Solving the Multi-Network Wireless Problem

Getting 802.11b and cellular networks to play nice together is not a trivial problem, discovers Wireless Center Editor Jim Louderback. Intel's System Technology Lab is working the problem, though, as part of its Universal Communicator project.

Last week, I wrote about how VOIP, cellular and WiFi will combine to make traditional phones and POTS obsolete. But based on a discussion I had with a development manager at Intels Systems Technology Lab, there are still some thorny problems that need to be resolved.

First some background. Intel has put together an internal group of scientists and researchers to help realize its vision of seamless access to information from any device, using any available network. One project theyve been working on is a "universal communicator," designed to communicate on 802.11 and GSMs data network, along with network 3D gaming, video and audio playback, and other media capabilities.

It turns out that the device itself isnt hard to build. Although Intels grand plans for a single tunable radio, built onto a CPU, is still mostly fantasy, putting multiple radios into a single device isnt hard. Instead, network and radio co-ordination present the biggest challenge. "Its a huge task," explains Intels Bryan Peebler. "Ultimately, you want to get a single reconfigurable radio," he adds, "but thats still years away."

Intels prototype universal communicator includes a GSM GPRS radio, and an 802.11b radio. Intels recent purchase of Mobilian seems to suggest that Bluetooth should be incorporated pretty quickly as well. Once you put multiple radios in a device, you then have to ensure that they dont step all over each other as they communicate.


There are two different types of interference. The first, frequency interference, occurs when two radios transmit on the same frequency. Bluetooth and 802.11b, for example, both work at 2.4 GHz and can be a problem. The solution, according to Peebler, is to "time-slice between 802 and Bluetooth so they dont step on each other."

The other big problem: analog interference. Thats what you get when a poorly shielded component generates so much noise that a radio transmitter/receiver cant do its own job. "In our device, weve done some interesting stuff on radio placement and shielding" to cut down on analog interference.

Once youve solved the physical-interference problems, you run into network coordination issues, which are much harder to resolve. "Our premise is that it is reasonably simple to put two radios in a device. Its more difficult to make them work together to add value to the user."

Next page: How users can navigate voice and data connections.