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Altera_Forum
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17 years ago

OFDM using DSP Builder

Hi, I'm trying to implement a simplistic (4 channel) QPSK OFDM transmitter/receiver using Altera's DSP Builder and Megacore IP in Simulink. Let me just mention that I have very basic knowl...
Altera_Forum's avatar
Altera_Forum
Icon for Honored Contributor rankHonored Contributor
17 years ago

Hi,

Thank you all for your replies.

*Correction about first post: I'm using the FFT block as an IFFT. As per OFDM design, the receiver contains an IFFT.

orchestradirector:

I don't understand what you mean when you say that I can transmit 1 and 0 values to the IFFT. In this case, where does the QPSK "constellation mapping" come in?

kaz:

I do I/Q mapping (QPSK). I mapped two bits into a symbol using QPSK. I and Q for each channel get the real and imaginary value. Based on my scenario, I have the following data after I/Q mapping:

Channel 1 I: +0.7071

Channel 1 Q: +0.7071

Channel 2 I: -0.7071

Channel 2 Q: -0.7071

Channel 3 I: +0.7071

Channel 3 Q: -0.7071

Channel 4 I: +0.7071

Channel 4 Q: +0.7071

My overall question is: Based on my scenario, how do I input the data into the IFFT (Altera FFT Block) and what would the data look like?