A Crest Factor Reduction Technique for LTE Signals with Target Relaxation in Power Amplifier Linearization
José Ricardo Cárdenas-Valdez1, Jose Alejandro Galaviz-Aguilar2, Cesar Vargas-Rosales2
1IT de Tijuana, Tecnológico Nacional de México, Tijuana 22435, Mexico.
Sensors (Basel, Switzerland)
|February 15, 2022
Summary
This study introduces a novel crest factor reduction (CFR) algorithm to improve radio-frequency (RF) power amplifier performance by mitigating high peak-to-average power ratio (PAPR) issues in orthogonal frequency division multiplexing (OFDM) systems.
Area of Science:
- Electrical Engineering
- Signal Processing
- Wireless Communications
Background:
- Precise baseband models are crucial for effective signal conditioning in radio-frequency (RF) transceiver systems.
- High peak-to-average power ratio (PAPR) in orthogonal frequency division multiplexing (OFDM) waveforms poses challenges for amplifiers, leading to clipping and distortion.
- Existing methods require careful power limitation, impacting amplifier efficiency and signal integrity.
Purpose of the Study:
- To develop and demonstrate a framework for modeling signal conditioning performance with support for OFDM waveforms.
- To introduce an alternative joint crest factor reduction (CFR) algorithm for mitigating high PAPR.
- To validate the effectiveness of the CFR algorithm in practical applications and characterize amplifier behavior.
Main Methods:
- A real-time field-programmable gate array (FPGA) testbed was developed for characterization and measurement.
- A single-carrier 64-QAM OFDM signal based on LTE downlink at 2.40 GHz was used as the stimulus.
- The joint CFR algorithm was applied to correct high PAPR and its impact on amplifier performance was analyzed.
Main Results:
- The developed CFR algorithm demonstrated reliable clipping reduction, producing a smoother signal.
- The algorithm effectively corrected unwanted out-of-band emissions, validated by adjacent channel power ratio (ACPR) measurements.
- Key performance metrics including PAPR, peak power, complementary cumulative distribution function (CCDF), and error vector magnitude (EVM) were analyzed.
Conclusions:
- The joint CFR algorithm offers an effective solution for improving signal conditioning and amplifier performance in OFDM systems.
- The developed FPGA testbed provides a valuable tool for characterizing and measuring RF amplifier behavior under signal conditioning restrictions.
- The findings contribute to more efficient and reliable wireless communication systems by addressing PAPR challenges.
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