The switchover for cellular was 3G (HSPA) > 4G (LTE).
Data transmission over 3G is encapsulated over the audio channels, and pure LTE is VoIP over data channels. Most networks relied on both during the transition, and it’s the reason many ‘4G’ capable handsets were deprecated when 3G networks were shut down, as they never fully implemented VoIP for audio calls.
Incidentally, DOCSIS (v1.0 - 3.0) downstream channels are encapsulated within MPEG2 frames.
The switchover for cellular was 3G (HSPA) > 4G (LTE).
Data transmission over 3G is encapsulated over the audio channels, and pure LTE is VoIP over data channels. Most networks relied on both during the transition, and it’s the reason many ‘4G’ capable handsets were deprecated when 3G networks were shut down, as they never fully implemented VoIP for audio calls.
Incidentally, DOCSIS (v1.0 - 3.0) downstream channels are encapsulated within MPEG2 frames.