Additive white Gaussian noise (AWGN) is a basic noise model used in information theory to mimic the effect of many random processes that occur in nature. The modifiers denote specific characteristics: * Additive because it is added to any noise that might be intrinsic to the information system. * White refers to the idea that it has uniform power across the frequency band for the information system. It is an analogy to the color white which has uniform emissions at all frequencies in the visible spectrum. * Gaussian because it has a normal distribution in the time domain with an average time domain value of zero.