What are Non-terrestrial Networks (NTNs)?

Non-Terrestrial Networks (NTNs) are advanced wireless communication systems that operate above the Earth's surface using satellites, high-altitude platform stations (HAPS), and drones. Unlike traditional terrestrial networks that rely on ground-based infrastructure, NTNs leverage spaceborne and airborne assets to provide connectivity, especially in remote and underserved areas. They play a crucial role in enhancing global communication coverage and are integral to the 5G and future 6G ecosystems, supporting a wide range of applications from internet access to critical communications. 

The need for Non-Terrestrial Networks (NTNs) arose from the limitations of traditional terrestrial infrastructure, which struggles to provide coverage in remote or underserved regions and can fail during natural disasters. NTNs offer a solution by extending connectivity to these areas and providing a backup in emergencies. They also address the growing demand for global coverage driven by technologies like IoT and 5G. Additionally, NTNs can be more cost-effective than extensive terrestrial networks and serve strategic and scientific purposes. Advances in satellite and high-altitude platform technology have made NTNs more viable, enabling them to complement and enhance terrestrial networks. 

How does an NTN operate? 

NTNs function by establishing communication links between user equipment on the ground and non-terrestrial platforms like Satellites, HAPS and Drones: 

Satellites: Operating in various orbits - Low Earth Orbit (LEO), Medium Earth Orbit (MEO), and Geostationary Orbit (GEO) - satellites provide coverage over large areas. LEO satellites, positioned around 180 to 2,000 km above Earth, offer low-latency communication but require a constellation of satellites for continuous coverage. MEO satellites, at approximately 2,000 to 20,000 km, balance coverage and latency, while GEO satellites, at around 36,000 km, provide global coverage with higher latency. 

High-Altitude Platform Stations (HAPS): Airborne platforms such as balloons, airships, and unmanned aerial vehicles (UAVs) that operate at altitudes of 20 to 50 km. HAPS can serve as mobile base stations, providing persistent coverage over specific areas, ideal for disaster recovery and remote broadband connectivity. Click here to learn more about HAPS.

Drones: Used for various communication tasks, drones can act as temporary relay stations or mobile communication hubs in areas with compromised infrastructure. 

These platforms communicate with ground stations and user devices through radio frequency (RF) links and optical links (optical communication links employ lasers for transmitting information). The communication involves tracking satellites, managing signal handoffs, and ensuring seamless connectivity across different platforms.  

NTNs involve dynamic tracking of moving satellites, especially in Low Earth Orbit (LEO) constellations. Ground stations and user devices must continuously track the position of satellites to maintain a stable connection. Phased Array Antennas are advanced antennas that can electronically steer their beams to follow satellites across the sky, facilitating seamless communication without mechanical movement. As satellites move, particularly in LEO, there is a need for seamless handoff of signals between satellites to ensure uninterrupted service. This is managed through sophisticated network protocols that handle the transition smoothly. Ground stations and HAPS serve as multiple access points, ensuring that even if one satellite moves out of range, another can take over the communication link. 

NTNs form hybrid networks by integrating with terrestrial communication infrastructure. This hybrid approach enhances overall network coverage and reliability. 

What are the applications of NTNs?

Non-Terrestrial Networks (NTNs) have a wide array of applications across various industries and use cases. In remote and underserved regions, NTNs provide essential connectivity for broadband access, bridging the digital divide and enabling access to education, healthcare, and economic opportunities. They enhance precision agriculture by facilitating real-time data collection and monitoring, which improves resource management and crop yields. In emergency situations, NTNs offer critical backup communication channels, supporting disaster response and recovery efforts. NTNs also play a significant role in maritime and airborne communications, improving safety and operational efficiency for ships and aircraft. Furthermore, they support connected vehicles by enabling real-time traffic updates and advanced safety features. Their role in expanding Internet of Things (IoT) connectivity allows for global asset tracking and environmental monitoring, making them crucial for a wide range of technological advancements and services.

What are the different types of NTNs? 

Non-Terrestrial Networks (NTNs) encompass several types of systems, each serving distinct functions and providing unique benefits: 

Air-to-Ground (ATG) Networks: These networks provide internet access and communication services to aircraft using ground stations equipped with antennas aimed at the sky. This setup ensures high-speed data transmission to and from aircraft during flight. Although ATGs are fundamentally different from satellite-based NTNs, they are included in the NTN category due to their non-terrestrial nature. Like other NTNs, ATGs help extend network coverage beyond traditional terrestrial infrastructures. 

Non-Terrestrial Network - Internet of Things (NTN-IoT): NTN-IoT extends the reach of IoT applications, enabling connectivity for devices in remote, maritime, and aerial locations. It typically operates at GEO and LEO altitudes, focusing on low power consumption and efficient communication protocols.

Non-Terrestrial Network – 5G New Radio (NTN-5G-NR): 5G-NR NTN solutions integrates satellite-based services with 5G devices, operating mainly in LEO. It supports higher data rates and bandwidth, facilitating direct communication for smartphones, tablets, and other mobile devices. Click here to learn more about 5G-NR NTN.

Non-Terrestrial Networks (NTNs) represent a significant advancement in global communication technology, bridging the connectivity gap left by traditional terrestrial systems. By leveraging various platforms such as satellites, high-altitude balloons, and drones, NTNs provide unparalleled global coverage, particularly in remote and underserved regions. They play a crucial role in expanding internet access, supporting critical applications like precision agriculture, emergency communications, and maritime operations, and facilitating the growth of technologies such as IoT and 5G.

NTNs differ fundamentally from terrestrial systems in their operational altitude and coverage capabilities. They use a mix of radio frequency and optical links to communicate with ground stations and user devices, ensuring seamless connectivity across diverse platforms. The integration of LEO, MEO, and GEO satellites, along with HAPS and air-to-ground networks, creates a hybrid network that enhances global communication infrastructure.

The growing need for NTNs arises from the limitations of terrestrial networks, particularly in reaching remote areas and providing reliable coverage in challenging environments. As the demand for ubiquitous connectivity increases, NTNs will continue to play a pivotal role in overcoming these challenges and driving the future of global telecommunications.