Of course, there are many hurdles to a data-only infrastructure. The industrial/scientific/medical spectrum could rapidly become overcrowded, forcing carriers to license pricey spectrum after all. Interference could degrade the quality of those multimedia Web streams. There is no agreed-upon transmission protocol, leaving data-only services open to the incompatibility that besets 3G. To avoid walking around with several different gadgets, we’d need that software-radio device to switch handily between voice and data modes. Stray beyond urban areas, furthermore, and it’s hard to imagine a nanocell on every fifth fence post.
Which brings us back to the contrarian vision of a hybrid network: a 2.5G cell-phone system providing clear voice, paging and always-on Internet access to our handheld devices outdoors; and the cable-TV and computer-network wiring already in place indoors providing the full-blast broadband experience-which the handheld can tap into.
This architecture could be built relatively quickly and inexpensively. High-speed, broadband Internet will soon be available in many indoor environments, as companies such as Cisco Systems and Juniper Networks busily string fiber-optic cable to homes and businesses. A simple wireless transceiver in the corner of a lobby or living room would feed your mobile device; you could access the high-speed networks being built into modern trains and planes the same way. This scheme also dovetails nicely with what is happening inside numerous businesses, where aging, hard-wired local-area networks are being replaced with “fixed” indoor wireless networks, which are cheaper and easier to install and readily support broadband data rates. It would be simple for your mobile device to latch on to this infrastructure.
Looking toward the end of the decade, you may end up using 2.5G wireless for convenient cell-phone calls and Web access while traipsing around town, then cut over to a fixed-wireless network when you step into the coffee shop, subway station or meeting room, perhaps using a software-radio Web phone that switches between voice and data as needed. Flip open your 2.5G CellMate while walking down Main Street to call home, then convert to data mode to download a shopping list after your spouse tells you about a sudden party you didn’t know you were hosting. When you step into Mammoth Grocery, CellMate switches over to the store’s fixed-wireless network so you can quickly check Online Wine to see which vintage will complement dinner. The store’s map appears, leading you to the wine aisle. You point CellMate at the checkout’s infrared scanner to debit your bank account. And that indoor/outdoor hybrid system, rather than the grand vision of “3G,” might be what the future really looks like for broadband wireless.