I am trying to use Matlab to simulate detection of signal, and the amplitude of signal is either 1 or 0. However, after the AWGN channel, I need to generate the white noise, and I know the variance of noise is proportional to the amplitude of signal for a given SNR. However, if my amplitude is 0, does that mean my variance of noise if 0? If that is true, then there will be no false alarm probability. If that is not true, then how do I calculate the variance of noise?
1 Answers
0
votes
The SNR is a ratio of the average power of the signal and the average power of the noise.
So in your example the signal is 0 and 1 and roughly half the time (if the data is independent and identically distributed, iid). Then the power would be:
0.5*0+0.5*1=0.5
so no the SNR is a ration between the 0.5 and the power of the noise.
Normally during the detection you would decide on a threshold, e.g. 0.5. If the detected signal is below the threshold you would decide on a 0 and if it is above you would decide on 1.
