rss step size: 1 db is not enough!...applications of rf sensing q. pu et al. \whole-home gesture...

$: RSS Step Size: 1 dB is not Enough!...Applications of RF Sensing Q. Pu et al. \Whole-home gesture recognition using wireless signals", MOBICOM 2013. O. Kaltiokallio et al. \Non-invasive$
RSS Step Size: 1 dB is not Enough!

Anh Luong1, Alemayehu Solomon Abrar1,Thomas Schmid1, Neal Patwari1,2

1University of Utah, 2Xandem Technology

HotWireless’16

A. Luong, A. Abrar, T. Schmid, N. Patwari RSS Step Size: 1 dB is not Enough! October 3rd, 2016 1 / 20

Applications of RF Sensing

Q. Pu et al. “Whole-home gesturerecognition using wireless signals”,

MOBICOM 2013.

O. Kaltiokallio et al. “Non-invasiverespiration rate monitoring using a single

COTS TX-RX pair”, IPSN 2014.

W. Wang et al. “Understanding andmodeling of WiFi signal based humanactivity recognition”, MOBICOM 2015.

Future: Ubiquitous RF Sensing


Standard RF Sensors


RF Sensing Tradeoff Space


RF Sensing: sub-dB


Outline

1 sub-dB

2 Breathing Monitoring

3 Gesture Recognition

4 Conclusion


sub-dB CC1200 Prototype

Processor:

CC1200 Evaluation Board

Beaglebone Black (BBB)

Datasheet:

12 bits / 0.0625 dB

Empirical study:4 least significant bits / 1dBIQ Sample

17 bits Magnitude

Programable Real-time processingUnit (PRU)348 samples per sec


RSS Calculation and Verification

RSS =∑K

n=0 |Magnituden|2K − G

with K samples, G amp gain

Test with known generated signal


sub-dB Errors

Time (s)

0.2 0.4 0.6 0.8 1 1.2 1.4

Pow

er

(dB

)

-0.6

-0.4

-0.2

0

0.2

0.4

0.6

Sub-dB

1 dB

sub-dB MME: 0.013 dB 1dB: 0.25dB


Outline

1 sub-dB



4 Conclusion


Breathing Monitoring

0 5 10 15 20 25 302.22

2.24

2.26

2.28

2.30

2.32

2.34

2.36

RSS (dBm)

1e10

0 5 10 15 20 25 30Time (sec)

620

640

660

680

700

720

RIP belt

Experimental Setup:

CC1200 TX 434 MHz, sub-dB RX

Ground truth via respiratory inductance plethysmography (RIP) belt


Breathing Monitoring Algorithm

sn∑|sn|2 Filter FIFO DFT Peak f̂

0.1 0.2 0.3 0.4 0.5 0.6Frequency (Hz)

0

5000

10000

15000

PSD


Oversampling & Quantization for Breathing

For breathing monitoring, high accuracy requires:

0

1

2

3

4

5

6

7

8

9

34

8

17

4

11

6

87

58

43

.5

38

.67

29

21

.75

19

.33

14

.5

9.6

7

7.2

5

4.8

3

2.4

2

Err

or

(bp

m)

Hz

PSD RMSPSD MACB RMS

CB MA

0

1

2

3

4

5

6

7

8

9

10

1 1/2 1/4 1/8 1/16 1/32 1/64 1/128

Err

or

(bp

m)

Step Size (dB)

PSD RMSPSD MACB RMS

CB MA

Sampling rate≥29 Hz

Quantization step size≤1/16 dB(≥ 12 bits)


Outline

1 sub-dB



4 Conclusion


Gesture Recognition

0.0 0.5 1.0 1.5 2.0Time (s)

−23.10

−23.05

−23.00

−22.95

−22.90

−22.85

−22.80

−22.75

RSS (

dB

m)

Punch

0.0 0.5 1.0 1.5 2.0Time (s)

−22.20

−22.15

−22.10

−22.05

−22.00

−21.95

−21.90

−21.85

−21.80

RSS (

dB

m)

Kick

0.0 0.5 1.0 1.5 2.0Time (s)

−23.2

−23.1

−23.0

−22.9

−22.8

−22.7

−22.6

−22.5

−22.4

RSS (

dB

m)

Zoom in & Zoom out

0.0 0.5 1.0 1.5 2.0Time (s)

−23.2−23.1−23.0−22.9−22.8−22.7−22.6−22.5−22.4−22.3

RSS (

dB

m)

Bowling


Gesture Recognition Evaluation

8 9 10 11 12 13 14 15 16Quantization bits

30

40

50

60

70

80

90

100

Accuracy (%

)

Two gesturesThree gesturesFour gestures

Features:

Variance

Skewness

8 percentiles (5th to 95th)

PSD for 3 different bands


Outline

1 sub-dB



4 Conclusion


Recommendations

Chip Designer:I smaller step size

(1/16 dB or 0.0625dB)

Application Designer:I Pick IC with 12 bits RSSII IQ Sample


Conclusion

Ubiquitous RF Sensing


Thank you

This material is based upon work supported bythe U.S. National Science Foundation

under Grant Nos. #1329755 and #1407949.

Visit span.ece.utah.edu for more information

Breathing Monitoring Code is available at:https://github.com/SPAN-UofU/rub

PRU Code is available at:https://bitbucket.org/anh_luong/pru


span.ece.utah.edu

https://github.com/SPAN-UofU/rub

https://bitbucket.org/anh_luong/pru

rss step size: 1 db is not enough!...applications of rf sensing q. pu et al. \whole-home gesture...

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