Satellite "Direct-to-Cell" launched by Starlink

babelfish1990

Starlink has launched the first batch of satellites to offer mobile connectivity to standard 4G/5G terrestrial mobile phones. While this technology is not likely to be an economic alternative to terrestrial mobile networks, it should be useful for plugging black-spots in mobile coverage, use at sea etc.

They don't yet appear to have any mobile network partners within the EU (maybe licencing difficulties?). Interestingly, the only European partner in the trial is eir's sister company - Salt in Switzerland. Eir & Salt appear to follow very similar strategies, so perhaps eir will be an early adopter of Starlink Direct-to-cell?

https://arstechnica.com/tech-policy/2024/01/spacex-launches-first-starlink-satellites-that-will-work-with-t-mobile-phones/

GIMP

Interesting times ahead, I wonder will this coverage work indoors too or is it external only?

babelfish1990

https://www.boards.ie/discussion/comment/121573008#Comment_121573008

They seem to be using a band in the 1900MHz region, so indoor penetration of roofs/walls should be similar to existing terrestrial 2G/3G/4G mobiles. The distance to the "base-station" in low-earth orbit will be much further than to a typical terrestrial base-station, but there won't be any obstacles if you have a clear view of the sky. Of course, A-Rated houses with lots of insulation, or houses with metal roofs will struggle to receive any signal from the satellites, just as the struggle to receive mobile signals currently. However, within a building users should fall back to WiFi calling. Satellite should be reserved for the really difficult scenarios where there is no coverage of broadband, and at sea etc.

The Cush

The FCC has approved 1990-1995 MHz (space-to-Earth) and 1910-1915 MHz (Earth-to-space) bands. In the US it's part of LTE Band 25 (FDD 1900MHz Extended PCS 1850–1915 / 1930–1995

https://www.scribd.com/document/612879369/Technical-Narrative-1

This 5 Mhz TDD block was previously licensed to O2 in Ireland as part of their 3g 2100 MHz mobile licence but I believe it was never used

babelfish1990

https://www.boards.ie/discussion/comment/121577655#Comment_121577655

I suppose a lot of the original 3G mobile licences have now expired in many countries, and this conveniently gives an opportunity for reallocating a small chunk of mobile spectrum for Space<>Earth communications. They probably don't need to use much spectrum, as this will only be used by a small number of devices that are outside of normal terrestrial coverage. The pricing is likely to discourage more widespread use.

The Cush

This block of spectrum, 1900-1920 MHz, was different to the main block of 3g FDD spectrum. Each MNO was allocated a 5 MHz TDD block if they wished to take it up as part of the licence.

Eir, Vodafone and O2 took the offer but two of them returned it a decade or more ago with the O2 block returned back in 2021. None ever used the spectrum to the best of my knowledge. Lack of compatible equipment may have been the issue at the time.

Iirc Three Ireland didn't take up the offer the block of spectrum.

Now the 1900-1910 block is allocated to Railway mobile services on a pan-European basis with 1910-1920 vacant