At \( t_0 \), solve \( \theta_A(t) = \alpha(t) \) and \( \phi_A(t) = \delta(t) \) to optimize \( L_b = EIRP - 20\log_{10}(d) + G_R - L_p \), ensuring \( \text{SNR} \geq \frac{P_s}{N_0} \) and \( BER \leq 10^{-9} \) under \( \Delta f \).