Qualcomm and Ericsson demo a Voice over LTE call successfully handing off to WCDMA

Ever wonder why smartphones with 4G LTE connectivity have such terrible battery life? The answer is rather simple. While most phones usually have only one cellular radio on at the same time, devices using 4G LTE need to have two radios on simultaneously. One of those radios, the one that does that 4G LTE, can only really do data. Voice and text messages are sent over a second cellular radio that connects to a legacy 3G network. Now this is solely the case on Verizon’s network, with AT&T things go a bit differently. When you’re about to get a call on AT&T’s network your device switches from 4G LTE to 3G using a technique called Circuit-Switched FallBack, CSFB for short. In a perfect world everything would go over 4G LTE, meaning voice, texts, and data, which is why Voice over LTE, VoLTE for short, was invented. Problem with VoLTE is that it works great when you’re in an area with LTE coverage … but what happens when you can only connect to a 3G network?

That’s where Qualcomm and Ericsson come in. Late last year, just two days before Christmas, Ericsson setup a test network to evaluate Single Radio Voice Call Continuity, SR-VCC for short. Using a device that had a Qualcomm Snapdragon S4 MSM8960 inside, the two companies successfully placed a call using VoLTE and then made a hand off to a WCDMA network.

Long story short, the folks at Qualcomm and Ericsson have proven that they can build a device that will connect to both next generation networks and legacy networks, but not have to connect to both at the same time. What does this mean for you? Better battery life, which translates into a better user experience, and who knows, maybe even devices that are thinner than what’s out on the market today!

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