For wireless sensor nets, reality sets in

CHICAGO - The starry-eyed gave way to the hard-nosed at a conference last week for sellers and buyers of wireless sensor networks.

Attendees directed tougher and more pointed questions at suppliers than at the debut Wireless Sensing Solutions Conference a year ago. Faced with extravagant promises about the benefits of temperature, vibration and other sensors married to low-power wireless mesh networks, attendees wanted to know about security, management, interference, reliability and total cost of ownership.

"We've been through the hype and buzz phase," said Jeff Bussgang, general partner with IDG Ventures, a venture capital firm in which Network World's parent company is a limited partner. "Then new technologies go through the reality phase. People are discovering these technologies are more complicated than anticipated."

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CHICAGO - The starry-eyed gave way to the hard-nosed at a conference last week for sellers and buyers of wireless sensor networks.

Attendees directed tougher and more pointed questions at suppliers than at the debut Wireless Sensing Solutions Conference a year ago. Faced with extravagant promises about the benefits of temperature, vibration and other sensors married to low-power wireless mesh networks, attendees wanted to know about security, management, interference, reliability and total cost of ownership.

"We've been through the hype and buzz phase," said Jeff Bussgang, general partner with IDG Ventures, a venture capital firm in which Network World's parent company is a limited partner. "Then new technologies go through the reality phase. People are discovering these technologies are more complicated than anticipated."

Three engineers with Caterpillar's Systems and Controls Research group evaluated wireless mesh sensing at the show, which attracted about 400 attendees and about two dozen exhibitors, both increases from a year ago. Caterpillar would seem to be a perfect candidate for such technology, from asset management of heavy equipment in dealers' yards to monitoring earth-moving and mining machines.

But what the engineers found at the conference sparked questions and concerns, ranging from the viability of IEEE 802.14.5-based radios on big machines to possible interference when different wireless technologies are active in the same area.

"There's not real collaboration between the various [wireless] standards bodies," said Tien Doan, one of the trio. "So you may have radio interference, and that could affect the reliability of the network."

Attendees were unimpressed, and impatient, with grandiose application possibilities.

Srini Krishnamurthy, vice president of business development for Airbee Wireless, outlined a wireless sensor mesh project under study for Ronald Reagan Airport in Washington, D.C. Every door in the airport could be outfitted with 900-MHz wireless sensors and automated locks, networked to a central point where rules could be set for when a door could be opened, by whom, by time of day, without the need for guards.

This idea sparked a pragmatic response from Samuel Reed, an electrical engineer with Key Technologies of Baltimore: "Can a terrorist walk into the airport with a 900-MHz jammer and shut the whole place down?"

Another attendee wanted to know how many products had shipped with ZigBee Alliance's mesh networking software stack.

The ZigBee Alliance , a group of start-ups, integrators and other manufacturers, has crafted higher-level specifications for security and networking, as well as a set of application-level profiles for use by programmers.

"There are some prototype projects with 100 to 150 nodes," said William Craig, program manager for wireless communications at ZMD America. "But you can't point to a [ZigBee] thermostat today." He said ZigBee-based products will start to hit the market late this year.

Another questioner wanted to know whether large-scale wireless mesh networks could overwhelm the available radio frequency spectrum. None of the speakers answered with an unqualified "no." They did point out that the ZigBee specification and the underlying IEEE 802.15.4 radio standard had various features to avoid collisions and find open channels; and that sensors could be set to transmit only occasionally and send small amounts of data when they did.