Re: [Discuss-gnuradio] BBN 80211b Transmitter with GNURadio 3.2.2 and USRP1

[Smith L.]

Hi Colby,

Were you able to communicate between two USRP2s using bbn 80211
usrp2_version code?

I am not able to receive packets using USRP2 receiver even when other USRP2
is transmitting. Can you please let me know if there are any changes
required to be made in the usrp2_version code or any specific command line
parameters to make this work (i.e. to receive 80211b packets with USRP2 with
another USRP2 transmitting).

Currently, I can only receive beacons from nearby access points using USRP2.

Any input on this issue is appreciated.

Thanks,
Smith


Colby Boyer-2 wrote:
> 
> Cool to hear about the OFDM 802.11 project.
> 
> When I was working with the USRP2 version, I was only able to get two
> USRP2s
> to talk to each other. I can't remember if I was able to get it to decode
> packets from a chipset, that was a year ago.....
> 
> I do remember that sometime ago, there was further discussion on getting
> the
> spreading waveform correct since it was not matching the 802.11 roll off
> specs. My first guess is to check the match filter being used (if you can
> capture the chipset's waveform).
> 
> On Thu, May 20, 2010 at 1:08 PM, George Nychis <address@hidden> wrote:
> 
>>
>>
>> On Thu, May 20, 2010 at 3:14 PM, Smith L. <address@hidden> wrote:
>>
>>>
>>> Thanks for the help, Doug.
>>>
>>> I do have two USRP2s and hence was also working on the usrp2_version
>>> code.
>>> I
>>> have both the transmitter and receiver code individually working
>>> correctly
>>> with USRP2. However, the receiver is not able to receive the packets
>>> correctly from the transmitter (i.e in case of USRP2). I always get bad
>>> CRC
>>> message.
>>>
>>> I have looked up the forum and everybody seem to stuck with the same
>>> problem. Is there any work around to solve this problem?
>>>
>>> From the forum discussion, it seems that one of the issues is the
>>> preamble.
>>>
>>> Any idea how to make synchronize the receiver so that it can receive the
>>> packets from USRP2 transmitter using bbn code.
>>>
>>>
>> I struggled with this for quite a while.  I never understood exactly
>> where
>> a standard card was not able to decode it.  Large frequency offset maybe? 
>> I
>> never got a single packet through.
>>
>> Can I suggest something?  Try out this 802.11 project:
>> https://www.cgran.org/wiki/ftw80211ofdmtx
>>
>> They definitely claim that a standard NIC can decode the packets, but I
>> never personally got around to trying it.  The code seemed pretty clean,
>> and
>> I was able to use it to generate proper packet signatures... so the
>> modulation is definitely correct.
>>
>> - George
>>
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>>
>>
> 
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