CN106685868B - Adjacent multiband digital predistortion system and method - Google Patents

Adjacent multiband digital predistortion system and method Download PDF

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CN106685868B
CN106685868B CN201710001793.2A CN201710001793A CN106685868B CN 106685868 B CN106685868 B CN 106685868B CN 201710001793 A CN201710001793 A CN 201710001793A CN 106685868 B CN106685868 B CN 106685868B
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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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    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L25/00—Baseband systems
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Abstract

本发明公开了一种相邻多频带数字预失真系统与方法，包括多带数字预失真模块、加法器、功放和多带预失真参数计算模块；所述的多带数字预失真模块包括多个并行运行的数字预失真器；每个数字预失真器同时处理来自不同信号源的信号，数字预失真器的输出端通过各自的射频通道与加法器连接；加法器的输出端与功放连接，功放的输出端与天线连接；所述功放的输出端还通过反馈通道与多带预失真参数计算模块连接，多带预失真参数计算模块的输出端分别与每一个数字预失真器连接，由多带预失真参数计算模块计算得到预失真参数向量，对各个数字预失真器进行参数调整。本发明能够对不同频带对应的数字预失真器分别进行调整，进而可以有效抑制近距离多频带功放的非线性是失真。

Figure 201710001793

The invention discloses an adjacent multi-band digital pre-distortion system and method, comprising a multi-band digital pre-distortion module, an adder, a power amplifier and a multi-band pre-distortion parameter calculation module; the multi-band digital pre-distortion module includes a plurality of Digital predistorter running in parallel; each digital predistorter simultaneously processes signals from different signal sources, and the output of the digital predistorter is connected to the adder through its respective RF channel; the output of the adder is connected to the power amplifier, and the power amplifier The output end of the power amplifier is connected with the antenna; the output end of the power amplifier is also connected with the multi-band pre-distortion parameter calculation module through the feedback channel, and the output end of the multi-band pre-distortion parameter calculation module is respectively connected with each digital pre-distorter. The predistortion parameter calculation module calculates the predistortion parameter vector, and adjusts the parameters of each digital predistorter. The present invention can adjust the digital predistorters corresponding to different frequency bands respectively, thereby effectively suppressing the nonlinearity and distortion of the short-range multi-band power amplifier.

Figure 201710001793

Description

一种相邻多频带数字预失真系统与方法A system and method for adjacent multi-band digital predistortion

技术领域technical field

本发明涉及一种相邻多频带数字预失真系统与方法。The present invention relates to an adjacent multi-band digital predistortion system and method.

背景技术Background technique

多频带功率放大器的产生，使得多个不同频段的信号可以复用同一个功率放大器，从而节省成本。然而，如何对这多个信号进行预失真处理，以消除功率放大器所固有的非线性失真，是一个重点问题。The generation of multi-band power amplifiers enables multiple signals of different frequency bands to be multiplexed with the same power amplifier, thereby saving costs. However, how to pre-distort these multiple signals to eliminate the inherent nonlinear distortion of the power amplifier is a key issue.

若使用传统单频带的数字预失真方法来对多个频带信号进行预失真处理，它需要把所有频带信号整合为一频道的信号，从而使得信号带宽非常宽。其带来的后果是需要使用高采样率的DAC和ADC，造成成本急剧上升。If the traditional single-band digital pre-distortion method is used to perform pre-distortion processing on multiple frequency band signals, it needs to integrate all frequency band signals into a signal of one channel, so that the signal bandwidth is very wide. The consequence of this is the need to use high sampling rate DACs and ADCs, resulting in a dramatic increase in cost.

传统非相邻多频带的数字预示真方法，则分别对各个频段信号进行单独的预失真处理操作。由于各个频带间隔较大，其频带间的交叉调制影响被忽略了。从而影响相邻多频带数字预失真效果。In the traditional non-adjacent multi-band digital prediction method, separate pre-distortion processing operations are performed on the signals of each frequency band. Due to the large spacing of each frequency band, the effect of cross-modulation between the frequency bands is ignored. Thereby affecting the adjacent multi-band digital pre-distortion effect.

发明内容SUMMARY OF THE INVENTION

本发明的目的在于克服现有技术的不足，提供一种相邻多频带数字预失真系统与方法，能够分别校正功放各个频带的非线性失真。The purpose of the present invention is to overcome the deficiencies of the prior art, and to provide an adjacent multi-band digital predistortion system and method, which can respectively correct the nonlinear distortion of each frequency band of the power amplifier.

本发明的目的是通过以下技术方案来实现的：一种相邻多频带数字预失真系统，包括多带数字预失真模块、加法器、功放和多带预失真参数计算模块；The object of the present invention is achieved through the following technical solutions: an adjacent multi-band digital pre-distortion system, comprising a multi-band digital pre-distortion module, an adder, a power amplifier and a multi-band pre-distortion parameter calculation module;

所述的多带数字预失真模块包括多个并行运行，且与功放不同频带一一对应数字预失真器；每个数字预失真器同时处理来自不同信号源的信号，数字预失真器的输出端通过各自的射频通道与加法器连接；加法器的输出端与功放连接，功放的输出端与天线连接；所述功放的输出端还通过反馈通道与多带预失真参数计算模块连接，多带预失真参数计算模块的输出端分别与每一个数字预失真器连接，由多带预失真参数计算模块计算得到预失真参数向量，对各个数字预失真器进行参数调整。The multi-band digital predistortion module includes a plurality of digital predistorters operating in parallel and corresponding to different frequency bands of the power amplifier; each digital predistorter simultaneously processes signals from different signal sources, and the output end of the digital predistorter Connect with the adder through respective radio frequency channels; the output end of the adder is connected with the power amplifier, and the output end of the power amplifier is connected with the antenna; the output end of the power amplifier is also connected with the multi-band pre-distortion parameter calculation module through the feedback channel, and the multi-band pre-distortion parameter calculation module The output end of the distortion parameter calculation module is respectively connected with each digital predistorter, the multiband predistortion parameter calculation module calculates the predistortion parameter vector, and adjusts the parameters of each digital predistorter.

所述的射频通道包括数模转换模块和上变频模块，数模转换模块的输入端与数字预失真器连接，数模转换模块的输出端与上变频模块连接，上变频模块的输出端与加法器连接。The radio frequency channel includes a digital-to-analog conversion module and an up-conversion module, the input end of the digital-to-analog conversion module is connected to the digital predistorter, the output end of the digital-to-analog conversion module is connected to the up-conversion module, and the output end of the up-conversion module is connected to the addition device connection.

所述的反馈通道包括下变频模块和模数转换模块，下变频模块的输入端与功放连接，下变频模块的输出端与模数转换模块连接。The feedback channel includes a down-conversion module and an analog-to-digital conversion module, the input end of the down-conversion module is connected to the power amplifier, and the output end of the down-conversion module is connected to the analog-to-digital conversion module.

所述的反馈通道还包括设置于下变频模块与模数转换模块之间的滤波器。The feedback channel also includes a filter arranged between the down-conversion module and the analog-to-digital conversion module.

所述的多带预失真参数计算模块包括：The multi-band predistortion parameter calculation module includes:

多带非线性模型提取单元，用于根据各个数字预失真器输出的信号和来自反馈通道的反馈信号，提取多带非线性功放模型；The multi-band nonlinear model extraction unit is used to extract the multi-band nonlinear power amplifier model according to the output signal of each digital predistorter and the feedback signal from the feedback channel;

预失真参数提取单元，用于根据多带非线性功放模型和各个数字预失真器输出的信号提取每个数字预失真器的预失真参数向量。The predistortion parameter extraction unit is used for extracting the predistortion parameter vector of each digital predistorter according to the multi-band nonlinear power amplifier model and the signal output by each digital predistorter.

一种相邻多频带数字预失真方法，包括以下步骤：An adjacent multi-band digital predistortion method, comprising the following steps:

S1.利用多带数字预失真模块中的每个数字预失真器同时处理来自不同信号源的信号u1(n),u2(n),...,uN(n)，得到多个预失真信号x1(n),x2(n),...,xN(n)，信号源的个数和预失真器的个数相等，均为N，得到的预失真信号x1(n),x2(n),...,xN(n)中包含了功放的非线性失真特性的逆特性，能够降低或抵消功放的非线性失真；S1. Use each digital predistorter in the multi-band digital predistortion module to process signals u 1 (n), u 2 (n), . . . , u N (n) from different signal sources simultaneously to obtain multiple Predistortion signal x 1 (n),x 2 (n),...,x N (n), the number of signal sources is equal to the number of predistorters, both are N, the obtained predistortion signal x 1 (n),x 2 (n),...,x N (n) contains the inverse characteristics of the nonlinear distortion characteristics of the power amplifier, which can reduce or cancel the nonlinear distortion of the power amplifier;

S2.将各个预失真器得到的预失真信号x1(n),x2(n),...,xN(n)分别通过各自的射频通道后合成同一路信号

Figure BDA0001201715450000021
并送入功放进行放大后，得到信号
Figure BDA0001201715450000022
并通过天线进行发射；S2. Synthesize the same signal after passing the predistorted signals x 1 (n), x 2 (n),...,x N (n) obtained by each predistorter through their respective radio frequency channels.
Figure BDA0001201715450000021
And send it to the power amplifier for amplification, get the signal
Figure BDA0001201715450000022
and transmit through the antenna;

S3.采集功放输出的信号

Figure BDA0001201715450000023
通过反馈通道处理后得到数字信号y(n)；S3. Collect the signal output by the power amplifier
Figure BDA0001201715450000023
The digital signal y(n) is obtained after processing through the feedback channel;

S4.利用数字信号y(n)和功率放大器的各路输入信号x1(n),x2(n),...,xN(n)，提取预失真参数向量，对各个数字预失真器进行调整。S4. Using the digital signal y(n) and each input signal x 1 (n), x 2 (n),..., x N (n) of the power amplifier, extract the predistortion parameter vector, and analyze the predistortion parameters for each digital predistortion device to adjust.

所述的步骤S1包括以下子步骤：The described step S1 includes the following sub-steps:

S11.对各个信号源的信号u1(n),u2(n),...,uN(n)，进行非线性处理得到与各个数字预失真器对应的非线性向量；S11. Perform nonlinear processing on the signals u 1 (n), u 2 (n), . . . , u N (n) of each signal source to obtain a nonlinear vector corresponding to each digital predistorter;

S12.将各个数字预失真器的预失真参数向量与对应的非线性向量的转置相乘，得到各个数字预失真器的输出信号：S12. Multiply the predistortion parameter vector of each digital predistorter with the transpose of the corresponding nonlinear vector to obtain the output signal of each digital predistorter:

第1个预失真器的输出信号为：

Figure BDA0001201715450000024
The output signal of the first predistorter is:
Figure BDA0001201715450000024

第2个预失真器的输出信号为：

Figure BDA0001201715450000025
The output signal of the second predistorter is:
Figure BDA0001201715450000025

……...

第N个预失真器的输出信号为：

Figure BDA0001201715450000026
The output signal of the Nth predistorter is:
Figure BDA0001201715450000026

其中，W1为第1个预失真器的预失真参数向量；

Figure BDA0001201715450000027
为第1个预失真器对应的非线性向量的转置；Among them, W 1 is the predistortion parameter vector of the first predistorter;
Figure BDA0001201715450000027
is the transpose of the nonlinear vector corresponding to the first predistorter;

W2为第2个预失真器的预失真参数向量；

Figure BDA0001201715450000028
为第2个预失真器对应的非线性向量的转置；W 2 is the predistortion parameter vector of the second predistorter;
Figure BDA0001201715450000028
is the transpose of the nonlinear vector corresponding to the second predistorter;

WN为第N个预失真器的预失真参数向量；

Figure BDA0001201715450000029
为第N个预失真器对应的非线性向量的转置。W N is the predistortion parameter vector of the Nth predistorter;
Figure BDA0001201715450000029
is the transpose of the nonlinear vector corresponding to the Nth predistorter.

所述的步骤S2包括以下子步骤：The described step S2 includes the following sub-steps:

S21.将各个预失真器得到的预失真信号x1(n),x2(n),...,xN(n)分别送入各自的射频通道；进行数模转换，并上变频至射频频率；S21. Send the predistorted signals x 1 (n), x 2 ( n ), . radio frequency;

S22.将射频通道处理后输出的各个预失真信号通过加法器合成同一路信号

Figure BDA0001201715450000031
S22. Synthesize each predistorted signal output by the radio frequency channel through the adder into the same signal
Figure BDA0001201715450000031

S23.利用功放将信号

Figure BDA0001201715450000032
进行放大后通过天线发射。S23. Use a power amplifier to convert the signal
Figure BDA0001201715450000032
After amplification, it is transmitted through the antenna.

所述的步骤S3中对反馈通道对功放输出的信号

Figure BDA0001201715450000033
进行处理获得数字信号y(n)有如下多种方式：In the described step S3, the feedback channel outputs the signal to the power amplifier
Figure BDA0001201715450000033
There are many ways to process to obtain the digital signal y(n):

第一，将

Figure BDA0001201715450000034
下变频至低频段得到模拟信号y(t)，对模拟信号y(t)直接进行模数转换得到数字信号y(n)；First, will
Figure BDA0001201715450000034
The analog signal y(t) is obtained by down-converting the frequency to the low frequency band, and the analog signal y(t) is directly converted to the digital signal y(n) by analog-digital conversion;

第二，对信号

Figure BDA0001201715450000035
每个频带分别下变频、滤波、模数转换，最后把各个频带的转换得到的数字信号合成一路输出，获得数字信号y(n)；Second, the signal
Figure BDA0001201715450000035
Each frequency band is down-converted, filtered, and analog-to-digital converted, and finally the digital signals obtained by the conversion of each frequency band are synthesized into one output to obtain the digital signal y(n);

第三，将信号

Figure BDA0001201715450000036
进行下变频，下变频过程中，通过频率选择器来选择时钟信号s1(t),s2(t),…,sN(t)中的一个作为变频频率，得到低频信号，进行滤波和模数转换后获得数字信号y(n)。Third, the signal
Figure BDA0001201715450000036
Down-conversion, in the process of down-conversion, the frequency selector is used to select one of the clock signals s 1 (t), s 2 (t),..., s N (t) as the frequency conversion frequency to obtain a low-frequency signal, filter and A digital signal y(n) is obtained after analog-to-digital conversion.

所述的步骤S4包括以下子步骤：The described step S4 includes the following sub-steps:

S41.利用信号x1(n),x2(n),...,xN(n)和y(n)估计原始功放的非线性模型：S41. Use the signals x 1 (n), x 2 (n), . . . , x N (n) and y(n) to estimate the nonlinear model of the original power amplifier:

(1)建立各个频带的非线性功放模型：(1) Establish a nonlinear power amplifier model for each frequency band:

Figure BDA0001201715450000037
Figure BDA0001201715450000037

Figure BDA0001201715450000038
Figure BDA0001201715450000038

……...

Figure BDA0001201715450000039
Figure BDA0001201715450000039

式中，R1,R2,...,RN表示各个频带的功放非线性参数，N表示y(n)中频带个数，频带与数字预失真器个数相同且一一对应；y1(n)表示第1个频带的非线性功放模型的输出信号；y2(n)表示第2个频带的非线性功放模型的输出信号，yN(n)表示第N个频带的非线性功放模型的输出信号；

Figure BDA0001201715450000041
为第1个频带对应的非线性向量的转置；
Figure BDA0001201715450000042
为第2个频带对应的非线性向量的转置；
Figure BDA0001201715450000043
为第N个频带对应的非线性向量的转置；In the formula, R 1 , R 2 ,...,R N represents the nonlinear parameters of the power amplifier in each frequency band, N represents the number of frequency bands in y(n), and the number of frequency bands and digital predistorters are the same and correspond one-to-one; y 1 (n) represents the output signal of the nonlinear power amplifier model of the first frequency band; y 2 (n) represents the output signal of the nonlinear power amplifier model of the second frequency band, y N (n) represents the nonlinearity of the Nth frequency band The output signal of the power amplifier model;
Figure BDA0001201715450000041
is the transpose of the nonlinear vector corresponding to the first frequency band;
Figure BDA0001201715450000042
is the transpose of the nonlinear vector corresponding to the second frequency band;
Figure BDA0001201715450000043
is the transpose of the nonlinear vector corresponding to the Nth frequency band;

(2)由于信号y1(n)、y2(n)和yN(n)均包含在y(n)中，故通过模型辨识的方式中从y(n)中得到功放的非线性模型参数R1,R2,...,RN：(2) Since the signals y 1 (n), y 2 (n) and y N (n) are all included in y(n), the nonlinear model of the power amplifier is obtained from y(n) through model identification Parameters R 1 , R 2 ,...,R N :

将各个频带的非线性功放模型简化为：The nonlinear power amplifier model of each frequency band is simplified as:

Y1＝R1Ψ1；Y 1 =R 1 Ψ 1 ;

Y2＝R2Ψ2；Y 2 =R 2 Ψ 2 ;

............

YN＝RNΨN；Y N =R N Ψ N ;

Y1表示信号y1(n)组成的向量；Y2表示信号y2(n)组成的向量；YN表示信号yN(n)组成的向量，向量长度均为A，Ψ1表示把N组连续时间的向量Φ1(x1,x2,...,xN)排列成非线性矩阵；Ψ2表示把N组连续时间的向量Φ2(x1,x2,...,xN)排列成非线性矩阵；ΨN表示把N组连续时间的向量ΨN(x1,x2,...,xN)排列成非线性矩阵；Y 1 represents the vector composed of the signal y 1 (n); Y 2 represents the vector composed of the signal y 2 (n); Y N represents the vector composed of the signal y N (n), the length of the vector is A, and Ψ 1 represents the N Groups of continuous time vectors Φ 1 (x 1 ,x 2 ,...,x N ) are arranged into nonlinear matrices; Ψ 2 represents the arrangement of N groups of continuous time vectors Φ 2 (x 1 ,x 2 ,..., x N ) is arranged into a nonlinear matrix; Ψ N represents that N groups of continuous time vectors Ψ N (x 1 , x 2 ,...,x N ) are arranged into a nonlinear matrix;

利用LS算法进行参数求解，替换Y1和Y2为Y；其中Y＝[y(1)，y(2),…,y(N)，表示信号y(n)组成的向量；得到参数的估计值为：Use the LS algorithm to solve the parameters, and replace Y 1 and Y 2 with Y; where Y=[y(1), y(2), ..., y(N), which represents the vector composed of the signal y(n); The estimated value is:

Figure BDA0001201715450000044
Figure BDA0001201715450000044

Figure BDA0001201715450000045
Figure BDA0001201715450000045

……...

Figure BDA0001201715450000046
Figure BDA0001201715450000046

Figure BDA0001201715450000047
分别为R1,R2,...,RN的估计值；
Figure BDA0001201715450000047
are the estimated values of R 1 , R 2 ,..., R N respectively;

(3)从非线性参数估计值

Figure BDA0001201715450000048
分别得到每个频带的非线性模型输出的估计值：(3) Estimating values from nonlinear parameters
Figure BDA0001201715450000048
Obtain an estimate of the nonlinear model output for each frequency band separately:

Figure BDA0001201715450000049
Figure BDA0001201715450000049

Figure BDA00012017154500000410
Figure BDA00012017154500000410

……...

Figure BDA0001201715450000051
Figure BDA0001201715450000051

S42.利用信号x1(n),x2(n),...,xN(n)和每个频带的非线性模型输出的估计值

Figure BDA0001201715450000052
提取预失真参数：S42. Utilize the signals x 1 (n), x 2 (n), . . . , x N (n) and the estimated value of the nonlinear model output for each frequency band
Figure BDA0001201715450000052
Extract predistortion parameters:

Figure BDA0001201715450000053
Figure BDA0001201715450000053

Figure BDA0001201715450000054
Figure BDA0001201715450000054

……...

Figure BDA0001201715450000055
Figure BDA0001201715450000055

矩阵E1表示把N组连续时间的向量Φ1(y1,y2,...,yN)排列成的非线性矩阵,Φ1(y1,y2,...,yN)表示对N个信号

Figure BDA0001201715450000056
进行非线性处理得到的非线性向量；矩阵E2表示把N组连续时间的向量Φ2(y1,y2,...,yN)排列成的非线性矩阵，Φ2(y1,y2,...,yN)表示对N个信号
Figure BDA0001201715450000057
进行非线性处理得到的非线性向量；矩阵EN表示把N组连续时间的向量ΦN(y1,y2,...,yN)排列成的非线性矩阵，ΦN(y1,y2,...,yN)表示对N个信号
Figure BDA0001201715450000058
进行非线性处理得到的非线性向量；The matrix E 1 represents a nonlinear matrix that arranges N groups of continuous time vectors Φ 1 (y 1 , y 2 ,...,y N ) into a nonlinear matrix, Φ 1 (y 1 ,y 2 ,...,y N ) represents for N signals
Figure BDA0001201715450000056
The nonlinear vector obtained by nonlinear processing; the matrix E 2 represents the nonlinear matrix that arranges N groups of continuous time vectors Φ 2 (y 1 , y 2 ,..., y N ), Φ 2 (y 1 , y 2 ,...,y N ) means for N signals
Figure BDA0001201715450000057
The nonlinear vector obtained by nonlinear processing; the matrix E N represents the nonlinear matrix that arranges N groups of continuous time vectors Φ N (y 1 , y 2 ,..., y N ), Φ N (y 1 , y 2 ,...,y N ) means for N signals
Figure BDA0001201715450000058
The nonlinear vector obtained by nonlinear processing;

矩阵X1,X2,...,XN分别为：The matrices X 1 , X 2 ,...,X N are respectively:

X1＝[x1(1),x1(2),…x1(n)]；X 1 =[x 1 (1),x 1 (2),...x 1 (n)];

X2＝[x2(1),x2(2),…x2(n)]；X 2 =[x 2 (1),x 2 (2),...x 2 (n)];

……...

XN＝[xN(1),xN(2),…xN(n)]；X N =[x N (1),x N (2),...x N (n)];

S43.将计算得到的预失真向量参数

Figure BDA0001201715450000059
传输给对应频带的数字预失真器对其进行预失真调整，替换原来的预失真参数W1,W2，…，WN。S43. The calculated predistortion vector parameters
Figure BDA0001201715450000059
The digital predistorter transmitted to the corresponding frequency band performs predistortion adjustment, and replaces the original predistortion parameters W 1 , W 2 , . . . , W N .

本发明的有益效果是：本发明能够从功放的输出信号和多带数字预失真模块输出的信号中，提取出包含频带间非线性失真信息在内的非线性预失真参数，对不同频带对应的数字预失真器分别进行调整，进而可以有效抑制近距离多频带功放的非线性是失真。The beneficial effects of the present invention are: the present invention can extract nonlinear pre-distortion parameters including nonlinear distortion information between frequency bands from the output signal of the power amplifier and the signal output by the multi-band digital pre-distortion module. The digital predistorter is adjusted separately, which can effectively suppress the nonlinearity and distortion of the short-range multi-band power amplifier.

附图说明Description of drawings

图1为本发明的系统原理框图；Fig. 1 is the system principle block diagram of the present invention;

图2为本发明的方法流程图；Fig. 2 is the method flow chart of the present invention;

图3为反馈通道第一种信号处理方式的示意图；FIG. 3 is a schematic diagram of the first signal processing mode of the feedback channel;

图4为反馈通道第二种信号处理方式的示意图；Fig. 4 is the schematic diagram of the second signal processing mode of the feedback channel;

图5为反馈通道第三种信号处理方式的示意图。FIG. 5 is a schematic diagram of a third signal processing manner of the feedback channel.

具体实施方式Detailed ways

下面结合附图进一步详细描述本发明的技术方案，但本发明的保护范围不局限于以下所述。The technical solutions of the present invention are further described in detail below with reference to the accompanying drawings, but the protection scope of the present invention is not limited to the following.

如图1所示，一种相邻多频带数字预失真系统，包括多带数字预失真模块、加法器、功放和多带预失真参数计算模块；As shown in Figure 1, an adjacent multi-band digital pre-distortion system includes a multi-band digital pre-distortion module, an adder, a power amplifier and a multi-band pre-distortion parameter calculation module;

所述的多带数字预失真模块包括多个并行运行，且与功放不同频带一一对应数字预失真器(DPD_1～DPD_N)；每个数字预失真器同时处理来自不同信号源的信号，数字预失真器的输出端通过各自的射频通道与加法器连接；加法器的输出端与功放连接，功放的输出端与天线连接；所述功放的输出端还通过反馈通道与多带预失真参数计算模块连接，多带预失真参数计算模块的输出端分别与每一个数字预失真器连接，由多带预失真参数计算模块计算得到预失真参数向量，对各个数字预失真器进行参数调整。The multi-band digital pre-distortion module includes a plurality of digital pre-distorters (DPD_1~DPD_N) that operate in parallel and correspond to different frequency bands of the power amplifier one-to-one; each digital pre-distorter simultaneously processes signals from different signal sources, and the digital pre-distorter The output end of the distorter is connected with the adder through respective radio frequency channels; the output end of the adder is connected with the power amplifier, and the output end of the power amplifier is connected with the antenna; the output end of the power amplifier is also connected with the multi-band predistortion parameter calculation module through the feedback channel The output end of the multi-band pre-distortion parameter calculation module is respectively connected with each digital pre-distorter, the multi-band pre-distortion parameter calculation module calculates the pre-distortion parameter vector, and adjusts the parameters of each digital pre-distorter.

所述的射频通道包括数模转换模块和上变频模块，数模转换模块的输入端与数字预失真器连接，数模转换模块的输出端与上变频模块连接，上变频模块的输出端与加法器连接。The radio frequency channel includes a digital-to-analog conversion module and an up-conversion module, the input end of the digital-to-analog conversion module is connected to the digital predistorter, the output end of the digital-to-analog conversion module is connected to the up-conversion module, and the output end of the up-conversion module is connected to the addition device connection.

所述的反馈通道包括下变频模块和模数转换模块，下变频模块的输入端与功放连接，下变频模块的输出端与模数转换模块连接。The feedback channel includes a down-conversion module and an analog-to-digital conversion module, the input end of the down-conversion module is connected to the power amplifier, and the output end of the down-conversion module is connected to the analog-to-digital conversion module.

所述的反馈通道还包括设置于下变频模块与模数转换模块之间的滤波器。The feedback channel also includes a filter arranged between the down-conversion module and the analog-to-digital conversion module.

所述的多带预失真参数计算模块包括：The multi-band predistortion parameter calculation module includes:

多带非线性模型提取单元，用于根据各个数字预失真器输出的信号和来自反馈通道的反馈信号，提取多带非线性功放模型；The multi-band nonlinear model extraction unit is used to extract the multi-band nonlinear power amplifier model according to the output signal of each digital predistorter and the feedback signal from the feedback channel;

预失真参数提取单元，用于根据多带非线性功放模型和各个数字预失真器输出的信号提取每个数字预失真器的预失真参数向量。The predistortion parameter extraction unit is used for extracting the predistortion parameter vector of each digital predistorter according to the multi-band nonlinear power amplifier model and the signal output by each digital predistorter.

如图2所示，一种相邻多频带数字预失真方法，包括以下步骤：As shown in Figure 2, an adjacent multi-band digital predistortion method includes the following steps:

S1.利用多带数字预失真模块中的每个数字预失真器同时处理来自不同信号源的信号u1(n),u2(n),...,uN(n)，得到多个预失真信号x1(n),x2(n),...,xN(n)，信号源的个数和预失真器的个数相等，均为N，得到的预失真信号x1(n),x2(n),...,xN(n)中包含了功放的非线性失真特性的逆特性，能够降低或抵消功放的非线性失真；S1. Use each digital predistorter in the multi-band digital predistortion module to process signals u 1 (n), u 2 (n), . . . , u N (n) from different signal sources simultaneously to obtain multiple Predistortion signal x 1 (n),x 2 (n),...,x N (n), the number of signal sources is equal to the number of predistorters, both are N, the obtained predistortion signal x 1 (n),x 2 (n),...,x N (n) contains the inverse characteristics of the nonlinear distortion characteristics of the power amplifier, which can reduce or cancel the nonlinear distortion of the power amplifier;

S2.将各个预失真器得到的预失真信号x1(n),x2(n),...,xN(n)分别通过各自的射频通道后合成同一路信号

Figure BDA0001201715450000071
并送入功放进行放大后，得到信号
Figure BDA0001201715450000072
并通过天线进行发射；S2. Synthesize the same signal after passing the predistorted signals x 1 (n), x 2 (n),...,x N (n) obtained by each predistorter through their respective radio frequency channels.
Figure BDA0001201715450000071
And send it to the power amplifier for amplification, get the signal
Figure BDA0001201715450000072
and transmit through the antenna;

S3.采集功放输出的信号

Figure BDA0001201715450000073
通过反馈通道处理后得到数字信号y(n)；S3. Collect the signal output by the power amplifier
Figure BDA0001201715450000073
The digital signal y(n) is obtained after processing through the feedback channel;

S4.利用数字信号y(n)和功率放大器的各路输入信号x1(n),x2(n),...,xN(n)，提取预失真参数向量，对各个数字预失真器进行调整。S4. Using the digital signal y(n) and each input signal x 1 (n), x 2 (n),..., x N (n) of the power amplifier, extract the predistortion parameter vector, and analyze the predistortion parameters for each digital predistortion device to adjust.

所述的步骤S1包括以下子步骤：The described step S1 includes the following sub-steps:

S11.对各个信号源的信号u1(n),u2(n),...,uN(n)，进行非线性处理得到与各个数字预失真器对应的非线性向量；S11. Perform nonlinear processing on the signals u 1 (n), u 2 (n), . . . , u N (n) of each signal source to obtain a nonlinear vector corresponding to each digital predistorter;

S12.将各个数字预失真器的预失真参数向量与对应的非线性向量的转置相乘，得到各个数字预失真器的输出信号：S12. Multiply the predistortion parameter vector of each digital predistorter with the transpose of the corresponding nonlinear vector to obtain the output signal of each digital predistorter:

第1个预失真器的输出信号为：

Figure BDA0001201715450000074
The output signal of the first predistorter is:
Figure BDA0001201715450000074

第2个预失真器的输出信号为：

Figure BDA0001201715450000075
The output signal of the second predistorter is:
Figure BDA0001201715450000075

……...

第N个预失真器的输出信号为：

Figure BDA0001201715450000076
The output signal of the Nth predistorter is:
Figure BDA0001201715450000076

其中，W1为第1个预失真器的预失真参数向量；

Figure BDA0001201715450000077
为第1个预失真器对应的非线性向量的转置；Among them, W 1 is the predistortion parameter vector of the first predistorter;
Figure BDA0001201715450000077
is the transpose of the nonlinear vector corresponding to the first predistorter;

W2为第2个预失真器的预失真参数向量；

Figure BDA0001201715450000078
为第2个预失真器对应的非线性向量的转置；W 2 is the predistortion parameter vector of the second predistorter;
Figure BDA0001201715450000078
is the transpose of the nonlinear vector corresponding to the second predistorter;

WN为第N个预失真器的预失真参数向量；

Figure BDA0001201715450000079
为第N个预失真器对应的非线性向量的转置。W N is the predistortion parameter vector of the Nth predistorter;
Figure BDA0001201715450000079
is the transpose of the nonlinear vector corresponding to the Nth predistorter.

所述的步骤S2包括以下子步骤：The described step S2 includes the following sub-steps:

S21.将各个预失真器得到的预失真信号x1(n),x2(n),...,xN(n)分别送入各自的射频通道；进行数模转换，并上变频至射频频率；S21. Send the predistorted signals x 1 (n), x 2 ( n ), . radio frequency;

S22.将射频通道处理后输出的各个预失真信号通过加法器合成同一路信号

Figure BDA00012017154500000710
S22. Synthesize each predistorted signal output by the radio frequency channel through the adder into the same signal
Figure BDA00012017154500000710

S23.利用功放将信号

Figure BDA00012017154500000711
进行放大后通过天线发射。S23. Use a power amplifier to convert the signal
Figure BDA00012017154500000711
After amplification, it is transmitted through the antenna.

在本申请的实施例中，所述的步骤S3中对反馈通道对功放输出的信号

Figure BDA0001201715450000081
进行处理获得数字信号y(n)有如下多种方式：In the embodiment of the present application, the signal output by the feedback channel to the power amplifier in the step S3
Figure BDA0001201715450000081
There are many ways to process to obtain the digital signal y(n):

第一，如图3所示，将

Figure BDA0001201715450000082
下变频至低频段得到模拟信号y(t)，对模拟信号y(t)直接进行模数转换(ADC)得到数字信号y(n)；此方式需要模数转换速率足够高才能保证数字信号y(n)中包含模拟信号y(t)所有频率信息；First, as shown in Figure 3, the
Figure BDA0001201715450000082
The analog signal y(t) is obtained by down-converting the frequency to the low frequency band, and the analog-to-digital conversion (ADC) is performed directly on the analog signal y(t) to obtain the digital signal y(n); this method requires a high enough analog-to-digital conversion rate to ensure the digital signal y (n) contains all frequency information of the analog signal y(t);

第二，如图4所示，对信号

Figure BDA0001201715450000083
每个频带分别下变频、滤波、模数转换(ADC)，最后把各个频带的转换得到的数字信号合成一路输出，获得数字信号y(n)；Second, as shown in Figure 4, the signal
Figure BDA0001201715450000083
Each frequency band is down-converted, filtered, and analog-to-digital conversion (ADC), and finally the digital signals obtained by the conversion of each frequency band are synthesized into one output to obtain the digital signal y(n);

第三，如图5所示，将信号

Figure BDA0001201715450000084
进行下变频，下变频过程中，通过频率选择器来选择时钟信号s1(t),s2(t),…,sN(t)中的一个作为变频频率，得到低频信号，进行滤波和模数转换(ADC)后获得数字信号y(n)。Third, as shown in Figure 5, the signal
Figure BDA0001201715450000084
Down-conversion, in the process of down-conversion, the frequency selector is used to select one of the clock signals s 1 (t), s 2 (t),..., s N (t) as the frequency conversion frequency to obtain a low-frequency signal, filter and The digital signal y(n) is obtained after analog-to-digital conversion (ADC).

所述的步骤S4包括以下子步骤：The described step S4 includes the following sub-steps:

S41.利用信号x1(n),x2(n),...,xN(n)和y(n)估计原始功放的非线性模型：S41. Use the signals x 1 (n), x 2 (n), . . . , x N (n) and y(n) to estimate the nonlinear model of the original power amplifier:

(1)建立各个频带的非线性功放模型：(1) Establish a nonlinear power amplifier model for each frequency band:

Figure BDA0001201715450000085
Figure BDA0001201715450000085

Figure BDA0001201715450000086
Figure BDA0001201715450000086

……...

Figure BDA0001201715450000087
Figure BDA0001201715450000087

式中，R1,R2,...,RN表示各个频带的功放非线性参数，N表示y(n)中频带个数，频带与数字预失真器个数相同且一一对应；y1(n)表示第1个频带的非线性功放模型的输出信号；y2(n)表示第2个频带的非线性功放模型的输出信号，yN(n)表示第N个频带的非线性功放模型的输出信号；

Figure BDA0001201715450000088
为第1个频带对应的非线性向量的转置；
Figure BDA0001201715450000089
为第2个频带对应的非线性向量的转置；
Figure BDA00012017154500000810
为第N个频带对应的非线性向量的转置；In the formula, R 1 , R 2 ,...,R N represents the nonlinear parameters of the power amplifier in each frequency band, N represents the number of frequency bands in y(n), and the number of frequency bands and digital predistorters are the same and correspond one-to-one; y 1 (n) represents the output signal of the nonlinear power amplifier model of the first frequency band; y 2 (n) represents the output signal of the nonlinear power amplifier model of the second frequency band, y N (n) represents the nonlinearity of the Nth frequency band The output signal of the power amplifier model;
Figure BDA0001201715450000088
is the transpose of the nonlinear vector corresponding to the first frequency band;
Figure BDA0001201715450000089
is the transpose of the nonlinear vector corresponding to the second frequency band;
Figure BDA00012017154500000810
is the transpose of the nonlinear vector corresponding to the Nth frequency band;

(2)由于信号y1(n)、y2(n)和yN(n)均包含在y(n)中，故通过模型辨识的方式中从y(n)中得到功放的非线性模型参数R1,R2,...,RN：(2) Since the signals y 1 (n), y 2 (n) and y N (n) are all included in y(n), the nonlinear model of the power amplifier is obtained from y(n) through model identification Parameters R 1 , R 2 ,...,R N :

将各个频带的非线性功放模型简化为：The nonlinear power amplifier model of each frequency band is simplified as:

Y1＝R1Ψ1；Y 1 =R 1 Ψ 1 ;

Y2＝R2Ψ2；Y 2 =R 2 Ψ 2 ;

............

YN＝RNΨN；Y N =R N Ψ N ;

Y1表示信号y1(n)组成的向量；Y2表示信号y2(n)组成的向量；YN表示信号yN(n)组成的向量，向量长度均为A，Ψ1表示把N组连续时间的向量Φ1(x1,x2,...,xN)排列成非线性矩阵；Ψ2表示把N组连续时间的向量Φ2(x1,x2,...,xN)排列成非线性矩阵；ΨN表示把N组连续时间的向量ΦN(x1,x2,...,xN)排列成非线性矩阵；Y 1 represents the vector composed of the signal y 1 (n); Y 2 represents the vector composed of the signal y 2 (n); Y N represents the vector composed of the signal y N (n), the length of the vector is A, and Ψ 1 represents the N Groups of continuous time vectors Φ 1 (x 1 ,x 2 ,...,x N ) are arranged into nonlinear matrices; Ψ 2 represents the arrangement of N groups of continuous time vectors Φ 2 (x 1 ,x 2 ,..., x N ) is arranged into a nonlinear matrix; Ψ N represents the arrangement of N groups of continuous time vectors Φ N (x 1 , x 2 ,...,x N ) into a nonlinear matrix;

利用LS算法进行参数求解，替换Y1和Y2为Y；其中Y＝[y(1)，y(2),…,y(N)，表示信号y(n)组成的向量；得到参数的估计值为：Use the LS algorithm to solve the parameters, and replace Y 1 and Y 2 with Y; where Y=[y(1), y(2), ..., y(N), which represents the vector composed of the signal y(n); The estimated value is:

Figure BDA0001201715450000091
Figure BDA0001201715450000091

Figure BDA0001201715450000092
Figure BDA0001201715450000092

……...

Figure BDA0001201715450000093
Figure BDA0001201715450000093

Figure BDA0001201715450000094
分别为R1,R2,...,RN的估计值；
Figure BDA0001201715450000094
are the estimated values of R 1 , R 2 ,..., R N respectively;

(3)从非线性参数估计值

Figure BDA0001201715450000095
分别得到每个频带的非线性模型输出的估计值：(3) Estimating values from nonlinear parameters
Figure BDA0001201715450000095
Obtain an estimate of the nonlinear model output for each frequency band separately:

Figure BDA0001201715450000096
Figure BDA0001201715450000096

Figure BDA0001201715450000097
Figure BDA0001201715450000097

……...

Figure BDA0001201715450000098
Figure BDA0001201715450000098

S42.利用信号x1(n),x2(n),...,xN(n)和每个频带的非线性模型输出的估计值

Figure BDA0001201715450000099
提取预失真参数：S42. Utilize the signals x 1 (n), x 2 (n), . . . , x N (n) and the estimated value of the nonlinear model output for each frequency band
Figure BDA0001201715450000099
Extract predistortion parameters:

Figure BDA0001201715450000101
Figure BDA0001201715450000101

Figure BDA0001201715450000102
Figure BDA0001201715450000102

……...

Figure BDA0001201715450000103
Figure BDA0001201715450000103

矩阵E1表示把N组连续时间的向量Φ1(y1,y2,...,yN)排列成的非线性矩阵,1(y1,y2,...,yN)表示对N个信号

Figure BDA0001201715450000104
进行非线性处理得到的非线性向量；矩阵E2表示把N组连续时间的向量Φ2(y1,y2,...,yN)排列成的非线性矩阵，Φ2(y1,y2,...,yN)表示对N个信号
Figure BDA0001201715450000105
进行非线性处理得到的非线性向量；矩阵EN表示把N组连续时间的向量ΦN(y1,y2,...,yN)排列成的非线性矩阵，ΦN(y1,y2,...,yN)表示对N个信号
Figure BDA0001201715450000106
进行非线性处理得到的非线性向量；The matrix E 1 represents a nonlinear matrix that arranges N groups of continuous time vectors Φ 1 (y 1 , y 2 ,...,y N ), and 1 (y 1 ,y 2 ,...,y N ) represents for N signals
Figure BDA0001201715450000104
The nonlinear vector obtained by nonlinear processing; the matrix E 2 represents the nonlinear matrix that arranges N groups of continuous time vectors Φ 2 (y 1 , y 2 ,..., y N ), Φ 2 (y 1 , y 2 ,...,y N ) means for N signals
Figure BDA0001201715450000105
The nonlinear vector obtained by nonlinear processing; the matrix E N represents the nonlinear matrix that arranges N groups of continuous time vectors Φ N (y 1 , y 2 ,..., y N ), Φ N (y 1 , y 2 ,...,y N ) means for N signals
Figure BDA0001201715450000106
The nonlinear vector obtained by nonlinear processing;

矩阵X1,X2,...,XN分别为：The matrices X 1 , X 2 ,...,X N are respectively:

X1＝[x1(1),x1(2),…x1(n)]；X 1 =[x 1 (1),x 1 (2),...x 1 (n)];

X2＝[x2(1),x2(2),…x2(n)]；X 2 =[x 2 (1),x 2 (2),...x 2 (n)];

……...

XN＝[[xN(1),xN(2),…xN(n)]；X N =[[x N (1),x N (2),...x N (n)];

S43.将计算得到的预失真向量参数

Figure BDA0001201715450000107
传输给对应的频带数字预失真器对其进行预失真调整，替换原来的预失真参数W1,W2，…，WN。S43. The calculated predistortion vector parameters
Figure BDA0001201715450000107
It is transmitted to the corresponding frequency band digital predistorter for predistortion adjustment, and the original predistortion parameters W 1 , W 2 , . . . , W N are replaced.

在本申请的一个实施例中，N＝2，步骤S1如下：In an embodiment of the present application, N=2, and step S1 is as follows:

Figure BDA0001201715450000108
Figure BDA0001201715450000108

Figure BDA0001201715450000109
表示对2个信号源u1(n),u2(n)进行预失真非线性处理得到的非线性向量，该向量中所有元素的中心频率与信号源u1(n)的中心频率相同，其中向量
Figure BDA00012017154500001010
的第k*j*L+l个的元素的一种构成方式为：
Figure BDA0001201715450000109
represents the nonlinear vector obtained by performing predistortion nonlinear processing on two signal sources u 1 (n), u 2 (n), the center frequency of all elements in the vector is the same as the center frequency of the signal source u 1 (n), where the vector
Figure BDA00012017154500001010
One way to form the k*j*L+lth element of is:

Figure BDA0001201715450000111
Figure BDA0001201715450000111

Figure BDA0001201715450000112
为预失真参数向量，向量长度与
Figure BDA0001201715450000113
相同；
Figure BDA0001201715450000112
is the predistortion parameter vector, and the vector length is the same as
Figure BDA0001201715450000113
same;

Figure BDA0001201715450000114
(i>1,i为奇数)表示对2个信号源u1(n),u2(n)进行预失真非线性处理得到的非线性向量，该向量中所有元素的信号中心频率与信号源u1(n),u2(n)的i阶交调分量
Figure BDA0001201715450000115
的中心频率相同，其中向量
Figure BDA0001201715450000116
的第k*j*L+l个的元素的一种构成方式为：
Figure BDA0001201715450000114
(i>1, i is an odd number) represents a nonlinear vector obtained by performing predistortion nonlinear processing on two signal sources u 1 (n), u 2 (n), and the signal center frequency of all elements in the vector is the same as the signal source i-order intermodulation components of u 1 (n), u 2 (n)
Figure BDA0001201715450000115
the center frequencies of the same, where the vector
Figure BDA0001201715450000116
One way to form the k*j*L+lth element of is:

Figure BDA0001201715450000117
Figure BDA0001201715450000117

Figure BDA0001201715450000118
为预失真参数向量，向量长度与
Figure BDA0001201715450000119
相同；
Figure BDA0001201715450000118
is the predistortion parameter vector, and the vector length is the same as
Figure BDA0001201715450000119
same;

当把所有的向量

Figure BDA00012017154500001110
依次排列成一个向量
Figure BDA00012017154500001111
把所有非线性向量一次排列成一个向量
Figure BDA00012017154500001112
When putting all the vectors
Figure BDA00012017154500001110
arranged in sequence into a vector
Figure BDA00012017154500001111
Arrange all nonlinear vectors into one vector at a time
Figure BDA00012017154500001112

第一个数字预失真器的输出可以写成：The output of the first digital predistorter can be written as:

Figure BDA00012017154500001113
Figure BDA00012017154500001113

其中T表示矩阵转置操作。where T represents the matrix transpose operation.

同理，第二个数字预失真器的输出可以写成：Similarly, the output of the second digital predistorter can be written as:

Figure BDA00012017154500001114
Figure BDA00012017154500001114

其中，Φ2(u1,u2)的构成与Φ1(u1,u2)相似；只是在构成具体向量

Figure BDA00012017154500001115
时，交换u1(n)和u2(n)的位置。Among them, the composition of Φ 2 (u 1 , u 2 ) is similar to that of Φ 1 (u 1 , u 2 );
Figure BDA00012017154500001115
, swap the positions of u 1 (n) and u 2 (n).

在N＝2的实施例中，步骤S4具体如下：In the embodiment of N=2, step S4 is specifically as follows:

首先建立2个频带的非线性功放模型如下：Firstly, the nonlinear power amplifier model of 2 frequency bands is established as follows:

Figure BDA00012017154500001116
Figure BDA00012017154500001116

其中，y1(n)和y2(n)分别是第一频带和第二频带功放模型输出；Φ1(x1,x2)表示对2个信号x1(n),x2(n)进行非线性处理得到的非线性向量；其内部构成与Φ1(u1,u2)相似，只是分别替换信号u1(n),u2(n)为x1(n),x2(n)；Φ2(x1,x2)表示对2个信号x1(n),x2(n)进行非线性处理得到的非线性向量；其内部构成与Φ2(u1,u2)相似，只是分别替换信号u1(n),u2(n)为x1(n),x2(n)；Among them, y 1 ( n ) and y 2 ( n ) are the output of the power amplifier model in the first frequency band and the second frequency band respectively ; ) is a nonlinear vector obtained by nonlinear processing; its internal composition is similar to Φ 1 (u 1 , u 2 ), except that the signals u 1 (n), u 2 (n) are replaced by x 1 (n), x 2 (n); Φ 2 (x 1 , x 2 ) represents a nonlinear vector obtained by nonlinear processing of two signals x 1 (n), x 2 (n); its internal composition is the same as that of Φ 2 (u 1 , u 2 ) Similar, just replace the signals u 1 (n), u 2 (n) with x 1 (n), x 2 (n) respectively;

由于信号y1(n)和y2(n)均包含y(n)中，通过模型辨识的方式可以从y(n)中分别得到功放的非线性模型参数R1和R2。具体辨识方法可以是最小二乘算法(Least Square:LS)或者递归最小二乘算法RLS。以LS算法为例：Since the signals y 1 (n) and y 2 (n) are both included in y(n), the nonlinear model parameters R1 and R2 of the power amplifier can be obtained from y(n) by means of model identification. The specific identification method may be the least squares algorithm (Least Square: LS) or the recursive least squares algorithm RLS. Take the LS algorithm as an example:

上式写成矩阵形式为：The above formula is written in matrix form as:

Figure BDA0001201715450000121
Figure BDA0001201715450000121

其中Y1和Y2分别表示信号y1(n)和y2(n)组成的向量，向量长度为N；R1和R2分别表示频带1和频带2对应的非线性参数向量，其构成方式与W1和W2类似；Ψ1表示把N组连续时间的向量Φ1(x1,x2)排列成非线性矩阵；Ψ2表示把N组连续时间的向量Φ2(x1,x2)排列成非线性矩阵；Among them, Y 1 and Y 2 represent the vectors composed of signals y 1 (n) and y 2 (n), respectively, and the vector length is N; R1 and R2 represent the nonlinear parameter vectors corresponding to frequency band 1 and frequency band 2, respectively. W1 is similar to W2; Ψ 1 represents the arrangement of N groups of continuous time vectors Φ 1 (x 1 , x 2 ) into a nonlinear matrix; Ψ 2 represents the arrangement of N groups of continuous time vectors Φ 2 (x 1 , x 2 ) into a nonlinear matrix;

用LS算法进行参数求解，并且替换Y1和Y2为Y,得到参数的估计值为：Use the LS algorithm to solve the parameter, and replace Y 1 and Y 2 with Y, and the estimated value of the parameter is:

Figure BDA0001201715450000122
Figure BDA0001201715450000122

Figure BDA0001201715450000123
和
Figure BDA0001201715450000124
分别为R1和R2的估计值。
Figure BDA0001201715450000123
and
Figure BDA0001201715450000124
are the estimated values of R1 and R2, respectively.

从非线性参数估计值

Figure BDA0001201715450000125
和
Figure BDA0001201715450000126
分别得到每个频带的非线性模型输出的估计值：Estimating values from nonlinear parameters
Figure BDA0001201715450000125
and
Figure BDA0001201715450000126
Obtain an estimate of the nonlinear model output for each frequency band separately:

Figure BDA0001201715450000127
Figure BDA0001201715450000127

进而：and then:

Figure BDA0001201715450000128
Figure BDA0001201715450000128

Figure BDA0001201715450000129
Figure BDA0001201715450000129

预失真参数提取：利用x1(n),x2(n)和功放模型估计模块的输出

Figure BDA00012017154500001210
和
Figure BDA00012017154500001211
来提取预失真参数，其中一种提取方法如下：Predistortion parameter extraction: use x 1 (n), x 2 (n) and the power amplifier model to estimate the output of the module
Figure BDA00012017154500001210
and
Figure BDA00012017154500001211
to extract the predistortion parameters, one of the extraction methods is as follows:

其中一种计算方法可以利用传统的间接学习结构来得到W：One of the computational methods can utilize the traditional indirect learning structure to obtain W:

Figure BDA00012017154500001212
Figure BDA00012017154500001212

Figure BDA00012017154500001213
Figure BDA00012017154500001213

其中矩阵E1表示把N组连续时间的向量Φ1(y1,y2)排列成非线性矩阵；E2表示把N组连续时间的向量Φ2(y1,y2)排列成非线性矩阵；Φ1(y1,y2)表示对2个信号

Figure BDA00012017154500001214
和
Figure BDA00012017154500001215
进行非线性处理得到的非线性向量；其内部构成与Φ1(u1,u2)相似，只是分别替换信号u1(n)和u2(n)为
Figure BDA0001201715450000136
和
Figure BDA0001201715450000131
2(y1,y2)表示对2个信号
Figure BDA0001201715450000132
和
Figure BDA0001201715450000133
进行非线性处理得到的非线性向量；其内部构成与Φ2(u1,u2)相似，只是分别替换信号u1(n)和u2(n)为
Figure BDA0001201715450000137
和
Figure BDA0001201715450000138
The matrix E 1 represents the arrangement of N groups of continuous time vectors Φ 1 (y 1 , y 2 ) into a nonlinear matrix; E 2 represents the arrangement of N groups of continuous time vectors Φ 2 (y 1 , y 2 ) into nonlinear matrices matrix; Φ 1 (y 1 , y 2 ) represents the pair of 2 signals
Figure BDA00012017154500001214
and
Figure BDA00012017154500001215
The nonlinear vector obtained by nonlinear processing; its internal structure is similar to Φ 1 (u 1 , u 2 ), except that the signals u 1 (n) and u 2 (n) are replaced by
Figure BDA0001201715450000136
and
Figure BDA0001201715450000131
2 (y 1 , y 2 ) means for 2 signals
Figure BDA0001201715450000132
and
Figure BDA0001201715450000133
The nonlinear vector obtained by nonlinear processing; its internal structure is similar to Φ 2 (u 1 , u 2 ), except that the signals u 1 (n) and u 2 (n) are replaced by
Figure BDA0001201715450000137
and
Figure BDA0001201715450000138

并且：and:

Figure BDA0001201715450000134
Figure BDA0001201715450000134

根据估计得到的

Figure BDA0001201715450000135
传输给对应频带的数字预失真器对其进行预失真调整，替换原来的预失真参数W1,W2。according to the estimated
Figure BDA0001201715450000135
The digital predistorter transmitted to the corresponding frequency band performs predistortion adjustment, and replaces the original predistortion parameters W 1 , W 2 .

Claims (6)

1. A contiguous multi-band digital predistortion system, characterized by: the system comprises a multi-band digital predistortion module, an adder, a power amplifier and a multi-band predistortion parameter calculation module;
the multi-band digital predistortion module comprises a plurality of digital predistorters which run in parallel and correspond to different frequency bands of the power amplifier one by one; each digital predistorter processes signals from different signal sources at the same time, and the output ends of the digital predistorters are connected with the adder through respective radio frequency channels; the output end of the adder is connected with a power amplifier, and the output end of the power amplifier is connected with an antenna; the output end of the power amplifier is also connected with a multi-band predistortion parameter calculation module through a feedback channel, the output end of the multi-band predistortion parameter calculation module is respectively connected with each digital predistorter, a predistortion parameter vector is calculated by the multi-band predistortion parameter calculation module, and parameter adjustment is carried out on each digital predistorter;
a method of adjacent multi-band digital predistortion for an adjacent multi-band digital predistortion system, comprising the steps of:
s1, simultaneously processing signals u from different signal sources by using each digital predistorter in a multi-band digital predistortion module1(n)，u2(n)，...，uN(n) obtaining a plurality of pre-distorted signals x1(n)，x2(n)，...，xN(N), the number of signal sources is equal to the number of predistorters, and the number of signal sources is N, so that a predistortion signal x is obtained1(n)，x2(n)，....xN(n) the inverse characteristic of the nonlinear distortion characteristic of the power amplifier is included, so that the nonlinear distortion of the power amplifier can be reduced or counteracted;
s2, pre-distortion signals x obtained by each pre-distorter1(n)，x2(n)，...，xN(n) respectively passing through respective radio frequency channels to synthesize the same path of signal
Figure FDA0002575890670000011
And sending the signal to a power amplifier for amplification to obtain a signal
Figure FDA0002575890670000012
And transmitting through an antenna;
s3, collecting signals output by the power amplifier
Figure FDA0002575890670000013
Obtaining a digital signal y (n) after being processed by a feedback channel
S4, utilizing digital signal y (n) and each input signal x of power amplifier1(n)，x2(n)，...，xN(n), extracting a predistortion parameter vector, and adjusting each digital predistorter;
the step S1 includes the following sub-steps:
s11, signals u of each signal source1(n)，u2(n)，...，uN(n), carrying out nonlinear processing to obtain nonlinear vectors corresponding to the digital predistorters;
s12, multiplying the predistortion parameter vector of each digital predistorter with the transpose of the corresponding nonlinear vector to obtain an output signal of each digital predistorter:
the output signal of the 1 st predistorter is
Figure FDA0002575890670000014
The output signal of the 2 nd predistorter is
Figure FDA0002575890670000015
……
The output signal of the Nth predistorter is
Figure FDA0002575890670000016
Wherein, W1 is a predistortion parameter vector of the 1 st predistorter;
Figure FDA0002575890670000017
transpose of the nonlinear vector corresponding to the 1 st predistorter;
w2 is the predistortion parameter vector of the 2 nd predistorter;
Figure FDA0002575890670000021
transpose of the nonlinear vector corresponding to the 2 nd predistorter;
WN is a predistortion parameter vector of the Nth predistorter;
Figure FDA0002575890670000022
transpose the nonlinear vector corresponding to the nth predistorter;
the signal output to the power amplifier by the feedback channel in the step S3
Figure FDA0002575890670000023
The processing is performed to obtain the digital signal y (n) in the following ways:
first, the
Figure FDA0002575890670000024
Performing down-conversion to a low-frequency band to obtain an analog signal y (t), and directly performing analog-to-digital conversion on the analog signal y (t) to obtain a digital signal y (n);
second, to the signal
Figure FDA0002575890670000025
Each frequency band is subjected to down-conversion, filtering and analog-to-digital conversion respectively, and finally digital signals obtained by conversion of each frequency band are synthesized into one path to be output to obtain digital signals y (n);
thirdly, the signals are transmitted
Figure FDA0002575890670000026
Performing down-conversion by selecting the clock signal s via the frequency selector1(t)，s2(t)，…，sNOne of (t) is used as a frequency conversion frequency to obtain a low-frequency signal, and a digital signal y (n) is obtained after filtering and analog-to-digital conversion; the step S4 includes the following sub-steps:
s41, utilizing the signal x1(n)，x2(n)，...，xN(n) and y (n) estimating a nonlinear model of the original power amplifier:
(1) establishing a nonlinear power amplifier model of each frequency band:
Figure FDA0002575890670000027
Figure FDA0002575890670000028
……
Figure FDA0002575890670000029
in the formula, R1，R2，...，RNThe power amplifier nonlinear parameters of each frequency band are represented, N represents the number of y (N) intermediate frequency bands, and the number of the frequency bands is the same as that of the digital predistorters and corresponds to that of the digital predistorters one by one; y is1(n) output of the 1 st band nonlinear power amplifier modelA signal; y is2(n) represents the output signal of the nonlinear power amplifier model of the 2 nd frequency band, yN(N) an output signal of the nonlinear power amplifier model representing the nth frequency band;
Figure FDA00025758906700000210
transpose of the nonlinear vector corresponding to the 1 st frequency band;
Figure FDA00025758906700000211
transpose of the nonlinear vector corresponding to the 2 nd frequency band;
Figure FDA00025758906700000212
transpose of the nonlinear vector corresponding to the nth frequency band;
(2) due to the signal y1(n)、y2(n) and yN(n) are all included in y (n), so that the nonlinear model parameter R of the power amplifier is obtained from y (n) in a model identification mode1，R2，...，RN：
Simplifying the nonlinear power amplifier model of each frequency band into:
Y1＝R1Ψ1；
Y2＝R2Ψ2；
……
YN＝RNΨN；
y1 denotes the signal Y1(n) a vector of components; y2 denotes the signal Y2(n) a vector of components; YN represents signal yN(N) are all A, psi 1 represents N groups of continuous time vectors phi 1 (x)1，x2，...，xN) Arranged in a non-linear matrix; Ψ 2 represents a vector Φ 2 (x) that divides N sets of consecutive times1，x2，...，xN) Arranged in a non-linear matrix; Ψ N represents a vector Φ N (x) that represents N groups of consecutive times1，x2，...，xN) Arranged in a non-linear matrix;
carrying out parameter solution by using an LS algorithm, and replacing Y1 and Y2 with Y; where Y ═ Y (1), Y (2), …, Y (n) ], represents a vector of signals Y (n); the estimated values of the parameters were obtained as:
Figure FDA0002575890670000031
Figure FDA0002575890670000032
Figure FDA0002575890670000033
Figure FDA0002575890670000034
are each R1，R2，...，RNAn estimated value of (d);
(3) from non-linear parameter estimates
Figure FDA0002575890670000035
Respectively obtaining an estimated value of the nonlinear model output of each frequency band:
Figure FDA0002575890670000036
Figure FDA0002575890670000037
Figure FDA0002575890670000038
s42, utilizing the signal x1(n)，x2(n)，...，xN(n) and an estimate of the nonlinear model output for each frequency band
Figure FDA0002575890670000039
Extracting predistortion parameters:
Figure FDA00025758906700000310
Figure FDA00025758906700000311
……
Figure FDA00025758906700000312
the matrix E1 represents a vector Φ 1 (y) of N sets of consecutive times1，y2，...，yN) Arranged in a non-linear matrix, Φ 1 (y)1y2，...，yN) Representing the N signals
Figure FDA00025758906700000313
Carrying out nonlinear processing to obtain a nonlinear vector; the matrix E2 represents a vector Φ 2 (y) of N sets of consecutive times1，y2，...，yN) Arranged in a non-linear matrix, Φ 2 (y)1，y2，...，yN) Representing the N signals
Figure FDA0002575890670000041
Carrying out nonlinear processing to obtain a nonlinear vector; the matrix EN represents a vector of N successive time groups φ N (y)1，y2，...，yN) Arranged in a non-linear matrix, Φ N (y)1，y2，...，yN) Representing the N signals
Figure FDA0002575890670000042
Carrying out nonlinear processing to obtain a nonlinear vector;
matrix X1，X2，...，XNRespectively as follows:
X1＝[x1(1)，x1(2)，…x1(n)]；
X2＝[x2(1)，x2(2)，…x2(n)]；
……
XN＝[xN(1)，xN(2)，…xN(n)]；
s43, pre-distortion vector parameters obtained through calculation
Figure FDA0002575890670000043
The digital predistorter transmitted to the corresponding frequency band carries out predistortion adjustment on the frequency band to replace the original predistortion parameter W1，W2，…，WN。
2. The adjacent multiband digital predistortion system of claim 1, wherein the radio frequency channel comprises a digital-to-analog conversion module and an up-conversion module, an input end of the digital-to-analog conversion module is connected with the digital predistorter, an output end of the digital-to-analog conversion module is connected with the up-conversion module, and an output end of the up-conversion module is connected with the adder.
3. The adjacent multiband digital predistortion system of claim 1, wherein the feedback channel comprises a down-conversion module and an analog-to-digital conversion module, an input end of the down-conversion module is connected with the power amplifier, and an output end of the down-conversion module is connected with the analog-to-digital conversion module.
4. A contiguous multiband digital predistortion system according to claim 1 or 3, wherein the feedback path further comprises a filter disposed between the down-conversion module and the analog-to-digital conversion module.
5. The system of claim 1, wherein the multi-band predistortion parameter calculation module comprises:
the multi-band nonlinear model extraction unit is used for extracting a multi-band nonlinear power amplifier model according to the signals output by each digital predistorter and the feedback signals from the feedback channels;
and the predistortion parameter extraction unit is used for extracting the predistortion parameter vector of each digital predistorter according to the multi-band nonlinear power amplifier model and the signals output by each digital predistorter.
6. The adjacent multiband digital predistortion system of claim 1, wherein the step S2 includes the sub-steps of:
s21, pre-distortion signals x obtained by each pre-distorter1(n)，x2(n)，...，xN(n) sending the signals into respective radio frequency channels; performing digital-to-analog conversion and up-converting to radio frequency;
s22, synthesizing all pre-distortion signals output after radio frequency channel processing into the same path of signal through an adder
Figure FDA0002575890670000044
And S23, amplifying the signals by using a power amplifier and then transmitting the signals through an antenna.
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