Re: GNURadio OFDM multiple data in subcarriers.

Hi Sourya,

before embarking on that endeavour: Have you made sure you can transmit a single file on
all subcarriers?

Best,
Marcus

On 18.03.24 18:15, Sourya Saha wrote:
> Hi all,
> I was trying to send contents of a file using a single subcarrier in OFDM. As Marcus
> pointed out, it is a complex process and i found out that using a single data carrier
> for the main data apart from the carriers for the header and sync words, the channel
> estimation takes forever. The data is never decoded.
>
> What I want to do is use different subcarriers of the OFDM transmitter to send different
> file contents. Say use subcarrier 3, 4 to send contents of file 1 and subcarriers 7, 8
> to send contents of file 2. I want to do it simultaneously. I am using USRP B200 on
> both. I tried using 2 flowgraphs, one for each file, in the same grc file for doing it.
> The transmitter seems to send the required data. I tried decoding it with the loopback
> flowgraph. The output was redirected to the terminal. The contents were being printed
> properly.  But whenever I use the USRP, the receiver side just stops working. The
> receiver side also has 2 flowgraphs running with the corresponding values of the
> subcarriers.
>
> For ofdm transmitter 1, the parameter values are:
> Occupied carriers- ((-2, -1, 2, 1 3, 4),)
> Pilot carriers- ((-21, -11, 11, 21),)
> Pilot symbols- ((-1, 1, -1, 1),)
>
>
> For ofdm transmitter 2, the parameter values are:
> Occupied carriers- ((-4, -3, -5, -6, 6, 7),)
> Pilot carriers- ((-26, -25, 26, 25),)
> Pilot symbols- ((-1, 1, -1, 1),)
>
> I want to do it using a single flowgraph. What would be the right way to proceed with this?
>
>