CN110048971B - Doppler frequency shift estimation method and device - Google Patents
Doppler frequency shift estimation method and device Download PDFInfo
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- CN110048971B CN110048971B CN201810035818.5A CN201810035818A CN110048971B CN 110048971 B CN110048971 B CN 110048971B CN 201810035818 A CN201810035818 A CN 201810035818A CN 110048971 B CN110048971 B CN 110048971B
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Abstract
The application discloses a Doppler frequency shift estimation method and a Doppler frequency shift estimation device, which are used for simply and accurately estimating Doppler frequency shift information, providing basis for optimizing channel interpolation, detecting terminal moving speed and mode switching of mobile communication, optimizing the performance of a receiver and improving the communication quality. The application provides a Doppler frequency shift estimation method, which comprises the following steps: determining an average Doppler frequency shift value of the current measurement period according to the amplitude average value of the imaginary part and the amplitude average value of the real part of the complex number in the plurality of pilot frequency related parameters; the pilot frequency related parameter is a related result of a first pilot frequency and a second pilot frequency; and determining the maximum Doppler frequency shift value of the current measurement period according to the average Doppler frequency shift value.
Description
Technical Field
The present application relates to the field of communications technologies, and in particular, to a doppler frequency shift estimation method and apparatus.
Background
In mobile communication, the wireless communication environment is complex, especially in urban dense areas, due to the movement of the terminal, doppler shift is generated, which causes inconsistency of the transmitting and receiving frequencies in wireless communication, and the performance of the receiver is seriously deteriorated.
In a Spatial Channel (SCM) under a long Term Evolution (L ong Term Evolution, L TE) system, the SCM supports a moving speed of up to 120km/h, generates a 250Hz doppler shift, affects the orthogonality of subcarriers of an Orthogonal Frequency Division Multiplexing (OFDM) system, generates interference between subcarriers, and thus affects the performance of a receiver, particularly the performance of a high order Quadrature Amplitude Modulation (QAM).
In an L TE uplink system, in a medium-low speed scenario, a common method is to use a DeModulation Reference Signal (DMRS) to perform frequency offset estimation and compensation, but in this scheme, the sizes of a fixed frequency offset and a doppler frequency offset cannot be effectively distinguished, that is, the doppler frequency offset and the fixed frequency offset are not distinguished, so that the frequency offset estimation and compensation are inaccurate, and further the performance of a receiver is lost.
In the existing optimization scheme, the maximum doppler value is estimated by using the relationship between the maximum doppler shift and the power spectral density function, that is, the cross-correlation function between the power spectrum and time according to the Jakes model can be expressed as:
R(Δn)＝J0(2πfDΔnTs)
wherein, J0(x) Is a first 0 th order Bessel function; f. ofDIs the maximum Doppler frequency shift value; Δ n is the number of symbols spaced between symbols; t issIs the sampling period time.
Therefore, the temperature of the molten metal is controlled,calculating to obtain time cross-correlation function R (delta n), i.e. obtaining maximum Doppler frequency shift value fD：
However, in the scheme, the cross-correlation functions of two rows of pilot frequencies are required to be calculated first, and the inverse operation of the 0-order Bessel function is calculated, so that the calculation amount is large, and the realization is not facilitated.
Disclosure of Invention
The embodiment of the application provides a Doppler frequency shift estimation method and a Doppler frequency shift estimation device, which are used for simply and accurately estimating Doppler frequency shift information, providing a basis for optimizing channel interpolation, detecting the moving speed of a terminal and switching modes of mobile communication, optimizing the performance of a receiver and improving the communication quality.
The embodiment of the application provides a Doppler frequency shift estimation method, which comprises the following steps:
determining an average Doppler frequency shift value of the current measurement period according to the amplitude average value of the imaginary part and the amplitude average value of the real part of the complex number in the plurality of pilot frequency related parameters; the pilot frequency related parameter is a related result of a first pilot frequency and a second pilot frequency;
and determining the maximum Doppler frequency shift value of the current measurement period according to the average Doppler frequency shift value.
According to the Doppler frequency shift estimation method provided by the embodiment of the application, the average Doppler frequency shift value of the current measurement period is calculated by using the amplitude average value of the imaginary part and the amplitude average value of the real part of a plurality of pilot frequency related parameters, and then the maximum Doppler frequency shift value is calculated by using the average Doppler frequency shift value, so that the Doppler frequency shift information is simply and accurately estimated, a basis is provided for optimizing channel interpolation, detecting the moving speed of a terminal and switching the mobile communication mode, the performance of a receiver is optimized, and the communication quality is improved.
Optionally, in the doppler shift estimation method provided in this embodiment of the present application, the amplitude average value of the imaginary part and the amplitude average value of the real part of the complex numbers in the plurality of pilot related parameters are determined as follows:
performing absolute value operation on an imaginary part and a real part of a complex number in a plurality of pilot frequency related parameters;
the magnitude average of the imaginary part and the magnitude average of the real part of the complex numbers in the pilot-related parameters are determined according to the magnitude absolute value of the imaginary part and the magnitude absolute value of the real part of the complex numbers in the plurality of pilot-related parameters.
According to the Doppler frequency shift estimation method provided by the embodiment of the application, the absolute value of the imaginary part and the real part of the complex number in the pilot frequency related parameters is obtained, so that the amplitude average value of a plurality of pilot frequency related parameters is not close to 0 under the condition of long measurement time, and the Doppler frequency shift value can be accurately estimated.
Optionally, in the doppler frequency shift estimation method provided in this embodiment of the present application, the determining an average doppler frequency shift value of a current measurement period according to an amplitude average value of an imaginary part and an amplitude average value of a real part of a complex number in a plurality of pilot related parameters specifically includes:
according to the amplitude average value of the imaginary part and the amplitude average value of the real part, determining the average Doppler frequency shift value f of the current measurement period according to the following formulamean：
Wherein imag (corrh) is an amplitude average of imaginary parts of complex numbers in the pilot-related parameters;
real (corrh) is the amplitude average of the real part of the complex number in the pilot-related parameter.
Optionally, in the doppler shift estimation method provided in the embodiment of the present application, the determining a maximum doppler shift value of a current measurement period according to the average doppler shift value specifically includes:
according to the average Doppler frequency shift value fmeanDetermining the maximum Doppler frequency shift value f of the current measurement period according to the following formulamax：
fmax＝2×fmean。
Optionally, in the doppler shift estimation method provided in this embodiment of the present application, the pilot-related parameter is specifically obtained by performing conjugate operation on a channel estimation result of the first pilot and a channel estimation result of the second pilot.
Optionally, in the doppler frequency shift estimation method provided in this embodiment of the present application, the first pilot frequency and the second pilot frequency are two rows of pilot frequencies in a signal with the strongest signal strength in a current measurement period.
Optionally, in the doppler shift estimation method provided in the embodiment of the present application, the method further includes:
in each output period:
storing maximum Doppler frequency shift values corresponding to all measurement periods in the current output period; wherein each output period comprises a plurality of measurement periods;
and determining the final output Doppler frequency shift value according to the maximum Doppler frequency shift value.
Optionally, in the doppler frequency shift estimation method provided in the embodiment of the present application, the determining a finally output doppler frequency shift value specifically includes:
determining the final output Doppler frequency shift value f according to the following formulas：
Wherein each output period comprises N measurement periods, fmax1，fmax2…fmaxNThe maximum Doppler frequency shift values corresponding to the N measurement periods are respectively.
Optionally, in the doppler frequency shift estimation method provided in the embodiment of the present application, the determining a finally output doppler frequency shift value specifically includes:
grouping the maximum Doppler frequency shift values corresponding to all measurement periods in the current output period; wherein, the maximum Doppler frequency shift values in each group of maximum Doppler frequency shift values have the same value;
setting the weight of each group of maximum Doppler frequency shift values; setting weights according to the number of Doppler frequency shift values contained in each group, wherein the more the number is, the larger the weight is;
and determining the numerical value of the maximum Doppler frequency shift value with the largest weight as the final output Doppler frequency shift value.
Accordingly, an embodiment of the present application provides a doppler shift estimation apparatus, including:
a first unit, configured to determine an average doppler shift value of a current measurement period according to an amplitude average value of an imaginary part and an amplitude average value of a real part of complex numbers in a plurality of pilot related parameters; the pilot frequency related parameter is a related result of a first pilot frequency and a second pilot frequency;
and the second unit is used for determining the maximum Doppler frequency shift value of the current measurement period according to the average Doppler frequency shift value.
Optionally, in the doppler shift estimation apparatus provided in this embodiment of the present application, the amplitude average of the imaginary part and the amplitude average of the real part of the complex numbers in the plurality of pilot related parameters are determined as follows:
performing absolute value operation on an imaginary part and a real part of a complex number in a plurality of pilot frequency related parameters;
the magnitude average of the imaginary part and the magnitude average of the real part of the complex numbers in the pilot-related parameters are determined according to the magnitude absolute value of the imaginary part and the magnitude absolute value of the real part of the complex numbers in the plurality of pilot-related parameters.
Optionally, in the doppler shift estimation apparatus provided in this embodiment of the present application, the first unit is specifically configured to:
according to the amplitude average value of the imaginary part and the amplitude average value of the real part, determining the average Doppler frequency shift value f of the current measurement period according to the following formulamean：
Wherein imag (corrh) is an amplitude average of imaginary parts of complex numbers in the pilot-related parameters;
real (corrh) is the amplitude average of the real part of the complex number in the pilot-related parameter.
Optionally, in the doppler shift estimation apparatus provided in this embodiment of the present application, the second unit is specifically configured to:
according to the average Doppler frequency shift value fmeanDetermining the maximum Doppler frequency shift value f of the current measurement period according to the following formulamax：
fmax＝2×fmean。
Optionally, in the doppler shift estimation apparatus provided in this embodiment of the present application, the pilot-related parameter is specifically obtained by performing conjugate operation on a channel estimation result of the first pilot and a channel estimation result of the second pilot.
Optionally, in the doppler shift estimation device provided in this embodiment of the present application, the first pilot frequency and the second pilot frequency are two rows of pilot frequencies in a signal with the strongest signal strength in the current measurement period.
Optionally, the doppler shift estimation apparatus provided in this embodiment of the present application further includes: a third unit to:
in each output period:
storing maximum Doppler frequency shift values corresponding to all measurement periods in the current output period; wherein each output period comprises a plurality of measurement periods;
and determining the final output Doppler frequency shift value according to the maximum Doppler frequency shift value.
Optionally, in the doppler shift estimation apparatus provided in this embodiment of the present application, the third unit determines the finally output doppler shift value, and specifically includes:
determining the final output Doppler frequency shift value f according to the following formulas：
Wherein each output cycle includesIncluding N measurement periods, fmax1，fmax2…fmaxNThe maximum Doppler frequency shift values corresponding to the N measurement periods are respectively.
Optionally, in the doppler shift estimation apparatus provided in this embodiment of the present application, the third unit determines the finally output doppler shift value, and specifically includes:
grouping the maximum Doppler frequency shift values corresponding to all measurement periods in the current output period; wherein, the maximum Doppler frequency shift values in each group of maximum Doppler frequency shift values have the same value;
setting the weight of each group of maximum Doppler frequency shift values; setting weights according to the number of Doppler frequency shift values contained in each group, wherein the more the number is, the larger the weight is;
the value of the set of maximum doppler shift values with the largest weight is determined as the final output doppler shift value.
An embodiment of the present application provides a doppler shift estimation device, including:
at least one processor, and
a memory communicatively coupled to the at least one processor;
wherein the memory stores instructions executable by the at least one processor, and the at least one processor performs any of the methods described above by executing the instructions stored by the memory.
Embodiments of the present application provide a computer-readable storage medium storing computer instructions, which, when executed on a computer, cause the computer to perform any one of the methods described above.
Drawings
Fig. 1 is a schematic diagram of a receiver;
fig. 2 is a flowchart of a doppler shift estimation method according to an embodiment of the present application;
fig. 3 is a second flowchart of a doppler shift estimation method according to an embodiment of the present application;
fig. 4 is a third flowchart of a doppler shift estimation method according to an embodiment of the present application;
fig. 5 is a block diagram of a doppler shift estimation device according to an embodiment of the present application;
fig. 6 is a block diagram of another doppler shift estimation device according to an embodiment of the present application.
Detailed Description
In order to make the aforementioned objects, features and advantages of the present application more comprehensible, the present application is further described with reference to the accompanying drawings and examples. Example embodiments may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the concept of example embodiments to those skilled in the art.
It should be noted that in the following description, specific details are set forth in order to provide a thorough understanding of the present application. This application is capable of implementation in many different ways than those herein set forth and of similar import to those skilled in the art without departing from the spirit and scope of this application. The present application is therefore not limited to the specific embodiments disclosed below.
The doppler shift estimation method and apparatus provided in the embodiments of the present application are specifically described below with reference to the accompanying drawings.
In mobile communication, after a receiving end receives a signal, as shown in fig. 1, a digital front-end DFE module 01 converts the received signal into a signal that can be sampled, an automatic gain control AGC/automatic frequency control AFC module 02 receives the signal processed by the DFE 01, performs gain processing on the signal, inputs the signal into a fast fourier transform FFT module 03, inputs the signal into a channel estimation module 05 after FFT operation, performs channel estimation in combination with a DMRS signal input by a local DMRS module 04, wherein a part of the signal is input into a doppler frequency estimation module 06 for estimating doppler frequency shift information, a part of the signal is input into a signal interpolation module 07, and after channel interpolation calculation, the signal is input into a signal equalization processing module 08 for equalization processing, and then input into a channel decoding module 09 for channel decoding; on the other hand, part of the signals input to the doppler shift estimation module 06 are calculated to determine the finally output doppler shift value, and the doppler shift value is input to the channel estimation module 05 to provide a reference basis for channel estimation; meanwhile, the doppler frequency shift value can also be input to the terminal speed estimation module 10 for detecting the moving speed of the terminal, and the moving speed detection result is input to the mode switching module 11, so that a reference basis is provided for mode switching of mobile communication, the performance of the receiver is optimized, and the communication quality is improved.
As shown in fig. 2, the method for estimating a doppler shift according to an embodiment of the present invention may specifically include the following steps:
s201, determining an average Doppler frequency shift value of a current measurement period according to an amplitude average value of an imaginary part and an amplitude average value of a real part of a plurality of pilot frequency related parameters; the pilot frequency related parameter is a related result of a first pilot frequency and a second pilot frequency;
s202, determining the maximum Doppler frequency shift value of the current measurement period according to the average Doppler frequency shift value.
Optionally, in specific implementation, in the doppler shift estimation method provided in this embodiment of the present application, the first pilot and the second pilot may be, for example, two columns of pilots in a signal with the strongest signal strength in a current measurement period. Specifically, in the antenna array, a signal received by an antenna with the strongest received signal strength is a target signal, the target signal includes a DMRS symbol, and the DMRS symbol is an uplink pilot; two DMRS symbols (i.e., a first pilot and a second pilot) are selected for channel estimation, so that doppler frequency shift estimation can be performed by using frequency domain channel estimation results of the first pilot and the second pilot, and since the signal strength of a target signal is high, the first pilot and the second pilot are determined from the target signal for doppler frequency shift estimation, so that the accuracy of the doppler frequency shift estimation result is improved.
Optionally, in a specific implementation, in the doppler shift estimation method provided in this embodiment of the present application, the pilot-related parameter may be obtained by performing a conjugate operation on a channel estimation result of the first pilot and a channel estimation result of the second pilot, for example. Specifically, assume that H1(n) is the channel estimation result of the first pilot, and H2(n) is the channel estimation result of the second pilot; the channel estimation result may be, for example, a numerical group including a complex number, and specifically, how to perform channel estimation is the prior art, which is not described herein again; the first pilot and the second pilot include multiple subcarriers, that is, H1(n) ═ H11, H12, … H1n ], H2(n) ═ H21, H22, … H2n, where n is the number of subcarriers in the pilot; the pilot correlation parameter corrh (n) is a correlation result of the first pilot and the second pilot, and corrh (n) can be determined according to the following formula, for example:
CorrH(n)＝H1(n)×conj[H2(n)]
where, conj (x) is a conjugate function, which is used to calculate the complex conjugate of x, i.e. corrh (n) can be the product of the channel estimation result H1(n) of the first pilot and the complex conjugate of the channel estimation result H2(n) of the second pilot, which is used to represent the correlation between two columns of pilots and the change of the signal generated by the terminal moving between different times corresponding to the two columns of pilots, so as to estimate the doppler shift value.
Alternatively, as shown in fig. 3, in a specific implementation, in the doppler frequency shift estimation method provided in this embodiment of the present application, the average doppler frequency shift value of the current measurement period may be determined according to an average amplitude value of an imaginary part and an average amplitude value of a real part of a complex number in a plurality of pilot-related parameters, which may be determined, for example, in the following manner:
s301, performing absolute value operation on imaginary parts and real parts of complex numbers in a plurality of pilot frequency related parameters;
s302, according to the amplitude absolute value of the imaginary part and the amplitude absolute value of the real part of the complex numbers in the plurality of pilot frequency related parameters, the amplitude average value of the imaginary part and the amplitude average value of the real part of the complex numbers in the pilot frequency related parameters are determined.
Specifically, the pilot-related parameter CorrH (n) ═ CorrH1, CorrH2, … CorrHn ]; wherein, CorrH1 is the product of the complex conjugate of the channel estimation result H11 corresponding to the 1 st subcarrier in the first pilot and the channel estimation result H21 corresponding to the 1 st subcarrier in the second pilot; CorrH2 is the channel estimation result H12 corresponding to the 2 nd subcarrier in the first pilot, and the product … … CorrHn of the complex conjugate of the channel estimation result H22 corresponding to the 2 nd subcarrier in the second pilot is the product of the complex conjugate of the channel estimation result H1n corresponding to the nth subcarrier in the first pilot and the channel estimation result H2n corresponding to the nth subcarrier in the second pilot. Since the complex numbers have positive and negative values on the coordinate axis and have small distances from the coordinate axis, in the case of a long measurement time, i.e. a large number of statistics, the sum of the plurality of pilot-related parameters approaches 0, and thus the average of the amplitudes of the plurality of pilot-related parameters approaches 0, the absolute values of the real and imaginary parts of the complex numbers in the pilot-related parameters CorrH (n) may be calculated, so as to obtain the absolute values of the amplitudes of the imaginary parts and the absolute values of the real parts of the complex numbers in the plurality of pilot-related parameters, i.e. to obtain the absolute values of the amplitudes of CorrH1, CorrH2, … CorrHn, i.e. to obtain the absolute values of the amplitudes of the imaginary parts (CorrH1), imag (CorrH2) … … imag (CorrHn) and the real parts of real parts (CorrH1), real parts (CorrH2) … … CorrHn) such that in the case of a large number of statistics, the absolute values of the amplitudes of the imaginary parts and the average of the complex parts of the plurality of pilot-related parameters and the real parts of the CorrH 360 are not close to the real parts of the CorrH1, and the real parts of the CorrH (CorrH2), thereby accurately estimating the Doppler frequency shift value; then, the amplitude absolute value of the imaginary part of the complex number in the pilot frequency related parameters is added and divided by the number of the pilot frequency related parameters to obtain the amplitude average value imag (CorrH) of the imaginary part of the complex number in the pilot frequency related parameters; the amplitude average real part real (corrh) of the complex numbers in the pilot-related parameters is obtained by adding the absolute amplitude of the real parts of the complex numbers in the plurality of pilot-related parameters and dividing by the number of the pilot-related parameters. Of course, the amplitude average of the imaginary part and the amplitude average of the real part of the complex numbers in the pilot-related parameters may also be determined in other manners, and may be specifically designed according to the requirement, as long as the principle of the present application is met, and the present invention is not limited thereto.
Optionally, in a specific implementation, in the doppler frequency shift estimation method provided in this embodiment of the present application, the above-mentioned average value of the amplitudes of the imaginary parts and the average value of the amplitudes of the real parts of the complex numbers in the pilot-related parameters are used to determine an average doppler frequency shift value of the current measurement period, where the determining the average doppler frequency shift value of the current measurement period according to the average value of the amplitudes of the imaginary parts and the average value of the amplitudes of the real parts of the complex numbers in the multiple pilot-related parameters specifically includes:
from the amplitude average value of the imaginary part and the amplitude average value of the real part, the average Doppler frequency shift value f of the current measurement period can be determined, for example, according to the following formulamean：
Wherein imag (corrh) is an amplitude average of imaginary parts of complex numbers in the pilot-related parameters;
real (corrh) is the amplitude average of the real part of the complex number in the pilot-related parameter.
Optionally, in specific implementation, in the doppler frequency shift estimation method provided in this embodiment of the present application, an average doppler frequency shift value is determined, and then a maximum doppler frequency shift value may be determined, specifically, the determining a maximum doppler frequency shift value of a current measurement period according to the average doppler frequency shift value specifically includes:
according to the average Doppler frequency shift value fmeanFor example, the maximum Doppler frequency shift value f of the current measurement period can be determined according to the following formulamax：
fmax＝2×fmean。
Of course, the maximum doppler frequency shift value may also be obtained by other methods, and a specific algorithm may be designed according to actual needs, which is not limited herein.
In the doppler frequency shift estimation method provided in the embodiment of the present application, the average value of the real part and the average value of the imaginary part of the pilot frequency related parameter are substituted into the above formula to obtain the average doppler frequency shift value, and then the maximum doppler frequency shift value is estimated from the average doppler frequency shift value, thereby simplifying the operation process of doppler frequency shift estimation, ensuring the accuracy of the estimation result, providing a basis for optimizing channel interpolation, detecting the terminal moving speed, and switching the mobile communication mode, optimizing the performance of the receiver, and improving the communication quality.
Optionally, in a specific implementation, in the doppler shift estimation method provided in this embodiment of the present application, an instantaneous measured maximum doppler shift value (that is, the maximum doppler shift value measured in each measurement period) may be affected by channel jitter to generate an error, so that an output period may be set as needed, each output period includes a plurality of measurement periods, the operation is performed in each measurement period to obtain the maximum doppler shift value corresponding to the measurement period, and the maximum doppler shift values obtained in the plurality of measurement periods are filtered to obtain a final output doppler shift value, so as to improve accuracy of a result of doppler shift estimation.
Specifically, as shown in fig. 4, in each output period, the following steps may be performed:
s401, storing maximum Doppler frequency shift values corresponding to all measurement periods in the current output period; wherein each output period comprises a plurality of measurement periods;
s402, determining a final output Doppler frequency shift value according to the maximum Doppler frequency shift value.
Specifically, the following two ways of determining the final output doppler frequency shift value are exemplified, but not limited to the following two ways of determining the final output doppler frequency shift value.
In a first way,
Optionally, in a specific implementation, in the doppler shift estimation method provided in the embodiment of the present application, the determining a finally output doppler shift value may include:
determining the final output Doppler frequency shift value f according to the following formulas：
Wherein each output period comprises N measurement periods, fmax1，fmax2…fmaxNThe maximum Doppler frequency shift values corresponding to the N measurement periods are respectively. Receiving and storing the maximum Doppler frequency shift values determined by the N measurement periods, carrying out square operation on the maximum Doppler frequency shift value of each measurement period, averaging the results of the square operations, carrying out square operation to obtain the final output Doppler frequency shift value, and carrying out filtering calculation on the maximum Doppler frequency shift values corresponding to the measurement periods according to the formula to improve the accuracy of Doppler frequency shift estimation.
The second way,
Optionally, in a specific implementation, in the doppler shift estimation method provided in the embodiment of the present application, the determining a finally output doppler shift value may include:
grouping the maximum Doppler frequency shift values corresponding to all measurement periods in the current output period; wherein, the maximum Doppler frequency shift values in each group of maximum Doppler frequency shift values have the same value;
setting the weight of each group of maximum Doppler frequency shift values; setting weights according to the number of Doppler frequency shift values contained in each group, wherein the more the number is, the larger the weight is;
and determining the numerical value of the maximum Doppler frequency shift value with the largest weight as the final output Doppler frequency shift value.
Specifically, it is assumed that one output period includes 6 measurement periods, and maximum doppler frequency shift values corresponding to the 6 measurement periods are respectively: fmax 1-100, fmax 2-150, fmax 3-100, fmax 4-90, fmax 5-150, fmax 6-100; maximum doppler shift values fmax1, fmax2, fmax3, fmax4, fmax5, fmax6 corresponding to 6 measurement periods are grouped, wherein the maximum doppler shift values in each group of maximum doppler shift values have equal values, i.e. the 6 maximum doppler shift values are grouped into 3 groups:
a first group: { fmax1, fmax3, fmax6} ═ 100;
second group: { fmax2, fmax5} ═ 150;
third group: { fmax4} ═ 90;
the more the number of the maximum Doppler frequency shift values contained in each group is, the maximum probability of measuring the numerical value of the maximum Doppler frequency shift value in the current output period is shown, so the weight of the maximum Doppler frequency shift value in each group is set according to the number of the maximum Doppler frequency shift values contained in each group; the first group has the largest weight, the second group has the smaller weight than the first group and is larger than the third group, and the third group has the smallest weight;
and determining the value of the first group of maximum Doppler frequency shift values with the largest weight as the final output Doppler frequency shift value, namely the final output Doppler frequency shift value is 100. By carrying out filtering calculation on a plurality of maximum Doppler frequency shift values corresponding to a plurality of measurement periods according to the method, the accuracy of Doppler frequency shift estimation is improved.
Of course, the method for determining the final output doppler frequency shift value from the multiple maximum doppler frequency shift values is not limited to the above manner, for example, an arithmetic mean value may be obtained for the multiple maximum doppler frequency shift values to serve as the final output doppler frequency shift value, and a specific algorithm may be designed according to actual needs, which is not limited herein.
Based on the same inventive concept, as shown in fig. 5, an embodiment of the present application provides a doppler shift estimation apparatus, including:
a first unit 501, configured to determine an average doppler frequency shift value of a current measurement period according to an amplitude average value of an imaginary part and an amplitude average value of a real part of complex numbers in a plurality of pilot related parameters; the pilot frequency related parameter is a related result of a first pilot frequency and a second pilot frequency;
a second unit 502, configured to determine a maximum doppler frequency shift value of the current measurement period according to the average doppler frequency shift value.
Optionally, in the doppler shift estimation apparatus provided in this embodiment of the present application, the amplitude average of the imaginary part and the amplitude average of the real part of the complex numbers in the plurality of pilot related parameters are determined as follows:
performing absolute value operation on an imaginary part and a real part of a complex number in a plurality of pilot frequency related parameters;
the magnitude average of the imaginary part and the magnitude average of the real part of the complex numbers in the pilot-related parameters are determined according to the magnitude absolute value of the imaginary part and the magnitude absolute value of the real part of the complex numbers in the plurality of pilot-related parameters.
Optionally, in the doppler shift estimation apparatus provided in this embodiment of the present application, the first unit 501 is specifically configured to:
according to the amplitude average value of the imaginary part and the amplitude average value of the real part, determining the average Doppler frequency shift value f of the current measurement period according to the following formulamean：
Wherein imag (corrh) is an amplitude average of imaginary parts of complex numbers in the pilot-related parameters;
real (corrh) is the amplitude average of the real part of the complex number in the pilot-related parameter.
Optionally, in the doppler shift estimation apparatus provided in this embodiment of the present application, the second unit 502 is specifically configured to:
according to the average Doppler frequency shift value fmeanDetermining the maximum Doppler frequency shift value f of the current measurement period according to the following formulamax：
fmax＝2×fmean。
Optionally, in the doppler shift estimation apparatus provided in this embodiment of the present application, the pilot-related parameter may be obtained, for example, by performing a conjugate operation on a channel estimation result of the first pilot and a channel estimation result of the second pilot.
Optionally, in the doppler shift estimation device provided in this embodiment of the present application, the first pilot frequency and the second pilot frequency are two rows of pilot frequencies in a signal with the strongest signal strength in the current measurement period.
Optionally, the doppler shift estimation apparatus provided in this embodiment of the present application further includes: a third unit to:
in each output period:
storing maximum Doppler frequency shift values corresponding to all measurement periods in the current output period; wherein each output period comprises a plurality of measurement periods;
and determining the final output Doppler frequency shift value according to the maximum Doppler frequency shift value.
Optionally, in the doppler shift estimation apparatus provided in this embodiment of the present application, the third unit determines the finally output doppler shift value, and specifically includes:
determining the final output Doppler frequency shift value f according to the following formulas：
Wherein each output period comprises N measurement periods, fmax1，fmax2…fmaxNThe maximum Doppler frequency shift values corresponding to the N measurement periods are respectively.
Optionally, in the doppler shift estimation apparatus provided in this embodiment of the present application, the third unit determines the finally output doppler shift value, and specifically includes:
grouping the maximum Doppler frequency shift values corresponding to all measurement periods in the current output period; wherein, the maximum Doppler frequency shift values in each group of maximum Doppler frequency shift values have the same value;
setting the weight of each group of maximum Doppler frequency shift values; setting weights according to the number of Doppler frequency shift values contained in each group, wherein the more the number is, the larger the weight is;
and determining the numerical value of the maximum Doppler frequency shift value with the largest weight as the final output Doppler frequency shift value.
Based on the same inventive concept, as shown in fig. 6, an embodiment of the present application provides another doppler shift estimation apparatus, which includes the doppler shift estimation apparatus provided in the embodiment of the present application, and the apparatus may include at least one processor 601, and
a memory 602 communicatively coupled to the at least one processor 601;
wherein the memory 602 stores instructions executable by the at least one processor 601, and the at least one processor 601 performs any of the methods described above by executing the instructions stored by the memory 602.
The processor 601 is configured to execute any of the methods provided by the embodiments of the present application according to the obtained program instructions by calling the program instructions stored in the memory.
As shown in fig. 6, the apparatus may further include a communication interface 603, which may be an external interface or a built-in interface, and the at least one processor 601 performs any one of the above methods by using the communication interface 603.
In addition, the embodiment of the present application also provides a computer storage medium for storing computer program instructions for the above computing device, which contains a program for executing any one of the methods provided by the embodiments of the present application.
The computer storage media may be any available media or data storage device that can be accessed by a computer, including but not limited to magnetic memory (e.g., floppy disks, hard disks, magnetic tape, magneto-optical disks (MOs), etc.), optical memory (e.g., CDs, DVDs, BDs, HVDs, etc.), and semiconductor memory (e.g., ROMs, EPROMs, EEPROMs, non-volatile memory (NAND F L ASH), Solid State Disks (SSDs)), etc.
In summary, in the doppler frequency shift estimation method provided in the embodiment of the present application, an average doppler frequency shift value of a current measurement period is calculated by using an average value of amplitudes of imaginary parts and an average value of amplitudes of real parts of a plurality of pilot related parameters, and then a maximum doppler frequency shift value is calculated by using the average doppler frequency shift value, so that doppler frequency shift information is simply and accurately estimated, a basis is provided for optimizing channel interpolation, detecting a terminal moving speed, and mode switching of mobile communication, performance of a receiver is optimized, and communication quality is improved.
While the preferred embodiments of the present application have been described, additional variations and modifications in those embodiments may occur to those skilled in the art once they learn of the basic inventive concepts. Therefore, it is intended that the appended claims be interpreted as including preferred embodiments and all alterations and modifications as fall within the scope of the application.
As will be appreciated by one skilled in the art, embodiments of the present application may be provided as a method, system, or computer program product. Accordingly, the present application may take the form of an entirely hardware embodiment, an entirely software embodiment or an embodiment combining software and hardware aspects. Furthermore, the present application may take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, optical storage, and the like) having computer-usable program code embodied therein.
The present application is described with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the application. It will be understood that each flow and/or block of the flow diagrams and/or block diagrams, and combinations of flows and/or blocks in the flow diagrams and/or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer, special purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.
It will be apparent to those skilled in the art that various changes and modifications may be made in the present application without departing from the spirit and scope of the application. Thus, if such modifications and variations of the present application fall within the scope of the claims of the present application and their equivalents, the present application is intended to include such modifications and variations as well.
Claims (18)
1. A method of doppler frequency shift estimation, comprising:
determining an average Doppler frequency shift value of the current measurement period according to the amplitude average value of the imaginary part and the amplitude average value of the real part of the complex number in the plurality of pilot frequency related parameters; the pilot frequency related parameter is a related result of a first pilot frequency and a second pilot frequency;
determining the maximum Doppler frequency shift value of the current measurement period according to the average Doppler frequency shift value;
wherein, the determining the average doppler frequency shift value of the current measurement period according to the amplitude average value of the imaginary part and the amplitude average value of the real part of the complex number in the plurality of pilot related parameters specifically includes:
according to the amplitude average value of the imaginary part and the amplitude average value of the real part, determining the average Doppler frequency shift value f of the current measurement period according to the following formulamean：
Wherein imag (corrh) is an amplitude average of imaginary parts of complex numbers in the pilot-related parameters; real (corrh) is the amplitude average of the real part of the complex number in the pilot-related parameter.
2. The method of claim 1, wherein the magnitude average of the imaginary part and the magnitude average of the real part of the complex numbers in the plurality of pilot-related parameters are determined as follows:
performing absolute value operation on an imaginary part and a real part of a complex number in a plurality of pilot frequency related parameters;
the magnitude average of the imaginary part and the magnitude average of the real part of the complex numbers in the pilot-related parameters are determined according to the magnitude absolute value of the imaginary part and the magnitude absolute value of the real part of the complex numbers in the plurality of pilot-related parameters.
3. The method of claim 1, wherein the determining the maximum doppler shift value for the current measurement period based on the average doppler shift value comprises:
according to the average Doppler frequency shift value fmeanDetermining the maximum Doppler frequency shift value f of the current measurement period according to the following formulamax：
fmax＝2×fmean。
4. The method of claim 1, wherein the pilot-related parameter is obtained by performing a conjugate operation using a channel estimation result of the first pilot and a channel estimation result of the second pilot.
5. The method of claim 1, wherein the first pilot and the second pilot are two columns of pilots in a signal with the strongest signal strength received in a current measurement period.
6. The method of claim 1, further comprising:
in each output period:
storing maximum Doppler frequency shift values corresponding to all measurement periods in the current output period; wherein each output period comprises a plurality of measurement periods;
and determining the final output Doppler frequency shift value according to the maximum Doppler frequency shift value.
7. The method of claim 6, wherein the determining the final output doppler shift value comprises:
determining the final output Doppler frequency shift value f according to the following formulas：
Wherein each output periodComprising N measurement periods, fmax1，fmax2…fmaxNThe maximum Doppler frequency shift values corresponding to the N measurement periods are respectively.
8. The method of claim 6, wherein the determining the final output doppler shift value comprises:
grouping the maximum Doppler frequency shift values corresponding to all measurement periods in the current output period; wherein, the maximum Doppler frequency shift values in each group of maximum Doppler frequency shift values have the same value;
setting the weight of each group of maximum Doppler frequency shift values; setting weights according to the number of Doppler frequency shift values contained in each group, wherein the more the number is, the larger the weight is;
and determining the numerical value of the maximum Doppler frequency shift value with the largest weight as the final output Doppler frequency shift value.
9. An apparatus for estimating a doppler shift, the apparatus comprising:
a first unit, configured to determine an average doppler shift value of a current measurement period according to an amplitude average value of an imaginary part and an amplitude average value of a real part of complex numbers in a plurality of pilot related parameters; the pilot frequency related parameter is a related result of a first pilot frequency and a second pilot frequency;
a second unit, configured to determine a maximum doppler frequency shift value of the current measurement period according to the average doppler frequency shift value;
wherein the first unit is specifically configured to:
according to the amplitude average value of the imaginary part and the amplitude average value of the real part, determining the average Doppler frequency shift value f of the current measurement period according to the following formulamean：
Wherein imag (corrh) is an amplitude average of imaginary parts of complex numbers in the pilot-related parameters; real (corrh) is the amplitude average of the real part of the complex number in the pilot-related parameter.
10. The apparatus of claim 9, wherein the magnitude average of the imaginary part and the magnitude average of the real part of the complex numbers in the plurality of pilot-related parameters are determined as follows:
performing absolute value operation on an imaginary part and a real part of a complex number in a plurality of pilot frequency related parameters;
the magnitude average of the imaginary part and the magnitude average of the real part of the complex numbers in the pilot-related parameters are determined according to the magnitude absolute value of the imaginary part and the magnitude absolute value of the real part of the complex numbers in the plurality of pilot-related parameters.
11. The apparatus of claim 9, wherein the second unit is specifically configured to:
according to the average Doppler frequency shift value fmeanDetermining the maximum Doppler frequency shift value f of the current measurement period according to the following formulamax：
fmax＝2×fmean。
12. The apparatus as claimed in claim 9, wherein the pilot-related parameter is obtained by performing a conjugate operation using the channel estimation result of the first pilot and the channel estimation result of the second pilot.
13. The apparatus of claim 9, wherein the first pilot and the second pilot are two columns of pilots in a signal with the strongest signal strength received in a current measurement period.
14. The apparatus of claim 9, further comprising: a third unit to:
in each output period:
storing maximum Doppler frequency shift values corresponding to all measurement periods in the current output period; wherein each output period comprises a plurality of measurement periods;
and determining the final output Doppler frequency shift value according to the maximum Doppler frequency shift value.
15. The apparatus of claim 14, wherein the third unit determines the final output doppler shift value by:
determining the final output Doppler frequency shift value f according to the following formulas：
Wherein each output period comprises N measurement periods, fmax1，fmax2…fmaxNThe maximum Doppler frequency shift values corresponding to the N measurement periods are respectively.
16. The apparatus of claim 15, wherein the third unit determines the final output doppler shift value by:
grouping the maximum Doppler frequency shift values corresponding to all measurement periods in the current output period; wherein, the maximum Doppler frequency shift values in each group of maximum Doppler frequency shift values have the same value;
setting the weight of each group of maximum Doppler frequency shift values; setting weights according to the number of Doppler frequency shift values contained in each group, wherein the more the number is, the larger the weight is;
and determining the numerical value of the maximum Doppler frequency shift value with the largest weight as the final output Doppler frequency shift value.
17. A doppler shift estimation device, comprising:
at least one processor, and
a memory communicatively coupled to the at least one processor;
wherein the memory stores instructions executable by the at least one processor, the at least one processor performing the method of any one of claims 1-8 by executing the instructions stored by the memory.
18. A computer-readable storage medium having stored thereon computer instructions which, when executed on a computer, cause the computer to perform the method of any one of claims 1-8.
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