IMS and 5G

It has been 3 years since I started this blog. It was around that time back in 2014 when I heard about 5G for the first time. It was funny, we were just doing the first 4G/VoLTE deployments, everything was new to operators and someone was already dreaming about the next version ūüôā In 2017 the 5G is still not finalized but we have done quite a few steps forward and 3GPP has created a lot of specifications (Rel-15) which uncover the concept (actually we have 5GPP too!).

5G trial deployments Рmap, © GSMA Intelligence 2017

Maybe you have already heard about some features as Dynamical Network Slicing, CloudRAN, Network-as-a-Services, …¬† Some basic 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 to stay in the operators’ networks?

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.


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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.

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