Digital predistortion system for inhibiting noise of feedback signal
A technology of digital predistortion and predistorter, applied in the field of linearization system
Inactive Publication Date: 2011-05-11
XIDIAN UNIV
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[0003] The purpose of the present invention is to solve the anti-noise problem of pre-distortion processing of power amplifiers in broadband wireless communication systems. Aiming at broadband strong memory nonlinear power amplifiers, a digital pre-distortion system and method for suppressing feedback signal noise are proposed to meet the requirements of broadband wireless communication systems. Transmitter Linearization Requirements
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[0050] Embodiments of the present invention will be described in detail below with reference to the accompanying drawings. This embodiment is implemented on the premise of the technical solution of the present invention, and the detailed implementation and specific operation process are given, but the protection scope of the present invention is not limited to the following embodiments.
[0051] Refer to attached figure 1 , The digital predistortion system of the present invention includes: a predistorter, an amplifier, a nonlinear filter, a first adder, a second adder, an improved NLMS module and a total of 7 basic units of the NLMS module. The input baseband signal x(n) first enters the predistorter for inverse processing of the nonlinear characteristics of the amplifier, and outputs two identical signals z(n) to the amplifier and the nonlinear filter respectively; ) signal is subjected to power amplification processing, and its output signal y(n) is transmitted to the seco...
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The invention discloses a digital predistortion system and a digital predistortion method for inhibiting noise of a feedback signal. By the system and the method, the noise-resistant problem of predistortion processing of a strong memory nonlinear amplifier is mainly solved. The system comprises a predistorter, an amplifier, a nonlinear filter, a first summator, a second summator, an improved normalized least mean square (NLMS) module and an NLMS basic module, wherein the predistorter performs nonlinear inverse processing on base band input and then outputs the base band to the amplifier and the nonlinear filter; the amplifier performs power amplification on the input signal and then outputs the signal to the second summator; the nonlinear filter performs noise filtering processing on theinput signal and outputs the signal to the first summator and the second summator; the first summator calculates predistortion error; the second summator calculates feedback error; the improved NLMS module iteratively updates a nonlinear filter coefficient; and the NLMS module iteratively updates a predistorter coefficient. By the system and the method, the influence of feedback noise on the properties of a wideband predistortion method can be obviously improved. The system and the method can be applied to linearized systems of various wideband wireless communication transmitters.
Description
technical field [0001] The invention belongs to the field of wireless communication, and relates to a digital predistortion system and method for suppressing feedback signal noise, which can be used in linearization systems of various broadband wireless communication transmitters. Background technique [0002] At present, baseband digital predistortion has become the mainstream technology for the linearization of RF power amplifiers in wireless communication systems. However, the existing digital pre-distortion processing method is very sensitive to the signal noise component included in the feedback signal, resulting in poor spectrum improvement performance and stability of the pre-distortion. In terms of predistortion processing methods for suppressing feedback noise, Po-Chun Chien gave a predistortion method based on direct learning and indirect learning structures in "Performance Analysis of Polynomial Predistorter Based on Indirect and Direct Learning Architecture"; Zho...
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Inventor 王勇李仁鹏葛建华宫丰奎李靖张南高明
Owner XIDIAN UNIV