The Backhaul and Radio Access Integrating LEO (BRAIL) project is a Catapult led initiative exploring cutting edge hybrid backhaul connectivity solutions for 4G and 5G services. Funded by the UK Space Agency, and with consortium partners OneWeb, Livewire Digital and Strathclyde University (with support from subcontractors at the University of Surrey and Tor Vergata, University of Rome), we successfully explored the use of a multi-satellite backhaul (mixture of LEO (Low Earth Orbit) and GEO (Geostationary Orbit) satellites) and Smart Routing technology to provide a seamless and robust connection when one service is unavailable. In essence, BRAIL demonstrated that LEO is a suitable solution as a satellite backhaul when combined with GEO. The project, consisting of three focus areas explored 4G/LTE Remote Backhaul, 5G Remote Backhaul, and Direct-Satellite 5G.
- 4G/LTE Remote Backhaul
The Catapult utilised OneWeb and KA-SAT terminals at Wescott to test 4G/LTE remote backhaul using LEO and GEO satellite systems. 4G is currently more widely and readily available than 5G, so testing on this network proves OneWeb’s service and creates immediate commercial opportunities.
The consortium successfully connected a 4G base station to the core network via a Smart Routing technology that bonds and migrates between dissimilar LEO and GEO satellite links. Service continuity was demonstrated through a VoLTE voice call, in which the connection proved seamless despite the deliberate interruption to the service of each satellite in turn. This has clear potential for health and emergency services, providing support for other Catapult projects such as the Healthy Living Lab.
- 5G Remote Backhaul
The second focus area explored the use of LEO satellite connectivity as part of a robust and resilient 5G backhaul technology. Data services used to demonstrate the end-to-end system which was based on key 3GPP Releases 15 and 16 features. The following advance architectures were implemented:
- Stand Alone (SA) and Non-Stand Alone (NSA) access. In the SA architecture the 5G New Radio (NR) Radio Access Network (RAN) is backhauled to the 5G core network which provides full end-to-end system level advantages such as lower latency and higher speeds. NSA, on the other hand, connects the 5g New Radio RAN to existing 4G/LTE Core Network. Today all commercial 5G implementations are based on NSA only
- Neutral Host architectures, where many different operators share the 5GNR RAN and backhaul infrastructure benefiting from savings in CAPEX/OPEX and resources
- The Distributed User Plane Function (UPF) is deployed closer to RAN (User) to separate Control plane over satellite and User plane over the terrestrial link to optimise the use of backhaul – that results in lower latency and higher data rates
- Multi-Access Edge Compute (MEC) – where a local compute capability is deployed closer to the RAN to improve response time to the connected handsets (UEs) and once again optimise the use of backhaul.
By demonstrating the efficacy of LEO as a remote backhaul using SA 5G, BRAIL provides the UK first in advanced 5G techniques, providing commercial operators evidence of improved latency and connectivity solutions using Stand Alone infrastructure.
- Direct Satellite – 5G Access Scenario
The last scenario focus on the use of direct 5G link to Non-Terrestrial Networks, through the LEO satellites, to provide seamless User Experience. The consortium assessed the technical challenges and concluded to strategic roadmaps in preparation for 3GPP Release 17 later in 2021. The team concluded that more research needed to be carried out in future projects.
What does this mean?
BRAIL made huge steps forward in demonstrating the technical feasibility of advanced 5G concepts, towards a more connected world. The innovative use of LEO satellite backhaul enables cost-effective delivery of solutions to remote and rural areas, supporting commercial operators and use cases for health and emergency services, where seamless connectivity improves the efficiency and safety of response teams.
Aside from technical advances, the BRAIL project built successful relationships that benefit the UK space sector and creates opportunities for future collaboration between consortium partners. The Catapult was able to integrate and engage OneWeb into the UK’s space ecosystem, who have been implementing a mega-constellation of LEO satellites with the aim to provide ubiquitous internet connectivity. The 5G step out centre at Westcott is the first place in the UK to deploy OneWeb terminals, which played a key role in each work package.
The BRAIL project concluded in March 2021.
Click here to find out more about the BRAIL project. Or, to learn more about the Catapult’s role in connectivity and the use cases it supports, please visit the Ubiquitous Connectivity page on the Catapult website.