Intel is developing a way to locate a Wi-Fi user by timing how long it takes for packets to travel to and from a wireless access point. This could prevent unauthorised users outside a house or office from accessing a network indoors.

Precision location technology is one of several key ideas for the next few years that Justin Rattner, Intel senior fellow and director of the company's Corporate Technology Group, showed off during a keynote presentation on the last day of the IDF (Intel Developer Forum) in San Francisco yesterday.

The access point times how long it takes a packet to travel out to the client system and come back. From the length of that round-trip time, it can extrapolate how far away the client is, Rattner said.

The technology is so precise, even up to 70m from the access point, it can tell whether a client device is inside or outside a wall, Rattner said. For keeping neighbours or passers-by from intruding on a home or enterprise network, it might even be more effective than current encryption systems, he added.

Another possible use of the location technology demonstrated at the show was to make a video program follow a user from room to room. For example, if a user carried a notebook PC, the program could move from a TV in the living room to a large PC monitor in an office and then come up on the notebook when the user got out of range of either stationary display, he said.

Both access points and clients would have to be modified to support the system. Intel plans to bring the technology to the IEEE 802.11 group for standardisation, he said. Theoretically, the technology could be extended to other types of wireless networks, he said during a question-and-answer session after the presentation.

The coming advances Rattner demonstrated are intended to help systems take care of themselves. PCs, servers and other devices require too much hands-on tinkering, he said.

"We really need to get to a point where the systems support the users, rather than users supporting the systems," according to Rattner.