Hf Channel Modeling And Simulation Technology Research

Radio channel characterisation is an essential element in the design and testing of any communication system. As for HF ionospheric channel, because of the great variation of ionosphere with different times and locations, it is more difficult to adequately test out new HF communication systems. Thus, due to its advantages of accuracy, repeatability and low cost, HF channel simulation has been commonly recognized as an effective mean for the evaluation of HF system performance.Currently, the most widely accepted HF channel model is only valid for narrow bandwidth. However, when dealing with wide band systems up to 1 MHz in bandwidth, the dispersion characteristics of the ionospheric conditions must be modelled in a way that allows complete representation of their effect across the whole bandwidth dynamically. This dissertation presents a modified wideband HF (WBHF) channel model and architecture for the implementation of this model.Central to the wideband simulation is the description of the delay power profile (DPP) of each propagation mode or path. ITS WBHF channel model has provided a form of DPP, while it's too complex for implementation. Given the difficulties of specifying and implementing the proposed delay profile, a properly modified DPP is presented in this dissertation, which has a close-form expression and a similar statistical characteristic with ITS model.Based on the theory channel model, an architecture for simulation implementation is further studied, the algorithm for determination of the parameters in this newly presented implementation model is also discussed.The generation of multiple uncorrelated coloured Gaussian random processes is demanded for simulating wideband HF channel, In this dissertation, an improved deterministic sum-of-sinusoids (SoS) channel simulator with a new parameter computation method is proposed to simulate a large number of uncorrelated coloured Gaussian random processes. Compared with the existing SoS channel simulators, the proposed deterministic SoS model yields a much better simulation efficiency and while still preserving satisfactory approximations to the desired statistical properties of the reference model.Finally, HF aeronautical channel characterisation is discussed. The HF Air-Air and Air-Ground aeronautical channel model are presented respectively.