1 CEN6930: Wireless Experiments Background Wireless Measurements: Shao-Cheng Wang ( [email protected] )[email protected] Instructor: Dr. Helmy.

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CEN6930: Wireless Experiments Background

Wireless Measurements: Shao-Cheng Wang ( [email protected] )

Instructor: Dr. Helmy

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Part I: Wireless MeasurementsAgenda

• Introduction

• Wireless measurement fundamentals

• Tools/Procedures

• Reference

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How does a coverage map look like?

http://www.ittc.ku.edu/wlan/images.shtml

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coverage maps (cont’d)

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Wireless fundamentals: SNR v.s. Distance

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Wireless fundamentals: SNR v.s. Performance

SNR v.s. Delivery ratio(emulator)

SNR v.s. Delivery ratio(real measurement)

SNR v.s. TCP Tput(real measurement)

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Tools (cont’d)

• HP iPAQ: WiFiFoFum

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Tools

• Site-surveyer: Netstumbler (www.netstumbler.com)– Signal (in –dbm), SNR– AP MAC, SSID

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Indoor measurements Outdoor measurements

Wireless coverage experiments

Indoor measurements

Outdoor measurements

Logistics• Exp: starts this week (?)• Form groups: 4~5 ppl• Equipment checkout: CSE401

– Bring your ID– 11am~6pm, no overnight checkout

• Preparations– Materials

• link: http://www.cise.ufl.edu/~sw0/cen6930/

– Software

• Wififofum: pocket pc wifi scannerhttp://www.aspecto-software.com/rw/applications/wififofum/

• Knsgem: convert wifi scanner output to google earth kml• Google earth

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Potential experiment topics• Coverage Map:

– Create a coverage map of your choice: • SNR (enhanced with levels, dbm #’s)• SNR variations (weather, day/night)• Performance map• Find holes, additions, tech heterogeneity (11a/b/g/e/n) etc.

(please coordinate between groups for the area of interest)

– Reason about your choice and the implications of practicability– Observations/Surprises?

• AP Hunting/Coverage/Handover– Locate APs in some specific areas/buildings– Create an AP-specific coverage map– AP-coverage/handover map for routes on campus– Observations and discussions about the AP planning (evaluation

of planning, tradeoffs, applications, etc.)

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Reference• Simon Byers and Dave Kormann, “802.11b access point mapping,”

Communications of the ACM, May 2003.• Daniel Aguayo, John Bicket, Sanjit Biswas, Glenn Judd, Robert

Morris, “Link-level Measurements from an 802.11b Mesh Network,” SIGCOMM 2004, August 2004

• Hiroto Aidal, Yosuke Tamura2, Yoshito Tobe2, Hideyuki Tokudal, “Wireless Packet Scheduling with Signal-to-Noise Ratio Monitoring,” LCN 2000