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™ 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))?
- How many samples per symbol should I expect (I am assuming 1 symbol
Thank you in advance for your time.