An environmental sound generating apparatus generates an environmental sound signal representing an environmental sound that forms sound environment by being emitted. The environmental sound has at least one chain of phonemes constituted of individual phonemes which sound-emission start timings as one of attributes thereof are sequentially shifted. A plurality of subgroups are prepared each formed by combining individual plural pitches from pitches constituting a primary pitch group that is a group of phonemes musically treated as consonances if sounded simultaneously. One of the plurality of subgroups selected at random is set to each of the sections of the chain of phonemes, and each of the individual phonemes of each section of the chain of phonemes is set to a pitch selected at random from the plural pitches constituting the selected subgroup to attain hypersonic effects.

A distributed antenna system with a plurality of remote radio units is disclosed. The distributed antenna system includes a jammer signal generator for generating a jammer signal in at least one frequency range to be blocked on detection of an uplink signal in a coverage area, as well as at least one antenna element for transmitting the generated jammer signal in the coverage area. The jammer signal will ensure that any mobile devices or stations within the coverage area are unable to transmit radio signals as the frequency range(s) on which the radio signals should be transmitted are blocked by the jammer signal.

A sound masking system according to the invention is disclosed in which one or more sound masking loudspeaker assemblies are coupled to one or more electronic sound masking signal generators. The loudspeaker assemblies in the system of the invention have a low directivity index and preferably emit an acoustic sound masking signal that has a sound masking spectrum specifically designed to provide superior sound masking in an open plan office. Each of the plurality of loudspeaker assemblies is oriented to provide the acoustic sound masking signal in a direct path into the predetermined area in which masking sound is needed. In addition, the sound masking system of the invention can include a remote control function by which a user can select from a plurality of stored sets of information for providing from a recipient loudspeaker assembly an acoustic sound masking signal having a-selected sound masking spectrum.

A monitoring system using cooperative jamming and spoofing according to an embodiment of the present disclosure includes a spoofing relay to amplify and relay an illegal signal detected from an illegal transmitter according to a preset amplification coefficient, a cooperative jammer to transmit a jamming signal for changing the quality of a communication channel to an illegal receiver with a preset transmit power, and a monitor to calculate the amplification coefficient and the transmit power so that an information monitoring amount is maximum based on the illegal signal received from the spoofing relay.

Disclosed is an anti-eavesdropping method for the Internet of Vehicles (IoV) based on intermittent cooperative jamming. The method comprises: on the premise of effectively preventing an illegitimate user V.sub.e from information eavesdropping, first establishing optimization problems for the purpose of minimizing an energy consumption of a cooperative jamming user V.sub.j; analyzing unique communication characteristics of the IoV based on the Wireless Access in Vehicular Environments (WAVE) protocol, to obtain time structures of physical-layer data packets in the IoV and physical-layer data packet duration; and calculating the shortest physical-layer data packet duration in the IoV; then solving an optimal cooperative jamming scheme for any available power range for the cooperative jamming user V.sub.j; and finally, conducting, by the cooperative jamming user V.sub.j, periodic repetition according to the solved optimal cooperative jamming schemes in a period of data transmission between legitimate users, until transmission between the legitimate users ends.

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.

A controller for controlling wireless communication between a node and a master device in a wireless network; wherein the controller comprises a processor arranged for: determining a first directionally restricted jamming area relative to the node; determining a second directionally restricted jamming area relative to the master device; controlling a first directional antenna to transmit a first jamming signal in the first determined directionally restricted jamming area during a predetermined time period; and controlling a second directional antenna to transmit a second jamming signal in the second determined directionally restricted jamming area during the predetermined time period.

According to an embodiment, a communication control device includes a communication unit and a jamming control unit. The communication unit wirelessly communicates with a first device and uploads information acquired from the first device to a second device via a network. The jamming control unit allows jamming radio waves to be output to interfere with wireless communication between the first device and a device other than the communication control device, the device being to perform wireless communication in a communication band used by the first device.

A system for providing distributed wireless communication for at least one user equipment with connectivity and/or security against at least one eavesdropper is provided. The system includes wireless communication units and a scheduling unit. In this context, the scheduling unit is configured to schedule a first subset of the wireless communication units for radar sensing in order to gather radar sensing information with respect to the at least one user equipment, the environment of the at least one user equipment, the at least one eavesdropper, the environment of the at least one eavesdropper, or any combination thereof. In addition to this, the scheduling unit is configured to schedule a second subset of the wireless communication units for distributing the wireless communication with respect to the at least one user equipment on the basis of the radar sensing information.

A monitoring system using cooperative jamming and spoofing according to an embodiment of the present disclosure includes a spoofing relay to amplify and relay an illegal signal detected from an illegal transmitter according to a preset amplification coefficient, a cooperative jammer to transmit a jamming signal for changing the quality of a communication channel to an illegal receiver with a preset transmit power, and a monitor to calculate the amplification coefficient and the transmit power so that an information monitoring amount is maximum based on the illegal signal received from the spoofing relay.