SNR vs MCS rate for MM6108

General
1

Hello,

Does MM have any data available that shows the relationship between SNR and MCS rate for packet error rates of 1% or better? Asking as we would like to develop tooling that can better predict expected throughput for a given distance and noise floor. Thanks,

Alex

2

Hey @alexb

As the standard (IEEE80211-2024 23.3.18.1) specifies PER of 10%, the receiver sensitivities in our datasheet are for the same. See 5.5.2.1 https://www.morsemicro.com/resources/datasheets/chips/MM6108_Data_Sheet.pdf.

Your SNR to MCS rate can then be calculated

Thermal noise @ 25C: -174dBm/Hz
Noise power seen within BW of interest = thermal noise floor + 10*log10(BW in Hz)

So, its going to be :

  • -174 + [60, 63, 66, 69] = [-114, -111, -108, -105] for 1,2,4,8 MHz respectively
  • Assuming Noise figure of LNA is 4 dB
  • Effective Noise power = 4 + [-114, -111, -108, -105] = [-110, -107, -104, -101] dBm

You can then take the difference of the effective noise power to the sensitivity in 5.5.2.1 of our datasheet, to arrive at the SNR.
For example, if sensitivity of MCS0 on datasheet is -105 dBm for 1 MHz, then SNR = -105 - (-110) = 5 dB

MCS BW (MHz) SNR (dB)
0 1 5
1 1 8
2 1 11
3 1 14
4 1 17
5 1 21
6 1 22
7 1 23

Hope that helps.