A communication system may include a radio frequency (RF) detector and an RF transmitter having a selectable hopping rate and a selectable hopping frequency window. A controller may be configured to operate the RF transmitter at a selected hopping rate and at a selected hopping frequency window based upon the RF detector.

A securely pre-coded orthogonal frequency division multiplexing (SP-OFDM) system includes a transmitter configured to transmit a secure transmit signal through a dynamic constellation and a receiver configured to recover the original signal from the received secure transmit signal. It is aimed to reinforce the physical layer security of wireless communications under hostile interference. Potential applications include 4G and 5G communication systems, ASTC3.0 HDTV systems, WiFi systems, and any future wireless systems that utilize OFDM.

Techniques are described for the exchange of control signals between a controlled unmanned aircraft (i.e. drone) and a ground control station and for the transmission of communication signals, such as video, from the drone to the ground control station so that the signals are more difficult to intercept or jam. The video signal transmitted from the drone can be an analog RF signal employing one or more of video scrambling, RF signal inversion, hopping, usage of a wide frequency range and other techniques. To secure the control signals between the drone and the ground control station, techniques can include hopping, encryption and use of a wide frequency range.

A test system for testing follower jammer robustness of a radio is described. The test system comprises a signal analyzer and a signal generator that are connected with each other via a communication connection. The signal analyzer is configured to record a radio communication signal and to convert the recorded radio communication signal to a processing signal that is compatible for the communication connection. The signal generator is configured to add at least one delayed signal to the processing signal. Further, a method of testing follower jammer robustness of a radio is described.

Systems and methods for reprogramming a Single Channel Ground and Airborne Radio System (SINCGARS) having a SINCGARS frequency-hopping waveform with a fixed retuning period operable in a network of SINCGARS. A system includes a controller programmed with a modified frequency-hopping waveform having one or more retuning periods, each of the one or more retuning periods being shorter in duration than the fixed retuning period of the conventional SINCGARS waveform, the modified frequency-hopping waveform compatible with each of the SINCGARS in the network. An interface is provided for programming each of the devices with the modified waveform.

Systems and methods for reprogramming a Single Channel Ground and Airborne Radio System (SINCGARS) having a SINCGARS frequency-hopping waveform with a fixed retuning period operable in a network of SINCGARS. A system includes a controller programmed with a modified frequency-hopping waveform having one or more retuning periods, each of the one or more retuning periods being shorter in duration than the fixed retuning period of the conventional SINCGARS waveform, the modified frequency-hopping waveform compatible with each of the SINCGARS in the network. An interface is provided for programming each of the devices with the modified waveform.

A communication system including an analog front end and an automatic gain controller. The analog front end includes at least one amplifier for amplifying a received analog signal and an analog to digital converter that converts the analog signal to digital samples. The automatic gain controller includes comparator circuitry, counter circuitry, and a gain controller. The comparator circuitry compares each of the digital samples with an upper threshold and a lower threshold. The counter circuitry counts a high count number of the digital samples having magnitudes that are greater than the upper threshold during each count window and counts a low count number of the digital samples having magnitudes that are less than the lower threshold during the count window. The gain controller adjusts a gain of the at least one amplifier by an amount based on the high count number and the low count number.

The present disclosure provides systems and methods for enhanced wireless communication security. The preambles used for the identification of an upcoming wireless communication may be periodically changed (e.g., dynamic), on a time basis, based on a secret key function shared between the communicating parties. In this way, only the intended parties are able to recognize the start of an ongoing communication, synchronize with the transmitters, and access the information contained therein. An attacker, being unaware of the specific preamble sequence used for the synchronization, will not recognize the pattern of the communication, and thus will be unable to recognize when communications are ongoing. Additional authentication measures may also be implemented with the transmissions.

A secure wireless transceiver, such as a link 16 transceiver, receives signals using an antenna array having an SOC associated with each antenna element in the array. The SOC's digitize and channelize received data for transmission to a message nulling system that mitigates jamming. The antenna array can be conformal, and can replace an existing Link 16 blade. The disclosed transceiver can be a modified CMN-4 transceiver with digitizing and channelizing moved to the SoC's, and replaced by the nulling system. The transceiver uses applicable TRANSEC information to assign received data to the logical Link 16 channels before nulling, and embodiments apply nulling only to channels of interest, thereby improving the nulling and reducing side lobes. Embodiments distinguish between desired and unwanted signals based on known Link 16 signal features and/or situational awareness, rather than signal amplitudes, thereby enabling nulling of even weak jamming signals.

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.