KR20190010153A - Apparatus and Method for Remove of PIMD Using by System Synchronization - Google Patents

Abstract

The present invention relates to an apparatus and method for removing PIMD using system synchronization. A virtual PIMD signal is generated from a downlink (Tx) signal when a PIMD signal is synthesized and input to a real signal at a base station or a relay output terminal. Using the result, a PIMD component included in an uplink (Rx) signal is removed. Since the remaining noise after removing the PIMD synchronizes each part signal to a system clock generated by an oscillator, the PIMD signal is completely removed. The apparatus includes a PIMD signal generating part, a signal processing part, and a system clock synchronizing part.

Description

Technical Field [0001] The present invention relates to a PIMD removal method and apparatus,

The present invention relates to PIMD removal of a repeater, and more particularly, to passive intermodulation distortion (PIMD) generated by signal synthesis in a passive divider or a coaxial cable for antenna branching of a mobile communication base station or an output terminal of a repeater. The present invention relates to an apparatus and a method for removing PIMD using system synchronization.

In recent years, it is evolving into diversification and technology diversity of wireless mobile communication. Accordingly, the development of wireless communication technology has been leading to increase of technical factors such as improvement of wireless environment performance and data processing speed by multi-band service. In various frequency environments in multi - band services, spurious generation or unexpected communication problems are caused by signal synthesis.

Such intermodulation due to various frequency combinations results in communication performance degradation or failure. By eliminating this intermodulation signal, communication problems can be solved.

In addition, the PIMD generated by the multi-band may be generated by combining signals of a third order intermodulation (third order IM) and a fifth order intermodulation (fifth order IM) by synthesis of fundamental, second, and third harmonic signal components Lt; / RTI > The signal PIMD generated by this frequency synthesis is generated in a passive element (divider, connector, etc.), and the generated PIMD signal affects another frequency band, resulting in a communication failure.

Since the generation of the PIMD signal is generated by the combination of the frequency and the signal synthesis, the generation condition of the PIMD signal is listed to generate the signal satisfying the condition and the integrity of the signal can be created. Therefore, it can be removed by performing signal processing such as a PIMD signal generation unit and a cancellation filter unit.

FIG. 1 is a schematic block diagram of a prior art passive device intermodulation signal rejection, which is disclosed in Korean Patent Registration No. 10-1395334.

1, the passive component intermodulation signal removing unit includes a virtual intermodulation signal generating unit 210, an A / D converting unit 220, a second A / D converting unit 230, a correlation filtering unit 240, And a D / A converter 250.

The virtual intermodulation generation unit 210 performs a function of receiving the third transmission signal 30 in which the first transmission signal 10 and the second transmission signal 20 are multiplexed and phase-synchronized from the duplexer 130 .

The virtual intermodulation generation unit 210 generates a virtual intermodulation signal for the third transmission signal 30. In order to generate the virtual intermodulation signal for the third transmission signal 30, the first transmission signal 10 and the second transmission signal 10 corresponding to the first use frequency f1 included in the third transmission signal 30, It is possible to generate a virtual intermodulation signal corresponding to a combined frequency component of sum and difference of harmonic frequencies of the second transmission signal 20 corresponding to the used frequency f2 component.

The correlation filtering unit 240 extracts the correlation between the digital interleaved virtual intermodulation signal and the fourth reception signal 40 and outputs the reverse phase signal of the actual manual intermodulation signal included in the fourth reception signal 40 And performs the function of extracting.

The correlation filtering unit 240 detects a fifth reception signal 50 obtained by removing the actual passive component intermodulation signal included in the fourth reception signal 40 by using the extracted reverse phase signal and outputs the fifth reception signal 50 to the D / (250).

However, such a conventional technique is characterized in that the PIMD signal is removed from the received signal by generating a phase-synchronized virtual intermodulation in which duplex and then RF coaxial coupling is performed. This is because in RF coaxial coupling, The received signal of the uplink path may also be introduced (coupled) to the phase-synchronized virtual inter-modulated signal, so that there may be an error as the virtual modulated signal.

Korean Patent Laid-Open No. 10-2009-0081268 (published on July 28, 2009)

SUMMARY OF THE INVENTION It is an object of the present invention to solve the problems of the prior art by providing a PIMD (Phase Locked Loop) system which combines two transmission signals input from a base station or repeater output, The present invention provides a PIMD elimination apparatus and method that improves the reliability and safety of PIMD signal removal by solving the problems of phase and frequency errors by synchronizing each part signal to a system clock generated by an oscillator.

In order to achieve the above object, a PIMD removal apparatus using system synchronization according to the present invention includes system clock synchronization for eliminating PIMD (Passive Intermodulation Distortion) component generated in a first passive element between a base station or a repeater and an antenna A PIMD removal apparatus comprising: a PIMD signal generation unit for generating a PIMD signal in a downlink signal (TX) received from the base station or a repeater; A signal processor for removing a PIMD signal component from the uplink signal RX transmitted from the antenna using the PIMD signal component generated by the PIMD signal generator and transmitting the PIMD signal component to the base station or the repeater; And a system clock synchronization unit for generating and supplying a system clock to each unit so that each unit of the PIMD removal apparatus operates on the same clock.

Here, the PIMD signal generator includes a second passive element for outputting a downlink signal TX including a PIMD signal to the downlink signal TX; A first filter for passing only a PIMD signal component generated in the second passive element; And a band separator for separating the PIMD signal components having passed through the first filter by each band and outputting the separated PIMD signal components to the signal processing unit.

Wherein the signal processing unit includes: a delay unit for delaying the PIMD signal input from the PIMD signal generation unit; A PIMD cross-correlation calculating unit for calculating a cross-correlation of the PIMD signal input from the delay unit; A virtual PIMD generator for generating a virtual PIMD signal using the PIMD signal input from the delay unit and the PIMD cross-correlation calculation value of the PIMD cross-correlation calculator; And outputting an integrity uplink signal (RX) from which the PIMD signal component generated in the virtual PIMD generator is removed from the uplink signal (RX) including the PIMD component from the antenna side .

The system clock synchronizer generates a clock (fs +?) Shifted by? (Frequency and phase) set on the basis of the sampling clock fs of the DSP to output the first, second ADC, third and fourth ADCs A clock generator for driving the clock generator; A first PLL (Phase Locked Loop) that shifts to the same phase as the clock generated by the clock generator and supplies a clock to the DNC-A and the DNC-B; And a second PLL that shifts to the same phase as the clock generated by the clock generator and supplies a clock to the PIMD DNC-A and the PIMD DNC-B.

In order to achieve the object of the present invention, a method for removing a PIMD using a system clock synchronization includes: outputting an integrity uplink signal (RX) obtained by removing a PIMD (Passive Intermodulation Distortion) component generated between a base station or a repeater and an antenna through a PIMD removing device The method comprising: a first step of synchronizing a clock of each block of the PIMD removal apparatus with a system clock synchronization; A second step of receiving an uplink signal RX including a synchronized real signal and a PIMD signal component through the first process; A third step of outputting an uplink signal RX obtained by removing a virtual PIMD signal component generated by the uplink signal RX; A fourth step of receiving a PIMD signal generated from a downlink signal TX from the base station or a repeater and delaying the PIMD signal at a preset time; And a virtual PIMD signal (Virtual PIMD) through a cross correlation using a delayed PIMD signal through the fourth process and an uplink signal RX from which the PIMD signal component is removed in the third process And a fifth step of providing the virtual PIMD signal generated in the fifth step for removing the PIMD in the third step.

As described above, the method and apparatus for removing PIMD using system clock synchronization according to the present invention can be applied to a PIMD removal method using a PIMD generated by signal synthesis in a passive element or a coaxial cable for antenna branching between a base station or a repeater and an antenna, It is possible to transmit only the real uplink signal RX obtained by removing the PIMD component included in the uplink signal RX by using the virtual PIMD signal.

In addition, a virtual PIMD signal is generated using a PIMD signal generated by combining a downlink signal TX-A (TX-B) of two bands at the end of a base station or a repeater, and a virtual PIMD signal generated through the PIMD signal and a PIMD The PIMD signal is removed through a correlation operation with the uplink signal RX including the signal, thereby effectively removing the PIMD signal.

In addition, the PIMD elimination device for removing the PIMD signal operates synchronously with the clocks shifted by the phase (θ) set on the basis of the DSP sampling frequency, so that the signals are processed in the same motion as the whole, (DNC), it is possible to output the signal without changing the required real signal frequency band. Therefore, if different frequencies and phasers are operated, a residual image is left as it is, It is possible to output the integrity real uplink signal RX-A (RX-B).

1 is a schematic block diagram of a passive device intermodulation signal cancellation according to the prior art,
FIG. 2 is a block diagram of a PIMD removal apparatus using a system clock synchronization according to an embodiment of the present invention.
FIG. 3 is a detailed block diagram of the system clock synchronizing unit in FIG. 2,
FIG. 4 is a detailed block diagram of PIMD removal in FIG. 2,
FIG. 5 is a diagram for explaining a cross-correlation calculation process according to an embodiment of the present invention,
6 is a detailed block diagram of a DSP using a virtual PIMD signal according to an embodiment of the present invention,
FIG. 7 is a view for explaining the adaptive coefficient calculation process according to the embodiment of the present invention,
8 is a flowchart of a PIMD removal process using system synchronization according to an embodiment of the present invention.

The present invention will become more apparent by describing in detail preferred embodiments of the invention with reference to the accompanying drawings

FIG. 2 is a block diagram of a PIMD removal apparatus using system synchronization according to an embodiment of the present invention. Referring to FIG. 2, A PIMD signal removing unit 100 for removing a PIMD signal component includes a PIMD signal generating unit 120 for generating a PIMD signal from a downlink signal TX-A (TX-B) for each band received from the base station or a repeater, (RX-A) (RX-B) transmitted from the antenna (ANT) side using the PIMD signal component generated by the PIMD signal generating unit 120, A signal processor 150 for transmitting the signals to the base station or the repeater and a system clock generator 120 for supplying the system clocks to the units 120 to 150 so that the units 120 to 150 in the PIMD removal apparatus 100 operate on the same clock A system clock synchronization unit 160, a signal processing unit 130 and a first passive element 101, A second MUX / DeMUX unit (not shown) for separating the uplink signals RX input from the first passive element 101 into the bands RX-A and RX-B and inputting the signals to the signal processor 130 Demultiplexes the downlink signal TX input through the base station or the antenna DAS / PPH-RU to a second downlink signal TX-A (TX-B) (DAS / PPH-RU) by multiplexing the uplink signals RX-A and RX-B for each band from which the PIMD signal output from the signal processing unit 130 is removed, (TX-A) TX-B of each band output from the first MUX / DeMUX unit 111 to a PIMD signal generator And couplers (113) and (114) for each band supplied to the respective bands.

Here, the PIMD signal generating unit 120 generates a PIMD signal by outputting a downlink signal TX-A (TX-B) including a PIMD signal to the downlink signal TX-A A first filter 122 for passing only the PIMD signal component generated by the second passive element 121 except for the downlink signal TX-A (TX-B) 1 filter 122, and outputs the separated PIMD signal components to the signal processing unit 130. The band splitting unit 123 separates the PIMD signal components,

The second passive element 121 is a combine that combines the frequencies of the downlink signals TX-A and TX-B for each band. The first passive filter 122, Includes a band rejection filter (BRF) that removes the set band of each frequency of the downlink signal TX-A (TX-B) and passes only the PIMD signal.

5 is a detailed block diagram of a DSP. The DSP 150 includes a delay unit (not shown) for generating a PIMD signal P (n) delayed from a PIMD signal input from the PIMD signal generation unit 120, A PIMD cross-correlation calculating unit 152 (Cross correlation) for calculating a cross-correlation of the PIMD signal P (n) input from the delay unit 151, (N)) using the PIMD cross-correlation calculation value of the PIMD cross-correlation calculation unit 152 and the PIMD signal P (n) input from the PIMD cross- And a virtual PIMD signal from the virtual PIMD generation unit 153 in an uplink signal RX (Z (n)) including the PIMD component from the first passive device 101, And a PIMD removing unit 154 for outputting an integrity uplink signal RX (R (n)) from which the P '(n) component is removed.

3 shows a system clock synchronization unit 160 according to an embodiment of the present invention. The system clock synchronization unit 160 generates a clock signal fs + 1 shifted by a frequency & phase, which is set based on a sampling clock fs of the DSP 150, a clock generator 161 for generating the first and second ADCs 141 and 142 and the third and fourth ADCs 143 and 144 and a clock generator 161 for generating (133) 134, the UPC-A and the UPC-B (135) 136, the clock (Z_LO +?) Shifted by the same phase as the clock (fs + And a clock (PIMD_LO +?) Shifted to the same phase difference (?) As the clock (fs +?) Generated by the clock generator 161 to the PIMD DNC- A 131 and PIMD DNC-B 132 and DAC-A and DAC-B 145 (146).

An embodiment of the present invention will be described in detail with reference to FIGS. 2 to 8. FIG.

First, a PIMD signal generated in a multi-band is divided into a first harmonic signal, a third harmonic signal component, a third harmonic signal component, a third harmonic signal component, a third harmonic signal component, Lt; / RTI > The signal PIMD generated by this frequency synthesis is generated in a passive element (divider, connector, etc.), and the generated signal affects another frequency band, resulting in a communication failure. Since the generation of the PIMD signal is generated by the combination of the frequency and the signal synthesis, the generation condition of the PIMD signal is listed to generate the signal satisfying the condition and the integrity of the signal can be created. Therefore, it can be removed by performing signal processing such as a PIMD signal generation unit and a cancellation filter unit. In addition, the PIMD elimination device is synchronized with each clock signal, so that an integrity signal can be obtained.

That is, the PIMD removing apparatus according to an embodiment of the present invention includes a filter unit (MUX / DeMUX, Duplexer) for each signal flow by connecting between a mobile communication base station and a repeater output terminal (DAS / PPH- (UPC) for converting the signal band RF to IF, an analog / digital conversion unit (ADC), a digital / analog conversion unit (DAC), a DSP , And MCU. Here, the PIMD signal is combined (synthesized) by a divider to generate a PIMD signal in the downlink signals TX-A and TX-B, and the unnecessary portion is filtered to process only the PIMD signal in the DSP. The PIMD signals mixed in the uplink signals RX-A and RX-B are subjected to DSP processing by the cross correlation of the PIMD signals generated in the downlink signals Tx-A and Tx-B, The PIMD elimination device 100 operates in synchronization with clocks of different frequencies and phasors are operated to remove noise that has not been completely removed.

2, a PIMD removal apparatus 100 according to an embodiment of the present invention includes a downlink signal TX received from a base station or a repeater (DAS / PPH-RU) in a first MUX / DeMUX 111 Demultiplexing) and separates and outputs the downlink signal TX-A (TX-B) for each band.

The downlink signal TX-A (TX-B) output through the first MUX / DeMUX 111 is transmitted to the antenna ANT through the second MUX / DeMUX 112.

At this time, the downlink signals TX-A and TX-B are distributed and output through a divider 101, which is a first passive element, at the front end of the plurality of antennas ANT.

As described above, the first passive element 101 or the coaxial cable for transmitting a signal generates PIMD by signal synthesis. In order to remove the PIMD, the first MUX / DeMUX 111 and the second MUX / (TX-A) (TX-B) using the couplings 113 and 114 between the base station 112 and the base station.

The downlink signal TX-A (TX-B) obtained through the couplings 113 and 114 is supplied to the PIMD signal generating unit 120 by the same PIMD signal as that of the first passive device 101 DeMUX 112 using the PIMD signal generated by the PIMD signal generation unit 120 in the signal processing unit 130. The PIMD signal generated by the PIMD signal generation unit 120 is supplied to the RX- A) (RX-B), and outputs the PIMD signal to the first MUX / DeMUX 111.

To this end, the PIMD removal apparatus 100 must operate synchronously with the same system clock.

FIG. 3 is a block diagram illustrating a system clock synchronization according to an embodiment of the present invention. The system clock synchronization unit 160 synchronizes the clocks of the respective parts based on the DSP sampling clock fs.

That is, the frequency and phase characteristics of the PIMD component must be equal to generate the uplink signal RX-A (RX-B) of integrity.

The clock generating unit 161 generates a clock fs +? Shifted by? (Frequency and phase) set on the basis of the sampling clock fs of the DSP 150, The ADCs 141 and 142, and the third and fourth ADCs 143 and 144, respectively.

The first PLL 162 generates a clock Z_LO +? Shifted by the same phase as the clock fs +? Generated by the clock generator 161 and outputs the clock Z_LO +? To the DNC- -B 134 to operate with the supplied clock.

The second PLL 163 generates a clock PIMD_LO +? Shifted by the same phase as the clock fs +? Generated by the clock generator 161 and outputs the clock PIMD_LO +? To the PIMD DNC-A 131 and the PIMD DNC -B 132, the DAC-A 145 and the DAC-B 146 operate with the supplied clock.

The operations of the respective units of the PIMD removing apparatus 100 to be described later operate in synchronization with the clock supplied from the system clock synchronizing unit 160.

The process of calculating the final integrity uplink signals RX-A and RX-B (R) by the PIMD removal apparatus 100 synchronized with the system clock synchronizer 160 is described in the following mathematical expressions Referring to Equation 1 and FIG. 3, the following will be described.

Here, the PIMD signal and the R signal are the real uplink signals RX-A and RX-B, if is an intermediate frequency IF signal, (R + PIMD) in which the real uplink signal RX-A (RX-B) and the PIMD signal are mixed.

Referring to FIG. 3, the signal processing device 120 for PIMD removal, which operates in synchronism with the system clock, will now be described in detail.

The PIMD signal generating unit 120 generates the same PIMD signal as the PIMD signal generated in the first passive device 101 in the second passive device 121. That is, a PIMD signal is generated in the uplink signals RX-A and RX-B using a combiner that combines the respective frequencies of the downlink signals TX-A and TX-B for each band .

The uplink signals RX-A and RX-B in which the PIMD signals are mixed through the second passive elements 121 are input to the first and second filters 122 and 124 through a first filter 122, such as a Band Rejection Filter (BRF) Band signal, while filtering only the PIMD signal component.

The PIMD signal having passed through the first filter 122 is separated into PIMD signals for respective bands through the band separator 123.

The PIMD signal for each band separated through the first filter 122 is converted into an intermediate frequency signal PIMDif through each downconverter (PIMD DNC-A, PIMD DNC-B) 131, 132 And converts the signal into a digital signal PDif by the first and second ADCs 141 and 142 and inputs the digital signal PDif to the DSP 150.

The PIMD signal is generated in the first passive element 101 and the uplink signal RX-A (RX-B) (Z) transmitted through the first passive element 101, A signal Z mixed in the (RX-A) and (RX-B) bands is input to the signal processing unit 120.

That is, the uplink signals RX-A, RX-B, and Z, in which the PIMD signals are mixed, are transmitted through the third and fourth DNCs (DNC-A, DNC- And is converted into a digital signal ZDif through the third and fourth ADCs 143 and 144 and input to the DSP 150. [

The DSP 150 receives the first and second ADCs 141 and 142 from the uplink signals RX-A and RX-B (ZDif) input through the third and fourth ADCs 143 and 144, (-) of the PIMD signals PDif input to the third and fourth ADCs 143 and 144 via the first and second ADCs 142 and 142, The PIMD signal PDif input from the first and second ADCs 141 and 142 is removed from the first and second passive elements RX-B and ZDif, (RX-A) (RX-B) RDif.

The integrity uplink signals RX-A, RX-B and RDif generated by the DSP 150 are supplied to the respective DACs A and B through the first and second DACs DAC-A and DAC- (RX) converted into an RF signal (R) through the corresponding first and second UPCs (UPC-A) and UPC-B -A) (RX-B) to the first MUX / DeMUX 111.

Here, as shown in FIG. 4, the PIMD signal output unit 120 outputs only the PIMD signal PIMD without separating the PIMD signal output from the first filter 122, Converts it into an intermediate frequency signal PIMDif by using one down converter (PIMD DNC) 131a and converts it into a digital signal PDif through the ADC 141a and inputs it to the DSP 150. [

And is input to the DSP 150 which is converted into an intermediate frequency signal Zif and a digital signal ZDif through the down-converter 133a and the ADC 143a. The DSP 150 synthesizes the digital PIMD PDif inputted through the ADC 141a with the digital signal ZDif inputted through the ADC 143a so that the PIMD signal PDif is converted into the real R convert the digital uplink signal Rdif to an analog uplink signal Rif through the DAC-R 145a and output the integrity uplink signal R ) To the first MUX / DeMUX 111.

That is, the DSP 150 generates a virtual PIMD signal from the PIMD signal, removes the PIMD signal from the uplink signal RX-A (RX-B) in which the PIMD is mixed, (RX-A) (RX-B).

FIG. 5 is a detailed block diagram of a cross-correlation calculation for generating a virtual PIMD signal in a DSP. In order to remove a PIMD signal, a DSP must generate the same virtual PIMD signal. The virtual PIMD signal can be calculated through the same cross-correlation with the PIMD signal.

The cross-correlation can be calculated by the following equation (2).

Here, k is the number of samples to be obtained, X (n) is a current input signal, and X (n-k) is a signal in which X (n) is delayed by k.

The cross-correlation value calculated in the calculator calculates a cross-correlation value (CrossCorr_Nor (k)) normalized through a normalization process.

The virtual PIMD value is generated using the thus calculated normalized cross-correlation value (CrossCorr_Nor (k)).

6 is a detailed block diagram of a DSP for removing a PIMD signal of an uplink signal RX-A (RX-B) using a virtual PIMD signal. The input signal is inputted through the first and second ADCs 141 and 142 And outputs the PIMD signal P (n) delayed by a predetermined time through the delay unit 151 to the digital PIMD signal.

The PIMD signal P (n) calculates the cross-correlation value through the cross-correlation calculating unit 152 as shown in Equation (2), and outputs the PIMD signal P (n) supplied through the delay unit 151 And the virtual PIMD signal is generated by receiving the value calculated by the correlation value calculation unit 152 and the correlation value calculation unit 152. That is, the virtual PIMD signal generation is performed by an Adaptive DSP filter, (Adaptive coefficient value).

The following Equation (3) is a method of calculating an adaptive coefficient value (weight value), and the value according to the cross correlation value varies according to the characteristics of the PIMD signal component.

에 의해 연산된 값은 현재의 상호상관관계값이다. 또한, μ값은 상수로서 현재 상호상관관계값이 어느 정도의 상수(배수)로 따라 갈 것인가에 대한 상수이다.6 and 7, the normalized adaptive coefficient value is updated as in Equation (3), where W (n + 1) is the next weight update value, W (n) is the previous weight, P (n) is the known PIMD value (actually occurring PIMD), z (n) is the actual PIMD + R value, Pavg (pz) is the average Power value of p, z, pz is P n) is a multiplication value,

Lt; / RTI > is the current cross-correlation value. Also, the μ value is a constant, which is a constant for what degree of the current cross-correlation value will be followed by a constant (multiple).

FIG. 7 is a detailed block diagram of the cross-correlation calculating unit. The virtual PIMD signal generation using the cross-correlation is implemented by the DSP adaptive filter, which is generated by calculating the adaptive coefficient.

Wherein the adaptive coefficient value is calculated by calculating a cross correlation between a PIMD signal delayed through the delay unit and an actual uplink signal R (n) by using a DSP adaptive filter using an Adaptive Coefficient value, The signal P (n) is multiplied by the cross-correlation coefficient value to generate a virtual PIMD signal P '(n).

The correlation value between the PIMD value P (n) and the actual signal R (n) of the uplink path is calculated by calculating the correlation value of the PIMD (P (n) n) signal by a cross correlation coefficient value to generate a virtual PIMD signal P '(n) in the virtual PIMD generator 153 of the DSP 150.

At this time, the cross correlation coefficient value (μ) has positive and negative values, and the correlation coefficient value (μ) changes adaptively according to the correlation.

The correlation coefficient value μ determines whether the change of the correlation coefficient is fast or slow by a constant and determines the reaction rate of the adaptive filter with respect to the change of the constant value.

7, the Cross Coefficient Operation 152a is a function of a product of the delayed P (n) signal and the actual uplink signal R (n) in the uplink path The mutual coefficient value is calculated by cumulative sum.

The Cross Correlation Value Decision unit 152b can know the operation value of the correlation by a cumulative sum of the signal products due to the cross correlation. Here, it is judged that the cross-correlation value (? W) is high because the cross-correlation is closely correlated with the correlation, and when the correlation value is small, the cross-correlation is far and the correlation is low.

The determination of this determines the threshold value of the correlation and updates the correlation value. The correlation degree determination value is determined by the value calculated by the equation (3) calculated by the DSP 150 or the test.

When the cross correlation value? W is determined, the coefficient driving unit 152c updates the weight value by adding the correlation coefficient to the previous weight value every DSP operation cycle time.

The virtual PIMD generator 153 calculates a product of the updated weight value and the delayed PIMD value P (n) at each DSP operation cycle time. This is applied as a computation coefficient of an adaptive filter to generate a virtual PIMD P '(n).

8 is a flowchart of a PIMD removal process using system synchronization according to an embodiment of the present invention. First, the PIMD signal components mixed in the uplink signals RX-A and RX-B are removed through the PIMD removal device The operation clock for each block in the PIMD removal device is synchronized and then the next step is performed. (S100)

The PIMD generated from the first passive element 101, the connector or the coaxial cable or the like is mixed and input from the antenna ANT to the RX-A (RX-B). (S101)

The downlink signal TX-A received via the base station or the repeater TX-B is received by the PIMD signal generating unit 120 and the uplink signals RX-A and RX- The same PIMD signal as that of the mixed PIMD is generated, delayed for a certain time through the delay unit, and the cross correlation value is calculated. (S110 to S112)

The cross correlation value is calculated using the integrity uplink signal RX-A (RX-B) from which the PIMD signal is removed through the DSP 150 and the PIMD signal.

The cross correlation value calculates an adaptive coefficient value through an adaptive DSP filter (S113)

And generates a virtual PIMD signal using the adaptive coefficient value. (S114)

(RX-A) RX-B (Real Signal) and a PIMD signal by using the generated virtual PIMD signal, and then outputs the integrity uplink signal RX -A) (RX-B) (S102)

As described above, the apparatus and method for removing PIMD using system synchronization according to the present invention have been described with reference to the limited embodiments and drawings, but the present invention is not limited to these embodiments. It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.

100: PIMD removing device 101: first passive element
111, 112: first and second MUX / DeMUXs 113, 114: first and second couplings
120: a PIMD signal generating unit 121: a second passive element
122: first filter 123: band separator
130: Signal processor 131, 132, 133, 134: First to fourth DNC
135, 136: first and second UPCs 141, 142, 143, 144: first to fourth ADCs
145, 146: first and second DAC 150: DSP
151: delay unit 152: cross-correlation calculation unit
153: virtual PIMD generation unit 154: PIMD removal unit
160: system clock synchronization unit 161, 162: first and second PLL

Claims (15)

A PIMD removing apparatus using a system clock synchronization for removing a PIMD (Passive Intermodulation Distortion) component generated in a first passive element between a base station or a repeater and an antenna,
The PIMD removal apparatus includes: a PIMD signal generation unit for generating a PIMD signal from a downlink signal (TX) received from the base station or a repeater;
A signal processor for removing a PIMD signal component from the uplink signal RX transmitted from the antenna using the PIMD signal component generated by the PIMD signal generator and transmitting the PIMD signal component to the base station or the repeater; And
And a system clock synchronization unit for generating and supplying a system clock to each unit of the PIMD removal apparatus so that each unit operates at the same clock. The method according to claim 1,
Wherein the PIMD signal generator comprises: a second passive element for outputting a downlink signal TX including a PIMD signal to the downlink signal;
A first filter for passing only a PIMD signal component generated in the second passive element; And
And a band separator for separating the PIMD signal components having passed through the first filter by a band and outputting the separated PIMD signal components to the signal processing unit. 3. The method of claim 2,
Wherein the second passive element generates the same PIMD signal component as the first passive element on the antenna side. The method of claim 3,
Wherein the second passive element is a combiner that combines respective frequencies of a downlink signal TX-A (TX-B) for each band. 3. The method of claim 2,
Wherein the first filter is a Band Rejection Filter (BRF) that passes only the PIMD signal by removing the set frequency band of each frequency of the downlink signal (TX-A) (TX-B) PIMD removal device using synchronization. The method according to claim 1,
And a second MUX / DeMUX that is added between the signal processing unit and the first passive element and separates the uplink signals RX input from the antenna side into the bands RX-A and RX- part;
A TX-B obtained by demultiplexing a downlink signal TX input through the base station or an antenna by a band to the second MUX / DeMUX unit, and outputs the PIMD signal A first MUX / DeMUX unit for multiplexing the uplink signals (RX-A) and (RX-B) for each band removed from the base station or repeater, And
And each coupler for supplying a downlink signal TX-A (TX-B) of each band output from the first MUX / DeMUX to a PIMD signal generator, . The method according to claim 6,
The signal processing unit includes PIMD DNC-A and PIMD DNC-B for downconverting the PIMD signals for each band generated from the PIMD signal generating unit, first and second ADCs for converting the PIMD signals into digital signals (ADC), respectively;
DNC-A and DNC-B for downconversion of the uplink signals RX-A (RX-B) input from the second MUX / DeMUX, and third and fourth ADCs for digital signal conversion;

A pure uplink signals RX-A, RX-B, and RX-B are obtained by removing the PIMD component from the uplink signals RX-A and RX-B for each band inputted through the first and second ADCs using the PIMD signals input from the first and second ADCs. -A) (RX-B); And
(DAC) for converting (DAC) the pure uplink signals RX-A and RX-B output from the DSP to analog signals, and upconverting them (UPC) respectively to the first MUX / DeMUX Transmitting UPC-A and UPC-B,
Wherein each of the units is driven in synchronization with a clock generated by a system clock synchronization unit. The method according to claim 1,
The signal processing unit uses the PIMD signal input from the PIMD signal generation unit to generate a pure uplink signal RX-A obtained by removing the PIMD signal from the uplink signals RX-A and RX- A) and a digital signal processor (DSP) for outputting only the RX-A (RX-B). 9. The method according to claim 7 or 8,
The DSP includes a delay unit for generating a PIMD signal P (n) by delaying a PIMD signal input from the PIMD signal generation unit.
A PIMD cross-correlation calculating unit for calculating a cross correlation of the PIMD signal P (n) input from the delay unit;
A virtual PIMD generation unit for generating a virtual PIMD signal P '(n) using the PIMD signal P (n) input from the delay unit and the PIMD cross-correlation calculation value of the PIMD cross-correlation calculation unit; And
(R (n)) obtained by removing the PIMD signal (P '(n)) component from the virtual PIMD generator from the uplink signal (RX) including the PIMD component from the antenna side And a PIMD removing unit for removing the PIMD from the system clock. 10. The method of claim 9,
The cross correlation value of the PIMD cross-correlation calculating unit is calculated by a DSP adaptive filter using an adaptive coefficient value,
The adaptive coefficient value is calculated by calculating a cross-correlation between the PIMD signal delayed through the delay unit and the actual uplink signal R (n), multiplying the delayed PIMD signal P (n) by the cross correlation coefficient, And generates a signal P '(n). 10. The method of claim 9,
The PIMD cross-correlation calculating unit calculates a mutual coefficient value by a cumulative sum of the products of the PIMD signal P (n) delayed through the delay unit and the actual uplink signal R (n) (Cross Coefficient Operation);
A cross correlation value decision unit for determining a cross correlation degree based on mutual coefficient values calculated by the mutual coefficient drive unit; And
A coefficient operation unit for adding a correlation value to a previous weight value every DSP operation cycle time and updating a weight value to a high value and a low value in response to a cross-correlation value determined by the cross-correlation value determination unit, The PIMD elimination apparatus using system clock synchronization according to claim 1, 8. The method of claim 1 or 7,
Wherein the system clock synchronizing unit synchronizes the clocks of the respective parts based on the phase (?) Of the sampling clock (fs) of the DSP so that each part of the PIMD removing apparatus has the same phase. 8. The method of claim 7,
The system clock synchronizer generates a clock (fs +?) Shifted by? (Frequency, phase) set on the basis of the sampling clock fs of the DSP and outputs the first, second and third ADCs, A clock generator for driving the clock generator;
A first PLL (Phase Locked Loop) for supplying to the DNC-A and DNC-B a clock (Z_LO +?) Shifted by the same phase as the clock generated by the clock generator; And
And a second PLL for supplying, to the PIMD DNC-A and the PIMD DNC-B, the DAC-A and the DAC-B, a clock (PIMD_LO +?) Shifted by the same phase as the clock generated by the clock generating unit PIMD removal device using system clock synchronization. A PIMD removal method using a system clock synchronization for outputting an integrity uplink signal (RX) obtained by removing a PIMD (Passive Intermodulation Distortion) component generated between a base station or a repeater and an antenna through a PIMD removal device,
A first step of synchronizing a clock for each block of the PIMD removal device;
A second step of receiving an uplink signal RX including a synchronized real signal and a PIMD signal component through the first process;
A third step of outputting an uplink signal RX obtained by removing a virtual PIMD signal component generated by the uplink signal RX;
A fourth step of receiving a PIMD signal generated from a downlink signal TX from the base station or a repeater and delaying the PIMD signal at a preset time;
A virtual PIMD signal (Virtual PIMD) is generated through a cross correlation by using the delayed PIMD signal and the uplink signal RX in which the PIMD signal component is removed in the third process. 5 processes;
Wherein the virtual PIMD signal generated in the fifth step is provided for PIMD removal in the third step. 15. The method of claim 14,
The virtual PIMD signal of the fifth process is calculated by an adaptive DSP filter which calculates an adaptive coefficient value,
Calculating a reciprocal coefficient value by a cumulative sum of the product of the PIMD signal P (n) delayed in the fourth step and the actual uplink signal R (n);
Calculating a cross-correlation value based on the mutual coefficient value, and determining a cross-correlation degree from the cross-correlation value; And
And generating a virtual PIMD signal by updating a weight of the correlation value by adding a correlation coefficient to a previous weight value every DSP operation cycle time as the cross correlation degree is determined. PIMD removal method using synchronization.

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