RE: [Discuss-gnuradio] Benchmark_ofdm_tx Benchmark_ofdm_rx

[matteo zunino]

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> Date: Tue, 1 Jul 2008 08:44:37 -0700
> From: address@hidden
> To: address@hidden
> CC: address@hidden
> Subject: Re: [Discuss-gnuradio] Benchmark_ofdm_tx Benchmark_ofdm_rx
>
> On Tue, Jul 01, 2008 at 05:17:06PM +0200, matteo zunino wrote:
>>
>>>>>> Hi,
>>>>>>
>>>>>> i've a question about these two functions. My aim is to modify these
>>>>>> benchmarks in order to create a trasmission system that can choose
>>>>>> to put on a single carrier a BPSK or a QPSK modulation. My problem
>>>>>> is this one, how can i comunicate to the receiver what carriers are
>>>>>> BPSk adn what QPSK?
>>>>>>
>>>>>> Thanks a lot
>>>>>
>>>>> This is typically done by sending some kind of 'map' at the low rate
>>>>> at the beginning of packet.  Take a look at WiMAX to see how
>>>>> complicated this can get ;)
>>>>>
>>>>> Eric
>>>
>>>> I've seen it ;) but i've problem too even if i konw what carriers
>>>> are BPSK and what are QPSK. I've studied how to modify ofdm.py in
>>>> order to transmitt for example the first 10 signals with BPSK
>>>> modulation and tre other with QPSK, but when i want to demodulate, i
>>>> don't know which point of gr_ofdm_frame_sink.cc i must modify to
>>>> demodulate correctly. Do you think my project is possible actually
>>>> in gnuradio OFDM?
>>>
>>> Sure it's possible.  You'll have to do some work.
>
>
>> Excuse me for the continue questions but i've not such a big
>> experience in Gnuradio. Where i i would modify gr_ofdm_frame_sink.cc
>> in order to arrive to my aim? I don't know c++ language very well
>> and i don't know where i can find it in this function
>>
>>  Thanks a lot
>>
>> Matteo
>
> Matteo, I haven't looked at this code in a while and don't plan to at
> this time.  I'm working on other pieces of GNU Radio right now.
>
> You asked me if it's possible, and I said yes.  It will take some
> study and some work.  Perhaps this is an opportunity to improve your
> programming skills?  You may have to look beyond gr_ofdm_frame_sink.cc
> and understand how the whole OFDM system is put together.
>
> Each piece and feature of GNU Radio got written because somebody cared
> about that part.  We all started out knowing nothing.  You appear to
> be the person that cares about doing different modulations on
> different subcarriers.  You know what you want.  You know a little bit
> about the current code.  You're exactly where you're supposed to be to
> get started on it...
>
> Good luck!
> Eric

Sorry, i don't want to look at this function but only know if you have already 
look at it ;)
however, Thanks a lot for all the informations you give me.
Hi, sorry again for the disturbe.

Matteo

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