CN117040450A - Piecewise linear digital predistortion system and method for temperature compensation of power amplifier - Google Patents
Piecewise linear digital predistortion system and method for temperature compensation of power amplifier Download PDFInfo
- Publication number
- CN117040450A CN117040450A CN202310871150.9A CN202310871150A CN117040450A CN 117040450 A CN117040450 A CN 117040450A CN 202310871150 A CN202310871150 A CN 202310871150A CN 117040450 A CN117040450 A CN 117040450A
- Authority
- CN
- China
- Prior art keywords
- temperature
- power amplifier
- digital predistortion
- radio frequency
- parameters
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
- 238000000034 method Methods 0.000 title claims abstract description 62
- 230000001419 dependent effect Effects 0.000 claims description 5
- 238000012545 processing Methods 0.000 claims description 4
- 238000005070 sampling Methods 0.000 claims description 4
- 230000011218 segmentation Effects 0.000 claims description 4
- 230000008569 process Effects 0.000 claims description 3
- 230000009471 action Effects 0.000 claims description 2
- 230000003321 amplification Effects 0.000 claims description 2
- 238000006243 chemical reaction Methods 0.000 claims description 2
- 238000003199 nucleic acid amplification method Methods 0.000 claims description 2
- 238000005457 optimization Methods 0.000 claims description 2
- 230000002277 temperature effect Effects 0.000 claims description 2
- 238000012360 testing method Methods 0.000 claims description 2
- 230000008859 change Effects 0.000 abstract description 11
- 230000032683 aging Effects 0.000 description 3
- 230000000694 effects Effects 0.000 description 3
- 230000009286 beneficial effect Effects 0.000 description 1
- 238000004891 communication Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000011160 research Methods 0.000 description 1
Classifications
-
- 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
-
- 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
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03F—AMPLIFIERS
- H03F3/00—Amplifiers with only discharge tubes or only semiconductor devices as amplifying elements
- H03F3/189—High frequency amplifiers, e.g. radio frequency amplifiers
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03F—AMPLIFIERS
- H03F3/00—Amplifiers with only discharge tubes or only semiconductor devices as amplifying elements
- H03F3/20—Power amplifiers, e.g. Class B amplifiers, Class C amplifiers
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03F—AMPLIFIERS
- H03F2200/00—Indexing scheme relating to amplifiers
- H03F2200/447—Indexing scheme relating to amplifiers the amplifier being protected to temperature influence
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03F—AMPLIFIERS
- H03F2200/00—Indexing scheme relating to amplifiers
- H03F2200/451—Indexing scheme relating to amplifiers the amplifier being a radio frequency amplifier
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02D—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN INFORMATION AND COMMUNICATION TECHNOLOGIES [ICT], I.E. INFORMATION AND COMMUNICATION TECHNOLOGIES AIMING AT THE REDUCTION OF THEIR OWN ENERGY USE
- Y02D30/00—Reducing energy consumption in communication networks
- Y02D30/70—Reducing energy consumption in communication networks in wireless communication networks
Abstract
The invention discloses a piecewise linear digital predistortion system and a method for temperature compensation of a power amplifier, wherein the system comprises the following steps: using a single frequency radio frequency signal as an input signal to a radio frequency power amplifierAnd obtain a feedback signal z1 k (j) The method comprises the steps of carrying out a first treatment on the surface of the The N are divided into<，z1 k (j)>The corresponding relation is divided into M sections, and a primary term coefficient a is given out in each section 1m Sum constant term a 0m The method comprises the steps of carrying out a first treatment on the surface of the Selecting different temperature points, and repeating the steps to obtain a plurality of results at different temperatures; fitting to obtain a 1m And a 0m Temperature dependenceIs, a 1m (T)=f 1 (T)，a 1m (T)=f 2 (T); in the actual operation phase, the temperature of the radio frequency power amplifier is tested in relation a 1m (T)=f 1 (T)、a 1m (T)=f 2 (T) calculating the parameter a based on 1m And a 0m . The invention helps to compensate the influence of the temperature change of the radio frequency power amplifier on the parameters of the digital predistortion model.
Description
Technical Field
The invention belongs to the technical field of radio frequency power amplifier compensation, and particularly relates to a piecewise linear digital predistortion system and method for temperature compensation of a power amplifier.
Background
Radio frequency power amplifiers are the most critical and expensive devices (chips) for 5G communication systems. In a 5G radio frequency chip, a high gain, high linearity power amplifier is a key device (chip) in a 5G system, which can ensure that a 5G signal (orthogonal frequency division multiplexing signal) has good linearity in a large bandwidth range, so that it is possible to transmit a high order modulation signal with large bandwidth and low distortion.
However, analog devices of transmitter systems, particularly radio frequency power amplifiers, are relatively susceptible to temperature variations and device aging. The changes of the gain of the rf power amplifier may be caused by the changes of the operating temperature of the rf power amplifier, the aging of the device, etc., and the changes include: 1) A change in the maximum value of the gain of the rf power amplifier, 2) a change in the gain of the amplifier when the power of the input rf signal is low, 2) a change in the saturation gain characteristic of the amplifier when the power of the input rf signal is high, and thus the necessary technique is required to compensate for the temperature effect of the rf power amplifier. The transmitter using the digital predistortion system can solve the problem of the change of the characteristics of the amplifier caused by the working temperature change, the ageing of the analog device and the like, so that some researchers develop researches on the temperature compensation of the radio frequency power amplifier using the digital predistortion technology.
However, there are few solutions that have to pay no attention to the effect of temperature on the radio frequency system. In basic physical principle, the basic parameters of the rf device are temperature dependent, in particular the basic characteristics of the rf amplifier, and are more affected by temperature. This requires that we have to take into account the effect of temperature when actually using the digital predistortion system (model).
Disclosure of Invention
It is an object of the present invention to address at least the above problems and/or disadvantages and to provide at least the advantages described below.
The invention provides a parameter updating method in a piecewise linear digital predistortion model when the temperature of a radio frequency power amplifier changes by combining with the piecewise linear model which is the most common in a digital predistortion system.
It is yet another object of the present invention to provide a power amplifier temperature compensated piecewise linear digital predistortion system and method.
Therefore, the invention provides the following technical scheme:
in a first aspect, a method for piecewise linear digital predistortion for power amplifier temperature compensation is provided, comprising:
step one, at the common temperature of the radio frequency power amplifierIn the interval of radio frequency power +.>N power points of the internal selection RF power amplifier, the power of each power point is +.>，/>K ranges from 0 to N-1;
step two, using the single-frequency radio frequency signal as the input signal of the radio frequency power amplifierK times of passing through the subsequent devices, and the power of the radio frequency signal is +.>Input signal->Each time through a piecewise linear digital predistortion system followed by a digital to analog converter, a modulator, a radio frequency power amplifier, a power coupler modulator and a mode in sequenceThe digital converter obtains a feedback signal z1 k (j)；/>Representing a specific baseband signal +/at each power point>。
Step three, N numbers are processed according to the historical data<，z1 k (j)>The corresponding relation is divided into M sections, and a least square algorithm is used for estimating a first term coefficient a of the piecewise linear digital predistortion model in each piecewise section 1m Sum constant term a 0m Wherein M is an integer, and M is more than or equal to 1 and less than or equal to M;
step four, in the temperature intervalSelecting L different temperature points, and repeating the first to third steps at different temperatures to obtain different temperature results: coefficient of first order term a 1m (T) and constant term a 0m Raw data of (T);
step five, from the recorded first order coefficient a of piecewise linear digital predistortion model under different temperature conditions 1m (T) and constant term coefficient a 0m Fitting in the (T) sequence to obtain a 1m And a 0m Relation to temperature, a 1m (T)=f 1 (T) and a 1m (T)=f 2 (T)；
Step six, in the actual operation stage, testing the real-time temperature T of the radio frequency power amplifier according to the relation a 1m (T)=f 1 (T) and a 1m (T)=f 2 (T) calculating a new parameter a based on 1m And a 0m 。
Preferably, in the method for temperature compensating piecewise linear digital predistortion of a power amplifier, the method for constructing the piecewise linear digital predistortion model comprises the following steps:
determining the segmentation number M of the predistortion model and the segmentation interval parameter，A 0 =0Precision control parameter for each segment interval>According to baseband signal->The pre-distortion model is set for the segment interval of (1):
is the input signal of the digital predistorter, < >>。
Preferably, in the power amplifier temperature compensation piecewise linear digital predistortion method, model parameter a is at different temperatures 11 And a 01 The determining method comprises the following steps:
sequentially sampling a section of baseband signal x (j) which comprises a plurality of sampling points and has a value of A0-x (j) -A1;
initializing model parameters a 11 And a 01 ；
With min|B1 (j) X T (j)-z1(j)| 2 As a goal of the optimization of the number of the cells,for power amplifier->Gain of the segment section; the least square algorithm is adopted to make the model parameters reach the minimum through multiple iterations, and the model parameters a are obtained 11 And a 01 Wherein G1 is a gain estimation value of the combined action of the power amplifier and the feedback link, and B1 (j) = [ a ] 11 (j),a 01 (j)]，X T (j) Transposed to X (j), X (j) = [ X (j), 1]Z1 (j) is a feedback signal of an input baseband signal x (j) after passing through a predistortion model, a digital-to-analog converter, a modulator and a power amplifier in sequence。
Preferably, in the method for temperature compensation of a power amplifier, temperature-dependent model parameters are extracted according to a first method, where the first method includes: (simple Linear fitting)
At the position ofThe interval is fitted with temperature parameters from two coefficient sequences containing L pointsFitting the temperature parameter->And->Wherein the sum of temperature parameters satisfies the following relationship: the four parameters are taken as model parameters extracted from the raw data.
Preferably, in the power amplifier temperature-compensated piecewise linear digital predistortion method, if the temperature-related model parameters are extracted according to the first method, the fitting degree R 2 Less than a certain threshold R 0 2 And extracting the temperature parameter according to a second method, wherein the second method comprises the following steps of: :
1) In interval A m-1 ＜x(j)≤A m In calculating the average of the slope and constant term
2) Calculating the difference delta a of the temperature point value relative to the average value of the slope and the constant term under different temperature conditions 1m (T l ) And Deltaa 0m (T l ) Wherein Δa 1m (T l )＝a 1m (T l )-a 1m_aver ，Δa 0m (T l )＝a 0m (T l )-a 0m_aver ；
3) Setting a coefficient threshold b 1m And b 0m ；
4) When all Deltaa 1m (T l )≤b 1m ，Δa 0m (T l )≤b 0m Comparing all intervals in the step 2) with the average value a of the slope 1m_aver Average value of sum constant term a 0m_aver Is (Δa) 1m (T l ) And Deltaa 0m (T l ) A) and temperature are plotted as a table;
5) When delta a 1m (T l )≥b 1m Or Deltaa 0m (T l )≥b 0m In the temperature interval [ T ] 1 ，T 2 ]Increasing a temperature point T 3 Δa is prepared according to the method of steps 1) to 4) 1m (T l ) And Deltaa 0m (T l ) The relation between the temperature and the temperature is drawn into two tables, and the temperature intervals of the two tables are respectively [ T ] 1 ，T 3 ]And [ T ] 3 ，T 2 ]。
Preferably, in the power amplifier temperature compensated piecewise linear digital predistortion method,the value of (2) is +.>。
Preferably, in the power amplifier temperature compensated piecewise linear digital predistortion method, the following linear fitting method with compensation is used: at the position ofThe interval is fitted with temperature parameters from two coefficient sequences comprising L points +.>And->) Fitting out inTemperature parameter->And->Wherein the temperature parameterAnd->The following relationship is satisfied: />，，/>Wherein->And->Residual errors for fitting data; />、/>、/>And->Four parameters as model parameters extracted from the original data, < >>Andboth sequences act as compensation terms for the linear model.
Preferably, in the power amplifier temperature compensated piecewise linear digital predistortion method, the fitting relation a is obtained as follows 1m (T)=f 1 (T) and a 0m (T)=f 2 (T)：
1) Firstly, extracting a model of the relation between parameters and temperature according to a first method, if the fitting degree R 2 Greater than a certain threshold R 0 2 When the fitting process is terminated, calculating digital predistortion model parameters a under different temperature conditions according to the result obtained by the first method 1m And a 0m ；
2) If the fitting degree R 2 Less than a certain threshold R 0 2 And temperature parameterWhen (I)>Is of a relatively small value, e.g. +.>Extracting temperature parameters according to the second method, and calculating digital predistortion model parameters a under different temperature conditions 1m And a 0m ；
3) If the fitting degree R 2 Less than a certain threshold R 0 2 And temperature parameterWhen the temperature parameters are extracted according to the third method, and the digital predistortion model parameters a under different temperature conditions are calculated 1m And a 0m 。
In a second aspect, there is provided a power amplifier temperature compensated piecewise linear digital predistortion system comprising:
a digital predistortion module for inputting signals based on initial target predistortion coefficientsPerforming digital predistortion processing to obtain a first adjustment signal +.>；
A digital-to-analog converter for converting the first adjustment signalConversion to analog baseband signal->；
Modulator for simulating baseband signalModulating to f1 on the required radio frequency;
the power amplifier module is used for modulating the analog baseband signal on the f1 of the radio frequencyPerforming power amplification processing to obtain a transmitting signal;
the radio frequency signal feedback device is used for feeding back part of the transmitting signals to the transmitting end and sequentially passing through the demodulator and the analog-to-digital converter to obtain feedback signals z1 k (j)。
The embodiment of the invention at least comprises the following beneficial effects:
the invention provides a parameter updating method in a piecewise linear digital predistortion model when the temperature of a radio frequency power amplifier changes by combining with the piecewise linear model which is the most common in a digital predistortion system. The piecewise linear model adopted by the invention is a linear model for each input amplitude interval, and the requirements for slope deviation are not greatly different. The linear interval division of the piecewise linear model and the gain coefficients of the segments may change due to temperature changes. This change is recorded to form a linear interval division and a temperature dependent gain factor for each segment that will help compensate for the effect of the rf power amplifier temperature change on the digital predistortion model parameters.
Additional advantages, objects, and features of embodiments of the invention will be set forth in part in the description which follows and in part will become apparent to those having ordinary skill in the art upon examination of the following or may be learned from practice of embodiments of the invention.
Drawings
FIG. 1 is a graph showing the relationship between the first order term coefficient of the first segment interval and temperature change under the noise-free condition in one embodiment of the present invention.
FIG. 2 is a graph showing the relationship between the first order coefficient and the temperature of the second segment under the noise-free condition in one embodiment of the present invention.
FIG. 3 is a graph showing the relationship between the first order coefficient and the temperature of the third segment under the noise-free condition according to an embodiment of the present invention.
FIG. 4 is a graph showing the relationship between the first order coefficient and the temperature in the first segment region under the noisy condition according to one embodiment of the present invention.
FIG. 5 is a graph showing the relationship between the first order coefficient and the temperature of the second segment under the noise condition according to one embodiment of the present invention.
FIG. 6 is a graph showing the relationship between the first order coefficient and the temperature of the third segment under the noisy condition according to one embodiment of the present invention.
FIG. 7 is a graph showing the relationship between the first order coefficient and the temperature of the second segment region when the noise is large according to an embodiment of the present invention.
Detailed Description
Embodiments of the invention will be described in further detail below with reference to the drawings to enable those skilled in the art to practice the invention by reference to the description.
1. The embodiment discloses a specific method for determining the parameter variation along with the temperature in a digital predistortion model, which is divided into two situations of no noise and noise.
1) According to the measurement for the radio frequency amplifier, the amplitude is measured as followsWithin the range of (2), 100 amplitude points are taken, and the amplitude of the nth voltage point is +.>The method comprises the steps of carrying out a first treatment on the surface of the The interval parameters of the voltage are as follows: />。
2) Gain of each amplitude interval of the radio frequency power amplifier is obtained through a least square fitting method。
，/>，/>。
The digital predistortion model is:
the parameter values in the model are:，/>，/>；
，/>，/>。
however, the parameters in the model are values of parameters obtained according to the least square method, which are values at a specific temperature, and in a real system, the parameters are affected by the temperature.
To obtain different temperaturesData on parameters the following experiment needs to be completed. In the temperature intervalIn T 1 =25℃，T 2 =60 ℃,8 different temperature points were selected, with a temperature interval of 5 ℃.
1.1 case without noise
It is assumed that the noise in the system is small, i.e. handled as a noise free case. The model parameter values of the initial temperature obtained according to the method are as follows:
，/>，/>；/>，/>，/>。
the values of the first segment interval polynomial linear fit coefficients as a function of temperature are as follows:
a 11 (25℃)=1/30.0=0.03333;
a 11 (30 ℃) 1/29.6= 0.03378; temperature increment of linear fitting coefficient: 4.5*10 -4
a 11 (35 ℃) 1/29.2= 0.03425; temperature increment of linear fitting coefficient: 4.6*10 -4
a 11 (40 ℃) 1/28.8= 0.03472; temperature increment of linear fitting coefficient: 4.7*10 -4
a 11 (45 ℃) 1/28.4= 0.03521; temperature increment of linear fitting coefficient: 4.9*10 -4
a 11 (50 ℃) 1/28.0= 0.03571; temperature of the linear fitting coefficientIncrement: 5.0*10 -4
a 11 (55 ℃) 1/27.6= 0.03623; temperature increment of linear fitting coefficient: 5.2*10 -4
a 11 (60 ℃) 1/27.2= 0.03676; temperature increment of linear fitting coefficient: 5.3*10 -4
From FIG. 1, the temperature coefficient C can be known 11 =0.98*10 -4 /℃。
The value of the second-stage interval coefficient as a function of temperature:
a 12 (25℃)=1/20.0=0.05;
a 12 (30 ℃) 1/19.7= 0.0576; temperature increment of linear fitting coefficient: 7.6*10 -4
a 12 (35 ℃) 1/19.4= 0.05155; temperature increment of linear fitting coefficient: 7.8*10 -4
a 12 (40 ℃) 1/19.1= 0.05236; temperature increment of linear fitting coefficient: 8.1*10 -4
a 12 (45 ℃) 1/18.8= 0.05319; temperature increment of linear fitting coefficient: 8.4*10 -4
a 12 (50 ℃) 1/18.5= 0.05405; temperature increment of linear fitting coefficient: 8.6*10 -4
a 12 (55 ℃) 1/18.2= 0.05495; temperature increment of linear fitting coefficient: 8.9*10 -4
a 12 (60 ℃) 1/17.9= 0.05587; temperature increment of linear fitting coefficient: 9.2*10 -4
From FIG. 2, the temperature coefficient C can be known 12 =1.68*10 -4 /℃。
The value of the third segment interval coefficient as a function of temperature:
a 13 (25℃)=1/12.0=0.083;
a 13 (30 ℃) 1/11.8=0.085, temperature increment of linear fitting coefficient: 14.1*10 -4
a 13 (35 ℃) 1/11.6=0.086; temperature increment of linear fitting coefficient: 14.6*10 -4
a 13 (40 ℃) 1/11.4=0.088, temperature increment of linear fitting coefficient: 15.1*10 -4
a 13 (45 ℃) 1/11.2=0.089, temperature increment of linear fitting coefficient: 15.7*10 -4
a 13 (50 ℃) 1/11.0=0.091, temperature increment of linear fitting coefficient: 16.2*10 -4
a 13 (55 ℃) 1/10.8=0.093, temperature increment of linear fitting coefficient: 16.8*10 -4
a 13 (60 ℃) 1/10.6=0.094, temperature increment of linear fitting coefficient: 17.5*10 -4
From FIG. 3, the temperature coefficient C can be known 13 =3.14*10 -4 /℃。
1.2 Noisy conditions
The model parameter values of the initial temperature obtained according to the method are as follows:
，/>，/>；/>，/>，。
the values of the first segment interval polynomial linear fit coefficients as a function of temperature are as follows:
a 11 (25℃)=1/30.0925=0.03323;
a 11 (30 ℃) =1/29.7127 = 0.03366, temperature increment of linear fitting coefficient: 4.3*10 -4
a 11 (35 ℃) 1/29.2018 = 0.03424, temperature increment of linear fitting coefficient: 5.8*10 -4
a 11 (40 ℃) 1/28.8434 = 0.03467, temperature increment of the linear fitting coefficient：4.3*10 -4
a 11 (45 ℃) 1/28.5443 = 0.03503, temperature increment of linear fitting coefficient: 3.6*10 -4
a 11 (50 ℃) 1/27.9821 = 0.03574, temperature increment of linear fitting coefficient: 7.1*10 -4
a 11 (55 ℃) 1/27.4592 = 0.03642, temperature increment of linear fitting coefficient: 6.8*10 -4
a 11 (60 ℃) 1/27.3174 = 0.03661, temperature increment of linear fitting coefficient: 1.9*10 -4
From FIG. 4, the temperature coefficient C can be known 11 =1.0*10 -4 Constant term 0.03067 of temperature, linear fitness R 2 =0.9916。
Coefficient residuals of 8 different temperature points at an interval of 25 ℃ to 60 ℃ and 5 DEG CThe values are as follows:
the value of the second-stage interval coefficient as a function of temperature:
a 12 (25℃)=1/20.059=0.04985;
a 12 (30 ℃) =1/19.6348 = 0.05093, temperature increment of linear fitting coefficient: 10.8*10 -4
a 12 (35 ℃) 1/19.6237 = 0.05096, temperature increment of linear fitting coefficient: 0.3*10 -4
a 12 (40 ℃) =1/18.9759 = 0.05270, temperature increment of linear fitting coefficient: 17.4*10 -4
a 12 (45 ℃) 1/18.8686 = 0.05300, temperature increment of linear fitting coefficient: 3.0*10 -4
a 12 (50 ℃) 1/18.5472 = 0.05392, temperature increment of linear fitting coefficient: 9.2*10 -4
a 12 (55 ℃) 1/18.1493 = 0.05510, temperature increment of linear fitting coefficient: 11.8*10 -4
a 12 (60 ℃) 1/17.7390 = 0.05637, temperature increment of linear fitting coefficient: 12.7*10 -4
From FIG. 5, the temperature coefficient C can be known 12 =1.8*10 -4 Constant term 0.0452 of temperature, linear fitness R 2 =0.9764。
Coefficient residuals of 8 different temperature points at an interval of 25 ℃ to 60 ℃ and 5 DEG CThe values are as follows:
。
the value of the third segment interval coefficient as a function of temperature:
a 13 (25℃)=1/11.8101=0.08467;
a 13 (30 ℃) =1/11.7684 = 0.08497, temperature increment of linear fitting coefficient: 14.1*10 -4
a 13 (35 ℃) 1/11.4736 = 0.08716, temperature increment of linear fitting coefficient: 14.6*10 -4
a 13 (40 ℃) =1/11.4903 = 0.08703, temperature increment of linear fitting coefficient: 15.1*10 -4
a 13 (45 ℃) 1/11.1481 = 0.08970, temperature increment of linear fitting coefficient: 15.7*10 -4
a 13 (50 ℃) 1/11.1366 = 0.08979, temperature increment of linear fitting coefficient: 16.2*10 -4
a 13 (55 ℃) 1/10.8937 = 0.09180, temperature increment of linear fitting coefficient: 16.8*10 -4
a 13 (60 ℃) 1/10.6284 = 0.09409, temperature increment of linear fitting coefficient: 17.5*10 -4
From FIG. 6, it can be seen that the temperature coefficient C 13 =2.63*10 -4 Constant term 0.07746 of temperature, linear fitness R 2 =0.9572。
Coefficient residuals of 8 different temperature points at an interval of 25 ℃ to 60 ℃ and 5 DEG CThe values are as follows:
in the first case, since the linear fitting degree is high in the three sections as a whole, only the linear fitting coefficient of the temperature needs to be recorded.
And in the second case, if a linear fitting coefficient R is set 2 Threshold R of (2) 0 2 If the temperature is 0.976, the first interval and the second interval only need to record the linear fitting coefficient of the temperature, and the third interval needs to increase the coefficient residual errorThe numerical value is used as a compensation term. If the linear fitting coefficient R is set 2 Threshold R of (2) 0 2 If the temperature is 0.98, the first interval only needs to record the linear fitting coefficient of the temperature, and the second interval and the third interval need to increase the coefficient residual error +.>And->The numerical value is used as a compensation term.
1.3 Is noisy and has a large interference term
This is an extreme case, as shown in FIG. 7, where the temperature coefficient C of the second segment interval 12 =0.724*10 -4 /℃，，/>，R 2 =0.088. At this time, the description of the relationship of the digital predistortion parameters with the temperature change may be performed according to the second method.
The first order coefficients of the temperature points are:
a 12 (25℃)=0.0523; a 12 (30℃)=0.0540; a 12 (35℃)=0.0532;
a 12 (40℃)=0.0505;a 12 (45℃)=0.0508; a 12 (50℃)=0.0523;
a 12 (55℃)=0.060; a 12 (60℃)=0.0528;
with an average value of a 12_aver =0.05324;
The residual error of the primary term coefficient of each temperature point is as follows:
。
it should be noted that, in the above processes and the system structures, not all steps and modules are necessary, and some steps and units may be omitted according to actual needs. The order of execution of the steps is not fixed and may be determined as desired. The device structures described in the above embodiments may be physical structures or logical structures. A certain module or unit may be implemented by the same physical entity, a certain module or unit may be implemented by a plurality of physical entities respectively, and a certain module or unit may also be implemented by a plurality of components in a plurality of independent devices together.
Although the embodiments of the examples of the present invention have been disclosed above, they are not limited to the use listed in the specification and the embodiments. It can be fully adapted to various fields suitable for embodiments of the present invention. Additional modifications will readily occur to those skilled in the art. Therefore, embodiments of the invention are not limited to the specific details and illustrations shown and described herein, without departing from the general concepts defined in the claims and their equivalents.
Claims (9)
1. A method for temperature compensated piecewise linear digital predistortion of a power amplifier, comprising:
step one, at the common temperature T of the radio frequency power amplifier 0 In the interval of radio frequency powerN power points of the internal selection RF power amplifier, the power of each power point is +.>，/>K ranges from 0 to N-1;
step two, using the single-frequency radio frequency signal as the input signal of the radio frequency power amplifierK times of passing through the subsequent devices, and the power of the radio frequency signal is +.>Input signal->Each time the feedback signal z1 is obtained through the piecewise linear digital predistortion system, then sequentially through the digital-to-analog converter, the modulator, the radio frequency power amplifier, the power coupler modulator and the analog-to-digital converter k (j)；
Step three, N<，z1 k (j)>The corresponding relation is divided into M sections, and a first term coefficient a of a piecewise linear digital predistortion model is estimated in each piecewise section 1m Sum constant term a 0m Wherein M is an integer, and M is more than or equal to 1 and less than or equal to M;
step four, in the temperature intervalSelecting L different temperature points, and repeating the first to third steps at different temperatures to obtain different temperature results: coefficient of first order term a 1m (T) and constant term a 0m Raw data of (T);
step five, from the recorded first order coefficient a of piecewise linear digital predistortion model under different temperature conditions 1m (T) and constant term coefficient a 0m Fitting in the (T) sequence to obtain a 1m And a 0m Relation to temperature, a 1m (T)=f 1 (T) and a 1m (T)=f 2 (T)；
Step six, in the actual operation stage, testing the real-time temperature T of the radio frequency power amplifier according to the relation a 1m (T)=f 1 (T) and a 1m (T)=f 2 (T) calculating a new parameter a based on 1m And a 0m 。
2. The method for temperature-compensated piecewise linear digital predistortion of a power amplifier of claim 1 wherein said method for constructing a piecewise linear digital predistortion model comprises the steps of:
determining the segmentation number M of the predistortion model and the segmentation interval parameter，A 0 =0, and the precision control parameter for each segment interval +.>According to baseband signal->The pre-distortion model is set for the segment interval of (1):
is the input signal of the digital predistorter, < >>。
3. The method for temperature compensated piecewise linear digital predistortion of a power amplifier of claim 2 wherein model parameter a is at different temperatures 11 And a 01 The determining method comprises the following steps:
sequentially sampling a section of baseband signal x (j) which comprises a plurality of sampling points and has a value of A0-x (j) -A1;
initializing model parameters a 11 And a 01 ；
With min|B1 (j) X T (j)-z1(j)| 2 As a goal of the optimization of the number of the cells,for power amplifier->Gain of the segment section; the least square algorithm is adopted to make the model parameters reach the minimum through multiple iterations, and the model parameters a are obtained 11 And a 01 Wherein G1 is a gain estimation value of the combined action of the power amplifier and the feedback link, and B1 (j) = [ a ] 11 (j),a 01 (j)]，X T (j) Transposed to X (j), X (j) = [ X (j), 1]Z1 (j) is a feedback signal of an input baseband signal x (j) after passing through a predistortion model, a digital-to-analog converter, a modulator and a power amplifier in sequence.
4. The power amplifier temperature compensated piecewise linear digital predistortion method of claim 2 wherein temperature dependent model parameters are extracted according to a first method comprising:
at the position ofThe interval is fitted with temperature parameters from two coefficient sequences containing L pointsFitting the temperature parameter->And->Wherein the sum of temperature parameters satisfies the following relationship: the four parameters are taken as model parameters extracted from the raw data.
5. The power amplifier temperature compensated piecewise linear digital predistortion method of claim 4 wherein the fitting degree R if temperature dependent model parameters are extracted according to said first method 2 Less than a certain threshold R 0 2 And extracting the temperature parameter according to a second method, wherein the second method comprises the following steps of:
1) In interval A m-1 ＜x(j)≤A m In calculating the average of the slope and constant termAnd
2) Calculating the difference delta a of the temperature point value relative to the average value of the slope and the constant term under different temperature conditions 1m (T l ) And Deltaa 0m (T l ) Wherein Δa 1m (T l )＝a 1m (T l )-a 1m_aver， Δa 0m (T l )＝a 0m (T l )-a 0m_aver ；
3) Setting a coefficient threshold b 1m And b 0m ；
4) When all Deltaa 1m (T l )≤b 1m ，Δa 0m (T l )≤b 0m Comparing all intervals in the step 2) with the average value a of the slope 1m_aver Average value of sum constant term a 0m_aver Is (Δa) 1m (T l ) And Deltaa 0m (T l ) A) and temperature are plotted as a table;
5) When delta a 1m (T l )≥b 1m Or Deltaa 0m (T l )≥b 0m In the temperature interval [ T ] 1 ,T 2 ]Increasing a temperature point T 3 Δa is prepared according to the method of steps 1) to 4) 1m (T l ) And Deltaa 0m (T l ) The relation between the temperature and the temperature is drawn into two tables, and the temperature intervals of the two tables are respectively [ T ] 1 ,T 3 ]And [ T ] 3 ,T 2 ]。
6. A method for temperature compensated piecewise linear digital predistortion of a power amplifier as set out in claim 5,the value of (2) is +.>。
7. The method of compensating for the temperature effects of a radio frequency power amplifier using a piecewise linear digital predistortion model of claim 2 wherein the following linear fitting method with compensation is used: at the position ofThe interval is fitted with temperature parameters from two coefficient sequences comprising L points +.>And->) Fitting the temperature parameterAnd->Wherein the temperature parameter->And->The following relationship is satisfied: />，， />Wherein->And->Residual errors for fitting data; />、/>、/>And->Four parameters as model parameters extracted from the original data, < >>Andboth sequences act as compensation terms for the linear model.
8. A power amplifier temperature compensated piecewise linear digital as set out in claim 7The predistortion method is characterized in that the fitting relation a is obtained according to the following method 1m (T)=f 1 (T) and a 0m (T)=f 2 (T)：
1) Firstly, extracting a model of the relation between parameters and temperature according to a first method, if the fitting degree R 2 Greater than a certain threshold R 0 2 When the fitting process is terminated, the digital predistortion model parameters a under different temperature conditions are calculated according to the results obtained by the first method of claim 4 1m And a 0m ；
2) If the fitting degree R 2 Less than a certain threshold R 0 2 And temperature parameterWhen the temperature parameters are extracted according to the second method, and the digital predistortion model parameters a under different temperature conditions are calculated 1m And a 0m ；
3) If the fitting degree R 2 Less than a certain threshold R 0 2 And temperature parameterWhen the temperature parameters are extracted according to the third method, and the digital predistortion model parameters a under different temperature conditions are calculated 1m And a 0m 。
9. A power amplifier temperature compensated piecewise linear digital predistortion system comprising:
a digital predistortion module for inputting signals based on initial target predistortion coefficientsPerforming digital predistortion processing to obtain a first adjustment signal +.>；
A digital-to-analog converter for converting the first adjustment signalConversion to analog baseband signal->；
Modulator for simulating baseband signalModulating to f1 on the required radio frequency;
the power amplifier module is used for modulating the analog baseband signal on the f1 of the radio frequencyPerforming power amplification processing to obtain a transmitting signal;
the radio frequency signal feedback device is used for feeding back part of the transmitting signals to the transmitting end and sequentially passing through the demodulator and the analog-to-digital converter to obtain feedback signals z1 k (j)。
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202310871150.9A CN117040450A (en) | 2023-07-17 | 2023-07-17 | Piecewise linear digital predistortion system and method for temperature compensation of power amplifier |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202310871150.9A CN117040450A (en) | 2023-07-17 | 2023-07-17 | Piecewise linear digital predistortion system and method for temperature compensation of power amplifier |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN117040450A true CN117040450A (en) | 2023-11-10 |
Family
ID=88643850
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202310871150.9A Pending CN117040450A (en) | 2023-07-17 | 2023-07-17 | Piecewise linear digital predistortion system and method for temperature compensation of power amplifier |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN117040450A (en) |
Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6081158A (en) * | 1997-06-30 | 2000-06-27 | Harris Corporation | Adaptive pre-distortion apparatus for linearizing an amplifier output within a data transmission system |
| US20010050592A1 (en) * | 1999-07-13 | 2001-12-13 | Wright Andrew S. | Amplifier measurement and modeling processes for use in generating predistortion parameters |
| US7058369B1 (en) * | 2001-11-21 | 2006-06-06 | Pmc-Sierra Inc. | Constant gain digital predistortion controller for linearization of non-linear amplifiers |
| US20100225390A1 (en) * | 2008-11-11 | 2010-09-09 | Axis Network Technology Ltd. | Resource Efficient Adaptive Digital Pre-Distortion System |
| CN101873284A (en) * | 2010-05-19 | 2010-10-27 | 京信通信系统（中国）有限公司 | Digital predistortion system and temperature compensation method in digital predistortion system |
| CN102340283A (en) * | 2010-07-14 | 2012-02-01 | 大唐移动通信设备有限公司 | Method and device for envelope tracking |
| CN114400979A (en) * | 2021-12-02 | 2022-04-26 | 西安邮电大学 | System and method for improving digital predistortion of short wave interaction and harmonic distortion |
-
2023
- 2023-07-17 CN CN202310871150.9A patent/CN117040450A/en active Pending
Patent Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6081158A (en) * | 1997-06-30 | 2000-06-27 | Harris Corporation | Adaptive pre-distortion apparatus for linearizing an amplifier output within a data transmission system |
| US20010050592A1 (en) * | 1999-07-13 | 2001-12-13 | Wright Andrew S. | Amplifier measurement and modeling processes for use in generating predistortion parameters |
| US7058369B1 (en) * | 2001-11-21 | 2006-06-06 | Pmc-Sierra Inc. | Constant gain digital predistortion controller for linearization of non-linear amplifiers |
| US20100225390A1 (en) * | 2008-11-11 | 2010-09-09 | Axis Network Technology Ltd. | Resource Efficient Adaptive Digital Pre-Distortion System |
| CN101873284A (en) * | 2010-05-19 | 2010-10-27 | 京信通信系统（中国）有限公司 | Digital predistortion system and temperature compensation method in digital predistortion system |
| CN102340283A (en) * | 2010-07-14 | 2012-02-01 | 大唐移动通信设备有限公司 | Method and device for envelope tracking |
| CN114400979A (en) * | 2021-12-02 | 2022-04-26 | 西安邮电大学 | System and method for improving digital predistortion of short wave interaction and harmonic distortion |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN101175061B (en) | Self-adapting digital predistortion method and apparatus for OFDM transmitter | |
| KR101789924B1 (en) | Device and method for adaptive digital pre-distortion | |
| KR20140096126A (en) | System linearization | |
| EP2202879B1 (en) | A predistortion apparatus and predistortion method | |
| CN106506417B (en) | Narrow-band feedback digital predistortion system and method | |
| US20110270590A1 (en) | Nonlinear identification using compressed sensing and minimal system sampling | |
| Hekkala et al. | Adaptive time misalignment compensation in envelope tracking amplifiers | |
| CN102143108A (en) | Improved self-adaption predistortion technology | |
| EP2795792B1 (en) | Adaptive predistortion for a non-linear subsystem based on a model as a concatenation of a non-linear model followed by a linear model | |
| Braithwaite et al. | General principles and design overview of digital predistortion | |
| US10756682B1 (en) | Compensating for transmitter nonlinearities | |
| US20120154040A1 (en) | Predistorter for compensating for nonlinear distortion and method thereof | |
| CN113949350A (en) | Digital predistortion method and system based on baseband-radio frequency joint optimization | |
| WO2010102439A1 (en) | A digital predistortion circuit with extended operating range and a method thereof | |
| CN103929136A (en) | Broadband mobile communication LTE system transmitter power amplifier predistortion processing method | |
| CN117040450A (en) | Piecewise linear digital predistortion system and method for temperature compensation of power amplifier | |
| US20130163694A1 (en) | Architecture of a low bandwidth predistortion system for non-linear rf components | |
| US20040258176A1 (en) | Precorrection of nonlinear distortion with memory | |
| EP3249809B1 (en) | Method and apparatus for determining validity of samples for digital pre-distortion apparatus | |
| CN115913140B (en) | Piecewise polynomial digital predistortion device and method for controlling operation precision | |
| KR100625445B1 (en) | Prediction apparatus with a varying order and its control method | |
| CN102403960B (en) | The method of predistortion and device and distortion exciter are carried out to exciter | |
| CN116054758B (en) | Parameter updating method of piecewise linear digital predistortion model and predistortion system | |
| RU2731128C1 (en) | Method for combined digital linearization of power amplifier and quadrature modulator | |
| CN115632615B (en) | Digital predistortion method and system |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination |