Enhanced coverage though optical beamforming in fiber wireless networks

High-Capacity 5G Fronthaul Networks Based on Optical Space Division Multiplexing

“…By transporting 5G NR conform orthogonal frequency-division multiplexing (OFDM) signals in an intermediate frequency-over-fiber (IFoF) configuration and relying on photonic upconversion for mm-wave generation, blueSPACE establishes a transparent fronthaul link and directly enables analog beamforming in the optical domain. By implementing full matrix-type beamforming networks [9], [23] blueSPACE achieves true multi-beaming from a single antenna array.…”

“…The burden placed by such applications on the underlying radio access network (RAN) in terms of required data rates, quality of service and acceptable latency requires major transformations in the network and the introduction of new strategies and technologies [7], [8]. In the radio frequency (RF) access segment the required multi-Gbit/s user data rates necessitate the utilization of extended spectrum ranges, namely the introduction of millimeter wave (mm-wave) carriers, a reduction in cell size, as well as the use of multiple-input multiple-output (MIMO) signalling or beamforming to increase the signal to noise ratio (SNR) or received powers [8], [9].…”

Beyond 5G - wireless data center connectivity

“…12,13 The latter is key as it greatly increases spatial reuse of spectrum and allows concurrent transmission of many beams -the larger the array the larger the number of non-overlapping beams and the larger overall antenna gain -, which in combination enable the levels of connection density and required capacities for data center networks. The development of the required beamforming networks or arrays that adapt a number of incoming signals targeted at different beams into a number of outgoing signals to feed the antenna array -where outgoing signal each carries all incoming signals but at different differential delays -has greatly progressed with the development of 5G, 25,26 but further technological advances can be expected, reducing their cost, footprint and energy consumption.…”

Millimeter Wave Hybrid Photonic Wireless Links - Also for Broadcast?

“…Similar to the use of highly directive antennas, the use of beamforming can provide increased link performance, while partially mitigating the reduction in coverage by allowing the direction of the beam to be steered [6], [7]. Such flexibility comes at the cost of requiring antenna arrays with tunable differential delays between the feeding signals -typically achieved through electrical phase shifters, true time delays or, more recently, through optical beamforming networksand with a gain in directivity directly proportional to the dimensions of the array [7].…”

“…While both achieve significant gain in the overall system capacity by increasing the number of antenna elements at both ends, i.e., by employing spatial diversity, they differ significantly in the underlying strategy. While for sub 6 GHz systems MIMO processing is performed digitally, for mm-wave systems analog beamforming is considered more promising to generate narrow, focused beams to deliver better signal quality to the targeted user(s) [4], [7]. This paper will first review the trade-off between link directivity, achievable capacity and coverage area, highlighting the difference between highly directive point-to-point links, transmissions supported by beamforming, -steering or -switching and such where mm-waves are employed for distributed access.…”