Baseband vs Passband simulation in terms of noise impact
In fact, bandpass noise (or any kind of noise process) can be modelled as a system $h(t)$. As so, there is a lowpass equivalent $h_l(t)$ such that

\begin{equation}
h(t) = Re[h_l(t)\exp(j2\pi f_0t)]
\end{equation}

So you can work with $h_l(t)$ in the baseband.