Open AccessExperimental demonstration of digital predistortion for orthogonal frequency‐division multiplexing‐radio over fibre links near laser resonance
Author(s) -
Vieira Luis Carlos,
Gomes Nathan Joseph
Publication year - 2015
Publication title -
iet optoelectronics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.379
H-Index - 42
eISSN - 1751-8776
pISSN - 1751-8768
DOI - 10.1049/iet-opt.2014.0160
Subject(s) - predistortion , electronic engineering , qam , orthogonal frequency division multiplexing , radio over fiber , quadrature amplitude modulation , computer science , linearity , adjacent channel power ratio , modulation (music) , wireless , telecommunications , engineering , cmos , bit error rate , physics , amplifier , channel (broadcasting) , acoustics
Radio over fibre (RoF), an enabling technology for distribution of wireless broadband service signals through analogue optical links, suffers from non‐linear distortion. Digital predistortion has been demonstrated as an effective approach to overcome the RoF non‐linearity. However, questions remain as to how the approach performs close to laser resonance, a region of significant dynamic non‐linearity, and how resilient the approach is to changes in input signal and link operating conditions. In this work, the performance of a digital predistortion approach is studied for directly modulated orthogonal frequency‐division multiplexing RoF links operating from 2.47 to 3.7 GHz. It extends previous works to higher frequencies, and to higher quadrature amplitude modulation (QAM) levels. In addition, the resilience of the predistortion approach to changes in modulation level of QAM schemes, and average power levels are investigated, and a novel predistortion training approach is proposed and demonstrated. Both memoryless and memory polynomial predistorter models, and a simple off‐line least‐squares‐based identification method, are used, with excellent performance improvements demonstrated up to 3.0 GHz.