This is my first project in GitHub. The Matlab codes are used for 802.11a signal offline analysis. - Setup one 11a AP and two 11a nodes (using 6MBps); Setup three usrps close to all three nodes (1 AP + 2 Clients) to sniffer physical signals; - Given rxdata sampled using USRP (20MHz), WritePacketOrder2.m will indentify the packet boundary, and store the IDLE+PACKET indentification results; - Given list outputed from WritePacketOrder2.m, FilterPackets.m will indentify well-defined packets (DIFS+T*Slots+PKT+SIFS+ACK), and packets without ACK; Note that the Matlab codes are for 11a signal. For 11b/g signal, you should change parameters in CheckIFSType.m and CheckPACKETType.m. Also, note that ISM crowded spectrum may ruin your measurement. Files: - WritePacketOrder2.m, CheckIFSType.m and CheckPACKETType.m are used for IDLE+PACKET boudary identification using double window sliding approach; - FilterPackets.m is used to filter valid and invalid packets generated by last function. Also, with CheckUsers2.m, it tries to indentify number of users in each packet using LTS correlation result; WriteFinalReport.m is used to write formatted output; - matrix.m is used to model Markov Process that two users exist with fixed CW. Some functions are still in development. If you are interested, please contact me directly. Email: lzyou@smail.nju.edu.cn