CN106685868A - Adjacent multiband digital pre-distortion system and method - Google Patents

Adjacent multiband digital pre-distortion system and method Download PDF

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CN106685868A
CN106685868A CN201710001793.2A CN201710001793A CN106685868A CN 106685868 A CN106685868 A CN 106685868A CN 201710001793 A CN201710001793 A CN 201710001793A CN 106685868 A CN106685868 A CN 106685868A
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signal
digital
distortion
power amplifier
nonlinear
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CN106685868B (en
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全欣
刘颖
潘文生
唐友喜
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University of Electronic Science and Technology of China
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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L25/00—Baseband systems
    • H04L25/38—Synchronous or start-stop systems, e.g. for Baudot code
    • H04L25/40—Transmitting circuits; Receiving circuits
    • H04L25/49—Transmitting circuits; Receiving circuits using code conversion at the transmitter; using predistortion; using insertion of idle bits for obtaining a desired frequency spectrum; using three or more amplitude levels ; Baseband coding techniques specific to data transmission systems
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03F—AMPLIFIERS
    • H03F1/00—Details of amplifiers with only discharge tubes, only semiconductor devices or only unspecified devices as amplifying elements
    • H03F1/32—Modifications of amplifiers to reduce non-linear distortion
    • H03F1/3241—Modifications of amplifiers to reduce non-linear distortion using predistortion circuits
    • H03F1/3247—Modifications of amplifiers to reduce non-linear distortion using predistortion circuits using feedback acting on predistortion circuits

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  • Engineering & Computer Science (AREA)
  • Spectroscopy & Molecular Physics (AREA)
  • Computer Networks & Wireless Communication (AREA)
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  • Nonlinear Science (AREA)
  • Power Engineering (AREA)
  • Amplifiers (AREA)

Abstract

The invention discloses an adjacent multiband digital pre-distortion system and method. The system comprises a multiband digital pre-distortion module, a summator, a power amplifier and a multiband pre-distortion parameter calculation module, the multiband digital pre-distortion module comprises multiple digital pre-distorters in parallel running, each digital pre-distorter processes signals from different signal sources at the same time, and an output end of each digital pre-distorter is connected with the summator through a respective radio frequency channel; an output end of the summator is connected with the power amplifier, an output end of the power amplifier is connected with an antenna and further connected with the multiband pre-distortion parameter calculation module through a feedback channel, an output end of the multiband pre-distortion parameter calculation module is connected with each digital pre-distorter, the multiband pre-distortion parameter calculation module calculates to acquire a pre-distortion parameter vector, and then parameters of each digital pre-distorter are adjusted. By the adjacent multiband digital pre-distortion system and method, the digital pre-distorters corresponding to different bands can be adjusted respectively, so that nonlinear distortion of a near-distance multiband power amplifier can be inhibited effectively.

Description

A kind of adjacent multiband digital pre-distortion system and method
Technical field
The present invention relates to a kind of adjacent multiband digital pre-distortion system and method.
Background technology
The generation of multiband power amplifier so that the signal of multiple different frequency ranges can be multiplexed same power amplification Device, so as to cost-effective.However, how pre-distortion is carried out to this multiple signal, it is intrinsic to eliminate power amplifier Non-linear distortion, is an Important Problems.
If carrying out pre-distortion to multiple band signals using the digital pre-distortion method of conventional single band, it needs All band signals are integrated into the signal of a channel, so that the non-constant width of signal bandwidth.Its consequence brought is to need to make With the DAC and ADC of high sampling rate, cost is caused to steeply rise.
The numeral of the non-adjacent multiband of tradition indicates true method, then to each frequency band signals carry out single predistortion respectively Process operation.Because each band separation is larger, the cross modulation effects between its frequency band are ignored.So as to affect adjacent multifrequency Band digital pre-distortion effect.
The content of the invention
It is an object of the invention to overcome the deficiencies in the prior art, there is provided a kind of adjacent multiband digital pre-distortion system with Method, can respectively correct the non-linear distortion of each frequency band of power amplifier.
The purpose of the present invention is achieved through the following technical solutions：A kind of adjacent multiband digital pre-distortion system, Including many band digital pre-distortion blocks, adder, power amplifier and many band pre-distortion parameters computing modules；
Described many band digital pre-distortion blocks include multiple parallel runnings, and correspond numeral with power amplifier different frequency bands Predistorter；Each digital predistorter processes the signal from different signal source simultaneously, and the outfan of digital predistorter leads to Cross respective radio-frequency channel to be connected with adder；The outfan of adder is connected with power amplifier, and the outfan of power amplifier is connected with antenna； The outfan of the power amplifier is also connected by feedback channel with many band pre-distortion parameters computing modules, and band pre-distortion parameters more are calculated The outfan of module is connected respectively with each digital predistorter, and by many band pre-distortion parameters computing modules pre- mistake is calculated True parameter vector, to each digital predistorter parameter adjustment is carried out.
Described radio-frequency channel includes D/A converter module and up-converter module, input and the numeral of D/A converter module Predistorter connects, and the outfan of D/A converter module is connected with up-converter module, the outfan and adder of up-converter module Connection.
Described feedback channel includes down conversion module and analog-to-digital conversion module, and input and the power amplifier of down conversion module connect Connect, the outfan of down conversion module is connected with analog-to-digital conversion module.
Described feedback channel also includes the wave filter being arranged between down conversion module and analog-to-digital conversion module.
Described many band pre-distortion parameters computing modules include：
Many band nonlinear model extraction units, for being led to self feed back is carried out according to the signal of each digital predistorter output The feedback signal in road, extracts many band nonlinear power amplifier models；
Pre-distortion parameters extraction unit, for according to more with nonlinear power amplifier model and each digital predistorter output The pre-distortion parameters vector of signal extraction each digital predistorter.
A kind of adjacent multiband digital pre-distortion method, comprises the following steps：
S1. utilize and process from different signal source simultaneously with each digital predistorter in digital pre-distortion block more Signal u1(n),u2(n),...,uNN (), obtains multiple pre-distorted signals x1(n),x2(n),...,xN(n), the number of signal source It is equal with the number of predistorter, N is, the pre-distorted signals x for obtaining1(n),x2(n),...,xNPower amplifier is contained in (n) The inverse characteristic of nonlinear distortion characteristicses, can reduce or offset the non-linear distortion of power amplifier；
S2. the pre-distorted signals x for each predistorter being obtained1(n),x2(n),...,xNN () is penetrated respectively by respective Synthesize with signal all the way after frequency passageAnd send into after power amplifier is amplified, obtain signalAnd carry out sending out by antenna Penetrate；
S3. the signal of power amplifier output is gatheredDigital signal y (n) is obtained after feedback channel process；
S4. using digital signal y (n) and each road input signal x of power amplifier1(n),x2(n),...,xNN (), carries Pre-distortion parameters vector is taken, each digital predistorter is adjusted.
Described step S1 includes following sub-step：
S11. to the signal u of each signal source1(n),u2(n),...,uNN (), carries out Nonlinear Processing and obtains and each number The corresponding Nonlinear Vector of word predistorter；
S12. it is the pre-distortion parameters of each digital predistorter are vectorial to be multiplied with the transposition of corresponding Nonlinear Vector, obtain To the output signal of each digital predistorter：
The output signal of the 1st predistorter is：
The output signal of the 2nd predistorter is：
……
The output signal of n-th predistorter is：
Wherein, W1For the pre-distortion parameters vector of the 1st predistorter；For the 1st predistorter pair The transposition of the Nonlinear Vector answered；
W2For the pre-distortion parameters vector of the 2nd predistorter；It is corresponding for the 2nd predistorter The transposition of Nonlinear Vector；
WNFor the pre-distortion parameters vector of n-th predistorter；It is corresponding for n-th predistorter The transposition of Nonlinear Vector.
Described step S2 includes following sub-step：
S21. the pre-distorted signals x for each predistorter being obtained1(n),x2(n),...,xNN () is respectively fed to respective Radio-frequency channel；Digital-to-analogue conversion, and up-conversion are carried out to rf frequency；
S22. each pre-distorted signals exported after is processed radio-frequency channel are by adder synthesis with signal all the way
S23. power amplifier is utilized by signalLaunched by antenna after being amplified.
Feedback channel is exported to power amplifier signal in described step S3Carrying out process acquisition digital signal y (n) has Following various ways：
First, willDownconvert to low-frequency range and obtain analogue signal y (t), modulus is directly carried out to analogue signal y (t) and is turned Get digital signal y (n) in return；
Second, to signalEach frequency band distinguishes down coversion, filtering, analog digital conversion, finally changing each frequency band To digital signal synthesis export all the way, obtain digital signal y (n)；
3rd, by signalDown coversion is carried out, in downconversion process, clock signal s is selected by frequency selector1 (t),s2(t),…,sNT in () obtains low frequency signal as conversion frequencies, be filtered and number is obtained after analog digital conversion Word signal y (n).
Described step S4 includes following sub-step：
S41. signal x is utilized1(n),x2(n),...,xNN () and y (n) estimate the nonlinear model of original power amplifier：
(1) the nonlinear power amplifier model of each frequency band is set up：
……
In formula, R1,R2,...,RNThe power amplifier nonlinear parameter of each frequency band is represented, N represents y (n) midband numbers, frequency band And one-to-one corresponding identical with digital predistorter number；y1N () represents the output letter of the nonlinear power amplifier model of the 1st frequency band Number；y2N () represents the output signal of the nonlinear power amplifier model of the 2nd frequency band, yNN () represents the nonlinear power amplifier of n-th frequency band The output signal of model；For the transposition of the 1st corresponding Nonlinear Vector of frequency band； For the transposition of the 2nd corresponding Nonlinear Vector of frequency band；For the corresponding Nonlinear Vector of n-th frequency band Transposition；
(2) due to signal y1(n)、y2(n) and yNN () is all contained in y (n), thus by way of Model Distinguish in from y The nonlinear model shape parameter R of power amplifier is obtained in (n)1,R2,...,RN：
It is by the nonlinear power amplifier model simplification of each frequency band：
Y1=R1Ψ1；
Y2=R2Ψ2；
......
YN=RNΨN；
Y1Represent signal y1The vector of (n) composition；Y2Represent signal y2The vector of (n) composition；YNRepresent signal yNN () constitutes Vector, vector length is A, Ψ1Represent the vectorial Φ N groups continuous time1(x1,x2,...,xN) it is arranged in non-linear square Battle array；Ψ2Represent the vectorial Φ N groups continuous time2(x1,x2,...,xN) it is arranged in non-linear matrix；ΨNRepresent that N groups is continuous The vectorial Ψ of timeN(x1,x2,...,xN) it is arranged in non-linear matrix；
Parametric solution is carried out using LS algorithms, Y is replaced1And Y2For Y；[y (1), y (2) ..., y (N) represent letter to wherein Y= The vector of number y (n) composition；The estimated value for obtaining parameter is：
……
Respectively R1,R2,...,RNEstimated value；
(3) from Non-linear parameter estimation valueRespectively obtain the nonlinear model output of each frequency band Estimated value：
……
S42. signal x is utilized1(n),x2(n),...,xNN estimated value that the nonlinear model of () and each frequency band is exportedExtract pre-distortion parameters：
……
Matrix E1Represent the vectorial Φ N groups continuous time1(y1,y2,...,yN) the non-linear matrix that is arranged in, Φ1 (y1,y2,...,yN) represent to N number of signalCarry out the Nonlinear Vector that Nonlinear Processing is obtained；Square Battle array E2Represent the vectorial Φ N groups continuous time2(y1,y2,...,yN) the non-linear matrix that is arranged in, Φ2(y1,y2,...,yN) Represent to N number of signalCarry out the Nonlinear Vector that Nonlinear Processing is obtained；Matrix ENRepresent N groups The vectorial Φ of continuous timeN(y1,y2,...,yN) the non-linear matrix that is arranged in, ΦN(y1,y2,...,yN) represent to N number of signalCarry out the Nonlinear Vector that Nonlinear Processing is obtained；
Matrix X1,X2,...,XNRespectively：
X1=[x1(1),x1(2),…x1(n)]；
X2=[x2(1),x2(2),…x2(n)]；
……
XN=[xN(1),xN(2),…xN(n)]；
S43. by calculated predistortion vector parameterIt is transferred to the pre- mistake of numeral of correspondence frequency band True device carries out predistortion adjustment to it, replaces original pre-distortion parameters W1,W2..., WN。
The invention has the beneficial effects as follows：The present invention can be from the output signal of power amplifier and many band digital pre-distortion block outputs Signal in, extract the non-linear predistortion parameter comprising non-linear distortion information between frequency band, to different frequency bands correspondence Digital predistorter be adjusted respectively, and then can effectively suppress closely the non-linear of multiband power amplifier to be distortion.
Description of the drawings
Fig. 1 is the system principle diagram of the present invention；
Fig. 2 is method of the present invention flow chart；
Fig. 3 is the schematic diagram of the first signal processing mode of feedback channel；
Fig. 4 is the schematic diagram of second signal processing mode of feedback channel；
Fig. 5 is the schematic diagram of the third signal processing mode of feedback channel.
Specific embodiment
Technical scheme is described in further detail below in conjunction with the accompanying drawings, but protection scope of the present invention is not limited to Described below.
As shown in figure 1, a kind of adjacent multiband digital pre-distortion system, including many band digital pre-distortion blocks, adder, Power amplifier and many band pre-distortion parameters computing modules；
Described many band digital pre-distortion blocks include multiple parallel runnings, and correspond numeral with power amplifier different frequency bands Predistorter (DPD_1~DPD_N)；Each digital predistorter processes the signal from different signal source simultaneously, and numeral is pre- to be lost The outfan of true device is connected by respective radio-frequency channel with adder；The outfan of adder is connected with power amplifier, power amplifier it is defeated Go out end to be connected with antenna；The outfan of the power amplifier is also connected by feedback channel with many band pre-distortion parameters computing modules, many Outfan with pre-distortion parameters computing module is connected respectively with each digital predistorter, is calculated by many band pre-distortion parameters Module is calculated pre-distortion parameters vector, and to each digital predistorter parameter adjustment is carried out.
Described radio-frequency channel includes D/A converter module and up-converter module, input and the numeral of D/A converter module Predistorter connects, and the outfan of D/A converter module is connected with up-converter module, the outfan and adder of up-converter module Connection.
Described feedback channel includes down conversion module and analog-to-digital conversion module, and input and the power amplifier of down conversion module connect Connect, the outfan of down conversion module is connected with analog-to-digital conversion module.
Described feedback channel also includes the wave filter being arranged between down conversion module and analog-to-digital conversion module.
Described many band pre-distortion parameters computing modules include：
Many band nonlinear model extraction units, for being led to self feed back is carried out according to the signal of each digital predistorter output The feedback signal in road, extracts many band nonlinear power amplifier models；
Pre-distortion parameters extraction unit, for according to more with nonlinear power amplifier model and each digital predistorter output The pre-distortion parameters vector of signal extraction each digital predistorter.
As shown in Fig. 2 a kind of adjacent multiband digital pre-distortion method, comprises the following steps：
S1. utilize and process from different signal source simultaneously with each digital predistorter in digital pre-distortion block more Signal u1(n),u2(n),...,uNN (), obtains multiple pre-distorted signals x1(n),x2(n),...,xN(n), the number of signal source It is equal with the number of predistorter, N is, the pre-distorted signals x for obtaining1(n),x2(n),...,xNPower amplifier is contained in (n) The inverse characteristic of nonlinear distortion characteristicses, can reduce or offset the non-linear distortion of power amplifier；
S2. the pre-distorted signals x for each predistorter being obtained1(n),x2(n),...,xNN () is penetrated respectively by respective Synthesize with signal all the way after frequency passageAnd send into after power amplifier is amplified, obtain signalAnd carry out sending out by antenna Penetrate；
S3. the signal of power amplifier output is gatheredDigital signal y (n) is obtained after feedback channel process；
S4. using digital signal y (n) and each road input signal x of power amplifier1(n),x2(n),...,xNN (), carries Pre-distortion parameters vector is taken, each digital predistorter is adjusted.
Described step S1 includes following sub-step：
S11. to the signal u of each signal source1(n),u2(n),...,uNN (), carries out Nonlinear Processing and obtains and each number The corresponding Nonlinear Vector of word predistorter；
S12. it is the pre-distortion parameters of each digital predistorter are vectorial to be multiplied with the transposition of corresponding Nonlinear Vector, obtain To the output signal of each digital predistorter：
The output signal of the 1st predistorter is：
The output signal of the 2nd predistorter is：
……
The output signal of n-th predistorter is：
Wherein, W1For the pre-distortion parameters vector of the 1st predistorter；For the 1st predistorter pair The transposition of the Nonlinear Vector answered；
W2For the pre-distortion parameters vector of the 2nd predistorter；It is corresponding for the 2nd predistorter The transposition of Nonlinear Vector；
WNFor the pre-distortion parameters vector of n-th predistorter；It is corresponding for n-th predistorter The transposition of Nonlinear Vector.
Described step S2 includes following sub-step：
S21. the pre-distorted signals x for each predistorter being obtained1(n),x2(n),...,xNN () is respectively fed to respective Radio-frequency channel；Digital-to-analogue conversion, and up-conversion are carried out to rf frequency；
S22. each pre-distorted signals exported after is processed radio-frequency channel are by adder synthesis with signal all the way
S23. power amplifier is utilized by signalLaunched by antenna after being amplified.
In embodiments herein, feedback channel is exported to power amplifier signal in described step S3Located Reason obtains digital signal y (n) following various ways：
First, as shown in figure 3, willDownconvert to low-frequency range and obtain analogue signal y (t), to analogue signal y (t) directly Carry out analog digital conversion (ADC) and obtain digital signal y (n)；This mode needs that analog digital conversion speed is sufficiently high just to can guarantee that digital letter The all frequency informations of analogue signal y (t) are included in number y (n)；
Second, as shown in figure 4, to signalEach frequency band distinguishes down coversion, filtering, analog digital conversion (ADC), finally handle The digital signal synthesis being converted to of each frequency band are exported all the way, obtain digital signal y (n)；
3rd, as shown in figure 5, by signalDown coversion is carried out, in downconversion process, is selected by frequency selector Clock signal s1(t),s2(t),…,sNT in () obtains low frequency signal as conversion frequencies, be filtered and turn with modulus Change (ADC) and obtain digital signal y (n) afterwards.
Described step S4 includes following sub-step：
S41. signal x is utilized1(n),x2(n),...,xNN () and y (n) estimate the nonlinear model of original power amplifier：
(1) the nonlinear power amplifier model of each frequency band is set up：
……
In formula, R1,R2,...,RNThe power amplifier nonlinear parameter of each frequency band is represented, N represents y (n) midband numbers, frequency band And one-to-one corresponding identical with digital predistorter number；y1N () represents the output letter of the nonlinear power amplifier model of the 1st frequency band Number；y2N () represents the output signal of the nonlinear power amplifier model of the 2nd frequency band, yNN () represents the nonlinear power amplifier of n-th frequency band The output signal of model；For the transposition of the 1st corresponding Nonlinear Vector of frequency band； For the transposition of the 2nd corresponding Nonlinear Vector of frequency band；For the corresponding Nonlinear Vector of n-th frequency band Transposition；
(2) due to signal y1(n)、y2(n) and yNN () is all contained in y (n), thus by way of Model Distinguish in from y The nonlinear model shape parameter R of power amplifier is obtained in (n)1,R2,...,RN：
It is by the nonlinear power amplifier model simplification of each frequency band：
Y1=R1Ψ1；
Y2=R2Ψ2；
......
YN=RNΨN；
Y1Represent signal y1The vector of (n) composition；Y2Represent signal y2The vector of (n) composition；YNRepresent signal yNN () constitutes Vector, vector length is A, Ψ1Represent the vectorial Φ N groups continuous time1(x1,x2,...,xN) it is arranged in non-linear square Battle array；Ψ2Represent the vectorial Φ N groups continuous time2(x1,x2,...,xN) it is arranged in non-linear matrix；ΨNRepresent that N groups is continuous The vectorial Φ of timeN(x1,x2,...,xN) it is arranged in non-linear matrix；
Parametric solution is carried out using LS algorithms, Y is replaced1And Y2For Y；[y (1), y (2) ..., y (N) represent letter to wherein Y= The vector of number y (n) composition；The estimated value for obtaining parameter is：
……
Respectively R1,R2,...,RNEstimated value；
(3) from Non-linear parameter estimation valueRespectively obtain the nonlinear model output of each frequency band Estimated value：
……
S42. signal x is utilized1(n),x2(n),...,xNN estimated value that the nonlinear model of () and each frequency band is exportedExtract pre-distortion parameters：
……
Matrix E1Represent the vectorial Φ N groups continuous time1(y1,y2,...,yN) the non-linear matrix that is arranged in,1(y1, y2,...,yN) represent to N number of signalCarry out the Nonlinear Vector that Nonlinear Processing is obtained；Matrix E2 Represent the vectorial Φ N groups continuous time2(y1,y2,...,yN) the non-linear matrix that is arranged in, Φ2(y1,y2,...,yN) represent To N number of signalCarry out the Nonlinear Vector that Nonlinear Processing is obtained；Matrix ENRepresent that N groups is continuous The vectorial Φ of timeN(y1,y2,...,yN) the non-linear matrix that is arranged in, ΦN(y1,y2,...,yN) represent to N number of signalCarry out the Nonlinear Vector that Nonlinear Processing is obtained；
Matrix X1,X2,...,XNRespectively：
X1=[x1(1),x1(2),…x1(n)]；
X2=[x2(1),x2(2),…x2(n)]；
……
XN=[[xN(1),xN(2),…xN(n)]；
S43. by calculated predistortion vector parameterIt is transferred to corresponding number of bands to lose in advance True device carries out predistortion adjustment to it, replaces original pre-distortion parameters W1,W2..., WN。
In one embodiment of the application, N=2, step S1 is as follows：
Represent to 2 signal sources u1(n),u2(n) carry out that predistortion Nonlinear Processing obtains it is non-linear to Amount, the mid frequency of all elements and signal source u in the vector1N the mid frequency of () is identical, wherein vector A kind of constituted mode of the element of k*j*L+l is：
For pre-distortion parameters vector, vector length withIt is identical；
(i>1, i is odd number) represent to 2 signal sources u1(n),u2N () carries out predistortion Nonlinear Processing and obtains The Nonlinear Vector for arriving, the signal center frequency of all elements and signal source u in the vector1(n),u2The i rank intermodulation components of (n)Mid frequency it is identical, wherein vectorKth * j*L+l element a kind of structure It is into mode：
For pre-distortion parameters vector, vector length withIt is identical；
When all of vectorIt is arranged in order into a vectorAll non-linear Vector is once arranged in a vector
The output of first digit predistorter can be write as：
Wherein T representing matrixs transposition operation.
In the same manner, the output of second digit predistorter can be write as：
Wherein, Φ2(u1,u2) composition and Φ1(u1,u2) similar；Simply constituting concrete vectorWhen, exchange u1(n) and u2The position of (n).
In the embodiment of N=2, step S4 is specific as follows：
The nonlinear power amplifier model for initially setting up 2 frequency bands is as follows：
Wherein, y1(n) and y2N () is respectively first band and the output of second band power amplifier model；Φ1(x1,x2) represent to 2 Individual signal x1(n),x2N () carries out the Nonlinear Vector that Nonlinear Processing is obtained；Its Inner Constitution and Φ1(u1,u2) similar, simply Signal u is replaced respectively1(n),u2N () is x1(n),x2(n)；Φ2(x1,x2) represent to 2 signal x1(n),x2N () carries out non-thread Property process the Nonlinear Vector that obtains；Its Inner Constitution and Φ2(u1,u2) similar, signal u is simply replaced respectively1(n),u2N () is x1(n),x2(n)；
Due to signal y1(n) and y2N () comprising in y (n), can respectively be obtained by way of Model Distinguish from y (n) To nonlinear model the shape parameter R1 and R2 of power amplifier.Concrete discrimination method can be least-squares algorithm (Least Square:LS) Or recursive least squares RLS.By taking LS algorithms as an example：
Above formula is write as matrix form：
Wherein Y1And Y2Signal y is represented respectively1(n) and y2N the vector of () composition, vector length is N；R1 and R2 difference tables Show frequency band 1 and the corresponding nonlinear parameter of frequency band 2 vector, its constituted mode is similar with W1 and W2；Ψ1Represent N group consecutive hourss Between vectorial Φ1(x1,x2) it is arranged in non-linear matrix；Ψ2Represent the vectorial Φ N groups continuous time2(x1,x2) be arranged in it is non- Linear matrix；
Parametric solution is carried out with LS algorithms, and replaces Y1And Y2For Y, the estimated value for obtaining parameter is：
WithThe estimated value of respectively R1 and R2.
From Non-linear parameter estimation valueWithRespectively obtain the estimated value of the nonlinear model output of each frequency band：
Further：
Pre-distortion parameters are extracted：Using x1(n),x2The output of (n) and power amplifier model estimation moduleWithTo extract pre- mistake True parameter, one of which extracting method is as follows：
One of which computational methods can obtain W using traditional indirect learning structure：
Wherein matrix E1Represent the vectorial Φ N groups continuous time1(y1,y2) it is arranged in non-linear matrix；E2Represent N groups The vectorial Φ of continuous time2(y1,y2) it is arranged in non-linear matrix；Φ1(y1,y2) represent to 2 signalsWithCarry out The Nonlinear Vector that Nonlinear Processing is obtained；Its Inner Constitution and Φ1(u1,u2) similar, signal u is simply replaced respectively1(n) and u2 N () isWith 2(y1,y2) represent to 2 signalsWithCarry out that Nonlinear Processing obtains it is non-linear to Amount；Its Inner Constitution and Φ2(u1,u2) similar, signal u is simply replaced respectively1(n) and u2N () isWith
And：
Obtained according to estimationBe transferred to the digital predistorter of correspondence frequency band carries out predistortion adjustment to it, Replace original pre-distortion parameters W1,W2。

Claims (10)

1. a kind of adjacent multiband digital pre-distortion system, it is characterised in that：Including it is many band digital pre-distortion blocks, adder, Power amplifier and many band pre-distortion parameters computing modules；
Described many band digital pre-distortion blocks include multiple parallel runnings, and lose in advance with power amplifier different frequency bands one-to-one corresponding numeral True device；Each digital predistorter processes the signal from different signal source simultaneously, and the outfan of digital predistorter is by each From radio-frequency channel be connected with adder；The outfan of adder is connected with power amplifier, and the outfan of power amplifier is connected with antenna；It is described The outfan of power amplifier is also connected by feedback channel with many band pre-distortion parameters computing modules, more band pre-distortion parameters computing module Outfan be connected with each digital predistorter respectively, by it is many band pre-distortion parameters computing modules be calculated predistortion ginseng Number vector, to each digital predistorter parameter adjustment is carried out.
2. a kind of adjacent multiband digital pre-distortion system according to claim 1, it is characterised in that：Described radio frequency leads to Road includes D/A converter module and up-converter module, and the input of D/A converter module is connected with digital predistorter, and digital-to-analogue turns The outfan of mold changing block is connected with up-converter module, and the outfan of up-converter module is connected with adder.
3. a kind of adjacent multiband digital pre-distortion system according to claim 1, it is characterised in that：Described feedback is led to Road includes down conversion module and analog-to-digital conversion module, and the input of down conversion module is connected with power amplifier, the output of down conversion module End is connected with analog-to-digital conversion module.
4. a kind of adjacent multiband digital pre-distortion system according to claim 1 or 3, it is characterised in that：Described is anti- Feedthrough road also includes the wave filter being arranged between down conversion module and analog-to-digital conversion module.
5. a kind of adjacent multiband digital pre-distortion system according to claim 1, it is characterised in that：Described many bands are pre- Distortion parameter computing module includes：
Many band nonlinear model extraction units, for according to the signal of each digital predistorter output and from feedback channel Feedback signal, extracts many band nonlinear power amplifier models；
Pre-distortion parameters extraction unit, for according to the signal more with nonlinear power amplifier model and each digital predistorter output Extract the pre-distortion parameters vector of each digital predistorter.
6. a kind of adjacent multiband digital pre-distortion method, it is characterised in that：Comprise the following steps：
S1. utilize and process the signal from different signal source simultaneously with each digital predistorter in digital pre-distortion block more u1(n),u2(n),...,uNN (), obtains multiple pre-distorted signals x1(n),x2(n),...,xN(n), the number of signal source and pre- The number of distorter is equal, is N, the pre-distorted signals x for obtaining1(n),x2(n),...,xNThe non-thread of power amplifier is contained in (n) The inverse characteristic of property distorted characteristic, can reduce or offset the non-linear distortion of power amplifier；
S2. the pre-distorted signals x for each predistorter being obtained1(n),x2(n),...,xNN () is logical by respective radio frequency respectively Synthesize with signal all the way behind roadAnd send into after power amplifier is amplified, obtain signalAnd launched by antenna；
S3. the signal of power amplifier output is gatheredDigital signal y (n) is obtained after feedback channel process；
S4. using digital signal y (n) and each road input signal x of power amplifier1(n),x2(n),...,xNN (), extracts pre- Distortion parameter vector, is adjusted to each digital predistorter.
7. a kind of adjacent multiband digital pre-distortion method according to claim 6, it is characterised in that：Described step S1 Including following sub-step：
S11. to the signal u of each signal source1(n),u2(n),...,uNN (), carries out Nonlinear Processing and obtains pre- with each numeral The corresponding Nonlinear Vector of distorter；
S12. it is the pre-distortion parameters of each digital predistorter are vectorial to be multiplied with the transposition of corresponding Nonlinear Vector, obtain each The output signal of individual digital predistorter：
The output signal of the 1st predistorter is：
The output signal of the 2nd predistorter is：
……
The output signal of n-th predistorter is：
Wherein, W1For the pre-distortion parameters vector of the 1st predistorter；It is corresponding for the 1st predistorter The transposition of Nonlinear Vector；
W2For the pre-distortion parameters vector of the 2nd predistorter；For the 2nd corresponding non-thread of predistorter Property vector transposition；
WNFor the pre-distortion parameters vector of n-th predistorter；For the corresponding non-thread of n-th predistorter Property vector transposition.
8. a kind of adjacent multiband digital pre-distortion method according to claim 6, it is characterised in that：Described step S2 Including following sub-step：
S21. the pre-distorted signals x for each predistorter being obtained1(n),x2(n),...,xNN () is respectively fed to respective radio frequency Passage；Digital-to-analogue conversion, and up-conversion are carried out to rf frequency；
S22. each pre-distorted signals exported after is processed radio-frequency channel are by adder synthesis with signal all the way
S23. power amplifier is utilized by signalLaunched by antenna after being amplified.
9. a kind of adjacent multiband digital pre-distortion method according to claim 6, it is characterised in that：Described step S3 In signal that feedback channel is exported to power amplifierCarrying out process acquisition digital signal y (n) has following various ways：
First, willDownconvert to low-frequency range and obtain analogue signal y (t), analog digital conversion is directly carried out to analogue signal y (t) and is obtained To digital signal y (n)；
Second, to signalEach frequency band difference down coversion, filtering, analog digital conversion, finally being converted to each frequency band Digital signal synthesis are exported all the way, obtain digital signal y (n)；
3rd, by signalDown coversion is carried out, in downconversion process, clock signal s is selected by frequency selector1(t),s2 (t),…,sNT in () obtains low frequency signal as conversion frequencies, be filtered and numeral letter is obtained after analog digital conversion Number y (n).
10. a kind of adjacent multiband digital pre-distortion method according to claim 6, it is characterised in that：Described step S4 includes following sub-step：
S41. signal x is utilized1(n),x2(n),...,xNN () and y (n) estimate the nonlinear model of original power amplifier：
(1) the nonlinear power amplifier model of each frequency band is set up：
y 1 ( n ) = R 1 Φ 1 T ( x 1 , x 2 , ... , x N ) ;
y 2 ( n ) = R 2 Φ 2 T ( x 1 , x 2 , ... , x N ) ;
……
y N ( n ) = R N Φ N T ( x 1 , x 2 , ... , x N ) ;
In formula, R1,R2,...,RNThe power amplifier nonlinear parameter of each frequency band is represented, N represents y (n) midband numbers, frequency band and number Word predistorter number is identical and corresponds；y1N () represents the output signal of the nonlinear power amplifier model of the 1st frequency band；y2 N () represents the output signal of the nonlinear power amplifier model of the 2nd frequency band, yNN () represents the nonlinear power amplifier model of n-th frequency band Output signal；For the transposition of the 1st corresponding Nonlinear Vector of frequency band；For the 2nd The transposition of the corresponding Nonlinear Vector of individual frequency band；For the transposition of the corresponding Nonlinear Vector of n-th frequency band；
(2) due to signal y1(n)、y2(n) and yNN () is all contained in y (n), thus by way of Model Distinguish in from y (n) Obtain the nonlinear model shape parameter R of power amplifier1,R2,...,RN：
It is by the nonlinear power amplifier model simplification of each frequency band：
Y1=R1Ψ1；
Y2=R2Ψ2；
......
YN=RNΨN；
Y1Represent signal y1The vector of (n) composition；Y2Represent signal y2The vector of (n) composition；YNRepresent signal yN(n) composition to Amount, vector length is A, Ψ1Represent the vectorial Φ N groups continuous time1(x1,x2,...,xN) it is arranged in non-linear matrix； Ψ2Represent the vectorial Φ N groups continuous time2(x1,x2,...,xN) it is arranged in non-linear matrix；ΨNRepresent N group consecutive hourss Between vectorial ΦN(x1,x2,...,xN) it is arranged in non-linear matrix；
Parametric solution is carried out using LS algorithms, Y is replaced1And Y2For Y；Wherein Y=[y (1), y (2) ..., y (N)], represents signal y The vector of (n) composition；The estimated value for obtaining parameter is：
……
Respectively R1,R2,...,RNEstimated value；
(3) from Non-linear parameter estimation valueRespectively obtain each frequency band nonlinear model output estimate Evaluation：
……
S42. signal x is utilized1(n),x2(n),...,xNN estimated value that the nonlinear model of () and each frequency band is exportedExtract pre-distortion parameters：
W ^ 1 = E 1 H E 1 - 1 E 1 H X 1 ;
W ^ 2 = E 2 H E 2 - 1 E 2 H X 2 ;
……
W ^ N = E N H E N - 1 E N H X N ;
Matrix E1Represent the vectorial Φ N groups continuous time1(y1,y2,...,yN) the non-linear matrix that is arranged in, Φ1(y1, y2,...,yN) represent to N number of signalCarry out the Nonlinear Vector that Nonlinear Processing is obtained；Matrix E2 Represent the vectorial Φ N groups continuous time2(y1,y2,...,yN) the non-linear matrix that is arranged in, Φ2(y1,y2,...,yN) represent To N number of signalCarry out the Nonlinear Vector that Nonlinear Processing is obtained；Matrix ENRepresent that N groups is continuous The vectorial Φ of timeN(y1,y2,...,yN) the non-linear matrix that is arranged in, ΦN(y1,y2,...,yN) represent to N number of signalCarry out the Nonlinear Vector that Nonlinear Processing is obtained；
Matrix X1,X2,...,XNRespectively：
X1=[x1(1),x1(2),…x1(n)]；
X2=[x2(1),x2(2),…x2(n)]；
……
XN=[xN(1),xN(2),…xN(n)]；
S43. by calculated predistortion vector parameterIt is transferred to the digital pre-distortion of corresponding frequency band Device carries out predistortion adjustment to it, replaces original pre-distortion parameters W1,W2..., WN。
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