An OFDM-based radio over fiber system with channel estimation denoising and digital linearization

This work presents experimental results for a 20.3 km fiber-optic link operating at 3.5 GHz for potential Radio-over-Fiber (RoF) applications. The system employs OFDM together with denoising-assisted channel estimation and digital polynomial linearization based on a Least Squares (LS) training algorithm. To evaluate the minimum input power required to satisfy 5G EVM specifications and the resulting dynamic range enhancement, the EVM versus RF input power is characterized for both 64-QAM and 256-QAM signals. The experimental results show that the proposed compensation scheme reduces the EVM from 8.2% to 1.9% for 64 QAM and from 6.6% to 1.8% for 256 QAM.