【作者】 徐亮；

【导师】 杜栓义；

【作者基本信息】 西安电子科技大学 ， 通信与信息系统， 2015， 硕士

【摘要】 短波通信作为无线通信领域中的一种重要通信方式,一直是人们探索研究的热点。由于短波通信使用的主要传输信道为天波,该信道属于变参信道,具有时变特性,所以研究自动链路建立技术来检测当前时刻信道质量,并选择最优信道建立链接成为必然选择。2G-ALE技术作为最早被广泛使用的自动链路建立技术,具有重要的应用价值。首先基于双DSP+FPGA设计搭建了硬件平台,并根据美军标MIL-STD-188-141A的要求,在6748DSP上完成了2G-ALE的单呼、探测、扫描、网呼等基本功能。系统可以通过上位机的控制完成对通信双方信道质量的探测,并在选择最优信道之后完成链路建立。然后根据2G-ALE系统需要发前听的需求对调制识别技术进行了研究,参考已有的调制方式识别算法,给出了一种能够识别2ASK、2PSK、4PSK、8PSK、2FSK、4FSK、8FSK和噪声的识别算法,并仿真了该算法的性能。之后重点研究了应用于2G-ALE系统中发前听的8FSK信号识别算法,并介绍了该算法在2G-ALE系统中的实现。最后针对2G-ALE的信令容易受到外界的恶意侦听与干扰的问题,设计实现了2G-ALE系统的链路保护。论文对所设计实现的功能进行了测试验证。更多还原

【Abstract】 As an important way in wireless communication field, HF communication has been a hot research exploring. Since HF communication’s main transmission channel is sky wave,which belongs to the varying parameter channel, the research about Automatic Link Establishment technology has been an inevitable choice. ALE is used as link quality analysis in real time, the best channel selection and link setup. As the first to be widely used in ALE system, 2G-ALE is of an important application value.Firstly, an universal hardware platform with double DSP and FPGA is designed in this thesis. According to the requirement of US military standard MIL-STD-188-141 A, the basic functions about 2G-ALE are completed on 6748 DSP, such as individual calling,sounding, scanning and network calling. The link quality analysis, the best link selection and link setup are realized in this thesis. Then, according to the demand of monitor before link establishment in the 2G-ALE system, modulation recognition technology is studied.Referencing conventional modulation recognition algorithm, a new recognition algorithm to recognize 2ASK, 2PSK, 4PSK, 8PSK, 2FSK, 4FSK, 8FSK and noise is analyzed and simulated. Then the 8FSK signal recognition algorithm is discussed, and this 8FSK modulation signal is used in 2G-ALE system. Finally, considering the 2G-ALE signaling being easy to be monitored and malicious interference, Link Protection section is designed in the 2G-ALE system. All of the functions are tested and verified.更多还原