A security signal transmission method performed by a first communication node includes estimating a radio channel between the first communication node and a second communication node; classifying all subcarriers into a first subcarrier group for transmitting a data signal and a second subcarrier group for transmitting a jamming signal based on estimated channel information; generating data symbol(s) by allocating the data signal to subcarriers of the first subcarrier group; generating jamming symbol(s) by allocating the jamming signal to subcarriers of the second subcarrier group; generating a first control symbol to which a first control signal is mapped, the first control signal including a first reference value used to restore the data symbols at the second communication node; and transmitting the data symbol(s), the jamming symbol(s), and the first control symbol to the second communication node.

A method is provided for controlling communication in wireless charging. The method comprises: controlling wireless power transfer with a device; receiving a communication signal from the device; generating a jamming signal based on the communication signal from the device; and applying the jamming signal to the communication signal to obtain a jammed communication signal. A device is also provided for controlling communication in wireless charging. The device is configured to control wireless power transfer and receive a communication signal. The device comprises: a jamming circuit configured to generate a jamming signal based on the received communication signal, wherein the device is further configured to apply the jamming signal to the received communication signal to obtain a jammed communication signal.

A jamming device includes a periodic signal generating circuit configured to generate a periodic signal, a noise generating circuit configured to generate a noise signal, and a sweep-signal generating circuit coupled to the periodic signal generating circuit and the noise generating circuit. The sweep-signal generating circuit is configured to generate a frequency-sweep signal based on the periodic signal and the noise signal.

Disclosed are a secure communication device and a secure communication method using an artificial noise scheme. The secure communication method between a multi-antenna legal transmission device and a multi-antenna legal reception device includes determining a power allocation ratio for a system parameter, by the legal reception device, generating a transmission signal including a secret information message based on the determined power allocation ratio and artificial noise, and transmitting the generated transmission signal to the legal reception device.

A passive altimeter system comprising an angle between a point and a central boresight that is determined from distortion parameters of a lens in an infrared sensor in a countermeasure system on a mobile platform wherein the infrared sensor captures a first image for determining a distance between the platform and one of (i) a ground surface and (ii) a target, and the passive altimeter system further comprising a dimensional distance between two points in the first image that is determined from a secondary source external to the countermeasure system, and a processor to triangulate the distance between the platform and one of (i) the ground surface and (ii) the target based on the dimensional distance and the angle.

Methods and apparatuses for addressing open space noise are disclosed. In one example, a method for masking open space noise includes optimizing a recorded naturally occurring sound signal. The method also includes outputting the optimized recorded naturally occurring sound signal from a plurality of speakers distributed in the open space. Further, the method includes displaying a natural system complementing the optimized recorded naturally occurring sound signal.

A jamming radio signal is selectively outputted based on an access signal. The jamming radio signal is configured to prevent an interrogation signal of a vehicle to complete an authentication of a vehicle key of the vehicle.

The game table reading system comprises reading antennas for each of a plurality of reading areas of a game table, read-restriction antennas for each of the plurality of the reading areas, the read-restriction antennas restricting the RFID tag embedded in a game token placed in the corresponding reading area from being read by the reading antenna corresponding to the other adjacent reading areas, a reading control device that controls the reading antennas, and a read-restriction control device that controls the read-restriction antennas. The read-restriction control device causes the read-restriction antennas corresponding to the reading areas adjacent to the reading areas corresponding to the reading antenna that the reading control device causes to read, in synchronization with the reading control device.

Disclosed are an anti-drone method using a GPS spoofing signal and a system thereof. According to an embodiment of the inventive concept, an anti-drone method may include injecting a GPS spoofing signal to analyze a drone feature of a target drone and hijacking the target drone by injecting a GPS spoofing signal into the target drone based on a drone hijacking strategy corresponding to the analyzed drone feature among predefined drone hijacking strategies. The analyzing of the drone feature may include injecting the GPS spoofing signal to analyze a safety device mechanism (GPS fail-safe) and a path-following algorithm of the target drone.

An exemplary radio fingerprint-based indoor localization method and system is disclosed that is resistant to spoofing or jamming attacks (e.g., at nearby radios, e.g., access points), among other types of interference. The exemplary method and system may be applied in the configuring of a secured convolutional neural network (S-CNNLOC) or secured deep neural network configured for attack-resistant fingerprint-based indoor localization.