• 10/29/2015
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WiFi Calling In The Enterprise

With WiFi about to take off, enterprises can look forward to improved indoor calling, but they need to prepare to support it.

In my last post, I described what WiFi calling is and the benefits it offers. I also looked at some of the issues it may pose in the enterprise. In this post, I’ll examine ways that enterprises can prepare for the adoption of WiFi calling.

WiFi calling has a lot of potential in the enterprise, where some employees no longer hand out their landline numbers to associates or include them on business cards, and are increasingly relying on solely on mobile phones. Yet at times they have to pace about in parking lots (sometimes in the rain) or cluster by windows just to get a signal. Other times, they suffer through dropped calls or jittery voice quality.

However, while some may view WiFi calling as an almost free solution that solves indoor calling problems at little to no cost by leveraging existing infrastructure, it’s not that simple. Here’s why:

  • If WiFi calling becomes a widely used, demands may be placed on the networking team to improve call quality. However, WiFi network admins are already wrestling with BYOD, hyper-location services, bandwidth waste by YouTube users, neighbors with unauthorized access, and other firefighting tasks. They don’t need another reason to bring out a RF or network analyzer. Many wired VoIP networks are kept on a separate network for a reason, and voice traffic can be separated using VLANs or prioritized appropriately.
  • WiFi calling may increase capex if additional WiFi devices are provisioned for more signal coverage, adding additional opex if special tuning is required for voice data prioritization, and some process changes are needed if the network admins are called for support whenever there is a perceived voice quality problem. An IT team may be set up for supporting wired standard desk VoIP phones, but who will support voice call quality from handsets that may be on either WiFi or the mobile network?

There are a couple paths enterprises can take to prepare for WiFi calling: Improve traditional WiFi networks, or look to mobile operators to assist with indoor coverage.

Boost WiFi networks

Improving the traditional campus networks to support WiFi calling is a path many enterprises will choose. It’s cost effective and will leverage existing infrastructure.

Makers of WiFi APs support Voice over WLAN and some capabilities can be repurposed to support WiFi calling. For example, Aerohive APs have voice QoS settings, Aruba has AppRF packet classification settings, Cisco Aironet has the ability to separate voice traffic to different VLANS, and Ruckus has voice QoS using its SmartCast technology.

Figure 1:

(Image: Squaredpixels/iStockphoto)

Some of these solutions were created to work with traditional VoIP phones or apps like Microsoft Skype for Business. Therefore, WiFi calling may require additional investigation or collaboration with networking or mobile vendors.

In addition to adjusting WiFi AP settings, the rest of the network path, such as campus switches, need to support the traffic as well, so campus switches may require examination for updating or reconfiguration.  

Work with mobile operators

Mobile carriers and equipment makers offer enterprise-grade indoor mobile coverage solutions for building owners, malls and campuses. Here are some options:

  • Consumer-class signal boosters or routers: Not appropriate for enterprise offices, but may be useful for work-at-home users.
  • Femto cells: These are consumer devices that create a small mobile coverage area and take the voice and data out to the carrier via broadband. It may be acceptable for small businesses connecting a handful of designated users (often a dozen or less), but for wider coverage, enterprise class solutions are needed.
  • Pico cells: Mobile base stations provided by mobile operators to improve coverage within the office and connected to a controller, which in turn connects to the mobile network.
  • Distributed antenna systems (DAS): Comprised of rooftop antennas that spread the mobile signal through a large area via indoor antennas. Although expensive, the benefit is that it is transparent to the endpoint device. This makes sense for improving indoor coverage at airports, train stations or shopping malls. It can be carrier neutral, but the system needs to deal with many combinations of technologies such as LTE, CDMA or UMTS.

One enterprise solution, the Ericsson Radio Dot System, is designed for installations smaller than a distributed antenna system but larger than a pico cell. It distributes a cell signal in an office floor from a central base station via network cables, which also supply power using Power Over Ethernet. Some enterprise WiFi access points, such as the Cisco Aironet 3600, can accept 3G small cell modules as well.

In the future, there will be more technologies available to combine the capabilities of WiFi with mobile (LTE) to provide better service, such as LTE+ WiFi Link Aggregation. I look forward to those developments to create a clean solution that leverages both networks.


WiFi Calling

If WiF calling becomes a widely used, demands may be placed on the networking team to improve call quality. However, WiFi network admins are already wrestling with BYOD

This is one of the key point author has mentioned, but to my analysis i guess we already have high demand for improving call quality via Wifi calling. End users are interested in using this service towards cost saving.

Re: WiFi Calling

Virsingh, In the US, many end-users have unlimited minutes, so cost savings will not happen for many. However, WiFi calling may reduce roaming charges if people travel internationally.  But there are people and places that py or charge per minute of call, and WiFi calling will save money.

People definitely do want WiFi calling to improve call quality.  Many new buildings designed to save energy usage are not good at letting mobile phone signals indoors, so people will be concerned more in the future.

For people who manage buildings, WiFi calling will save monery compared to setting up specialized equipment, but one must remember that just because you already have WiFi does not mean the benefits come at no-cost -- i.e. one may need to tune or add more APs.

Re: WiFi Calling

And, of course, even not internationally necessarily.  There are parts in the US, for instance, where cell phones become unusable without incurring roaming charges because of the proximity to the Canadian border.

Re: WiFi Calling

Joe: I had forgotten about that.   It's very inconvenient to set your phone to not roam to always look for the roaming indicator.  I presume the same occurs close to Mexico.  

Re: WiFi Calling

Yep, probably.  I'm a New Englander, so my experiences are informed thusly -- specifically, travels to Vermont and having to put my phone into airplane mode accordingly because of proximity to Canada.

Re: WiFi Calling

@don_conde, agreed. If an organization is serious about communication then, as a primary concern the WiFi infrastructure of an organization should receive an upgrade or at least an evaluation so that future demand can be met. 

It would nice if WiFi and LTE resources could be utilized together to gain the maximum benefits. Currently, Android has a Download Booster function that combines WiFi and LTE to download files that are larger than 30MB. I guess with voice and video, latency introduces a new dynamics into the equation that is causing the technology to not be utilized for voice at the moment but, developers will soon find a work around to it. 

Re: WiFi Calling


re: It would nice if WiFi and LTE resources could be utilized together

Good point. That's is what LTE Wi-Fi Link Aggregation aims to do.   That will benefit everyone.  With the current system, handover from one to another probably won't work well.  With this, the two links are coordinated.



Re: WiFi Calling In The Enterprise

I didn't realize this would be following so closely on the heels of part 1 - you definitely present a believeable vision of the future, Dan, where WiFi calling is integrated seamlessly in a larger package the has the enterprise network, AP vendors, and cell carriers working together to make sure everyone is always connected. I still think in the immediate feature, the opex cost is more likely than the capex - are people really going to invest in infrastructure just for WiFi calling? Probably not. But might they be fielding plenty of user calls on the matter whether they like it or not? Likely yes. Good point about VoIP specialists who aren't quite prepared being saddled with this burden. 

Just to be clear on these indoor mobile coverage solutions - do these work with the WiFi calling feature cell carriers are rolling out, a seperate technology designed to offload the traffic onto the corporate network and then move it to the carrier, or just an extension of the carriers network into the building? It sounds like it may be a mix of all three. Whether or not these impact Wi-Fi calling directly, they're definitely a part of that comprehensive vision of networks working together which, as you rightly point out, is a moving target still in progress as we speak.

Re: WiFi Calling In The Enterprise

Zerox203:  The various wireless AP's with QoS settings (that identify voice traffic) will work with the WiFi calling features that carriers are rolling out.  

It offloads the traffic to the corporate network, which reaches in to the mobile carrier's core network for handling the rest of the path for the call.  This is possible now that the telco's have modernized their internal network.

The small cells (Femto, Pico) extend the carrier's network into the building via an IP network. So the phone connection uses the telephone radio band, not WiFI.  The small cells are mostly carrier specific and handle only a few callers.

One item that I briefly referred to is a pre-configured WiFi hot-spot for home use -- it's basically a WiFi AP that is optimized for voice calling. It's a consumer grade AP that has a T-Mobile label called WiFi Cellspot and that uses WiFi calling. OK for home office, but not for work.  

DAS is often not carrier specific. It's an antenna system that will extend signals.  It's an industrial strength version of a signal booster.  Big buildings may use them and they work well, but can be expensive.  Red Dot is a system that is like a DAS but meant for smaller scale.

What I was trying to get at is that as people demand good indoor coverage, one should not just focus on WiFi calling, and figure out out how to make calling work via different methods.  

WiFi is part of the equation for improving indoor calling and it's a good path to look at.  One may be lucky and the existing WiFi infratructure can magically work out to route WiFi based mobile calls.

I was concerned that people would say "Wow! I can make regular cell phone calls indoors via WiFi, and I don't need to do ANY extra work".  I think that's not true. You may need to tweak APs or add more APs.  Voice traffic differs from regular data traffic since it's so sensitive to latency and jitter.

I'm also saying that we need to be aware people have often unrealistic expectations. (I think you and I already know that)  I heard of people complain about lack of cell coverage deep in an underground garage.  So they may run to IT and say: "I have my WiFi calling on my iPhone and my voice sounds terrible. Please fix it for me".  Are they also in the garage, far away from any AP?  It can be any number of problems.  Just because they can get a few WhatsApp messages doesn't mean they can do continuous phone calls on the same WiFi network.  Plus hand-off from WiFi calling to mobile network (let's say a person walks outside WHILE talking) is not going to work in most cases.

Finally -- you make a good point about people not willing to pay Capex for WiFi calling. They are likely going to push that responsibility to IT to "just fix it", hoping that a few config settings will make it all fine. 

wifi requirements

Does wifi calling need LTE supporting mobiles or SIM cards?

Re: wifi requirements

The phone and the carrier need to support it. For the phone it is typically the ROM and software loaded on it, which means that the phone is usually the one purchased from the carrier, so unlocked phones usually don't work (rather frustrating since unlocked Android phones SEEM to support it but it won't properly register to the carrier network via WiFi).

One exception seems to be iPhone (recent ones) which is compatible as shown on their web site specs to work across several multiple carriers. I don't think LTE is a requirement, since the voice gets carried by WiFi. As for SIM card, I think they are independent of this issue. Best thing is to ask the carrier. If you are in the US, most major carriers support it.