Warsaw University of Technology Karthik KrishneGowda
pg. 1
VoLTE
Voice Over LTE, IMS & the Future of Rich-
Media Services in the 4G Era
Warsaw University of Technology Karthik KrishneGowda
pg. 2
Introduction:
The GSMA VoLTE (Voice over LTE) initiative was formally
announced on 15th February 2010. In establishing the VoLTE
initiative, GSMA has adopted the work of the One Voice
Initiative as the basis of the work to lead the global mobile
industry towards a standard way of delivering voice and
messaging services for Long-Term Evolution (LTE). Using IP
Multimedia Subsystem specifications developed by 3GPP as its
basis, GSMA have expanded upon the original scope of One Voice
work to address the entire end-to-end voice and SMS ecosystem by
also focusing on Roaming and Interconnect interfaces, in
addition the interface between customer and network.
The One Voice Profile:
One Voice profile defines a minimum mandatory set of features a
wireless device (the UE) and network are required to implement
in order to guarantee an interoperable, high quality IMS-based
telephony service over LTE radio access. The scope includes the
following aspects
• IMS basic capabilities and supplementary services for
telephony
• Real-time media negotiation, transport, and codec’s.
• LTE radio and evolved packet core capabilities
• Functionality that is relevant across the protocol stack and
subsystems
Warsaw University of Technology Karthik KrishneGowda
pg. 3
The UE and network protocol stacks forming the scope of the One
Voice profile are depicted in the figure below:
Migration from 3G to LTE
Mobile service providers have not adopted much SIP or IMS today.
However, nothing precludes them from doing so, and initiatives
like Rich Communication Suite may incent adoption of SIP / IMS
ahead prior to LTE deployment. The area with the largest SIP
adoption is the core and IP interconnect borders, which does lay
nice groundwork for migration to the 3G and 4G access networks.
LTE is on the 5-year horizon for some 3G service providers, so
they have time to roll-out IMS ahead of their 4G deployment.
VoLGA and VoLTE both offer migration, but only VoLTE offers
services beyond voice and messaging of yesteryear. MSC VoIP is
an interim step as well, where some investment is preserved for
both voice-the MSCs at the outset-and the multimedia-SIP
infrastructure for the years ahead.
