Code-Aware Anti-Jamming Method for FHSS Systems: Leveraging Diversity Combination

Frequency hopping spread spectrum (FHSS) systems exhibit exceptional resilience against jamming through the utilization of time-frequency diversities, which, when coupled with near-Shannon limit channel codes, yield favorable performance outcomes. The coherently combined and decoded signals at the receiver effectively eliminate the impact of partial-band jamming. This letter proposes a novel low complexity low-density parity-check (LDPC) code-aware diversity combining anti-jamming (LCA-DCAJ) method for fast frequency hopping (FFH) systems. Our approach seamlessly integrates multidimensional (time-frequency) diversities, FFH strategies, and LDPC coding techniques, resulting in outstanding suppression of interference within the time-frequency domain. Addressing concerns over complexity, we propose a triple log-likelihood ratio (LLR) threshold detection algorithm to further streamline implementation procedures. Bit error rate (BER) and average processing delay (APD) analyses underscore the superiority of the proposed anti-jamming method, validating its effectiveness in practical scenarios.