Wireless Sensor Networks on the Verge

I recently had the opportunity of visiting David Nagel at George Washington University – a leading researcher in the field of wireless sensor networks. For those not familiar with Wireless Sensor Networks, Dr. Nagel defined it as follows: “Wireless Sensor Systems use pre-determined, single-hop radio frequency links to transfer information from the originating sensor node through other nodes, routers, and gateways to users. Networks with many sensors and communication nodes provide situation-determined multi-hop paths for the information to flow from the source to the destination. These networks can be ad hoc, that is self-organizing which simplifies both their deployment and employment. Also, their configuration in two-dimensional arrays called meshes enables information to travel over alternative available paths which greatly increases the reliability of information delivery. “

Simple networks of 20-50 nodes in a handful of specific applications such as building automation, home networking, and even parking meter monitoring are being used today. Applications with few variables (those parking meters aren’t going to move and if the node stops working the risk is low) are being installed today by industry while university and government groups are researching how to solve the more difficult ones such as how to make each node work autonomously but cooperatively. In other words the node must be able to control its own functioning (e.g. waking up to make a measurement) as well as work in a cohesive manner with other nodes (e.g. sending or receiving data or commands to other nodes in the network). Also, dealing with 20 nodes is not so difficult but how do you handle 2000 nodes or 20,000 nodes. At some point the old way of programming must give way to new techniques to support such large numbers.

Some of the more challenging applications include swarming networks. Researchers envision autonomous vehicles operating under computer control with little or no human control. This will require processing large amounts of data and extensive communications among the vehicles. The work is driven by the government seeking to build autonomous vehicles for work in dangerous situations such as combat zones.

The second application involves the use of sensors for biological detection. In the event of a biological attack, a series of sensors positioned over a wide area could determine the direction and speed of cloud of poisonous chemicals, which authorities could then use to for evacuation purposes.

Finally, a third application involves the use of wireless sensors for “drive by wireless” applications in which the wireless nodes measure and control the various systems in the vehicle and communication to the central processor is done through wireless connectivity. By reducing the cabling, the vehicle runs more efficiently due to the decreased weight which can be quite substantial for vehicles such as airplanes.
Recently, I had the opportunity of visiting several universities doing pioneer work in this area. At Virginia Tech University, I met with the team putting together the
JOUSTER -- Joint Unmanned System Test Experimentation and Research program. The program provides a facility for supporting unmanned system experimentation. They have a 1200 acre site which includes on-road and off-road terrain, site instrumentation, and wireless networking.

I also met with at Dr. David Nagel at George Washington University who researches the impact of security procedures (e.g. encryption) on the performance of a wireless sensor network.
In particular he focuses on ship container and home network applications. He believes there will be a convergence of RFID (What is it?), GPS (Where is it?) and Sensor networks (What is its condition?) in these networks.

If you are working in the area of Ad Hoc Networks or Wireless Sensor Networks, I would like to hear from you. Please email me at hall.martin@ni.com.

Best regards,
Hall T. Martin