Advanced Secure Signal Transmission

To effectively employ the CCS capability, Operators must project and be able to counteract target signal waveforms with the utmost precision. Adversary communication networks continue to increase in complexity and in their ability to thwart Electronic Warfare (EW) systems like CCS. Astrapi created physical-layer signal security called “Symbol Waveform Hopping” (SWH) based on novel symbol waveforms providing advanced signal security capability. Based on an innovation in signal mathematics and new symbol waveform design tactics, techniques, and procedures (TTPs), Signal Waveform Hopping forces an adversary to distinguish between many more possible symbol waveforms than is possible given an operational signal-to-noise power ratio (SNR). Within 21 months, Astrapi will deliver a prototype SWH TTP in a Software Defined Radio (SDR) that implements SWH in a CCS context. The availability of this novel physical-layer signal protection capability  to CCS could increase the lethality of the system. Symbol Waveform Hopping (SWH) is built on top of Astrapi’s Spiral Modulation (SM) technology, which greatly increases the bandlimited symbol waveform design space. SWH uses this expanded waveform design space to improve security and transmission efficiency. As with traditional signal modulation, each symbol alphabet (set of component bit sequences) is paired with an equivalent alphabet of symbol waveforms for transmitting those bits. However, in SWH, there are multiple such symbol waveform alphabets in use over time. With this added complexity, the SNR makes it impossible for an adversary to determine the time-amplitude values transmitted, blocking any further attempt at interception. SWH is similar to Frequency Hopping (FH) in that both change an aspect of the signal at the physical layer according to a pseudo-random sequence known only to the sender and intended receiver. But whereas FH operates in the frequency domain, SWH operates in the time domain. FH in principle may be defeated if enough spectrum is analyzed. SWH is in principle unbeatable if the pseudo-random sequence is not known.