Chapter 13: Wi-Fi and Cellular-A Dynamic Duo

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The buying public definitely is attracted by all things wireless. When it comes to wireless data access, most of the buzz is about Wi-Fi. If you listen closely, however, you can still hear a slight murmur of excitement about cellular's "Third Generation" (3G) networks, but these 3G networks are being held back by high start-up costs, still uncertain technology and a shortage of supportive devices. Is it any wonder that many cellular operators ponder the question: can Wi-Fi serve the same purpose for less money?

Can 3G and Wi-Fi Co-Exist in the Same Network?

Cellular technology revolutionized voice communications, and the industry has high hopes that-with the help of 3G technology-it will be the same with data communications. After all, cellular-enabled devices are in the hands of more than 1.3 billion subscribers, worldwide. Indeed for several years, industry experts considered cellular technology to be the most likely mode for wireless access to the Web. Cellular operators and equipment manufacturers invested billions of dollars on spectrum licenses and 3G related gear. Wi-Fi's emergence upset the established order of the wireless industry-forcing everyone involved to rethink their target markets, applications, partnerships, and strategies.

In an effort to protect their turf, some in the cellular industry are lobbying governments to limit WLANs' spectrum or even to make WLANs illegal. But others, such as the UMTS Forum (the industry group that represents 3G vendors and operators) take the position that wireless local area networks (WLANs) are "complementary," not competitors of cellular. UMTS's position is based on the fact that Wi-Fi has a short range but a powerful signal (i.e. fast) and cellular provides a long range but a comparatively weak signal (i.e. slow), and thus could be paired to create a dynamic duo.

To understand why each group feels as it does, let's consider the arguments put forth by each to support their position.

The proponents of a complementary relationship between Wi-Fi and cellular argue that:

• Wi-Fi is best at high-speed data transfer, with a potential for voice in the future after QoS concerns are addressed.

• 3G delivers superior voice and mobility and can fill-in wide-area gaps.

• There is a good business model for the cellular operator: hook users on wireless broadband with Wi-Fi then add 3G into the mix.

• Some in the manufacturing and vendor communities already integrate dual-mode (Wi-Fi/cellular) capabilities into their products, e.g. Qualcomm with its CDMA/802.11 chipset; Nokia and its GSM/GPRS/802.11 NIC Cards; Ericsson, which sells and deploys public Wi-Fi networks such as TeleDenmark in Europe).

Chris Land, director of strategy for Singtel Optus, a giant telco in the Asia Pacific region places Optus Mobile among the Wi-Fi detractors. He is adamant that Wi-Fi is no replacement for 3G. Instead, he says, "The difference between the two is the right to use a finite piece of spectrum for a period of time.... With 802.11, everyone can use the unlicensed spectrum. This will create problems in the long term, particularly as the space becomes congested."

The contingent that feels Wi-Fi will cripple 3G reasons as follows:

• Wi-Fi will render 3G technology redundant...any service 3G can provide, HotSpots can top it. Microsoft stated publicly that even with interference, Wi-Fi data transfer is still faster than any cellular technology, whether it's GSM/GPRS, EDGE, WCDMA or cdma2000. Thus HotSpots may cannibalize 3G operator's revenue. Even the UMTS Forum (which supports the dynamic duo scenario) suggests that 3G operators could potentially lose 12% to 64% of their Revenue to HotSpots by 2006.

• It costs a bundle to implement 3G. For instance, the provider must pay around hundred billion dollars for a 3G license versus Wi-Fi's free spectrum, not to mention the cost of building out a new 3G network. So why invite an upstart like Wi-Fi into their network mix?

The author takes the position that these two technologies could and should work as a team. Still, even among the supporters of such pairing, there isn't a consensus as to how such a partnership would work. Here's why:

First, the access points (the radio that creates the wireless field and manages network traffic) would need to be more complex than what's available today. In fact, these access points would be so complex that some of the heavy lifting would need to be done by a computer network.

Next, manufacturers of the popular diminutive cell phones will have to create a phone that uses a Wi-Fi network without draining its battery within a few minutes. (Motorola says it has solved this problem.)

There also is a dearth of hybrid gear, rendering most of today's network gear, access points, cell phones, laptops, and PDAs unable to make the transition between cellular and Wi-Fi. But this situation could be remedied quite soon-forthcoming plug-in cards for laptops will enable a user to access Wi-Fi, if it is available, and to fall back to a slower cellular connection, if it is not. Chip makers are in the midst of designing multi-mode chips to support both technologies; other vendors and manufacturers have their R&D departments working overtime to develop their own hybrids.

The normal business considerations, such as how HotSpot operators and cellular carriers would cooperate and how they would split revenue, would need to be untangled. This will be tough. The devil is in the details. For instance, items remaining to be worked out include how to provide a multilateral roaming platform, a common authentication and accounting system, and a shared billing standard. Bridgewater Systems, Intel, and others, however, are already addressing those issues.

Other questions to answer include:

• How does a network determine what pathway to assign a given user when that user signs onto the network-Wi-Fi or cellular?

• How do you make the transitions between the different networks seamless so that when a user switches from, say, an Instant Messaging (IM) or Short Text Messaging-better known as SMS (Short Message Service)-(which can be handled easily by cellular) to sending an email message or downloading a video clip (both would be better handled by a Wi-Fi connection), the user never knows he or she has left one connection method for another?

The answer may be in products by Ericsson, Lucent, Flarion Technologies and others that provide seamless handoffs between Wi-Fi and cellular networks.

Many in the industry are hard at work making the dynamic duo possible. For instance, Avaya, Proxim Corporation, and Motorola Inc. announced in early 2003 that they are collaborating on the creation and deployment of converged cellular, Wi-Fi, and Internet Protocol (IP) Telephony solutions. The solutions are enabled by an array of new products including a Wi-Fi/cellular dual-system phone from Motorola, Session Initiation Protocol (SIP)-enabled IP Telephony software from Avaya, and a voice-enabled WLAN infrastructure from Proxim. The jointly-developed, standards-based solutions support contiguous voice and data service to users across enterprise networks, public cellular networks, and HotSpots.

This chapter will discuss how the communications industry is tackling such issues. But first, the reader must understand how cellular technology works so the reader can more fully envision the many ways Wi-Fi can supplement and, in some instances, even replace cellular.

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