Transmitter-receiver separation system for full-duplex underwater acoustic communication system

A communication system for underwater acoustic full-duplex communication, the communication system comprising:

• a first transmitter configured to transmit a first signal with a first polarity;
• a second transmitter configured to transmit a second signal with a second polarity, wherein the second polarity is opposite the first polarity, and wherein the first transmitter and the second transmitter are:
• positioned along an axis extending through a center of the first transmitter and a center of the second transmitter;
• and
• separated by a distance approximately equal to a quarter wavelength of a central frequency of the working frequency band;
• a receiver positioned on the axis;
• and
• an adaptive processor in communication with the first transmitter, the second transmitter, and the receiver, wherein the adaptive processor is configured to:
• receive an output signal from the receiver;
• and
• apply a stochastic gradient adaptive filter to the output signal to:
• equalize a first amplitude of the first signal with a second amplitude of the second signal;
• and
• equalize a first delay of the first signal with a second delay of the second signal.

A communication system for underwater acoustic full-duplex communication, the communication system comprising:

• a transmitter;
• and
• a first receiver set comprising a first receiver and a second receiver, wherein the first receiver and the second receiver are:
• separated by a distance approximately equal to a half wavelength of a central frequency of the working frequency band;
• symmetrically positioned along a first axis an equal distance from the transmitter;
• connected in parallel in an opposite polarity;
• and
• configured to:
• output a near-zero signal in response to a signal transmitted by the transmitter;
• and
• output a non-zero signal in response to any signal arriving from a direction different than orthogonal to the first axis.

A communication system for underwater acoustic full-duplex communication, the communication system comprising:

• a first receiver and a second receiver, wherein the first receiver and the second receiver are:
• positioned along an axis extending through a center of the first receiver and a center of the second receiver;
• and
• separated by a distance approximately equal to a quarter wavelength of a central frequency of the working frequency band;
• a transmitter positioned on the axis, wherein the first receiver is configured to receive a first signal from the transmitter, and wherein the second receiver is configured to receive a second signal from the transmitter;
• and
• an adaptive processor in communication with the first receiver and the second receiver, wherein the adaptive processor is configured to:
• receive an output signal from the second receiver;
• and
• apply a stochastic gradient adaptive filter to the output signal to:
• equalize a second amplitude associated the second signal received by the second receiver with a first amplitude associated with the first signal received by the first receiver;
• and
• equalize a second delay associated with the second signal received by the second receiver with a first delay associated with the first signal received by the first receiver.

A transmitter for underwater acoustic full-duplex communication, the transmitter comprising:

• a transmitter array comprising a first transmitter and a second transmitter, wherein the first transmitter and the second transmitter are:
• positioned along an axis of a radiation pattern maximum;
• separated by a distance approximately equal to a half wavelength of a central frequency of the working frequency band;
• and
• configured to transmit waveforms with opposite polarity to at least one receiver positioned in a plane perpendicular to the axis such that the waveforms interfere to produce near-zero sound pressure in the plane.

A system for underwater acoustic full-duplex communication, the system comprising:

• an adaptive processor configured to:
• receive an output signal from a receiver positioned on an axis extending through a center of a first transmitter and a center of a second transmitter positioned along the axis, wherein the first transmitter and the second transmitter are separated by a distance approximately equal to a quarter wavelength of a central frequency of the working frequency band;
• and
• apply a stochastic gradient adaptive filter to the output signal to:
• equalize a first amplitude of a first signal having a first polarity transmitted by the first transmitter with a second amplitude of a second signal having a second polarity opposite the first polarity transmitted by the second transmitter;
• and
• equalize a first delay of the first signal with a second delay of the second signal.

A receiver for underwater acoustic full-duplex communication, the receiver comprising:

• a receiver array, comprising:
• a first receiver set comprising a first receiver and a second receiver, wherein the first receiver and the second receiver are:
• separated by a distance approximately equal to a half wavelength of a central frequency of the working frequency band;
• symmetrically positioned along a first axis an equal distance from a transmitter;
• connected in parallel in an opposite polarity;
• and
• configured to:
• output a near-zero signal in response to a signal transmitted by the transmitter;
• and
• output a non-zero signal in response to any signal arriving from a direction different than orthogonal to the first axis;
• and
• a second receiver set comprising a third receiver and a fourth receiver, wherein the third receiver and the fourth receiver are:
• separated by the distance approximately equal to the half wavelength of the central frequency of the working frequency band;
• symmetrically positioned along a second axis an equal distance from the transmitter, wherein the second axis is perpendicular to the first axis;
• connected in parallel in an opposite polarity;
• and
• configured to:
• output a near-zero signal in response to the signal transmitted by the transmitter;
• and
• output a non-zero signal in response to any signal arriving from a direction different than orthogonal to the second axis.

A system for underwater acoustic full-duplex communication, the system comprising:

• an adaptive processor configured to:
• receive an output signal from a second receiver, wherein a first receiver and the second receiver are positioned along an axis extending through a center of the first receiver and a center of the second receiver, and wherein the first receiver and the second receiver are separated by a distance approximately equal to a quarter wavelength of a central frequency of the working frequency band;
• and
• apply a stochastic gradient adaptive filter to the output signal to:
• equalize a second amplitude associated with a second signal received by the second receiver from a transmitter positioned on the axis with a first amplitude associated with a first signal received by the first receiver from the transmitter;
• and equalize a second delay associated with the second signal received by the second receiver from the transmitter with a first delay associated with the first signal received by the first receiver from the transmitter.