I'm no LTE expert, but I'm pretty sure that it handles overlap: you can run LTE diagnostic apps on Android that will display all the visible base stations - often many are visible, sometimes 3 or more on the same band. Your phone looks at what's available and picks a combination with the best signal strength (sometimes it will connect on 2 or 3 different bands simultaneously with carrier aggregation).
But even then, most carriers have many bands/channels (EARFCNs) available - and presumably only a small slice of bandwidth is needed for this service considering it's (initially) only for text messages. Finding 5 Mhz on one of the higher LTE frequencies wouldn't be so hard for many carriers, even if it does need an exclusive channel.
Re:Starlink Direct to Cell
by TorKlingberg on Thursday October 12, 2023 @04:50PM
(#37863010)
TDM seems difficult with the long time delays to satellites, but maybe. LTE is pretty flexible and can use bands as small as 1.4 MHz.
It was only 1G and 2G (GSM) that needed to avoid overlap.
Afaik older cellular protocols were relying on zero overlap between base stations serving the same frequencies, leading to a nice coloring problem that would seriously suffer if someone tried to fit in LEO cells.