Just shortly before Christmas and seemingly pretty much unnoticed by the rest of the world, RCR Wireless reports that mobile network operator One NZ in New Zealand has launched Starlink Direct-to-Device SMS text messaging with four unmodified smartphones! To date I can only find the ‘official’ description of how the service works and only the promotional video on Youtube. Too bad, I’d really be interested in some more technical details and field reports by independent people. I’m sure these will come in due time, but for now, there are at least a few interesting details in the material provided.
Like in previous announcements, it is stressed that this service launch is the first of its kind which uses unmodified smartphones. While there are other satellite texting capable smartphones such as a Bullitt / Motorola smartphone model released about a year ago, these device devices contained a separate chip and also required a separate app for satellite texting. This service, however, seems to use the built-in SMS messenger for communication and no extra hardware in the device.
In the official launch video there’s a 4G logo above the uplink/downlink arrows and there is one dark signal bar and three white ones, i.e. the signal level is very low. That would make sense. And perhaps even more interesting: A VoLTE logo is shown next to the 4G logo. If taken at face value, and I would like to remind you that this is all unverified at this point, and I don’t have any internal insight into what exactly has been launched whatsoever, this seems to indicate that the phone is fully LTE IP and IMS attached.
In One NZ’s How-To it is mentioned that the network name shown in the status bar is ‘One NZ Starlink’. This could be an indication that the satellite connection uses its own 3GPP Mobile Network (MNC) code. Hence, in automatic network selection mode, the device will only go there if the home network becomes unavailable. Also interesting: There is no ‘R’ roaming indicator over the signal bars, which could mean that One NZ uses the ‘Equivalent PLMN’ function. And this in turn might make it a bit difficult to just use manual network selection and lock the phone to the satellite network as the device would jump back to a better ground based cell if available. And once again: All of this is just ranges between educated guessing and speculation.
Further, the press announcement mentions that service is not continuous, as there are not enough ‘Direct to Device’ capable Starlink satellites in orbit yet. The announcement further says that sometimes, one has to wait for a few minutes until SMS messages are sent or received. Fair enough, its early days.
Having an LTE and VoLTE logo on the display has another interesting implication: LTE requires a ‘default bearer’ to be established, which means that IP connectivity is there in principle. So far, the service is limited to SMS text messaging only, but the groundwork for IMS based telephony and some sort of Internet access is there. This would imply that voice calls and IP connectivity must be blocked on the network side for now.
One thing that has me puzzled a bit is why only four smartphones are working with the service so far, with more ‘being tested’ at the moment. ‘Unmodified devices’ does not necessarily mean that no additional software in the modem is required to talk to the satellite LTE system. Or perhaps not, and One NZ does some kind of IMEI whitelisting to only allow devices it knows really work. If that is the case, then I guess there will be many LTE attach rejects, perhaps eloquently answered with reject cause #11 (PLMN not allowed) to stop devices from further requests. Not nice to speculate so much, I’d really like to beam me to New Zealand and try it out my self.
And as we are wildly speculating today: This source says that Starlink uses a 5 MHz chunk of LTE band 3 spectrum (1800 MHz) it has received from One NZ over New Zealand. Sounds reasonable, but again, not verified.
So much for today, let’s see when more tech details are revealed.