OnQ Blog

Evolving your voice – VoLTE, WCDMA+ and more

Jul 10, 2012

Qualcomm products mentioned within this post are offered by Qualcomm Technologies, Inc. and/or its subsidiaries.

Quick question for you—what technology do you use when you make a voice call on your shiny new 4G LTE smartphone? Answer - 3G, and in some cases even 2G!

Surprised? LTE is currently a data-only service, meaning, whenever LTE users make a voice call, the device falls back to the local 3G (or 2G) network, and places the call. And it will be so, for some time to come!

If you are wondering “why?” and “how?”—well, you have come to the right place! Read on to understand the Voice Evolution that is currently underway.

In the long-term, the industry is moving toward packet-based, rich-voice, referred to as VoIP (Voice over IP), which brings exciting voice services such as integrated-presence and multimedia sharing during voice call, video telephony and many more. VoLTE (VoIP over LTE) and VoIP over HSPA+ and EV-DO enable operators to offer these much-desired services and create new revenue opportunities.

A key point during this long transition is the extended lifespan of today’s traditional circuit-switched (CS) voice services. CS voice, characterized by its excellent-quality, reliability and ubiquitous global coverage, continues to evolve and increase its efficiency. The main benefit of this increased voice efficiency is its ability to free-up resources for rapidly growing data services.

1X Advanced, the next step for today’s CDMA2000 1X networks almost quadruples the voice capacity, freeing up almost 3/4th of the spectrum for data services. No wonder there is a lot of operator interest in 1X Advanced, including major operators such as Sprint.

Similarly, WCDMA+, which is the next step for WCDMA, triples voice efficiency, thereby freeing up resources for data (up to 2/3rd of a 5 MHz carrier). With 2 billion HSPA+ subscribers projected to be using WCDMA for voice in 2015, the decision to evolve the networks to WCDMA+ is a no-brainer for most HSPA+ operators.

Now, coming to VoLTE, as is the case when bringing any new technology to market, VoLTE will be deployed in phases, which means that when users move out of the LTE coverage area, VoLTE calls will have to be handed off to CS voice. In that scenario, a feature called SRVCC (Single Radio Voice Call Connectivity) comes to the rescue, making the handoff from VoLTE to CS voice seamless, reliable and transparent to users.

As mentioned above, the main attraction of VoLTE is its ability to offer rich-voice services, but when calls hand off to CS, only voice is moved over, not the other services. This means, operators have to evolve their networks to VoIP over HSPA+/EV-DO in parallel to VoLTE to offer rich-voice services ubiquitously across all of their coverage area.

Qualcomm (the company responsible for innovating 1X Advanced and WCDMA+) is now leading the voice evolution, spearheading the development of VoLTE and VoIP over HSPA+/EV-DO. Moreover, we demonstrated the world’s first SRVCC hand-off between VoLTE and 3G voice with Ericsson in Feb 2012.

If any of this is confusing to you, here’s the bottom line on voice evolution: 

  • For now: CS voice 
  • In the near future: VoLTE with SRVCC
  • In the long-term: Full VoIP with VoLTE and VoIP over HSPA+/EV-DO
  • Along the way continue to evolve and increase efficiency of CS Voice with 1X Advanced and WCDMA+

If this piques your interest and you’d like to know more, please visit our webpage www.qualcomm.com/voice_evolution.

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Opinions expressed in the content posted here are the personal opinions of the original authors, and do not necessarily reflect those of Qualcomm Incorporated or its subsidiaries ("Qualcomm"). Qualcomm products mentioned within this post are offered by Qualcomm Technologies, Inc. and/or its subsidiaries. The content is provided for informational purposes only and is not meant to be an endorsement or representation by Qualcomm or any other party. This site may also provide links or references to non-Qualcomm sites and resources. Qualcomm makes no representations, warranties, or other commitments whatsoever about any non-Qualcomm sites or third-party resources that may be referenced, accessible from, or linked to this site.

Prakash Sangam

Director, Technical Marketing

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