I'm not a radio guy, but I've read that the in-phone modems and antennas for Globalstar were much closer to existing designs. The spectrum is apparently right next to WiFi and Bluetooth bands.

Globalstar's technology over everyone else. They've just been crude bent pipes up in the sky. They still are. C-3 is just a bunch of new radio repeaters.

Globalstar's original network was just CDMA over the bent pipe satellite link, their second-gen Duplex network (sold as Sat-Fi 2) was an attempt to go WCDMA, then Apple dangled a lot of cash at them to build out and drop the entire Sat-Fi 2 product, the entire WCDMA core, and go roll Apple's new toys out for them. I'm assuming C3 is going to be heavily LTE-based if it isn't already at this point.

(I had a Sat-Fi 2 device and it was an interesting and short-lived experience. I was also there for the weird interim 201x satellite failure era - I remember having to pull up the Optimal Satellite Availability Tool to go see exactly how many long ~2-10 minute windows I could make phone calls in with a GSP-1600.)

((Double-fun-fact: The GSP-1600 is still actively used on Globalstar today, and it's one of the only tri-mode phones that existed of the era. It was satellite via GSTAR, then had CDMA for local calling and AMPS for the sticks. I had my GSP-1600 activated on a Verizon MVNO for local calls, which was a blast to use.))