SpaceX sends first direct-to-cell Starlinks to orbit

SpaceX has put the first six Direct to Cell-capable Starlink satellites into orbit following a successful Jan 3, 2023 launch. Liftoff, which took place at 0344 UTC today, launched a batch of 21 Starlink satellites to Low Earth Orbit from Space Launch Complex 4 East (SLS-4E) at California's Vandenberg Space Force Base. SpaceX …

[Rahbut]

Genuine (Dopey) question... how do they use T-Mobiles North American spectrum? Presumably that same spectrum is used by other providers in other places? I can get that they might just "turn off the satellite" when it flies over somewhere other than America, but presumably the satellite can see a number of different countries from that far up... So, could it work in Europe, or would there have to be some kind of spectrum harmonisation?

[Anonymous Coward]

Pretty sure they'll stop transmitting the cell signal when they're not over the US. Also, Starlink is noted for beam steering (at least for the terrestrial dishes), so they should be able to only send the signal to where they want.

Just like how they work with getting licensing to provide Internet service in different countries, they should be able to selectively "turn on" cell service in other countries if/as they get licensed.

[Knoydart]

Likely spectrum will be “shared” by the local mobile operator- for the US it be T mobile, who will carve out a block of their spectrum holdings and switch off the range of frequencies from their terrestrial network. Then SpaceX switch on the matching frequencies on their spaces based transmitters.

SpaceX (along with Lynk and AST) will likely be using software defined radios so they can reconfigure their satellites to match the spectrum bands of countries they are passing over at the time. This will be tricky in places like Switzerland, as cross border issues will arise as the beams from space are very wide and hard to control. Australia and NZ will likely be fine, the secret sauce will have to be added for places like Switzerland to minimise these issues and interfering with neighbouring countries terrestrial cellular networks.

[MachDiamond]

"but presumably the satellite can see a number of different countries from that far up"

The satellites are very low (for a satellite) and are looking down with a restricted cone as well. Over Europe, they'll be able to see several countries, but over the US, China, Russia, etc, they won't. The sats are just a router in space, they must have a ground station to tie into the internet/phone network. Starlink isn't a backbone provider.

[Anonymous Coward]

Beam forming technology

Even more than traditional geostationary TV/Telecom satellite transponders, LEO satellites antennas like starlink rely heavily on so-called beamforming technologies (increasing and steering gain using massive MIMO antennas, phases, delays and interference) to focus their signal to specific geographical areas. These areas are still too large to be useful in dense, well served, urban settings, but this is not where non terrestrial networks (satellite networks) can claim their best business case.

Beamforming technologies are not only leveraged on satellite side (emission and reception beamforming), but also, in the case of classic rooftop Starlink antennas on the ground to track and to aim at the fast moving LEO satellite, with maximum efficiency. This is possible because rooftop antennas are fixed and can emit much more power than your average 2W smartphone.

In the case of smartphones, uplink beamforming is, best of my knowledge, not an option, simply because smartphones are not fixed (can't track or aim) and have only a few antennas. Therefore, in that case, all the heavy lifting is performed on the satellite side through higher sensitivity and robust protocol (e.g. harq: hybrid automatic repeat request). This is why only SMS is supported for now. Supporting voice will be a remarkable feat of engineering (if it really works).

[David Pearce]

Re: Beam forming technology

3G and LTE smartphone uplink is usually just 200 mW, GSM was 2W

[DS999]

Re: Beam forming technology

Supporting voice will be a remarkable feat of engineering

Not really. At least not bandwidth wise. With modern codecs you can get by with a little as 4 Kbps. No one talking about doing voice via satellite cares about stuff like "HD Voice", they'd give it the minimum bandwidth necessary for it to sound "OK".

The difficultly is likely to be maintaining a connection for very long - LEO satellites are moving across the sky quickly and if your head, a tree or a building gets in the way because of that movement the call will drop. It will need to be able to hand off calls between satellites (which would be downlinking to different ground stations) seamlessly.

We all know that handing off calls from a moving phone between cell towers isn't a solved problem (though it is better than it used to be) so I imagine there will be a lot of dropped calls. Not sure how much moving calls to data (i.e. VoLTE) was responsible for the reduction in dropped calls while driving, but at least they won't have to deal with circuit switched calls as I'm sure it will require VoLTE if it supports LTE at all. Likely the per minute cost will be exorbitant, so most people will want to keep the calls short, having them drop every few minutes might be a good thing!

[xyz]

You may SHOUT at will

I'm getting fed up with this "scam".

I have Starlink and I have a 'phone and no mobile signal and I get on just fine using WhatsApp, Telegram, Signal, Teams or Skype for comms. Ok, no one can call or sms me old fashioned stylee, but as 99. 9% of those calls or messages are from "rival" mobile companies wanting me to switch provder, I feel grateful.

I can connect to the cell network when I go into town daily, but then get dumped on by Orange Mobile Connect which Orange seems to use for spam and which you can't shut down.

The only use case I can see for a cell tower in spaaace is if I'm stuck in the middle of nowhere and need rescued. Or LoRa, but as the cell mafia is building its own paywalled LoRa style thing, expect much marketing and monthly charges.

To me, this is just another facet of the wifi calling scam which, I had to explain to my c-suite missus the other day, is using the wifi you're hooked onto like a cell tower and that phoning your mum in another country will be charged at the mobile operator's international mobile call rate and therefore not free. She had no idea.

And this is the nub of my problem with the whole mobile phone total connectivity thing. The phone companies are trapped in an out of date business model and are looking for any way create income.

I wish someone would start selling "no phone" phones that have no cell connectivity but come bundled with WhatsApp et al, maybe using a Skype number as a unique ID, connect that to your wifi and reduce the cell bunch to e-plumbers.

As I said, you can all now shout.

[Ian Johnston]

Re: You may SHOUT at will

"To me, this is just another facet of the wifi calling scam which, I had to explain to my c-suite missus the other day, is using the wifi you're hooked onto like a cell tower and that phoning your mum in another country will be charged at the mobile operator's international mobile call rate and therefore not free."

That's why when travelling I use Linphone and my home VOIP number.

[Anonymous Coward]

Re: You may SHOUT at will

"I wish someone would start selling "no phone" phones that have no cell connectivity but come bundled with WhatsApp et al, maybe using a Skype number as a unique ID, connect that to your wifi and reduce the cell bunch to e-plumbers."

Don't get out much do you? It's called "any $100 Mini PC or Raspberry Pi".

https://www.amazon.com/N40-Fanless-Celeron-Computers-3xUSB3-0/dp/B07QY8LDGX/

[Anonymous Coward]

Re: You may SHOUT at will

A small Android tablet would seem to be more suitable for this application.

[Alan Brown]

Re: You may SHOUT at will

not only that but such phones have been around for a while (and in any case you can achieve the same thing by removing the sim from any existing phone)

[DS999]

Phones that aren't phones

Any phone can be a not phone, if you buy a plan that's data only. I don't think a data only plan can be purchased for a phone directly from the big players in the US, but MVNOs like US Mobile and Red Pocket don't care and will sell you a data only plan for a smartphone.

Not sure about getting one that roams around the world, but they're probably out there.

[tip pc]

Re: You may SHOUT at will

I wish someone would start selling "no phone" phones that have no cell connectivity but come bundled with WhatsApp et al, maybe using a Skype number as a unique ID, connect that to your wifi and reduce the cell bunch to e-plumbers.

just put your phone in airplane mode or take the sim out and use face time (can use an email address instead of a number) / whatsapp / google chat / zoom / likely telegram / likely signal.

they used to sell a wifi enabled skype phone and some dect phones had skype functionality too.

my daughter uses my old ipad to make audio & video calls with family just fine & that ipad has no sim.

living out of mobile / cell range does sound idyllic though.