Invention Grant
US09306718B2 System and method for mitigating helicopter rotor blockage of communications systems 有权
减轻通信系统直升机转子堵塞的系统和方法

System and method for mitigating helicopter rotor blockage of communications systems
Abstract:
A method for mitigating helicopter rotor blockage of communications comprising fast fourier transforming (FFT) pilot symbols, implementing a time delay of one frame, applying a forgetting factor to an accumulated spectrum, and performing a leaky coherent integration, wherein the leaky coherent integration adds a result of the fast fourier transform of the one current frame of data to the accumulated spectrum. The method also comprises calculating a threshold, wherein the threshold is based on a mean energy of all FFT bins in the accumulated spectrum, masking the FFT bins, wherein masking comprises retaining only FFT bins that exceed the threshold and above a minimum expected rotor blocking frequency, inverse fast fourier transforming the accumulated spectrum, erasing the pilot symbols below the threshold and removing them from the signal, and erasing data symbols that lie in a blockage by setting associated bit-log likelihood ratios to zero.
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