Advanced modulation and RF transmission schemes are quickly moving from lab to field to solve real-world problems, speakers told last week's IEEE Radio and Wireless Symposium.
In discussions ranging from ultrawideband (UWB) personal-area networks to Wi-Fi meshes, academic researchers presented concrete examples of advanced wireless data and sensor networks addressing people's needs around the globe.
While the Consumer Electronics Show in Las Vegas formed a concurrent backdrop to the Radio and Wireless Symposium in Long Beach, Calif., the researchers had more on their minds than consumer markets.
Take Deborah Estrin, for example, of the University of California, Los Angeles. The principal researcher at the school's Center for Embedded Networked Sensing, she demonstrated river and forest monitoring, showing how wireless sensor nets combine with actuators and robotics to form adaptive eyes for such tasks as precision agriculture and tracking species diversity.
"The heterogeneity and spatial variability common to many environmental problems are almost tailor-made for embedded wireless sensor networks," Estrin said in a popular invited talk. "If you don't have that fine-grained variability, you don't really need to sense at multiple points."
The UCLA center grew out of a project to develop prototypical wireless sensor networks for the Defense Department. That work was directed by professor William Kaiser, who more recently has been developing a Low Power Energy Aware Processing (Leap) network model in which microcontrollers are recruited as duty processors to keep networks operating for as long as 20 years at 20 to 60 percent duty cycles.
Estrin, the sister of communications entrepreneur Judy Estrin, said that while many sensor nets use solar power, Leap uniquely has the network itself "harvest" solar power to use it more efficiently.
In recent months, Estrin said, the center's networks have:
• Measured arsenic contaminant transport in drinking wells in Bangladesh;
• Conducted seismic monitoring in the aftermath of an October 2005 earthquake in Pakistan;
• Studied the mixing of the San Joaquin and Merced rivers in California; and
• Observed the microclimates of several continents using terrestrial-imaging nets.
Small robotic and actuator subsystems are critical in some of these applications, Estrin said, because node mobility can help overcome the inherent undersampling of static nodes on a network. Typically, the center's networks employ three tiers: simple, dumb "motes" at the endpoints; microservers to control many motes; and autonomous mobile nodes, many of which use cameras and other sensing devices in much the same way interplanetary missions rely on robotics.
Estrin said this tiered model allowed sufficient local, decentralized participation from citizen-researchers, particularly in tracking natural disasters like earthquakes and floods. But, she said, those in control of such bottom-up networks must realize that privacy concerns demand that local participants can selectively decide whether to share only some of the information they collect.