YouTube: https://www.youtube.com/watch?v=DnuafW55nJM&list=PLnKL6-WWWE_VNp6tUznu7Ca8hBF8yjKj2&index=38

1. VoLTE
Closer to VoIP than LTE
Piotr Gruszczyński
next Generation Technologies
pg@nextgt.com

2. next Generation Technologies – consultancy

3. LTE Network
Evolved RAN (eNodeB)
Evolved Packet Core (Mobility Management Entity, Serving
Gateway, Packet Gateway)
Provides IP communication – encapsulation (bearer), address,
routing

4. VoLTE
Voice over LTE
Voice over IP …
… over LTE
ViLTE
Video over LTE
Components
Communication protocol – SIP
Media description – SDP
• Codec negotiations
• RTP/IP parameters (addresses, QoS requirements)
IMS, IP Multimedia System

5. IP Multimedia System
Call Switching Control Function
Proxy – interworks with serving IP network (LTE)
Servicing – controls access, QoS, flow etc
Home Subscriber Server

6. VoLTE on the market
Why not?
Most of LTE operators are 2G/3G operators
For voice CS Fallback is used
If yes, then when?
LTE operator that has no legacy network
Spectrum re-farming
Better QoS

7. How VoLTE is better than VoIP?
With LTE
Any VoIP-like solutions shall work good
As well as Skype,Viber,Hangout etc
Advantage of VoLTE
VoLTE will be treated better by LTE, with proper QoS delivered
Interworking with other telephony networks is provided, including
VoLTE support in roaming
Handover between LTE, 2G/3G or WiFi networks can be provided
without service interruption

8. VoLTE - QoS
IMS link to LTE
via Policy and Charging
Control (PCC)
DIAMETER based
Policy Control Rules Function
(PCRF) as mediator

9. VoLTE to legacy telephony
With Telephony Application Server (TAS)
Dispatch via Border Gateway,Media Gateway

10. VoLTE to (own) 2G/3G
Single Radio Voice Call Continuity
IMS to Mobile Soft Switch

11. VoLTE to VoWiFi
EPC session maintained
Terminal awareness
PCRF authorisations

12. VoLTE roaming
P-CSCF and V-PCRF - in visited network
S-CSCF and H-PCRF - in home network

13. VoLTE and IPX
SIP/SDP signalling – Media Gateway Controller
DIAMETER signalling – DIAMETER Routing Agent
Traffic – Media Gateway
DNS, IPSec, QoS

14. Questions?
Piotr Gruszczyński
pg@nextgt.com