A Wideband Pulse-Modulated Polar Transmitter with Low-Complexity Digital Predistortion
Journal
IEEE Microwave and Wireless Technology Letters
Journal Volume
33
Journal Issue
12
Date Issued
2023-12-01
Author(s)
Abstract
In this letter, a wide bandwidth power amplifier (PA) using pulse modulation is presented. Pulse modulation significantly reduces the amount of thermal memory. However, with a large signal bandwidth, significant matching-related memory effect exists. A compensation equalization filter is proposed to compensate the in-band gain/phase variation, such that simple memoryless digital predistortion (DPD) can still be utilized. A prototype transmitter system is constructed using a commercially available base station PA for validation. Measurements are performed using a 256-QAM fifth-generation new radio (5G NR) downlink multicarrier modulated signal at 3500 MHz with an instantaneous bandwidth of 100 MHz. Using memoryless DPD and the proposed filter, the overall system achieved passing the -45-dBc downlink spectral requirements for the 5G NR standard showing negligible thermal memory effect in PAs using pulse modulation.
Subjects
Digital pulsewidth modulation (DPWM) | equalization filter | fifth-generation new radio (5G NR) | power amplifiers (PAs) linearization | radio frequency (RF) transmitter | small-cell base stations
SDGs
Type
journal article