Since the inception of commercial satellite systems in the 1960s, satellites have expanded their capabilities to provide a diverse and far-reaching array of vital services all over the world.
Satellite communication is a pivotal technology that enables the transmission of information, data and signals between various points on Earth and space through the use of satellites. This revolutionary mode of communication has transformed how people, businesses, governments and even scientific endeavors connect and share data across vast distances.
By leveraging the principles of electromagnetic radiation and advanced engineering, satellite communication has overcome geographical barriers and provided crucial solutions for global connectivity, remote sensing, navigation, broadcasting and more. Satellites positioned in different orbits play key roles in establishing communication links that facilitate real-time and reliable interactions.
The complexity of satellite communication involves intricate systems onboard the satellites, including transponders, antennas and processors, as well as ground stations equipped with high-tech equipment for signal reception, processing and transmission. From enabling international phone calls to delivering weather forecasts, disaster management and scientific research, satellite communication has revolutionized the way we communicate, collaborate and gather information in the modern age.
Because terrestrial networks face limitations, non-terrestrial networks elevate the resilience, reliability and reach of communication, underscoring their indispensable importance in building a more connected and informed society.
With the growing demand leading to an increase in both the quantity and scale of satellite constellations, the effective management of this “space within space” becomes imperative to ensure long-term sustainability.
Global Progress
In the upcoming ITU World Radiocommunication Conference 2023 (WRC-23), such discussions will be crucial toward enhancing both radiocommunication services and the use of radio-frequency spectrum and satellite orbits.
The development and implementation of new technologies should be encouraged at the conference and beyond, particularly in the fixed-satellite service (FSS) for broadband applications, as these systems are capable of providing high-capacity and low-cost means of broadband communication even to the most isolated regions of the world.
Indeed, frequency bands such as 37.5-39.5 GHz (space-to-Earth), 39.5-42.5 GHz (space-to-Earth), 47.2-50.2 GHz (Earth-to-space) and 50.4-51.4 GHz (Earth-to-space) have been globally allocated on a primary basis to the FSS.
As a result, satellite systems are increasingly being used to deliver broadband services, which can help enable universal broadband access. In addition, the frequency range of 43.5-45.5 GHz is primarily designated for mobile, mobile-satellite, radio navigation and radio navigation-satellite services.
Moreover, to meet the evolving requirements of modern civil aviation, satellite systems can be used for the relay of VHF communications compliant with International Civil Aviation Organization (ICAO) standards. They do this while operating under the aeronautical mobile service in order to complement terrestrial communication infrastructures when aircraft are operating in oceanic and remote areas.
Satellite Deployments
Satellites are categorized into four general types based on their orbital attributes: Low Earth orbit (LEO), positioned between 200 and 2,000 kilometers above the Earth's surface; Medium Earth orbit (MEO), mainly located between 8,000 and 20,000 kilometers above the Earth's surface; geostationary Earth orbit (GEO), stationed at a fixed position 35,786 kilometers above the equator; and highly elliptical orbit (HEO), which may extend to 40,000 kilometers from Earth at its farthest point in the orbit.
To ensure operational integrity while averting disruptive interference, the ITU designates frequencies, positions (for GEO satellites) or orbital attributes (for non-geostationary satellites) for every transmitting and/or receiving satellite within each orbital category. These allocations are documented in the Master International Frequency Register (MIFR).
When necessary, coordination between satellite operators and centralized global registration fosters efficient spectrum and orbital resource utilization across nations and discourages the hoarding of frequencies that could be used for other purposes.
The process of introducing new satellite deployments involves intricate technical calculations and collaboration among established administrations and operators whose satellite systems and terrestrial stations might otherwise be affected by transmissions from a new satellite.
As an example, in a bid to enhance broadband and 5G coverage nationwide, the UK government is contemplating a potential £160 million satellite fund aimed at advancing the next generation of satellite communications development, predominantly represented by LEO satellites. These satellites will prove instrumental in delivering connectivity to remote and rural areas within the UK.
In line with this, Ookla asserts that the realization of universal Internet access can be comprehensively achieved through satellite constellations positioned in LEO, coupled with high data transmission rates (exceeding 200 Mbps) and low latency (below 100 ms). This compelling vision has attracted substantial investments from prominent global technology companies.
Additionally, LEO satellite systems are poised to play a crucial role in the era of the Internet of Things (IoT). As more devices become interconnected, the need for reliable and widespread connectivity becomes paramount. LEO satellites are equipped to meet this demand, providing the essential infrastructure for IoT applications spanning smart homes, cities, autonomous vehicles and industrial automation.
Nonetheless, the successful operation of LEO satellites hinges on their ability to withstand the challenging conditions of space. Components must surmount hurdles such as extreme temperature fluctuations and intense high-energy particle radiation. Moreover, these components must execute missions while contending with a limited power supply, an absence of repair options and a restricted operational lifespan.
Enhancing Spectrum Utilization
There are potential mitigations that might lead to more efficient use of the satellite-focused spectrum. This can help address current and future demand requirements.
One avenue involves advancements in satellite antenna beam-focusing technologies, which could enable satellites to employ smaller, more targeted beams. By implementing geographical discrimination, frequency bands can be repurposed, thereby amplifying satellite capacity.
Incorporating novel transmitter and receiver technologies, as well as adopting refined standards, could also optimize spectrum use. This encompasses innovative, spectrum-efficient waveforms, improved compression methods and filtering techniques to eliminate undesirable signals.
Furthermore, augmenting the efficiency with which satellite networks share spectrum resources with other users (such as terrestrial applications) assumes paramount importance. Simultaneously, alterations to satellite network parameters, such as stipulating a minimum diameter for transmitting earth stations or imposing constraints on the power flux density radiated towards other satellites, could potentially reduce the orbital separation between GSO satellites.
Conclusion
Satellite communication serves as a transformative tool for digital inclusion and telecommunications, enabling previously underserved or unreachable populations to benefit from the advantages of modern communication technologies. Its ability to transcend geographical barriers and offer reliable connectivity holds immense potential for improving the quality of life, fostering development and driving innovation in diverse communities around the world.
