How may samples per symbol in ieee 802.11 g I am doing a baseband simulation for IEEE 802.11 g. The standard uses 64 IFFT length ($3.2 \mu s$) and 20 Msamples per second. This result in one sample per symbol. I am wondering what the structure will be if I use 40 Msample per second, i.e will the IFFT size change, or interpolation will be used?

Thanks
If you oversample the signal by a factor of 2 as you've suggested, then you will have a bunch of empty subcarriers that are outside the specified signal bandwidth. When you modulate the OFDM frame to a time-domain signal, therefore, you'll have to use an IFFT that is twice as long. The result will be a discrete-time signal that is interpolated by a factor of 2 compared to using the nominal sample rate.