A family of wavelet-related sequences as a basis for an LPI/D communications system prototype

The authors introduce a family of sequences which is well suited for use in covert communications applications which employ direct-sequence spectral spreading, and they discuss a hardware testbed which has been designed to demonstrate a covert communications system prototype that incorporates these sequences. The sequences are constructed using a modified Haar wavelet coefficient matrix, and various properties of the sequences are useful for obtaining a relatively high degree of covertness against radiometric and cyclic feature detection. In addition, the sequences can be designed so that the distribution of sequence sample values approximates that for a sequence drawn from an arbitrary noise background, and the authors describe a scenario in which this attribute leads to enhanced signal covertness.<>