Widespread Satcom Role in 5G Thought Still Years Out

March's Release 17 included 5G support for satellite communications, allowing low data rate services for handsets and adapting narrowband IoT operations to satellite communications. Work is underway at the ITU in its Working Party 4B to ensure its IMT-2020 standard for 5G has a satellite component, said Jennifer Manner, EchoStar senior vice president-regulatory affairs. That effort will likely finish after WRC-2023, she said.

Release 17 "was a significant step" toward satcom having a 5G role, emailed Derek Long, Cambridge Consultants telecommunications head. There were previous initiatives to include nonterrestrial networks in cellular technologies, particularly as backhaul for remote base stations, but with Release 17 "we are starting to see the inclusion of these technologies and architectures in a systemised manner," he said. He said Release 18 "provides critical interworking functionality and it typically takes a few years after standardisation for technologies to find their way into commercial products." He said gateway-based services could be possible within two to three years, but direct-to-terminal services will take longer because the technology has to be standardized and then mature. He said terminal vendors have to see a business case for implementing the tech in their devices, and low earth orbit constellation operators will have to introduce the tech into their systems. He said there's increased interest in satcom-based IoT, which Release 17 opened the door to, and initial systems have launched.

Many expect satcom's role to include backhaul and providing direct connectivity to handsets. Cambridge's Long said the technology to provide direct-to-handset connectivity "has some way to go particularly with the development of more advanced antennas for use on space-based platforms that can provide the necessary link budget with a manageable form factor and thermal budget." But in the meantime, drone-based stratosphere platforms "are capable of providing a good low cost coverage solution," he said. Alex Besen, head of mobile industry consultancy Besen Group, said the early applications for satellite-delivered 5G likely include public safety, military, offshore drilling and farming -- anything that might take place away from robust terrestrial wireless networks. He said satcom operators should focus more on enterprise and IoT services, with consumer service likely to be a more niche offering.

Release 17 supports satellite-delivered text messaging now, though voice service might require what's being worked on with Release 18, said Juan Montojo-Bennassar, Qualcomm vice president-engineering. There's far more flexibility in 5G than in past generations, making adaptation, including use of satcom, easier, he said. He said the S band could readily accommodate direct satellite/handset traffic, and 3GPP's Release 18 will include performance requirements involving Ku and Ka bands. Release 18 is to be finalized in March 2024, though satcom operators could work now based on it, he said. There might be some changes in underlying waveforms, and terminals might need some adjustments based on Release 18, but satellites themselves should be unaffected, he said.

The intricacies of past standards make backhaul over satellite difficult, but 5G being easier should accelerate deployment, said Northern Sky Research analyst Lluc Palerm. Before satellite/handset 5G service takes off, the standard first needs to be implemented in chipsets, he said. That capability could take a couple of years to come to mobile phones, he said, though operators like Lynk, AST and Omnispace are working on variations of that. "There is going to be a lot of competition around this space in coming years," he said. Palerm said chipset manufacturers seem willing to incorporate satcom frequencies into their chipsets; L band isn't that far from spectrum used terrestrially so it's not a big investment.

How many satellite operators the 5G can support is "the million-dollar question," Besen said. He said SpaceX's Starlink could have a particular advantage in pricing because it has its own launch capabilities.

With "broad, multinational support among regulators and industry stakeholders," Release 17 will let satellite operators have "global economies of scale, achieve terrestrial interoperability, slash technology development and production costs, and accelerate the pace of innovation," Omnispace representatives told an aide to Commissioner Brendan Carr, per an FCC International Bureau filing earlier this month. The company urged allowing nonterrestrial operations in the S band for better 5G coverage. It said opening the S band "offers a better strategy for overcoming traditional barriers to deploying mass-market services that integrate satellite and terrestrial networks than ad hoc proposals to operate non-terrestrial networks in spectrum bands reserved for terrestrial uses."