VoLGA Forum is one such body proposing a solution and its backed by quite a few well known industry players.
In the LTE World Summit, Franz Seiser of T-Mobile Germany spoke about VoLGA. Here is a summary from his presentation:
In order to ensure LTE will be used as much as possible, voice-and messaging services need to be supported on LTE networks in high quality asearly as possible.
The main Drivers being:
- Ensure acceptance of LTE as an possible next generation PLMN
- Shift traffic to new network as fast as possible
- Avoid price competition with DSL
- delivering a seamless user experience (voice hand-over to existing 2G/3G networks)
- with proven, commercial quality
- availability in 2010 (SMS) /2011 (voice) latest
In a post earlier, I discussed about the possible voice options for LTE and that generated quite a discussion relating to GAN. Recently Dean Bubley and Martin Sauter have covered this VoLGA issue and in general Voice over LTE in far more detail than I have earlier or even in this post. Please see the links at the bottom to read their post details.
Specified 3GPP solutions for Voice/SMS in LTE do not meet all requirements because:
CS Fallback ruled out due to customer experience and non-LTE usage
- issues with customer experience (call set-up time increase >1.5sec., no parallel voice/data if legacy network is 2G w/o DTM)
- not using LTE radio for voice
- requires changes to Rel-4 architecture MSC-Servers
- has much more impacts than originally envisaged
IMS based solution has very high complexity; availability and stability notfeasible in time, roaming eco-system is not yet existent
- solution would consist of IMS platform, various application servers and a major upgrade/change to Rel-4 architecture MSC-Servers
- no eco-system in place yet for IMS voice/SMS roaming and interconnect (only GPRS data or CS eco-systems are available today)
- solution requires updates/changes to quite many IT systems and processes as well
Key Objectives for Voice/SMS over LTE Solution is to Re-use as much as possible of existing systems, mechanism and eco-system while avoiding proprietary extensions to 3GPP nodes
- build upon existing Rel-4 CS network and investments
- “do not touch the MSC”
- build upon fully 3GPP compliant Rel-8 EPC/LTE network
- re-use existing CS roaming/inter-connect regime
- minimise impact on UE, especially on user-interface
As a result, the simplest solution is “Voice over LTE Generic Access” or VoLGA
What is VoLGA?
- A technological approach for delivering voice and SMS services over LTE access networks
- Leverages a mobile operator’s existing core voice network
- Derived from the existing 3GPP GAN standard
What is the VoLGA Forum?
A group of companies working to…
- Leverage collective technical skills to define VoLGA specifications
- Publish proposed specifications via the VoLGA Forum web site (coming soon)
- Facilitate the easy adoption of VoLGA technology by other vendors and operators
The group is open to interested parties in the mobile community
- See http://www.volga-forum.com/ for more information about joining
The main Highlights of VoLGA are:
- Full service transparency
Supports all circuit services over LTE Supports IMS RCS and combinational services (CS+IMS) over LTE Supports handover of active calls between LTE and GSM/UMTS Supports expected LTE femtocell deployments
- Low risk, low investment
- Based on well proven 3GPP GAN standard
- Requires no change to existing MSCs and operational systems
- Conserves existing, extensive voice interconnection regime
To keep things simple, VoLGA is the best option available at the moment.
- VoLGA Forum
- VoLGA Specifications
- Voice - Bearer Aware, Bearer Adaptive or Bearer Agnostic?
- The Volga-Forum: Taking the Quest For Voice over LTE out of 3GPP
- VoLGA - reinventing UMA for Voice-over-LTE
- LTE, mobile broadband & SMS - VoLGA vs. IMS
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