Research On Fixed-frequency Inhibition Of Frequency-hopping Using Compressive Sampling

Since the frequency hopping technology was invented, it has been widely used in militarycommunications because of the advantages of anti-jamming, low probability, high spectralefficiency and so on. Howerver, the frequency hopping bandwidth becomes wider and wider.Because of the limitation of the Nyquist sampling theory, we have encountered many difficulties onaccount of the level of existing hardware technology in the applications of ultra high frequencyhopping communication system.The compressive sampling theory appeared these years breaks through the limitation of theNyquist sampling theory. The compressive sampling theory points out that we can efficientlysample signals by using few of the incoherence measurements with low speed if the signals aresparse in some transform domain. Corresponding to the difficulties encountered in the ultrawideband frequency hopping signal detection recently, we do research into the AIC technology offrequency hopping using compressive sampling when we apply compressive sampling to thefrequency hopping signal acquisition. However, the large wideband of the frequency hoppingsignals will definitely lead to the mix of numerous of fixed-frequency interference signals, whichincrease the sparsity of the frequency hopping signal and influence the efficiency of thecompressive sampling of frequency hopping signal. In order to solve the hardware and algorithmproblems caused by the direct compressive sampling which obeys the rule“Reconstruction first,then inhibition”, we proposed three fixed-frequency inhibition methods which obey the rule“Inhibition first, then reconstruction”. The first one is posteriori compressive sampling. The secondone is annihilation filter. The third one is the method of using minimum mean square error. Andaccording to these three methods of fixed-frequency inhibition, we constructed a model based thesimplified measurement matrix of the compressive sampling of frequency hopping signal, whichgave us a new idea to solve the acquisition of ultra wideband frequency hopping signal.There are four main parts in this paper. The first part introduces the basic principles offrequency hopping technology as well as the method of the power spectrum elimination applied tofixed-frequency inhibition in traditional detection. The second part introduces compressivesampling theory including sparsity expression of signal, design of measurement matrix andreconstruction, then we verify the feasibility of the theory by simulation. The third part introducestwo typical implementation structures of AIC: direct type and pre-modulation. According to thecharacteristics of ultra wideband frequency hopping signal characteristics, the simulation resultsshow that direct type is more suitable for the frequency hopping signal efficiently acquisition. The fourth part proposed three methods of fixed-frequency inhibition in the compressive sampling offrequency hopping signal and constructed the fixed-frequency inhibition model of the compressivesampling of frequency hopping signal. Through the simulation resultes, we proved that the structurenot only can realize fixed-frequency inhibition, but also can finish the reconstruction of frequencyhopping signal with high probability.