Patent ID: 8599901
Filing Date: 2013-12-03
Classification: H04B,H04K

Abstract:
1. A method for receiving a frequency hopping signal and estimating its parameters comprising: extracting discrete-time samples from the signal; creating a state-space vector sequence that captures an instantaneous frequency and a complex amplitude of the frequency hopping signal; selecting a parameter to represent the probability of hopping associated with the signal; generating a custom particle filter comprising an importance function with an associated weight updating scheme to approximate the posterior density of the instantaneous frequency and complex amplitude in the state-space vector sequence for succeeding time intervals using the extracted discrete-time signal samples up to a predetermined time; drawing random particles from the importance function for predetermined intervals of time using the associated weight updating scheme, the importance function having a closed-form mixture representation; using a mode of a local spectrogram to localize the frequency of new random particles drawn from the importance function, selecting new random particles around the peak frequency of the spectrogram for each interval of time, the importance function favoring drawing new particle frequencies biased close to the mode of the local spectrogram; applying weights derived from the associated weight updating scheme to the new random particles to create new weighted particle vectors; estimating the instantaneous frequency, and complex amplitude in the state-space vector sequence by averaging the instantaneous frequency and complex amplitude of the weighted particle vectors to thereby obtain an estimate of the instantaneous frequency and complex amplitude of the frequency hopping signal.