WiSMART Exercise: Wireless Channel Measurement

1. WiSMART Exercise:Wireless Channel Measurement Amit K. Vyas (amitvyas@cs.stanford.edu) Fouad A. Tobagi (tobagi@stanford.edu) Stanford University Wireless Mesh networks (AIIT)

2. Objective • To illustrate the use of WiSmart • Wireless Stanford Measurement Analysis and Research Tool • Four Parts • Configuring the Laptops • Taking Measurements • Data Analysis • Plotting Results Wireless Mesh networks (AIIT)

3. Scenarios • The class will be divided into four groups • Each group will conduct 4 measurement experiments • Separation between laptops ranging from 1 to 4 units • Time duration = 5 minutes each Wireless Mesh networks (AIIT)

4. WiSMART Package Details • Download the latest WiSMART package from the class website, and extract it under C:\ • WiSmart instructions can be found at C:\WiSmart\WiSmart_Instructions.txt • Requirements • Building the Driver • First-time Configuration • Regular Configuration after Reboot • Measurements/Testing • Data Analysis • Plotting Results of SNR & PER over Time (using Matlab) Wireless Mesh networks (AIIT)

5. Configuring the Laptops • Start the laptop • cd WiSmart/madwifi • ./ra.sh • ./ia_adhoc.sh • iwconfig ath0 rate 24M • Create directory for the tests: • mkdir ~/tests • cd ~/tests Wireless Mesh networks (AIIT)

6. Taking Measurements • Instructions below are for test 1 from laptop 111 to 112. Change accordingly for tests 1-4 and laptops 111-118 • Run “~/WiSmart/traffic/wismart_traffic” on both your laptops • It will print out the current time in seconds, say x • Choose a start time for the tests by adding some time to finish configuration on both laptops. e.g. x+120 • On client/TX laptop (111), run “~/WiSmart/traffic/wismart_traffic ath0 192.168.50.112 1472 5 300 <test_start_time> cli wismart_on ~/WiSmart/madwifi/tools/wismart test1” • On server/RX laptop (112), run “~/WiSmart/traffic/wismart_traffic ath0 192.168.50.112 1472 5 300 <test_start_time> srv wismart_on ~/WiSmart/madwifi/tools/wismart test1” Wireless Mesh networks (AIIT)

7. Measurement Results • If the measurement experiment was successful, it should create four non-empty files: • test1_cli_tx.txt – Transmission Statistics of Client • test1_cli_rx.txt – Reception Statistics of Client • test1_srv_tx.txt – Transmission Statistics of Server • test1_srv_rx.txt – Reception Statistics of Server • Since our traffic is from client to server, the largest files should be: test1_cli_tx.txt and test1_srv_rx.txt Wireless Mesh networks (AIIT)

8. Data Analysis • Once all four tests are over, using USB stick copy the client files from the client laptop (111) to server laptop (112) • If your USB stick is not detected, contact me • Move all files to ~/tests • Run “~/WiSmart/analyzer/wismart_analyzer test1_cli_tx.txt test1_srv_rx.txt output_test1 –t c1 –r c2 –i 5 • Here, output_test1 is output file prefix • c1 stands for 111, c2 stands for 112 • used to specify MAC addresses of involved wireless cards in order to detect errors if unexpected devices are detected • This will result in two files: output_test1_tx.txt and output_test1_rx.txt for client and server respectively Wireless Mesh networks (AIIT)

9. Plotting Results • Copy the two output files to your PC in the directory C:\WiSmart\plot_results • Start Matlab • cd C:\WiSmart\plot_results • Run “plot_wismart_snr_per_results” • This should plot the SNR and PER over time, where each point is obtained by averaging samples over one second intervals. Wireless Mesh networks (AIIT)

10. Thank You !! Wireless Mesh networks (AIIT)