CN107026673B - Digital-assisted analog domain interference cancellation method and device - Google Patents
Digital-assisted analog domain interference cancellation method and device Download PDFInfo
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- CN107026673B CN107026673B CN201610635672.9A CN201610635672A CN107026673B CN 107026673 B CN107026673 B CN 107026673B CN 201610635672 A CN201610635672 A CN 201610635672A CN 107026673 B CN107026673 B CN 107026673B
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- H04B1/00—Details of transmission systems, not covered by a single one of groups H04B3/00 - H04B13/00; Details of transmission systems not characterised by the medium used for transmission
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- H04B1/52—Hybrid arrangements, i.e. arrangements for transition from single-path two-direction transmission to single-direction transmission on each of two paths or vice versa
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Abstract
The invention discloses a method and a device for canceling digital-assisted analog domain interference, wherein the method comprises four steps of signal transmission, signal feedback, signal reconstruction and signal reception, a nonlinear extraction unit is adopted to estimate nonlinear parameter vectors in the step of signal feedback, and a nonlinear reconstruction unit is adopted to calculate and reconstruct digital transmission signals in the step of signal reconstruction; the device comprises a signal transmitting loop, a signal feedback loop, a signal reconstruction loop and a signal receiving loop. The method can effectively inhibit the nonlinear interference introduced by the transmitting radio frequency channel, can conveniently perform nonlinear estimation and parameter adjustment in a digital domain, can conveniently estimate the multipath channel between the transmitting radio frequency channel and the receiving radio frequency channel in the digital domain, can adjust the parameters, is more beneficial to expanding to other application scenes, and has stronger robustness.
Description
Technical Field
The present invention relates to the field of radio, and in particular, to a method and apparatus for digitally assisted cancellation of interference in the analog domain.
Background
The current wireless communication system adopts a time division duplex or frequency division duplex method to carry out bidirectional communication. The time division duplex system uses the same frequency but different time slots to transmit data, thereby isolating the interference between an uplink and a downlink. Frequency division duplex systems use the same time slot but different frequencies to transmit data, thereby isolating interference between the uplink and downlink. The two duplex methods respectively sacrifice time resources and frequency resources in the process of isolating uplink and downlink, so that the frequency spectrum utilization rate is low.
The demand of the modern society for wireless data service is increasing day by day, and the degree of crowding of the spatial wireless channel is more and more prominent, which compels people to continuously seek new methods to improve the utilization rate of frequency spectrum resources and the anti-interference performance of equipment. If the wireless communication device uses the same time, same frequency full duplex technology to transmit and receive wireless signals, it will undoubtedly double the spectral efficiency of the wireless communication link.
However, simultaneous co-frequency full duplex operates by simultaneously transmitting and receiving rf signals at the same carrier frequency. Therefore, the transmitted signal will also propagate to the receiving end, thereby forming a strong self-interference signal, blocking the receiver analog-to-digital converter, resulting in that the receiver cannot receive the useful signal, the self-interference strength is much stronger than the strength of the signal received by the receiving end from the far-end wireless communication device, thereby seriously affecting the receiving of the signal transmitted by the far-end wireless device by the receiving end. In general, this will reduce the sensitivity of the receiving end, increase the error rate, and cause the communication performance to be reduced; in severe cases, the receiving channel of the receiving end is blocked, which results in complete loss of receiving function and even burning of the front end of the receiver.
Disclosure of Invention
The invention aims to overcome the defects of the prior art and provides a method and a device for canceling digital-assisted analog domain interference, the method can effectively inhibit nonlinear interference introduced by a transmitting radio frequency channel, can conveniently perform nonlinear estimation and parameter adjustment in a digital domain, can conveniently estimate a multipath channel between the transmitting radio frequency channel and a receiving radio frequency channel in the digital domain, adjust parameters, is more beneficial to expanding to other application scenes, and has stronger robustness.
The purpose of the invention is realized by the following technical scheme: a digital-assisted analog domain interference cancellation method comprises four steps of signal transmission, signal feedback, signal reconstruction and signal reception:
the signal transmitting step comprises the following substeps:
s11: the signal to be transmitted is processed by a transmitting baseband unit to obtain a digital signal x [ n ], wherein n represents discrete time:
s12: the digital signal x [ n ] is sent to a first digital-to-analog converter, a nonlinear extraction unit and a nonlinear reconstruction unit respectively;
s13: the digital signal x [ n ] sent to the first digital-to-analog converter is converted into a radio frequency signal x (t) through a transmitting radio frequency channel, wherein t represents continuous time: the radio frequency signals x (t) are respectively sent to the antenna unit and the feedback radio frequency channel;
s14: the radio frequency signal x (t) sent into the antenna unit is transmitted out through the antenna unit;
the signal feedback step comprises the following substeps:
s21: the feedback RF channel receives the RF signal x (t) from the transmitting RF channel, down-converts, filters, and converts the RF signal x (t) to an original digital feedback signal xfb[n]；
S22: raw digital feedback signal xfb[n]The output digital transmission signal x [ n ] sent to the non-linear extraction unit and the transmission baseband unit]Performing time synchronization and power normalization to obtain the sum x [ n ]]Synchronous, equal in power digital feedback signal y [ n ] in time]；
S23: modeling the nonlinear characteristics of the transmit radio frequency channel with a memory polynomial model containing even-order terms, wherein the memory polynomial model containing even-order terms can be expressed as:
where K represents the maximum nonlinear order of the memory polynomial model, Q represents the maximum memory depth of the memory polynomial model, wkqRepresenting the nonlinear parameter of the memory polynomial model at the qth memory depth of the k order;
s24: when two sides of the equation of the formula (1) are simultaneously selected from N groups of data for sorting, the matrix expression of the formula (1) can be obtained: y ═ XW (2)
Wherein Y is [ Y [0 ]]，y[1]，…，y[N-1]]TRepresenting a digital feedback signal y n]N is a column vector consisting of 0,1, …, N-1, and symbol T represents a transposition operation; x represents a digital reflection signal X n]A matrix of dimensions nxkq is composed, which is defined as: x ═ X0，X1，…，XN-1]T
Wherein
W represents a parameter vector composed of nonlinear parameters, defined as:
W＝[W00，…，Wkq，…，W(K-1)(Q-1)]T
s25: solving the equation (2) to calculate the estimation result of the nonlinear parameter vector W
S26: the nonlinear extraction unit extracts the estimation result of the nonlinear parameter vector W
Sending the data into a nonlinear reconstruction unit:
the signal reconstruction step comprises the following substeps:
s31: the nonlinear reconstruction unit receives the digital signal x [ n ] output by the transmitting baseband unit]And the estimation result output by the nonlinear extraction unit, and the signal x [ n ] is subjected to equation (3)]Processing to obtain a reconstructed digital transmission signal xtx[n]Expressed as:
reconstruction of a digital transmission signal xtx[n]Sending the signal into a channel reconstruction unit:
s32: channel reconstruction unit acquiring signal xtx[n]And the output digital received signal r [ n ] of the second analog-to-digital converter]For estimating a multipath channel response h t between a transmitting radio frequency channel and a receiving radio frequency channel](ii) a Multipath channel response h t]Discrete estimation result h [ n ]]Convolution operation is carried out with the reconstructed digital transmitting signal to obtain a digital reconstructed signal xtc[n]As an output signal of the channel reconstruction unit;
s33: digital reconstructed signal xtc[n]Sending the signal to a second digital-to-analog converter for conversion into an analog reconstruction signal xtc(t)；
S34: analog reconstruction signal xtc(t) sending the interference suppression unit;
the signal receiving step comprises the following substeps:
s41: the receiving signal s (t) from the far end enters the interference suppression unit through the antenna unit;
s42: the interference suppression unit receives the receiving signal s (t), and then subtracts the receiving signal s (t) from the radio frequency reconstruction signal z (t) to eliminate the self-interference signal and obtain a low-frequency-band analog receiving signal;
s44: the analog receiving signal is sent to a second analog-to-digital converter to obtain a receiving digital signal sn; the received digital signal s [ n ] is processed by a receiving baseband unit to obtain a desired received signal.
Calculating an estimation result of a non-linear parameter vector W
The method of (1) includes a least squares method and an iterative algorithm.
A digital auxiliary analog domain interference cancellation device comprises a signal transmitting loop, a signal feedback loop, a signal reconstruction loop and a signal receiving loop;
the signal transmitting loop comprises a transmitting baseband unit, a first digital-to-analog converter, a transmitting radio frequency channel and an antenna unit, the transmitting baseband unit processes digital signals of signals to be transmitted and transmits the signals to the first digital-to-analog converter, the nonlinear extraction unit and the nonlinear reconstruction unit, and the digital signals entering the first digital-to-analog converter are converted into radio frequency signals through the transmitting radio frequency channel and transmitted out through the antenna unit;
the signal feedback loop comprises a feedback radio frequency channel, a first analog-to-digital converter and a nonlinear extraction unit, the feedback radio frequency channel receives a radio frequency signal output by a transmitting radio frequency channel, the radio frequency signal is transmitted to the first analog-to-digital converter after down-conversion and filtering and then is converted into a digital feedback signal, the digital feedback signal is transmitted to the nonlinear extraction unit, the nonlinear extraction unit processes the digital feedback signal and a digital signal output by the transmitting baseband unit, and an estimation result of a nonlinear parameter vector W is obtained
And sent to a nonlinear reconstruction unit;
the signal reconstruction loop comprises a nonlinear reconstruction unit, a channel reconstruction unit, a second digital-to-analog converter and a reconstruction radio frequency channel, the nonlinear reconstruction unit receives the digital signal output by the transmitting baseband unit and the estimation result output by the nonlinear extraction unit to calculate and reconstruct a digital transmitting signal and sends the digital transmitting signal to the channel reconstruction unit, the channel reconstruction unit obtains the reconstructed digital transmitting signal and the digital receiving signal output by the second analog-to-digital converter to calculate a digital reconstruction signal and inputs the digital reconstruction signal into the second digital-to-analog converter, and the second digital-to-analog converter converts the digital reconstruction signal into an analog reconstruction signal and transmits the analog reconstruction signal to the interference suppression unit;
the signal receiving loop comprises an antenna unit, an interference suppression unit, a second analog-to-digital converter and a receiving baseband unit, wherein a receiving signal received by the antenna unit is transmitted to the interference suppression unit, the interference suppression unit sends an obtained low-frequency-band analog receiving signal to the second analog-to-digital converter after interference suppression is completed, the second analog-to-digital converter converts the obtained receiving digital signal and transmits the obtained receiving digital signal to the receiving baseband unit, and the receiving baseband unit processes the obtained receiving digital signal to obtain an expected receiving signal.
The antenna unit comprises a circulator and a receiving and transmitting antenna, wherein a radio frequency signal output by a transmitting radio frequency channel is sent to the port 1 of the circulator, then is transmitted to the port 2 of the circulator for output, and is sent to the receiving and transmitting antenna for transmitting: the receiving signal received by the transmitting-receiving antenna enters the port No. 2 of the circulator and then is output to the interference suppression unit from the port No. 3.
The antenna unit comprises a transmitting antenna and a receiving antenna which are independent from each other, and a radio frequency signal output by a transmitting radio frequency channel is transmitted to the transmitting antenna to be transmitted: the reception signal received by the reception antenna is output to the interference suppression unit.
The interference suppression unit comprises a reconstruction radio frequency channel, a radio frequency combiner and a receiving radio frequency channel, the second digital-to-analog converter outputs an analog reconstruction signal to be transmitted to the reconstruction radio frequency channel, the reconstruction radio frequency channel is processed to obtain a radio frequency reconstruction signal and input the radio frequency reconstruction signal into the radio frequency combiner, the receiving signal received by the antenna unit is transmitted to the radio frequency combiner, the radio frequency combiner subtracts the receiving signal from the radio frequency reconstruction signal to eliminate a self-interference signal and outputs the self-interference signal, and the low-frequency-band analog receiving signal is obtained after the receiving radio frequency channel is received and is transmitted to the second analog-to.
The interference suppression unit comprises a combiner and a receiving radio frequency channel, wherein the receiving signals received by the antenna unit are transmitted to the receiving radio frequency channel, the receiving radio frequency channel processes the received signals to obtain low-frequency-band analog receiving signals, the low-frequency-band analog receiving signals are sent to the combiner, and the combiner subtracts the analog receiving signals from analog reconstruction signals output by the second digital-to-analog converter to eliminate self-interference signals and outputs the self-interference signals to the second analog-to-digital converter.
The invention has the beneficial effects that: the invention provides a digital-assisted radio frequency interference cancellation method and a digital-assisted radio frequency interference cancellation device, which can effectively inhibit nonlinear interference introduced by a transmitting radio frequency channel, can conveniently perform nonlinear estimation and parameter adjustment in a digital domain, can conveniently estimate a multipath channel between the transmitting radio frequency channel and a receiving radio frequency channel in the digital domain, adjust parameters, are more beneficial to expanding to other application scenes, and have stronger robustness.
Drawings
FIG. 1 is a block diagram of a digitally assisted analog domain self-interference cancellation apparatus;
FIG. 2 is a first embodiment of a digitally assisted analog domain self-interference cancellation apparatus;
FIG. 3 is a second embodiment of a digitally assisted analog domain self-interference cancellation apparatus;
FIG. 4 is a third embodiment of a digitally assisted analog domain self-interference cancellation apparatus;
fig. 5 is a fourth embodiment of a digitally assisted analog domain self-interference cancellation apparatus.
Detailed Description
The technical solutions of the present invention are further described in detail below with reference to the accompanying drawings, but the scope of the present invention is not limited to the following.
A digital-assisted analog domain interference cancellation method comprises four steps of signal transmission, signal feedback, signal reconstruction and signal reception:
the signal transmitting step comprises the following substeps:
s11: the signal to be transmitted is processed by a transmitting baseband unit to obtain a digital signal x [ n ], wherein n represents discrete time:
s12: the digital signal x [ n ] is sent to a first digital-to-analog converter, a nonlinear extraction unit and a nonlinear reconstruction unit respectively;
s13: the digital signal x [ n ] sent to the first digital-to-analog converter is converted into a radio frequency signal x (t) through a transmitting radio frequency channel, wherein t represents continuous time: the radio frequency signals x (t) are respectively sent to the antenna unit and the feedback radio frequency channel;
s14: the radio frequency signal x (t) sent into the antenna unit is transmitted out through the antenna unit;
the signal feedback step comprises the following substeps:
s21: the feedback RF channel receives the RF signal x (t) from the transmitting RF channel, down-converts, filters, and converts the RF signal x (t) to an original digital feedback signal xfb[n]；
S22: raw digital feedback signal xfb[n]The output digital transmission signal x [ n ] sent to the non-linear extraction unit and the transmission baseband unit]Performing time synchronization and power normalization to obtain the sum x [ n ]]Digital feedback signals y [ n ] that are synchronized in time, equal in power (or very similar)]；
S23: modeling the nonlinear characteristics of the transmit radio frequency channel with a memory polynomial model containing even-order terms, wherein the memory polynomial model containing even-order terms can be expressed as:
where K represents the maximum nonlinear order of the memory polynomial model, Q represents the maximum memory depth of the memory polynomial model, wkqRepresenting the nonlinear parameter of the memory polynomial model at the qth memory depth of the k order;
s24: when two sides of the equation of the formula (1) are simultaneously selected from N groups of data for sorting, the matrix expression of the formula (1) can be obtained: y ═ XW (2)
Wherein Y is [ Y [0 ]]，y[1]，…，y[N-1]]TRepresenting a digital feedback signal y n]N is a column vector consisting of 0,1, …, N-1, and symbol T represents a transposition operation; x represents a digital reflection signal X n]A matrix of dimensions nxkq is composed, which is defined as: x ═ X0，X1，…，XN-1]T
Wherein
W represents a parameter vector composed of nonlinear parameters, defined as:
W＝[W00，…，Wkq，…，W(K-1)(Q-1)]T
s25: solving the equation (2) to calculate the estimation result of the nonlinear parameter vector W
The calculation method comprises a least square method and an iterative algorithm, and the least square solution of the parameter vector W can be obtained by adopting the least square method as follows:
wherein
Calculating the estimation result of the nonlinear parameter vector W by adopting an iterative algorithm
The method comprises the following steps:
where k (n) is a gain vector at the current time, and its expression is:
xi (n) is the prior estimation error at the current moment, and the expression is as follows:
in the formula (6), the reaction mixture is,
T(n)＝P(n-1)Xn(8)
wherein the content of the first and second substances,
lambda is a forgetting factor of the iterative least square RLS algorithm, the value of lambda is a numerical value of 0-1, different values influence the convergence speed of the algorithm, and the lambda is read according to actual needs.
In the initialization phase of the recursive algorithm
And p (0) ═ 1, setting a priori estimation error threshold value in the iterative process of the algorithm to be compared with xi (n), and completing the parameter when the error xi (n) is smaller than the threshold value
And (4) calculating. In this way, the power amplifier fitting model achieves different accuracies;
s26: the nonlinear extraction unit extracts the estimation result of the nonlinear parameter vector WSending the data into a nonlinear reconstruction unit:
the signal reconstruction step comprises the following substeps:
s31: the nonlinear reconstruction unit receives the digital signal output by the transmitting baseband unitNumber x [ n ]]And the estimation result output by the nonlinear extraction unit, and the signal x [ n ] is subjected to equation (3)]Processing to obtain a reconstructed digital transmission signal xtx[n]Expressed as:
reconstruction of a digital transmission signal xtx[n]Sending the signal into a channel reconstruction unit:
s32: channel reconstruction unit acquiring signal xtx[n]And the output digital received signal r [ n ] of the second analog-to-digital converter]For estimating a multipath channel response h t between a transmitting radio frequency channel and a receiving radio frequency channel](ii) a Multipath channel response h t]Discrete estimation result h [ n ]]Convolution operation is carried out with the reconstructed digital transmitting signal to obtain a digital reconstructed signal xtc[n]As an output signal of the channel reconstruction unit;
s33: digital reconstructed signal xtc[n]Sending the signal to a second digital-to-analog converter for conversion into an analog reconstruction signal xtc(t)；
S34: analog reconstruction signal xtc(t) sending the interference suppression unit;
the signal receiving step comprises the following substeps:
s41: the receiving signal s (t) from the far end enters the interference suppression unit through the antenna unit;
s42: the interference suppression unit receives the receiving signal s (t), and then subtracts the receiving signal s (t) from the radio frequency reconstruction signal z (t) to eliminate the self-interference signal and obtain a low-frequency-band analog receiving signal;
s44: the analog receiving signal is sent to a second analog-to-digital converter to obtain a receiving digital signal sn; the received digital signal s [ n ] is processed by a receiving baseband unit to obtain a desired received signal.
When the antenna unit is a circulator and a receiving and transmitting antenna, the radio frequency signal s (t) is sent into the port I of the circulator, then is transmitted to the port 2 of the circulator for output, and is sent to the receiving and transmitting antenna for transmission: the received signal r (t) from the far end enters the port No. 2 of the circulator through the transceiving antenna and then is output to the interference suppression unit from the port No. 3.Due to the limited isolation of the circulator, the radio frequency signal s (t) leaks to the No. 3 port and enters the receiving radio frequency channel to form a self-interference signal. At this time, the second digital-to-analog converter outputs an analog reconstruction signal xtc(t) sending the radio frequency reconstruction channel to obtain a radio frequency reconstruction signal z (t), sending the radio frequency reconstruction signal z (t) into a radio frequency combiner, subtracting the radio frequency reconstruction signal z (t) after the radio frequency combiner receives the receiving signal r (t) to eliminate a self-interference signal, and sending the output of the radio frequency combiner to a second analog-to-digital conversion module after the radio frequency combiner receives the radio frequency channel to obtain a low-frequency-band analog receiving signal.
When the output signal power of the antenna unit is within the bearing range of the power sensitive device in the receiving radio frequency channel and the receiving radio frequency channel can not introduce interference (such as nonlinear distortion of a low noise amplifier) to the signal additionally, the interference suppression unit only comprises a combiner and the receiving radio frequency channel, the receiving signal received by the antenna unit is transmitted to the receiving radio frequency channel, the receiving radio frequency channel is processed to obtain a low-frequency-band analog receiving signal, the low-frequency-band analog receiving signal is sent to the combiner, and the combiner subtracts the analog receiving signal from the analog reconstruction signal output by the second digital-to-analog converter to eliminate the self-interference signal and outputs the self-interference signal to the second analog-to-digital converter.
As shown in fig. 1, a digitally-assisted analog domain interference cancellation apparatus includes a signal transmitting loop, a signal feedback loop, a signal reconstruction loop, and a signal receiving loop;
the signal transmitting loop comprises a transmitting baseband unit, a first digital-to-analog converter, a transmitting radio frequency channel and an antenna unit, the transmitting baseband unit processes digital signals of signals to be transmitted and transmits the signals to the first digital-to-analog converter, the nonlinear extraction unit and the nonlinear reconstruction unit, and the digital signals entering the first digital-to-analog converter are converted into radio frequency signals through the transmitting radio frequency channel and transmitted out through the antenna unit;
the signal feedback loop comprises a feedback radio frequency channel, a first analog-to-digital converter and a nonlinear extraction unit, the feedback radio frequency channel receives a radio frequency signal output by a transmitting radio frequency channel, the radio frequency signal is transmitted to the first analog-to-digital converter after down-conversion and filtering and is converted into a digital feedback signal, the digital feedback signal is transmitted to the nonlinear extraction unit, and the nonlinear extraction unitProcessing the digital feedback signal and the digital signal output by the transmitting baseband unit to obtain the estimation result of the nonlinear parameter vector W
And sent to a nonlinear reconstruction unit;
the signal reconstruction loop comprises a nonlinear reconstruction unit, a channel reconstruction unit, a second digital-to-analog converter and a reconstruction radio frequency channel, the nonlinear reconstruction unit receives the digital signal output by the transmitting baseband unit and the estimation result output by the nonlinear extraction unit to calculate and reconstruct a digital transmitting signal and sends the digital transmitting signal to the channel reconstruction unit, the channel reconstruction unit obtains the reconstructed digital transmitting signal and the digital receiving signal output by the second analog-to-digital converter to calculate a digital reconstruction signal and inputs the digital reconstruction signal into the second digital-to-analog converter, and the second digital-to-analog converter converts the digital reconstruction signal into an analog reconstruction signal and transmits the analog reconstruction signal to the interference suppression unit;
the signal receiving loop comprises an antenna unit, an interference suppression unit, a second analog-to-digital converter and a receiving baseband unit, wherein a receiving signal received by the antenna unit is transmitted to the interference suppression unit, the interference suppression unit sends an obtained low-frequency-band analog receiving signal to the second analog-to-digital converter after interference suppression is completed, the second analog-to-digital converter converts the obtained receiving digital signal and transmits the obtained receiving digital signal to the receiving baseband unit, and the receiving baseband unit processes the obtained receiving digital signal to obtain an expected receiving signal.
As shown in fig. 2, in an embodiment of the present invention, the antenna unit includes a circulator and a transceiver antenna, and the rf signal output by the transmitting rf channel is sent to port No. 1 of the circulator, then is sent to port No. 2 of the circulator for output, and is sent to the transceiver antenna for transmission: the receiving signal received by the transmitting-receiving antenna enters the port No. 2 of the circulator and then is output to the interference suppression unit from the port No. 3.
As shown in fig. 3, in another embodiment of the present invention, the antenna unit includes a transmitting antenna and a receiving antenna that are independent from each other, and the rf signal output by the transmitting rf channel is transmitted to the transmitting antenna for transmission: the reception signal received by the reception antenna is output to the interference suppression unit.
As shown in fig. 4, in the third embodiment of the present invention, the interference suppression unit includes a reconstructed radio frequency channel, a radio frequency combiner, and a received radio frequency channel, the second digital-to-analog converter outputs an analog reconstructed signal to the reconstructed radio frequency channel, the reconstructed radio frequency channel is processed to obtain a radio frequency reconstructed signal and inputs the radio frequency reconstructed signal to the radio frequency combiner, the received signal received by the antenna unit is transmitted to the radio frequency combiner, the radio frequency combiner subtracts the received signal from the radio frequency reconstructed signal to eliminate a self-interference signal and outputs the self-interference signal, and the received radio frequency channel obtains a low-frequency-band analog received signal and sends the low-frequency-band analog received signal to the.
As shown in fig. 5, in the fourth embodiment of the present invention, the interference suppression unit includes a combiner and a receiving radio frequency channel, the receiving signal received by the antenna unit is transmitted to the receiving radio frequency channel, the receiving radio frequency channel processes the received signal to obtain a low-frequency analog receiving signal, and the low-frequency analog receiving signal is transmitted to the combiner, and the combiner subtracts the analog receiving signal from the analog reconstruction signal output by the second digital-to-analog converter to eliminate the self-interference signal, and outputs the self-interference signal to the second analog-to-digital converter.
Claims (7)
1. A digital-assisted analog domain interference cancellation method is characterized in that: the method comprises four steps of signal transmission, signal feedback, signal reconstruction and signal reception:
the signal transmitting step comprises the following substeps:
s11: the signal to be transmitted is processed by a transmitting baseband unit to obtain a digital signal x [ n ], wherein n represents discrete time:
s12: the digital signal x [ n ] is sent to a first digital-to-analog converter, a nonlinear extraction unit and a nonlinear reconstruction unit respectively;
s13: the digital signal x [ n ] sent to the first digital-to-analog converter is converted into a radio frequency signal x (t) through a transmitting radio frequency channel, wherein t represents continuous time: the radio frequency signals x (t) are respectively sent to the antenna unit and the feedback radio frequency channel;
s14: the radio frequency signal x (t) sent into the antenna unit is transmitted out through the antenna unit;
the signal feedback step comprises the following substeps:
s21: the feedback RF channel receives the RF signal x (t) from the transmitting RF channel, down-converts, filters, and converts the RF signal x (t) to an original digital feedback signal xfb[n]；
S22: raw digital feedback signal xfb[n]The output digital transmission signal x [ n ] sent to the non-linear extraction unit and the transmission baseband unit]Performing time synchronization and power normalization to obtain the sum x [ n ]]Synchronous, equal in power digital feedback signal y [ n ] in time]；
S23: modeling the nonlinear characteristics of the transmit radio frequency channel with a memory polynomial model containing even-order terms, wherein the memory polynomial model containing even-order terms can be expressed as:
where K represents the maximum nonlinear order of the memory polynomial model, Q represents the maximum memory depth of the memory polynomial model, wkqRepresenting the nonlinear parameter of the memory polynomial model at the qth memory depth of the k order;
s24: when two sides of the equation of the formula (1) are simultaneously selected from N groups of data for sorting, the matrix expression of the formula (1) can be obtained: y ═ XW (2)
Wherein Y is [ Y [0 ]]，y[1]，…，y[N-1]]TRepresenting a digital feedback signal y n]N is a column vector consisting of 0,1, …, N-1, and symbol T represents a transposition operation; x represents a digital reflection signal X n]A matrix of dimensions nxkq is composed, which is defined as: x ═ X0，X1，…，XN-1]T
Wherein
W represents a parameter vector composed of nonlinear parameters, defined as:
W＝[W00，…，Wkq，…，W(K-1)(Q-1)]T
s25: solving the equation (2) to calculate the estimation result of the nonlinear parameter vector W
S26: the nonlinear extraction unit extracts the estimation result of the nonlinear parameter vector W
Sending the data into a nonlinear reconstruction unit:
the signal reconstruction step comprises the following substeps:
s31: the nonlinear reconstruction unit receives the digital signal x [ n ] output by the transmitting baseband unit]And the estimation result output by the nonlinear extraction unit, and the signal x [ n ] is subjected to equation (3)]Processing to obtain a reconstructed digital transmission signal xtx[n]Expressed as:
reconstruction of a digital transmission signal xtx[n]Sending the signal into a channel reconstruction unit:
s32: channel reconstruction unit acquiring signal xtx[n]And the output digital received signal r [ n ] of the second analog-to-digital converter]For estimating a multipath channel response h t between a transmitting radio frequency channel and a receiving radio frequency channel](ii) a Multipath channel response h t]Discrete estimation result h [ n ]]Convolution operation is carried out with the reconstructed digital transmitting signal to obtain a digital reconstructed signal xtc[n]As an output signal of the channel reconstruction unit;
s33: digital reconstructed signal xtc[n]Sending the signal to a second digital-to-analog converter for conversion into an analog reconstruction signal xtc(t)；
S34: analog reconstruction signal xtc(t) sending the interference suppression unit;
the signal receiving step comprises the following substeps:
s41: the receiving signal s (t) from the far end enters the interference suppression unit through the antenna unit;
s42: the interference suppression unit receives the receiving signal s (t), and then subtracts the receiving signal s (t) from the radio frequency reconstruction signal z (t) to eliminate the self-interference signal and obtain a low-frequency-band analog receiving signal;
s44: the analog receiving signal is sent to a second analog-to-digital converter to obtain a receiving digital signal sn; the received digital signal s [ n ] is processed by a receiving baseband unit to obtain a desired received signal.
2. The method of claim 1, wherein the method further comprises: calculating an estimation result of a non-linear parameter vector W
The method of (1) includes a least squares method and an iterative algorithm.
3. A digitally-assisted analog domain interference cancellation arrangement applying the analog domain interference cancellation method according to any one of claims 1-2, characterized by: the system comprises a signal transmitting loop, a signal feedback loop, a signal reconstruction loop and a signal receiving loop;
the signal transmitting loop comprises a transmitting baseband unit, a first digital-to-analog converter, a transmitting radio frequency channel and an antenna unit, the transmitting baseband unit processes digital signals of signals to be transmitted and transmits the signals to the first digital-to-analog converter, the nonlinear extraction unit and the nonlinear reconstruction unit, and the digital signals entering the first digital-to-analog converter are converted into radio frequency signals through the transmitting radio frequency channel and transmitted out through the antenna unit;
the signal feedback loop comprises a feedback radio frequency channel, a first analog-to-digital converter and a nonlinear extraction unit, the feedback radio frequency channel receives a radio frequency signal output by the transmitting radio frequency channel, the radio frequency signal is transmitted to the first analog-to-digital converter after down-conversion and filtering, the radio frequency signal is converted into a digital feedback signal and transmitted to the nonlinear extraction unit, and the nonlinear extraction unit carries out digital feedback signal and digital signal output by the transmitting baseband unitProcessing to obtain the estimation result of the nonlinear parameter vector WAnd sent to a nonlinear reconstruction unit;
the signal reconstruction loop comprises a nonlinear reconstruction unit, a channel reconstruction unit, a second digital-to-analog converter and a reconstruction radio frequency channel, the nonlinear reconstruction unit receives the digital signal output by the transmitting baseband unit and the estimation result output by the nonlinear extraction unit to calculate and reconstruct a digital transmitting signal and sends the digital transmitting signal to the channel reconstruction unit, the channel reconstruction unit obtains the reconstructed digital transmitting signal and the digital receiving signal output by the second analog-to-digital converter to calculate a digital reconstruction signal and inputs the digital reconstruction signal into the second digital-to-analog converter, and the second digital-to-analog converter converts the digital reconstruction signal into an analog reconstruction signal and transmits the analog reconstruction signal to the interference suppression unit;
the signal receiving loop comprises an antenna unit, an interference suppression unit, a second analog-to-digital converter and a receiving baseband unit, wherein a receiving signal received by the antenna unit is transmitted to the interference suppression unit, the interference suppression unit sends an obtained low-frequency-band analog receiving signal to the second analog-to-digital converter after interference suppression is completed, the second analog-to-digital converter converts the obtained receiving digital signal and transmits the obtained receiving digital signal to the receiving baseband unit, and the receiving baseband unit processes the obtained receiving digital signal to obtain an expected receiving signal.
4. A digitally-assisted analog domain interference cancellation arrangement according to claim 3, wherein: the antenna unit comprises a circulator and a receiving and transmitting antenna, wherein a radio frequency signal output by a transmitting radio frequency channel is sent to the port 1 of the circulator, then is transmitted to the port 2 of the circulator for output, and is sent to the receiving and transmitting antenna for transmitting: the receiving signal received by the transmitting-receiving antenna enters the port No. 2 of the circulator and then is output to the interference suppression unit from the port No. 3.
5. A digitally-assisted analog domain interference cancellation arrangement according to claim 3, wherein: the antenna unit comprises a transmitting antenna and a receiving antenna which are independent from each other, and a radio frequency signal output by a transmitting radio frequency channel is transmitted to the transmitting antenna to be transmitted: the reception signal received by the reception antenna is output to the interference suppression unit.
6. A digitally-assisted analog domain interference cancellation arrangement according to claim 3, wherein: the interference suppression unit comprises a reconstruction radio frequency channel, a radio frequency combiner and a receiving radio frequency channel, the second digital-to-analog converter outputs an analog reconstruction signal to be transmitted to the reconstruction radio frequency channel, the reconstruction radio frequency channel is processed to obtain a radio frequency reconstruction signal and input the radio frequency reconstruction signal into the radio frequency combiner, the receiving signal received by the antenna unit is transmitted to the radio frequency combiner, the radio frequency combiner subtracts the receiving signal from the radio frequency reconstruction signal to eliminate a self-interference signal and outputs the self-interference signal, and the low-frequency-band analog receiving signal is obtained after the receiving radio frequency channel is received and is transmitted to the second analog-to.
7. A digitally-assisted analog domain interference cancellation arrangement according to claim 3, wherein: the interference suppression unit comprises a combiner and a receiving radio frequency channel, wherein the receiving signals received by the antenna unit are transmitted to the receiving radio frequency channel, the receiving radio frequency channel processes the received signals to obtain low-frequency-band analog receiving signals, the low-frequency-band analog receiving signals are sent to the combiner, and the combiner subtracts the analog receiving signals from analog reconstruction signals output by the second digital-to-analog converter to eliminate self-interference signals and outputs the self-interference signals to the second analog-to-digital converter.
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| CN110611521B (en) * | 2018-06-15 | 2022-04-15 | 中兴通讯股份有限公司 | Full-duplex self-interference cancellation method, equipment and computer-readable storage medium |
| CN109274388B (en) * | 2018-09-30 | 2021-06-04 | 中国人民解放军海军工程大学 | Radio frequency cancellation device and method for digital domain interference reconstruction |
| CN113114286B (en) * | 2021-04-14 | 2022-04-29 | 中国人民解放军陆军工程大学 | Low-complexity radio frequency front-end adjacent channel interference suppression device |
| CN113922867B (en) * | 2021-12-13 | 2022-02-22 | 中国人民解放军海军工程大学 | Non-cooperative interference cancellation device and method for partial frequency band protection |
| CN115001913B (en) * | 2022-08-02 | 2022-11-29 | 北京理工大学 | Full-duplex frequency domain self-interference elimination method based on digital assistance |
| CN116054853A (en) * | 2023-01-13 | 2023-05-02 | 电子科技大学 | Robust phased array self-interference digital domain suppression method |
| CN115955258B (en) * | 2023-03-13 | 2023-05-30 | 中国人民解放军国防科技大学 | Navigation signal receiving and transmitting isolation self-adaptive cancellation method based on reference waveform |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103338172A (en) * | 2013-07-24 | 2013-10-02 | 电子科技大学 | Simultaneous common-frequency full duplex self-interference offset method in multi-path environment |
| CN104779971A (en) * | 2014-11-07 | 2015-07-15 | 哈尔滨工业大学深圳研究生院 | Non-linear digital self-interference cancellation method combined with simulation cancellation algorithm |
| CN104935540A (en) * | 2015-05-21 | 2015-09-23 | 电子科技大学 | Same-time and same-frequency full-duplex limit self-interference offset method |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US9712312B2 (en) * | 2014-03-26 | 2017-07-18 | Kumu Networks, Inc. | Systems and methods for near band interference cancellation |
-
2016
- 2016-08-04 CN CN201610635672.9A patent/CN107026673B/en active Active
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103338172A (en) * | 2013-07-24 | 2013-10-02 | 电子科技大学 | Simultaneous common-frequency full duplex self-interference offset method in multi-path environment |
| CN104779971A (en) * | 2014-11-07 | 2015-07-15 | 哈尔滨工业大学深圳研究生院 | Non-linear digital self-interference cancellation method combined with simulation cancellation algorithm |
| CN104935540A (en) * | 2015-05-21 | 2015-09-23 | 电子科技大学 | Same-time and same-frequency full-duplex limit self-interference offset method |
Non-Patent Citations (1)
| Title |
|---|
| 《Full Duplex Radios-Stanford University》;start2015a38;《豆丁》;20151205;正文第1-12页 * |
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