# A New Improved Multi-Sequence Frequency-Hopping Communication Anti-Jamming System
## 2 Related Work
### Multi-Sequence Frequency Hopping  
References [25; 26; 27; 28; 29; 30] studied multi-sequence frequency hopping. Reference [25] proposed a multi-mode frequency hopping communication framework (MPFH), which was further enhanced through convolutional encoding and maximum-likelihood decoding. Based on the MPFH communication framework in [25], reference [26] proposed a wide-gapmulti-pattern frequency hopping communication method (WGMPFH) to resist reactive jamming, in which the transmitted signal induces reactive jamming to target the data channel, while the complementary channel uses a wide-interval frequency pattern to stay away from reactive jamming. Reference [27] proposed that the anti-jamming advantage of dual-sequence frequency hopping communication is applied to meet the anti-jamming requirements of space-tracking telemetry command receivers under a low signal-to-noise ratio. A multi-sequence frequency hopping communication framework (MSFH) represents messages through channels and has a strong anti-jamming ability. Compared with differential frequency hopping (DFH), it has a better anti-jamming effect in the face of partial frequency band jamming [28]. Reference [29] mentions that DFH has good anti-tracking jamming performance, but it points out that the DFH receiver does not have prior knowledge of channel selection and generally adopts broadband reception for the entire operating frequency band. Broadband reception brings problems such as high hardware overhead and difficult networking. Without considering coding, its performance is not as good as conventional frequency hopping when facing non-tracking jamming such as sweep jamming and multi-tone jamming. Compared with DFH, MSFH can adopt narrowband reception, which has a better anti-jamming effect when facing complex jamming [30]. In order to maximize coding gain, narrowband filtering is generally not performed. In a complex jamming environment, there is not only reactive jamming, but there are also other types of random non-intelligent jamming, such as multi-tone jamming and sweep frequency jamming. Although there have been some research achievements in using anti-jamming methods to deal with certain fast and complex reactive jamming [19], in complex jamming environments, the error rate increases, which affects the anti-jamming performance. Studying the performance of MSFH in complex jamming environments is of great significance for evaluating its emergency communication performance. This paper proposes an intelligent multi-sequence frequency hopping communication framework that effectively addresses jamming in complex jamming environments by utilizing reactive jamming. Although some studies have improved the anti-jamming performance of multi-sequence frequency hopping, they have only actively avoided reactive jamming and have not changed its passive anti-jamming nature. For example, reference [25] only analyzed the system performance of multi-sequence frequency hopping communication systems under reactive jamming, without pointing out ways to deal with reactive jamming. Reference [26] only use a wide-interval frequency mode to keep complementary channels away from reactive jamming. Inspired by the idea of jamming utilization in [19], in order to make the jamming utilization method universal, improve the efficiency of reactive jamming utilization, and enhance the anti-britteness of communication systems, more in-depth research is needed for existing analysis models [25] that ignore the impact of environmental noise on the system. This article proposes an intelligent multi-sequence frequency hopping communication framework that effectively improves communication performance by utilizing reactive jamming. Frequency hopping (MSFH) represents messages through channels and has strong resistance to tracking jamming. Compared with differential frequency hopping (DFH), it has a better anti-jamming effect in the face of partial frequency band jamming.