Forty years ago, satellite telephony and cellular were adversaries, vying for the emerging market of businesspeople and consumers who wanted anytime, anywhere connectivity. For example, Iridium was born after the wife of a Motorola engineer couldn’t call her clients from her mobile phone while vacationing in the Bahamas.
Over the next 15 years, satellite providers and mobile operators built out their constellations and networks — a horse race that cellular won.
“One of the main problems with Iridium’s offering was that terrestrial cellular had spread faster than the company had originally expected,” according to a Tuck School of Business paper. “In the end, cellular was available. . . . [It] spread to cover the overwhelming majority of Europe and even migrated to developing countries such as China and Brazil.”
Today, however, the relationship between cellular and satellite has evolved from adversaries to synergies. The service providers, vendors, standards bodies and investors in both ecosystems recognize that they’re stronger together when it comes to goals such as bridging the Digital Divide and enabling new consumer and business applications.
“As of 2023, in the US 99.6% of the population is covered by mobile wireless, while only 84% of the land geography is covered,” a 5G Americas white paper says. “In Canada about 99.9% of the 40 Million population is covered by mobile wireless service, however that only represented about 30% of the land mass.”
Satellite-based Non-Terrestrial Networks (NTNs) — which can be low Earth (LEO), medium Earth (MEO) or geostationary orbiting (GEO) — are a viable way to fill those gaps in rural communities and remote areas such as oil fields. One reason is because NTNs are more cost effective than building out backhaul and base stations in areas where the population density isn’t sufficient to support those investments.
NTN also can cover areas where it’s difficult or impossible to build cellular infrastructure, such as the roughly 70% of the Earth’s surface that is oceans and seas. This creates opportunities for IoT applications such as using 5G and NTN to seamlessly track intermodal containers filled with high-value goods as they travel by truck to cargo ship to rail and back to truck.
Partnerships and Standards Work Drive Market Momentum
These are just a few examples why the GSMA says NTN-mobile market is on track to reach $28 billion by 2030. Not surprisingly, many major mobile operators now have partnerships with NTN providers, such as T-Mobile and Starlink.
On the technology side, mobile operators also are facilitating NTN partnerships and interoperability through standards bodies. For example, NTNs were initially defined in 3GPP Release 17. A more recent example is 3GPP’s introduction of a Work Item for Release 19 to simplify the use of cellular protocols for managing satellite communication. Two potential benefits are reduced costs and more opportunities for addressable devices.
Antenna Choices and Integration are Key to Success
Antennas play a key role in enabling cellular-NTN synergy. One reason is because many of their bands are close enough that a single antenna can cover both. In fact, that’s why modules that support both cellular and satellite have a single RF connector for the antenna.
As a result, it’s critical to choose a wideband antenna capable of meeting the application’s unique performance and form factor requirements for both technologies. For example, each mobile operator has its own set of total radiated power (TRP) and total isotropic sensitivity (TIS) requirements that the module and antenna must meet in order to be certified. (For more information about how the carrier certification and pre-certification processes work, click here.)
Meanwhile, the NTN application will have its own set of requirements such as axial ratio, gain and efficiency. It also will need to meet the satellite operator’s performance requirements.
Finally, the wideband antenna must be carefully integrated to ensure that device form factor aspects such as the case’s materials and size don’t undermine performance.
