Re: [Discuss-gnuradio] OFDM Implementation

[waqasme]

Yes johnny for a while i need only OFDM transmitter and reciever  via USRP
for my project. I just want that this OFDM system can transmit and receive
via USRP, that is my aim at the moment.  
Thanks once again for your detailed clarification. i will try that and let
you know the results. 
Thank you so much for your help i really appriciate that.

Regards,
Waqas.

Tuan Ta-2 wrote:
> 
> As far as I know there's no open source code for an OFDM transceiver
> available. I was trying to build one half a year back but wasn't
> successful
> before I had to move on to something else. The benchmark_ofdm code will
> give
> you a simplex OFDM system. Ie you can run the transmitter on 1 USRP and
> receiver on another.
> 
> Ie. run this on 1 USRP
> ./benchmark_ofdm_tx.py -f 2.412G
> 
> And this on the other
> ./benchmark_ofdm_rx.py -f 2.412G
> 
> The value of the frequency depends on the daughterboards you're using. If
> you're using USRP1 make sure the decimation rate is 1/2 of the
> interpolation
> rate as the ADC is 2 times faster than the DAC on the USRP1 (or the other
> way around, you should chek that).
> 
> Watch out for the frequency offset, it killed the system for me. If the
> above doesn't work, run the transmitter on 1 USRP and usrp_fft.py on the
> other. Check the center frequency of the FFT plot and manually adjust the
> receiver center frequency. I used the RFX2400 boards and the offset for me
> was ~ 40kHz.
> 
> Good luck,
> Johnny
> 
> 
> 
> On Fri, Sep 9, 2011 at 2:30 AM, sumitstop
> <address@hidden>wrote:
> 
>>
>> http://pwnhome.files.wordpress.com/2011/04/simple_transceiver1.png
>> see carefully....... it has a gmsk modulator in the bottom.u can make the
>> bottom modulator part in another pc
>>
>> benchmark programs are quite good to start with...
>> u can type benchmark_ofdm.py -h to see all the parameters u can play
>> with.
>>
>>
>> waqasme wrote:
>> >
>> > And sorry to mention in the last mail that i will be suing USRP 1 .
>> >
>> > waqasme wrote:
>> >>
>> >> Hi Sumit,
>> >> Thank you so much for your quick response. yah i understand what your
>> >> saying and i am trying to understand this document but it doesnot help
>> >> much . As you mentioned use the same Tranceiver setup and only replace
>> >> OFDM blocks with that. My question is in this basic tranciver diagram
>> the
>> >> used two UHD's source and sink and in the middle they use GMSK
>> >> Demodulator right. but they didnot use any modulator any where in the
>> >> design. Now i am confused what blocks i have to replace with OFDM
>> >> blocks??? Please try to explain in bit detail so i can design it
>> properly
>> >> .
>> >> OR you mentioned other option that use benchmark_OFDM.py file .
>> Somebody
>> >> already told me about this benchmark file. but its just C++ code . i
>> am
>> >> quite new to GNU radio and dont know much about the functions how it
>> >> works.
>> >> Please let me know how to use that benchmark_OFDM.py file in order to
>> >> make the simulation design? do i have to download the file or what?
>> how
>> >> it works ?? let me know if you know about the process how to compile
>> and
>> >> run that code in GNU radio.
>> >>
>> >> Thanks for ur help and support really appriciate that...
>> >>
>> >> Regards,
>> >>
>> >> Waqas.
>> >>
>> >>
>> >> sumitstop wrote:
>> >>>
>> >>> Try to understand these
>> >>>
>> >>>
>> http://pwnhome.wordpress.com/2011/04/26/intro-to-gnuradio-and-the-usrp-part-5-simple-transceiver/
>> >>>
>> >>> here u need to put those ofdm blocks .. thats it.... also go through
>> >>> some modifications as written in umit,
>> >>>
>> >>>
>> >>>
>> http://pwnhome.wordpress.com/2011/04/19/intro-to-gnuradio-and-the-usrp-part-4/
>> >>>
>> >>> or else work with benchmark_ofdm.py  its very easy.. :)
>> >>>
>> >>> may i know what daughter boards do you have...
>> >>>
>> >>>
>> >>>
>> >>>
>> >>>
>> >>> waqasme wrote:
>> >>>>
>> >>>>
>> >>>> Hello sumit,
>> >>>> Thanks for your help i went through that document that you refered
>> to,
>> >>>> and i tried to implement that OFDM transmitter part. This document
>> only
>> >>>> explain about OFDM flow graph or transmitter. Is there any other
>> >>>> document or information related to OFDM modulator and demodulator
>> >>>> (Transceiver)? i haver to implement OFDM transmission and reception
>> via
>> >>>> USRP. i will really appriciate if you can help me that or someone
>> else
>> >>>> who knows how to implement by using GNU radio companion.
>> >>>> Thanks in advance.
>> >>>> Regards,
>> >>>> Waq.
>> >>>>
>> >>>>
>> >>>
>> >>>
>> >>
>> >>
>> >
>> >
>>
>>
>> -----
>> Sumit Kr.
>> Research Assistant
>> Communication Research center
>> IIIT Hyderabad
>> India
>> --
>> View this message in context:
>> http://old.nabble.com/OFDM-Implementation-tp32380874p32429184.html
>> Sent from the GnuRadio mailing list archive at Nabble.com.
>>
>>
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