This work reports the concept and implementation of a dual-band wireless fronthaul (FH), using a frequency selective surface (FSS)-based focal-point/Cassegrain antenna, assisted by an optical midhaul (MH). Our innovative fiber-wireless architecture enables to achieve simultaneous and extendedreach transmission over two distinct bands, namely C-and Ka-bands. The dual-band wireless FH is ensured by employing a dual-band antenna, consisting of a conventional main reflector (paraboloid) and a subreflector based on a frequency selective surface, which allows integrating a focal-point and a Cassegrain system in the same structure. It presents gain from 30 to 39.4 dBi and bandwidth from 1.1 to 4.3 GHz at 7.45 and 28 GHz, respectively. The optical MH relies on applying a dual-drive Mach-Zehnder modulator for simultaneously modulating both RF signals at the same wavelength and distribute them through a 25 km fiber optical link. Finally, the RF carriers at 7.5 and 28 GHz are radiated by the FSS-based antenna over dozens of meters wireless link. Experimental results demonstrate throughput up to 18 Gbit/s with error vector magnitude in accordance to the 3GPP Release 15 requirements, giving rise to a potential technological solution for increasing the system range, as well as reducing capital expenditure costs, footprint, weight and complexity.INDEX TERMS 5G, antennas, microwave photonics, mm-waves and telecommunications.

No abstract

The sixth generation of mobile communication (6G) systems is recently rising a lot of interest, introducing new futuristic and challenging use cases that will demand much more than just communications to become a reality. Higher throughput, lower latencies, higher number of connections will push the requirement of the future mobile networks to a new level, but also sensing, positioning and imaging will play an important role in the new foreseen use cases. The integration of techniques developed for wireless communications with those conceived for optical links will be essential to provide the infrastructure for the 6G networks. In this context, this paper presents a review on wireless and optical convergent access solutions towards the 6G systems. The manuscript brings the use cases, requirements and enablers for 6G networks including a discussion about the state-of-the-art on THz and sub-THz communications, wireless and optical convergence, visible light communication, integrated and free-space optics, new antenna designs, powerover-fiber deployments and the use of machine learning in the physical layer of future networks. By reviewing the most relevant contributions available in the literature for wireless and optical communications and presenting their main contributions, this paper clearly shows that, more than a technological trend, the convergence of wireless and optical technologies is a fundamental step towards the development of the 6G network infrastructure.

No abstract

No abstract