Ultimate mobility

Wi-Fi is the rage today, but the real mobile story lies in the convergence of multiple network types, application persistence and multi-modal devices.

You wake up and, after sufficient amounts of caffeine, turn on your mobile network device of choice. Five e-mails grace your in-box, three of them urgent. A quick glance at your workgroup buddy list reveals your boss is already in the office, but the icon next to her name indicates she doesn't want calls. Your calendaring application shows a customer meeting at 9 a.m., so you tap the "Today" icon and an alert goes out to your staff and colleagues that you'll be out of the office till late morning.

Later, arriving for your appointment, you finish a voice mail to a friend about basketball tickets. Your mobile device, detecting your rights on the customer's Wi-Fi network, seamlessly moves the call from the your cellular network to the wireless LAN. You don't get dinged for the roaming, thanks to the chip-level authentication your mobile device uses and the corporate roaming agreement. When your meeting starts, your mobile device knows not to ring audibly, although color-coded instant messages might pop up.

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From MAN and LAN to WLAN Mobilize those apps Recipe for clunky devices? The converged mobile future What to ask wireless vendors

You wake up and, after sufficient amounts of caffeine, turn on your mobile network device of choice. Five e-mails grace your in-box, three of them urgent. A quick glance at your workgroup buddy list reveals your boss is already in the office, but the icon next to her name indicates she doesn't want calls. Your calendaring application shows a customer meeting at 9 a.m., so you tap the "Today" icon and an alert goes out to your staff and colleagues that you'll be out of the office till late morning.

Later, arriving for your appointment, you finish a voice mail to a friend about basketball tickets. Your mobile device, detecting your rights on the customer's Wi-Fi network, seamlessly moves the call from the your cellular network to the wireless LAN. You don't get dinged for the roaming, thanks to the chip-level authentication your mobile device uses and the corporate roaming agreement. When your meeting starts, your mobile device knows not to ring audibly, although color-coded instant messages might pop up.

Cool, yes. Feasible, no. You've got all the pieces at your disposal and can use some in combination today, but the applications, the devices and the network infrastructure are not yet agile enough to support such a connected user. Such convergence is at least three years away, analysts and users estimate.

As George Surdu, director of IT infrastructure for Ford Motor in Detroit, says: "We've got it all - Wi-Fi, bar-code scanners, cell phones, PDAs - but it's tough plugging it all together."

From MAN and LAN to WLAN

Disparate wireless networks likely will come together before convergence at the application and device levels.

In today's wireless WAN world, AT&T Wireless and Cingular could support roaming between their networks, which rely on Time Division Multiple Access (TDMA) technology. But they couldn't offer roaming between their networks and the Code Division Multiple Access (CDMA)-based network of either Sprint PCS or Verizon Wireless. The TDMA and CDMA systems send and receive information differently. But as silicon changes and multi-mode phones become available - already happening in Europe and expected stateside next year - users will be able to roam between TDMA and CDMA networks worldwide. Carrier adoption of the International Telecommunication Union 3G digital cellular technology also will facilitate such roaming. Besides being able to handle TDMA and CDMA interfaces, 3G networks can carry data at speeds ranging from 128K to 2M bit/sec. U.S. carriers are expected to begin 3G rollouts next year.

Cellular providers, ever keen to exploit a revenue opportunity in an otherwise flat commodity market, also now are focusing outside their traditional WAN purview. Most are trying to figure out how to get into the Wi-Fi hot-spot business so their users will be able to tap the cellular network for voice calls and high-speed hot-spot access to corporate resources or the Internet. IEEE 802.11-based hot spots offer access at rates of 11M or 54M bit/sec, depending on what version of the wireless Ethernet standard is supported.