A Signal Reacquisition Based on Cross-Entropy and Postdetection With Data Modulation for LEO Satellite Communications

Low Earth orbit (LEO) satellite communication systems are indispensable for next-generation communications, but face challenges in signal reacquisition due to data modulation under low signal-to-noise ratio (SNR) conditions. The existing algorithms either lack sufficient accuracy or involve excessively high complexity, presenting severe challenges for LEO satellite receivers. We propose a cross-entropy (CE)-based reacquisition algorithm, which addresses these challenges effectively by leveraging CE optimization to achieve rapid convergence and high detection probability. The proposed iterative architecture eliminates the exhaustive sequence search, significantly reducing computational complexity while maintaining high accuracy under low SNR conditions. Furthermore, theoretical analysis and numerical results are provided to demonstrate its superior performance compared to the existing algorithms. The study reveals a tradeoff between detection probability and computational efficiency, offering valuable insights for system optimization. These simulation results validate the proposed algorithm’s potential for practical deployment in LEO satellite communication systems.