SpaceX, operator of the Starlink satellite service, is fighting for special permission from the US regulator Federal Communications Commission (FCC) to provide cellular services to smartphones from space via Starlink satellites. Company representatives are also using tough tactics when attempting to negotiate better radio conditions for themselves so they can offer gigabit Internet. The controversy begins in the United States and at first glance only affects SpaceX, the FCC, and network operators there. But many of the FCC’s decisions in the past have been unprecedented for other regulators. It is therefore likely to have consequences for all terrestrial mobile phone operators on the planet and therefore also for all mobile phone users.
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Technically, it has long been possible to supply mobile phones via satellite; Depending on design and approval by the FCC, low-flying satellites (Low-Earth Orbit, LEO) use radio bands typically used on Earth to connect commercially available LTE and 5G smartphones. Satellites mediate between smartphones and ground stations of mobile network operators.
Although SpaceX has been offering global Internet via its Starlink satellites for several years, it previously required stationary terminals ranging from tablets to towel-sized antennas. Now SpaceX wants to supply ordinary cell phones with the new generation of satellites as soon as possible. To achieve this, the company is collaborating with T-Mobile, the American subsidiary of Deutsche Telekom. SpaceX currently has more than 200 satellites in orbit specifically designed for mobile communications. According to Starlink employee Michael Nichols, more than 320 such satellites will be needed for public operation in the final phase.
But while SpaceX’s Falcon rockets have been bringing 13 new Starlink V2 Minis into orbit with each flight for several months, the evolution of radio coverage is clearly not going according to plan. SpaceX still has September 2016 a document to the fcc The final expansion promises “gigabit speeds for every user.” But current Starlink technology clearly does not do this. It comes from an application From SpaceX to FCC Outside. In this, SpaceX is demanding significantly better infrastructure conditions for itself than those provided by the FCC specifically for such services.
Invoice without payee
In retrospect, SpaceX’s 2016 announcement seems premature, as the FCC had already outlined the framework for space delivery in April this year (pdf, 160 pagesIt also involves significant limitations for coexistence with terrestrial mobile networks. Accordingly, spurious emissions from satellites in the mobile phone bands at 600, 700, 800 and 1990 MHz are permitted to exceed a limit of −120 dBW/m.2/MHz (out-of-band emissions, OOBE). Mobile network operators call this globally accepted limit the “-120 limit”.
Depending on the Earth orbit altitude (GEO, MEO, LEO), satellites cover different areas. However, the services are intended to be largely global. On the other hand, High Altitude Platform System (HAPS) only serves cities or small areas and flies at twice the altitude of commercial aircraft.
Only this limitation enables limited occupancy and thus efficient use of the radio spectrum. Although regulatory authorities assign each service a frequency band of a certain width, it is technically impossible to completely disappear a signal at a channel or band boundary. Depending on the quality of the transmitter and filters, it flattens more or less sharply at the edges, causing annoying spurious emissions to always leak into neighboring areas. In order for services there to still function, regulatory authorities set maximum levels of spurious emissions and transmission system operators must comply with the limits.
SpaceX now claims that the limit is too strict and results in reduced data rates, rendering the satellite technology unusable for voice and video communications. To meet the FCC’s outline requirements, SpaceX would have to halve Starlink transmission power, significantly reducing data rates. That’s why experts currently expect Starlink mobile communications satellites to provide 100 Mbit/s at best.
SpaceX further states that “a blanket limit for all bands from 600 to approximately 2000 MHz is inappropriate.” The two 5 MHz narrow bands from 1910 to 1915 MHz and 1990 to 1995 MHz are reserved for Starlink and are why “frequency-specific limits make sense”. According to our own calculations -110.6 dBW/m2/MHz is enough, that is, about nine times the FCC limit. This means Starlink can deliver gigabit speeds and still avoid interference with neighboring bands. As examples, the company cites the 1895 to 1910 MHz and 1975 to 1990 MHz ranges, which are used by its affiliate partner T-Mobile; These will not be affected by Starlink.
salt on the wound
US network operators AT&T and Verizon strongly deny this information. According to SpaceX’s own calculations, the limit required by SpaceX would reduce throughput on its network by 18 percent. There can be no question of increasing the -120 limit in the 1900 MHz band. Furthermore, they rubbed salt into SpaceX’s wound: The company did not clearly explain why Starlink satellites could not comply with the FCC’s limits without halving transmission levels.
The idea of ​​SpaceX has also been scaring European network operators for a long time. A group that also includes Telefónica and Vodafone is now threatening the FCC with straight suitIt owes SpaceX: “Any relaxation of the limitations affecting the management of allocated frequencies will give rise to claims for damages.” The current -120 limit is “the minimum level of security that is required for mobile network operators to continue to provide the promised quality of terrestrial services.” Furthermore, if more satellite systems of this type are expected to go into operation or if an operator launches additional satellites into orbit, higher levels of interference will also be at risk of affecting terrestrial mobile phone operators and their customers. .
What seems noteworthy is that some of these network operators themselves cooperate with SpaceX’s competitor AST Spacemobile. AST itself is working on a service for mobile phones and has so far launched five satellites and won many mobile network operators around the world as customers.
Exchange of blows about gangs
In early October, SpaceX joined An updated notification to the FCC Continued: “Foreign investors and AST’s partners will do nothing to slow progress. AST and its investors continue their scorched earth campaign to disrupt competitive direct routes, no matter what their efforts mean. “That Americans are left without emergency connections and reliable service in U.S. satellite systems are at a competitive disadvantage in international markets.”
This reaction is partly related to the damage caused by recent hurricanes in the United States. SpaceX wanted to offer Starlink-mediated voice services as a replacement for smartphones if range was extended until the destroyed cellular infrastructure could be repaired. However, the FCC stuck to the -120 limit. Starlink then offered only a messaging service.
The further tone of SpaceX’s filing to the FCC suggests an irritable mood. Among other things, SpaceX vice president David Goldman writes: “Apparently not content with harming competition in the US, AST is taking its disinformation campaign overseas, targeting European investors and partners to reiterate its arguments. Is recruiting and competing to cause harm there too.”
it depends on the size
Such statements divert attention from the technical problems Starlink faces in complying. You can get a rough idea indirectly: When it comes to antennas, the area that matters is as large as the gain of the antenna. This means the receiver gets a better signal, which means higher data rates. When sending, you can reduce the output power and thus also reduce spurious emissions for the same speed.
SpaceX has provided Starlink satellites with approximately 25 square meters of mobile communications antenna. The first generation AST satellites already exceed this: their first test satellite, Bluewalker 3, communicates via a 64 square meter antenna array. This makes it the largest LEO satellite. The housing behind the group antenna is a modified mobile phone base. It covers an area of ​​about 777,000 square kilometers using huge antennae.
With Bluewalker 3, AST Spacemobile demonstrated the first mobile phone call in internal testing in early 2023. AST recently launched BlueWalker 3 with five new Bluebirds with improved technology and reportedly three times the antenna size. The entire constellation is expected to consist of 243 satellites at an altitude of 725 to 740 km. AST submitted an application to operate to the FCC in April 2020. The FCC has not yet made a decision on this, but has approved all previous steps in this direction. It is still unclear whether the FCC will grant SpaceX’s demand. This process has been going on for several months and SpaceX has received several objections from mobile network operators.
Other companies around the world are working on satellite systems that will cover the planet with mobile Internet from orbit. These include Globalsat and Globalstar, as well as Iridium with Apple as Flywheel. Not all of them are designed for voice and data services. Apple and Globalstar have so far only planned text messaging for scenarios where terrestrial cellular is not available. Of course, they require a modern iPhone that has special technology for this operating mode.
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