The BRAVE technology applies to short-range or line-of-sight communication scenarios that must deliver ultra-high data rates, in order to solve congestion (in backhaul network or server farms) or enable future challenging aplications (e.g. multi-user high-quality VR).
Future wireless fronthaul/backhaul is one candidate for the exploitation of those frequencies. The last-mile pre-5G networks rely on two separated segments: the user access, and the backhaul access, that mostly consists in line-of-sight (LoS) microwave or ﬁber-based links connected to a gateway. Innovative solutions for wireless small-cell backhauling are now emerging which use the sub-6GHz bands to reach nonline-of-sight (NLoS) multi-points, or rely on a mesh streetlevel architecture by operating at mmW frequency and compatible with high-data rate. All those solutions are using multi-carrier OFDM waveform, and most of them implements beamforming. The effort for achieving 5G and future B5G requirements has to be done at the same pace on the user access and the backhauling segments in order to avoid any bottleneck effect.
As most processing that was traditionally done at the base stations or at the access points is intended to be deported to the core of future C-RAN networks, the requirements for high capacity and low latency at the ﬁxed last-mile wireless links (or fronthaul) will be even higher. Line-of-sight wireless fronthaul/backhaul technology based on above-90GHz spectrum is viewed as a relevant extension of the emerging mmW commercial solutions in order to provide the expected speed (hundreds of GBit/s) to the access points installed at the user premises or being part of the mobile access network. Several use cases of interest for Tbits/s systems operating above 90 GHz have been already identiﬁed. They will serve in the deﬁnition of the BRAVE solution requirements, evaluation and demonstration. Those use cases are:
- Kiosk application: very short-range (up to few meters) with very-high downlink data rate link, with possibly connection to several simultaneous users;
- Resolution of congestion issues in server farms;
- Small-range hot-spots with limited user mobility and demanding applications like virtual or augmented reality, high-resolution video ;
- Wireless backhaul infrastructure to deliver ultra-high data throughput and capacity
The envisioned ultra-dense network topology in urban areas with extreme data rate, capacity and latency requirements makes the ﬁber-based backhauling highly desirable, but sometimes complicated due to current ﬁber networks penetration (variable from one country to the other) and related extension cost. High data rate wireless backhauling is a valuable competitive technology, which beneﬁts from lower deployment costs and constraints. LoS or nearLoS wireless xhaul (front or backhaul) technology based on above-90GHz spectrum is viewed as a relevant extension of the emerging mmW commercial solutions in order to provide the expected speed (hundreds of GBit/s) to the access points installed at the user premises or being part of the mobile access network.
In-street mesh deployment will permit to feed a large number of remote access points via the wireless xhaul connected to a local internet access. The Fixed Wireless Access (FWA) is another possible backhauling application, where the mesh high-frequency infrastructure gives connectivity to the ﬁxed CPE’s (Customer Premise Equipment) installed on the rooftop or fac¸ade of houses, apartment buildings, ofﬁces, etc. This alternative to ﬁber optic connections is today gaining popularity in the United States (among other countries).