Performance Study of Channel Pre-Equalisation in Mm-Wave ARoF System for 5G and B5G Networks

Fifth generation (5G) and beyond 5G (B5G) mobile communications networks will utilize fiber optical infrastructure to provide low latency and high data rate services for customers worldwide. In this paper, we experimentally develop a hybrid analog radio-over-fiber (ARoF) system and investigate its performance for Ka-band millimeter wave (mm-wave) transmission for 5G and B5G network implementation. The experimental setup aims to design a hybrid ARoF transmission system and evaluate signal transmission performance at different Ka-band (26.540 GHz) mm-wave frequencies considering distortions introduced by electrical components and optical nonlinearities originating from the fiber optical transmission part. In particular, Ka-band is especially interesting for 5G and beyond 5G (B5G) network technology as it provides mm-wave benefits with lower implementation costs compared to higher frequency mm-wave bands as V-band (40–75 GHz) or W-band (75–110 GHz). Several Ka-band frequencies, which are considered for the mm-wave 5G network deployment in Europe, China, the US, Japan, and other world regions, are selected for further pre-equalization implementation and investigated in this research. The hybrid ARoF mm-wave transmission system's performance and improvability are evaluated at different Ka-band frequencies to determine the most efficient spectrum range for efficient 5G and B5G network deployment. In this paper, performance enhancements of the ARoF system by compensating distortions of transmission system components due to nonlinear frequency response by pre-equalization are experimentally obtained. Channel pre-equalization is investigated for transmission quality improvements, allowing to significantly reduce the impact of optical nonlinearities and distortions introduced by electrical components, leading to significant improvement of the received signal BER.