Tuesday, February 1, 2011

The State of Voice over Wi-Fi

I recently read this article on PC World by Jason Kennedy, "Wi-Fi Calling: T-Mobile's Unused (So Far) Ace in the Hole", which got me thinking about the overall state of Wi-Fi calling in general.

Here's how I see the Voice over Wi-Fi (VoFi) landscape right now:

Enterprise VoFi
A broad array of product offerings are available, including Polycom (SpectraLink), Cisco, Avaya, Microsoft, Vocera, and others. The overall state of IP-PBX deployment is fairly broad and definitely mature. At this point, I would hard-pressed to find a medium to large enterprise that hasn't begun a migration from analog TDM or digital voice to a VoIP solution. Hospitals seem to be the standout industry, deploying Vocera badges for hospital staff like crazy.

At the lower end of the spectrum, SMBs, educational institutions, and many small state and local government entities are probably still running off fairly old (ancient?) analog / digital systems. But hey, with minimal budgets they have to prioritize and I can't fault them for not wanting to spend money on replacing a working telephony system that probably cost them a fair penny in investment on a PBX or key system.

Voice over Wi-Fi adoption is not as widely deployed and is commonly seen as a nice addition to an existing VoIP network, but not an immediate requirement. As user mobility within the enterprise increases, especially with broader consumer demand of desk phone portability (laptop soft-phones, tablets, dual-mode phones), VoFi adoption can be implemented fairly easily once the leap to VoIP has been made. The largest hurdle facing most deployments will be proper WLAN design for VoFi, which may require adding experienced wireless engineers to the staff or hiring out the work to a 3rd party integrator.

Cellular / Telco VoFi
The long-hyped FMC (Fixed Mobile Convergence) that would allow seamless voice call hand-over between Wi-Fi and cellular networks is still not widely deployed. Only minor installations with well justified business benefits and ROI have seen adoption. The good news is that this slow-start has allowed the technology to mature, and it is remarkably ready for broader enterprise use.

T-Mobile has clearly been the leading telco adopter of VoFi with their UMA solution for enterprises. Additionally, support for consumer deployments came with their Hotspot@Home feature back in 2007. At $10 a month, it was a steal for consumers needing additional coverage in weak cellular areas, needed to reduce used minutes, or used a very large number of minutes each month. And it worked pretty well. However, support was fairly short-lived and the feature was canned last year in April 2010.

However, their back at it, having recently announced a partnership with Cisco to  provide seamless voice roaming between enterprise Wi-Fi networks and cellular networks. And at their Investors Day in January they announced that all of their Android and Blackberry smartphones support Wi-Fi calling. It's still unknown if other U.S. carriers see T-Mobile's Wi-Fi / UMA service offering as a threat and will follow suit with FMC solutions. However, support of Wi-Fi in general by cellular carriers is definitely growing exponentially, with Verizon and Sprint offering portable 3G/4G Wi-Fi hotspots and AT&T deploying managed Wi-Fi hotspots wherever it can ink a deal (and pick corporate pockets?).

Consumer VoFi
On the consumer side, offerings have been out on the market for a while. Skype has been the primary adopter in this space, having partnered with La Fonera as early as 2006 to offer Wi-Fi calling. Vonage also offers limited support for Wi-Fi calling, but has been hampered by poor financial performance preventing broader investment in the solution.

Newer entries into this space have been provided by smartphone application developers taking advantage of advanced feature capabilities of newer Apple and Android smartphone operating systems. Line2, Fring, and Talkatone are all examples of apps that make VoFi calling on smartphones a reality for incredibly cheap, especially when paired with VoIP services such as Google Voice or Skype.

However, mass-market consumer awareness of such options still remains thin. Adoption has been limited to tech-savvy consumers or individuals stumbling across such services while researching foreign travel options.

My Take on VoFi
Enterprise VoFi is mature and poised for mass deployment. Enterprise IT departments have wrapped their arms around VoIP networks over the last decade, and extension of VoIP onto the Wi-Fi network will require minimal effort. However, proper WLAN design, testing, and verification should not be overlooked, as traditional wireless data network deployments are often ill-suited for VoFi. The push by employees for greater mobility and desk phone portability will also drive demand for VoFi.

Carrier FMC voice hand-over between cellular and Wi-Fi is maturing rapidly and ready for broader use. However, business justification and clear ROI for most organizations is still hampering its adoption. Don't expect this to change overnight. It will be interesting to see if real-time video calling (such as Apple's FaceTime) will have any impact on enterprise FMC adoption. We'll just have to wait-and-see.

Consumer VoFi solutions are available for individuals savvy enough to take advantage of them, and they can save a few bucks doing it by shaving cellular bills. They can also gain better voice quality and coverage inside homes and locations with poor cellular reception. However, until a major proponent of Internet voice service with a user base that can bring their solution to the forefront emerges, adoption will remain limited. Watch for newcomers to differentiate themselves from traditional telco landline and cellular providers by offering a broader set of features and controls for consumers. Google appears to have all the pieces to make this happen, if it chooses.

Let's not forget that the adoption of 802.11n Wi-Fi is already playing a part in these solutions, offering better network performance and rapidly changing the perception of Wi-Fi capabilities.

I'd love to hear your feedback on VoFi adoption.
  • What is your organization doing with VoFi for internal calls?
  • Has your organization explored FMC? What decision points justified (or failed to justify) FMC deployment?
  • What are you doing as a consumer with VoFi? Anything?


  1. Andrew,

    This is a good roundup of the options available. I agree with the categories, and I think it's the motivations which are important.

    Enterprise VoFI – is primarily about getting those costly mobile calls off the cellular network and onto the ‘cheaper’ PBX (ie fixed network). In this case, the PBX remains the hub for calls when in the office rather than calls going directly over cellular. PBX vendors need to continue to innovate, and this is one hot area. Originally this was positioned as a cost saving for IT managers, I’m not sure it that actually proved out. There’s a fair bit of effort to get PBX extensions onto smartphones.

    Cellular VoFi – is primarily about routing cellular service over Wi-Fi for the purpose of better indoor coverage and in some cases cheaper calling. As you mention, T-Mobile is the leader in this in the US with their Wi-Fi Calling service. T-Mobile did drop the $10/all-you-can-call consumer offer, but for enterprises with more than 100 phones, T-Mobile actually introduced *free* wifi calling. This is a HUGE cost savings for enterprises. Any calls made over Wi-Fi would not count against the corporate bucket of minutes. Kineto developed a case study about one enterprise with 1,500 blackberries that ended up saving about $400,000/year in mobile expenditures.


    Consumer VoFi – this is the alternative to using the fixed network (enterprise) or mobile network (cellular) for calls. Rather than using the traditional (and presumably expensive) incumbent fixed or mobile operator, go with one of these over the top VoIP players. Kineto conducted a survey of people who use VoIP applications on their smartphones, and nearly 90% of the use was to place international long distance calls. It was decidedly NOT for daily use.

    To wrap up, I’m not sure how much cost savings is available to IT departments doing an enterprise solution. Today enterprise VoFI seems to be more about soft benefits. For those using T-Mobile, there is clearly an opportunity to save on cellular costs with Wi-Fi calling.



  2. Hi Andrew,

    T-Mobile's UMA solution works quite well from what I've seen, though I'm not sure it's impact on things such as battery life or bandwidth consumption.

    Unfortunately for users, there is much debate and churn in the cellular wireless industry about the best way to handle voice over next-generation cellular networks, especially LTE. Here is an article from last fall on the topic: http://urgentcomm.com/networks_and_systems/news/voice-lte-moves-forward/

    For the enterprise, 802.11n is certainly playing a large role in enabling voice over Wi-Fi. One of Meraki's goals is to enable the rollout of enterprise 802.11n and make it as easy to deploy and manage as possible.

    As a consumer, I have good-enough cellular coverage at home that I haven't looked for a voice over Wi-Fi solution.


  3. I read this whole post regarding latest technology of The State of Voice over Wi-Fi. Its such a very informative and also interesting post because in this post each and every topics regarding latest technology such as My Take on VoFi, Consumer VoFi, Cellular / Telco VoFi, Enterprise VoFi and many more. SO thanks for share this valuable post.