Wi-Sleep:%20Contactless%20Sleep%20Monitoring%20via%20WiFi%20Signals

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Wi-Sleep Contactless Sleep Monitoring via WiFi
Signals

• Xuefeng Liu1, Shaojie Tang2, Jiannong Cao1, Jiaqi
  Wen1
• Dept. of Computing, The Hong Kong Polytechnic
  University
• Jindal School of Management, UT Dallas
• Presenter Qixin Wang1

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Outline

• Motivation

• Related works

• Breath detection using WiFi signals

• Experiment

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Sleep Monitoring Systems Class 1
Obtrusive to the users
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Sleep Monitoring Systems Class 2
Privacy issue
High cost
Affected by light
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Low cost
Touch-less
Environmentally robust
Privacy- preserved
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Can Wireless Radios Work?
Low cost Non-intrusive Environmentally robust No
privacy concerns
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Existing works
Using RSSI (Received Signal Strength Indicator)
for tracking respiration

• Drawbacks
• Low sensitivity ? Low accuracy
• The effect of different sleeping postures is not
  investigated

O. J. Kaltiokallio and et al., Non-invasive
respiration rate monitoring using a single cots
Tx-Rx pair, in IPSN 2014.
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Any better wireless features than RSSI ?
Packet loss rate (PLR) LQI (Link quality
indicator)
?
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(No Transcript)
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Channel State Information (CSI)
CSI Using Intel Wi-Fi Wireless Link 5300
802.11n MIMO radios, can provide real-time
channel state for 30 subcarrier groups
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CSI Amplitude and Phase
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(No Transcript)
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Why CSI Works?
Reflection Diffusion Scattering
NLOS ? ? NLOS
LOS ? ? NLOS
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The CSI Data Processing
Outlier removal using the median filter
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The CSI Data Processing
Interpolation and wavelet-based noise filtering
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The CSI Data Processing
Why choose wavelet filter instead of a general
low-pass filters?
Wavelet filter can preserve edge information,
which will be utilized when detection postures
changes.
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The CSI Data Processing
Channel Selection using the Recurrence Plot
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The CSI Data Processing
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The CSI Data Processing
Final result
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The Effect of Sleeping Positions
6 sleeping positions
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The Effect of Sleeping Positions
When TX and RX are at the two sides of the person
Channel Selection using the Recurrence Plot
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The Effect of Sleeping Positions
The rationale
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The Effect of Sleeping Positions
When TX and RX are at the same side of the person
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The Effect of Sleeping Positions
Three pairs of TX-RX
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The Effect of Sleeping Positions
Identifying Sleeping Positions via difference in
periodicity level
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Experimental Results
False positives and negatives
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Experimental Results
Tracking respiration with fixed sleeping positions
TX1-RX1 (same side)
TX1-RX2 (different side)
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Experimental Results
Identifying sleeping positions
A sleep on the back B sleep on the left
side C sleep on the right side
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THANK YOUQA