Satellite direct-to-device services

Introduction

Advancements in satellite-based connectivity have created opportunities for policymakers to address connectivity challenges, particularly in remote or underserved areas. One such innovation is satellite direct-to-device (D2D) communication, enabling direct interaction between satellites and end-user devices such as smartphones. This can be achieved through two primary approaches: utilizing frequency spectrum allocated to the mobile-satellite service (MSS) or frequency spectrum allocated to the land mobile service (LMS), the latter, in particular by the use of the spectrum identified for terrestrial International Mobile Telecommunications (IMT).

These technologies are designed to bridge connectivity gaps in urban, suburban, and remote areas, including maritime, aeronautical, desert, and mountainous regions. The successful deployment of D2D technologies depends on establishing robust policy, regulatory, and economic frameworks. Key considerations include spectrum allocation, interoperability, interference management, and international coordination. This article examines the current landscape of D2D services, explores relevant technological and regulatory considerations, and discusses emerging policy responses worldwide.

Business models and technological considerations

D2D connectivity services employ diverse approaches depending on the satellite constellations and spectrum utilized. Providers operate geostationary Earth orbit (GEO), medium Earth orbit (MEO), and low Earth orbit (LEO) constellations, each offering varying latency, coverage, and cost profiles. These constellations are categorized into geostationary orbit (GSO) and non-geostationary orbit (non-GSO) satellites.

Source: TMG.

GSOs in D2D Services

Several providers leverage GSO satellite infrastructure, such as Viasat/Inmarsat, utilizing MSS spectrum to deliver services directly to end-user devices, initially for data applications. Another example is Skylo, which connects narrowband Internet of Things (NB-IoT) devices to partner satellites, offering supplemental coverage for terrestrial networks without requiring additional hardware.

Non-GSOs in D2D Services

Non-GSO providers, such as Starlink, AST SpaceMobile, and Lynk Global, utilize LEO and MEO satellite constellations to deliver connectivity in partnership with mobile network operators (MNOs). These models provide various services, including text, voice, data, and IoT applications, demonstrating the potential to address coverage gaps in remote areas. Some examples of existing initiatives include:

• Starlink has been investing in broadband connectivity through fixed connections, and more recently is using its satellites to partner with MNOs including T-Mobile, Optus, and KDDI with the aim to provide text, voice, data, and IoT services to mobile devices, such as smartphones and devices.^[1]
• AST SpaceMobile‘s LEO satellites, once operational, will use terrestrial spectrum from MNOs such as AT&T, Rakuten, Vodafone, and others to provide D2D connectivity. The company plans to work with MNOs to offer supplemental coverage through day passes, monthly subscriptions, and emergency connectivity services.^[2]
• Lynk Global has partnered with PNCC, Palau’s MNO, to provide D2D texting services for residents across Palau’s remote islands. The partnership has enabled users to send and receive texts during three satellite overpasses per day, and Lynk and PNCC have plans to continue expanding availability and services for customers who previously relied on VHF radios for communication (Lynk 2023).^[3]

As described, there are various approaches to providing D2D services that utilize different forms of spectrum, hardware, and partnerships, making it essential for regulators to take into account specific technological needs and trends when creating a D2D regulatory regime.

Spectrum management

Effective spectrum management is crucial to promoting the proliferation of D2D services and ensuring that society benefits from its applications. As such, regulators must consider the dynamic spectrum needs of D2D operators, as well as the need to effectively allocate spectrum in a way that minimizes interference, accounts for existing license holders and incumbent users, and promotes innovation.

D2D services, depending on design, will use either MSS or LMS frequency spectrum, including IMT, to send and receive signals from a connected satellite. Both spectrum allocations can enable advanced use cases such as data, voice, and IoT communication, but each approach presents a unique set of considerations. As such, the whole D2D ecosystem (terrestrial and satellite) needs to be considered when assessing current and future spectrum allocations.^[4]

D2D in MSS frequency bands: This variant leverages MSS frequency spectrum, such as the L and the S bands, utilizing established standards for seamless integration of satellite and terrestrial networks. MSS-based D2D services offer high-quality voice, data, and IoT communication without requiring additional regulatory frameworks in many countries. Supported devices include smartphones, IoT devices, and wearables, benefiting from MSS capabilities that ensure minimal interference due to well-defined spectrum allocations​.

D2D in LMS frequency bands: This approach enables satellites to use LMS frequency spectrum to complement terrestrial mobile networks, addressing connectivity gaps in areas where terrestrial infrastructure is unavailable. This model requires partnerships between satellite operators and MNOs for spectrum sharing. Updated regulatory frameworks must address interference management and power limitations, as these frequency bands are traditionally allocated for terrestrial services​​.

International efforts to open spectrum for D2D

Given the cross-border nature of satellite services, international collaboration is essential. ITU is giving due consideration to this matter and studies are ongoing under WRC-27 agenda item 1.13^[5] for potential MSS allocations to complement terrestrial IMT networks. In addition, WRC-27 agenda items 1.12^[6] and 1.14^[7] are considering additional MSS traditional allocations. National policies should be with global standards to foster D2D ecosystem growth while mitigating interference concerns.

WRC-27 agenda items 1.12, 1.13 and 1.14 studies are considering possible frequency spectrum allocations that could foster the proliferation of D2D services.

The forthcoming WRC-27 will play a pivotal role in shaping the future of D2D technologies by addressing key regulatory and technical challenges, paving the way for ubiquitous and seamless global connectivity​.

Interoperability

The integration of satellite D2D services with terrestrial mobile networks has been advanced by the 3rd Generation Partnership Project (3GPP) Release 17 standards.^[8] 3GPP is an international collaborative body that unites various standard development organizations to create and maintain technical specifications for mobile communications. These standards establish a unified framework for the interoperability of non-terrestrial networks (NTNs) and terrestrial networks, addressing the growing demand for seamless global connectivity.

Release 17 is a pivotal milestone in enabling the full integration of satellites within the 3GPP ecosystem, laying the foundation for a global standard that supports future satellite networks. By defining precise technical specifications, this release ensures compatibility between NTNs and terrestrial systems, allowing D2D providers to use frequency spectrum in bands defined as n255 (1 626.5-1 660.5 MHz and 1 525-1 559 MHz for uplink and downlink, respectively) and as n256 (1 980-2 010 MHz and 2 170-2 200 MHz for uplink and downlink, respectively). ^[9] This compatibility eliminates the need for specialized hardware in end-user compatible devices, facilitating cost-effective and widespread adoption.

The adoption of these standards benefits both users and operators. For users, it enables seamless communication across NTNs and terrestrial networks, providing uninterrupted connectivity regardless of location, from urban centers to remote or underserved areas. For operators, it fosters interoperability and promotes economies of scale, as equipment manufacturers and network providers can align their offerings to standardized specifications.

International standards such as 3GPP Release 17 play a critical role in driving global harmonization and reducing fragmentation in D2D services. By ensuring that devices and networks adhere to a common framework, these standards enhance interoperability, minimize interference risks, and accelerate the deployment of integrated satellite-terrestrial ecosystems. As a result, 3GPP’s ongoing efforts to refine NTN standards, in conjunction with ITU-R identification of necessary frequency spectrum, continue to be instrumental in shaping the future of global connectivity and bridging digital divides.

Policy response to D2D

Given the wide array of technical considerations associated with D2D connectivity, it is important that regulators start considering measures to foster a robust, interference-free, and complementary ecosystem. Further, as D2D solutions continue to be announced and operationalized, the market for D2D connectivity is expected to rapidly expand over the next years, with the projected revenue from satellite D2D services, 2022-2032, shown in the figure below.

Source: NSR.

Policymakers should actively develop and implement comprehensive national regulatory frameworks tailored to D2D services while closely monitoring global developments, particularly those spearheaded by the ITU and other international bodies. This proactive approach will ensure alignment with international standards, address cross-border challenges, and foster innovation in the rapidly evolving D2D ecosystem.

To support this endeavor, this section examines innovative regulatory frameworks already implemented or under consideration in various countries. By highlighting best practices, it aims to provide actionable insights for regulators to craft effective policies that facilitate the efficient use of spectrum, promote interoperability, and address technical and operational challenges associated with D2D technologies. These frameworks serve as a roadmap for fostering a resilient and sustainable D2D ecosystem that bridges connectivity gaps globally.

National D2D regulatory initiatives

Several countries have initiated or implemented regulatory frameworks to support satellite D2D services. These initiatives, while varying in scope and focus, offer valuable examples of mechanisms that regulators can adapt to develop national frameworks for D2D technologies. Below is an overview of key national regulatory efforts.

United States

The United States Federal Communications Commission (FCC) was the first regulatory body to adopt a comprehensive framework for integrating satellite-based connectivity with terrestrial mobile networks. In March 2024, the FCC issued its “Supplemental Coverage from Space” (SCS) order to expand coverage for communication and emergency services. The framework prioritizes maintaining terrestrial network quality, protecting existing spectrum rights, and minimizing interference. It designates specific frequency bands for SCS, including the 600 MHz, 700 MHz, 800 MHz, Broadband PCS, and AWS-H Block. Additionally, the FCC’s framework identifies new frequency bands for MSS allocations to support D2D services that do not rely on IMT spectrum.^[10] This regulatory model exemplifies how to foster innovation, promote efficient spectrum management, and enable partnerships between D2D operators and MNOs without requiring separate satellite spectrum licenses.

Brazil

In April 2024, Brazil’s National Telecommunications Agency (ANATEL) introduced a regulatory sandbox to facilitate D2D trials. This sandbox allows operators and MNOs to test D2D services in the 800 MHz band within a controlled environment. By doing so, ANATEL supports innovation and efficiency while addressing key challenges such as interference and interoperability.^[11] This approach serves as a flexible mechanism for testing and refining D2D services before broader implementation, ensuring that regulatory frameworks evolve in alignment with technical and operational realities.

Australia

The Australian Communications and Media Authority (ACMA) published a regulatory guide for D2D services in September 2024 following stakeholder consultations. This guide identifies the 700 MHz, 800 MHz, 850/900 MHz, and 2.5 GHz bands as suitable for IMT-based D2D services. ACMA’s regulatory framework provides clarity on spectrum use for both MSS and IMT services, emphasizing the need for coexistence and addressing interference issues.^[12] The Australian approach highlights how thorough consultation can lead to practical guidelines for D2D integration.

Canada

In October 2024, Canada’s Innovation, Science, and Economic Development (ISED) completed a consultation on a policy, licensing, and technical framework for supplemental mobile coverage by satellite. The proposed framework identifies multiple frequency bands, including the 600 MHz, 700 MHz, 800 MHz cellular, AWS-1, AWS-3, and PCS bands, for potential D2D applications.^[13]

In February 2025, ISED announced the Decision on a Policy, Licensing and Technical Framework for Supplemental Mobile Coverage by Satellite^[14] confirming the objectives of expanding mobile services, fostering investment and competition.

Saudi Arabia

Saudi Arabia’s Communications, Space, and Technology Commission (CST) addressed satellite connectivity in its 2024-2027 Spectrum Outlook. CST identified several spectrum planning initiatives to support the growth of non-terrestrial networks (NTNs) and broader satellite spectrum use.^[15] By integrating spectrum management for NTNs within its strategic planning, Saudi Arabia exemplifies how long-term spectrum outlooks can support D2D technology adoption.

Zambia

In August 2024, Zambia’s Information and Communications Technology Authority (ZICTA) launched a public consultation on a proposed satellite regulatory framework. The consultation emphasizes the use of IMT spectrum between 694 MHz and 2.7 GHz for D2D services in underserved and unserved areas.^[16] Zambia’s initiative, which includes a regulatory sandbox, contributes to ongoing studies under WRC-27 and highlights the potential of D2D technologies to address connectivity gaps in developing countries.

Impact of D2D services

The transformative potential of D2D services spans ubiquitous connectivity, enhanced emergency response, and sector-wide innovation. To unlock these benefits, countries must establish clear regulatory and licensing frameworks, fostering a sustainable and inclusive D2D ecosystem that addresses connectivity gaps and drives technological advancement.

Ubiquitous connectivity

Satellite D2D services, leveraging both MSS and IMT identifications, offer a complementary solution to extend connectivity to remote, underserved, and unserved areas. By enabling direct connections between satellites and mobile devices, D2D systems provide a valuable alternative for areas where traditional terrestrial infrastructure, such as fiber optic cables and cell towers, is challenging or slow to deploy. This approach can work alongside terrestrial networks to address coverage gaps, particularly in rural and remote areas.

Satellite D2D technology presents a new avenue to support the rapid deployment of high-speed, secure connectivity to these communities. It complements terrestrial efforts by offering additional means to reach populations that are otherwise difficult to serve. Moreover, D2D can facilitate universal, continuous connectivity across borders, helping more communities access essential services, maintain communication, and engage in the global economy. By working in tandem with terrestrial networks, D2D has the potential to significantly enhance connectivity for underserved populations worldwide.

Emergency services

In areas without cellular coverage, D2D services also have critical applications for disaster response and emergency communications. In the event of natural disasters damaging terrestrial infrastructure, D2D can serve as a “backstop” to enabled devices and allow users to continue receiving service. One of the most known D2D applications is Apple’s “Emergency SOS via Satellite”, which is operational on the company’s newest smartphones. The D2D service is enabled by Globalstar’s satellites and ground stations and uses MSS frequency spectrum in the L and S bands.^[17]

Source: Apple.

Innovative use cases

The supplemental nature of D2D services to the terrestrial networks offers new opportunities to enhance IoT connectivity across various sectors. Industries such as agriculture, shipping, manufacturing, and public safety can leverage D2D coverage to ensure reliable communication in even the most remote areas. By providing uninterrupted connectivity, D2D services enable applications like environmental monitoring, asset tracking, and precision agriculture, supporting critical operations and driving innovation in traditionally underserved areas.

Key findings

References

1. https://www.starlink.com/business/direct-to-cell ↑
2. https://ast-science.com/spacemobile-network/direct-connection/ ↑
3. https://lynk.world/news/lynk-pncc/ ↑
4. https://gsoasatellite.com/wp-content/uploads/GSOA-D2D-Paper-Aug-24.pdf ↑
5. https://www.itu.int/dms_pub/itu-r/oth/0c/0a/R0C0A0000110013PDFE.pdf ↑
6. https://www.itu.int/dms_pub/itu-r/oth/0c/0a/R0C0A0000110012PDFE.pdf ↑
7. https://www.itu.int/dms_pub/itu-r/oth/0c/0a/R0C0A0000110014PDFE.pdf ↑
8. https://www.3gpp.org/news-events/partner-news/ntn-rel17 ↑
9. https://www.3gpp.org/technologies/ntn-overview ↑
10. https://docs.fcc.gov/public/attachments/FCC-24-28A1.pdf ↑
11. https://www.gov.br/anatel/pt-br/assuntos/noticias/anatel-autoriza-o-inicio-dos-testes-para-direct-to-device-d2d ↑
12. https://www.acma.gov.au/sites/default/files/2024-09/Regulatory%20guide_Operation%20of%20an%20IMT%20satellite%20direct-to-mobile%20service.pdf ↑
13. https://ised-isde.canada.ca/site/spectrum-management-telecommunications/en/learn-more/key-documents/consultations/consultation-policy-licensing-and-technical-framework-supplemental-mobile-coverage-satellite ↑
14. https://ised-isde.canada.ca/site/spectrum-management-telecommunications/en/learn-more/key-documents/consultations/decision-policy-licensing-and-technical-framework-supplemental-mobile-coverage-satellite ↑
15. https://www.cst.gov.sa/en/mediacenter/pressreleases/Pages/2024090901.aspx ↑
16. https://www.zicta.zm:448/api/download-document/public-consultation-on-the-proposed-satellite-regulatory-frameworkdocx ↑
17. https://www.apple.com/newsroom/2022/11/emergency-sos-via-satellite-made-possible-by-450m-apple-investment/ ↑