An all-digital spread-spectrum type communications system employing chaotic symbol modulation. The system includes a transmitter having a symbol mapper that converts a series of information bits to a series of bit symbols, a digital chaos modulator employing an M-ary chaotic shift keying (M-CSK) architecture for chaotically spreading the bit symbols in the digital domain, where the chaos modulator includes a separate chaos generator for each of the M-CSK symbols, and a digital-to-analog converter (DAC) for converting the chaotic modulated bit symbols to an analog signal for transmission. The system also includes a receiver responsive to the analog signal from the transmitter and generating a received signal therefrom. The receiver performs signal acquisition and tracking on the received signal using a look-up table, a transmitter ID and a receiver ID in the received signal, de-spreading and de-modulation on the received signal and bit removal from the symbols in the received signal.

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 method for orthogonal wavicle division multiple-access modulation-demodulation includes: generate an orthogonal quantum chaotic data wavicles matrix and a quantum chaotic sync wavicle according to a key including the required data bit-rate, the parallel symbols transmission scheme, the signal updating/sampling rate, the available energy spectrum range, and either the ID of the source user or other perturbation schemes agreed upon by the transmitter and receiver; generate and transmit a modulated quantum chaotic wavicle by orthogonal wavicle division multiplexing modulating a serial bits segment to an orthogonal quantum chaotic data wavicles matrix plus a quantum chaotic sync wavicle; and retrieve the serial bits segment by orthogonal wavicle division multiplexing demodulating the received signal synchronously with an orthogonal quantum chaotic data wavicles matrix plus a quantum chaotic sync wavicle.

A reconstruction method for DCSK signals is provided. An information bit sequence to be transmitted is acquired, which is processed by serial-to-parallel conversion. A processed information bit sequence is input into a modulator for modulation to obtain a modulated signal matrix. Cross multiplication is performed between the modulated signal matrix and a chaotic signal to obtain an original information-bearing matrix, which is reconstructed according to a predetermined reconstruction matrix to obtain an information-bearing reconstruction matrix. A transmission symbol is generated according to the information-bearing reconstruction matrix and a reference signal matrix in combination with frame structure information of the transmission symbol, and is sent to a receiving end via a wireless network to demodulate a received signal according to a reconstruction matrix. A reconstruction device for DCSK signals is also provided.

This application discloses a communications chip structure, including: a channel selection module, configured to receive an input signal, where the input signal is a signal of a preset narrow bandwidth span or a signal of a preset wide bandwidth span; and a digital baseband module, configured to control the channel selection module to select a first sampling and quantification channel when the input signal is a signal of the preset narrow bandwidth span, or control the channel selection module to select a second sampling and quantification channel when the input signal is a signal of the preset wide bandwidth span. The channel selection module is further configured to send the input signal to the first sampling and quantification channel or the second sampling and quantification channel for sampling and quantification.

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 sub-sampling system that is part of a modulator in a transmitter employing a chaos based architecture and including a symbol mapper and a chaos generator. The system includes M-number of channels each receiving a sequence of chaos samples from the generator and a delay device in all of the channels except one that delay the chaos samples at different delay times. The system also includes a sub-sampler in all of the channels that receive the delayed samples, where each sub-sampler outputs every predetermined one of the chaos samples and a register in each channel each storing a predetermined number of the sub-sampled chaos samples. A selection switch responsive to the stored sub-sampled chaos samples from the registers, where the selection switch is responsive to a selection signal from the symbol mapper that selects one of the registers to output the sequences of stored sub-sampled chaos samples from the system.

A communication method for phase separation differential chaos shift keying (DCSK) based on a second order hybrid system (SOHS) is provided. The method includes the following steps. At Step 1: communication system parameters are set. At Step 2: binary information to be transmitted are prepared. At Step 3: the chaotic signal u(t) is generated. At Step 4: the chaotic signal is prepared to be transmitted. At Step 5: a received signal is demodulated. At Step 6: a chaotic matched filtering operation is performed on the demodulated reference signal and the demodulated information bearing signal. At Step 7: optimal signal to noise ratio (SNR) points are extracted in a sampling way. At Step 8: polarity of each symbol is determined to obtain a recovered signal.

Demodulating a modulated signal. A method may include receiving a modulated signal, wherein the modulated signal is a signal modulated according to a modulation function varying faster than the signal. The modulation function is a function of the signal. The modulated signal received is demodulated with an artificial neural network system, or ANN system, which is trained to identify bit values from signal patterns as caused by the modulation function, by identifying bit values from patterns of the modulated signal received. Related modulation and demodulation systems are disclosed.

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.