Hello list, I have been fiddling around with USRP2 version of BBN code for a week now. First, one observation I found is: if and only if I set decimation to 4 (i.e., 25Msps), I see almost all of the 1Mbps packets sent by my 802.11 sender. This includes data packets (1400 bytes payload), and IEEE802.11 association/reassociation request packets. I wonder why?
My Specification: - Ubuntu Specification: Ubuntu 10.04 LTS (Lucid Lynx) - Kernel Version: 2.6.32-25-generic - GCC version: 4.4.3 - BBN Code Location: https://www.cgran.org/cgran/projects/bbn_80211/branches/usrp2_version - CPU: (Bo) Intel(R) Core(TM) 2 CPU E8400 @ 3GHz - Memory: 4GB - Wireless Card: Dlink WDA-1320 Atheros Chipset (using madwifi driver) My setup: - Infrastructure mode - AP has a fixed data rate set to 1Mbps so that BBN code receives *ALMOST* all the packets Now, onto my MAIN question: - If the sender at 1Mbps is using DSSS (Barker code), and I am receiving with decimation factor 4 using USRP2, - How many samples per symbol should I expect (I am assuming 1 symbol per bit, thus samples per symbol = samples per bit)? I collect samples using usrp2_rx_cfile.py [rx-file=b.dat] and analyze in Matlab. - So, 25MSps (complex float symbol) sampling rate, how many samples per bit ought I expect. I do b = read_complex_binary('b.dat') in matlab , and look at plot(abs(b))? Thank you in advance for your time.
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