Chaotic digital code-division multiple access (CDMA) communication systems

A method of communication between first and second code-division multiple access devices that transmit selected information therebetween via a selected medium, said method comprising the steps of:

• a. chaotically generating a seed signal;
• b. applying said seed signal of step a. to a first spectrum spreading device in said first code-division multiple access device to generate a first spread spectrum signal in said first code-division multiple access device;
• c. modulating said first spread spectrum signal from step b. with said information to be transmitted by said first code-division multiple access device;
• d. applying said modulated signal of step c. to said medium for transmission to said second code-division multiple access device;
• e. applying said seed signal of step a. to a second spectrum spreading device in said second code-division multiple access device to generate a second spread spectrum signal in said second code-division multiple access device;
• f. multiplying said modulated signal received from said medium of step d. together with said second spread spectrum signal of step e. to create a combined signal;
• and
• g. demodulating said combined signal of step f. to generate a recovered information signal.

A code-division multiple access device to transmit and receive selected information to and from other code-division multiple access devices, said code-division multiple access device comprising:

• a processor coupled to each component of said code-division multiple access device to control the transmit and receive operations thereof;
• a message interface disposed to process a message signal for transmission and to provide a received message signal to and from a message source;
• a spectrum spreading device disposed to receive a chaotic seed signal to control the generation of a carrier signal;
• an input/output transducer disposed to deliver a message signal to a selected transmission medium for transmission to a second code-division multiple access device or to receive a message signal from said selected medium that was transmitted from a second code-division multiple access device;
• a multiplier coupled to said spectrum spreading device, said message interface, and said input/output transducer to modulate said carrier signal with said message signal with the modulated signal applied to said input/output transducer in a transmit mode, and to multiply said received message signal from said input/output transducer with said carrier signal to create a received product signal in a receive mode;
• and
• a demodulator coupled between said multiplier and said message interface to demodulate said received product signal to create said received message signal that is delivered to said message interface.

A code-division multiple access communication system comprising:

• a chaotic device to generate a chaotic seed signal;
• a selected transmission medium;
• a first code-division multiple access device;
• a second code division multiple access device;
• wherein each of said first and second code-division multiple access devices are disposed to transmit and receive selected information between each other, and each includes:
• a processor coupled to each component of said code-division multiple access device to control the transmit and receive operations thereof;
• a message interface disposed to process a message signal for transmission and to provide a received message signal to and from a message source;
• a spectrum spreading device disposed to receive said chaotic seed signal to control the generation of a carrier signal;
• an input/output transducer disposed to deliver a message signal to said selected transmission medium for transmission to another code-division multiple access device or to receive a message signal from said selected transmission medium that was transmitted from another code-division multiple access device;
• a multiplier coupled to said spectrum spreading device, said message interface, and said input/output transducer to modulate said carrier signal with said message signal with the modulated signal applied to said input/output transducer in a transmit mode, and to multiply said received message signal from said input/output transducer with said carrier signal to create a received product signal in a receive mode;
• and
• a demodulator coupled between said multiplier and said message interface to demodulate said received product signal to create said received message signal that is delivered to said message interface.