A multi-user (MU) multiple-input/multiple-output (MU MIMO) module for a fifth-generation (5G) software-defined radio (SDR) network environment is disclosed. In embodiments, the MU MIMO module of a transmitting SDR system of a 5G mobile ad hoc network (MANET) or other peer-to-peer directional network receives feedback from a receiving SDR system based on a prior or current frame and generates, based on the feedback, a compound transmission security (TRANSEC) encryption key for a subsequent frame. The compound TRANSEC encryption key encrypts the transmission of the subsequent frame through a combination of frequency-hopping encryption codes, orthogonality-hopping encryption codes, and dynamic pseudorandom distribution of transmitting power among antenna elements to simulate multipath hopping. The SDR system may include an antenna controller capable of managing dynamic power distribution according to the compound TRANSEC encryption keys as well as directionality shifts and beamforming operations to evade jammers detected within the 5G network environment.

The disclosed invention uses artificial intelligence (AI) algorithms for detecting and classifying radiofrequency transmissions to model and simulate an RF environment. AI or machine learning (ML) algorithms further assist in determining optimal modulation, bandwidth and center frequency placement of a transmit signal to either fully and efficiently exploit unused spectrum in the RF environment, or to camouflage the signal to evade detection, and therefore interception while providing enough fidelity to the receiver to remain detectable. Such signal shaping is done while maintaining small SWaP-C footprint for system component hardware.

Methods, systems, and devices for channelizing a wideband waveform for transmission on a spectral band comprising unavailable channel segments are described. Generally, the described techniques provide for transmitting and receiving wideband waveforms when channels of a system bandwidth are unavailable for transmission. A transmitter may separate a first wideband signal into segments, with each segment a bandwidth corresponding to a channel of the system bandwidth, and may map the segments to the available channels. The transmitter may combine the mapped segments into a second wideband waveform and transmit the second wideband waveform using the available channels. A receiver may receive a first wideband signal waveform and may separate the first wideband signal waveform into segments, de-map the segments and combine the de-mapped segments into a second wideband waveform for demodulation. The techniques may be used to transmit and receive wideband waveforms over tactical data links.

A system may include a first radio comprising a first radio processor, a first radio modem, and a first radio transmitter configured to transmit non-hopping transmissions and hopping transmissions. The system may further include a second radio comprising a second radio processor, a second radio modem, and a second radio hopping receiver, wherein the second radio hopping receiver is a non-staring second radio receiver. The first radio may be configured to: receive a message and a destination for the message, the destination being the second radio; upon a determination that the destination has a non-staring receiver, store the message; determine a time interval start time for a cyclical hop pattern associated with the second radio; output the message from the memory to the first radio modem; output the message from the first radio modem to the first radio transmitter; and/or transmit the message to the second radio.

A reactive jamming software defined radio (SDR) apparatus to target Frequency Hopping Spread-Spectrum (FHSS) signals includes a peripheral module for SDR processing; a reactive jamming hardware IP core that implements time-sensitive operations on a field programmable gate array (FGPA); and a host computer that implements non-time-critical operations, such as jammer configuration, logging, and strategy composition.

Described herein are unmanned water vehicles, platforms, and media for stealthy, low-power, and long range electronic warfare and signals intelligence. The unmanned water vehicles, platforms, and media herein are capable of capturing communication between ships, land and air and ground stations across multiple spectra, and transmitting real-time disambiguated transmission recordings and source positions.

Methods, systems, and devices for channelizing a wideband waveform for transmission on a spectral band comprising unavailable channel segments are described. Generally, the described techniques provide for transmitting and receiving wideband waveforms when channels of a system bandwidth are unavailable for transmission. A transmitter may separate a first wideband signal into segments, with each segment a bandwidth corresponding to a channel of the system bandwidth, and may map the segments to the available channels. The transmitter may combine the mapped segments into a second wideband waveform and transmit the second wideband waveform using the available channels. A receiver may receive a first wideband signal waveform and may separate the first wideband signal waveform into segments, de-map the segments and combine the de-mapped segments into a second wideband waveform for demodulation. The techniques may be used to transmit and receive wideband waveforms over tactical data links.

Transmitting a signal from a transmitter. A method includes identifying a threshold spectral flux density for a given physical location. The method further includes, as a result of identifying the threshold spectral flux density, transmitting a signal at a power level causing the signal to be below the spectral flux density at the given physical location, the signal being transmitted at a data rate. The method further includes receiving feedback from a receiver indicating the signal-to-noise ratio of the signal at the receiver. The method further includes adjusting the data rate of the signal based on the feedback. The method further includes continuing transmitting the signal at the adjusted data rate and power level.

Transmitting a signal from a transmitter. A method includes identifying a threshold spectral flux density for a given physical location. The method further includes, as a result of identifying the threshold spectral flux density, transmitting a signal at a power level causing the signal to be below the spectral flux density at the given physical location, the signal being transmitted at a data rate. The method further includes receiving feedback from a receiver indicating the signal-to-noise ratio of the signal at the receiver. The method further includes adjusting the data rate of the signal based on the feedback. The method further includes continuing transmitting the signal at the adjusted data rate and power level.

In embodiments, a communication node of a multi-node communication network includes a controller communicatively coupled to a communication interface, wherein the controller is configured to: acquire a data payload to be transmitted based on a randomized transmission interval; duplicate a bit sequence of the data payload with a selected spreading pattern; perform bit-to-symbol mapping of the bit sequence based on a selected M-ary number to generate a data payload symbol sequence; randomize a location or value of one or more pilot symbols and one or more data carriers of the data payload symbol sequence; transform frequency-domain symbols of the data payload symbol sequence into time-domain symbols to generate a time-domain data payload signal; remove amplitude fluctuation of the data payload signal to generate a phasor data payload signal; and transmit the phasor data payload signal to at least one additional communication node of the multi-node communication network.