Measure of covertness based on the imperfect synchronization of an eavesdropper in Random Communication Systems

Random Communication Systems (RCSs) given in the literature have assumed perfectly synchronized transmitter and receiver. However, in this paper, instead of assuming perfect synchronization approach in RCSs, the effects of imperfect synchronization (IS) on Skewed Alpha-Stable Noise Shift Keying (SkαS-NSK) based RCS have been observed through simulations. The Bit Error Rate (BER) performance of the eavesdropper with respect to his synchronization error in SkαS-NSK based RCS, has been analyzed. An expression for the probability of an eavesdropper to decode the binary information (i.e. Eavesdropping Probability) in SkαS-NSK based RCS, has been derived. The criterion (i.e. Covertness Value) to measure the covertness level of RCSs has also been proposed. The BER performance of an eavesdropper provides an approximate margin of synchronization error if it can be overcome by an eavesdropper then he can achieve the decoding (i.e. eavesdropping) process.