Iterative Decoding for Redistributing Energy Consumption in Wireless Sensor Networks

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Iterative Decoding for Redistributing Energy
Consumption in Wireless Sensor Networks
R. G. Maunder, A. S. Weddell, G. V. Merrett, B.
M. Al-Hashimi and L. Hanzo 23 June 2008
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Overview

• Wireless sensor network scenario
• IEEE 802.15.4 physical layer
• Standard
• Proposed augmentation
• Practical considerations
• Error ratio performance
• Energy savings and complexity
• Conclusions

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Wireless sensor network scenario
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IEEE 802.15.4 physical layer
Standard IEEE 802.15.4 PHY
Proposed augmentation to IEEE 802.15.4 PHY
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Features of the proposed augmentation

• Increased error correction capability
• Fewer retransmissions required
• Reduced transmit power
• Slightly increased transmitter complexity
• Significantly increased receiver complexity

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Wireless sensor network scenario
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Practical considerations

• Header conveys synchronisation sequence and
  payload length
• Both must be recovered before iterative decoding
  can commence.
• Header is transmitted at high power using
  standard PHY
• Payload is transmitted at low power using
  augmented PHY

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Payload error ratio performance
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Transmitter energy savings

• Augmented PHY performs additional processing
• Values conservatively estimated for Chipcon
  CC2430
• 20 reductions in energy consumption

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Receiver complexity costs
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Conclusions

• Physical layer design can be optimised in order
  to benefit particular wireless sensor network
  scenarios.
• Proposed design beneficially redistributes energy
  consumption from source to sink.
• Reduces probability of transmission errors.
• Facilitates reduced transmission power.
• Transforms large payloads (which have a low
  header overhead) from being undesirable to being
  desirable.
• Can interoperate with standard IEEE 802.15.4.

Thank you!