【作者】 李强；

【导师】 朱晓明；

【作者基本信息】 西安电子科技大学 ， 通信与信息系统， 2022， 硕士

【摘要】 短波通信凭借其自身特有的优势成为现代通信不可或缺的重要通信方式。在双方的通信中,如何建立高效、稳定的通信链路一直是短波通信的难点。本文介绍了MILSTD-188-141D的WALE波形中的Deep WALE,探讨了宽带自动建链技术,设计了根据不同需求发送的特定PDU。此外,信号在信道中传输经历的各种衰落在接收端会产生非常大的影响,故如何对抗衰落一直是短波通信的重点。针对这种情况,分集合并技术是一种有效的方法。本文对分集合并技术做了简单介绍,并在原四路接收合并处理系统的基础上成功改进成八路接收合并处理系统。八路接收合并处理系统采用的是自适应技术,表现为发送端在八个频点上进行建链尝试,接收端则选择最优的频点进行链接,即频率选择采用的是WALE波形中的多频点检测技术。首先对建链系统与分集合并系统用到的硬件平台——DSP+FPGA平台进行了介绍,并就有关模块进行了详细说明,根据相关要求给出了具体配置。接着详细介绍了Deep WALE波形,并根据波形的特点设计了可根据指定功能发送的特定PDU,包括建链PDU,确认PDU,拆链PDU等。这些不同协议数据单元可以实现信道评估、选择性呼叫、流量协商、数据和文本消息的传递等功能。另外,还对Deep WALE在MATLAB系统中进行了仿真,给出了仿真测试结果,结果表明达到了美军标的要求。然后讨论了时间分集、空间分集、频率分集三种分集合并方式,并给出了发送端的相关技术,如编码、交织、调制和加扰等。同样也给出了接收端的同步捕获、频偏估计等技术。分析讨论了选择式合并、等增益合并、最大比值合并的优劣,并在MATLAB系统中进行了仿真比较,八路接收合并处理系统选择了性能最优的最大比值合并方式。最后,对改进的八路接收合并处理系统进行了测试,测试结果达到了设计要求。更多还原

【Abstract】 HF communication has become an indispensable way of modern communication with its own unique advantages.In the communication between the two sides,how to establish efficient and stable communication link is always the difficulty of HF communication.In this thesis,Deep WALE waveform in MIL-STD-188-141 D WALE waveforms is introduced,and wideband automatic link establishing technology is discussed.Moreover,the specific PDUs are designed according to different requirements.In addition,the signals through HF channel will be faded,so how to fight with the fading has been the focus of HF communication.Aiming at this situation,an effective method is the diversity merging which is introduced in this thesis.Also,the eight channels receive combining system is successfully studied based on the original four channels receive combining system.An adaptive technology is adopted to the system,which means that the transmitter attempts to establish a link on eight frequency points,and the receiver selects the optimal frequency point for linking,that is,the multi-frequency detection technology in the Deep WALE waveform is applied to the frequency selection in the eight channels receive combining system.Firstly,the hardware platform about DSP+FPGA is introduced,the key modules used for the automatic link establishment system and diversity merging system are illustrated in this thesis.Meanwhile,the specific configuration is given according to the relevant requirements.Then,Deep WALE waveform is introduced in detail.And specific PDU is designed for specific functions according to the characteristics of waveforms,including link establishment,termination,confirmation,etc.These different protocol data units are used for channel evaluation,selective call,traffic negotiation,data and text message transmission and other functions.In addition,Deep WALE waveform is simulated and tested in MATLAB.The results meet the requirements of US military standard.Next,the diversity merging technique is discussed.The diversity merging technologies about time diversity,space diversity and frequency diversity are briefly introduced,and the related technologies used for the transmitter are given,such as encoding,interleaving,modulation,scrambling,etc.The techniques of synchronous capture and frequency offset estimation used for the receiver are also presented.The advantages and disadvantages of selective merging,equal gain merging and maximum ratio merging are analyzed and discussed,and the simulation comparison is carried out in MATLAB.By comparison,the maximum ratio merging is selected by the eight channels receive combining system.Finally,the eight channels receive combining system is tested on the hardware platform.The test results show that it meets the design requirements.更多还原