Roam If You Want
To"> "Adding value" means allowing the user to roam both voice and data connections from slower cellular to faster 802.11 networkswithout dropping calls, losing packets or sacrificing voice quality. It should be seamless. Heres where the carriers have to step up. Once the phone is able seamlessly to select the fastest (or cheapest) network that it sees, the voice and data providers need to support the switch from one to the other. Ideally the cellular network would see its VOIP-to-voice cloud bridge as just another cellular node that would let a call switch from GSM to 802.11b just as it would move from cell tower to cell tower.Another way would be to add a box to the operators premise location and treat your 802.11 access point as just another cellular base station. One of the big problems, though, is deciding when to hand off from 802.11 to cellular. We all know how tenuous wireless LANs can be. Should you automatically switch when you walk behind a wall, for example, and temporarily lose the LAN connection? Whats the threshold? One packet? Ten? One hundred? Another issue: When youre on a cellular call, what happens when you come within range of an 802.11 hub? Will the system try to connect automatically? What if its at Starbucks or McDonalds, and you dont have a subscription? Those issues need to be worked out as wellbut built-in GPS and some kind of location awareness will help. It would be great if your communicator knew when you were in the office or at home, and used that knowledge to attempt to force an 802.11 connection but while on the street, it eschewed just any old dirty-net it happened across. Finally, what about using both networks simultaneously? What if youre on a voice call on cellular, but your communicator detects an 802.11 signal? It would be great if it could start downloading e-mail and attachments in the background while you finish your cellular-based callor even multiplex the two networks together for more bandwidth. But thats even harder. The good news is that these problems are being addressed. According to Peebler, well see devices next year that will be able to use both Wi-Fi and cellular networks sequentially. Itll be another year before we see simultaneous network use and automatic roaming between the two. As for GPS, Bluetooth and other networks? Itll be 2006 at the earliest. Hmm. Perhaps we wont see the baby bells vaporize by 2007. But I still think their days are numbered. That number might just be a bit higher than I thought, but its still finite! Want more information on Intels communicator project? You can find it at Intels site. eWEEK.com Wireless Center Columnist Jim Louderback is editor in chief of Ziff Davis Internet.
According to Peebler, these problems are not intractable. Intel, along with a number of cellular and equipment providers, are working on the issues. One way around it: Have your corporate PBX handle the call switching, essentially allowing the PBX to connect to your cell phone, while keeping a persistent VOIP connection live to whomever youre calling.