Adaptive Multistate Markov Channel Modeling Method for Reentry Dynamic Plasma Sheaths
Channel modeling of a plasma sheath for hypersonic reentry vehicles is important in addressing reentry communication blackout issues. Given that the time-varying property of the transmission medium is caused by physical factors such as large-scale flight conditions variation, especially angle of attack, and small-scale fluid turbulence, a new adaptive multistate Markov channel modeling method is proposed to present the dynamic effects of reentry plasma sheaths on wireless channels. First, a quasi-Gaussian function mathematical model for the electron density of a dynamic plasma sheath is established according to the variation frequency of the dynamic physical factors. Then, the time-varying attenuation is calculated by combining the quasi-static Monte Carlo and uniform hierarchical analytical methods for nonuniform electronic density distribution. Finally, a hidden Markov model is employed to model the channel characteristics of the dynamic plasma sheath, and a reversible-jump Markov chain Monte Carlo algorithm is used to adaptively estimate the channel parameters of the multistate Markov channel. Simulation results show that the first-order statistical properties of the proposed channel are in good agreement with the calculated variable attenuation of radio waves, and this method has the adaptive capacity to estimate the number of multiple states and the channel parameters in each state without a need for manual setting.