Going Beyond 3GPP with Skylo Standards Plus

Skylo’s NTN is grounded in 3GPP specifications, but much of the development of that network operates on what Skylo refers to as the “Standards Plus” approach. Skylo’s engineers layer in additional technical specifications to improve the functionality, interoperability, and ubiquity of the satellite-based network on top of the 3GPP standards.

Created with a noble mission to ensure technological harmony, the 3GPP blueprint orchestrates a uniformity across access modes, protocols, and network interfaces, equipping the telecom space with interoperability and standards. The 3GPP technical specifications, created in December 1998, have become the global standard for the development of mobile telecommunications networks and equipment. 

Mobile data connectivity has and will continue to have a tremendously positive impact on the economy and our global society. Abiding by the specifications outlined in 3GPP, networks and devices are able to “speak” or interoperate with each other more seamlessly, amplifying this impact.  

In May 2022, the 3GPP ratified their latest release - Release 17. This new release sets the framework for non-terrestrial network (NTN) communications. NTN is synonymous with ‘space-based’ or ‘satellite networks’, but also includes high-altitude platforms within our atmosphere. For those NTNs that are designed to support public networks and the 4G and 5G mobile ecosystems, their technology must incorporate 3GPP standards in order to enable interoperability.

Skylo’s non-terrestrial network (NTN) is grounded in 3GPP specifications, but much of the development of our network operates on what Skylo refers to as the “Standards Plus” approach. Skylo’s engineers additional technical specifications to improve the functionality, interoperability, and ubiquity of the satellite-based network over and above the 3GPP standards.


Skylo Standards Plus

Skylo Standards Plus are foundational for an exceptional user experience. Think about scenarios that users are bound to run into, such as switching between cellular and satellite, texting over satellite, or maintaining a highly available network in case of widespread emergencies such as earthquakes.  Specifically, our Standards Plus approach: 

  1. Establishes reliable connectivity over satellite. Skylo certified devices connect as easily to satellite as over terrestrial, with the same reliability in sending and receiving of messages using the lowest latency possible.
  2. Makes efficient use of scarce satellite spectrum. Skylo Standards Plus reduces overhead, and  increases efficiency without degrading the individual users’ experience.  In order to efficiently utilize the satellite network resources, Skylo’s network scheduling algorithm can schedule delay-tolerant traffic, prioritizing high-importance traffic, such as Emergency Messaging. Skylo has implemented a Class of Service (COS) to ensure that emergency chat messages are prioritized across layers. 
  3. Provide unique, NTN-only applications to deliver an invaluable user experience.  Users have become dependent on cellular connectivity and the functionality that simplifies their lives. Skylo Standards Plus includes additional functionality and features to further augment the services they already receive with terrestrial, increase network usage, and deliver an enhanced user experience. One of the examples of this is roaming capabilities across networks while ensuring network efficiency. For devices supporting emergency use cases, this includes Skylo Class of service for end to end prioritization.

Software Vertical Integration

Skylo Standards Plus leverages complete vertical integration to achieve its objectives across the modem/chipset, the device (your smartphone, wearable, or IoT device), Skylo’s Base Station, the Skylo Network Core, and network/user applications (see the figure below).

By having full management of the end-to-end network stack and components, Skylo can deliver unique capabilities that would otherwise be unattainable. Skylo’s engineers collaborate with chipset and core partners to ensure the implementation and integration of Skylo Standards Plus features into their respective elements of the end-to-end communications tech stack.

Skylo implements a Certification Program that provides the Skylo Standards Plus specifications and requirements to partners to follow with their specific devices. Once these standards have been implemented, Skylo reviews and tests the third-party devices on our network to ensure that they are compatible with both the 3GPP standards and Skylo’s Standards Plus requirements. This certification assures that the devices are able to connect seamlessly with Skylo NTN and take advantage of all the benefits in user experience, reliability and capacity that our network provides. To learn more about this program, click here.

A Case for Standards Plus: Multicast

Multicast is a way to distribute a single message or copy of data to a group of users (one-to-many). It has numerous benefits, including:

  • Lower bandwidth requirements - Multicast sends only one stream of data rather than multiple streams, resulting in reduced network congestion and improved overall network efficiency.
  • Efficient bandwidth usage - The bandwidth usage remains the same regardless of the number of recipients on the network, ensuring consistent and fast data transmission speeds for all users.
  • Improved Quality of Experience - With multicast, users receive data simultaneously, ensuring a consistent and synchronized experience across the recipient group.

When multicasting over satellite, the benefits are even more acute, making multicast a perfect fit for  NTN. A key advantage of supporting multicast with a satellite network rather than a terrestrial network is the NTN coverage footprint. For instance, the coverage area of a single beam from a satellite can vary from the size of one United States’ state to several states, all supported by one base station, whereas cellular tower coverage is typically 2 - 5 miles in radius. 

Skylo has designed its multicast protocol to fully leverage the satellite network capacity and enhance the user experience. With the help of Skylo’s multicast protocol, devices across the area serviced by a base station can receive transmitted multicast messages using the existing radio interface. 

Use cases for multicast include: 

  • Alerts and warnings
  • Group messages
  • Application/vendor specific announcements
  • Device configuration updates including FOTA and software updates

Skylo’s multicast service includes two highly optimized flows. The first one defines physical and radio control flow for multicast messages (NB-IoT) and the second one defines multicast protocol used for multicast service subscriptions by the devices (application layer). To learn more, please reach out to us here

Envisioning NTN Support in Real-World Disaster Scenarios

On February 6, 2023, a 7.8 magnitude earthquake struck southeast Turkey, leveling many buildings and leaving its population without basic necessities, such as shelter, food, sanitation, and even water.  The entire infrastructure was taken down during the massive earthquake, meaning that all methods of communication were damaged. Cell towers fell down, inhibiting the ability of rescuers to communicate with those that needed to be rescued. 

Should NTN have been an available service in that area, it could have been used by emergency response teams as a reliable way to connect with each other, letting everyone know where help was needed. The ability to use personal devices in times of crisis to find those affected or seek support is a critical component of ensuring that as many people as possible survive catastrophic events. 


In another example, in 2022, forest fires ravaged parts of Northern California, including Yosemite National Park. Because of the mountainous terrain of Yosemite, visitors often have poor cellular experience as cell tower signals are blocked. When the fires broke out, visitors needed to be evacuated quickly, particularly because the roads coming in and out of the park are limited and would become constrained. Evacuation orders were not reliably being transmitted to those in the vicinity because of the lack of cellular coverage, requiring them to be issued by word of mouth. 


NTN would have made a significant difference in this scenario. Enabling emergency personnel to send evacuation Instructions or status of the wildfires to the thousands of visitors would have eased minds and reduced the ensuing panic. 

Experience, Learn, and Innovate

In order to achieve continuous technological excellence, our internal mantra is to experience, learn, and innovate. Without experimenting and trial and error, we cannot learn, so this is an inherent part of our development cycle. Not only do we lab test our technology, but we also field test it with multiple satellites to ensure seamless interoperability and ease of use. This continuous experimentation enables our engineers to better test what is working and what is not, how to solve for unanticipated problems, and to optimize the network to deliver the highest quality user experience available that addresses the unique applications that NTN supports. 

Our knowledge and learnings are further enhanced through direct interaction and conversations with our partners and customers regarding the practical issues that they are facing and that the existing standards could not fully resolve. In order to deliver the best NTN experience possible, we designed Standards Plus to include specifications that would address the challenges our customers and partners were facing. 

The mantra is apparent in our Standards Plus approach, which builds on 3GPP specifications and includes additional enhanced technical features  designed to address the unique challenges and opportunities presented by NTN. To learn more about the standards and certifying devices through our program, please reach out to our team

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