Why mean is zero in awgn channel?

In an Additive White Gaussian Noise (AWGN) channel, the noise is characterized by a Gaussian distribution with a mean of zero. This means that, on average, the noise does not introduce a bias to the transmitted signal; it can be positive or negative, equally likely. This property ensures that the expected value of the noise over time is zero, allowing for accurate signal recovery and reliable communication. Consequently, the signal's integrity is maintained as the noise essentially fluctuates around zero.