How can I add freq. offset(related to time index) after IFFT in data symbol in ofdm example?

GNU Radio
1

Hi guys,
Thanks in advance.

Since freq. offset is time related, like exp(2pi * f * t), how can I
generate freq. offset in gnuradio?
Normally, freq. offset exists due to mismatched oscillators between
transmitter and receiver.
Is that possible get the same freq. offset effect mentioned above,
merely
through modifying some code in GunRadio but not modifying the RF
hardware
in USRP. For example, if I want to add 1KHZ offset in sender in data
symbol(not preamble part,to avoid freq. offset correction), to see if
the
receiver can still succeed to decode the data, how should I do? Which
part
should I locate at after IFFT moving the samples to base band?

Thanks again.

Best,
Kay

2

Kay,

Freq offset can be added by multiplying the baseband data with
complex-exponential. In GR this can be done by any of the following ways

  1. Sine Source and Multiply block or
  2. Freq Translating FIR Filter
  3. Channel Model

-Adeel