Hi Kavyashree,
I understand your issue, when you make perfectChannelEstimate as “false” in the NPUSCH BLER example, the results appear incorrect, and you would like to know what is happening in the background when perfectChannelEstimate = false.
When perfectChannelEstimate = false, the simulation no longer uses the ideal channel response. Instead, it calls the practical estimator lteULChannelEstimateNPUSCH, which performs:
- Channel estimation (hEst) using the NPUSCH Demodulation Reference Signal (DRS).
- Noise power estimation (noiseEst) by averaging least-squares estimates of the DRS across time and frequency.
In cases like very small allocations e.g., 1 RU, 1 subcarrier, SCS = 3.75 kHz, the number of DRS symbols is very limited. If the estimator cannot extract or average enough valid pilots, noiseEst can become zero or very small.
Helpful documentation links:
https://www.mathworks.com/help/releases/R2023b/lte/ug/nb-iot-npusch-block-error-rate-simulation.html
Hope this helps.
