The above method is suitable for wideband channel transmission. For Narrow-Band channel transmission such as NB-IOT (Narrow Band Internet of things based on cellular), the traditional channel estimation method cannot obtain accurate channel delay spread and doppler frequency offset. This will result in inaccurate interpolated filter coefficients and thus inaccurate channel estimation information.
Disclosure of Invention
In view of the above, the present invention provides a channel estimation method and apparatus for obtaining accurate channel estimation information in narrowband channel transmission.
To solve the above technical problem, the present invention provides a channel estimation method, including:
acquiring a channel estimation matrix of a current subframe;
performing frequency domain correlation calculation according to the channel estimation matrix to obtain a frequency domain correlation value of the current subframe;
performing time domain correlation calculation according to the channel estimation matrix to obtain a time domain correlation value of the current subframe;
determining a frequency domain interpolation filter coefficient according to the frequency domain correlation value, and determining a time domain interpolation filter coefficient according to the time domain correlation value;
and determining the channel estimation of the frequency point to be estimated according to the frequency domain interpolation filter coefficient and the time domain interpolation filter coefficient.
Wherein, the step of performing frequency domain correlation calculation according to the channel estimation matrix to obtain the frequency domain correlation value of the current subframe includes:
calculating a first correlation value of channel estimation of any two adjacent pilot frequencies in each column of the channel estimation matrix;
and determining the frequency domain correlation value of the current subframe by using the obtained plurality of first correlation values.
Wherein the step of determining the frequency domain correlation value of the current subframe by using the obtained plurality of first correlation values comprises:
and calculating the average value of the obtained plurality of first correlation values, and taking the average value as the frequency domain correlation value.
Wherein, the step of performing time domain correlation calculation according to the channel estimation matrix to obtain the time domain correlation value of the current subframe comprises:
calculating a second correlation value of the channel estimation of any two adjacent pilot frequencies in each row of the channel estimation matrix;
and determining a time domain correlation value of the current subframe by using the obtained plurality of second correlation values.
Wherein the step of determining the frequency domain correlation value of the current subframe by using the obtained plurality of second correlation values comprises:
and calculating the average value of the obtained plurality of second correlation values, and taking the average value as the time domain correlation value.
Wherein the step of determining a frequency domain interpolation filter coefficient according to the frequency domain correlation value comprises:
acquiring N frequency domain correlation threshold values and N-1 frequency domain interpolation coefficients;
comparing the modulus of the frequency domain correlation value with a first frequency domain correlation threshold value and a second frequency domain correlation threshold value which are adjacent in the N frequency domain correlation threshold values respectively;
if the modulus of the frequency domain correlation value is larger than the first frequency domain correlation threshold value and smaller than or equal to the second frequency domain correlation threshold value, taking the frequency domain interpolation coefficient corresponding to the first frequency domain correlation threshold value as the frequency domain interpolation filter coefficient;
wherein N is an integer greater than 2, and the second frequency domain correlation threshold is greater than the first frequency domain correlation threshold.
Wherein the step of determining a time-domain interpolation filter coefficient according to the time-domain correlation value includes:
obtaining M time domain correlation threshold values and M-1 time domain interpolation coefficients;
comparing the modulus of the time domain correlation value with a first time domain correlation threshold value and a second time domain correlation threshold value which are adjacent in the M time domain correlation threshold values respectively;
if the modulus of the time domain correlation value is larger than the first time domain correlation threshold value and smaller than or equal to the second time domain correlation threshold value, taking a time domain interpolation coefficient corresponding to the first time domain correlation threshold value as the time domain interpolation filter coefficient;
wherein M is an integer greater than 2, and the second time domain correlation threshold is greater than the first time domain correlation threshold.
Wherein after the steps of determining a frequency domain interpolation filter coefficient according to the frequency domain correlation value and determining a time domain interpolation filter coefficient according to the time domain correlation value, the method further comprises:
carrying out smooth filtering on the frequency domain correlation value to obtain a smooth frequency domain correlation value;
performing smooth filtering on the time domain correlation value to obtain a smooth time domain correlation value;
the steps of determining a frequency domain interpolation filter coefficient according to the frequency domain correlation value and determining a time domain interpolation filter coefficient according to the time domain correlation value specifically include:
and determining a frequency domain interpolation filter coefficient according to the smooth frequency domain related value, and determining a time domain interpolation filter coefficient according to the smooth time domain related value.
In a second aspect, the present invention provides a channel estimation apparatus, including:
the matrix acquisition module is used for acquiring a channel estimation matrix of a current subframe;
a frequency domain correlation value calculation module, configured to perform frequency domain correlation calculation according to the channel estimation matrix to obtain a frequency domain correlation value of the current subframe;
a time domain correlation value calculation module, configured to perform time domain correlation calculation according to the channel estimation matrix to obtain a time domain correlation value of the current subframe;
the frequency domain interpolation filter coefficient determining module is used for determining a frequency domain interpolation filter coefficient according to the frequency domain related value;
the time domain interpolation filter coefficient determining module is used for determining a time domain interpolation filter coefficient according to the time domain related value;
and the channel estimation module is used for determining the channel estimation of the frequency point to be estimated according to the frequency domain interpolation filter coefficient and the time domain interpolation filter coefficient.
Wherein the frequency domain correlation value calculation module comprises:
the first calculation submodule is used for calculating a first correlation value of channel estimation of any two adjacent pilot frequencies in each column of the channel estimation matrix;
and the first obtaining submodule is used for determining the frequency domain correlation value of the current subframe by using the obtained plurality of first correlation values.
The first obtaining submodule is specifically configured to: and calculating the average value of the obtained plurality of first correlation values, and taking the average value as the frequency domain correlation value.
Wherein the time domain correlation value calculation module comprises:
the second calculation submodule is used for calculating a second correlation value of the channel estimation of any two adjacent pilot frequencies in each row of the channel estimation matrix;
and the second obtaining submodule is used for determining the time domain correlation value of the current subframe by using the obtained plurality of second correlation values.
The second obtaining submodule is specifically configured to calculate an average value of the obtained plurality of second correlation values, and use the average value as the time domain correlation value.
Wherein the frequency domain interpolation filter coefficient determining module comprises:
the first obtaining sub-module is used for obtaining N frequency domain correlation threshold values and N-1 frequency domain interpolation coefficients;
the first comparison sub-module is used for comparing the modulus of the frequency domain correlation value with a first frequency domain correlation threshold value and a second frequency domain correlation threshold value which are adjacent in the N frequency domain correlation threshold values respectively;
a first determining sub-module, configured to, if a modulus of the frequency domain correlation value is greater than the first frequency domain correlation threshold value and less than or equal to the second frequency domain correlation threshold value, use a frequency domain interpolation coefficient corresponding to the first frequency domain correlation threshold value as the frequency domain interpolation filtering coefficient;
wherein N is an integer greater than 2, and the second frequency domain correlation threshold is greater than the first frequency domain correlation threshold.
Wherein the time-domain interpolation filter coefficient determining module comprises:
the second obtaining submodule is used for obtaining M time domain correlation threshold values and M-1 time domain interpolation coefficients;
a second comparing sub-module, configured to compare the modulus of the time domain correlation value with a first time domain correlation threshold and a second time domain correlation threshold that are adjacent to each other in the M time domain correlation thresholds, respectively;
a second determining submodule, configured to, if a modulus of the time domain correlation value is greater than the first time domain correlation threshold value and is less than or equal to the second time domain correlation threshold value, use a time domain interpolation coefficient corresponding to the first time domain correlation threshold value as the time domain interpolation filter coefficient;
wherein M is an integer greater than 2, and the second time domain correlation threshold is greater than the first time domain correlation threshold.
Wherein the apparatus further comprises:
the first smoothing filtering module is used for performing smoothing filtering on the frequency domain correlation value to obtain a smooth frequency domain correlation value;
the second smoothing filtering module is used for performing smoothing filtering on the time domain correlation value to obtain a smooth time domain correlation value;
the frequency domain interpolation filter coefficient determining module is specifically configured to determine a frequency domain interpolation filter coefficient according to the smoothed frequency domain correlation value;
the time domain interpolation filter coefficient determining module is specifically configured to determine a time domain interpolation filter coefficient according to the smoothed time domain correlation value.
The technical scheme of the invention has the following beneficial effects:
in the embodiment of the invention, the frequency domain correlation value and the time domain correlation value are obtained through the frequency domain and time domain correlation calculation, and then the frequency domain interpolation filter coefficient and the time domain interpolation filter coefficient are obtained to complete interpolation filtering, so that the channel estimation information of other unknown frequency points is quickly and accurately obtained, and the defects of inaccurate time delay expansion and Doppler frequency offset estimation caused by too few pilot frequencies under a narrow-band channel in the prior art are overcome. Therefore, the scheme of the embodiment of the invention can obtain accurate channel estimation information in narrow-band channel transmission.
Drawings
Fig. 1 is a flowchart of a channel estimation method according to a first embodiment of the present invention;
FIG. 2 is a flowchart of a channel estimation method according to a second embodiment of the present invention;
fig. 3 is a processing diagram of a channel estimation method according to a second embodiment of the present invention;
fig. 4 is a schematic diagram of a channel estimation apparatus according to a third embodiment of the present invention;
fig. 5 is a structural diagram of a channel estimation device according to a third embodiment of the present invention.
Detailed Description
The following detailed description of embodiments of the present invention will be made with reference to the accompanying drawings and examples. The following examples are intended to illustrate the invention but are not intended to limit the scope of the invention.
Example one
As shown in fig. 1, a channel estimation method according to a first embodiment of the present invention includes:
In the embodiment of the invention, the channel estimation matrix of the current sub-frame is obtained according to the estimation of the pilot frequency of the current sub-frame.
And 102, performing frequency domain correlation calculation according to the channel estimation matrix to obtain a frequency domain correlation value of the current subframe.
In this step, first correlation values of channel estimates of any two adjacent pilots in each column of the channel estimation matrix are calculated, and then frequency domain correlation values of the current subframe are determined by using the obtained plurality of first correlation values. Further, an average value of the obtained plurality of first correlation values is calculated, and the average value is used as the frequency domain correlation value.
And 103, performing time domain correlation calculation according to the channel estimation matrix to obtain a time domain correlation value of the current subframe.
In this step, second correlation values of channel estimates of any two adjacent pilots in each row of the channel estimation matrix are calculated, and then a time domain correlation value of the current subframe is determined by using the obtained plurality of second correlation values. Further, an average value of the obtained plurality of second correlation values is calculated, and the average value is used as the time domain correlation value.
The steps 102 and 103 are not strictly sequential.
And 104, determining a frequency domain interpolation filter coefficient according to the frequency domain correlation value, and determining a time domain interpolation filter coefficient according to the time domain correlation value.
In this step, when determining the frequency domain interpolation filter coefficient, first, N preset frequency domain correlation threshold values and N-1 pre-generated frequency domain interpolation coefficients are obtained. Then, the modulus of the frequency domain correlation value is compared with a first frequency domain correlation threshold value and a second frequency domain correlation threshold value which are adjacent to each other in the N frequency domain correlation threshold values respectively.
If the modulus of the frequency domain correlation value is larger than the first frequency domain correlation threshold value and smaller than or equal to the second frequency domain correlation threshold value, taking the frequency domain interpolation coefficient corresponding to the first frequency domain correlation threshold value as the frequency domain interpolation filter coefficient; wherein N is an integer greater than 2, and the second frequency domain correlation threshold is greater than the first frequency domain correlation threshold.
In this step, when determining the time domain interpolation filter coefficient, M time domain correlation threshold values and M-1 time domain interpolation coefficients that are preset are obtained. Then, the modulus of the time domain correlation value is compared with the adjacent first time domain correlation threshold value and the second time domain correlation threshold value in the M time domain correlation threshold values respectively.
If the modulus of the time domain correlation value is larger than the first time domain correlation threshold value and smaller than or equal to the second time domain correlation threshold value, taking a time domain interpolation coefficient corresponding to the first time domain correlation threshold value as the time domain interpolation filter coefficient; wherein M is an integer greater than 2, and the second time domain correlation threshold is greater than the first time domain correlation threshold.
And 105, determining channel estimation of the frequency point to be estimated according to the frequency domain interpolation filter coefficient and the time domain interpolation filter coefficient.
And performing frequency domain filtering on the channel estimation result of the known pilot frequency in the current subframe by using the frequency domain interpolation filtering coefficient, performing time domain filtering on the frequency domain filtering result by using the time domain interpolation filtering coefficient, and finally obtaining the channel estimation of all the frequency points to be estimated in the current subframe.
Therefore, in the embodiment of the invention, the frequency domain correlation value and the time domain correlation value are obtained through the frequency domain and time domain correlation calculation, and the frequency domain interpolation filter coefficient and the time domain interpolation filter coefficient are further obtained to complete the interpolation filtering, so that the channel estimation information of other unknown frequency points is quickly and accurately obtained, and the defects of inaccurate time delay expansion and Doppler frequency offset estimation caused by too few pilot frequencies under a narrow-band channel in the prior art are avoided. Therefore, the scheme of the embodiment of the invention can obtain accurate channel estimation information in narrow-band channel transmission.
Example two
In the second embodiment of the present invention, an NB-IOT system is taken as an example for description. Fig. 2 is a flowchart of a second embodiment of the present invention, and fig. 3 is a processing diagram of the second embodiment of the present invention. With reference to fig. 2 and fig. 3, a channel estimation method according to a second embodiment of the present invention includes:
Assuming that the channel estimation matrix of the known pilot of the current subframe is:
wherein in the channel estimation matrix, elements
The pilot channel estimation representing the kth subcarrier position in the ith column has a value range of L being 0,1,. cndot.l-1, where K being 0,1,. cndot.k-1, where L is the number of columns of the current subframe and K is the number of pilot points in a column of pilot frequencies in the frequency domain; l, K are each integers greater than 1.
Wherein the first correlation value is calculated according to the following formula (1):
wherein the content of the first and second substances,
denotes a first correlation value, L ═ 0, 1.. gte.l-1, K ═ 0, 1.. gte.k-2.
By performing the above calculation on any two adjacent pilots in each column in the channel estimation matrix, a plurality of first correlation values can be obtained.
Specifically, in this step, an average value of the obtained plurality of first correlation values is calculated according to the following formula (2), and the average value is taken as the frequency domain correlation value:
wherein the content of the first and second substances,
which represents the frequency-domain correlation value(s),
denotes a first correlation value, L ═ 0, 1.. gte.l-1, K ═ 0, 1.. gte.k-2.
And 204, calculating a second correlation value of the channel estimation of any two adjacent pilots in each row of the channel estimation matrix.
Wherein the second correlation value is calculated according to the following formula (3):
wherein the content of the first and second substances,
denotes a second correlation value, L ═ 0, 1.. 3, K ═ 0, 1.. K-1.
By performing the above calculation on any two adjacent pilots in each column in the channel estimation matrix, a plurality of first correlation values can be obtained.
Specifically, in this step, an average value of the obtained plurality of second correlation values is calculated according to the following formula (4), and the average value is taken as the time-domain correlation value.
Wherein the content of the first and second substances,
which represents the value of the time-domain correlation,
denotes a second correlation value, L ═ 0, 1.. gte.l-1, K ═ 0, 1.. gte.k-2.
And step 206, performing smooth filtering on the frequency domain correlation value and the time domain correlation value obtained by the current subframe to respectively obtain a smooth frequency domain correlation value and a smooth time domain correlation value.
Specifically, the frequency domain correlation value is smoothed and filtered according to the following formula (5); the time-domain correlation values are smoothed according to the following equation (6).
Wherein, R ″)FRepresenting the smoothed frequency-domain correlation value of the frequency domain,
representing the frequency domain correlation value of the current sub-frame,
the frequency domain correlation value of the previous sub-frame is represented, and the initial value is 0, α1Representing a first coefficient, which may be preset; r ″)TRepresenting the smoothed time-domain correlation value(s),
represents the time-domain correlation value of the current sub-frame,
the time domain correlation value of the previous sub-frame is represented, and the initial value is 0, α2Indicating a second coefficient, which may be preset α1、α2May be the same or different.
Preferably, the coating is applied, in practical use,
the smooth frequency domain correlation value corresponding to the previous sub-frame can be adopted
The smoothed time domain correlation value corresponding to the previous subframe may be used.
And step 207, determining a frequency domain interpolation filter coefficient according to the frequency domain correlation value.
In this step, N frequency domain correlation threshold values are set
Pre-generating N-1 frequency domain interpolation coefficients
By comparing the frequency domain correlation value obtained in step 206 with the frequency domain correlation threshold, a suitable coefficient is selected from the pre-generated N-1 frequency domain interpolation filter coefficients.
The selection criteria are as follows: and comparing the modulus of the frequency domain correlation value with a first frequency domain correlation threshold value and a second frequency domain correlation threshold value which are adjacent to each other in the N frequency domain correlation threshold values respectively. And if the modulus of the frequency domain correlation value is larger than the first frequency domain correlation threshold value and smaller than or equal to the second frequency domain correlation threshold value, taking the frequency domain interpolation coefficient corresponding to the first frequency domain correlation threshold value as the frequency domain interpolation filtering coefficient.
In particular, if
Then choose the coefficient
Interpolating a filter coefficient for a frequency domain of a current subframe, wherein N is an integer of 2 or more,
representing the modulus of the frequency domain correlation value.
And step 208, determining a time domain interpolation filter coefficient according to the time domain correlation value.
In this step, M time domain correlation thresholds are set
Pre-generating M-1 time-domain interpolation filter coefficients
By comparing the time domain correlation value obtained in step 206 with the time domain correlation threshold, a suitable coefficient is selected from the pre-generated time domain interpolation filter coefficients.
The selection criteria are as follows: comparing the modulus of the time domain correlation value with a first time domain correlation threshold value and a second time domain correlation threshold value which are adjacent in the M time domain correlation threshold values respectively; and if the modulus of the time domain correlation value is larger than the first time domain correlation threshold value and smaller than or equal to the second time domain correlation threshold value, taking a time domain interpolation coefficient corresponding to the first time domain correlation threshold value as the time domain interpolation filter coefficient.
In particular, if
Then choose the coefficient
Is the time domain interpolation filter coefficient of the current sub-frame, M is an integer more than 2,
representing the modulus of the time-domain correlation value.
And 209, determining channel estimation of the frequency point to be estimated according to the frequency domain interpolation filter coefficient and the time domain interpolation filter coefficient.
And performing frequency domain filtering on the channel estimation result of the known pilot frequency in the current subframe by using the frequency domain interpolation filtering coefficient, performing time domain filtering on the frequency domain filtering result by using the time domain interpolation filtering coefficient, and finally obtaining the channel estimation H of all the frequency points to be estimated in the current subframe.
In the above scheme, there is no strict precedence relationship between steps 202 and 203 and steps 204 and 205, and there is no strict precedence relationship between step 207 and step 208.
The technical scheme of the invention is suitable for narrow-band wireless communication systems such as NB-IOT/eMTC and the like.
Therefore, in the scheme of the embodiment of the invention, the proper interpolation filter coefficient is selected from the prestored interpolation filter coefficients through the judgment criterion to carry out channel estimation, so that the defects of time delay expansion and inaccurate Doppler frequency offset estimation caused by too few pilot frequencies in a narrow-band channel in the conventional method are avoided. Therefore, the scheme of the embodiment of the invention can obtain accurate channel estimation information in narrow-band channel transmission. In addition, in the scheme of the embodiment of the invention, the time delay expansion and the Doppler frequency offset do not need to be estimated, and the interpolation filter coefficient does not need to be calculated through the time delay expansion and the Doppler frequency offset, so that the computation load and the complexity are greatly reduced.
EXAMPLE III
As shown in fig. 4, a channel estimation apparatus according to a third embodiment of the present invention includes:
a matrix obtaining module 401, configured to obtain a channel estimation matrix of a current subframe; a frequency domain correlation value calculating module 402, configured to perform frequency domain correlation calculation according to the channel estimation matrix to obtain a frequency domain correlation value of the current subframe; a time domain correlation value calculation module 403, configured to perform time domain correlation calculation according to the channel estimation matrix to obtain a time domain correlation value of the current subframe; a frequency domain interpolation filter coefficient determining module 404, configured to determine a frequency domain interpolation filter coefficient according to the frequency domain correlation value; a time domain interpolation filter coefficient determining module 405, configured to determine a time domain interpolation filter coefficient according to the time domain correlation value; and the channel estimation module 406 is configured to determine channel estimation of the frequency point to be estimated according to the frequency domain interpolation filter coefficient and the time domain interpolation filter coefficient.
Wherein the frequency domain correlation value calculating module 402 comprises:
the first calculation submodule is used for calculating a first correlation value of channel estimation of any two adjacent pilot frequencies in each column of the channel estimation matrix; and the first obtaining submodule is used for determining the frequency domain correlation value of the current subframe by using the obtained plurality of first correlation values.
Specifically, the first obtaining sub-module is specifically configured to: and calculating the average value of the obtained plurality of first correlation values, and taking the average value as the frequency domain correlation value.
Wherein the time domain correlation value calculating module 403 includes:
the second calculation submodule is used for calculating a second correlation value of the channel estimation of any two adjacent pilot frequencies in each row of the channel estimation matrix; and the second obtaining submodule is used for determining the time domain correlation value of the current subframe by using the obtained plurality of second correlation values.
Specifically, the second obtaining sub-module is specifically configured to calculate an average value of the obtained plurality of second correlation values, and use the average value as the time domain correlation value.
Wherein the frequency-domain interpolation filter coefficient determining module 404 comprises:
the first obtaining sub-module is used for obtaining N frequency domain correlation threshold values and N-1 frequency domain interpolation coefficients; the first comparison sub-module is used for comparing the modulus of the frequency domain correlation value with a first frequency domain correlation threshold value and a second frequency domain correlation threshold value which are adjacent in the N frequency domain correlation threshold values respectively; a first determining sub-module, configured to, if a modulus of the frequency domain correlation value is greater than the first frequency domain correlation threshold value and less than or equal to the second frequency domain correlation threshold value, use a frequency domain interpolation coefficient corresponding to the first frequency domain correlation threshold value as the frequency domain interpolation filtering coefficient;
wherein N is an integer greater than 2, and the second frequency domain correlation threshold is greater than the first frequency domain correlation threshold.
Wherein the time-domain interpolation filter coefficient determining module 405 includes:
the second obtaining submodule is used for obtaining M time domain correlation threshold values and M-1 time domain interpolation coefficients; a second comparing sub-module, configured to compare the modulus of the time domain correlation value with a first time domain correlation threshold and a second time domain correlation threshold that are adjacent to each other in the M time domain correlation thresholds, respectively; a second determining submodule, configured to, if a modulus of the time domain correlation value is greater than the first time domain correlation threshold value and is less than or equal to the second time domain correlation threshold value, use a time domain interpolation coefficient corresponding to the first time domain correlation threshold value as the time domain interpolation filter coefficient; wherein M is an integer greater than 2, and the second time domain correlation threshold is greater than the first time domain correlation threshold.
In addition, as shown in fig. 5, the apparatus according to the embodiment of the present invention further includes:
a first smoothing and filtering module 407, configured to perform smoothing and filtering on the frequency domain correlation value to obtain a smoothed frequency domain correlation value; and a second smoothing and filtering module 408, configured to perform smoothing and filtering on the time domain correlation value to obtain a smoothed time domain correlation value. At this time, the frequency domain interpolation filter coefficient determining module 404 is specifically configured to determine a frequency domain interpolation filter coefficient according to the smoothed frequency domain correlation value; the time domain interpolation filter coefficient determining module 405 is specifically configured to determine a time domain interpolation filter coefficient according to the smoothed time domain correlation value.
The working principle of the device according to the invention can be referred to the description of the method embodiment described above.
Therefore, in the scheme of the embodiment of the invention, the proper interpolation filter coefficient is selected from the prestored interpolation filter coefficients through the judgment criterion to carry out channel estimation, so that the defects of time delay expansion and inaccurate Doppler frequency offset estimation caused by too few pilot frequencies in a narrow-band channel in the conventional method are avoided. Therefore, the scheme of the embodiment of the invention can obtain accurate channel estimation information in narrow-band channel transmission. In addition, in the scheme of the embodiment of the invention, the time delay expansion and the Doppler frequency offset do not need to be estimated, and the interpolation filter coefficient does not need to be calculated through the time delay expansion and the Doppler frequency offset, so that the computation load and the complexity are greatly reduced.
An embodiment of the present invention provides a data processing apparatus, including: a processor; and a memory connected to the processor through a bus interface, the memory being used to store programs and data used by the processor in performing operations, and when the processor calls and executes the programs and data stored in the memory, the memory including functional modules or units implementing:
the matrix acquisition module is used for acquiring a channel estimation matrix of a current subframe;
a frequency domain correlation value calculation module, configured to perform frequency domain correlation calculation according to the channel estimation matrix to obtain a frequency domain correlation value of the current subframe;
a time domain correlation value calculation module, configured to perform time domain correlation calculation according to the channel estimation matrix to obtain a time domain correlation value of the current subframe;
the frequency domain interpolation filter coefficient determining module is used for determining a frequency domain interpolation filter coefficient according to the frequency domain related value;
the time domain interpolation filter coefficient determining module is used for determining a time domain interpolation filter coefficient according to the time domain related value;
and the channel estimation module is used for determining the channel estimation of the frequency point to be estimated according to the frequency domain interpolation filter coefficient and the time domain interpolation filter coefficient.
It should be noted that the apparatus provided in the fourth embodiment of the present invention is an apparatus capable of correspondingly implementing the channel estimation method provided in the foregoing method embodiment, so that all embodiments of the channel estimation method provided in the foregoing method embodiment can be correspondingly applied to the fourth embodiment, and can achieve the same or similar beneficial effects.
In the several embodiments provided in the present application, it should be understood that the disclosed method and apparatus may be implemented in other ways. For example, the above-described apparatus embodiments are merely illustrative, and for example, the division of the units is only one logical division, and other divisions may be realized in practice, for example, a plurality of units or components may be combined or integrated into another system, or some features may be omitted, or not executed. In addition, the shown or discussed mutual coupling or direct coupling or communication connection may be an indirect coupling or communication connection through some interfaces, devices or units, and may be in an electrical, mechanical or other form.
In addition, functional units in the embodiments of the present invention may be integrated into one processing unit, or each unit may be physically included alone, or two or more units may be integrated into one unit. The integrated unit can be realized in a form of hardware, or in a form of hardware plus a software functional unit.
The integrated unit implemented in the form of a software functional unit may be stored in a computer readable storage medium. The software functional unit is stored in a storage medium and includes several instructions to enable a computer device (which may be a personal computer, a server, or a network device) to execute some steps of the transceiving method according to various embodiments of the present invention. And the aforementioned storage medium includes: various media capable of storing program codes, such as a usb disk, a removable hard disk, a Read-Only Memory (ROM), a Random Access Memory (RAM), a magnetic disk, or an optical disk.
While the foregoing is directed to the preferred embodiment of the present invention, it will be understood by those skilled in the art that various changes and modifications may be made without departing from the spirit and scope of the invention as defined in the appended claims.
Claims (8)
1. A method of channel estimation, comprising:
acquiring a channel estimation matrix of a current subframe;
performing frequency domain correlation calculation according to the channel estimation matrix to obtain a frequency domain correlation value of the current subframe;
performing time domain correlation calculation according to the channel estimation matrix to obtain a time domain correlation value of the current subframe;
determining a frequency domain interpolation filter coefficient according to the frequency domain correlation value, and determining a time domain interpolation filter coefficient according to the time domain correlation value;
determining channel estimation of a frequency point to be estimated according to the frequency domain interpolation filter coefficient and the time domain interpolation filter coefficient;
wherein, the step of performing frequency domain correlation calculation according to the channel estimation matrix to obtain the frequency domain correlation value of the current subframe includes:
calculating a first correlation value of channel estimation of any two adjacent pilot frequencies in each column of the channel estimation matrix;
determining a frequency domain correlation value of the current subframe by using the obtained plurality of first correlation values;
wherein, the step of performing time domain correlation calculation according to the channel estimation matrix to obtain the time domain correlation value of the current subframe comprises:
calculating a second correlation value of the channel estimation of any two adjacent pilot frequencies in each row of the channel estimation matrix;
determining a time domain correlation value of the current subframe by using the obtained plurality of second correlation values;
wherein the step of determining a frequency domain interpolation filter coefficient according to the frequency domain correlation value comprises:
acquiring N frequency domain correlation threshold values and N-1 frequency domain interpolation coefficients;
comparing the modulus of the frequency domain correlation value with a first frequency domain correlation threshold value and a second frequency domain correlation threshold value which are adjacent in the N frequency domain correlation threshold values respectively;
if the modulus of the frequency domain correlation value is larger than the first frequency domain correlation threshold value and smaller than or equal to the second frequency domain correlation threshold value, taking the frequency domain interpolation coefficient corresponding to the first frequency domain correlation threshold value as the frequency domain interpolation filter coefficient;
wherein N is an integer greater than 2, and the second frequency domain correlation threshold is greater than the first frequency domain correlation threshold;
wherein the step of determining a time-domain interpolation filter coefficient according to the time-domain correlation value includes:
obtaining M time domain correlation threshold values and M-1 time domain interpolation coefficients;
comparing the modulus of the time domain correlation value with a first time domain correlation threshold value and a second time domain correlation threshold value which are adjacent in the M time domain correlation threshold values respectively;
if the modulus of the time domain correlation value is larger than the first time domain correlation threshold value and smaller than or equal to the second time domain correlation threshold value, taking a time domain interpolation coefficient corresponding to the first time domain correlation threshold value as the time domain interpolation filter coefficient;
wherein M is an integer greater than 2, and the second time domain correlation threshold is greater than the first time domain correlation threshold.
2. The channel estimation method according to claim 1, wherein the step of determining the frequency domain correlation value of the current subframe by using the obtained plurality of first correlation values comprises:
and calculating the average value of the obtained plurality of first correlation values, and taking the average value as the frequency domain correlation value.
3. The channel estimation method according to claim 1, wherein the step of determining the frequency domain correlation value of the current subframe by using the obtained plurality of second correlation values comprises:
and calculating the average value of the obtained plurality of second correlation values, and taking the average value as the time domain correlation value.
4. The channel estimation method according to any of claims 1-3, wherein before the steps of determining frequency domain interpolation filter coefficients from the frequency domain correlation values and determining time domain interpolation filter coefficients from the time domain correlation values, the method further comprises:
carrying out smooth filtering on the frequency domain correlation value to obtain a smooth frequency domain correlation value;
performing smooth filtering on the time domain correlation value to obtain a smooth time domain correlation value;
the steps of determining a frequency domain interpolation filter coefficient according to the frequency domain correlation value and determining a time domain interpolation filter coefficient according to the time domain correlation value specifically include:
and determining a frequency domain interpolation filter coefficient according to the smooth frequency domain related value, and determining a time domain interpolation filter coefficient according to the smooth time domain related value.
5. A channel estimation device, comprising:
the matrix acquisition module is used for acquiring a channel estimation matrix of a current subframe;
a frequency domain correlation value calculation module, configured to perform frequency domain correlation calculation according to the channel estimation matrix to obtain a frequency domain correlation value of the current subframe;
a time domain correlation value calculation module, configured to perform time domain correlation calculation according to the channel estimation matrix to obtain a time domain correlation value of the current subframe;
the frequency domain interpolation filter coefficient determining module is used for determining a frequency domain interpolation filter coefficient according to the frequency domain related value;
the time domain interpolation filter coefficient determining module is used for determining a time domain interpolation filter coefficient according to the time domain related value;
the channel estimation module is used for determining the channel estimation of the frequency point to be estimated according to the frequency domain interpolation filter coefficient and the time domain interpolation filter coefficient;
wherein the frequency domain correlation value calculation module comprises:
the first calculation submodule is used for calculating a first correlation value of channel estimation of any two adjacent pilot frequencies in each column of the channel estimation matrix;
a first obtaining sub-module, configured to determine a frequency domain correlation value of the current subframe by using the obtained multiple first correlation values;
wherein the time domain correlation value calculation module comprises:
the second calculation submodule is used for calculating a second correlation value of the channel estimation of any two adjacent pilot frequencies in each row of the channel estimation matrix;
a second obtaining sub-module, configured to determine a time domain correlation value of the current subframe by using the obtained multiple second correlation values;
wherein the frequency domain interpolation filter coefficient determining module comprises:
the first obtaining sub-module is used for obtaining N frequency domain correlation threshold values and N-1 frequency domain interpolation coefficients;
the first comparison sub-module is used for comparing the modulus of the frequency domain correlation value with a first frequency domain correlation threshold value and a second frequency domain correlation threshold value which are adjacent in the N frequency domain correlation threshold values respectively;
a first determining sub-module, configured to, if a modulus of the frequency domain correlation value is greater than the first frequency domain correlation threshold value and less than or equal to the second frequency domain correlation threshold value, use a frequency domain interpolation coefficient corresponding to the first frequency domain correlation threshold value as the frequency domain interpolation filtering coefficient;
wherein N is an integer greater than 2, and the second frequency domain correlation threshold is greater than the first frequency domain correlation threshold;
wherein the time-domain interpolation filter coefficient determining module comprises:
the second obtaining submodule is used for obtaining M time domain correlation threshold values and M-1 time domain interpolation coefficients;
a second comparing sub-module, configured to compare the modulus of the time domain correlation value with a first time domain correlation threshold and a second time domain correlation threshold that are adjacent to each other in the M time domain correlation thresholds, respectively;
a second determining submodule, configured to, if a modulus of the time domain correlation value is greater than the first time domain correlation threshold value and is less than or equal to the second time domain correlation threshold value, use a time domain interpolation coefficient corresponding to the first time domain correlation threshold value as the time domain interpolation filter coefficient;
wherein M is an integer greater than 2, and the second time domain correlation threshold is greater than the first time domain correlation threshold.
6. The channel estimation device according to claim 5, wherein the first obtaining sub-module is specifically configured to: and calculating the average value of the obtained plurality of first correlation values, and taking the average value as the frequency domain correlation value.
7. The channel estimation apparatus according to claim 5, wherein the second obtaining sub-module is specifically configured to calculate an average value of the obtained plurality of second correlation values, and use the average value as the time domain correlation value.
8. The channel estimation device according to any of claims 5-7, wherein the device further comprises:
the first smoothing filtering module is used for performing smoothing filtering on the frequency domain correlation value to obtain a smooth frequency domain correlation value;
the second smoothing filtering module is used for performing smoothing filtering on the time domain correlation value to obtain a smooth time domain correlation value;
the frequency domain interpolation filter coefficient determining module is specifically configured to determine a frequency domain interpolation filter coefficient according to the smoothed frequency domain correlation value;
the time domain interpolation filter coefficient determining module is specifically configured to determine a time domain interpolation filter coefficient according to the smoothed time domain correlation value.
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