cilos: a cdma indoor llitilocalization stsystem
TRANSCRIPT
![Page 1: CILoS: A CDMA Indoor LlitiLocalization StSystem](https://reader031.vdocuments.us/reader031/viewer/2022020622/61ec239a7df24e59ef01d4ca/html5/thumbnails/1.jpg)
CILoS: A CDMA Indoor L li ti S tLocalization System
Waqas ur Rehman, Eyal de Lara, Stefan Saroiu
![Page 2: CILoS: A CDMA Indoor LlitiLocalization StSystem](https://reader031.vdocuments.us/reader031/viewer/2022020622/61ec239a7df24e59ef01d4ca/html5/thumbnails/2.jpg)
Motivation
People spend most of their time indoorsp pGPS does not work indoors
Emergency responseSocial-Mobile ?
?? ??
NavigationMobile GamesAdvertising ?
????? ?
![Page 3: CILoS: A CDMA Indoor LlitiLocalization StSystem](https://reader031.vdocuments.us/reader031/viewer/2022020622/61ec239a7df24e59ef01d4ca/html5/thumbnails/3.jpg)
Fingerprinting – Building a radio mapAP1: -41 AP2: -54
AP4: -35AP5: -64
AP3: -92AP5: 64AP6: -72
AP1: -41 AP2: -54AP3: -92
![Page 4: CILoS: A CDMA Indoor LlitiLocalization StSystem](https://reader031.vdocuments.us/reader031/viewer/2022020622/61ec239a7df24e59ef01d4ca/html5/thumbnails/4.jpg)
Fingerprinting – K Nearest Neighbors
AP1: -40
Current Fingerprint
AP1: 40 AP2: -56AP3: -83
![Page 5: CILoS: A CDMA Indoor LlitiLocalization StSystem](https://reader031.vdocuments.us/reader031/viewer/2022020622/61ec239a7df24e59ef01d4ca/html5/thumbnails/5.jpg)
Signal Fingerprinting Approaches
802.11802.11GSM Signal strength
CDMAPower adaptation to accommodate network loadPower adaptation to accommodate network load
High temporal variations in signal strength Use signal delayUse signal delay
5
![Page 6: CILoS: A CDMA Indoor LlitiLocalization StSystem](https://reader031.vdocuments.us/reader031/viewer/2022020622/61ec239a7df24e59ef01d4ca/html5/thumbnails/6.jpg)
Signal Strength vs. Signal Delay Variations
![Page 7: CILoS: A CDMA Indoor LlitiLocalization StSystem](https://reader031.vdocuments.us/reader031/viewer/2022020622/61ec239a7df24e59ef01d4ca/html5/thumbnails/7.jpg)
CDMA Networks
Base stations share the same spectral bandwidthBase stations are tightly synchronized with GPSBase stations cooperate to transmit pilot signal
32768 symbols64
7
![Page 8: CILoS: A CDMA Indoor LlitiLocalization StSystem](https://reader031.vdocuments.us/reader031/viewer/2022020622/61ec239a7df24e59ef01d4ca/html5/thumbnails/8.jpg)
CDMA Networks
Base stations share the same spectral bandwidthBase stations are tightly synchronized with GPSBase stations cooperate to transmit pilot signal
PN offset
8
PN offset
Key idea: Fingerprint PN offsets
![Page 9: CILoS: A CDMA Indoor LlitiLocalization StSystem](https://reader031.vdocuments.us/reader031/viewer/2022020622/61ec239a7df24e59ef01d4ca/html5/thumbnails/9.jpg)
Data Collection
Condor CDMA scannerCondor CDMA scannerRecorded signal delay and strength over all channels in
DowntownSuburb
6 channels in downtown4 channels in suburb
9
![Page 10: CILoS: A CDMA Indoor LlitiLocalization StSystem](https://reader031.vdocuments.us/reader031/viewer/2022020622/61ec239a7df24e59ef01d4ca/html5/thumbnails/10.jpg)
Average Visible PNs
Interference limits # of visible base stationsWid fi i t i i lti lWide fingerprints require scanning multiple frequency bands
![Page 11: CILoS: A CDMA Indoor LlitiLocalization StSystem](https://reader031.vdocuments.us/reader031/viewer/2022020622/61ec239a7df24e59ef01d4ca/html5/thumbnails/11.jpg)
Localization Algorithms
Simple AlgorithmsSimple Algorithms1 ChannelAll ChannelAll Channel
Feature Selection Algorithms
11
![Page 12: CILoS: A CDMA Indoor LlitiLocalization StSystem](https://reader031.vdocuments.us/reader031/viewer/2022020622/61ec239a7df24e59ef01d4ca/html5/thumbnails/12.jpg)
Localization Error
161820 1 Channel
All ChannelsFeature Selection
121416
met
ers)
Feature Selection
68
10
Erro
r (m
024
0Downtown Suburb
Wide fingerprints helpWide fingerprints helpCareful PN selection critical
![Page 13: CILoS: A CDMA Indoor LlitiLocalization StSystem](https://reader031.vdocuments.us/reader031/viewer/2022020622/61ec239a7df24e59ef01d4ca/html5/thumbnails/13.jpg)
Localization Error CDF (Downtown)
![Page 14: CILoS: A CDMA Indoor LlitiLocalization StSystem](https://reader031.vdocuments.us/reader031/viewer/2022020622/61ec239a7df24e59ef01d4ca/html5/thumbnails/14.jpg)
Comparison with WiFi and GSM
910 WiFi
GSM
678
ers)
CDMA
456
ror (
met
e
23Er
r
01
All Sources Feature Selection
![Page 15: CILoS: A CDMA Indoor LlitiLocalization StSystem](https://reader031.vdocuments.us/reader031/viewer/2022020622/61ec239a7df24e59ef01d4ca/html5/thumbnails/15.jpg)
Floor Level Localization100
%)
60
80
ctio
ns (%
40
60
ful P
redi
20
Succ
essf
0WiFi GSM CDMA
S
![Page 16: CILoS: A CDMA Indoor LlitiLocalization StSystem](https://reader031.vdocuments.us/reader031/viewer/2022020622/61ec239a7df24e59ef01d4ca/html5/thumbnails/16.jpg)
Conclusions
Signal delay is a reliable metric for fingerprinting
Temporal stability
Spatial variability
CIL S hi di f 5 tCILoS achieves median accuracy of 5 meters
Wide signal fingerprints critical to accuracyWide signal fingerprints critical to accuracy
Feature selection really helps
16
y p
![Page 17: CILoS: A CDMA Indoor LlitiLocalization StSystem](https://reader031.vdocuments.us/reader031/viewer/2022020622/61ec239a7df24e59ef01d4ca/html5/thumbnails/17.jpg)
Future Works
Get it to work on commodity cell phoneGet it to work on commodity cell phoneRequires
Access to PN offsetsAccess to PN offsetsScan multiple frequency bands
17