1. 1 CEN6930: Wireless Experiments Background Wireless Measurements: Shao-Cheng Wang ( shaochew@ufl.edu )shaochew@ufl.edu Instructor: Dr. Helmy

2. 2 Part I: Wireless Measurements Agenda Introduction Wireless measurement fundamentals Tools/Procedures Reference

3. 3 How does a coverage map look like? http://www.ittc.ku.edu/wlan/images.shtml

4. 4 coverage maps (cont’d)

5. 5 Wireless fundamentals: SNR v.s. Distance

6. 6 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)

7. 7 Tools (cont’d) HP iPAQ: WiFiFoFum

8. 8 Tools Site-surveyer: Netstumbler (www.netstumbler.com) –Signal (in –dbm), SNR –AP MAC, SSID

9. 9

10. Indoor measurementsOutdoor measurements Wireless coverage experiments

11. Indoor measurements

12. Outdoor measurements

14. 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/http://www.cise.ufl.edu/~sw0/cen6930/ –Software Wififofum: pocket pc wifi scanner http://www.aspecto-software.com/rw/applications/wififofum/ Knsgem: convert wifi scanner output to google earth kml Google earth

15. 15 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.)

16. 16 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