PowWow

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PowWow hardware platform

PowWow (Power Optimized Hardware and Software FrameWork for Wireless Motes) is a wireless sensor network (WSN) mote developed by the Cairn team of IRISA/INRIA. The platform is currently based on IEEE 802.15.4 standard radio transceiver and on an MSP430 microprocessor. Unlike other available mote systems, PowWow offers specific features for a very-high energy efficiency:[1]

Hardware[2][edit]

PowWow hardware platform is composed of a motherboard including an MSP430 microcontroller and of other daughter boards such as the radio transceiver board, the coprocessing board and some sensor and energy harvester boards.

PowWow synoptic.png

Processing motherboard[edit]

  • TI MSP430 low-power microcontroller
  • MSP430F1612 version, 8 MHz clock
  • 55KB of flash memory, 5KB of on-chip RAM
  • 330uA at 1 MHz and 2.2 V in active mode, 1.1uA in standby mode
  • P1, P2 connectors for extension
  • JTAG, RS232 and I2C interfaces

Radio Board[edit]

  • TI CC2420 RF transceiver
    • Digital direct sequence spread spectrum baseband modem
    • Single-chip 2.4 GHz IEEE 802.15.4 compliant
    • Spreading gain of 9 dB, data rate of 250 kbit/s
  • Hardware support for packet handling, data buffering, burst transmissions, data encryption, data authentication, clear channel assessment, link quality indication and packet timing information

Co-processing Board[edit]

A co-processing board can be added to the motherboard on P1, P2 connectors. This board provides dynamic voltage scaling and hardware acceleration to increase the energy efficiency of the network.

  • Power Mode Management (PMM)
    • Low-Power Programmable Timer for Wake-up period
    • MAX6370, 8uA
  • Dynamic Voltage and Frequency Scaling (DFVS)
    • Programmable Clock
      • LTC6930, 490uA
      • 8 MHz divided by 1 to 128
    • Programmable DC/DC converter
      • TPS62402/TPS61030
  • FPGA co-processing
    • Low-power Igloo FPGA from Actel
    • AGL125: 130 nm, 125 kgates, 32kbits on-chip RAM, 1 kbits Flash, PLL for clock management.
    • Supply voltages 0 to 1.65V
    • Power consumption: 2.2 uW, 16 uW, 1 to 30 mW in sleep, freeze, run modes
    • e.g. Viterbi decoder for link layer implemented on the FPGA consumes 5 mW

Networking[edit]

  • MAC layer: preamble sampling protocol

PowWow uses RICER[3] protocol proposed by UC Berkeley to reduce the time spent in radio reception (RX) mode. This protocol consists in cycled rendez-vous initiated by a wake-up beacon from potential receivers. Thanks to this method, nodes are sleeping most of the time, hence saving energy.

PowWow uses a simple geographical routing protocol.

    • Each node has (x,y) coordinates
    • Next node for hop transmission is chosen in the neighbors as the nearest to the destination

in the sense of Euclidean distance

  • Neighbor table management
    • A neighbor is a node in the radio range of a node
    • Neighbors are discovered at power-up and on regular time period
  • Transmission modes
    • Broadcast
      • Direct transmission to {neighbors}, no ACK
    • Flooding
      • Broadcast a packet to all network nodes, no ACK
    • Direct Hop with/without ACK
      • Direct transmission to a specific neighbors with/without ACK
    • Robust Multi-Hop
      • Multi-hop transmission to a specific node in the network
      • Each hop is with ACK
      • Uses node address

Software[edit]

PowWow software distribution provides an API organized into protocol layers (PHY, MAC, LINK, NET and APP). The software is based on the protothread library of Contiki, which provides a sequential control flow without complex state machines or full multi-threading.

  • Memory efficiency: 6 Kbytes (protocol layers) + 5 Kbytes (application)
  • Over-the-air re-programmation (and soon reconfiguration)

Development Tools[edit]

Availability[edit]

The first version of PowWow were released July 2009. PowWow V1 includes the motherboard, the radio board and the software. A first prototype of the coprocessing board is currently available but not yet distributed. PowWow V2 is under development.

PowWow is delivered as an open-source hardware and open source software under the GPL license.

External links[edit]

Sources[edit]

  1. ^ O. Berder and O. Sentieys. Powwow : Power optimized hardware/software framework for wireless motes. In Proc. of the Workshop on Ultra-Low Power Sensor Networks (WUPS), co-located with Int. Conf. on Architecture of Computing Systems (ARCS 2010), pages 229–233, Hannover, Germany, February 2010.
  2. ^ http://powwow.gforge.inria.fr/subpages/Hardware.html
  3. ^ Lin, E.-Y. A., Rabaey, J. M., Wolisz, A. : Power-efficient rendez-vous schemes for dense wireless sensor networks. In Proc. of the IEEE Int. Conf. on Communications, Paris, France, June 2004.
  4. ^ M.M. Alam, O. Berder, D. Menard, T. Anger, and O. Sentieys. A hybrid model for accurate energy analysis of wsn nodes. EURASIP Journal on Embedded Systems, 2011.