WITH WIRELESS TECHNOLOGY SUPPLY GENERALLY outstripping demand the burning question is how one makes money, sometimes phrased as “What's the killer app?” With the usual caveat that it is very difficult to predict, especially about the future, the following are thoughts about those areas, sectors, and applications where wireless will almost inevitably become the primary communication medium.

Home Networking and Entertainment
“Digital Homes”—fully networked homes with digital entertainment centers—are increasingly moving into the mainstream. There are several drivers that have made this progression inevitable, from high-speed internet access to networked, digital entertainment devices. Under this broad umbrella lie a number of applications that are still evolving.

One of the primary drivers of this phenomenon is the increasing availability of broadband access to residences. Over half the households in the U.S. are now online, and about one in seven has broadband access. The example of South Korea is perhaps most striking—over two thirds of the households have broadband access. This has triggered a whole host of applications (including the availability of television shows for downloading) and has significantly changed user behavior—the average user in S. Korea spends more than twice as long online (about 20 hours a week) as his counterpart in the U.S.

The factors that lead to a high rate of adoption of broadband access are fairly clear—pricing, public policy, competition, and the default expectation (i.e., everyone has it). Once a household has broadband access, the desire to share the connection among multiple PCs and household members is immediate. The most straightforward way to do so is using a wireless LAN.

Another driver, which has already been alluded to above, is the increasing prevalence of multiple PCs in homes. But this is rapidly being dwarfed by the presence of an even larger number of digital, networked entertainment devices. Audio has become almost completely digital for over a decade, still cameras, camcorders, and satellite TV are rapidly following suit, and cable and broadcast TV are inevitably transitioning as well.

The storage and swapping of media files, first triggered on a large scale by Napster, is now crossing over to the video domain thanks to TiVo and its ilk, and to the lack of effective Digital Rights Management. This trend will be accelerated by the networking capability of storage and media devices. Soon, with the introduction of more intelligent set-top boxes and home gateways, the distinction between entertainment and computing equipment, and their respective storage devices, will blur. Microsoft's Xbox initiative, the XP Media Center, Sony's PlayStation strategy, Intel's Extended Wireless PC Initiative, are all about this goal.

All this points in one direction - digital, networked homes, and the use of wireless to do away with cabling and provide connectivity all around the home.

Home and Industrial Sensors and Data Collection Devices
A less glamorous, but potentially more lucrative, application in homes is that of providing ubiquitous sensing and data collection all around the house. This ranges from security applications (cameras and listening devices placed around the lot backhauling to collection points), safety (sensing various environmental conditions and reporting back), and utilities (reading power and water meters and wireless transmission of the data thereby obviating the need for manual data collection).

The need and utility of these applications seem to make their eventual adoption virtually inevitable. There are a few hurdles to be crossed. The first is that of standards and interoperability—this still needs to be done and is a necessary condition for large-scale deployments of sensor networks. The second is that of power—sensing and communication devices today have battery lives of several years.

This will continue to increase, but one of the most interesting innovations is the concept of Energy Scavenging—i.e., the extraction of energy from ambient sources such as mechanical vibrations or temperature gradients, for powering the systems.

Finally, there are privacy issues—widespread sensing and data collection devices are already raising questions about privacy, and these need to be effectively addressed within a framework that ensures that this not be a legal quagmire.

Enterprise and Vertical Applications
Wireless penetration in verticals and industrial applications has been successful because it serves a need that cannot be met by wired networks. Data collection, inventory tracking, enabling mobile professionals (those who are not desk-bound, for example medical staff at hospitals) to be constantly connected are applications where there is a clear need for wireless to solve the problem.

By contrast, wireless penetration in other enterprises has not yet taken off to quite the same extent primarily because it is convenient, but not yet absolutely necessary. It is rare for a wireless LAN infrastructure to replace the wired infrastructure; in environments where every office and cubicle is wired, solving the “last foot” problem is not usually critical.

One application that has gotten a fair amount of attention is that of wireless telephony in the workplace. The use of wireless LANs inside buildings to complement cellular telephony has spawned a number of efforts. This is reminiscent of the DECT/GSM effort in the mid 1990's in Europe, and commercial offerings included BT & CellNet's OnePhone service that was launched in 1999. However none of these initiatives took off, for a number of reasons including carrier motivation, business model, pricing, regulations regarding inter-working between landline and wireless carriers, etc. Wireless LAN (i.e., 802.11) chipsets are not well suited to carry voice, nor are they efficient with respect to power that could be a crucial drawback. The advantage from the carrier's perspective is also not clear (it does reduce the load on the network, but it also reduces minutes of use and consequently the revenue). It remains to be seen how the cellular/802.11 initiatives will pan out.

Personal Connectivity
Multifunctional cell phones and inexpensive wireless data plans are combining to offer a tempting invitation. On the device side, cellular phones are starting to act like PCs (with e-mail, browser, and a full suite of office applications) sometimes combined with cameras and other media devices. On the connectivity side, the cost (e.g., $10 for all-you-can-eat at better than dial-up data rates) makes it almost painless to always be connected. How can one refuse?

The combination devices and always-on connection will spawn a number of applications and services, including location-based services, multi-player video games, etc.

Finally, the killer business—wireless-free rehab centers where connectivity addicts can go to be isolated, recuperate, and deal with withdrawal. Getting away from it all will become so difficult that there will be a large clientele willing to pay generously for the luxury. Remember, you first heard it here.

Rajeev Krishnamoorthy is entrepreneur-in-residence at Globespan Capital Partners, in Palo Alto, CA. He has pioneered several novel communication systems, from 802.11b wireless LANs to the first commercially available multiple-antenna (MIMO) system. Most recently Rajeev was VP, Technology at Iospan Wireless (acquired by Intel). Prior to Iospan, Rajeev was at Bell Labs where he co-invented and developed the high speed wireless LAN (proposed by Lucent to the 802.11 standards committee resulting in the 802.11b standard).Rajeev received his BS from Caltech and his PhD from Cornell University. He can be reached at rajeev@alumni.caltech.edu