CEN 6930 Wireless Experiments Background Wireless Measurements ShaoCheng

CEN 6930: Wireless Experiments Background Wireless Measurements: Shao-Cheng Wang ( shaochew@ufl. edu ) Instructor: Dr. Helmy 1

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

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

coverage maps (cont’d) 4

Wireless fundamentals: SNR v. s. Distance 5

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) 6

Tools (cont’d) • HP i. PAQ: Wi. Fo. Fum 7

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

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Wireless coverage experiments Indoor measurements Outdoor measurements

Indoor measurements

Outdoor measurements

Logistics • Exp: starts this week (? ) • Form groups: 4~5 ppl • Equipment checkout: CSE 401 – Bring your ID – 11 am~6 pm, no overnight checkout • Preparations – Materials • link: http: //www. cise. ufl. edu/~sw 0/cen 6930/ – 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

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 (11 a/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. ) 15

Reference • Simon Byers and Dave Kormann, “ 802. 11 b 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. 11 b Mesh Network, ” SIGCOMM 2004, August 2004 • Hiroto Aidal, Yosuke Tamura 2, Yoshito Tobe 2, Hideyuki Tokudal, “Wireless Packet Scheduling with Signal-to-Noise Ratio Monitoring, ” LCN 2000 16