Improved RASCAL algorithm digital pre-distortion design method and system and application

Abstract

The invention belongs to the technical field of satellite communication, and discloses an improved RASCAL algorithm digital pre-distortion design method and system and application, the improved RASCAL algorithm digital pre-distortion design method comprises the steps that TWTA characteristics are divided into linear segmentation and non-linear segmentation, the linear segmentation part only places derivative values of a linear function of a partition in a partition range, and the nonlinear segmentation part is used for placing derivative coefficient values of a quadratic term and a linear term of a quadratic function; when non-linear amplification or pre-distortion needs to be executed, an appropriate derivative coefficient is selected according to the amplitude value of a current transmission signal to be multiplied by a monomial term or a quadratic term of a corresponding interval, so that the execution modes of the output amplitude and the output phase of the non-linear model are similar, and the difference is that the output phase needs to be added with the calculated phase offset. According to the invention, the non-memory nonlinear distortion in satellite communication can be effectively pre-compensated, the output signal is more accurate, and the occupancy rate of hardware LUT resources is reduced.

Description

technical field [0001] The invention belongs to the technical field of satellite communication, and in particular relates to an improved RASCAL algorithm digital predistortion design method, system and application. Background technique [0002] At present, high throughput communication satellites (HTS, High Throughput Satellite), also known as high throughput communication satellites, have a communication capacity several times or even dozens of times higher than conventional communication satellites under the condition of using the same frequency resources, and the transmission bandwidth is large. [0003] On the satellite transponder, the signal passes through the IMUX filter, then amplified by the TWTA, and finally passed through the OMUX filter to ensure spectral integrity during user link transmission. IMUX and OMUX filters have imperfect frequency responses and introduce linear distortion in the form of Intersymbol Interference (ISI), while TWTA introduces nonlinear di...

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Problems solved by technology

[0007] (1) The frequency response of IMUX and OMUX filters is not perfect, which will introduce linear distortion in the form of intersymbol interference, while TWTA introduces nonlinear distortion

[0008] (2) In the existing memoryless nonlinear HPA predistortion method, since the division is stored in the FPGA in the form of points, the complexity of hardware implementation and resource occupancy are relatively high

[0009] The difficulty in solving the above problems and defects is: the TWTA in the satellite communication scenario is a spaceborne device, and most ground nonlinear algorithms can be completed through an adaptive compensation structure, but the satellite communication scenario cannot be self-adaptive, so it is necessary to adjust the TWTA in advance Analyze the characteristics, and do pre-distortion processing in the transmitter to complete nonlinear pre-compensation

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