Method and device for determining frequency deviation value of signal

Abstract

A method and device for determining the frequency deviation value of a signal, the method comprising: using multiple antennas to receive multiple received signals, the multiple received signals received by each antenna having respective arrival times and arrival angles; performing beam decomposition on the multiple received signals received by the multiple antennas to obtain received signals on multiple beams, the multiple received signals on each beam having respective arrival times and belonging to the same arrival angle interval; performing frequency deviation estimation on the received signals on each beam to obtain the frequency deviation value of the received signals on each beam. The technical solution helps to quickly and accurately determine the frequency deviation values ​​of received signals in different arrival angle directions.

Description

Technical Field

[0001] The present invention relates to the field of communication technology, and in particular to a method and device for determining a frequency deviation value of a signal. Background Art

[0002] In the field of communication technology, when there is relative motion between the signal transmitting end (transmitter) and the signal receiving end (receiver), the frequency of the electromagnetic wave signal received by the receiver is not the same as the frequency of the electromagnetic wave signal emitted by the transmitter. This is the so-called Doppler effect, where the difference between the frequency of the received signal and the frequency of the transmitted signal is called the Doppler frequency shift or Doppler frequency deviation.

[0003] When a signal is transmitted to a moving receiver at only one arrival angle (incident angle), there is only one Doppler frequency shift; however, in the currently widely used wireless channel transmission, the propagation path between the transmitter and the receiver is often very complex, and may encounter various obstacles such as mountains, trees, and buildings. When a sine wave is transmitted to a moving receiver through a wireless channel with very rich multipath components and receiving arrival angles in all directions, the Doppler effect will occur due to the relative motion between the transmitter and the receiver, and multiple Doppler frequency shifts will be generated. The spectrum of the received signal will be broadened, which is called Doppler spread (including spectrum components with frequencies of fc-fm to fc+fm, fc is the original frequency value of the signal transmitted by the transmitter, and fm is the maximum Doppler frequency deviation value). In the above case, the signal received by the receiver may experience varying degrees of fading. By determining the frequency deviation value of the received signal, the signal can be corrected for frequency deviation and the Doppler spread spectrum can be determined for wider applications.

[0004] In the prior art, for a signal with only one incoming wave direction, since Doppler expansion does not occur (i.e., a collection of multiple different Doppler frequency shifts does not occur), a common technique for determining the frequency deviation value of the received signal is: using received signals with a certain time interval, after compensating for the phase influence of the corresponding transmitted signal, calculating the correlation values ​​between the received signals pairwise, and using the phase information of the correlation values ​​and their time intervals to estimate the signal frequency deviation value. However, if the received signal arrives at the receiving end at multiple arrival angles, it may take a longer time for the received signal to perform frequency deviation estimation, and some complex frequency deviation estimation algorithms need to be used, and the calculation process is time-consuming and cumbersome, and the accuracy is insufficient.

[0005] Therefore, there is an urgent need for a method for determining a frequency deviation value of a signal, which helps to quickly and accurately determine the frequency deviation values ​​of received signals in multiple different arrival angle directions. Summary of the invention

[0006] The technical problem solved by the present invention is how to quickly and accurately determine the frequency deviation values ​​of received signals in multiple wave directions with different arrival angles.

[0007] An embodiment of the present invention provides a method for determining the frequency deviation value of a signal, comprising the following steps: using multiple antennas to receive multiple received signals, the multiple received signals received by each antenna having respective arrival times and arrival angles; performing beam decomposition on the multiple received signals received by the multiple antennas to obtain received signals on multiple beams, the multiple received signals on each beam having respective arrival times and belonging to the same arrival angle interval; performing frequency deviation estimation on the received signal on each beam to obtain the frequency deviation value of the received signal on each beam.

[0008] Optionally, the method further includes: performing frequency deviation correction on the received signal on each beam according to the frequency deviation value of the received signal on each beam.

[0009] Optionally, performing beam decomposition on the multiple received signals received by the multiple antennas to obtain received signals on multiple beams includes: performing orthogonal beam decomposition on the multiple received signals received by the multiple antennas to obtain received signals on all or part of the beams.

[0010] Optionally, performing orthogonal beam decomposition on the multiple received signals received by the multiple antennas to obtain received signals on some beams includes: performing orthogonal beam decomposition on the multiple received signals received by the multiple antennas, and calculating the signal-to-noise ratio mean and energy mean of the multiple received signals on each of the beams obtained; and selecting a beam whose signal-to-noise ratio mean is greater than a first preset threshold or whose energy mean is greater than a second preset threshold to obtain the received signals on the some beams.

[0011] Optionally, beam decomposing the multiple received signals received by the multiple antennas to obtain received signals on multiple beams includes: using an arrival angle estimation algorithm to estimate the arrival angles of the multiple received signals received by the multiple antennas to obtain multiple arrival angles, and then aligning the peak directions of the beams of the multiple received signals with the estimated arrival angle directions to obtain the received signals on the multiple beams.

[0012] Optionally, the arrival angle estimation algorithm is selected from: Bartlett algorithm, Capon algorithm, and multiple signal classification MUSIC algorithm.

[0013] Optionally, the frequency deviation estimation of the received signal on each beam to obtain the frequency deviation value of the received signal on each beam includes: for each beam, calculating the correlation value of each two received signals corresponding to different sending times among the multiple received signals on the beam, and calculating the initial frequency deviation value based on the correlation value; and determining the frequency deviation value of the received signal on the beam based on the multiple initial frequency deviation values ​​obtained.

[0014] Optionally, for each beam, the following formula is used to calculate a correlation value of each two received signals corresponding to different transmission times among multiple received signals on the beam, and an initial frequency offset value is calculated according to the correlation value:

[0015] R=r(t0)×s*(t0)×r*(t1)×s(t1);

[0016]

[0017] Among them, f d Used to indicate the initial frequency deviation value; R is used to indicate the correlation value between the two signals; angle() is used to indicate the phase angle function of the complex number; r(t0) is used to indicate the received signal on a certain beam with the transmission time t0; r*(t1) is used to indicate the conjugate complex number of the received signal on a certain beam with the transmission time t1; s*(t0) is used to indicate the conjugate complex number of the transmitted signal s(t0) corresponding to r(t0); s(t1) is used to indicate the transmitted signal corresponding to r(t1); wherein t1>t0, and satisfies

[0018] Optionally, determining the frequency deviation value of the received signal on the beam based on the multiple initial frequency deviation values ​​obtained includes: taking the average value of the multiple initial frequency deviation values ​​obtained as the frequency deviation value of the received signal on the beam; or taking the median value of the multiple initial frequency deviation values ​​obtained as the frequency deviation value of the received signal on the beam.

[0019] Optionally, after obtaining the frequency deviation value of the received signal on each beam, the method further includes: determining a Doppler spread spectrum according to the frequency deviation value and power average of the received signal on each beam.

[0020] Optionally, a channel estimation value after time-domain minimum mean square error MMSE filtering is calculated according to the Doppler spread spectrum.

[0021] Optionally, the following formula is used to calculate the channel estimation value after time-domain minimum mean square error MMSE filtering according to the Doppler spread spectrum:

[0022] H t′mmse (l) = R H′H ×(R HH +σ 2 l) -1 ×H LS ;

[0023] Among them, H t′mmse (l) is used to indicate the channel estimation value after time-domain MMSE filtering of the lth OFDM symbol; R HH N is used to indicate time domain contiguous tfiltThe first channel correlation matrix of OFDM symbols containing pilots is N tfilt ×N tfilt ; R H′H Used to indicate the relationship between the lth OFDM symbol and the N nearest OFDM symbol. tfilt The second channel correlation matrix of OFDM symbols containing pilots is 1×N tfilt ;H LS Used to indicate the N nearest to the lth OFDM symbol tfilt The matrix of channel estimates before time-domain MMSE filtering of OFDM symbols containing pilots is N tfilt ×1; where N tfilt Used to indicate the order of the time domain MMSE filter; σ 2 To indicate H LS The noise power on .

[0024] Optionally, the multiple antennas satisfy one or more of the following: the multiple antennas are arranged in an array; the arrangement direction of the multiple antennas on the receiver is parallel to the movement direction of the receiver; the spacing between adjacent positions of the multiple antennas is less than half of the carrier wavelength of the transmitted signal.

[0025] Optionally, the multiple antennas are arranged in an array that satisfies one or more of the following: the multiple antennas are arranged in a linear array; the multiple antennas are arranged in a planar array; the multiple antennas are arranged in a spherical array.

[0026] An embodiment of the present invention also provides a device for determining the frequency deviation value of a signal, comprising: a signal receiving module, used to use multiple antennas to receive multiple received signals, the multiple received signals received by each antenna have respective arrival times and arrival angles; a beam decomposition module, used to perform beam decomposition on the multiple received signals received by the multiple antennas to obtain received signals on multiple beams, the multiple received signals on each beam have respective arrival times and belong to the same arrival angle interval; a frequency deviation value determination module, used to perform frequency deviation estimation on the received signal on each beam to obtain the frequency deviation value of the received signal on each beam.

[0027] An embodiment of the present invention further provides a computer-readable storage medium on which a computer program is stored. When the computer program is executed by a processor, the steps of the method for determining the frequency deviation value of the signal are executed.

[0028] An embodiment of the present invention further provides a terminal, including a memory and a processor, wherein the memory stores a computer program that can be run on the processor, and the processor executes the steps of the above-mentioned method for determining the frequency deviation value of the signal when running the computer program.

[0029] Compared with the prior art, the technical solution of the embodiment of the present invention has the following beneficial effects:

[0030] In an embodiment of the present invention, multiple antennas are used to receive multiple received signals, and the multiple received signals received by each antenna have respective arrival times and arrival angles; the multiple received signals received by the multiple antennas are beam decomposed to obtain received signals on multiple beams, and the multiple received signals on each beam have respective arrival times and belong to the same arrival angle interval; frequency deviation estimation is performed on the received signal on each beam to obtain frequency deviation values ​​of the received signals on each beam. Compared with the prior art, the method of estimating the Doppler frequency deviation value by using the phase information of the correlation values ​​and the time interval of the correlation values ​​between the received signals with a certain time interval is only applicable to the signal in a single wave direction. When the received signal arrives at the receiving end with multiple arrival angles, the calculation process is time-consuming and cumbersome, and the accuracy is insufficient. The embodiment of the present invention adopts multiple antennas to respectively receive signals in multiple arrival angle directions, and then performs beam decomposition on the received signal. The received signals on each beam after decomposition belong to the same arrival angle interval (that is, the arrival angle values ​​of each received signal on each beam are similar). Then, the frequency deviation value of the received signal on each beam is calculated respectively. The above technical solution is helpful to quickly and accurately determine the frequency deviation values ​​of the received signals in multiple different arrival angle directions.

[0031] Furthermore, after obtaining the frequency deviation value of the received signal on each beam, the method further includes: performing frequency deviation correction on the received signal on each beam according to the frequency deviation value of the received signal on each beam. In addition, the Doppler spread spectrum is determined according to the frequency deviation value and power mean of the received signal on each beam. In an embodiment of the present invention, after determining the frequency deviation value of the received signal on each beam belonging to different arrival angle intervals, frequency deviation correction can be performed according to the needs of the actual application scenario, the Doppler spread spectrum can be determined, and then the channel estimation can be calculated (for example, according to the Doppler spread spectrum, the channel estimation value after the minimum mean square error MMSE filtering in the time domain is calculated). BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 is a flow chart of a method for determining a frequency deviation value of a signal in an embodiment of the present invention;

[0033] Figure 2 yes Figure 1 A flowchart of a specific implementation of step S13;

[0034] Figure 3 is a flow chart of another method for determining a frequency deviation value of a signal in an embodiment of the present invention;

[0035] Figure 4 is a flow chart of a method for determining a frequency deviation value of a signal in another embodiment of the present invention;

[0036] Figure 5 is a schematic diagram of a Doppler spread spectrum in an embodiment of the present invention;

[0037] Figure 6 It is a structural schematic diagram of a device for determining a frequency deviation value of a signal in an embodiment of the present invention. DETAILED DESCRIPTION

[0038] As mentioned above, in signal transmission, the Doppler effect is generated due to the relative motion between the transmitter and the receiver. When the electromagnetic wave signal reaches the receiver at multiple different arrival angles, multiple Doppler frequency shifts will occur, and the spectrum of the received signal will be broadened. By determining the frequency deviation value of the received signal, the signal can be corrected for frequency deviation and the Doppler spread spectrum can be determined, which can then be applied in a wider range of applications.

[0039] In the prior art, for a signal with only one incoming wave direction, since Doppler expansion does not occur (i.e., a collection of multiple different Doppler frequency shifts does not occur), a common technique for determining the frequency deviation value of the received signal is: using received signals with a certain time interval, compensating for the phase influence of their corresponding transmitted signals, and then calculating the correlation values ​​between the received signals pairwise, and using the phase information of the correlation values ​​and their time interval to estimate the signal frequency deviation value.

[0040] The inventors of the present invention have found through research that if the received signal arrives at multiple arrival angles, it may take a longer time to receive the signal for frequency offset estimation, and some complex frequency offset estimation algorithms need to be used. The calculation process is time-consuming and cumbersome, and the accuracy is insufficient.

[0041] In an embodiment of the present invention, multiple antennas are used to receive multiple received signals, and the multiple received signals received by each antenna have their own arrival time and arrival angle; the multiple received signals received by the multiple antennas are beam decomposed to obtain received signals on multiple beams, and the multiple received signals on each beam have their own arrival time and belong to the same arrival angle interval; the received signals on each beam are frequency offset estimated to obtain the frequency offset value of the received signals on each beam. Compared with the prior art, the method of estimating the Doppler frequency offset value based on the phase information and time interval of the correlation value between the received signals with a certain time interval is often used, which is only applicable to signals in a single direction of arrival. When the received signal arrives at multiple arrival angles, the calculation process is time-consuming and cumbersome, and the accuracy is insufficient; the embodiment of the present invention uses multiple antennas to receive signals in multiple arrival angle directions respectively, and then beam decomposes the received signals, and the received signals on each beam after decomposition belong to the same arrival angle interval, and then the frequency offset values ​​of the received signals on each beam are calculated respectively. The above technical solution helps to quickly and accurately determine the frequency offset values ​​of received signals in multiple different arrival angle directions.

[0042] In order to make the above-mentioned objects, features and beneficial effects of the present invention more obvious and understandable, specific embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0043] Reference Figure 1 , Figure 1 1 is a flow chart of a method for determining a frequency deviation value of a signal in an embodiment of the present invention. The method may include steps S11 to S13:

[0044] Step S11: using multiple antennas to receive multiple reception signals, the multiple reception signals received by each antenna having respective arrival times and arrival angles;

[0045] Step S12: performing beam decomposition on the multiple reception signals received by the multiple antennas to obtain reception signals on multiple beams, wherein the multiple reception signals on each beam have respective arrival times and belong to the same arrival angle interval;

[0046] Step S13: performing frequency offset estimation on the received signal on each beam to obtain the frequency offset value of the received signal on each beam.

[0047] It is understandable that, in a specific implementation, the method can be implemented in the form of a software program, which runs in a processor integrated inside a chip or a chip module; or, the method can be implemented in the form of hardware or a combination of hardware and software.

[0048] In the specific implementation of step S11, the multiple received signals may be signals when the electromagnetic wave signals emitted by the base station, vehicle-mounted terminal, mobile phone, computer, tablet, etc. arrive at the receiving end after being transmitted through the wireless channel. Specifically, due to the complexity of the actual wireless channel path, a transmitted signal may arrive at the receiving end at multiple arrival angles after being transmitted through the wireless channel. The arrival angle may refer to the angle between the wave ray and a certain direction (horizontal plane or horizontal plane normal), which can also be called the angle of incidence. Specifically, the arrival angle of the received signal may be the angle between the electromagnetic wave ray and the normal direction of the antenna array.

[0049] In a specific implementation, after the electromagnetic wave signal is sent out, since the propagation path between the transmitting end and the receiving end is often very complex and may encounter various obstacles such as mountains, trees, and buildings, the electromagnetic wave signal may be transmitted to the multiple antennas through a wireless channel with very rich multipath components and receiving arrival angles in all directions. In this case, the multiple received signals received by each antenna have their own arrival time and arrival angle. When there is relative motion between the transmitting end and the receiving end, multiple Doppler frequency shifts will be generated due to the Doppler effect, and the spectrum of the received signal will be broadened.

[0050] In a specific implementation, when multiple antennas are used to receive the multiple received signals, the multiple antennas may be arranged in an array (including but not limited to a linear array, a planar array, and a spherical array). When the antennas are arranged in a linear array or a planar array, in order to avoid being unable to distinguish received signals with different arrival angles, the arrangement direction of the multiple antennas is parallel to the moving direction of the antenna array, and the spacing between adjacent antennas is less than half of the carrier wavelength of the transmitted signal. For some antenna arrays, it is possible that every two / multiple antennas are located at the same position, and the spacing between the positions of the two / multiple antennas and the positions of the other two / multiple antennas adjacent to each other is less than half of the carrier wavelength of the transmitted signal. Among them, the moving direction of the antenna array may refer to the moving direction of the carrier of the antenna, and the carrier of the antenna may be a vehicle-mounted receiver, a radio, a mobile phone, and the like.

[0051] In the specific implementation of step S12, beam decomposition is performed on the multiple received signals received by the multiple antennas, and beam decomposition can be performed on the multiple received signals received by all or part of the multiple antennas within a preset time length. Specifically, the peak directions of the beams of the multiple received signals can be aligned with the estimated arrival angle directions, so that the received signals on the multiple antennas are converted into received signals on multiple beams, and the received signals on each beam have their own arrival time and belong to the same arrival angle range (that is, the arrival angle values ​​of the multiple received signals on each beam are similar).

[0052] Further, performing beam decomposition on the multiple reception signals received by the multiple antennas to obtain reception signals on multiple beams includes: performing orthogonal beam decomposition on the multiple reception signals received by the multiple antennas to obtain reception signals on all or part of the beams.

[0053] In short, the orthogonal beam decomposition is to add all the orthogonal beam directions together to cover all angles, and obtain the received signals on all orthogonal beams. In a specific implementation, the specific method of the orthogonal beam decomposition can be a conventional method used in the prior art, which will not be repeated here.

[0054] Furthermore, performing orthogonal beam decomposition on the multiple received signals received by the multiple antennas to obtain received signals on some beams includes: performing orthogonal beam decomposition on the multiple received signals received by the multiple antennas, and calculating the signal-to-noise ratio mean and energy mean of the multiple received signals on each of the beams obtained; and selecting a beam whose signal-to-noise ratio mean is greater than a first preset threshold or whose energy mean is greater than a second preset threshold to obtain the received signals on the partial beams.

[0055] In a specific implementation, all orthogonal beam directions can be added together to cover all angles, and after obtaining the received signals on all orthogonal beams, the signal-to-noise ratio mean and energy mean of the multiple received signals on each beam obtained are calculated, and then the beams whose signal-to-noise ratio mean is greater than a first preset threshold or whose energy mean is greater than a second preset threshold are screened to obtain the received signals on the partial beams. The signal-to-noise ratio (SNR) can be used to indicate the ratio of the signal to the noise in the received signal, and the unit of measurement of the signal-to-noise ratio is decibel (dB). The higher the signal-to-noise ratio, the more reliable the signal.

[0056] Furthermore, beam decomposition is performed on the multiple received signals received by the multiple antennas to obtain received signals on multiple beams, including: using an arrival angle estimation algorithm to estimate the arrival angles of the multiple received signals received by the multiple antennas to obtain multiple arrival angles, and then aligning the peak directions of the beams of the multiple received signals with the estimated arrival angle directions to obtain the received signals on the multiple beams.

[0057] In some non-limiting embodiments, the arrival angle estimation algorithm may be selected from Bartlett algorithm, Capon algorithm, and multiple signal classification MUSIC algorithm; other existing arrival angle estimation algorithms may also be selected, which is not limited in the embodiments of the present invention.

[0058] It should be pointed out that the beam decomposition method described above is only a non-limiting embodiment. In a specific implementation, other existing suitable beam decomposition methods can also be used to perform beam decomposition on the multiple received signals received by the multiple antennas, which will not be repeated here.

[0059] In the specific implementation of step S13, the frequency offset of the received signal on each beam is estimated to obtain the frequency offset value of the received signal on each beam.

[0060] In a specific implementation, as described above, after beam decomposition is performed on the multiple received signals received by the multiple antennas, the received signals on the multiple antennas are converted into received signals on multiple beams, and then the frequency offset of the received signals on each beam is estimated. Since the multiple received signals on each beam obtained after decomposition belong to the same arrival angle interval (the arrival angle values ​​are similar), the Doppler spread is not serious, so only one frequency offset value can be estimated for the received signal on each beam.

[0061] In an embodiment of the present invention, compared with the prior art method of estimating the Doppler frequency deviation value by using the phase information of the correlation values ​​and the time interval of the correlation values ​​between the received signals with a certain time interval, which is only applicable to the signal of a single wave direction, and when the received signal arrives at the receiving end with multiple arrival angles, the calculation process may be very time-consuming and cumbersome, and the accuracy is insufficient; the embodiment of the present invention adopts multiple antennas to respectively receive signals in multiple arrival angle directions, and then performs beam decomposition on the multiple received signals. The received signals on each beam after decomposition belong to the same arrival angle interval, and then the frequency deviation values ​​of the received signals on each beam are estimated respectively, thereby helping to quickly and accurately determine the frequency deviation values ​​of the received signals in multiple different arrival angle directions.

[0062] Reference Figure 2 , Figure 2 yes Figure 1 The flowchart of the specific implementation of step S13 in the embodiment of the present invention. The frequency offset estimation of the received signal on each beam to obtain the frequency offset value of the received signal on each beam may include steps S21 to S22, which are described below.

[0063] In step S21, for each beam, a correlation value between every two received signals corresponding to different transmission times among a plurality of received signals on the beam is calculated, and an initial frequency offset value is calculated according to the correlation value.

[0064] The correlation value is used to indicate the correlation degree between the received signals at different transmission times. The larger the correlation value, the higher the correlation degree between the two received signals; the smaller the correlation, the lower the correlation degree between the two received signals.

[0065] In step S22, the frequency offset value of the received signal on the beam is determined according to the obtained multiple initial frequency offset values.

[0066] Further, for each beam, the following formula is used to calculate the correlation value of each two received signals corresponding to different transmission times among the multiple received signals on the beam, and the initial frequency offset value is calculated according to the correlation value:

[0067] R=r(t0)×s*(t0)×r*(t1)×s(t1);

[0068]

[0069] Among them, f d is used to indicate the initial frequency deviation value; R is used to indicate the correlation value between two signals; angle() is used to indicate the phase angle function of the complex number; r(t0) is used to indicate the received signal with the transmission time t0 on a certain beam; r *(t1) is used to indicate the conjugate complex number of the received signal at the transmission time t1 on a certain beam; s*(t0) is used to indicate the conjugate complex number of the transmitted signal s(t0) corresponding to r(t0); s(t1) is used to indicate the transmitted signal corresponding to r(t1); where t1>t0 and satisfies

[0070] Further, in some non-limiting embodiments, for each beam, the average value of the multiple initial frequency deviation values ​​obtained can be used as the frequency deviation value of the received signal on the beam; the median value of the multiple initial frequency deviation values ​​obtained can also be used as the frequency deviation value of the received signal on the beam; different weights can also be assigned to the calculated initial frequency deviation values ​​according to the signal-to-noise ratio or energy extreme value of each received signal on the beam, and then a weighted operation is performed to determine the frequency deviation value of the received signal on the beam. In a specific implementation, other suitable methods can also be used to determine the frequency deviation value of the received signal on each beam, and the embodiments of the present invention are not limited to this.

[0071] In the specific implementation, for more details about steps S21 to S22, please refer to the above and Figure 1 The steps described in the procedure are executed and will not be repeated here.

[0072] Reference Figure 3 , Figure 3 1 is a flow chart of another method for determining a frequency deviation value of a signal in an embodiment of the present invention. The method for determining a frequency deviation value of another signal may include steps S31 to S35, and each step is described below.

[0073] In step S31, multiple antennas are used to receive multiple reception signals, and the multiple reception signals received by each antenna have respective arrival times and arrival angles.

[0074] In step S32, orthogonal beam decomposition is performed on the multiple reception signals received by the multiple antennas to obtain reception signals on all or part of the beams, wherein the multiple reception signals on each beam have respective arrival times and belong to the same arrival angle interval.

[0075] In step S33, for each beam, a correlation value between every two received signals corresponding to different transmission times among a plurality of received signals on the beam is calculated, and an initial frequency offset value is calculated based on the correlation value.

[0076] In step S34, the frequency offset value of the received signal on the beam is determined according to the obtained multiple initial frequency offset values.

[0077] In step S35, frequency offset correction is performed on the received signal on each beam according to the frequency offset value of the received signal on each beam.

[0078] In a specific implementation, the frequency offset correction can adopt a conventional frequency offset correction method in the prior art, such as method 1: using time domain multiplication by linear phase factor compensation; method 2: using frequency domain convolution to correct the frequency offset. After obtaining the corrected received signal, a pilot signal can be extracted from it, and then channel estimation is performed based on the pilot signal.

[0079] In the embodiment of the present invention, after the electromagnetic wave signal emitted by the transmitting end is transmitted to the moving receiving end through the wireless channel, the received signals in each arrival angle direction may produce frequency deviation, so the original spectrum of the received signal (the signal spectrum when the transmitting end sends it) and the Doppler spectrum after the frequency deviation may be convolved with each other, that is, the time domain waveform of its original spectrum is multiplied by the time domain waveform transformation of the Doppler spectrum, so that the signal is attenuated in the time domain. By adopting the above technical scheme, the received signals on multiple antennas can be converted into received signals on multiple beams, and the received signals on each beam belong to the same arrival angle interval (the arrival angle values ​​are similar); then determine the frequency deviation value of the received signal on each beam; then according to the frequency deviation value of the received signal on each beam, correct the frequency deviation of the received signal on each beam, so as to help make the frequency value of the received signal close to the original frequency value of the signal emitted by the transmitting end, and restore the original information carried by the signal emitted by the transmitting end as much as possible.

[0080] In the specific implementation, for more details about steps S31 to S35, please refer to the above and Figure 1 , Figure 2 The steps described in the procedure are executed and will not be repeated here.

[0081] Reference Figure 4 , Figure 4 4 is a flow chart of another method for determining a frequency deviation value of a signal in an embodiment of the present invention. The method for determining a frequency deviation value of a signal may include steps S41 to S45, and each step is described below.

[0082] In step S41, multiple antennas are used to receive multiple reception signals, and the multiple reception signals received by each antenna have respective arrival times and arrival angles.

[0083] In step S42, beam decomposition is performed on the multiple reception signals received by the multiple antennas to obtain reception signals on multiple beams, wherein the multiple reception signals on each beam have respective arrival times and belong to the same arrival angle interval.

[0084] In step S43, frequency offset estimation is performed on the received signal on each beam to obtain the frequency offset value of the received signal on each beam.

[0085] In step S44, the Doppler spread spectrum is determined according to the frequency offset value and the power average value of the received signal on each beam.

[0086] Reference Figure 5 , Figure 5 Schematic diagram of a Doppler spread spectrum in an embodiment of the present invention. The Doppler spread spectrum can be used to reflect the relationship between the frequency value and the power mean value of the received signal on each beam.

[0087] In the specific implementation, it is assumed that the transmitter sends a frequency of f c A single-frequency sine wave passes through a wireless channel with rich multipath components and receiving arrival angles in all directions. If the aforementioned Doppler effect occurs due to relative motion, the spectrum of the received signal will be broadened and will contain a frequency of f c -f m ~f c +f m This spectrum is the Doppler spread spectrum.

[0088] In the Doppler spread spectrum, the horizontal axis is the frequency value (f) of the received signal on each beam, and the vertical axis is the power mean value (S) of the received signal on each beam. Ez ), f c Represents the original frequency value of the electromagnetic wave signal emitted by the transmitter, f m It indicates the maximum frequency deviation value generated after the electromagnetic wave signal undergoes Doppler frequency shift. For the received signal on each beam, there is a unique frequency deviation value, and the maximum frequency deviation value is the largest value among the frequency deviation values ​​of each beam.

[0089] Continue to refer to Figure 4 In step S45, a channel estimation value after time-domain minimum mean square error MMSE filtering is calculated according to the Doppler spread spectrum.

[0090] Further, the following formula is used to calculate the channel estimation value after time domain minimum mean square error MMSE filtering according to the Doppler spread spectrum:

[0091] H t′mmse (l) = R H′H ×(R HH +σ 2 l) -1 ×H LS ;

[0092] Among them, H t′mmse (l) is used to indicate the channel estimation value after time-domain MMSE filtering of the lth OFDM symbol; R HH N is used to indicate time domain contiguous tfiltThe first channel correlation matrix of OFDM symbols containing pilots is N tfilt ×N tfilt ; R H′H Used to indicate the relationship between the lth OFDM symbol and the N nearest OFDM symbol. tfilt The second channel correlation matrix of OFDM symbols containing pilots is 1×N tfilt ;H Ls Used to indicate the N nearest to the lth OFDM symbol tfilt The matrix of channel estimates before time-domain MMSE filtering of OFDM symbols containing pilots is N tfilt ×1; where N tfilt Used to indicate the order of the time domain MMSE filter; σ 2 To indicate H LS The noise power on .

[0093] In a specific implementation, the Doppler spread spectrum can be inversely Fourier transformed to obtain the corresponding channel time domain correlation spectrum; the first channel correlation matrix R can be obtained according to the channel time domain correlation spectrum. HH and the second channel correlation matrix R H′H ; and / or according to the frequency offset value of the received signal on each beam, the received signal on each beam is corrected for frequency offset to obtain a corrected signal; the OFDM symbol containing the pilot is extracted from the corrected signal, and then the channel estimation is performed according to the OFDM symbol containing the pilot to obtain the matrix H of the channel estimation value before the time domain MMSE filtering LS Other suitable methods in the prior art may also be used to determine the aforementioned matrices, which is not limited in the embodiment of the present invention.

[0094] In an embodiment of the present invention, after determining the frequency deviation value of the received signal on each beam corresponding to different arrival angles, the Doppler spread spectrum can be determined, and then the channel estimation value after the minimum mean square error MMSE filtering in the time domain can be calculated according to the needs of the actual application scenario, and then the multiple-in multiple-out (MIMO) system is used for equalization processing.

[0095] Among them, the MIMO system is to increase the channel capacity, using multiple antennas at both the transmitting and receiving ends, forming an antenna system with multiple channels between the transmitting and receiving ends. An obvious feature of the MIMO system is its extremely high spectrum utilization efficiency.

[0096] In the specific implementation, for more details about steps S41 to S45, please refer to the above and Figures 1 to 3 The steps described in the procedure are executed and will not be repeated here.

[0097] Reference Figure 6 , Figure 6 1 is a schematic diagram of a structure of a device for determining a frequency deviation value of a signal in an embodiment of the present invention. The device may include:

[0098] The signal receiving module 61 is used to receive multiple receiving signals using multiple antennas, and the multiple receiving signals received by each antenna have their own arrival time and arrival angle;

[0099] A beam decomposition module 62, configured to perform beam decomposition on the multiple received signals received by the multiple antennas to obtain received signals on multiple beams, wherein the multiple received signals on each beam have respective arrival times and belong to the same arrival angle interval;

[0100] The frequency offset value determination module 63 is used to estimate the frequency offset of the received signal on each beam to obtain the frequency offset value of the received signal on each beam.

[0101] For the principle, specific implementation and beneficial effects of the signal frequency deviation value determination device, please refer to the previous article and Figures 1 to 5 The related description about the method for determining the frequency deviation value of the signal shown is not repeated here.

[0102] In a specific implementation, the above-mentioned device for determining the frequency deviation value of a signal may correspond to a chip having a function of determining the frequency deviation value of a signal; or correspond to a chip module having a function of determining the frequency deviation value of a signal in a terminal, or correspond to a terminal.

[0103] The embodiment of the present invention further provides a computer-readable storage medium on which a computer program is stored, and when the computer program is executed by a processor, the steps of the method for determining the frequency deviation value of the above signal are executed. The computer-readable storage medium may include a non-volatile memory or a non-transitory memory, and may also include an optical disk, a mechanical hard disk, a solid-state hard disk, etc.

[0104] Specifically, in the embodiment of the present invention, the processor may be a central processing unit (CPU), and the processor may also be other general-purpose processors, digital signal processors (DSP), application specific integrated circuits (ASIC), field programmable gate arrays (FPGA), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. A general-purpose processor may be a microprocessor or the processor may also be any conventional processor, etc.

[0105] It should also be understood that the memory in the embodiments of the present application may be a volatile memory or a non-volatile memory, or may include both volatile and non-volatile memories. Among them, the non-volatile memory may be a read-only memory (ROM), a programmable read-only memory (PROM), an erasable programmable read-only memory (EPROM), an electrically erasable programmable read-only memory (EEPROM), or a flash memory. The volatile memory may be a random access memory (RAM), which is used as an external cache. By way of example but not limitation, many forms of random access memory (RAM) are available, such as static RAM (SRAM), dynamic random access memory (DRAM), synchronous DRAM (SDRAM), double data rate synchronous dynamic random access memory (DDR SDRAM), enhanced synchronous dynamic random access memory (ESDRAM), synchronous link DRAM (SLDRAM) and direct rambus RAM (DR RAM).

[0106] The embodiment of the present invention further provides a terminal, including a memory and a processor, wherein the memory stores a computer program that can be run on the processor, and the processor executes the steps of the method for determining the frequency deviation value of the above signal when running the computer program. The terminal may include but is not limited to terminal devices such as mobile phones, computers, and tablet computers, and may also be a server, a cloud platform, and the like.

[0107] The above embodiments may be implemented in whole or in part by software, hardware, firmware or any other combination thereof. When implemented using software, the above embodiments may be implemented in whole or in part in the form of a computer program product. The computer program product includes one or more computer instructions or computer programs. When the computer instructions or computer programs are loaded or executed on a computer, the processes or functions described in the embodiments of the present application are generated in whole or in part. The computer may be a general-purpose computer, a special-purpose computer, a computer network, or other programmable devices. The computer program may be stored in a computer-readable storage medium, or may be transmitted from one computer-readable storage medium to another computer-readable storage medium, for example, the computer program may be transmitted from one website, computer, server or data center to another website, computer, server or data center by wired or wireless means.

[0108] In the several embodiments provided in the present application, it should be understood that the disclosed methods, devices and systems can be implemented in other ways. For example, the device embodiments described above are merely schematic; for example, the division of the units is only a logical function division, and there may be other division methods in actual implementation; for example, multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. The units described as separate components may or may not be physically separated, and the components displayed as units may or may not be physical units, that is, they may be located in one place, or they may be distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the scheme of this embodiment.

[0109] In addition, each functional unit in each embodiment of the present invention may be integrated into one processing unit, or each unit may be physically included separately, or two or more units may be integrated into one unit. The above-mentioned integrated unit may be implemented in the form of hardware or in the form of hardware plus software functional units. For example, for each device or product applied to or integrated in a chip, each module / unit contained therein may be implemented in the form of hardware such as circuits, or at least part of the modules / units may be implemented in the form of software programs, which run on a processor integrated inside the chip, and the remaining (if any) modules / units may be implemented in the form of hardware such as circuits; for each device or product applied to or integrated in a chip module, each module / unit contained therein may be implemented in the form of hardware such as circuits, and different modules / units may be located in the same component (such as a chip, circuit module, etc.) or different components of the chip module, or at least part of the modules / units may be implemented in the form of software programs. The element can be implemented in the form of a software program, which runs on a processor integrated inside the chip module, and the remaining (if any) modules / units can be implemented in the form of hardware such as circuits; for various devices and products applied to or integrated in the terminal, the various modules / units contained therein can be implemented in the form of hardware such as circuits, and different modules / units can be located in the same component (for example, chip, circuit module, etc.) or in different components in the terminal, or, at least some modules / units can be implemented in the form of a software program, which runs on a processor integrated inside the terminal, and the remaining (if any) modules / units can be implemented in the form of hardware such as circuits.

[0110] It should be understood that the term "and / or" in this article is only a description of the association relationship of the associated objects, indicating that there can be three relationships. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in this article indicates that the associated objects before and after are in an "or" relationship.

[0111] The "plurality" appearing in the embodiments of the present application refers to two or more.

[0112] The first, second, etc. descriptions appearing in the embodiments of the present application are only used for illustration and distinction of the description objects. There is no order, nor do they indicate any special limitation on the number of devices in the embodiments of the present application, and cannot constitute any limitation on the embodiments of the present application.

[0113] It should be pointed out that the serial numbers of the steps in this embodiment do not limit the execution order of the steps.

[0114] Although the present invention is disclosed as above, the present invention is not limited thereto. Any person skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the scope defined by the claims.

Claims

1. A method for determining a frequency deviation value of a signal, characterized in that: include: Using multiple antennas to receive multiple reception signals, the multiple reception signals received by each antenna have respective arrival times and arrival angles, the spacing between adjacent positions of the multiple antennas is less than half of the carrier wavelength of the transmission signal, and the arrangement direction of the multiple antennas on the receiver is parallel to the movement direction of the receiver; Performing beam decomposition on the multiple reception signals received by the multiple antennas to obtain reception signals on multiple beams, wherein the multiple reception signals on each beam have respective arrival times and belong to the same arrival angle interval; Performing frequency offset estimation on the received signal on each beam to obtain the frequency offset value of the received signal on each beam; The step of estimating the frequency offset of the received signal on each beam to obtain the frequency offset value of the received signal on each beam includes: For each beam, calculating a correlation value between each two received signals corresponding to different transmission times among a plurality of received signals on the beam, and calculating an initial frequency offset value according to the correlation value; The frequency offset value of the received signal on the beam is determined according to the obtained multiple initial frequency offset values.

2. The method according to claim 1, characterized in that The method further comprises: According to the frequency deviation value of the received signal on each beam, the frequency deviation of the received signal on each beam is corrected.

3. The method according to claim 1, characterized in that Performing beam decomposition on the multiple reception signals received by the multiple antennas to obtain reception signals on multiple beams includes: Orthogonal beam decomposition is performed on the multiple reception signals received by the multiple antennas to obtain reception signals on all or part of the beams.

4. The method according to claim 3, characterized in that Performing orthogonal beam decomposition on the multiple reception signals received by the multiple antennas to obtain reception signals on some beams includes: Performing orthogonal beam decomposition on the multiple received signals received by the multiple antennas, and calculating the signal-to-noise ratio mean and energy mean of the multiple received signals on each of the obtained beams; Select beams whose signal-to-noise ratio mean is greater than a first preset threshold or whose energy mean is greater than a second preset threshold to obtain received signals on the partial beams.

5. The method according to claim 1, characterized in that Performing beam decomposition on the multiple reception signals received by the multiple antennas to obtain reception signals on multiple beams includes: An arrival angle estimation algorithm is used to estimate the arrival angles of the multiple received signals received by the multiple antennas to obtain multiple arrival angles, and then the peak directions of the beams of the multiple received signals are aligned with the estimated arrival angle directions to obtain the received signals on the multiple beams.

6. The method according to claim 5, characterized in that The arrival angle estimation algorithm is selected from: Bartlett algorithm, Capon algorithm, MUSIC algorithm.

7. The method according to claim 1, characterized in that For each beam, the following formula is used to calculate the correlation value of each two received signals corresponding to different transmission times among the multiple received signals on the beam, and the initial frequency offset value is calculated according to the correlation value: R=r(t0)×s*(t0)×r*(t1)×s(t1); Among them, f d Used to indicate the initial frequency deviation value; R is used to indicate the correlation value between the two signals; angle() is used to indicate the phase angle solution function of the complex number; r(t0) is used to indicate the received signal on a certain beam with the transmission time t0; r*(t1) is used to indicate the conjugate complex number of the received signal on a certain beam with the transmission time t1; s*(t0) is used to indicate the conjugate complex number of the transmitted signal s(t0) corresponding to r(t0); s(t1) is used to indicate the transmitted signal corresponding to r(t1); wherein t1>t0, and satisfies 8. The method according to claim 1, characterized in that Determining the frequency offset value of the received signal on the beam according to the obtained multiple initial frequency offset values ​​includes: The average value of the obtained multiple initial frequency offset values ​​is used as the frequency offset value of the received signal on the beam; or, The median value of the obtained multiple initial frequency offset values ​​is used as the frequency offset value of the received signal on the beam.

9. The method according to claim 1, characterized in that: After obtaining the frequency deviation value of the received signal on each beam, the method further includes: The Doppler spread spectrum is determined based on the frequency deviation value and power average of the received signal on each beam.

10. The method according to claim 9, characterized in that The method further comprises: According to the Doppler spread spectrum, a channel estimation value after time-domain minimum mean square error MMSE filtering is calculated.

11. The method according to claim 10, characterized in that The channel estimation value after time domain minimum mean square error MMSE filtering is calculated according to the Doppler spread spectrum using the following formula: H t'mmse (l)=R H'H ×(R HH +s 2 l) -1 ×H LS ; Among them, H t'mmse (l) is used to indicate the channel estimation value after time-domain MMSE filtering of the lth OFDM symbol; R HH N is used to indicate time domain contiguous tfilt The first channel correlation matrix of OFDM symbols containing pilots is N tfilt ×N tfilt ; R H'H Used to indicate the relationship between the lth OFDM symbol and the N nearest OFDM symbol. tfilt The second channel correlation matrix of OFDM symbols containing pilots is 1×N tfilt ;H LS Used to indicate the N nearest to the lth OFDM symbol tfilt A matrix of channel estimates before time-domain MMSE filtering containing pilot OFDM symbols, with a dimension of N tfilt ×1; where N tfilt Used to indicate the order of the time domain MMSE filter; σ 2 To indicate H LS The noise power on .

12. The method according to claim 1, characterized in that The multiple antennas are arranged in an array.

13. The method according to claim 12, characterized in that The multiple antennas are arranged in an array and satisfy one or more of the following: The multiple antennas are arranged in a linear array; The multiple antennas are arranged in a planar array; The multiple antennas are arranged in a spherical array.

14. A device for determining a frequency deviation value of a signal, characterized in that: include: A signal receiving module, configured to receive multiple reception signals using multiple antennas, wherein the multiple reception signals received by each antenna have respective arrival times and arrival angles, the spacing between adjacent positions of the multiple antennas is less than half of the carrier wavelength of the transmitted signal, and the arrangement direction of the multiple antennas on the receiver is parallel to the movement direction of the receiver; A beam decomposition module, used for performing beam decomposition on the multiple reception signals received by the multiple antennas to obtain reception signals on multiple beams, wherein the multiple reception signals on each beam have respective arrival times and belong to the same arrival angle interval; A frequency deviation value determination module, used to estimate the frequency deviation of the received signal on each beam to obtain the frequency deviation value of the received signal on each beam; Wherein, the frequency offset value determination module further executes: For each beam, calculating a correlation value between each two received signals corresponding to different transmission times among a plurality of received signals on the beam, and calculating an initial frequency offset value according to the correlation value; The frequency offset value of the received signal on the beam is determined according to the obtained multiple initial frequency offset values.

15. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the method for determining the frequency deviation value of a signal according to any one of claims 1 to 13 are executed.

16. A terminal comprising a memory and a processor, wherein the memory stores a computer program that can be run on the processor, characterized in that: When the processor runs the computer program, the processor performs the steps of the method for determining the frequency deviation value of the signal according to any one of claims 1 to 13.

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