This article reports the implementation and experimental performance investigation of a DSP-based flexible-waveform fiber-wireless (FiWi) system for 5G enhanced mobile broadband (eMBB) and new vertical applications. Our radio over fiber-based fronthaul solution uses a wavelength-division-multiplexing passive optical network (WDM-PON) infrastructure, from a commercial Internet service provider, to enable 5G operation over multiple frequency bands, including: a DSP and flexible waveform-based signal at 788 MHz, which can be set as generalized frequency division multiplexing (GFDM) or filtered orthogonal frequency division multiplexing (F-OFDM); 5G new radio (NR) signals at 3.5 or 26 GHz in accordance to 3GPP Release 15; an additional vector 26 GHz signal with bandwidth of up to 800 MHz. The DSP-based functionality provides digital pre-distortion (DPD), besides the real-time waveform generation. Experimental results demonstrate 4.41 Gbit/s total throughput in the air in accordance to the 3GPP requirements, as well as an innovative low-latency M2M application based on PROFINET standard.

The fifth-generation of mobile network (5G) and beyond requires a radio access network (RAN) update in order to cope with the incoming increase of wireless data traffic and new applications. In this context, we propose an efficient optical-wireless architecture applied to the non-standalone (NSA) 5G new radio (NR) framework. Several distinct electrical- and optical-based fronthaul configurations combining free-space optical (FSO), wireless links, and radio over fiber (RoF) techniques were implemented and properly analyzed for selection according to network operator deployment requirements. In addition, visible light communication (VLC) was investigated as a future access network technology when immunity to electromagnetic interference is paramount. Experimental results demonstrated fourth-generation of mobile network (4G) and 5G coexistence at Gbit/s throughput and error vector magnitude (EVM) in accordance with 5G NR Release 15.

We propose and demonstrate the use of a monolithically integrated multi-wavelength transmitter for multiband 5G new radio (NR) radio-over-fiber (RoF) systems, simultaneously operating in the standalone (SA) and non-standalone (NSA) modes. The novel integrated photonic circuit, integrating eight tunable and directly modulated distributed feedback lasers, aims to reduce the transmitter complexity and footprint, enabling compact, high-performance and low-cost 5G solutions for frequencies up to 10 GHz. We report the implementation of a 4G/5G shared optical mobile fronthaul using two 5G NR and a LTE-A signals, evaluated in two distinct scenarios, as a function of root mean square error vector magnitude (EVM-RMS) and in accordance to the 3GPP Release 15 requirements. In the first phase, three optical carriers in C-band are independently modulated with three mentioned RF signals, whereas subcarrier multiplexing (SCM) is applied to the second scenario for jointly modulating an optical carrier at 1554 nm. Gbit/s throughput is demonstrated for validating the applicability of our monolithically integrated multi-wavelength transmitter either for enabling multiapplication and/or diverse RF standards, using a single wavelength or multiservice exploiting different wavelengths from an unique optical source.

This letter presents a non-standalone 5G new radio (NR) multiband fiber-wireless (FiWi) system implemented using an integrated multi-wavelength transmitter with direct modulation. In this system, three 4G/5G RF signals are simultaneously transported over a 12.5-km long radio over fiber (RoF) link, before being amplified and radiated: a 20-MHz 5G NR signal at 788 MHz; five 20-MHz LTE subcarriers at 2.6 GHz; a 100-MHz 5G NR signal at 3.5 GHz. Wireless transmissions through a 10-m long indoor picocell-like link and a 115-m long realistic outdoor wireless link are demonstrated. All 4G and 5G received signals comply with the 3GPP Release 15 requirements, in terms of EVM _RMS , except for 16 QAM at 3.5 GHz on the 115-m link. Experimental results demonstrate a total throughput of 1.36 Gbit/s and 230 Mbit/s on the 10-m and 115-m scenarios, respectively.

This paper presents performance and limits of operation for harmonic coexistence of digital television (DTV) and TV White Space (TVWS) signals considering various interference scenarios. The coexistence was evaluated through results obtained on practical tests. It assesses DTV receiver performance, integrated services digital broadcasting - terrestrial (ISDB-T) standard, under main modulation schemes against representative TVWS signals, including commercial standards like long term evolution (LTE) and 5G new radio (5G NR), as well as two signals from the Remote Area Access Network for the 5th Generation (5G-RANGE) transceiver using filtered orthogonal frequency division multiplexing (F-OFDM) and generalized frequency division multiplexing (GFDM) techniques. 5G-RANGE is innovative brazilian TVWS solution developed to establish long range communication. Notably, techniques such as GFDM/F-OFDM on the 5G-RANGE showed superior performance to Fourth-generation (4G)/Fifth-generation (5G) signals in most tests, positioning themselves as viable alternatives within the TVWS spectrum. The results offer detailed insights into DTV receiver performance limits under diverse interferences, providing crucial insights for effective and high-quality utilization of the available spectrum.

This paper presents the results of field tests conducted in the project “Implementation of TV White Spaces (TVWS) for Internet Access in Brazil”. This study evaluates the feasibility and regulatory implications of TVWS in rural and remote areas. TVWS systems are promising for sensor network applications, enabling efficient and long-range connectivity. The experiments assess the coexistence of TVWS signals, applying, for example, the Remote Area Access Network System for the Fifth Generation (5G-RANGE) using the generalized frequency division multiplexing (GFDM) technique, with the Integrated Services Digital Broadcasting–Terrestrial (ISDB-T) system. Laboratory tests determined the protection ratio (PR) between digital television (DTV) signals and interfering signals, with minimum PR values of $-31.38$ dB on channel n$-1$ and $-33.24$ dB on channel $n+1$ for 5G-RANGE using GFDM, highlighting its low out-of-band emission (OOBE). Field tests confirmed the laboratory results, with the worst recorded PR causing interference being $-30.2$ dB on channel $n-1$. The power restriction to 1 Wp limited coverage, allowing 96 Mbps in 24 MHz BW at 14.7 km from the base station. These results highlight that regulatory adjustments can be made to support TVWS deployment in Brazil.