Intel Goes The Distance on Wi-Fi: 60 Miles
March 20, 2008
Using 802.11x networking and some "secret sauce," it can stretch wireless connectivity -- helping remote communities get online.
Getting a clear wireless signal in a coffee shop or airport can be a pain even when sitting mere feet from the access point. Now imagine shooting an 802.11 signal 100 kilometers (62 miles).
Intel's Rural Connective Platform (RCP) is promising to do just that.
All that's needed is unobstructed line of sight. Jeff Galinovsky, a senior platform manager at Intel, said the RCP's transmitters theoretically go a maximum of 100 kilometers. But at that distance, the curve of the Earth itself becomes a line-of-sight obstruction.
"What [RCP] really allows us to do is get a solid connection at 30 to 60 kilometers, which is a much more realistic distance to get a good, solid connection," Galinovsky told InternetNews.com
With the RCP, which Intel aims to begin selling later this year, the company aimed to develop technology to beam Internet connections out to rural areas too far from any local connections -- and where laying copper wire is either too expensive or subject to theft.
That strategy, designed for sparsely populated areas, stands in sharp contrast to WiMAX, which counts on economies of scale to pay for itself.
Also unlike WiMAX, and conventional 802.11x Wi-Fi, RCP is based on two points: a sender and receiver. Whereas a typical 802.11x access point sends out its signal in all directions and takes connections from all devices in range, the two RCP transmitters have a matched connection, linking only to each other.
In a typical usage scenario, a receiver tower would then run a wire down to a network, switch or server -- which in turn would distribute Internet connectivity throughout the immediate area.
While line of sight remains a challenge, RCP also supports workarounds. If trees or other objects interfere with two towers' communication, relay towers can be set up to transmit the signal along multiple points, avoiding obstructions.
Intel uses a modified version of the 802.11a/b/g protocols along with packet division multiple access (PDMA) technology to boost the signal much farther than the 400-foot maximum of your typical wireless router.
Combining 802.11 technology with PDMA yields the "secret sauce" that makes two RCP towers' signal travel so far, Galinovsky said.
"That's coupled with the technologies we invented for PDMA to do slotted communication, where we give each other a turn to talk because we know we're the only two on the network," he said. "So we can get longer distances and still keep the high bandwidth."
The technology does not yet support 802.11n, since the industry specification has not been completed. However, Intel said it plans to add support for the higher-bandwidth protocol once it's finalized.
RCP also includes an auto-repair technology, so if a tower fails, a technician won't have to be dispatched to a potentially remote area. Each RCP device figures out its role automatically -- whether it's a source, destination or repeater tower -- and self-configures when necessary, Galinovsky said.
The technology's speeds also have proven nothing to scoff at. Intel, which has test deployments in India, Panama, South Africa and Vietnam, said its Indian site has achieved 6 to 8 megabits of throughput over a 33-kilometer link.
The best part, however, may be the price: $1,000 per pair.
"That's a big deal where you don't have a lot of people to support the cost of deployment for a WiMAX tower," Galinovsky said.
Michael King, research director with Gartner, said that while rural communities' priorities should be on clean water and healthcare, the RCP program could be great for those who advocate closing the "digital divide."
"It does provide a solution to a problem that a lot of folks believe is quite real, and that is an inability to connect relatively rural users," he told InternetNews.com. "It's inexpensive, uses a standards-based kit, and it's going to be relatively cheap on the client side."
However, King added that he felt the distances Intel is talking about are a tad ambitious, and that eventually, towers will be deployed more closely to each other to preserve signal strength and integrity.
"Right now, we're at the stage of showing what it can do, which is a pretty common occurrence with wireless technologies," he said. "You start showing what it can do, then start to ratchet it down because you don't want to be on the ragged edge of that stuff."