Google is Bringing Satellite Messaging To Android 15

Google's second developer preview for Android 15 has arrived, bringing long-awaited support for satellite connectivity alongside several improvements to contactless payments, multi-language recognition, volume consistency, and interaction with PDFs via apps. From a report: These developer-focused betas are a proving ground for features that will likely make it into the final public release scheduled for later this year. According to Google, public beta releases should be available to test between April and July. The latest developer preview addresses some nuisances and security concerns experienced by Android users, such as making apps more aware of why some services might be unavailable when devices are using a satellite connection. This is also the first official confirmation that Android 15 will come with satellite messaging, with Google's press release saying that the new preview includes support for "preloaded RCS applications to use satellite connectivity for sending and receiving messages."

How powerful does the transmitter need to be?

[ardmhacha]

How powerful does the transmitter in a cell phone need to be to reach a satellite in orbit?
Will current phones be able to send a detectable signal that far?

Re: How powerful does the transmitter need to be?

[wbcr]

The satellite network Starlink is building is on LEO, that is around 300km above us. So I presume the signal must be clear enough at least at distance of 400-500 km. Not sure about the power transmission requirements but it certainly will be very low data rate. I don't think it will work in the presence of obstacles or indoor though.

Re:

[test321]

As a comparison point, the Iridium communicators (low earth orbit 666 km) use an extra 10 W for the communication (15 W transmission vs 5 W standby; according to a comment on this page https://www.morganscloud.com/j... [morganscloud.com] )

Re:

[CEC-P]

I 1000% also need to know this. I'm not networking guy but 200mW with no dish is absolutely not making it into space (low Earth orbit, whatever).

Link Budget proves you wrong.

[stooo]

you are very wrong.
with 200mW and no dish you can make it to LEO. An example of linkbudget:

Tx power = 23dBm
Tx antenna gain : +2 dBi
misc losses (misalignement, clouds, etc...) : -10dB
Free space loss 300km @1GHz : -142 dB
RX antenna gain : +3dBi
Power at RX : -124dBm

Now for sure you have to go to a very low low bitrate to have such a -124dBm sensitivity, think in 100bps-10kbps, that is crystal clear.
Does someone have typical bitrate/sensitivity figures numbers for the modern LTE/direct sat to cell modulation sc

Re:

[evil_aaronm]

You're not thinking broadly enough. See, they're going to put AI, from Huang's Nvidia, on the satellites, and then they'll start a subscription service so you can chat with the satellites.

Did I hit all of the current buzzwords?

Re:

[ElimGarak000]

Stop. You'll make Wintermute cry.

This is a good and useful improvement

[Striek]

I'm a pretty regular user of Garmin's satellite devices during the summer months, I frequently travel well beyond the reach of cellular reception for days or weeks at a time. Having one of these devices is great. What we usually do is contract with a local outfitter nearby and ask them to start looking for us if we stop giving daily location updates. The problem is that such devices regularly cost between $500 and $1000, and it's another monthly plan. Signal strength also noticeably and problematically degrades with thick cloud cover or even a dense tree canopy.

With this upgrade, this would now be possible with a Pixel. The issue though is battery life. Compared to a dedicated satellite communicator, a cellphone is an absolute HOG on battery. There's no way they'd work for me for weeks at a time. Who it will work for, though, is people who drive outside of cell reception on a long drive and break down, or day hikers traveling beyond reception. Maybe people on cruise ships would find it useful. Personally, I think it's a great addition.

To answer another poster's question, the best source I can find theorizes that an InReach transmits at 1.6W. Given a clear sky, that will reach satellites at least in LEO. A personal locator beacon (PLB) transmits at 5W, and will not only reach satellites in geosynchronous orbit, but also light up every air traffic controller's screen for a hundred miles. Transmit power is not an issue.

Re:

[timeOday]

I am also excited to stop having to carry a PLB. This is about the only thing I can think of that would motivate me to buy a new cell phone, although would be even better if I don't have to.

Ask for power, it hardly matters. What matters is energy. A few watts for a tiny fraction of a second is a very small amount of energy.

5G Non-terrestrial Frequency Range

[jonfr]

The 5G technical specs now have three Non-terrestrial Frequency Range added. So I would guess this needs to be a phone that supports those bands. Those bands are n254 (2400Mhz, 1610 – 1626.5 Uplink, 2483.5 – 2500, Downlink), n255 (1600Mhz, Uplink, 1626.5 – 1660.5, 1525 – 1559, Downlink, US Only), n256 (2100Mhz, 1980 – 2010, Uplink, 2170 – 2200 Downlink, IMT). This are FDD setting. This is not supported by 4G, since that has been out of development for a while now (just security updates currently).

Normal mobile phone transmits at power of 1W at maximum on this higher frequencies.

https://en.wikipedia.org/wiki/... [wikipedia.org]

God created the heavens and the earth

[jfdavis668]

and now you can text him/her.