Digital predistortion module for solid state power amplifier OFDM signal in onboard data link and realization method

Abstract

The invention discloses a digital predistortion module for solid state power amplifier OFDM signals in an onboard data link. The predistortion module comprises an iterative clipping and filtering unit, a raised cosine filtering unit and an oversampling predistortion unit. The iterative clipping and filtering unit is used for reducing the peak-to-average ratio of the signals. The raised cosine filtering unit is used for reducing signal spectrum out-band interference. The oversampling predistortion unit is used for carrying out nonlinear processing on oversampling signal amplitude in received signals, obtaining predistortion processing OFDM signals and outputting the predistorted OFDM signals. The invention also discloses a realization method for the predistortion module. Through applicationof the module and the realization method, the peak-to-average ratio of the signals can be reduced, signal in-band and out-band comprehensive optimization is realized, and design complexity and realization cost of a transmitter are not increased.

Description

technical field [0001] The invention relates to the technical field of digital wireless communication transmission, in particular to a solid-state power amplifier OFDM signal digital pre-distortion module in an airborne data link and an implementation method. Background technique [0002] In the UAV data link system, the airborne data link terminal needs to transmit high-speed image data to the ground station terminal, and the airborne terminal often uses a power amplifier with several watts of output. This type of amplifier is generally a solid-state power amplifier, which generally has better linearity. However, poor nonlinear characteristics still exist near the saturation point of solid-state power amplifiers. Orthogonal Frequency Division Multiplexing (OFDM) technology can realize high-speed and reliable data transmission in a low-elevation environment, but its high peak-to-average ratio also poses more severe challenges to airborne power amplifiers with more restricti...

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Problems solved by technology

However, the implementation of this kind of algorithm needs to add a hardware channel, which greatly affects the instability of the system and the implementation cost.

[0005] With the high-speed data transmission code rate of UAV airborne data link increasing by orders of magnitude, OFDM signal shows the advantages of high-speed and reliable data transmission in low elevation angle environment, but its high peak-to-average ratio characteristic poses a great challenge to the airborne solid-state power amplifier

On the one hand, the method in the above literature only considers reducing the peak-to-average ratio of the signal, and cannot realize the comprehensive optimization of the signal in-band and out-of-band; on the other hand, the designed feedback pre-distortion method increases the design complexity and implementation cost of the transmitter

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