Pros and Cons of Dual-Mode Cellular/VoWi-Fi Mobile Phones

I recently purchased a BlackBerry 8320 Curve from T-Mobile, and of all the device’s features, I have one clear favorite: Wi-Fi. More specifically, I love its voice-over-Wi-Fi (VoWi-Fi), or voice over wireless local area networks (VoWLAN), functionality.

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My new BlackBerry’s not the first Wi-Fi-enabled smartphone I’ve used, but it wasn’t until a couple of weeks ago, when I moved to an area with less-than-stellar network coverage, that I fully realized the benefits of dual mode cellular/ VoWi-Fi phones, or phones that can use both cellular and Wi-Fi networks for voice calls.

The first call I tried to place in my new home via cellular network dropped a minute or so after it connected. But after I setup my wireless network and switched on my Wi-Fi, my call quality was great. I’ve heard people complain about the quality of VoWi-Fi and other forms of voice over IP, and occasionally I get some static when I use it, but, all and all, I’ve been very impressed with the audio quality. That could be because I’m employing a Linksys router (802.11b, g) that’s specifically meant for use with T-Mobile devices.

One issue I’ve had with VoWi-Fi on the Curve is switching back and forth between my personal wireless network and T-Mobile’s EDGE network. The carrier says the transition should be seamless, but about half the time I drive out of range of the Wi-Fi, my call gets dropped.

Currently, T-Mobile’s the only major U.S. carrier that enables VoWi-Fi functionality in its devices—at least without the use of unauthorized third-party apps. Other carriers like AT&T offer phones with VoWi-Fi capabilities, like the popular BlackBerry 8820, but they don’t currently ship them with software that permits VoWi-Fi connections.

I mentioned that the Curve 8320 is not the first device I’ve used with Wi-Fi. A while back, just after RIM released the BlackBerry 8820 on AT&T, I got one from the company for review, only to find that I couldn’t use it for VoWi-Fi—a huge disappointment, especially since I’d recently touted the device and VoWi-Fi in a blog post, and I wanted to give it a test drive.

So I started doing some research and found that many carriers are a bit hesitant, to say the least, to embrace VoWi-Fi. That’s largely because they fear their customers will increasingly employ wireless hotspots instead of paying for the use of their cellular networks. T-Mobile has decided to embrace the technology and is, in effect, using it as a competitive advantage—while charging $10 extra a month for its HotSpot@Home Talk Forever Mobile service, which offers unlimited VoWi-Fi calling from home or in range of another T-Mobile Wi-Fi network.

And other wireless carriers may soon change their tunes as consumer and enterprise demand for the devices increase. The benefits of VoWi-Fi to consumers are clear from my experience noted above.

And a while back, I spoke with Allen Nogee, principal analyst with market research firm In-Stat , who told me VoWi-Fi phones offer two main benefits to CIOs and their enterprises: control and cost.

“Businesses give you your phone, but then they lose

control of it. You can call anyone and they can’t stop it,” Nogee said. “These [voice-over-Wi-Fi] phones let them get control back when users are in the building, and they save money on cellular charges since most calls are made in the building [using the corporate network].”

An In-Stat survey from last year found that of the 1,400 some-odd “mid-to-high income [American] businesspeople familiar with technology” surveyed and who own a mobile phone, nearly half who planned to replace a phone wanted Wi-Fi support in their next handheld.

And ABI Research predicted there will be “well in excess of 300 million” dual mode handsets in use throughout the world by 2011.

Do you use a VoWi-Fi-enabled device? If not, do you, like the businesspeople In-Stat queried, plan to make Wi-Fi, and more specifically VoWi-Fi, a priority when you upgrade your smartphone?

Are your general impressions of VoWi-Fi in line with mine? What do you think are VoWiFi’s pros and cons?

AS