Re: [Discuss-gnuradio] Questions about burst communication

[julian . arnold]

Hi Logan,

The problem is that the USRP does not know where your burst of data starts and how long it is and therefore it will respond with Us as soon as no new data is coming in. In order to tell the USRP how long a packet of data is the USRP sink in GNURadio offers the 'length tag name' property. If you set this to something not empty the USRP sink will work like a tagged stream block and can therefore handle tagged streams properly. 

However, you are reporting to see Os and not Us. That is a little strange. Normally it indicates that your PC is not able to keep up with the processing of the incoming data. This should be more or less independent on weather or not you are transmitting bursty data. 

Are you not seeing any Us and only Os?

Cheers,

Julian

Am 24.09.2015 um 17:20 schrieb Washbourne, Logan <address@hidden>:

Hello all,

I've been trying to modify the chat app tutorial into a system that can utilize USRPs and an acknowledgement system. The acknowledgement system works so far, the RX just sends a pdu back to the TX side saying that it received the message. I am now trying to implement the USRPs to have an over the air system, instead of just using one computer and simulating the channel.

My grc files are on github, https://github.com/loganwashbourne/Logan.git. The modified Chat Receiver and Chat Sanitizer blocks are on the github as well.

My question is, do I need to treat a burst communication system different than a continuous system? My problem is that on each side I am getting O's whenever I start the program, I have tried increasing and decreasing the sampling rate, and I didn't see any change to the output.

I am using the USRP1's, with the RFX2400 daughter boards.

If anyone has any ideas or avenues for me to look into it would be much appreciated.

Logan Washbourne

Electrical Engineering Graduate Student

(Electromagnetics)

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