High-capacity 5G fronthaul networks based on optical space division multiplexing

\u3cp\u3eThe introduction of 5G mobile networks, bringing multi-Gbit/s user data rates and reduced latency, opens new opportunities for media generation, transport and distribution, as well as for new immersive media applications. The expected use of millimeter-wave carriers and the strong network densification resulting from a much reduced cell size--which enable the expected performance of 5G--pose major challenges to the fronthaul network. Space division multiplexing (SDM) in the optical domain has been suggested for ultra-high capacity fronthaul networks that naturally support different classes of fronthaul traffic and further enable the use of analog radio-over-fiber and advanced technologies, such as optical beamforming. This paper discusses the introduction of SDM with multi-core fibers in the fronthaul network as suggested by the blueSPACE project, regarding both digitized and analog radio-over-fiber fronthaul transport as well as the introduction of optical beamforming for high-capacity millimeter-wave radio access. Analog and digitized radio-over-fiber are discussed in a scenario featuring parallel fronthaul for different radio access technologies, showcasing their differences and potential when combined with SDM.\u3c/p\u3

Joint Access-Backhaul Perspective on Mobility Management in 5G Networks

The ongoing efforts in the research development and standardization of 5G, by both industry and academia, have resulted in the identification of enablers (Software Defined Networks, Network Function Virtualization, Distributed Mobility Management, etc.) and critical areas (Mobility management, Interference management, Joint access-backhaul mechanisms, etc.) that will help achieve the 5G objectives. During these efforts, it has also been identified that the 5G networks due to their high degree of heterogeneity, high QoS demand and the inevitable density (both in terms of access points and users), will need to have efficient joint backhaul and access mechanisms as well as enhanced mobility management mechanisms in order to be effective, efficient and ubiquitous. Therefore, in this paper we first provide a discussion on the evolution of the backhaul scenario, and the necessity for joint access and backhaul optimization. Subsequently, and since mobility management mechanisms can entail the availability, reliability and heterogeneity of the future backhaul/fronthaul networks as parameters in determining the most optimal solution for a given context, a study with regards to the effect of future backhaul/fronthaul scenarios on the design and implementation of mobility management solutions in 5G networks has been performed.Comment: IEEE Conference on Standards for Communications & Networking, September 2017, Helsinki, Finlan

Performance analysis of multiple radio-access provision in a multicore-fibre optical fronthaul

[EN] In this work we report a comprehensive experimental study targeting the dimensioning of the next-generation multicore-fibre (MCF) optical fronthaul employing space-division multiplexing (SDM). This fronthaul is capable of simultaneous provision of multiple radio-access technologies (multi-RATs) with advanced multi-antenna MIMO capabilities per RAT. The different parameters required for fronthaul dimensioning are evaluated considering state-of-the-art 4G LTE-Advanced altogether other legacy wireless standards in operation nowadays. In particular, the modulation characteristics, the antenna quality requirements (in terms of EVM, phase error or rho) and the signal-to-noise ratio (SNR) thresholds are evaluated employing fully-standard cellular signals transmitted on a multicore fibre (MCF) fronthaul. The study includes bi-directional signal transmission and multi-antenna MIMO multiplexing. The MCF optical fronthaul is evaluated with a multiplexed transmission of 2G, 3G, 3.9G and 4G MIMO signals in radio-over-multicore-fibre (RoMCF) employing a commercially available four-core MCF. The SNR requirements at the transmitter antenna are obtained for each cellular signal considering GSM, EDGE, EGPRS2-A, cdma2000 1xEV-DO, UMTS HSPA+ and LTE-Advanced standards. LTE-Advanced singleantenna and two-antenna systems implementing 2 x 2 MIMO transmission can be accomplished with SNR levels over 25 dB. In the case of LTE-Advanced 4 x 4 MIMO multiplexing over four cores of MCF media, 32 dB SNR is needed to achieve almost four times provided bitrate per user.This research was supported in part by Spain National Plan MINECO/FEDER UE TEC2015-70858-C2-1-R XCORE and GVA AICO/2018/324 NXTIC projects. The work of M. Morant is supported by Spain Juan de la Cierva, Spain IJCI-2016-27578 grant and Fundacion BBVA Leonardo 2018 HYPERCONN project.Morant, M.; Llorente, R. (2019). Performance analysis of multiple radio-access provision in a multicore-fibre optical fronthaul. Optics Communications. 436:161-167. https://doi.org/10.1016/j.optcom.2018.11.036S16116743

Transition technologies towards 6G networks

[EN] The sixth generation (6G) mobile systems will create new markets, services, and industries making possible a plethora of new opportunities and solutions. Commercially successful rollouts will involve scaling enabling technologies, such as cloud radio access networks, virtualization, and artificial intelligence. This paper addresses the principal technologies in the transition towards next generation mobile networks. The convergence of 6G key-performance indicators along with evaluation methodologies and use cases are also addressed. Free-space optics, Terahertz systems, photonic integrated circuits, softwarization, massive multiple-input multiple-output signaling, and multi-core fibers, are among the technologies identified and discussed. Finally, some of these technologies are showcased in an experimental demonstration of a mobile fronthaul system based on millimeter 5G NR OFDM signaling compliant with 3GPP Rel. 15. The signals are generated by a bespoke 5G baseband unit and transmitted through both a 10 km prototype multi-core fiber and 4 m wireless V-band link using a pair of directional 60 GHz antennas with 10 degrees beamwidth. Results shown that the 5G and beyond fronthaul system can successfully transmit signals with both wide bandwidth (up to 800 MHz) and fully centralized signal processing. As a result, this system can support large capacity and accommodate several simultaneous users as a key candidate for next generation mobile networks. Thus, these technologies will be needed for fully integrated, heterogeneous solutions to benefit from hardware commoditization and softwarization. They will ensure the ultimate user experience, while also anticipating the quality-of-service demands that future applications and services will put on 6G networks.This work was partially funded by the blueSPACE and 5G-PHOS 5G-PPP phase 2 projects, which have received funding from the European Union's Horizon 2020 programme under Grant Agreements Number 762055 and 761989. D. PerezGalacho acknowledges the funding of the Spanish Science Ministry through the Juan de la Cierva programme.Raddo, TR.; Rommel, S.; Cimoli, B.; Vagionas, C.; Pérez-Galacho, D.; Pikasis, E.; Grivas, E.... (2021). Transition technologies towards 6G networks. EURASIP Journal on Wireless Communications and Networking. 2021(1):1-22. https://doi.org/10.1186/s13638-021-01973-91222021

Towards efficient and reconfigurable next-generation optical fronthaul networks for massive MIMO

This paper summaries our recent research on digital radio over fibre (DRoF) based optical fronthaul links and experimentally demonstrates a novel last-mile wireless coverage system incorporating data compression, time-division multiplexing (TDM) based packetization, and wavelength division multiplexing (WDM) based optical transmission. Compression reduces the fronthaul data rate required per service by a factor of 3 when compared with the common public radio interface (CPRI) standard, enabling efficient radio resource distribution over optical fibre infrastructure. The new packetization mechanism and WDM architecture enable fully reconfigurable resource allocation in a fronthaul network for 20MHz-bandwidth RF inputs with 64x64 MIMO carried over an aggregated compressed optical data rate of 32Gbps using 4 wavelengths. The experimental results show over 40dB RF dynamic range with < 8% error value magnitude (EVM) for the 64 quadrature amplitude modulation (64-QAM) input signals across all the WDM channels while the lowest EVM is less than 2%. Meanwhile, this field-programmable gate array (FPGA) based DRoF system allows flexible, software definable and easy-scalable dynamic antenna resource allocatio

Next-Generation Optical Fronthaul Systems Using Multicore Fiber Media

(c) 2016 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other users, including reprinting/ republishing this material for advertising or promotional purposes, creating new collective works for resale or redistribution to servers or lists, or reuse of any copyrighted components of this work in other works.This paper proposes and investigates the use of multicore fiber (MCF) media performing space-division multiplexed transmission for next-generation optical fronthaul systems. We report the experimental demonstration of combined radio-over-fiber (RoF) transmission of full-standard LTE-Advanced (LTE-A) and WiMAX signals providing fronthaul connectivity in 150m of 4-core fiber (4CF), transmitting simultaneously fully independent wireless services. Operating in linear and nonlinear optical power regimes, the experimental evaluation verifies that the error vector magnitude (EVM) is not degraded when intercore and intracore Kerr nonlinearities are excited in MCF with high input power levels. As a result, nonlinear regime is proposed as a key factor to reduce the temporal EVM fluctuation induced by the random nature of the intercore crosstalk in MCF. In addition, MCF fronthaul applied to converged fiber-wireless polarization multiplexed passive optical networks is demonstrated to transmit LTE-A and WiMAX signals over two orthogonal optical polarizations. The polarization-multiplexed signal is transmitted in RoF over 25.2 km of standard single-mode fiber and then demultiplexed and injected in different cores of the 4CF to provide fronthaul connectivity. Finally, the extension of multicore optical fronthaul capacity is proposed using MIMO LTE-A signals. The tolerance of the MIMO LTE-A RoF transmissions to in-band crosstalk is reported and compared to single-input single-output (SISO) configuration. The experimental results indicate that MIMO configuration is more tolerant than SISO to in-band crosstalk considering both internal and external interferences. MIMO and SISO configurations are compared when transmitted in RoF over a 4CF operating in linear and nonlinear regimes and core interleaving nonlinear stimulation is proposed to reduce the temporal and spectral EVM fluctuation when the same wireless standard is propagated in each core.This work was supported in part by Spain the National Plan Project XCORE TEC2015-70858-C2-1-R and RTC-2014-2232-3 HIDRASENSE. The work of A. Macho was supported by BES-2013-062952 F.P.I. Grant. The work of M. Morant was supported in part by UPV postdoc PAID-10-14 program.Macho-Ortiz, A.; Morant Pérez, M.; Llorente Sáez, R. (2016). Next-Generation Optical Fronthaul Systems Using Multicore Fiber Media. Journal of Lightwave Technology. 34(20):4819-4827. https://doi.org/10.1109/JLT.2016.2573038S48194827342