Wireless technology is having a profound impact on the embedded systems market. Low cost, low power, easy to implement, large scale wireless sensor networks are enabling innovative applications, as well as significant improvements in existing systems.
Generating the most interest and potential are wireless sensor networks that can assemble and reconfigure themselves. Consider a wireless sensor network that can run without a human administrator that will reconfigure itself automatically if nodes on the network fail. It might comprise tens of thousands of nodes spread over a huge area, yet will operate for years with minimal maintenance. Or consider an ad hoc network that builds or reconfigures itself, as required, from any suitable devices in range or which move into range.
Autonomous, semi autonomous, self building reconfigurable wireless sensor networks are quite different from domestic or office wireless networks. The building blocks of a wireless sensor network can be extremely simple devices, sometimes called sensor motes, typically comprising a sensor, microcontroller and radio – effectively a miniature embedded system. Power may be via a battery or, increasingly, via energy harvesting. Typically small, low cost and low power, they do their own routing and can communicate across a potentially vast network by forwarding messages via nearby nodes.
The design challenge is for self building, self managing reconfigurable networks to operate reliably at very low power, inexpensively and on a large scale. The nodes are typically resource constrained and might use different operating systems, connected through different types of network interfaces. Ad hoc networks, accessing mobile nodes, need to be adaptive to changing conditions based on context awareness.
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