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Back in 1999, when 3G was still a questionable dream, IMS started to take root as an architecture for mobile services. It was adopted by the 3GPP and later on also by 3GPP2 and other organizations and forums. Standardization work went on for many years resulting in continuous releases of standard versions forcing vendors to enter a cat-and-mouse game.
The adoption of IMS was slow and disappointing
There are many IMS deployments today but IMS didn’t deliver on its promise. While vendors and service providers were busy fighting in the standard bodies, small start-ups came quickly to the market with advanced services and took the market by storm.
So what is all the fuss about VoLTE?
The answer to that lies in the eyes of the beholder.
LTE networks are being deployed by hundreds of service providers worldwide. Once LTE coverage is ubiquitous, there is a lot of sense for the service provider to move away from circuit switched (CS) voice to VoLTE, as in a few years it will eliminate the need to continue supporting the CS network, thereby reducing OPEX.
Additionally, higher quality end-to-end voice will be possible as VoLTE supports HD voice and includes features for resource reservation as well as other important features such as security.
From the end user perspective, in addition to the higher quality voice and security that comes with VoLTE, longer battery life will be possible as the need for dual LTE & CS connectivity of the phone will be removed.
Learning from the past, there are 3 fundamental challenges service providers and vendors will need to solve.
Time to market
Service providers have waited for technologies to become stable and for standards to become fully ratified. This stopped them from launching advanced services, leaving the door open for OTTs.
The reality is that service providers currently providing VoLTE services are not all doing so the same way. Different capabilities and scenarios are supported by each service provider. This results in the need to verify each device and server before it is deployed on their network and vendors are required to make modifications in order to pass this certification process. Given this reality, there is a need to have a mediation element (SBC) between service providers, thus interoperability is theoretical… (did I say there is no point in waiting for everything to be perfectly compatible and ready?) Launch…don’t wait.
There are other networks out there
The service provider world is more complex than that of an OTT. The service provider doesn’t have the benefit of building an island. It needs to connect to older networks, enterprise networks and other service providers. This again brings up the need for that demarcation point that will mediate signalling and make sure voice quality between those networks remain good.
Speaking with service providers that are already invested in VoLTE and interconnecting with other networks, voice quality and QoE are their main concerns. Solutions for these concerns are provided through advanced audio processing done in mediation entities that interconnect between the networks.
Stay tuned for more on QoE in future posts on this blog.
Why is this important?
There are different opinions about the future of VoLTE and its chances to succeed. There is no doubt that secured voice calls using HD codecs are possible today using OTT. It is also clear that an OTT will not go this route, but in the service provider space VoLTE looks like a technology that will happen because:
- It makes sense from an operational cost perspective
- VoLTE integrates nicely into the service provider’s existing OSS/BSS systems
- There are ways to downgrade the call to 3G/TDM when LTE is not available…SRVCC
Having said that, interoperability is a challenge. Service providers should assume there will be no 100% interoperability and standard support both on phones and servers. Certification of clients will always be required as well as demarcation points between networks as exist today in their VoIP networks.
Therefore time to market is more important than completing every item on the standards checklist.