An electronic control unit comprises circuitry to receive a combined signal via a vehicle bus of a vehicle, wherein the combined signal contains a combination of a data signal and a watermark signal, which can be a radio frequency (RF) signal or an analog baseband signal, wherein the data signal includes a message, circuitry to extract a watermark from the watermark signal, circuitry to verify the watermark based on a comparison of the watermark with a pre-defined watermark, circuitry to extract the data signal from the combined signal and obtain the message from the data signal, and circuitry to authenticate the message based on the verification of the watermark.

A system, method, and computer program product for chaotically generating a pseudorandom number sequence, such as for use in spread spectrum communications systems and in cryptographic systems. Chaotically generated pseudorandom numbers are not cyclostationary in nature, so output values encoded via such non-cyclostationary bases have no clear correlations. Spread signal communications systems using chaotically generated spreading codes thus operate without rate line artifacts, increasing their resistance to signal detection and to determinations of underlying signal chip rates and signal symbol rates. Broadcasts and guided transmissions (including either conductive wire or optical transmission media), in both radio frequency and optical systems are supported. Common spread spectrum communications systems including DSSS and FHSS may be strengthened through the use of chaotically generated spreading codes. Similarly, keys and nonces generated for cryptographic systems may be improved over those based on conventionally generated pseudorandom numbers.

Example communication systems and methods are described. In one implementation, a method receives a first chaotic sequence of a first temporal length, and a second chaotic sequence of a second temporal length. The method also receives a data symbol for communication to a destination. Based on the data symbol, the second chaotic sequence is temporally shifted and combined with the first chaotic sequence to generate a composite chaotic sequence. The first chaotic sequence functions as a reference chaotic sequence while the second chaotic sequence functions as a data-carrying auxiliary chaotic sequence.

An electronic control unit comprises circuitry to receive a combined signal via a vehicle bus of a vehicle, wherein the combined signal contains a combination of a data signal and a watermark signal, which can be a radio frequency (RF) signal or an analog baseband signal, wherein the data signal includes a message, circuitry to extract a watermark from the watermark signal, circuitry to verify the watermark based on a comparison of the watermark with a pre-defined watermark, circuitry to extract the data signal from the combined signal and obtain the message from the data signal, and circuitry to authenticate the message based on the verification of the watermark.

A transmitter for a chaos communications system employing chaotic symbol modulation that perform auto-indexing, temporal gain control, increased path diversity and sequence lock up prevention. The transmitter includes a symbol mapper that converts a series of information bits to a series of bit symbols, and a chaos modulator providing chaotic spreading modulation of the bit symbols. The chaos modulator includes a plurality of chaos generators, one for each bit symbol, providing a chaos sequence for the bit symbols. Each chaos modulator includes a RAM/ROM that provides auto-indexing where a chaos sequence output from the RAM/ROM is fed back to an input of the RAM/ROM from which a chaos sequence at a next address in the RAM/ROM is selected as the output of the modulator.

A transmitter for a chaos communications system employing chaotic symbol modulation that perform auto-indexing, temporal gain control, increased path diversity and sequence lock up prevention. The transmitter includes a symbol mapper that converts a series of information bits to a series of bit symbols, and a chaos modulator providing chaotic spreading modulation of the bit symbols. The chaos modulator includes a plurality of chaos generators, one for each bit symbol, providing a chaos sequence for the bit symbols. Each chaos modulator includes a RAM/ROM that provides auto-indexing where a chaos sequence output from the RAM/ROM is fed back to an input of the RAM/ROM from which a chaos sequence at a next address in the RAM/ROM is selected as the output of the modulator.

Disclosed is an air conditioner. The air conditioner of the present disclosure includes: a plurality of indoor units configured to be distributed and installed in a plurality of floors in a building; a controller configured to monitor and control the plurality of indoor units; and a wireless communication unit configured to transmit and receive data by the controller, the plurality of indoor units, and one outdoor unit by using a wireless communication method; wherein the wireless communication unit comprises a transmitter and a receiver using a Sub-GHz band frequency, wherein the transmitter includes: an optical orthogonal code generating unit configured to first cipher source data using an optical orthogonal code; and a narrow-band chaotic signal generating unit configured to secondarily cipher by using a chaotic signal, wherein the data is sequentially encrypted through the optical orthogonal code generating unit and the narrowband chaotic signal generating unit and then transmitted.

The present disclosure discloses an M-ary DCSK method based on chaotic shape-forming filtering. The method includes the following steps: at S1, parameters of a communication system are set; at S2, HP information and LP information to be sent in each time slot are prepared; at S3, the information to be sent is modulated; at S4, a chaotic carrier is generated through a chaotic shape-forming filter; at S5, a transmitted signal is prepared; at S6, down-carrier frequency and matched filter is performed to a received signal; at S7, the sampling of a maximum SNR point is performed to an output signal of a matched filter; at S8, the decision of high priority information bits is resumed; and at S9, the decision of low priority information bits is resumed.

A communications system that pseudo-randomly dithers the widths of chips that are multiplied by bit symbols for spread spectrum purposes. The system includes a first random sequence generator that generates a first sequence of random numbers at a sample rate and a decision processor responsive to the first sequence of random numbers that generates a separate command at the sample rate each time one of the random numbers exceeds a predetermined threshold. The system further includes a second random sequence generator that generates select random numbers, where the second random number generator changes the select random number each time it receives one of the commands. The system also includes a chip width processor responsive to the random numbers from the second random sequence generator, where the chip width processor selects a new set of chips each having a certain width in response to receiving each random number.

The present disclosure discloses an M-ary DCSK method based on chaotic shape-forming filtering. The method includes the following steps: at S1, parameters of a communication system are set; at S2, HP information and LP information to be sent in each time slot are prepared; at S3, the information to be sent is modulated; at S4, a chaotic carrier is generated through a chaotic shape-forming filter; at S5, a transmitted signal is prepared; at S6, down-carrier frequency and matched filter is performed to a received signal; at S7, the sampling of a maximum SNR point is performed to an output signal of a matched filter; at S8, the decision of high priority information bits is resumed; and at S9, the decision of low priority information bits is resumed.