Support for different sample rates

[danielschaeufele]

In a practical system the signal is usually upsampled before transmission (mainly to not violate the spectral emission mask). E.g., a signal with 100MHz bandwidth is usually transmitted with 122.88MHz sample rate.

Implementing this as a separate step is not terribly difficult (all that is needed is a larger FFT size and CP length with zero padding/removal), but it would be much more convenient to have support for this in PUSCHTransmitter/PUSCHReceiver. I could contribute an implementation if there is interest from the sionna team.

[jhoydis]

Hi @danielschaeufele,

That sounds probably like a nice feature. It would be desirable to have this available not only for the NR module but as a general block, maybe as an add-on for the OFDM modulation, demodulation blocks.
Alternatively, we could consider a resample block that would process time-domain signals.

[danielschaeufele]

I think the support is basically already there, it just needs to be enabled for PUSCHTransmitter/PUSCHReceiver. All that needs to change, would be to increase the FFT size and CP length for the OFDMModulator/OFDMDemodulator and then add the appropriate number of guard carriers in the ResourceGrid.

I hope I can prepare some code next week.