Re: [Discuss-gnuradio] gr-ieee802_11 not able to send or receive packets.

[Anshul Thakur]

Hi,

I have for now circumvented the problem. But I did try looking into the correlation values by logging the correlation after the divide block into a file and inspecting the values in Matlab.

Here are some statistics:

Contiguous samples considered:  4.096e8;

# of samples with correlation > 0.7 : 2241

# of samples with correlation in (0.6, 0.7]: 2405

# of samples with correlation in (0.5, 0.6]: 14998

Threshold value considered in GNU RC block: 0.7

This was after removing all zero padding from delay block.

To get around the problem, I essentially used one of my SDRs as a dummy repeater that just picked all samples at one frequency and transmitted them at a different frequency. In this case, I was able to successfully receive a large number of PDUs and decode them in wireshark. This begs the question as to what I might be doing wrong with the original setup! Some more pointers I could look at?

Also, when I use the Loopback flowgraph with no packet padding, I am unable to receive any PDUs in wireshark. If I add some padding, they are detected. Is that expected behaviour?

I took some pointers from this thread http://gnuradio.4.n7.nabble.com/gr-ieee802-11-receiver-td63486.html#a63508

On 30 March 2017 at 01:56, Bastian Bloessl <address@hidden> wrote:

Hi,

On 03/29/2017 07:01 PM, Anshul Thakur wrote:
>
>
>     You could also test different RX/TX gains and parameters for the padding
>     block (I don't have a BladeRF, so I have no experience). Also assert
>     that there are no overruns or underruns.
>
> I altered the values of gains and padding values (I increased the
> padding values). That didn't seem to help.
>

Actually, I was thinking of decreasing (or completely removing) it. Did
you only try to increase it? Did you do anything else to debug? Like
sending a stream of '0' and monitor the autocorrelation?

Best,
Bastian