5G Non-Terrestrial Networks (NTN)

Non-Terrestrial Networks (NTN) are networks or segments of networks that use airborne or spaceborne vehicles for transmission. These networks use satellites, drones, and other airborne vehicles to provide connectivity wirelessly to even the most remote areas on Earth. This technology has the potential to revolutionize many industries, from agriculture to shipping, by providing reliable, high-speed connectivity to previously unreachable areas.

5G telecommunication systems need to be able to deliver services anywhere and anytime. NTN systems can help satisfy this need for anywhere and anytime connectivity by offering wider area coverage and ensuring service availability, continuity, and scalability.

3GPP’s 5G standards recognize NTNs as a part of the 5G connectivity infrastructure. Airborne or spaceborne 5G base stations can be launched and connected to terrestrial ground stations in a commercially feasible way. These high-altitude network segments maximize the inherent value of 5G networks by solving coverage problems and difficult use cases that ground-based infrastructure alone cannot address. Radio technologies like beamforming and 5G numerology can even be used to support a reliable connection directly from mobile devices to stations at high altitudes.

Satellites have always been used in mobile networks but are mainly limited to supplying backhaul for access networks typically in rural and remote areas. But in NTNs, satellites can be used not just for backhaul but also for access networks. Initially, only satellites were added as potential NTNs to 5G standards. Later, it was felt that NTN’s scope and commercial scalability can be expanded even more by including airborne vehicles typically operating in altitudes between 8 and 50 km.

There are broadly two types of vehicles used in NTN infrastructure:

Spaceborne vehicles: Satellites including Low Earth Orbiting (LEO) satellites, Medium Earth Orbiting (MEO) satellites, Geostationary Earth Orbiting (GEO) satellites as well as Highly Elliptical Orbiting (HEO) satellites.

Airborne vehicles: High Altitude Platforms (HAPs) that include Unmanned Aircraft Systems (UAS), Lighter than Air UAS (LTA), Heavier than Air UAS (HTA), all operating in altitudes typically between 8 and 50 km, quasi-stationary.

Advantages of 5G NTNs

There are several key benefits of 5G NTN technology:

• One of the most significant advantages is that it offers much wider coverage than traditional terrestrial networks. Since the NTN network operates from a high altitude, it can cover a vast area without the need for large numbers of ground-based infrastructure. This makes 5G NTN networks a reliable way to provide connectivity to remote and rural areas, where traditional infrastructure is not practical.
• Another advantage of 5G NTN technology is its high-speed data transfer capabilities. With speeds of up to 20 Gbps, 5G NTN networks can handle large amounts of data quickly and efficiently. This makes them ideal for applications that require real-time data processing, such as remote monitoring, surveillance, and autonomous vehicles.

Disadvantages of 5G NTNs

Despite its many advantages, there are also some challenges associated with 5G NTN technology:

• One of the main obstacles is the cost of deployment. Building and launching satellites and other airborne vehicles is a costly undertaking, and it may take some time for these costs to be recouped through revenue generated by the network.
• Another disadvantage of 5G NTN technology is its unreliability compared to traditional terrestrial networks. Since the network operates wirelessly from a high altitude, it is susceptible to interference from terrain, weather, and other factors that can disrupt wireless networks. This means that 5G NTN networks may be unable to provide connectivity in harsh environments. Another factor that can impact 5G NTN performance is atmospheric attenuation. This occurs when the signal passes through the atmosphere, which can cause the signal to weaken or become distorted. This can happen due to a variety of atmospheric factors, including humidity, temperature, and pressure.
• There are also concerns about the security and privacy of 5G NTN networks. Since the network operates from a high altitude, it is difficult to monitor and secure. This has raised concerns about the potential for cyberattacks and other security breaches.

Use Cases for NTN

NTNs can be vital for both 5G enhanced mobile broadband (eMBB) as well as massive machine type communications (mMTC). They are expected to be beneficial in the following use cases:

• Rural fixed broadband at home and enterprise
• Rural mobile broadband
• Mobile broadband to passengers in vehicles, vessels or aircraft
• Enhanced data rates in conjunction with terrestrial networks using technologies like Access Traffic Steering, Switching and Splitting (ATSSS)
• Network resilience for public safety or other critical links
• Rural and remote IoT that can be connected via IoT gateways, backhauled via NTN
• Freight tracking across countries, regions and oceans

3GPP standards are still exploring Satellites and NTN in detail for complementing terrestrial 5G. 5G NTN technology holds enormous promise for a wide range of applications. From providing internet access to rural communities to enabling remote monitoring and surveillance, this technology has the potential to transform many industries. With many different LEO mega-constellations planned in the coming years, having a standard in place can provide a means to have standards-based global connectivity.

This kind of continuity could be very useful for IoT devices used in asset tracking, logistics etc. applications. Other types of devices like smartphones or connected cars could also take advantage of NTN where no terrestrial coverage is available. As technology continues to advance, it is likely that we will see more widespread deployment of 5G NTN networks in the coming years. 5G has the potential to enable truly global connectivity using NTNs.