A data encoding and decoding method for underwater acoustic networks (UANs) based on an improved online fountain code, including: in a build-up phase, subjecting all original packets to sequential encoding according to their serial numbers to generate and send encoded packets with degree 2; merging k original packets to k/8 connected components with a size of 8; performing random encoding until a largest connected component is successfully decoded; in a completion phase, sending, by a receiver, a feedback packet according to a current decoding graph; according to a feedback packet containing decoding states of all the original packets, sending, by a sender, encoded packets with degree m; and randomly selecting original packets for recursive encoding to generate and send encoded packets with degree 1 or 2; and setting, by the receiver, a threshold to restrict the number of feedback packets.

A data encoding and decoding method for underwater acoustic networks (UANs) based on an improved online fountain code, including: in a build-up phase, subjecting all original packets to sequential encoding according to their serial numbers to generate and send encoded packets with degree 2; merging k original packets to k/8 connected components with a size of 8; performing random encoding until a largest connected component is successfully decoded; in a completion phase, sending, by a receiver, a feedback packet according to a current decoding graph; according to a feedback packet containing decoding states of all the original packets, sending, by a sender, encoded packets with degree m; and randomly selecting original packets for recursive encoding to generate and send encoded packets with degree 1 or 2; and setting, by the receiver, a threshold to restrict the number of feedback packets.

An underwater communication method includes creating an air column in a water body using a device including a device body, an air column-generating component, and a transceiver, thereby forming an air column to a surface of the water body. A signal is transmitted, received, or a combination of transmitted and received using the transceiver through the air column to the surface of the water body.

An underwater communication method includes creating an air column in a water body using a device including a device body, an air column-generating component, and a transceiver, thereby forming an air column to a surface of the water body. A signal is transmitted, received, or a combination of transmitted and received using the transceiver through the air column to the surface of the water body.

A method for implementing a many-to-one concurrent transmission medium access control (MAC) protocol for underwater acoustic networks, including: initializing a network; setting a timer; initiating, by a receiving node, a control frame to perform handshakes with multiple nodes; exchange ID, level and location of the receiving node and a sending node, and counting the number of nodes that generate a sending notification (SN) message before timeout; and planning, by the receiving node, a receiving scheduling time of data from different nodes according to the number of successful handshake nodes, distance from each sending node to the receiving node, and data packet size; and performing data transmission.

A method for implementing a many-to-one concurrent transmission medium access control (MAC) protocol for underwater acoustic networks, including: initializing a network; setting a timer; initiating, by a receiving node, a control frame to perform handshakes with multiple nodes; exchange ID, level and location of the receiving node and a sending node, and counting the number of nodes that generate a sending notification (SN) message before timeout; and planning, by the receiving node, a receiving scheduling time of data from different nodes according to the number of successful handshake nodes, distance from each sending node to the receiving node, and data packet size; and performing data transmission.

A visual light communication system is disclosed.

A visual light communication system is disclosed.

This underwater optical wireless communication system (100) is provided with a plurality of moving bodies (1) capable of moving underwater. The plurality of moving bodies each includes a plurality of optical wireless communication units (2) each configured to perform bidirectional communication between the plurality of moving bodies using communication light beams (30) having wavelengths different from each other in a plurality of directions which are mutually opposite directions. The plurality of optical wireless communication units is configured to perform bidirectional communication between the plurality of moving bodies using communication light beams, the communication beams having the same wavelength with respect to each of the plurality of directions.

This underwater optical wireless communication system (100) is provided with a plurality of moving bodies (1) capable of moving underwater. The plurality of moving bodies each includes a plurality of optical wireless communication units (2) each configured to perform bidirectional communication between the plurality of moving bodies using communication light beams (30) having wavelengths different from each other in a plurality of directions which are mutually opposite directions. The plurality of optical wireless communication units is configured to perform bidirectional communication between the plurality of moving bodies using communication light beams, the communication beams having the same wavelength with respect to each of the plurality of directions.