Performance Enhancement in Multiband 5G NR-Radio-over-Fiber System using DPD

In this paper, we bridge experimental realization and performance investigation of multiband 5G new radio (NR) based analog radio over fiber (A-RoF) link with feedback iteration digital predistortion (FBI-DPD) methodology. The 5G NR standard at 20 GHz with 50 MHz bandwidth and flexible-waveform signal at 3 GHz which can be set as filtered-OFDM (F-OFDM), orthogonal frequency division multiplexing (OFDM), or generalized frequency division multiplexing (GFDM) with 20 MHz bandwidth is used. A dual drive Mach Zehnder Modulator having two distinct RF signals modulates a 1310 nm optical carrier using distributed feedback laser for 15 km of standard single mode fiber. The DPD method is employed for multi band 5G NR signals by utilizing generalized memory polynomial and decomposed vector rotation method. The experimental results are presented in terms of adjacent channel power ratio and error vector magnitude, suggesting that DPD method not only enhances the performance of the link but also meets the 3GPP Release 16 requirements.