2020/05/02 by Alexei V. Nikitin, Ruslan L. Davidchack, Nikitin, Alexei V. +1
Engineering · #FOS: Electrical engineering #Optical Network Technologies #Power Line Communications and Noise #Signal Processing (eess.SP) #electronic engineering #graph theory and CDMA systems #information engineering
paper · pdf · doi:10.48550/arxiv.2005.00734
openalex publication_date 2020/05/02 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
In contrast to other spread-spectrum techniques, wideband pulse trains with\nrelatively low pulse arrival rates may be considered unsuitable for covert\ncommunications. The high crest factor of such trains can be extremely\nburdensome for the transmitter hardware, and it makes the pulse trains easily\ndetectable even at very low signal-to-noise ratios. In addition, it may appear\nthat sharing the wideband channel by multiple users would require explicit\nallocation of the pulse arrival times for each sub-channel, which would be\nimpractical in most cases. On the other hand, messaging by wideband pulse\ntrains has many appealing features. Among those are the ease of synchronous as\nwell as asynchronous pulse detection, and on-the-fly channel reconfigurability\n(e.g. changing the spreading factor). Favorably, the crest factor of a pulse\ntrain, as well as its apparent temporal and amplitude structure, can be easily,\nand reversibly, controlled by simple linear filtering. For example, a\ntransmitted pulse train can be made statistically indistinguishable from the\nGaussian component of the channel noise (e.g. the thermal noise) observed in\nthe same spectral band, while the received signal will be the designed\nhigh-crest-factor wideband pulse train. In this paper, we utilize the so-called\npulse pileup effect to perform such reversible control of the pulse train\nstructure, enabling a wider use of this approach for synthesis of robust\nlow-SNR covert communication links. We place a particular focus on the\nsynchronous pulse detection in the receiver, that provides a better utilization\nof the channel spectrum.\n