Researches On HF ALE Technology For Harsh Environments

Short-wave technology is a traditional communication method that can establish communication directly from point to point in the world without any relay system.It has the advantages of small size,flexibility,simple operation and firmness.However,the shortcomings of limited frequency resources and vulnerability to attenuation and interference have always restricted its development.In recent years,with the continuous breakthrough of computer technology,integrated circuits and other technologies,short-wave communication technology has been re-emphasized.Countries focus on using it as a military communication or civil emergency communication means to cope with the timely delivery of confidential information in different emergency conditions,so as to achieve the effect of "no bad,no disturbance",and have carried out a large number of researches.In this topic,my main job and innovations are as follows:(1)After analyzing the reasons why the short-wave communication system has been hampered,the accurate prediction of the short-wave sky-wave link is the premise of high-quality communication.In this thesis,before the short-wave communication simulation,the long-term channel prediction software VOACAP is used to obtain the channel quality parameters,and the short-wave mathematical channel model is combined to provide an accurate and high-quality pre-selected channel for establishing the link.(2)Referring to the existing automatic link establishment ALE technology of HF system,the paper studies the call channel scanning link establishment under scanning state,and then matches the service channel to complete the communication link establishment.The commnication mode is broadcasting and polling.Compared with the existing short-wave network topology,the advantages and disadvantages are balanced,and a new network topology that is more stable and reliable and easy to expand the node radio is selected to complete the automatic building.(3)This thesis establishes the 3G-ALE node model,related process model and network model by learning the use of OPNET Modeler14.5 simulation platform.The short-wave network automatic link establishment process and communication completion process of the designed short-wave network were simulated.The data link indicators such as the success rate of link establishment,network throughput and end-to-end delay are analyzed to verify the short-wave networking data link layer related protocols,which provides feasible support.