High Precision Adaptive Calibration Feedback in RF Front-end for Digital Pre-distortion Application

Emre Ulusoy*, Bahadir Ozkan*, Furkan Barin*, Fatih Maden*, Ercem Yesil, Dursun Baran*, Adem Eren*, Tufan Coskun Karalar, Ahmet Tekin, Ertan Zencir*

*Corresponding author for this work

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review


This paper introduces an adaptive feedback calibration circuit designed for use in V2X (Vehicle-to-Everything) systems operating at 5.9 GHz within 5G NR systems. The adaptive loop comprises the observation receiver, functioning in the n47 frequency band (5855-5925 MHz), and the digital pre-distorter, both situated on the same die as the RF Power Amplifier. The TX signal, featuring a bandwidth of up to 40 MHz and a PAPR of 8 to 10 dB, undergoes digitization by a receiver with a notably high bandwidth, such as 120 MHz. Subsequently, the digitized signal is input into the digital pre-distortion circuit with a 10-bit high precision. Circuit characteristics obtained from post-layout simulations, as of the publication date, have been incorporated into a comprehensive model. Simulations assessing EVM and ACLR of the TX signal at the Front-end module output have been executed. The EVM value enhances from 5.2% RMS when the adaptive DPD is deactivated to 1.5% RMS when activated. Moreover, the ACLR decreases from -30 dBc to better than -40 dBc. The observation receiver of the calibration feedback system, designed using 130-nm SOI CMOS technology, possesses dimensions of 1750 µm × 3200 µm. The DPD circuit, situated on a separate die but utilizing the same process, features dimensions of 5980 µm × 6430 µm.

Original languageEnglish
Title of host publicationProceedings - 2024 IEEE 42nd VLSI Test Symposium, VTS 2024
PublisherIEEE Computer Society
ISBN (Electronic)9798350363784
Publication statusPublished - 2024
Event42nd IEEE VLSI Test Symposium, VTS 2024 - Tempe, United States
Duration: 22 Apr 202424 Apr 2024

Publication series

NameProceedings of the IEEE VLSI Test Symposium
ISSN (Electronic)2375-1053


Conference42nd IEEE VLSI Test Symposium, VTS 2024
Country/TerritoryUnited States

Bibliographical note

Publisher Copyright:
© 2024 IEEE.


  • adaptive dpd
  • digital pre-distortion
  • dpd
  • observation receiver
  • v2x
  • vehicle-to-everything


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