We report the implementation of an optical-wireless 5G network based on generalized frequency division multiplexing (GFDM) and multi-Gbit/s communication. Dual-drive Mach-Zehnder modulator was employed, enabling simultaneously RF signals transport using two 5G candidate bands, namely: 26 GHz band for providing a femtocell with 2 Gbit/s throughput; 700 MHz band for enabling rural access applying a supercell. A vector signal generator provides the broadband 26 GHz signal. The Brazilian GFDM-based 5G transceiver generates the lower-frequency signal, with the advantage of low out-of-band emission. An experimental digital performance analysis illustrates the suitability of the proposed solution to address 5G requirements.
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.
We propose and report the implementation of a multiband and photonically amplified fiberwireless (FiWi) Xhaul based on radio over fiber (RoF) technology and four-wave mixing (FWM) nonlinear effect, aiming 5G applications. The proposed ultra-wideband approach enables to simultaneously transport and amplify multiple radiofrequency (RF) signals through optical links, which might be employed as backhaul, midhaul or fronthaul of cellular systems. The FWM effect, originated from the use of 35m highly nonlinear fiber piece, gives rise to RF gain, when compared to conventional RoF (CRoF) systems. We demonstrate our technique allows replacing two conventional RF amplifiers with enhanced digital performance and/or significantly increasing the system throughput in 2.4 times, attaining 12 Gbit/s. Furthermore, a dual-band (7.5 and 28.0 GHz) wireless fronthaul, preceded by a 12.5-km optical midhaul, illustrates the multiband and photonically amplified FiWi Xhaul, by means of providing performance in terms of root mean square error vector magnitude (EVM RMS) in accordance to the 3GPP recommendations and at low phase noise level. INDEX TERMS 5G networks, four-wave mixing, microwave photonics, optical-wireless networks.
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