Why is SNR independent of the received signal power?

In SNR Definition Used in Link Simulations - MATLAB & Simulink - MathWorks 中国 SNR Verification for Frequency-Domain Channel Modeling.

In frequency-Domain

received signal is Y = Hx +n

By definition, SNR is the ratio of signal to noise, but the example given has no relationship between the noise and the received signal.

So with the same SNR, if the value inside the H matrix is small, doesn't this mean that the noise is even greater than x, resulting in a larger SNR again

Answer 1

[vidyesh]

Hi,

The nosie parameter n is inversely dependent on SNR value in the given example. Therefore for higer SNR, the noise values are smaller and realtively signal power is higer. Refer to the below section in the example where the "noise scaling factor" is generated. Therefore the received signal Y is dependent on SNR.

https://www.mathworks.com/help/5g/ug/snr-definition-used-in-link-simulations.html

Hope this helps