Project: IEEE P802.15 Working Group for Wireless Personal Area Networks (WPANs)

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• Project IEEE P802.15 Working Group for Wireless
  Personal Area Networks (WPANs)
• Submission Title Non-coherent ranging results
  with a-priori knowledge of noise variance
• Date Submitted 24 June 2005
• Source Ismail Guvenc, Zafer Sahinoglu,
  Mitsubishi Electric
• Contact Zafer Sahinoglu
• Voice1 617 621 7588, E-Mail zafer_at_merl.com
• Abstract This document provides performance
  results of non-coherent ranging receivers, under
  the assumption that noise variance is accurately
  estimated and available a-priori
• Purpose To help objectively evaluate ranging
  proposals under consideration
• Notice This document has been prepared to assist
  the IEEE P802.15. It is offered as a basis for
  discussion and is not binding on the contributing
  individual(s) or organization(s). The material in
  this document is subject to change in form and
  content after further study. The contributor(s)
  reserve(s) the right to add, amend or withdraw
  material contained herein.
• Release The contributor acknowledges and accepts
  that this contribution becomes the property of
  IEEE and may be made publicly available by
  P802.15.

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Option-I (Burst PPM)
Proposed System Parameters (With Same Pulses
per unit time) (by MERL)
The Other Bit
One Bit
Always Empty
Always Empty
Always Empty
8-chip times 150ns
100ns
100ns
8-chip times 150ns
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Energy Detection Receiver Architectures
FT RD
TOA Estimator
I2R
MERL
4
Simulations
Observation window 512ns
TOA Ambiguity 256ns
Ts3 2048ns
Option 3 (16 pulses per 2us)
Option 1 (16 pulses per 2us)
Option 4 (16 pulses per 2us)
Ts1 Ts4 512ns
Since option-3 uses 31 chip sequences, 1984ns
symbol duration is used for option-3 to have
multiples of 4ns sampling duration. However,
total energy used within 4ms duration are
identical for all cases. A training sequence
of all 1s are used. Random training sequence
will introduce self interference that will
degrade the performance.
5
Threshold Selection

• Assume that µn and sn2 mean and the variance of
  the noise respectively
• Probability that a noise only sample greater than
  a threshold e is
• Probability of threshold crossing within K
  consecutive noise only samples
• The corresponding threshold is

PFA
e
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Results

• PFA 0.1, TB 4ns

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Results

• PFA 0.05, TB 4ns

8
Results

• PFA 0.01, TB 4ns

9
Results

• PFA 0.005, TB 4ns

10
Results

• PFA 0.001, TB 4ns

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Results

• PFA 0.1, TB 2ns

12
Results

• PFA 0.05, TB 2ns

13
Results

• PFA 0.01, TB 2ns

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Results

• PFA 0.005, TB 2ns

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Conclusion

• A-priori knowledge of noise variance improved
  ranging performance
• Threshold is set according to the noise variance
  and probability of missing a block, not according
  to the percentage of the highest signal energy
  block
• This made option-4 suffered.
• Option-1 (after processing gain) performed the
  best both in terms of 3ns confidence level and
  mean absolute error (MAE).
• 3ns confidence level can be 90 around 15dB, at
  4ns sampling interval, and around 13dB at 2ns
  sampling interval
• MAE is around 2ns at 15dB at 4ns sampling
  interval, and at 13dB at 2ns sampling interval