What Are the Interferences to Radio Waves?
With the rapid development of satellite technology, low earth orbit (LEO) satellites have become a disruptive innovation. Located about 100 to 500 miles above the earth’s surface, these satellites have completely changed the way we communicate, collect data and monitor the earth. LEO satellites play a key role in many fields such as telecommunications, earth observation, scientific research and national security. It is expected that by 2029, the size of commercial constellations will increase from 35% to 70%, of which about 65% of the growth will be concentrated in communication applications, involving satellite networks spanning low earth orbit (LEO), medium earth orbit (MEO) and geosynchronous orbit (GEO) satellites.
- Comparison of different satellite orbits
GEO satellites rotate synchronously with the Earth at the same speed, so their position relative to the Earth is fixed, ensuring a fixed pointing angle from any location on the Earth’s surface. On a mobile platform, ground-based GEO directional antennas must continuously point to a designated GEO satellite. These traditional ground-based satellite antennas are large and expensive, have many moving parts, and require regular maintenance.
MEO satellites, such as GPS, are often used for navigation. MEO satellites have their own advantages, but similar to GEO satellites, they are expensive to launch and maintain. Although GEO and MEO satellites each have their uses, they both have issues with latency and data rates.
| parameter | LEO: 500-1200KM | MEO: 5000-20000KM | GEO: 36000KM |
| Height | Very low | low | high |
| Earth coverage | small | large | Very large |
| Satellite qty | Hundreds | 6 | 3 |
| Data Gateway | Local large quantities | Flexible region | A few fixed |
| Antenna rate | 10mins fast tracking | 1 hour slow tracking | fixed |
Figure 1 LEO/GEO/MEO satellite coverage area
LEO satellites offer significant advantages over their geostationary and medium Earth orbit counterparts; they are able to provide low-latency (30 times faster than GEO) and high-speed internet connections to remote and underdeveloped areas of the Earth. LEO satellites require hundreds to thousands of satellites to cover the Earth’s surface, forming a cross-linked mesh network. This mesh network not only expands global coverage, but also improves the reliability of connections – for example, if one satellite goes offline, another can immediately fill in in case the signal is lost. Currently, most LEO satellite deployments are driven by private companies and government agencies; companies such as SpaceX, OneWeb, Amazon’s Kuiper Project, and Telesat have invested heavily in the deployment of LEO satellites, ushering in a new era of global network interconnection and easy access to data.
Satellites play an important role in promoting global connectivity. As shown in Figure 3, they have two main tasks: one is to communicate directly with the earth to provide support for many end-user terminals in different industries; the other is to transmit data back to the earth directly or via inter-satellite links (ISLs). As more LEO satellites are launched, communication speeds are significantly improved and coverage is expanding; the transmission of information from space to the earth becomes more convenient and has less latency.
| Satellite | Orbit height | Application |
| GEO | 36000KM | Telecommunications, broadcasting, weather forecasting, remote sensing, navigation |
| MEO | 5000-20000KM | Telecommunications, GPS and other navigation |
| LEO | 500-1200KM | Delay-critical applications, financial transactions, autonomous vehicles, remote video surgery |
Figure 2 Non-terrestrial networks, including terrestrial inter-satellite links (ISLs) and application connectivity
2. Satellite basic components
Satellites are complex systems that contain multiple functions depending on the mission; this article will focus on the transponder component inside the communications payload module. A transponder is a subsystem in the payload module that is responsible for sending and receiving signals; it usually contains amplifiers, receivers, and transmitters for communication purposes.
Figure 3. Example of basic satellite components
3. Frequency spectrum used for satellite communications
Most satellite deployments use the L to Ka bands. However, more satellites are currently moving towards higher frequency bands such as the Q/V and E spectrum; as shown in Table 1 below.
| Frequency
band |
Downlink frequency
GHz |
Downlink bandwidth
GHz |
Uplink frequency
GHz |
Uplink bandwidth
GHz |
Note |
| L-BAND | 1.535-1.56 | 0.025 | 1.635-1.66 | 0.025 | Real-time monitoring of equipment status at remote locations and enabling machine-to-machine communication |
| S-BAND | 2.5-2.54 | 0.04 | 2.65-2.69 | 0.04 | For weather radar, surface ship radar and NASA communications, satellite television, mobile broadband services, radio broadcasting and airborne Internet |
| C-BAND | 3.4-4.2 | 0.8 | 5.8-6.725 | 0.925 | Provide voice and data transmission services from ship to land |
| X-BAND | 7.25-7.75 | 0.5 | 7.9-8.4 | 0.5 | Used for SATCOM, military SATCOM and radar applications |
| Ku-BAND | 10.0-13.0 | 3 | 14.0-18.0 | 4 | Used for SATCOM, fixed satellite services and broadcast satellite services |
| Ka-BAND | 17.7-21.2 | 3.5 | 27.5-31.0 | 3.5 | Used for SATCOM, military SATCOM and 5G telecommunications |
| Q/V-BAND | 37.5-42.5 | 5 | 42.5-51.4 | 8.9 | Used for voice, data and video communications |
| E-BAND | 71.0-76.0 | 6 | 81.0-86.0 | 5 | Provides extremely high throughput satellite communication services |
Table 1 Satellite Communications (SATCOM) Spectrum Allocation
To serve 5G non-terrestrial network applications, 3GPP has also allocated NTN bands. Table 2 shows the existing NTN bands in the L&S bands, and the newly proposed bands in the K and Ka bands.
4. Integration of satellite and 5G networks
Broadband services provided by large LEO satellite constellations are becoming increasingly popular around the world. This trend, coupled with the integration of satellite networks into the 5G ecosystem, is further driving the growth of the satellite communications market.
In addition, cellular communications are becoming part of the satellite ecosystem. The introduction of 5G wireless technology in 3GPP Release 17 enables 5G systems to serve non-terrestrial networks (NTNs). NTNs are designed to expand global network coverage, especially in rural and remote areas, and facilitate direct connections between mobile devices, the Internet of Things (IoT), and commercial autonomous vehicles and satellites. This integration enables the satellite industry to fully leverage the scale of the 5G ecosystem.
3GPP Release 17 defines 5G New Radio (NR) NTN and 5G IoT NTN, as shown in Figure 4. It focuses on leveraging satellite transparent payload architecture and UEs with GNSS capabilities; Figure 4 shows the expected use cases for 5G NTN.
Figure 4. Complementary NTN 5G NR and IoT use cases
Other application scenarios include…
- Areas with insufficient coverage such as agriculture, mining and forestry
- Disaster area communications when terrestrial communication networks are damaged
- Broadcasting information over a very wide area
This article explores the impact of LEO satellites on global communications, focusing on their key role in areas such as telecommunications and Earth observation. The number of LEO satellites in commercial constellations is expected to double by 2029; providing low-latency, high-speed Internet access to remote areas through mesh networks. Investments by large companies such as SpaceX, OneWeb, and Amazon’s Kuiper Project mark a major shift in improving global connectivity. In addition, we also examine the integration of satellite networks with the 5G ecosystem through NTN, thereby expanding frequency spectrum to improve coverage, especially in underserved areas. This integration not only drives market growth, but also highlights the important role of the satellite industry in advancing 5G infrastructure and global communication capabilities.
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