The 2G-ALE System Based On 6748DSP And Its Modulation Recognition And Link Protection

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.