Interception of frequencyhopped spreadspectrum signals
Abstract
A frequencyhopped spreadspectrum signal is modeled as a sinusoid that has one of N random frequencies. Coherent and noncoherent interception receiver structures based on NeymanPearson detection theory are determined. Under the assumption that there is a single hop per detection period, the optimum receiver structure is shown to consist of a bank of matched filters called the average likelihood (AL) receiver. A suboptimum structure called the maximum likelihood (ML) receiver is also analyzed. It is shown that AL and ML receivers have essentially the same performance. Simple formulas that relate the probability of detection, PD, to the probability of false alarm, PF, and the signaltonoise ratio (SNR) for large N are derived. Receiver structures are also derived and analyzed for the case where the signal hops a number of times in one detection interval. This may correspond to the detection of a multihop signal in one symbol interval or to detection based on integration over a number of symbol intervals. The relationships of PD to PF, for both coherent and noncoherent multiplehop receivers, are examined.
 Publication:

IEEE Journal on Selected Areas in Communications
 Pub Date:
 June 1990
 Bibcode:
 1990IJSAC...8..853B
 Keywords:

 False Alarms;
 Frequency Hopping;
 Interception;
 Spread Spectrum Transmission;
 Maximum Likelihood Estimates;
 Signal To Noise Ratios;
 Communications and Radar