GA-Driven Joint Estimation of Time-Hopping Patterns and Carrier Parameters in Secure LEO Communications
摘要
Low Earth Orbit (LEO) satellite systems serve as critical infrastructure for internet of things (IoT), military, and emergency missions due to their low-latency global coverage. This work leverages time-hopping (TH) technology’s interference resilience and low-probability-of-intercept characteristics through a TH communication architecture where signals are distributed across pseudo-random TH sequences. The receiver implements joint de-hopping and carrier offset synchronization to enable multi-hop coherent combining for signal-to-noise ratio (SNR) enhancement in low- \(E_\textrm{b}/N_\textrm{0}\) regimes. To overcome TH pattern randomness and dynamic frequency-phase distortions, we develop a genetic algorithm (GA)-driven hierarchical estimation framework comprising coarse and fine synchronization stages. Application-specific genotype encoding and dedicated crossover mechanisms, guided by a signal-energy fitness metric, ensure rapid convergence to global optima. Numerical simulations demonstrate that the proposed architecture achieves near-theoretical bit error rate (BER) performance with \(5.61 \times 10^{-5}\) symbol-rate-normalized frequency root mean square error (RMSE) and 0.044 rad phase RMSE at 4 dB per-hop \(E_\textrm{b}/N_\textrm{0}\) , outperforming conventional single-stage estimation strategies in precision and robustness.