A Crest Factor Reduction Technique for LTE Signals with Target Relaxation in Power Amplifier Linearization

Abstract

The signal conditioning treatment to achieve good relation of power with radio-frequency (RF) conversion in conventional transceiver systems require precise baseband models. A developed framework is built to provide a demonstration of the modeling figures of merit with orthogonal frequency division multiplexing (OFDM) support under signal conditioning and transmission restrictions to waveforms with high peak to average power ratio (PAPR) in practical applications. Therefore, peak and average power levels have to be limited to correct high PAPR for a better suited correction power from the amplifier that can lead to compression or clipping in the signal of interest. This work presents an alternative joint crest factor reduction (CFR) algorithm to correct the performance of PAPR. A real-time field-programmable gate array (FPGA) testbed is developed to characterize and measure the behavior of an amplifier using a single-carrier 64–QAM OFDM based on long-term evolution (LTE) downlink at 2.40 GHz as stimulus, across wide modulation bandwidths. The results demonstrate that the CFR accuracy capabilities for the signal conditioning show a reliable clipping reduction to give a smooth version of the clipping signal and provide a factor of correction for the unwanted out-of-band emission validated according to the adjacent channel power ratio (ACPR), PAPR, peak power, complementary cumulative distribution function (CCDF), and error vector magnitude (EVM) figures of merit.

A Comparison of Surrogate Behavioral Models for Power Amplifier Linearization under High Sparse Data

“…Previous to this step, the setup system is adequately calibrated so that a synchronized signal is applied properly to the PA input. Please note that we set a calibration power for power peak and average levels at the PA output after each iteration to ensure adequate CFR amplitude levels in the overall system [ 1 ]. Figure 9 (1) (2) shows the transceiver set at GHz center frequency using the ARRadio card integrates an AD9361 RF transceiver.…”

“…In addition, Radio-frequency/Microwave transmission circuits with wide dynamic bandwidths represent a challenge for modeling and DPD linearization techniques. Behavioral modeling based on higher-order polynomial systems for long-term and short-term induced memory represents an efficient methodology for improving spectral efficiency [ 1 , 2 ]. The selection of the primary method for the modeling and linearization stages is essential if it is required to use multivariable data, gain precision, and not increase the involved coefficients during hardware implementation [ 3 ].…”