Consider a discrete-time channel Y = X + Z, where the additive noise Z is signal-dependent. In particular, given the transmitted symbol X ∈ {−a, +a} at any instant, the noise sample Z is chosen independently from a Gaussian distribution with mean βX and unit variance. Assume a threshold detector with zero threshold at the receiver. When β = 0, the BER was found to be Q(a) = 1 × 10⁻⁸. (Q(v) = (1/√2π)∫_v^∞ e^−u2/2du, and for v > 1, use Q(v) ≈ e^−v2/2). When β = −0.3, the BER is closest to