D2D satellite applications: How 5G NTN bridges the gap for satellite operators

5G NTN is helping transform satellite connectivity from a niche capability into a scalable, revenue generating extension of terrestrial networks, with the potential to support service continuity between satellite and terrestrial coverage. At the heart of this evolution is Direct-to-Device satellite (D2D) communication, which is rapidly gaining global traction, unevenly though.

While 5G NTN is the underlying technology or architecture (based on the 3GPP standardized framework) that enables satellites to function as part of the 5G radio access network, D2D is just one specific application powered by this technology. Let us explore D2D in detail.

There are two paths to D2D, both aiming to close coverage gaps:

• Short-term: unmodified 4G
  This approach uses existing terrestrial 4G frequencies and device stacks with minimal changes. It offers faster time-to-market and leverages a widespread 4G device base.
  However, coverage typically ends at country borders since terrestrial frequencies are (re)used across markets.
    
• Long-term: 5G NTN
  This is a future-proof NTN approach, as specified in the 3GPP Release 17 and beyond, based on 5G Standalone (SA) using spectrum allocated for satellite operations. It’s borderless by design and supports richer services along with more reliable session management. However, device adoption is lower than unmodified 4G, and not all terrestrial network operators have rolled out 5G SA yet. 

In the remainder of this article, we abstract away from the unmodified 4G approach and focus instead on the 5G NTN approach. The end goals are the same, widespread coverage and service continuity, but 5G NTN is more advanced and optimized for NTN usage. 

With 3GPP Release 17, NR-NTN specifications enabled direct communication between satellite access networks and compatible handheld devices. Supporting devices require an NTN-capable modem or chipset, and RF front-end components that support the relevant NTN frequency bands.

By adapting 5G New Radio (NR), Narrowband IoT (NB-IoT), and Long-Term Evolution for machine-type communications (LTE-M), NTNs have enabled D2D satellite connectivity and IoT satellite connectivity, extending coverage to previously unreachable areas to deliver network reach globally.

Under the D2D satellite connectivity, a satellite operator partners with a mobile operator to provide direct connectivity services to mobile devices present in those regions which are not covered by terrestrial carriers. Without building new infrastructure, Direct-to-Device closes the coverage gap by extending mobile phone connectivity to remote, unreachable areas such as oceans, deserts, mountains, rural regions, airplanes, and ships.

Besides providing coverage where terrestrial networks are economically unviable, operators can even venture into new addressable segments, including IoT, maritime, and mobility, and offer resilience in case of outages or crises. This convergence between space and ground is a big opportunity to bridge the digital divide.

In the 5G NTN approach, the device must determine its position first via the Global Navigation Satellite System (GNSS) before attaching to the satellite network. This is not the case in unmodified 4G, so there is no guarantee of obtaining a device’s precise location here. Because 5G NTN can reliably establish device location and optimize the link accordingly, it enables more advanced and optimized NTN use cases.

NTN-5G enhanced coverage benefits consumers, industries, and governments through:

• D2D remote area connectivity: NTN enables communication services to mobile users via satellite connectivity in unreachable, remote locations not serviced by terrestrial networks.
  
• Disaster recovery: By re-establishing communications in disaster-affected areas or during emergencies, NTN provides extended mobile coverage through reliable text message or alerting.
  
• Maritime and aviation: NTN supports passenger connectivity via low-bandwidth text messages or emergency alerts, as well as onboard infotainment such as movies, games, music etc.
  
• Automotive: NTN enables automatic vehicle crash notifications, shares location data and distress signals from remote areas where terrestrial networks aren’t available. It also supports vehicle performance monitoring and location tracking through compatible connected vehicle solutions and applications.
• Critical infrastructure: NTN ensures continuous oversight across power grids, energy infrastructure, and remote stations.

In addition, 5G-Advanced standardization and development are continuing across successive 3GPP releases focusing on deployment readiness and enhancements across AI/ML, energy efficiency, sustainability, satellite, NR mobility and coverage, public safety, and communications.

To summarize, the existing applications of 5G NTN, combined with the ongoing developments in 3GPP standardization and growing terrestrial network-satellite operator partnerships, are accelerating the adoption of 5G NTN and shaping global connectivity.

Only if satellite operators behave like any other network partner, can D2D unlock its true potential. What this means is going beyond emergency communications and basic text messaging to support wider applications like voice and data making satellite connectivity a richer experience for mobile subscribers. A technical integration model around roaming can simplify things heavily for D2D. Treating the satellite operator as a visited network within the 3GPP roaming framework can bring standardized interfaces, proven security, settlement and testing from day one.

The bottom line is to integrate D2D in the mobile experience, bringing in seamless switching among networks (like Wi-Fi, cellular, or satellite), extended service support (with voice and data), and automatic access assistance (becoming a mobile subscription standard).  

Despite their capabilities, satellite technology is not inherently equipped with global roaming. This is because:

• Direct integration with a terrestrial network is complex and difficult to scale across multiple integrations.
• Satellite operators need to set up roaming agreements with terrestrial networks one by one. 
• NTN as a full retail offering remains limited to a specific market; most use cases require hybrid non-terrestrial network/terrestrial network solutions.

To enable direct-to-cell or satellite IoT connectivity, satellite networks must integrate with terrestrial mobile operators. However, this needs a complex telco-grade backend to handle roaming agreements, traffic routing, and billing.

Here are four key telecommunication components to enable roaming for satellite operators:

• A managed roaming service that helps establish multiple roaming agreements in a shorter period of time.
  
• Business intelligence and device behavior analytics that offer satellite operators and terrestrial networks greater visibility into network and device activity.
  
• Financial and technical settlement processes that include GSMA-aligned procedures to track data usage and help ensure correct billing for terrestrial networks.
  
• 5G IoT hybrid connectivity devices that require a SIM & management platform for satellite operators willing to manage their own device fleet.

Satellite operators can tap into the existing multi-billion subscriber base of terrestrial networks by positioning themselves as space-based roaming cell towers to leverage this huge monetization opportunity and share this revenue.

Book a meeting with us today to find out how you can focus on satellite connectivity while we manage the telco complexities, helping you accelerate and scale. 

The real opportunity for 5G NTN lies not just in coverage, but in faster and less complex integration and interoperability, enabling satellite operators to function as efficient roaming partners within global terrestrial networks. The goal is an uninterrupted network and a trusted experience, anywhere in the world, where the user never knows which network they are on because the quality, security, and reliability are the same either way. The industry already has the framework for connecting networks at global scale. Satellite operators do not need a new one – they need the right partner to scale fast. 

For satellite operators, the competitive advantage lies in how quickly and effectively they can integrate with established roaming infrastructure, ensure security and compliance, and deliver consistent service quality. With the right partnerships and technology foundation, 5G NTN can unlock new business models, expand market reach, and position satellites as a critical pillar of future connectivity.

BICS plays a key role in this transition by bridging the gap between satellite and terrestrial networks, helping terrestrial mobile operators access multi-constellation satellite operators faster and in a less complex way, thereby turning technical capability into commercial success for them.

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