Re: [Discuss-gnuradio] (no subject)

[Marcus Müller]

Hi GP,

ofdm_loopback.grc covers only the physical aspects of the transmission. What you are describing is a flow control problem; you'd need to figure out yourself how to make your data stream fit into the packets. A typical way would be to send the length of your file, and then just fill up the last packet with random data/redundancy/zeros; however, what will happen if you lose one packet?

In a real-world application, you'll have some content header, you'd have channel coding/FEC, possibly some ARQ scheme, in case of multiple users a MAC etc; whereas you "only" stream bits out of a file. Complete, versatile transmission systems is what people build atop of transmission systems such as the GNU Radio-supplied OFDM packet transmitters (which primarily serve as good examples and showcases for the mechanisms involved).

Hope that was a little helpful,
Greetings,
Marcus

On 03.07.2014 00:01, GP 2014 wrote:

When I ran the example ofdm_loopback.grc,
i used a file source to send data through the transmitter and checked the
output after the receiver in a file sink ;
i found that if the packet required to be sent is less than the defined
packet_length ; then the packet is not sent ?
how to send the last packet in this case ?

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