| MS Seminar

Name of the Speaker: Ms. NIRUBANA J (EE21S126)
Guide: Dr. Radha Krishna Ganti
Venue: ESB-244 (Seminar Hall)
Online meeting link: http://meet.google.com/bnv-zfye-xek
Date/Time: 23rd July 2025 (Wednesday), 2:00 PM
Title: Integrated Frontend for enhancing linearity and efficiency in 5GNR system: Filters, Crest Factor Reduction and Digital Predistortion.

Abstract :

An integrated front-end is essential for achieving enhanced linearity and efficiency in 5G New Radio (NR) systems. This work presents the design and implementation of a transmitter front-end architecture incorporating digital filters, Crest Factor Reduction (CFR), and Digital Predistortion (DPD) to address challenges caused by power amplifier (PA) nonlinearities and the high Peak-to-Average Power Ratio (PAPR) of Orthogonal Frequency Division Multiplexing (OFDM) signals. High PAPR forces the PA into its saturation region, resulting in signal distortion, adjacent channel interference, and degraded spectral performance. CFR reduces signal peaks to allow more efficient PA operation, while DPD compensates for PA nonlinearities to maintain Adjacent Channel Leakage Ratio (ACLR).Both modules are implemented in the digital baseband with a focus on minimizing hardware complexity while ensuring real-time operability. A memory polynomial-based DPD model is adopted, with Least Squares estimation performed on captured transmit (TX) and observation (ORX) data. Delay alignment is achieved and calibration routines are applied to maintain accuracy across multiple transmit channels. The system is integrated within a TDD 5G NR architecture and validated on a multi-channel testbed, demonstrating an ACLR improvement and confirming the effectiveness of the proposed front-end in practical deployment scenarios.