Due to the economics and complexity of connecting rural and remote areas with terrestrial networks, a significant percentage of the world’s population still doesn’t have access to the internet. Just 70% of the UK had 4G mobile coverage from every operator in 2021, dropping to as low as 45% in Scotland. It’s therefore clear that more needs to be done to plug these coverage ‘notspots’ and provide universal connectivity.

In recent years, 5G non-terrestrial networks (NTNs) – otherwise known as 5G satellite communications – have been standardised by 3GPP as a way to achieve this. Satellite operators, traditional network vendors and handset manufacturers are currently figuring out their places in this new ecosystem, but it’s the handset vendors that will act as the bridge between infrastructure capabilities and end users. While some vendors, such as Samsung, seem to have decided to temporarily forgo satellite capabilities until the technology is more mature, moves from companies such as Apple show the clear investment that is being made in this sector.

The Satellite Opportunity

Many of the satellite connectivity announcements we’ve seen from handset vendors so far concern emergency situations. For example, Apple’s launch of ‘Emergency SOS via Satellite’ capabilities on the iPhone 14 focuses solely on connecting users to the emergency services when cellular or Wi-Fi coverage isn’t available. This is a high value, albeit niche, use case.

However, the long-term aim and opportunity for handset vendors and network operators is to give their users reliable connectivity for any use case, including in remote or underserved locations in order to expand their reach and provide a competitive advantage. There are plenty of areas that don’t have reliable cellular coverage, which is detrimental for both end users and the businesses located in these places. This is the issue the T-Mobile announcement with SpaceX promises to solve, with the combination of Starlink and T-Mobile’s wireless network eventually providing “near complete coverage in most places in the US – even in many of the most remote locations previously unreachable by traditional cell signals.”

While consumer handset use cases will likely drive the bulk of the demand for satellite connectivity, there is also an industrial opportunity as the adoption of 5G NTN technology will support NTN-compatible IoT devices, other industrial applications, and new use cases such as UAVs and connected cars.

“As 5G NTN technology matures and multiple networks become available there will then be a need for the approval of key satellite global frequency bands by the 3GPP and regulators.”

Peter Kibutu
Advanced Technology Lead, NTNs at TTP plc

A standardised future

While handset vendors including Apple, T-Mobile, Huawei and Bullit have already made pioneering satellite announcements, these companies are ahead of the curve as they have done so before the completion of industry standardisation. To date, handset manufacturers have only been able to provide compatibility with a single satellite provider, for example, Apple with Globalstar and Qualcomm with Iridium. This means that the satellite connectivity offered today is constrained by individual satellite networks and the proprietary technology and protocols upon which they were originally built.

Therefore, critical to the wider adoption of 5G NTN in handsets and IoT devices is the approval of industry standards. Fortunately, while it’s still early days, 5G NTNs are currently being developed as defined by 3GPP Release 17. This will provide open access to the technology and be the enabler behind new use cases that go beyond emergency comms, eventually enabling handsets to ‘roam’ between multiple satellite providers and deliver ubiquitous high-performance connectivity for any use. However, as 5G NTN technology Satellite-to-smartphone www.csimagazine.com Spring 2023 11 matures and multiple networks become available there will then be a need for the approval of key satellite global frequency bands by the 3GPP and regulators.

While standardisation and industry consolidation are on the horizon, we can still expect handset manufacturers to wait until the infrastructure is based fully on industry standards before making their move as Samsung has done, which is expected to be towards the end of the year.

Overcoming network challenges

While handset vendors continue to assess and evolve the satellite capabilities they offer, they can’t achieve this level of connectivity without the infrastructure provided by telcos, chip vendors and satellite providers. And there are a number of challenges that these players must overcome.

Firstly, the 5G infrastructure currently in place was optimised for a terrestrial environment and consequently can’t be expected to deliver services at the same level of efficiency as a non-terrestrial environment. Unlike terrestrial base stations, a satellite payload is essentially a battery-operated device operating in a very constrained and harsh environment. Each satellite constellation has unique network architectural and operational requirements which expands the list of deployment requirements when compared to terrestrial networks.

Satellite networks must also cope with more constrained link budget environments and larger beam footprints. To address this, the incumbent satellite operators have relied on bespoke waveforms and handsets that are highly optimised to deliver efficient service for a given network configuration, and will therefore need to model the 5G NTN system to maximise the available network capacity.

Significant performance enhancements can be achieved with the ‘Regenerative’ deployment model, which sees the RAN processing split across the radio unit, distributed unit and centralised unit. This architecture can enable the RU, DU and potentially other RAN components to be more easily located on satellite infrastructure instead of a Ground Station, and enables multiple satellites to connect to a single network gateway on Earth, communicating with one another through satellite links. This can enable satellite networks to be densified and more efficiently operated, with reduced latencies and higher throughputs.

Therefore, if 5G NTNs are to produce higher data rates with universal coverage, they will have to be composed of a large number of satellites and beams, each of which must be coordinated to provide seamless coverage and interoperation with existing 5G terrestrial networks. This is a complex and time-consuming task, requiring extensive satellite system engineering and 5G network modelling expertise. The best networks will be designed to optimise NTN services within a myriad of competing system design constraints. This will require careful planning and coordination between network operators and equipment vendors, and an effective strategy to jointly influence the 3GPP standards bodies.

What’s next for handset connectivity?

This is an exciting time to be a satellite ecosystem player, as we’ve already seen significant investment in this area before the standards have even been introduced. When those standards are set, we are likely to see a reduction in cost due to the spectrum and industry consolidation, and innovation will thrive and new satellite capabilities will come to the fore. From a handset perspective, this will create an inflection point for adoption, as satellite capabilities will be embedded into all chipsets and so all devices will have access to them. As further standards are set to be released next year, now is the time for the players in this space to act to influence these standards and make their mark.

This article was originally published in the Spring Issue of CSI Magazine – The past, present and future of satellite connectivity for handsets

Peter Kibutu
Advanced Technology Lead, NTNs