Channel calibration method and device
Technical Field
The present invention relates to the field of communications technologies, and in particular, to a method and an apparatus for channel calibration.
Background
In a system of a transmitting and receiving loop in the intelligent multi-antenna technology, different antennas generate certain delay errors in the transmitting and receiving processes, and taking an eight-channel radio Remote unit (radio Remote unit) as an example, different antennas of the eight antennas of the RRU generate certain delay errors in the transmitting and receiving processes. And the amplitude and phase characteristics of each antenna channel may be inconsistent due to changes in time, temperature, environment, and aging of the device.
In the existing channel calibration technology, a calibration filter is added to each channel to eliminate the difference between the channels. However, the signal still has a certain time delay when passing through the filter. The time delay compensation method of the calibration filter adopts time domain impulse response shift time delay at 0 moment to perform time delay compensation on signals passing through the calibration filter. In practical applications, the time domain impulse response shift delay at time 0 cannot completely match the delay generated by the calibration filter, that is, there is still a delay adjustment error.
It can be seen that the multi-channel RRU calibration accuracy in the prior art is low.
Disclosure of Invention
The embodiment of the invention provides a method and a device for calibrating channels, which are used for solving the technical problem of low calibration precision of multi-channel RRU in the prior art and improving the calibration precision of the multi-channel RRU.
In one aspect, an embodiment of the present invention provides a channel calibration method, which is applied to a multi-channel radio remote unit RRU, where the multi-channel includes a channel to be calibrated and a reference channel, and includes:
acquiring a calibration sequence of the channel to be calibrated and a calibration sequence of the reference channel;
calculating calibration filter coefficients of the channel to be calibrated by using a frequency domain response between the calibration sequence of the reference channel and the calibration sequence of the channel to be calibrated, wherein the calibration filter coefficients are used for characterizing a calibration filter of the channel to be calibrated;
obtaining a time delay compensation value of the calibration filter by using the calibration filter coefficient;
obtaining a first time delay value of the channel to be calibrated by utilizing the autocorrelation of the calibration sequence of the channel to be calibrated, and obtaining a second time delay value of the reference channel by utilizing the autocorrelation of the calibration sequence of the reference channel;
and obtaining the time delay difference between the channel to be calibrated and the reference channel based on the time delay compensation value of the calibration filter, the first time delay value and the second time delay value, and performing time delay compensation on the channel to be calibrated.
Optionally, the calculating a calibration filter coefficient of the channel to be calibrated by using a frequency domain response between the calibration sequence of the reference channel and the calibration sequence of the channel to be calibrated specifically includes:
carrying out frequency domain transformation on the calibration sequence of the channel to be calibrated, and carrying out frequency domain transformation on the calibration sequence of the reference channel;
obtaining a ratio between the frequency domain transformation of the reference channel and the frequency domain transformation of the channel to be calibrated, wherein the ratio is the frequency domain response between the reference channel and the channel to be calibrated;
carrying out Fourier inversion on the frequency domain response to obtain a calibration factor between the reference channel and the channel to be calibrated;
and obtaining the calibration filter coefficient of the channel to be calibrated based on the calibration factor.
Optionally, the obtaining a calibration filter coefficient of the channel to be calibrated based on the calibration factor specifically includes:
determining M maximum impulse response points corresponding to the calibration factor, wherein the M maximum impulse response points are specifically the calibration filter coefficients, and M is a positive integer;
the obtaining of the delay compensation value of the calibration filter by using the calibration filter coefficient specifically includes:
obtaining M-order tap delay values based on the M maximum impulse response points;
and summing the M-order tap time delay values to obtain the time delay compensation value of the calibration filter.
Optionally, after obtaining the calibration filter coefficients of the channel to be calibrated based on the calibration factor, the method further includes:
obtaining a correlation signal;
carrying out convolution multiplication on the correlation signal and the calibration factor to obtain a convolution result;
performing conjugate correlation on the convolution result and the correlation signal;
determining the position information of the highest peak point related to conjugation;
and obtaining a time delay compensation value of the calibration filter based on the position information.
Optionally, the obtaining the first delay value of the channel to be calibrated by using the autocorrelation of the calibration sequence, and obtaining the second delay value of the reference channel by using the autocorrelation of the calibration sequence of the reference channel specifically include:
obtaining a local sequence;
performing conjugate correlation on the calibration sequence of the channel to be calibrated and the local sequence, determining first position information where a highest peak point of the conjugate correlation is located, and performing conjugate correlation on the calibration sequence of the reference channel and the local sequence, and determining second position information where the highest peak point of the conjugate correlation is located;
obtaining the first time delay value of the channel to be calibrated based on the first position information, and obtaining the second time delay value of the reference channel based on the second position information.
Optionally, after obtaining the delay difference between the channel to be calibrated and the reference channel based on the delay compensation value of the calibration filter, the first delay value, and the second delay value, the method further includes:
and calibrating the channel to be calibrated based on the time delay difference so that the time delay value of the signal calibrated by the channel to be calibrated is the same as the second time delay value of the reference channel.
On the other hand, an embodiment of the present invention further provides a device for calibrating a channel, which is applied to a multi-channel radio remote unit RRU, where the multi-channel includes a channel to be calibrated and a reference channel, and includes:
a calibration sequence transceiver, configured to obtain a calibration sequence of the channel to be calibrated and a calibration sequence of the reference channel;
the calibration device is connected with the calibration sequence transceiver and is specifically used for:
calculating calibration filter coefficients of the channel to be calibrated by using a frequency domain response between the calibration sequence of the reference channel and the calibration sequence of the channel to be calibrated, wherein the calibration filter coefficients are used for characterizing a calibration filter of the channel to be calibrated;
obtaining a time delay compensation value of the calibration filter by utilizing the calibration filter coefficient;
obtaining a first time delay value of the channel to be calibrated by utilizing the autocorrelation of the calibration sequence of the channel to be calibrated, and obtaining a second time delay value of the reference channel by utilizing the autocorrelation of the calibration sequence of the reference channel;
and obtaining the time delay difference between the channel to be calibrated and the reference channel based on the time delay compensation value of the calibration filter, the first time delay value and the second time delay value, and performing time delay compensation on the channel to be calibrated.
Optionally, the calibration device is specifically configured to:
carrying out frequency domain transformation on the calibration sequence of the channel to be calibrated, and carrying out frequency domain transformation on the calibration sequence of the reference channel;
obtaining a ratio between the frequency domain transformation of the reference channel and the frequency domain transformation of the channel to be calibrated, wherein the ratio is the frequency domain response between the reference channel and the channel to be calibrated;
carrying out Fourier inversion on the frequency domain response to obtain a calibration factor between the reference channel and the channel to be calibrated;
and obtaining the calibration filter coefficient of the channel to be calibrated based on the calibration factor.
Optionally, the calibration device is specifically configured to:
determining M maximum impulse response points corresponding to the calibration factor, wherein the M maximum impulse response points are specifically the calibration filter coefficients, and M is a positive integer;
the obtaining of the delay compensation value of the calibration filter by using the calibration filter coefficient specifically includes:
obtaining M-order tap delay values based on the M maximum impulse response points;
and summing the M-order tap time delay values to obtain a time delay compensation value of the calibration filter.
Optionally, after obtaining the calibration filter coefficients of the channel to be calibrated based on the calibration factor, the calibration apparatus is further configured to:
obtaining a correlation signal;
carrying out convolution multiplication on the correlation signal and the calibration factor to obtain a convolution result;
performing conjugate correlation on the convolution result and the correlation signal;
determining the position information of the highest peak point related to conjugation;
and obtaining a time delay compensation value of the calibration filter based on the position information.
Optionally, the calibration device is specifically configured to:
obtaining a local sequence;
performing conjugate correlation on the calibration sequence of the channel to be calibrated and the local sequence, determining first position information where a highest peak point of the conjugate correlation is located, and performing conjugate correlation on the calibration sequence of the reference channel and the local sequence, and determining second position information where the highest peak point of the conjugate correlation is located;
obtaining the first time delay value of the channel to be calibrated based on the first position information, and obtaining the second time delay value of the reference channel based on the second position information.
Optionally, after obtaining the delay difference between the channel to be calibrated and the reference channel based on the delay compensation value of the calibration filter, the first delay value, and the second delay value, the calibration apparatus is further configured to:
and calibrating the channel to be calibrated based on the time delay difference so that the time delay value of the signal calibrated by the channel to be calibrated is the same as the second time delay value of the reference channel.
In another aspect, an embodiment of the present invention further provides a computer apparatus, including a memory, a processor, and a computer program stored on the memory and executable on the processor, where the processor implements the steps of the method for channel calibration as described above when executing the computer program.
In another aspect, the present invention further provides a computer-readable storage medium, on which a computer program is stored, where the computer program is executed by a processor to implement the steps of the method for channel calibration as described above.
One or more technical solutions in the embodiments of the present invention at least have one or more of the following technical effects:
in the technical scheme of the embodiment of the invention, the calibration sequence of the channel to be calibrated and the calibration sequence of the reference channel are obtained; calculating calibration filter coefficients of the channel to be calibrated by using a frequency domain response between the calibration sequence of the reference channel and the calibration sequence of the channel to be calibrated, wherein the calibration filter coefficients are used for characterizing a calibration filter of the channel to be calibrated; obtaining a time delay compensation value of the calibration filter by using the calibration filter coefficient; obtaining a first time delay value of the channel to be calibrated by utilizing the autocorrelation of the calibration sequence, and obtaining a second time delay value of the reference channel by utilizing the autocorrelation of the calibration sequence of the reference channel; and obtaining the time delay difference between the channel to be calibrated and the reference channel based on the time delay compensation value of the calibration filter, the first time delay value and the second time delay value, and performing time delay compensation on the channel to be calibrated. That is, the frequency domain response of the calibration sequence between the channels is directly utilized to further obtain the calibration filter coefficient of the channel to be calibrated, and further, the time delay compensation value of the calibration filter is obtained; then, the time delay difference between the channel to be calibrated and the reference channel is obtained by utilizing the autocorrelation of the calibration sequence and the time delay compensation value of the calibration filter, so that the time delay of the channel to be calibrated is compensated, the time delay value of the signal calibrated by the channel to be calibrated is further the same as the time delay value of the reference channel, the technical problem of low multi-channel RRU calibration precision in the prior art is effectively solved, and the calibration precision of the multi-channel RRU is improved.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention.
Fig. 1 is a flowchart illustrating steps of a method for calibrating a channel according to an embodiment of the present invention;
fig. 2 is a schematic composition diagram of an eight-channel RRU loop in the method for channel calibration delay compensation according to the first embodiment of the present invention;
fig. 3 is a flowchart illustrating a step S102 in a method for calibrating a channel according to an embodiment of the present invention;
fig. 4 is a flowchart illustrating a step S103 in a method for calibrating a channel according to an embodiment of the present invention;
fig. 5 is a flowchart illustrating steps after step S304 in a method for calibrating a channel according to a first embodiment of the present invention;
fig. 6 is a flowchart illustrating a step S104 in a method for compensating channel calibration delay according to a first embodiment of the present invention;
fig. 7 is a schematic structural diagram of an apparatus for channel calibration according to a second embodiment of the present invention;
fig. 8 is a schematic structural diagram of a device for channel calibration according to a third embodiment of the present invention.
Detailed Description
The embodiment of the invention provides a method and a device for calibrating channels, which are used for solving the technical problem of low calibration precision of multi-channel RRU in the prior art and improving the calibration precision of the multi-channel RRU.
In order to solve the technical problems, the technical scheme in the embodiment of the invention has the following general idea:
a method for calibrating channels is applied to a multi-channel Radio Remote Unit (RRU), wherein the multi-channel RRU comprises a channel to be calibrated and a reference channel, and comprises the following steps:
acquiring a calibration sequence of the channel to be calibrated and a calibration sequence of the reference channel;
calculating calibration filter coefficients of the channel to be calibrated by using a frequency domain response between the calibration sequence of the reference channel and the calibration sequence of the channel to be calibrated, wherein the calibration filter coefficients are used for characterizing a calibration filter of the channel to be calibrated;
obtaining a time delay compensation value of the calibration filter by using the calibration filter coefficient;
obtaining a first time delay value of the channel to be calibrated by utilizing the autocorrelation of the calibration sequence of the channel to be calibrated, and obtaining a second time delay value of the reference channel by utilizing the autocorrelation of the calibration sequence of the reference channel;
and obtaining the time delay difference between the channel to be calibrated and the reference channel based on the time delay compensation value of the calibration filter, the first time delay value and the second time delay value, and performing time delay compensation on the channel to be calibrated.
In the technical scheme of the embodiment of the invention, the calibration sequence of the channel to be calibrated and the calibration sequence of the reference channel are obtained; calculating calibration filter coefficients of the channel to be calibrated by using a frequency domain response between the calibration sequence of the reference channel and the calibration sequence of the channel to be calibrated, wherein the calibration filter coefficients are used for characterizing a calibration filter of the channel to be calibrated; obtaining a time delay compensation value of the calibration filter by using the calibration filter coefficient; obtaining a first time delay value of the channel to be calibrated by utilizing the autocorrelation of the calibration sequence, and obtaining a second time delay value of the reference channel by utilizing the autocorrelation of the calibration sequence of the reference channel; and obtaining the time delay difference between the channel to be calibrated and the reference channel based on the time delay compensation value of the calibration filter, the first time delay value and the second time delay value, and performing time delay compensation on the channel to be calibrated. That is, the frequency domain response of the calibration sequence between the channels is directly utilized to further obtain the calibration filter coefficient of the channel to be calibrated, and further, the time delay compensation value of the calibration filter is obtained; then, the time delay difference between the channel to be calibrated and the reference channel is obtained by utilizing the autocorrelation of the calibration sequence and the time delay compensation value of the calibration filter, so that the time delay of the channel to be calibrated is compensated, the time delay value of the signal calibrated by the channel to be calibrated is further the same as the time delay value of the reference channel, the technical problem of low multi-channel RRU calibration precision in the prior art is effectively solved, and the calibration precision of the multi-channel RRU is improved.
In order to better understand the technical solutions of the present invention, the technical solutions of the present invention are described in detail below with reference to the drawings and the specific embodiments, and it should be understood that the specific features in the embodiments and the embodiments of the present invention are detailed descriptions of the technical solutions of the present invention, and are not limitations of the technical solutions of the present invention, and the technical features in the embodiments and the embodiments of the present invention may be combined with each other without conflict.
Example one
Referring to fig. 1, a method for calibrating a channel according to an embodiment of the present invention is applied to a multi-channel radio remote unit RRU, where the multi-channel includes a channel to be calibrated and a reference channel, and the reference channel is any one channel selected from the multi-channel, and includes:
s101: acquiring a calibration sequence of the channel to be calibrated and a calibration sequence of the reference channel;
s102: calculating calibration filter coefficients of the channel to be calibrated by using a frequency domain response between the calibration sequence of the reference channel and the calibration sequence of the channel to be calibrated, wherein the calibration filter coefficients are used for characterizing a calibration filter of the channel to be calibrated;
s103: obtaining a time delay compensation value of the calibration filter by using the calibration filter coefficient;
s104: obtaining a first time delay value of the channel to be calibrated by utilizing the autocorrelation of the calibration sequence of the channel to be calibrated, and obtaining a second time delay value of the reference channel by utilizing the autocorrelation of the calibration sequence of the reference channel;
s105: and obtaining the time delay difference between the channel to be calibrated and the reference channel based on the time delay compensation value of the calibration filter, the first time delay value and the second time delay value, and performing time delay compensation on the channel to be calibrated.
In the specific implementation process, the specific implementation process of step S101 to step S105 is as follows:
first, step S103 and step S104 have no execution sequence, and those skilled in the art may execute the corresponding steps as needed. Fig. 1 shows only the case where step S104 is executed after step S103 is executed. Specifically, the calibration sequence may be specifically a ZC (Zadoff-Chu) sequence, and may also be a PN sequence, or the like. In a specific implementation process, any one of the PN sequence and the ZC sequence can be used as the calibration sequence by utilizing the characteristics of the PN sequence and the ZC sequence. Taking eight-channel RRU as an example, the length of the calibration sequence is N, and the calibration sequence received by each channel is xi,i∈[1,8]Where the subscript i denotes the ith channel.
And then, calculating the calibration filter coefficient of the channel to be calibrated by using the frequency domain response between the calibration sequence of the reference channel and the calibration sequence of the channel to be calibrated. Specifically, the calibration filter coefficients of the channel to be calibrated are calculated by using the frequency domain response between the calibration sequence of the reference channel and the calibration sequence of the channel to be calibrated, wherein the calibration filter coefficients are used for characterizing the calibration filter of the channel to be calibrated. And then, determining calibration filter coefficients of the channel to be calibrated by using the frequency domain responses between the reference channel and the channel to be calibrated respectively, wherein the calibration filter coefficients are used for representing the calibration filter of the channel to be calibrated. Further, using the calibration filter coefficient, a delay compensation value of the calibration filter is obtained, that is, a delay value generated after the signal passes through the calibration filter is obtained. Further, the time delay values of the channel to be calibrated and the reference channel are respectively obtained by utilizing the autocorrelation of the calibration sequence. Further, the time delay difference between the channel to be calibrated and the reference channel is obtained, and then the channel to be calibrated is subjected to time delay compensation, so that the time delay generated by the calibration filter is compensated, and the calibration precision of the multi-channel RRU is effectively improved.
Referring to fig. 2, a schematic diagram of an eight-channel RRU loop is shown, where RX/TX indicates a radio frequency transceiver end of an RRU, and there are eight radio frequency transceiver ends RX1/TX1, RX2/TX2, RX3/TX3, RX4/TX4, RX5/TX5, RX6/TX6, RX7/TX7, and RX8/TX8, where RX corresponds to a radio frequency receiving end and TX corresponds to a radio frequency transmitting end, there are eight transceiver channels in the eight-channel RRU loop, and each transceiver channel is provided with at least one Power Amplifier module such as a Low Noise Amplifier (LNA) or a Power Amplifier (PA), where the LNA can be used to amplify an uplink signal, and the PA can be used to amplify a downlink signal. And the coupler can transmit the signals transmitted by the multiple channels to the corresponding radio frequency receiving end through the same calibration channel.
In this embodiment of the present invention, a transmission process of the calibration sequence of each channel of the RRU is as follows:
firstly, a radio frequency transmitting end of the RRU in each radio frequency transceiving channel sends a calibration sequence; and then, the calibration sequence passes through a power amplifier module and then reaches the coupler, and the calibration sequence is received by the radio frequency receiving end corresponding to the same calibration channel after passing through the coupler. That is, the calibration sequences respectively passing through the channel to be calibrated and the reference channel are transmitted to the radio frequency receiving end from the same calibration channel after passing through the coupler.
As a specific example, in the downlink of the RRU, the radio frequency transmitting terminals TX1 to TX8 all transmit calibration sequences, and each calibration sequence passes through the same calibration channel via the coupler and is received by the radio frequency receiving terminal RX1 of the same calibration channel. Each calibration sequence may also be received by the rf receiving terminal RX2 through the calibration channel by the coupler, and of course, the calibration sequence may also be received by any one of the rf receiving terminals RX3 to RX8 except the rf receiving terminals RX1 and RX2 by the coupler through the calibration channel, which is not repeated herein. As another example, in the uplink of the RRU, the radio frequency transmitting end TX1 sends a calibration sequence x1The calibration sequence is received by radio frequency receiving ends RX 1-RX 8 after passing through the calibration channel by the coupler. The calibration sequence may also be transmitted by the rf transmitting terminal TX2, and the calibration sequence is received by the rf receiving terminals RX1 to RX8 after passing through the calibration channel via the coupler. Of course, any one of the other TX3 to TX8 except the rf transmitting terminals TX1 and TX2 may also transmit the calibration sequence. Of course, those skilled in the art can select the rf receiving end and the rf transmitting end according to actual needs, which are not illustrated herein.
In addition, for those skilled in the art, the transmission process of other signals besides the calibration sequence may also be controlled according to actual needs, for example, the LTE signal passing through the channel to be calibrated and another LTE signal passing through the reference channel may be transmitted to the radio frequency receiving end from the same calibration channel after passing through the coupler. Of course, other signals may be used, and are not described in detail herein.
In the embodiment of the present invention, please refer to fig. 3, step S102: calculating the calibration filter coefficient of the channel to be calibrated by using the frequency domain response of the calibration sequence between the channels, which specifically comprises the following steps:
s301: carrying out frequency domain transformation on the calibration sequence of the channel to be calibrated, and carrying out frequency domain transformation on the calibration sequence of the reference channel;
s302: obtaining a ratio between the frequency domain transformation of the reference channel and the frequency domain transformation of the channel to be calibrated, wherein the ratio is the frequency domain response between the reference channel and the channel to be calibrated;
s303: carrying out Fourier inversion on the frequency domain response to obtain a calibration factor between the reference channel and the channel to be calibrated;
s304: and obtaining the calibration filter coefficient of the channel to be calibrated based on the calibration factor.
In a specific implementation process, the specific implementation processes of step S301 to step S304 are as follows:
taking an RRU with eight channels as an example, first, frequency domain transformation is performed on the calibration sequences of the channel to be calibrated and the reference channel, respectively. Specifically, the calibration sequence of channel i is subjected to N-point DFT (Discrete Fourier Transform) to obtain a calibration sequence of channel i
Selecting any channel as a reference channel, wherein the frequency domain transformation of the reference channel is represented as XrefThe frequency domain transform of the channel to be calibrated is denoted Xi。
Then, based on the ratio of the frequency domain transformation of the reference channel to the frequency domain transformation of the channel to be calibrated, obtaining the frequency domain response between the reference channel and the channel to be calibrated, namely solving the frequency domain response H between the reference channel and the channel to be calibrated,
for reference channel and to-be-correctedAnd performing Fourier inverse transformation on the frequency domain response H of the quasi-channel i to obtain a calibration factor ht between the reference channel and the channel to be calibratedi
ht (n) A maximum impact response points in the first half of RB sampling points are respectively [ h (0), h (1), … h (A-1)]Tap time delay of [ TA(0),TA(1),...,TA(A-1)](ii) a B maximum impact response points in the second half of BR sampling points are respectively [ h (N-B +1), h (N-B +2) ], h (N)]Where A + B is M and the tap delay is TB(0),TB(1),...,TB(B-1)]. Form [ h (N-B +1), h (N-B +2),. -, h (N), h (0), h (1),. -, h (A-1)]And the filter is the calibration filter coefficient of the filter to be calibrated. The M-order tap coefficients can be selected adaptively according to the system resource condition.
Step S304: obtaining a calibration filter coefficient of the channel to be calibrated based on the calibration factor, specifically comprising: determining M maximum impulse response points corresponding to the calibration factor, where M maximum impulse response points are specifically the calibration filter coefficients, and M is a positive integer, which have been described in detail above and are not described herein again.
In the implementation process, please refer to fig. 4, step S103: obtaining a delay compensation value of the calibration filter by using the calibration filter coefficient, specifically comprising:
s401: obtaining M-order tap delay values based on the M maximum impulse response points;
s402: and summing the M-order tap time delay values to obtain the time delay compensation value of the calibration filter.
In the specific implementation process, the specific implementation process from step S401 to step S402 is as follows:
after the M maximum impulse response points are determined, M-order tap time delay values, specifically T, are obtained
coe=[T
B(0),T
B(1),…T
B(B-1),T
A(0),T
A(1),…T
A(A-1)]. Then, toAnd summing the M-order tap time delay values to obtain the time delay compensation value of the calibration filter. Specifically, the delay compensation value of the calibration filter is:
in the embodiment of the present invention, in addition to the above-mentioned method for obtaining the delay compensation value of the calibration filter based on the sum of tap coefficients, the delay compensation value can be obtained according to a signal correlation method, specifically, referring to fig. 5, in step S304: after obtaining the calibration filter coefficients of the channel to be calibrated based on the calibration factor, the method further includes:
s501: obtaining a correlation signal;
s502: carrying out convolution multiplication on the correlation signal and the calibration factor to obtain a convolution result;
s503: performing conjugate correlation on the convolution result and the correlation signal;
s504: determining the position information of the highest peak point related to conjugation;
s505: obtaining the delay compensation value of the calibration filter based on the position information.
In the specific implementation process, the specific implementation process of steps S501 to S505 is as follows:
to determine how much delay shift the signal will have after passing through the calibration filter, a segment and calibration sequence x is first generatediAnd correlation signals l (N) with the same or different symbol lengths N, wherein l (N) can be the calibration sequence, an LTE signal and the like. In the specific implementation process, the convolution multiplication is carried out on l (n) and h (n) to obtain a convolution result y (n):
y(n)=l(n)*h(n)
conjugate-correlating the convolution result y (n) with the signal l (n):
and (3) obtaining the position information of the relevant high peak point:
(Tfil,value)=max(Rly)
further determining the position information of the highest peak point of conjugate correlation, and obtaining the time delay compensation value T of the calibration filter based on the position informationfil. Of course, it is obvious to those skilled in the art that, besides the above two methods for obtaining the delay compensation value of the calibration filter, other methods may be used to obtain the delay compensation value of the calibration filter according to needs, and the description is not necessarily given here.
In the embodiment of the present invention, please refer to fig. 6, step S104: obtaining a first time delay value of the channel to be calibrated by using the autocorrelation of the calibration sequence of the channel to be calibrated, and obtaining a second time delay value of the reference channel by using the autocorrelation of the calibration sequence of the reference channel, which specifically includes:
s601: obtaining a local sequence;
s602: performing conjugate correlation on the calibration sequence of the channel to be calibrated and the local sequence, determining first position information where a highest peak point of the conjugate correlation is located, and performing conjugate correlation on the calibration sequence of the reference channel and the local sequence, and determining second position information where the highest peak point of the conjugate correlation is located;
s603: respectively determining the position information of the highest peak point related to conjugation;
s604: and obtaining the first time delay value of the channel to be calibrated and the second time delay value of the reference channel.
In the specific implementation process, the specific implementation process of step S601 to step S604 is as follows:
first, a segment and calibration sequence x is generatediAnd (n) local sequences z (n) with the same symbol length are used for time delay calibration. Calibration sequence xi,i∈[1,8]Respectively, performing conjugate correlation with local sequences z (n):
and (3) obtaining the position information of the relevant high peak point:
(Ti,value)=max(Rzx)
and further determining the position information of the highest peak point of conjugate correlation, and obtaining the time delay compensation value of the calibration filter based on the position information. Specifically, TiThat is, the time delay value of the current channel i to be calibrated is determined to be T based on the same implementation processref。
In the embodiment of the present invention, in step S104: after obtaining the first delay value of the channel to be calibrated by using the autocorrelation of the calibration sequence of the channel to be calibrated and obtaining the second delay value of the reference channel by using the autocorrelation of the calibration sequence of the reference channel, the method further includes: and calibrating the channel to be calibrated based on the time delay difference so that the time delay value of the signal calibrated by the channel to be calibrated is the same as the second time delay value of the reference channel. Specifically, after obtaining the delay compensation value of the calibration filter, the first delay value, and the second delay value based on the above two obtaining manners of the delay compensation value of the calibration filter, in a first obtaining manner, a delay difference between the channel to be calibrated and the reference channel is: delay ═reTf-i-TTf(ii) a In a second obtaining manner, a time delay difference between the channel to be calibrated and the reference channel is: delay ═ Tref-Ti-Tfil. And then, calibrating the channel to be calibrated based on the time delay difference, and finally enabling the time delay value of the signal after the signal is calibrated by the channel to be calibrated to be the same as the second time delay value of the reference channel, thereby realizing time delay compensation among multiple channels and effectively improving the precision of time delay calibration among multiple channels.
In the embodiment of the present invention, in step S102: after the calibration filter coefficients of the channel to be calibrated are calculated by using the frequency domain response between the calibration sequence of the reference channel and the calibration sequence of the channel to be calibrated, amplitude and phase compensation can be performed on the channel to be calibrated, and all the channels to be calibrated are calibrated to be the amplitude phase of the same channel (reference channel), that is, the amplitude phase of the channel to be calibrated after calibration tends to be consistent with the amplitude phase of the reference channel. Furthermore, in the embodiment of the invention, the calibration sequence between the channels is used for not only compensating the time delay between the channels, but also compensating the amplitude and phase difference between the channels, thereby improving the precision of the RRU loop.
Example two
Based on the same inventive concept as the first embodiment of the present application, please refer to fig. 7, a second embodiment of the present invention further provides a device for calibrating a channel, which is applied to a multi-channel remote radio unit RRU, where the multi-channel includes a channel to be calibrated and a reference channel, and the device includes:
a calibration sequence transceiver 10, configured to obtain a calibration sequence of the channel to be calibrated and a calibration sequence of the reference channel;
the calibration device 20 is connected to the calibration sequence transceiver 10, and is specifically configured to:
calculating calibration filter coefficients of the channel to be calibrated by using a frequency domain response between the calibration sequence of the reference channel and the calibration sequence of the channel to be calibrated, wherein the calibration filter coefficients are used for characterizing a calibration filter of the channel to be calibrated;
obtaining a time delay compensation value of the calibration filter by using the calibration filter coefficient;
obtaining a first time delay value of the channel to be calibrated and a second time delay value of the reference channel by utilizing the autocorrelation of the calibration sequence;
and obtaining the time delay difference between the channel to be calibrated and the reference channel based on the time delay compensation value of the calibration filter, the first time delay value and the second time delay value, and performing time delay compensation on the channel to be calibrated.
In the embodiment of the present invention, the calibration apparatus 20 is specifically configured to:
carrying out frequency domain transformation on the calibration sequence of the channel to be calibrated, and carrying out frequency domain transformation on the calibration sequence of the reference channel;
obtaining a ratio between the frequency domain transformation of the reference channel and the frequency domain transformation of the channel to be calibrated, wherein the ratio is the frequency domain response between the reference channel and the channel to be calibrated;
carrying out Fourier inversion on the frequency domain response to obtain a calibration factor between the reference channel and the channel to be calibrated;
and obtaining the calibration filter coefficient of the channel to be calibrated based on the calibration factor.
In the embodiment of the present invention, the calibration apparatus 20 is specifically configured to:
determining M maximum impulse response points corresponding to the calibration factor, wherein the M maximum impulse response points are specifically the calibration filter coefficients, and M is a positive integer;
the obtaining of the delay compensation value of the calibration filter by using the calibration filter coefficient specifically includes:
obtaining M-order tap delay values based on the M maximum impulse response points;
and summing the M-order tap time delay values to obtain the time delay compensation value of the calibration filter.
In this embodiment of the present invention, after obtaining the calibration filter coefficients of the channel to be calibrated based on the calibration factor, the calibration apparatus is further configured to:
obtaining a correlation signal;
carrying out convolution multiplication on the correlation signal and the calibration factor to obtain a convolution result;
performing conjugate correlation on the convolution result and the correlation signal;
determining the position information of the highest peak point related to conjugation;
obtaining the delay compensation value of the calibration filter based on the position information.
In the embodiment of the present invention, the calibration apparatus 20 is specifically configured to:
obtaining a local sequence;
performing conjugate correlation on the calibration sequence of the channel to be calibrated and the local sequence, determining first position information where a highest peak point of the conjugate correlation is located, and performing conjugate correlation on the calibration sequence of the reference channel and the local sequence, and determining second position information where the highest peak point of the conjugate correlation is located;
obtaining the first time delay value of the channel to be calibrated based on the first position information, and obtaining the second time delay value of the reference channel based on the second position information.
In this embodiment of the present invention, after obtaining the delay difference between the channel to be calibrated and the reference channel based on the delay compensation value of the calibration filter, the first delay value, and the second delay value, the calibration apparatus 20 is further configured to:
and calibrating the channel to be calibrated based on the time delay difference so that the time delay value of the signal calibrated by the channel to be calibrated is the same as the second time delay value of the reference channel.
EXAMPLE III
Based on the same inventive concept as the embodiment of the present invention, please refer to fig. 8, an embodiment of the present invention further provides a device for calibrating a channel, which is applied to a multi-channel remote radio unit RRU, where the multi-channel includes a channel to be calibrated and a reference channel, and the device includes:
an obtaining unit 30, configured to obtain a calibration sequence of the channel to be calibrated and a calibration sequence of the reference channel;
a calculating unit 40, configured to calculate calibration filter coefficients of the channel to be calibrated by using a frequency domain response between the calibration sequence of the reference channel and the calibration sequence of the channel to be calibrated, where the calibration filter coefficients are used to characterize a calibration filter of the channel to be calibrated;
a first obtaining unit 50, configured to obtain a delay compensation value of the calibration filter by using the calibration filter coefficient;
a second obtaining unit 60, configured to obtain a first delay value of the channel to be calibrated by using the autocorrelation of the calibration sequence of the channel to be calibrated, and obtain a second delay value of the reference channel by using the autocorrelation of the calibration sequence of the reference channel;
a third obtaining unit 70, configured to obtain a delay difference between the channel to be calibrated and the reference channel based on the delay compensation value of the calibration filter, the first delay value, and the second delay value, and perform delay compensation on the channel to be calibrated.
In the embodiment of the present invention, the calculating unit 40 is specifically configured to:
carrying out frequency domain transformation on the calibration sequence of the channel to be calibrated, and carrying out frequency domain transformation on the calibration sequence of the reference channel;
obtaining a ratio between the frequency domain transformation of the reference channel and the frequency domain transformation of the channel to be calibrated, wherein the ratio is the frequency domain response between the reference channel and the channel to be calibrated;
carrying out Fourier inversion on the frequency domain response to obtain a calibration factor between the reference channel and the channel to be calibrated;
and obtaining the calibration filter coefficient of the channel to be calibrated based on the calibration factor.
In the embodiment of the present invention, the calculating unit 40 is specifically configured to:
determining M maximum impulse response points corresponding to the calibration factor, wherein the M maximum impulse response points are specifically the calibration filter coefficients, and M is a positive integer;
the first obtaining unit 50 is specifically configured to:
obtaining M-order tap delay values based on the M maximum impulse response points;
and summing the M-order tap time delay values to obtain the time delay compensation value of the calibration filter.
In an embodiment of the present invention, the apparatus further includes:
a fourth obtaining unit for obtaining a correlation signal;
the first processing unit is specifically configured to:
carrying out convolution multiplication on the correlation signal and the calibration factor to obtain a convolution result;
performing conjugate correlation on the convolution result and the correlation signal;
determining the position information of the highest peak point related to conjugation;
obtaining the delay compensation value of the calibration filter based on the position information.
In the embodiment of the present invention, the second obtaining unit 60 is specifically configured to:
obtaining a local sequence;
performing conjugate correlation on the calibration sequence of the channel to be calibrated and the local sequence, determining first position information where a highest peak point of the conjugate correlation is located, and performing conjugate correlation on the calibration sequence of the reference channel and the local sequence, and determining second position information where the highest peak point of the conjugate correlation is located;
obtaining the first time delay value of the channel to be calibrated based on the first position information, and obtaining the second time delay value of the reference channel based on the second position information.
In this embodiment of the present invention, after obtaining the delay difference between the channel to be calibrated and the reference channel based on the delay compensation value of the calibration filter, the first delay value, and the second delay value, the apparatus further includes:
and the calibration unit calibrates the channel to be calibrated based on the time delay difference so that the time delay value of the signal calibrated by the channel to be calibrated is the same as the second time delay value of the reference channel.
In a further aspect, the present invention provides a computer device, which includes a memory, a processor and a computer program stored in the memory and running on the processor, wherein the processor implements the method according to the above aspects when executing the computer program.
Yet another aspect of the embodiments of the present invention provides a computer-readable storage medium on which a computer program is stored, which, when executed by a processor, implements the method according to the above-described aspects.
One or more technical solutions in the embodiments of the present invention at least have one or more of the following technical effects:
in the technical scheme of the embodiment of the invention, a calibration sequence is obtained; the calibration sequence of the channel to be calibrated and the calibration sequence of the reference channel; calculating calibration filter coefficients of the channel to be calibrated by using a frequency domain response between the calibration sequence of the reference channel and the calibration sequence of the channel to be calibrated, wherein the calibration filter coefficients are used for characterizing a calibration filter of the channel to be calibrated; obtaining a time delay compensation value of the calibration filter by using the calibration filter coefficient; obtaining a first time delay value of the channel to be calibrated by utilizing the autocorrelation of the calibration sequence, and obtaining a second time delay value of the reference channel by utilizing the autocorrelation of the calibration sequence of the reference channel; and obtaining the time delay difference between the channel to be calibrated and the reference channel based on the time delay compensation value of the calibration filter, the first time delay value and the second time delay value, and performing time delay compensation on the channel to be calibrated. That is, the frequency domain response of the calibration sequence between the channels is directly utilized to further obtain the calibration filter coefficient of the channel to be calibrated, and further, the time delay compensation value of the calibration filter is obtained; then, the time delay difference between the channel to be calibrated and the reference channel is obtained by utilizing the autocorrelation of the calibration sequence and the time delay compensation value of the calibration filter, so that the time delay of the channel to be calibrated is compensated, the time delay value of the signal calibrated by the channel to be calibrated is further the same as the time delay value of the reference channel, the technical problem of low multi-channel RRU calibration precision in the prior art is effectively solved, and the calibration precision of the multi-channel RRU is improved.
While preferred embodiments of the present invention 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 such alterations and modifications as fall within the scope of the invention.
It will be apparent to those skilled in the art that various changes and modifications may be made in the present invention without departing from the spirit and scope of the invention. Thus, if such modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include such modifications and variations.