Panelists at the Open RAN Forum discuss how Open RAN is helping solve some of the biggest non-terrestrial 5G hurdles
At this year’s Open RAN Forum, Cambridge Consultants’ Director of Wireless Technology Tim Rogers asserted that Open RAN architecture “accelerates the development of high-value, novel use cases,” using the company’s non-terrestrial 5G network collaboration with AccelerComm as an example.
Non-terrestrial 5G networks, said Rogers, have “real potential” to provide more environmentally sustainable coverage than terrestrial or satellite constellations. However, these networks also come with unique challenges, such as needing particularly “tight beamforming” that can behave dynamically because the satellites platforms are moving. “We end up needing very large active antenna arrays to give this performance… size and the weight of course of arrays become a considerable challenge. And then also at these altitudes… the atmosphere is very thin, and so cooling is also a challenge,” he continued.
According to Rogers, Open RAN, though, has made a notable difference when it comes to addressing some of these challenges. “Before the [Open RAN] ecosystem existed, we found ourselves having to develop a lot of the components in the radio systems from the ground up… simply because there was no alternative.” Now, though, he said the growing list of independent vendors courtesy of the burgeoning Open RAN ecosystem is delivering those alternatives.
“We can run develop[ment] from a greenfield, we can build these elements in. And while system integration may not be perfect, this is lowering the effort, the timescales required to deliver some of these novel solutions,” he said.
AccelerComm’s Founder and CTO Rob Maunder joined Rogers to explain how Cambridge Consultants used Open RAN standardization to help the company “fast track” the development of its LEOphy system, a layer 1 modem designed for low-earth orbit satellite communication. LEOphy, said Maunder, has Open RAN interfaces between various parts of the system, including one between the software and hardware accelerators in the physical layer, one between the high PHY and layer two above, as well as ORAN standardized interfaces at the accelerator abstraction layer.
“The focus of the collaboration for the Cambridge Consultants’ team was the extraction of a layer one feature set requirements,” he explained. “The Cambridge team also implemented and simulated and validated particular software features.” The companies built a test environment that included test equipment, signal generators, signal analyzers and a stand-in for the layer two, which can stimulate the layer one as well as the test equipment with commands to configure it into particular modes. “And this test environment is fully automated and it represents CI/CD, so whenever a line of code gets changed, the complete suite of tests can be rerun very quickly,” he added.
Maunder also dug deeper into the beamforming challenge first mentioned by Rogers, explaining the “beam hopping arrangement” for satellites allows for coverage across different geographical regions, but also that only a subset of the beams is activated at any given time. “Over time, on a very fast basis, the different beams are being hopped on and off… and this imposes… challenges for the deployment of a 5G and TN system because the terrestrial networks don’t quite have that same concept… impos[ing] particular constraints within which the rest of the network optimization must work,” he stated.
Open RAN standardization, he continued, introduces new interfaces to allow the necessary coordination for “beam hopping management to impose constraints upon the layer two scheduler and for the layer two scheduler,” allowing for better beam hopping management to ensure service is being delivered to those demanding it.
“Deployment of a 5G non-terrestrial network system is an emerging opportunity [that] is going to have a big impact on the world,” summarized Maunder. “There are a lot of challenges there. These are challenges that AccelerComm has faced and overcome, and we’re now in a very strong position to deliver these systems into diverse deployments that will be finding their way into space in the coming years.”
