VoIMS – IMS and 5G

Update:

This post is getting a bit rusty over the time. I plan to create some new stuff. Meanwhile I’d recommend to check GSMA IMS Profile for Voice, Video and Messaging over 5GS. And for those who want to know more 3GPP TR 23.700-10 Study on enhanced IMS to 5GC integration.

Maybe you have already heard about some features as Dynamical Network Slicing, CloudRAN, Network-as-a-Services, …  Some basic 5G principals we’ll briefly discussed also in this post. However my question is: What will be the change from the real-time communication point of view? What will be the 5G calling look like? Is the IMS (IP Multimedia Services, don’t confuse with International Microwave Symposium) to stay in the operators’ networks?

5G Deployments Sep, 2019 by 5G Americas

Seems that at the first stage the change will be less dramatic than when we introduced 4G. 4G was in many ways a revolution, whereas 5G is “only” an evolution. In fact 4G and 5G, at least in the beginning, will coexist and complement one each other. Still 5G will have a big impact on our existing technologies and the way we work with telecommunication networks.

5GS + EPC + IMS

VoLTE or RCS Voice Call?

Update: The information in this post became obsolete over the time. Recently we’ve got RCS Universal Profile standard, which defines Green Button Promise for Voice and Green Button Promise for IP Video Call Services and Enriched Voice Calling. I’m working on an updated material, which will compare RCS IP Calls and VoLTE/VoWifi calling and describe RCS Network Architecture.

 

It is similar with many OTT applications for calls and massaging. Which one is the right or at least decent one? The big advantage is that usually we can try it for free.  Anyway what is the difference between a voice call performed as VoLTE (or VoWiFi) and voice call which is transmitted via RCS?

The 4G networks were originally designed for pure data traffic. But the voice service is a must have feature and right now it can’t be fully replaced by VoIP. The voice service has to be reliable and fully compatible with the service from 3G (Blacklisting, Call diverting, Lawful intercept, Emergency calls, DTFM, etc.) and has to allow seamless fallback in case the 4G coverage is lost (eSRVCC). This new service is called VoLTE.