All of the hubbub about Long Term Evolution (LTE) during the past couple of years has been about data. Voice, to date, has not been part of the 4G LTE experience.
That is about to change. The vendor and service provider industries are on the cusp of introducing voice to the platform, which has established itself as the next phase in cellular communications.
Light Reading reports that Verizon Wireless plans a Voice over LTE (VoLTE) rollout across its U.S. footprint in 2013. The story quotes an analyst as saying the carrier is conducting trials in two cities now. The story said that the carrier's previous statements that it will launch VoLTE in 2012 are not necessarily inaccurate since they made no reference to a nationwide move.
Bringing voice into the LTE fold is a significant technical step because verbal communications is far more demanding than most forms of data (it's actually all data, but voice is a specialized version).
It's not just a North American phenomenon. In a Telecoms.com interview before next month's Middle East and North Africa LTE Conference, Dr. Mohamed Nadder Hamdy, the director of planning for mid-eastern Internet hub Etisalat, discussed his company's approach, which relies on the Internet Multimedia Subsystem (IMS), a platform for integrating cellular and IP networks.
The scheme we are adopting for VoLTE is the IMS solution, and that is not yet ready. It will take some time. The terminals also need to be IMS ready. A possible solution will be circuit-switched fall back, where the terminal will revert to 3G to make a voice call-but we don't want to go that route; we want to go directly to the IMS part, which is recommended by the 3GPP and all the industry.
This week, various reports, including this one at CNET, said that Qualcomm and Ericsson have taken what they call a major step to VoLTE. Though LTE networks increasingly are common, they are not in all cases contiguous. Thus, sessions must be able to roam between LTE and 3G systems as users move.
The two vendors have successfully completed a call using Single Radio Voice Call Continuity (SRVCC) to switch a voice call between an LTE and wideband code division multiple access (WCDMA) network using Qualcomm's S4 MSM8960 3G/multimode processor. The switch is possible for non-voice data calls via previously developed circuit-switched fallback (CSFB) technology.
Mavenir Systems announced this week that it has four core VoLTE-capable networks available in the United States and one in Western Europe. Look for more news-a lot more-as the entire chain, from service providers to test equipment makers, get going on VoLTE in earnest.