Nothing to do with premium connectivity.
The problem is with EE mast connectivity when moving to another mast band 20 which Tesla uses does not reconnect with the new mast.
Tesla and EE are trying to sort this, but band 20 is by far the best band for distance and penetration of structures.
I wonder if this is related to the way that EE (and Three) have to block access to band 20 from phones that don't support (or aren't provisioned for) VoLTE? Just speculating, but if Teslas don't (consistently) have access to band 20 on EE, then the degradation of service could be related to the way that EE are rearranging their network as part of their ongoing 3G shutdown.
The big problem that EE and Three have is that they don't have any 900MHz spectrum, so their 2G and 3G networks have significantly reduced coverage compared to their 4G network (and in future 5G - although obviously 5G coverage is currently more limited). There was a concern, therefore, that there are significant areas of the county where phones will show that they are in coverage, but without a VoLTE-provisioned handset will not be able to make voice calls - and in particular 999 calls. I don't know if it's still the case, but historically the solution was for EE and Three to block access to band 20 from non-VoLTE-provisioned handsets, to avoid the heightened risk of people believing they have the ability to make 999 calls when they don't.
This all happens because you need VoLTE (also known as 4G Calling) in order to make voice calls over 4G and 5G networks. Older handsets have to switch back to 2G or 3G to make voice calls - and in the case of EE or Three there's a heightened risk that there may be be no 2G/3G available to switch back to, despite your phone showing a good 4G signal. This risk can never be completely avoided with circuit-switched fallback, but O2 and Vodafone have the huge benefit of 900Mhz spectrum, which has similar range to band 20, so they aren't required to play these games as it's highly likely that if you have 4G coverage you'll also be within their 2G or 3G coverage and hence be able to make voice calls, even with an old handset.
4G, 5G and VoLTE are the future - 2G and 3G will be shut down in the coming years - but the transition is not without issue. Increasingly non-VoLTE handsets - or early VoLTE handsets which suffer from interoperabiliy issues - are unable to make voice calls when roaming to networks in countries such as the USA where networks are well ahead of us in shutting down 2G and 3G. And even if you had a modern, interoperable VoLTE handset, there were early problems with VoLTE roaming. Things will get better eventually - they are getting better, in fact - as all networks now have a huge incentive to make the new technology work properly, as they want to switch off the old. But it will take time to iron out all the issues.
roy
teslamotorsclub.com
