Hello everyone,
I was running the examples proposed ( bbn_80211b_tx.py & bbn_80211b_rx.py ) and I noticed that something was wrong. First of all, I've installed succesfully GNU Radio toolkit and BBN project.
The issue is:
I run bbn_80211b_tx.py (transmitter) with an USRP2 in a computer with random arguments (f=2.4GHz, ...) and at the same time I run bbn_80211b_rx.py (receiver) with another USRP2 in another computer with random arguments too. And the result is....
=========
TRANSMITTER
=========
$ ./bbn_80211b_tx.py
>>> gr_fir_ccf: using SSE
Network interface: eth0
USRP2 address: xx:xx:xx:xx:xx:xx (MAC hidden)
Using TX d'board id 0x0060
Tx baseband frequency: 2.4G
Tx DUC frequency: 0
Tx residual frequency: 0
Tx interpolation rate: 4
Samples per data bit: 25
DATA:
Hello world
Four score ...
[11 textlines]
... shall not perish from the earth.
Sending pkt 0
Sending pkt 1
Sending pkt 2
Sending pkt 3
Sending pkt 4
Sending pkt 5
Sending pkt 6
Sending pkt 7
Sending pkt 8
Sending pkt 9
======
RECEIVER
======
./bbn_80211b_rx.py
>>> gr_fir_ccf: using SSE
Recieved (short) header!
signal: 0x50
service: 0xCD
length: 0x3ADD
crc: 0x7B3B
Calculated crc: 0xADB7
*** BAD CRC ***
Recieved header!
signal: 0x1B
service: 0x26
length: 0xCB69
crc: 0xD9EA
Calculated crc: 0xE01A
*** BAD CRC ***
Recieved (short) header!
signal: 0x00
service: 0xA5
length: 0x111D
crc: 0xCA9E
Calculated crc: 0xEE55
*** BAD CRC ***
(... and more) still receiving frames when the transmitter isn't running.
I've been reading the code of the tx and don't see where I could test the value of the fields (signal, service, length, crc) have each packet.
Am I running propertly the examples? I don't have too much experience with this code.
Why rx calculates always a bad CRC?
Thank you very much for your help,