We put forth a project, that is: using the backscatter technique to realize adaptive long-distance HF broadcasting system in order to improve the quality of HF broadcasting. Then, we analyze errors of the system due t...We put forth a project, that is: using the backscatter technique to realize adaptive long-distance HF broadcasting system in order to improve the quality of HF broadcasting. Then, we analyze errors of the system due to the deviation of the ionospheric parameters' prediction. From the analysis, we draw the conclusion that our project is feasible. In addition, we point out that we can use frequency-spreading and information-coding technique to acquire more clear ionograms. We also offer a judgment on how to choose the control propagation mode on condition of multihop and the existence of more than one propagation mode on the signals' path.展开更多
We provide an efficient simulation tool for performance evaluation in communication networks. Not only the general simulation functions-which can be found in some old simulation tools, but also the perturbation functi...We provide an efficient simulation tool for performance evaluation in communication networks. Not only the general simulation functions-which can be found in some old simulation tools, but also the perturbation function module via the Standard Clock (SC) approach-in which more than 2 perturbation simulation event paths can be constructed parallelly based on a single nominal simulation event path is included in this simulation software platform.展开更多
To fit the autocorrelation functions (ACFs) of HF radar ionospheric backscattered signal to an analytical function, which is obtained theoretically by introducing a Lagrangian description of turbulent motion, can esti...To fit the autocorrelation functions (ACFs) of HF radar ionospheric backscattered signal to an analytical function, which is obtained theoretically by introducing a Lagrangian description of turbulent motion, can estimate directly the turbulent parameters of the scatters. We use this method to analyze the HF radar ACFs. A statistical study has been performed with the multi-frequency data, and shown that the statistical results are not the same in different frequency bands. We found that the influences of the limit radar time resolution and the received noise played the important roles in causing this inconsistency, both of them result in an additional expansion to the spectral width, and cause more Lorentzian behavior to ACFs; these two limitations affect the form of ACFs more seriously in the higher frequency band. We verified this by a simple simulation.展开更多
文摘We put forth a project, that is: using the backscatter technique to realize adaptive long-distance HF broadcasting system in order to improve the quality of HF broadcasting. Then, we analyze errors of the system due to the deviation of the ionospheric parameters' prediction. From the analysis, we draw the conclusion that our project is feasible. In addition, we point out that we can use frequency-spreading and information-coding technique to acquire more clear ionograms. We also offer a judgment on how to choose the control propagation mode on condition of multihop and the existence of more than one propagation mode on the signals' path.
文摘We provide an efficient simulation tool for performance evaluation in communication networks. Not only the general simulation functions-which can be found in some old simulation tools, but also the perturbation function module via the Standard Clock (SC) approach-in which more than 2 perturbation simulation event paths can be constructed parallelly based on a single nominal simulation event path is included in this simulation software platform.
文摘To fit the autocorrelation functions (ACFs) of HF radar ionospheric backscattered signal to an analytical function, which is obtained theoretically by introducing a Lagrangian description of turbulent motion, can estimate directly the turbulent parameters of the scatters. We use this method to analyze the HF radar ACFs. A statistical study has been performed with the multi-frequency data, and shown that the statistical results are not the same in different frequency bands. We found that the influences of the limit radar time resolution and the received noise played the important roles in causing this inconsistency, both of them result in an additional expansion to the spectral width, and cause more Lorentzian behavior to ACFs; these two limitations affect the form of ACFs more seriously in the higher frequency band. We verified this by a simple simulation.
