Re: [Discuss-gnuradio] OFDM Implementation

[sumitstop]

Hi,
sorry my internet was down for almost 12 hrs... so whts the situation
now.are you able to transmit and receive .... 
 

waqasme wrote:
> 
> Hi Sumit,
> Thanks you so much for ur detailed explanation . i really appriciate your
> help.
> I am following the same steps as you mentioned earlier but iam getiing
> this message when i am entering these comands in terminal. here is the
> messages .
> 
> address@hidden:~$ /usr/local/bin
> bash: /usr/local/bin: is a directory
> address@hidden:~$ directory/usr/local/bin
> bash: directory/usr/local/bin: No such file or directory
> address@hidden:~$ /usr/local/bin
> bash: /usr/local/bin: is a directory
> address@hidden:~$ benchmark_ofdm_tx.py-h
> benchmark_ofdm_tx.py-h: command not found
> 
> when i enter this comand i get this result
> address@hidden:~$ directory/usr/local/bin
> bash: directory/usr/local/bin: No such file or directory
> address@hidden:~$
> No such file or directory.  how to access that directory? do i need to run
> some other commands before that ? 
> what could be the problem ? any suggestion ?
> 
> 
> sumitstop wrote:
>> 
>> go to the directory /usr/local/bin
>> there u will find benchmark files for ofdm (both transmission and
>> reception)
>> u need to type benchmark_ofdm_rx.py -h
>> and benchmark_ofdm_tx.py -h
>> 
>> these will show you the parameters u can play with.
>> 
>> after that u can run these files by typing ./benchmark_ofdm_tx.py -f
>> <frequency appropriate to ur daughter board>
>> and ./benchmark_ofdm_rx.py -f <frequency appropriate to ur daughter
>> board>
>> 
>> also there may be drift in the center frequency of the daughter board so
>> u can do one thing. first run the transmitter part and see on the
>> spectrum analyzer for the center frequency of the ofdm signal.
>> 
>> after that run the receiver part with that center frequency specified in
>> the arguments.
>> now run the transmitter again with the same frequency.
>> 
>> if u get timeouts then u need to play with the receiver gain and
>> transmitter amplitude as well as the receiver center frequency.
>> 
>> u can change the bandwidth of the ofdm signal by changing the no of
>> occupied tones or fft length because bw = occupied tones/ fft length
>> 
>> let me know ur results.
>> 
>> Regards
>> 
>> waqasme wrote:
>>> 
>>> hello sumit,
>>> yah i have replaced the GMSK modulator and demodulator with OFDM
>>> modulator and demaodulator. but i coudlnot find message source ,
>>> ,message sink, probe signal and probe avg mag 2 with only input .. the
>>> one i have found has input and output as well for probe avg mag 2
>>> block... i couldnot able to find these blocks as in the simple
>>> tranceiver diagram example they used these blocks... can you plesase
>>> guide me where to get these blocks? 
>>> Also you mentioned this command ( benchmark_ofdm.py -h )   is that a
>>> command or what? because i have entered this command in terminal window
>>> but it says command not found? and if i type in google to search it
>>> opens a c ++ code ..what i am suppose to do with that. ?? please tell me
>>> how to use this benchmark_ofdm.py code.. where to put this code to make
>>> the simulation work. i am very new to GNU radio so i have no idea what
>>> functions i can play with and how to implement this. please guide me 
>>> like how to make this OFDM tranmission and reception  via USRP.  iam
>>> using Linux Ubuntu maveric and GNU Radio companion 3.2.2 version... I
>>> really appriciate your help because i have only few time left for my
>>> Masters project. Thanks in advance i am looking forward to hear from
>>> you.
>>> 
>>> Regards,
>>> Waq.
>>> 
>>> sumitstop 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
-- 
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