无线通信传播介质共享开放的特性，使其更容易受到干扰。而跳频通信作为一种扩频通信方式，因其强大的抗干扰能力和良好的扩展性，在无线通信系统中有着重要的应用。但是，随着移动设备的急剧增加，对频谱资源的使用变得更加复杂，这对跳频通信系统的抗干扰能力和同步性能提出了更高的要求。因此，如何在复杂电磁环境下将性能更优的跳频序列和同步方案应用于跳频通信系统中具有重要的研究意义。本文主要工作如下：

为了使跳频通信系统在复杂干扰的环境中仍能维持稳定的通信效果，本文提出一种基于灰狼算法的跳频序列设计方法。首先以复杂电磁环境为背景，对跳频序列设计方法进行数学建模，将其核心问题转化为单目标优化问题进行处理。其次考虑到计算复杂度，本文选用灰狼算法对优化问题进行求解，为进一步提升算法的收敛速度，通过引入Sin混沌映射和新型反向学习策略、优化线性变化的收敛因子以及增加非均匀变异算子进行局部扰动的方法，对灰狼算法进行改进。最后将改进后的灰狼算法用于求解最优跳频序列，生成跳频图案。仿真实验结果表明，在标准测试函数方面，本文提出的改进灰狼算法收敛速度比传统灰狼算法提升一倍左右，较其他优化算法在解决局部最优问题时表现更突出；在复杂干扰的环境中，相较于传统跳频序列，本文设计的跳频序列的最大汉明自相关值较小且被干扰概率降低约30%。这表明，使用本文方法设计的跳频序列能有效应对复杂的电磁干扰环境，为无线通信系统的稳定性和可靠性提供了有力的支持。

为了解决长周期序列同步困难的问题，本文提出一种时间信息与单通道慢速扫描相结合的同步方法。该方法利用时间信息的高位信息映射序列相位，并将时间信息和序列的初始相位联系在一起，通过单通道慢速扫描的方式来捕获接收信号，从而在确保捕获效率的同时，尽可能降低硬件复杂度。同时，本文针对该同步方法对跳频系统进行整体建模并设计相应的帧格式；采用PMF-FFT同步捕获算法作为二维捕获的实现算法，并对其判决门限进行改进，提升了系统的捕获性能；在传统的早迟门跟踪方法的基础上进行改进，从而缩小误差波动范围。

对跳频系统同步性能进行测试与分析。测试结果显示，本文所设计的跳频通信系统在信噪比为-12 dB的恶劣环境中，依然可以稳定的完成同步，并且同步捕获概率可达到99.6%；此外，同步建立时间小于10.8 ms，即便在通信过程中发生了失步情况，系统也能迅速恢复，重新建立捕获的时间控制在8秒以内。以上实验结果都充分证明了本文设计的跳频通信系统在复杂电磁环境中的可行性以及性能的优越性。

The characteristic of sharing openness of wireless communication propagation medium makes it more susceptible to interference. And frequency hopping communication, as a spread spectrum communication method, has an important application in wireless communication system because of its strong anti-interference ability and good scalability. However, with the dramatic increase of mobile devices, the use of spectrum resources has become more complex, which puts higher requirements on the anti-interference ability and synchronisation performance of frequency hopping communication systems. Therefore, it is of great research significance to find out how to apply frequency hopping sequences and synchronisation schemes with better performance to frequency hopping communication systems in complex electromagnetic environments. The main work of this dissertation is as follows:

In order to make the frequency hopping communication system maintain stable communication effect in the environment of complex interference, this dissertation proposes a frequency hopping sequence design method based on grey wolf algorithm. Firstly, taking the complex electromagnetic environment as the background, mathematical modelling is carried out for the frequency hopping sequence design method, and the core problem is transformed into a single-objective optimization problem for processing. Secondly, considering the computational complexity, the grey wolf algorithm is chosen to solve the optimization problem. In order to further improve the convergence speed of the algorithm, the grey wolf algorithm is improved by introducing Sin chaotic mapping and a new type of inverse learning strategy, optimizing the convergence factor of the linear variation, and adding non-uniform variation operator for local perturbation. Finally, the improved grey wolf algorithm is used to solve the optimal frequency hopping sequence and generate frequency hopping patterns. Simulation experimental results show that, in terms of the standard test function, the convergence speed of the improved grey wolf algorithm proposed in this dissertation is about double than that of the traditional grey wolf algorithm, and its performance is more outstanding than that of other optimization algorithms in solving the local optimal problem; in the environment of complex interference, compared with the traditional frequency hopping sequences, the maximum Hamming autocorrelation value of the frequency hopping sequences designed in this dissertation is smaller and the probability of being interfered with is reduced by about 30%. This shows that the frequency hopping sequence designed using the method in this dissertation can effectively cope with the complex electromagnetic interference environment, which provides a strong support for the stability and reliability of the wireless communication system.

In order to solve the problem of difficult synchronisation of long-period sequences, this dissertation proposes a synchronisation method that combines time information with single-channel slow scanning. The method makes use of the high level information of the time information to map the sequence phase, and associates the time information with the initial phase of the sequence, and captures the received signals by means of single-channel slow scanning, so as to reduce the hardware complexity as much as possible while ensuring the capturing efficiency. At the same time, this dissertation models the frequency hopping system as a whole and designs the corresponding frame format for this synchronisation method; adopts the PMF-FFT synchronous capture algorithm as the implementation algorithm for two-dimensional capture, and improves its judgement threshold, which enhances the capture performance of the system; and improves the traditional early-late gate tracking method on the basis of the traditional early-late gate tracking method, so as to reduce the range of the error fluctuation.

The synchronisation performance of the frequency hopping system is tested and analysed. The test results show that the frequency hopping communication system designed in this dissertation can still complete the synchronisation stably in the harsh environment with a signal-to-noise ratio of -12dB, and the probability of synchronous capture can reach 99.6%; in addition, the synchronisation establishment time is less than 10.8ms, and even if the out-of-step situation occurs during the communication process, the system can recover quickly, and the re-establishment of capture time is controlled to be less than 8s. The above experimental results fully prove the feasibility and superiority of the frequency hopping communication system designed in this dissertation in the complex electromagnetic environment.