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This 45-Mile ‘Wi-Fi’ Could Connect a Smarter Power Grid

A startup’s wireless technology sends low-bandwidth signals over long distances, even underground.
June 27, 2011

If your home Wi-Fi router wasn’t cooped up indoors, it could send a signal about a 20th of a mile before the signal became too weak and distorted for a computer to receive it. Technology developed by San Diego startup On-Ramp Wireless uses the same frequency, but less power, to send data signals 45 miles, thanks to algorithms that make the signals very resistant to noise.
The technology, called Ultra-Link Processing, transfers data at a very low rate compared with a home broadband connection. But On-Ramp intends to offer it as a way to enable “smart energy” grids, in which simple sensors installed in home energy meters, for example, report local activity back to utilities, allowing them to manage power generation and distribution more intelligently.

Smart-grid infrastructure is needed to cope with the fluctuating output of renewable energy sources at large scale, and it could make feasible micro-generation, whereby consumers make their own power and sell any surplus back to the grid. Today’s smart-grid sensors typically use Wi-Fi-like technology with Wi-Fi-like ranges, or unlicensed radio bands that can reach a couple of miles. Cellular networks can also be used, but these connections are under growing pressure from data-hungry phones and tablets.

“There’s no technology available for devices that just need a trickle of connectivity over long distance,” says On-Ramp’s chief technology officer, Ted Myers, who says that with a clear line of sight, On-Ramp’s technology can send a signal 45 miles. He is targeting devices that use less than 50 bits per second, roughly 100,000 times less than the average U.S. broadband speed of five megabits per second.

A trial network in San Diego requires just 35 strategically located access points to collect data from smart meters and other devices equipped with On-Ramp’s technology across a 4,000-square-mile area. “It boils down to a cost advantage,” says Myers. “You need fewer access points this way.” California utility PG&E is currently rolling out smart meters based on more established technology which will require over 1,000 access points to cover the same area, Myers claims.

Long-distance link: This device can send a signal at the same frequency as Wi-Fi 45 miles, while using much less power.

With the aid of a $2.1 million grant from the Department of Energy, On-Ramp is now working with utility San Diego Gas and Electric to monitor hard-to-reach pieces of energy infrastructure. In other trials, On-Ramp is working with oil company Shell to link up pressure sensors on gas pipelines in Europe, and with defense contractors interested in tracking objects equipped with Ultra-Link Processing transmitters.

At the heart of the technology is a suite of proprietary algorithms for transmitting and decoding data signals. These enable On-Ramp’s receivers to pluck a signal that has been weakened by distance out of the noise generated by other Wi-Fi and radio signals in the same frequency bands. The technology can even pick up signals that are weaker than the surrounding background noise, says Myers—something that devices using cellular or mesh networks cannot do. According to standard models for predicting wireless performance in real-world scenarios, On-Ramp’s technology is able to use signals roughly 100 times (20dB) weaker than those needed for a cellular link, and 3000 times (35 dB) weaker than those needed for grid sensors that link together into a mesh network, he says. It can even send signals from sensors underground, for example on subterranean electric or gas lines.

Chips that have On-Ramp’s proprietary technology built in are required, though. Devices used in trial deployments so far have been based on a first-generation chip produced in Taiwan. A version due this fall, the MicroNode pictured, is roughly a third cheaper, and it will make smart meters equipped with On-Ramp’s technology competitive with those already being rolled out by some utilities, says Myers.

Rajit Gadh, who researches smart-grid technology and deployments at the University of California, Los Angeles, says that utilities are certainly interested in reducing the cost of smart-grid infrastructure, and adds that new types of wireless networks could help. “There’s not an exact match between the technology that’s out there and what the smart grid needs to really deliver,” says Gadh. “There will be wireless links operating at a range of different frequencies used in different scenarios, for example urban or rural areas, or developing-world cities that are denser.”

Most technology in use today, Gadh says, was developed for other purposes. For example, many smart-grid deployments use the Zigbee protocol that was originally intended for linking up appliances in networked homes. However, On-Ramp is competing with many other companies bidding to connect the parts of the smart grid, Gadh points out, and most of these use more established technologies that utilities are much more familiar with.

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