Re: [Discuss-gnuradio] OFDM Blocks

[Martin Braun]

Nashid,

please stick to the mailing list.

There's lots of tutorials out there to get the OFDM blocks running with
the default settings. Once you have that going, work your way from there.

M

On 08/03/2014 09:42 PM, Md. Anjum wrote:
> Thanks you Martin for your help.
> Your answer clarifies many queries. But I'm still now struggling with
> OFDM Transmitter and Receiver blocks.
> I attached a very simple example of OFDM Transmitter and Receiver block.
> Please find the attached .grc file. But this very simple example does
> not works, it does not show any sending or receiving signal. Could you
> help me to find the explanation please?
> 
> Best regards
> Nashid Anjum
> 
> 
> 
> On Fri, Jul 25, 2014 at 3:06 AM, Martin Braun <address@hidden
> <mailto:address@hidden>> wrote:
> 
>     On 07/25/2014 01:18 AM, Md. Anjum wrote:
>     > Hello,
>     >
>     > I'm working with USRP OFDM blocks. I'm confused about how to use
>     > built-in OFDM Transmitter and OFDM Receiver blocks.
>     >
>     > 1. How to set the fields- occupied carriers, pilot carriers, sync word
>     > and pilot symbols?
> 
>     Before I go into this, did you read the manual page? If yes, what
>     specifically is unclear? Also, did you go through the examples in
>     gr-diigtal/examples/ofdm?
> 
>     > 2. I'm using N200 board. I transmitted signal using OFDM Mod block UHD
>     > Sink block. It seems it       transmits properly. But when I
>     receive the
>     > signal using OFDM Demod and UHD Source block then it   looks the
>     signal
>     > is not received properly. The received signal shows a quite different
>     > pattern than the transmit one. It looks it receives something
>     different
>     > signal, not the transmitted one. Note: I'm using same USRP board to
>     > transmit and receive signal simultaneously.
> 
>     I recommend sticking to the OFDM Transmitter and -Receiver blocks.
> 
>     > 3. Again, I need to control the frequency offset of the
>     subcarriers. How
>     > can I do that using the built-in blocks?
> 
>     Do you mean the sub-carrier spacing? If so, of course you can
>     control that.
> 
>     > 4. And is there any way to control the transmit signal power?
> 
>     There are many ways to control the transmit power. You can vary the
>     signal amplitude digitally, you can increase the tx gain... just make
>     sure you don't distort your signal.
> 
> 
>     > 5. Well, does the OFDM Mod2 block works? If it is then how to use
>     that one?
> 
>     No, it doesn't. That's actually spurious XML.
> 
>     M
> 
>     >
>     > I already asked a lot of questions. Thanks for your patience.
>     >
>     >
>     > Regads
>     > Nashid Anjum
>     > Graduate Student
>     > South Dakota School of Mines and Technology
>     >
>     >
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