Sistema ópticos-sem fio 5G NR com um transmissor de múltiplos comprimentos de onda em óptica integrada

Abstract

This work addresses a solution for the implementation of radio over fiber (RoF - radio-over-fiber) systems for applications in fifth-generation (5G) wireless networks and future generations. The proposed solution is demonstrated with the application of a multiwavelength transmitter (MWT – multiwavelength transmitter) integrated into an indium phosphide platform (InP – indium phosphide), as a source for generating optical carriers. First, the photonic integrated circuit (PIC) and characterization of the MWT are presented. The PIC integrates eight tunable wavelength lasers, aiming to reduce the complexity and dimensions of the transmitter, allowing for compact, high-performance, and smaller 5G solution cost. After the characterization, a multi-band 5G optical fronthaul is implemented using two 5G new radio (NR) signals and one LTE-A signal. The signals are evaluated in two distinct scenarios, as a function of the root mean square error vector magnitude (EVMRMS), according to the requirements of 3GPP Release 15. In the first phase, three optical carriers in C-band are independently modulated with three mentioned RF signals featuring wavelength division multiplexing, whereas subcarrier multiplexing is applied to the second scenario to jointly modulate the three RF signals into a single optical carrier. Gbit/s throughput is demonstrated to validate the applicability of the integrated MWT to allow multiple applications and/or diverse RF standards. The PIC transmitter is implemented in wireless optical communication systems. The first implementation refers to a system based on the convergence between optical networks and RF networks, called fiber-wireless (FiWi) system. In this system, three RF signals, in 4G/5G standards, are simultaneously transported over a 12.5 km long RoF link. RF transmissions in the wireless medium are demonstrated using a 10 m long indoor picocell-like link and a 115-m long realistic outdoor link. The second proposal presents a 12.5 km RoF system followed by a 1.5 m free-space optics (FSO) link, targeting the end-user access network. In this proof of concept, an M-QAM signal is transmitted on only one MWT channel. The received signals in both implementations comply with the requirements of 3GPP Release 15, in terms of EVMRMS, and show a total throughput of 1.36 Gbit/s and 230 Mbit/s in the scenarios of 10 m and 115 m, respectively, and a throughput of 160 Mbit/s for the link in FSO.