The given stochastic $y[n]$ is composed of two signals, $s[n]$ which is the desired signal, and $\epsilon[n]$ is the noise which is a zero-mean weak-sense stationary signal. The desired signal is a sinusoid function with unknown amplitude and the initial phase is also a stochastic variable distributed according to a rectangular pdf with support $[0, 2\pi)$.
$$y[n] = s[n] + \epsilon[n]$$
I try to compute the FFT of $y[n]$ to see what the signal looks like in the frequency domain but it doesn't help much. So my thought is to find cross-correlation and then effect spectrum. In order to find the bandstop frequency.
Can someone guide me on how to solve this kind of problem?