Effective handsets will provide the key to market
acceptance
Internet telephony using wireless technologies such as Wi-Fi and
Wimax is still at the start of the growth curve. Nevertheless, it
offers many opportunities for corporate customers - and some
headaches for mobile operators.
When technology trends experience huge success, it can only be a
matter of time before they come together. Take voice over IP and
wireless networks. VoIP, which was a technology-in-waiting for
years, has finally gone mainstream. Products like Skype have
captured the public's imagination, while US-based VoIP company
Vonage formally opened its UK operation in May. With wireless
networking exploding in the past couple of years, using wireless
links for voice over IP calls seems like a no-brainer.
VoIP over Wi-Fi (VoWi-Fi) has potential in the enterprise WLan
as a means of reducing telephony costs while freeing employees from
their desks. But it carries even greater potential for mobile
workers wanting to make cheap calls from the growing number of
public hotspots. Analysts are starting to acknowledge the mid-to
long-term opportunities for VoWi-Fi, but there is still much work
to be done.
IT managers thinking of VoWi-Fi for their corporate
communications could benefit from dramatic cost reductions for
mobile employees, if analysts and consultants are to be believed.
Apart from savings for calls made in the UK, it offers a
drastically cheaper alternative for employees roaming outside of
their home mobile network.
"We do think there are some advantages for enterprises to move
to voice over Wi-Fi," says Jawad Shaikh, head of the Capgemini
Telecom Media & Entertainment Strategy Lab. "Our calculations
show that users could save up to 24% on their mobile bills by
switching to voice over IP via Wi-Fi."
The problem with Wi-Fi has always been convenience. Today, VoIP
calls are often made with a PC and a headset, although the popular
VoIP software client Skype is now available for the Pocket PC,
enabling Wi-Fi-enabled PDA users to take advantage of the
technology. The sweet spot for VoWi-Fi, however, will be the
introduction of cellular phones that offer both cellular and Wi-Fi
capabilities.
Dual mode handsets have been science fiction until recently, and
even now they are rare and relatively expensive, argues Shaikh.
Battery life has been the biggest barrier to the introduction of
the dual purpose handsets, argues Ian Shepherd, solutions manager
for Telindus. "Wi-Fi compared to cellular is power hungry," he
warns. "A cellphone will run for three days or a week on standby,
whereas when you're talking on a Wi-Fi phone, until recent
developments in low-power chipsets, you'd be lucky to get 20
minutes out of it."
Nevertheless, they are beginning to appear as companies iron out
the problems. British Telecom signed a deal last year with Vodafone
under which it would become a mobile virtual network operator
(MVNO). The company planned a Bluetooth-based mobile handset called
the Bluephone which would switch between Vodafone's network and
broadband VoIP using a home-based access point. The company is also
making the Bluephone Wi-Fi-friendly. Meanwhile, Motorola's Wi-Fi
phone, the CN620, is already shipping. The only snag is that it
requires proprietary hardware to work with a Wi-Fi network and
won't operate with a standard Wi-Fi hotspot. NTT DoCoMo is shipping
a more standard version in the form of its N900il device, which is
aimed at corporate users.
Wireless will make waves
Analyst company ABI Research believes the annual global sales of
dual mode mobile phones will exceed 100 million by 2010. Shaikh is
even more optimistic, predicting the same figure in 2008, which he
says will account for nearly 5% of the expected 2 billion mobile
subscriber base worldwide. By then, he argues that Wi-Fi
penetration will have reached 35% to 40% of broadband-enabled
homes, creating an even more attractive proposition for users of
the handset who can make inexpensive calls at home.
One of the biggest problems for such handsets in the short-term
is the handing off of calls from Wi-Fi networks to cellular
networks and vice versa without dropping the conversation. If a
mobile worker is making a VoIP call and walks out of the building,
it would be nice to switch automatically to the cellular service.
Gary Mead, vice president international of SpectraLink, which
supplies Wi-Fi- and Ethernet-based IP handsets for a variety of
suppliers, says that companies have a long way to go before they
address this issue. "We can see some of the trial systems that have
come out, and they recognise that it's a bit of a problem and it
hasn't been solved," he says.
For that to happen, cellular network operators must be prepared
to play ball, and yet people like Mike Short, head of R&D at
O2, seem lukewarm at best about the idea. "I'd raise questions
about what workers want to do, because it may not be the best
solution for the business," he says, adding that the company won't
talk about this with customers until 2006 at least, because the
lack of dual mode handsets makes it too early. "Jumping to dual
mode may cause complications," he adds.
But why are mobile operators acting like plumbers, looking at
seamless VoWi-Fi/cellular handoffs, shaking their heads and sucking
air through their teeth? It is because they make profits by
capitalising on revenue from circuit-switched mobile calls.
Although Short calls VoWi-Fi a complementary technology (after all,
O2 runs its own wireless hotspots), it's really a threat to mobile
operators.
Capgemini's Shaikh argues that between 5% and 7% of mobile
operators' traditional voice-based revenues will be threatened by
VoWi-Fi in 2008. "Those revenues will be cannibalised, so they will
disappear, basically. If you get voice over wireless Lan, typically
for enterprise customers, this will be basically free." The problem
is that while mobile operators could pick up those revenues by
offering subscription services to their wireless hotspots, they
could just as easily lose them to another hotspot supplier- or to
one of the burgeoning community of broadband wireless access
suppliers [see box]. Voice services still constitute the lion's
share of revenue from the 3G networks that cost the operators so
much to build, and Shaikh argues that VoIP calls via 3G data
connections are not currently viable for performance and pricing
reasons. This positions VoWi-Fi as a disruptive technology that
operators have to manage as best they can.
While the conflict between mobile operators and other VoWi-Fi
providers brews in the streets, VoWi-Fi offers some advantages
within the corporate Lan, suggests Pierre Trudeau, chief technical
officer and founder of the Colubris Networks, which sells back-end
communication products including VoWi-Fi systems.
One of the biggest advantages of VoWi-Fi in the Lan environment
is the ability to have a single mobile phone to take a call when
you are away from your desk rather than having to redirect calls to
a mobile phone even though you are in the building, he says.
Advantages over Dect
Traditional Dect phones do that, but VoWi-Fi handsets can
provide benefits that Dect cannot. "It gives you not only a voice
wireless network but also a data network," Trudeau explains. This
means that workers in a warehouse or campus environment, for
example, could tap into supply chain management systems on the same
device that they use for phone calls, thereby increasing
convenience.
Being able to tell which access point a VoWi-Fi handset is near
also carries the potential to take calls while moving around a
building. SpectraLink's Mead says that developer partners can build
location-based services into WLan phone handsets. For example,
BlueSky Wireless has developed a worker monitoring system that can
be used to plot the location of employees to the nearest access
point - useful in industries such as construction, chemicals and
oil and gas. The company will also produce bespoke software for
raising alarms and controlling stock using wireless VoIP
handsets.
Nevertheless, there are still challenges for IT departments to
overcome when implementing VoWi-Fi within the corporate WLan. For
example, device contention and quality of service are critical -
compromises on call reliability and quality will lead to rapid
disillusionment among staff. There are ways around this, says
Trudeau. His system can dynamically load balance among access
points, increasing the radio coverage of a particular access point
to take the load when one near it is running at full capacity.
There are two main standards used to maintain the quality of
service on VoWi-Fi calls. The first, the SpectraLink Voice Priority
protocol (SVP), gives priority to voice packets, but even
SpectraLink's Mead expects this to disappear in the long term as
the standards become more mature. The leading contender is the
Wi-Fi multimedia (WMM) protocol, defined by the Wi-Fi Alliance as a
quality of service protocol for voice, video, and audio
applications. Designed as a profile of the forthcoming IEEE quality
of service extensions for 802.11 networks, it is starting to gain
ground among manufacturers.
Quality of service won't do you any good at all if you move from
one wireless access point to another while making a VoIP call only
to find that your network signal drops out.
Traditionally, moving between access points requires you to
reacquire a network connection, but this will not be acceptable in
enterprise VoWi-Fi environments. Instead, companies like Colubris
have developed systems that retain the network connection at a
central point and cache wireless network access keys in nearby
access points so that the connection doesn't drop.
VoWi-Fi may still be in its early stages, and the growth will be
slow thanks to the poor availability of dual mode handsets.
However, as these handsets become more prevalent in the next 18
months, we are likely to see growing interest in the technology and
the slow but steady adoption of VoWi-Fi among mobile users.