Section: Software
PowWow: Power Optimized Hardware and Software FrameWork for Wireless Motes
Participants : Olivier Sentieys [ correspondant ] , Olivier Berder, Thomas Anger, Arnaud Carer, Jérôme Astier, Samuel Mouget, Adeel Pasha, Steven Derrien.
PowWow is a hardware and software platform designed to handle wireless sensor network (WSN) protocols and related applications. Based on an asynchronous rendezvous medium access (MAC) protocol, geographical routing and protothread library, PowWow requires a lighter hardware system than Zigbee [85] to be processed (memory usage including application is less than 10kb). Therefore, network lifetime is increased and price per node is significantly decreased.
Cairn 's hardware platform (see Figure 3 ) is composed of:
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The motherboard, designed to reduce power consumption of sensor nodes, embeds an MSP430 microcontroller and all needed components to process PowWow protocol except radio chip. JTAG, RS232, and I2C interfaces are available on this board.
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The radio chip daughter board is currently based on a TI CC2420.
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The coprocessing daughter board includes a low-power FPGA which allows for hardware acceleration for some PowWow features and also includes dynamic voltage scaling features to increase power efficiency. The current version of PowWow integrates an Actel IGLOO AGL250 FPGA and a programmable DC-DC converter. We have shown that gains in energy of up to 700 can be obtained by using FPGA acceleration on functions like CRC-32 or error detection with regards to a software implementation on the MSP430.
PowWow distribution also includes a generic software architecture using event-driven programming and organized into protocol layers (PHY, MAC, LINK, NET and APP). The software is based on Contiki [95] , and more precisely on the Protothread library which provides a sequential control flow without complex state machines or full multi-threading.
To optimize the network regarding a particular application and to define a global strategy to reduce energy, PowWow offers the following extra tools: over-the-air reprogramming (and soon reconfiguration), analytical power estimation based on software profiling and power measurements, a dedicated network analyzer to probe and fix transmissions errors in the network. More information can be found at http://powwow.gforge.inria.fr .
