How to generate LTE15 PRACH subframes?

Hi experts,

I am trying generate LTE15 (NULRB = 75) PRACH format 0 subframes. The expected subframe length is 23040 samples but ltePRACH() yields subframes of length 30720.

Is there anyway to get the correct subframe length from the LTE Toolbox without custom code for resampling?

Thank you very much.

Answer 1

[Iain Stirling]

Hello Reza,

It is not possible to directly generate the waveform at a different sampling rate, but it should be very easy to perform resampling using the MATLAB resample() function as follows:

>> ue.NULRB = 75;
>> prach.Format = 0;
>> waveform = ltePRACH(ue,prach);
>> waveform = resample(waveform,23040,30720);
>> size(waveform)

ans =

       23040           1

For information, the reason we use 30.72 Ms/s is for compatibility with our normal uplink waveforms created using lteSCFDMAModulate.

Regards,

Iain.