A MARRIAGE OF CONVENIENCE: WHERE Wi-Fi & MOBILE MERGE

With apologies to Frank Sinatra, mobile data and Wi-Fi are like strangers in the night, exchanging glances, wondering in the night, what were the chances? Despite their starkly divergent evolutions — the long and often meandering public network sponsorship of mobile data, compared with the rapid grass-roots rise to popularity of Wi-Fi — the idea of converging the two wireless technologies to broaden customer choice and encourage seamless networking is a seductive notion. Yet for these would-be paramours, there are no easy solutions to reach an embedded technical integration of the networks on which they are based.

The good news is that when mobile and Wi-Fi signals overlap, customers increasingly will be presented with a simple menu outlining a variety of services. Their own device interfaces and sniffer software programs will give them control to choose and even prioritize choices for backup networks.

In fact, despite the dearth of devices and network gear that incorporates both mobile and Wi-Fi protocols — factors integral to true, seamless network handoffs — solutions have surfaced in recent months that allow users to navigate the administrative steps of roaming across these networks. The initial ingredient in that administrative roaming is carrier interest in — and willingness to present — a combined offering to their users, either by owning Wi-Fi hot spots or partnering with hot spot operators or aggregators.

Just a few years ago, it was unimaginable that carriers would be willing to bend to the Wi-Fi trend. Most viewed wireless LANs as competition that their slow-to-emerge data services eventually would have to overcome. And after committing millions of dollars each to 3G network upgrades that looked to be years away from returning on the investment, Wi-Fi hot spots were like a growing swarm of mosquitoes buzzing about the patio deck while carriers were trying to take in a long-range view of the horizon.

That all changed in late 2001 when carrier giant T-Mobile acquired bankrupt hot spot operator MobileStar, which had an exclusive arrangement to operate hot spots in Starbucks coffee shops. “The consensus now is that there should be further integration. The threat is over,” said John Baker, CEO of Transat Technologies, a developer of network mediation solutions. “Carriers see the benefit of integrating Wi-Fi spectrum into their service strategies.”

It's not happening yet. But for T-Mobile, the first step is about to occur. A company spokesman said T-Mobile will allow seamless administrative roaming between its GPRS, EDGE and 802.11 network coverage areas during the second half of this year. “We'll create one bill by adding the hot spot service to our mobile bill,” he said.

There are other compelling reasons for carriers to work toward integrating Wi-Fi with their traditional offerings. “Carriers are very interested in this because it is basically free spectrum in Wi-Fi,” said Mark Morell, director of strategic marketing for wireless at Nortel Networks. “Some people say the companies that integrate Wi-Fi will have the best advantage. They can augment their own spectrum with Wi-Fi, and continue to own the users as they travel inside or onto Wi-Fi networks.”

T-Mobile, which was the first traditional mobile carrier to get into the Wi-Fi business, owns its hot spots. But it appears that other mobile carriers getting into the Wi-Fi market will do so via partnerships with established players, rather than hot spot ownership or buildout strategies.

“Because prices for equipment and devices are so low, the installed base of hot spots is growing very fast,” said Sky Dayton, founder and CEO of Wi-Fi aggregator Boingo Wireless, which currently counts about 1200 hot spots across the U.S. This installed base is broadly fragmented and also includes notebook PC manufacturer Toshiba, which recently unveiled a plan to build thousands of its own hot spots; T-Mobile, whose Starbucks hot spots number about 2200; and companies such as Wayport, the nation's largest independent hot spot operator with about 2500 sites on the hotel and airport circuit.

Other large providers, free community hot spot networks, as well as mom-and-pop operators that may own only a few hot spots at most, further this fragmentation. Such a confusing environment — compounded by the ease with which virtually anyone can become a hot spot operator — could keep even first-tier carriers from becoming dominant hot spot operators, which Dayton said is the certainty they would need to make the new business worthwhile.

In one of the clearest examples of mobile/Wi-Fi partnerships, AT&T Wireless is teaming with Wi-Fi operator Wayport to resell Wayport's 802.11 network access in hotel lobbies as a new AT&T data brand, Go Port. Significantly, AT&T Wireless is letting its customers choose to switch off its network and use wireless LANs that offer much higher bandwidth than the carrier's current mobile data offering can match. In effect, AT&T Wireless is giving up control of network access and reliability, but not its influence on the customer.

The second piece of the administrative roaming puzzle is a front-end system that actually tells users what kinds of network signals are available to them in a given location. Traditional Wi-Fi sniffer software helps users find hot spot signals and often identifies locations in which multiple Wi-Fi hot spot signals overlap.

Most existing sniffer software can't track mobile data network signals, but that's about to change. Boingo recently unveiled a new version of its sniffer software that identifies hot spot signals and can present Wi-Fi users with a choice of hot spots to access where signals overlap. Though it doesn't support mobile data services yet, Dayton said that same software will soon be able to detect signals from 2.5G and 3G GSM/GPRS, CDMA 1XRTT, EDGE and iDEN mobile networks. The software will let users view a variety of available signals, as well as signal strength.

Does that mean users will be able to prioritize network choices based on their own preferences, service prices and packages, or service providers? “Totally,” Dayton said.

He added that Boingo has been working on its latest software version for about six months to create multi-network sniffing capabilities. But there are also many other Wi-Fi sniffer programs on the market, and it's likely that multi-network sniffing capability will eventually become a commercial standard.

Another necessary client-side element for roaming are the PCMCIA cards or integrated radio interfaces that would allow notebook PC users to access both types of networks. Several vendors have already accomplished this. Bosco Eduardo Fernandes, chairman of the information and communications technology working group at the UMTS Forum, stated in a recent research report that, though not yet in wide commercial use, “the expectation is that a GPRS/3G/WLAN card would draw a larger user group.”

Dilithium Networks has developed a technology concept called unicoding that takes much of the complexity and cost out of normal transcoding that occurs in networks between standards — such as GSM/GPRS, W-CDMA, 802.11 and even IP voice protocols like SIP, H.323 and H.324 — supporting different services and devices.

Also, at the network administrative level, there are SS7-based servers and software programs — made by the likes of Nortel, Transat, Intec Telecom Systems and Intellinet Technologies — that can act as visitor location registers on GSM/GPRS networks. They can communicate with existing SIM cards in 2.5G devices, authenticate these users on either the mobile data network or publicly operated wireless LAN, and arrange a single bill for sessions on both networks.

“You can have real-time authentication going on all the time to allow inter-carrier roaming as it happens on mobile networks,” Transat's Baker said. “Carriers can provide their users with WLAN-enabled 3G services. WLAN operators can be exposed to millions of GSM users.”

Anjan Ghosal, president and CEO of Intellinet, said, “We were watching the 802.11 growth story and started to look at integrating applications using SS7. AT&T Wireless told us they would be spending money this year to come up with a convergence play.” (To date, the carrier has not said anything publicly about evolving its current Wi-Fi effort into an integrated service.)

Besides these vendor efforts and others, a new industry group called the WLAN Smart Card Consortium was recently formed to examine how efforts involving SS7 mediation and SIM cards could be standardized.

But while administrative-level integration is happening to some degree, top-tier carriers may not be so aggressive about pursuing it yet. “We have the capabilities that could be assembled for carriers to bill for both services, if they wanted to do that. We haven't seen first-tier carriers that are ready to do that,” said Wayne Purboo, vice president of research and development at Amdocs, which supplies billing systems to large telcos and mobile carriers.

John Ferrari, director of sales and marketing at Nokia, added, “Allowing authentication of users is the first step in allowing them to use different network footprints. [Network] roaming is the next step up the ladder.”

Without discounting the excitement over the convergence of mobile and Wi-Fi or the technological advancements that have been made to that end, a great deal of work remains before true network integration is a possibility — roaming in terms of dynamically choosing networks and registering on them isn't the same thing as roaming seamlessly between them while engaged in a single voice or data call.

Beyond the flexibility in customer choice that increasingly will be offered by front-end interfaces, the details of roaming between mobile and Wi-Fi networks begin to get a bit trickier. First of all, it's assumed by many industry experts that any roaming between the two network types in the foreseeable future would be limited to voice roaming. There doesn't seem to be much viability to data roaming because of the sharp dips in bandwidth that would occur as users cross from Wi-Fi hot spot coverage into mobile network coverage.

“Is a handoff for data of any value? I don't think you'll see a lot of people doing it,” Intellinet's Ghosal said.

Still, some acknowledge that data roaming could eventually have potential if connection reliability and security could be guaranteed. “Enabling mobile laptop users to browse the Internet while roaming between two network types with no interruption in the session will be a key feature for mobile workers,” the UMTS Forum's Fernandes said.

Even if data roaming is somewhat far-fetched, voice roaming — dependent on the evolution of technologies that would allow voice service to be provided through 802.11 network equipment — seems to be much more realistic.

One of the more notable steps toward integration in recent months was a three-way partnership announced by Motorola, Proxim and Avaya to explore how voice-over-IP technology and protocols might be merged with 802.11 network gear and dual-mode devices to facilitate voice-enabled Wi-Fi hot spots.

Dilithium CEO Paul Zuber said his company is contributing its unicoding solution to Motorola's end of this effort. Developing dual-mode base stations or integrating 802.11 radios and chipsets into existing base stations could be another method for tying together mobile voice and data coverage with the small-sphere, high-bandwidth coverage of Wi-Fi.

“Depending on the product involved, our technology gateway could be used for a hot spot link to a mobile network. It could be used in a base station,” Zuber said.

“It shouldn't be that difficult integrating the technology in a base station,” Nortel's Morell added. “You should be able to do it with off-the-shelf technology.”

“The Wi-Fi phenomenon is a perfect complement for GPRS and, eventually, W-CDMA,” acknowledged John Ferrari, director of sales and marketing at Nokia. “A dual-mode device should have the intelligence to sniff out the best signal to use.”

Ferrari noted, however, that while there are several ongoing projects in the industry designed to improve 802.11's reach, as well as allow mobile data access as a user moves at very high speeds (in a car or train going more than 60 miles per hour, for example), these more “nomadic” pursuits may not require the same ubiquity as mobile network base stations. “We have no plans to do it right now,” he said.

WORLDWIDE PUBLIC WLAN MARKET SIZE
	2002	2003	2004	2005
WLAN business users (in millions)	0.7	4.8	11.9	20.5
WLAN users that are also 3G subscribers (in millions)	-	0.3	1.7	5.3
WLAN users that are not 3G subscribers (in millions)	0.6	4.6	10.2	15.2
Total WLAN market (in billions of dollars)	$0.15	0.9	1.9	2.8
Worldwide 3G mobile intranet/extranet revenue (in billions of dollars)	$0.2	1.9	5.8	9.8
Total market opportunity (in billions of dollars)	$0.3	2.8	7.8	12.6
Source: UMTS Forum, Telecompetition

However, there could be alternatives to creating dual-mode base stations or retrofitting traditional ones with the 802.11 protocol. Wireless softswitches, which so far have seen limited deployment in gateway-to-mobile switching center applications, are believed to be on the cusp of much broader deployment in mobile networks to act as programmable servers hosting new services. One of those services could potentially be Wi-Fi, or a combination of applications allowing mobile voice service and Wi-Fi data at the same hot spot.

One executive in the fast-emerging wireless softswitch market said the technology to do that exists today. “If you are in a Wi-Fi network and you have some kind of IP data terminal that does both data and voice, there is no change to our architecture needed — we are just another server involved,” said Shamim Naqvi, founder and chief architect at softswitch developer Winphoria Networks.

Naqvi also said his company has applied for patents on technology “that allows the handoff between mobile and Wi-Fi networks to happen.” The handoffs would require a certain amount of change to Winphoria's architecture, but “it's something we can already do,” he said.

Naqvi added, however, that there are still hurdles to overcome before seamless voice roaming between the different networks becomes a reality. “We made a bet a few years ago when we saw Wi-Fi coming down the pike to develop that kind of capability, but it does require new handsets to be built that are interoperable, that support both CDMA and Wi-Fi, for example,” he said. “If they were available, we'd probably be doing it now.”

Newly developed Wi-Fi switches and managed hubs from companies such as Vivato and Aruba Networks also could play a role in network integration because they have ports that could interconnect with T-1s and Ethernet switches. Vivato officials said that while their Wi-Fi switch could let carriers operate and manage wireless enterprise hot spots, they haven't yet seen demand for interconnecting networks.

It seems that for now, there are many different companies and technologies at many different levels of the mobile/Wi-Fi convergence equation, all looking for signs that convergence strategies are ready to kick in. These signs, of course, need to come from customers. In that regard, it may fall to the device manufacturers to continue taking the market's temperature, and let the industry know when it's warm enough to meld their concepts.

“The handset makers need to have shipping orders in the millions before they will do this,” Naqvi said. “No one in this industry can speculate and manufacture without the pent-up demand apparent.”

Still, there is a definite sense that Winphoria and other companies are working on a new network model that eventually will come to fruition. “All the pieces of the ecosystem are falling into place,” Nokia's Ferrari said. “It has legs. The industry is just working out the dirty plumbing issues.”