A communication system comprising a communication unit having a local wireless communication mechanism, a remote wireless communication mechanism, a processor, and a power supply; and, at least one of a sensor unit having a sensor mechanism, a local wireless communication mechanism and a power supply. Each of the communication unit and at least one sensor unit is provided in a discreet housing and can be arranged proximal to each other unit to form a cluster. Each local wireless communication mechanism can communicate data to each other local wireless communication mechanism within the cluster. The communication unit remote wireless communication mechanism is operable to communicate outwith the cluster.

A communication system comprising a communication unit having a local wireless communication mechanism, a remote wireless communication mechanism, a processor, and a power supply; and, at least one of a sensor unit having a sensor mechanism, a local wireless communication mechanism and a power supply. Each of the communication unit and at least one sensor unit is provided in a discreet housing and can be arranged proximal to each other unit to form a cluster. Each local wireless communication mechanism can communicate data to each other local wireless communication mechanism within the cluster. The communication unit remote wireless communication mechanism is operable to communicate outwith the cluster.

An optical underwater communication system is disclosed which includes a first transceiver and a second transceiver, each including one or more optical sources configured to provide light activated and deactivated according to a first bit stream, one or more sensor packages each comprising a plurality of photodetectors configured to receive light from the other transceiver and, in response, provide an output voltage signal and an output current signal, a detector configured to i) convert the output voltage signal and the output current signal to pulses associated with arrival of photons, and ii) count the number of pulses based on a predetermined timing sequence, an encoder configured to encode a message to be sent into a first bit stream, and a decoder configured to decode a message received into a second bit stream.

The present disclosure may be embodied as a transmitter for multiuser multicarrier-chirp-division-multiplexing (“MU-MCDM”) communications. The present disclosure may be embodied as a receive for MU-MCDM communications. The present disclosure may also be embodied as a method for transmitting an MU-MCDM communication signal. The present disclosure may also be embodied as a method for receiving an MU-MCDM communication signal.

A communication system includes a first communication gateway arranged proximate to a surface of a body of water and an underwater communication gateway. The underwater communication gateway is configured to receive data from a first underwater communication device using radio frequencies and the ethernet data link layer protocol, to convert the data received from the first underwater communication device from the ethernet data link layer protocol to the second data link layer protocol, and to transmit, using optical radiation and the second data link layer protocol, the data converted by the underwater communication gateway to the first communication gateway. The first communication gateway is configured to convert the data transmitted by the underwater communication gateway from the second data link layer protocol to the ethernet data link layer protocol, and to transmit, using the ethernet data link layer protocol, the data converted by the first communication device to a further communication device.

A communication system includes a first communication gateway arranged proximate to a surface of a body of water and an underwater communication gateway. The underwater communication gateway is configured to receive data from a first underwater communication device using radio frequencies and the ethernet data link layer protocol, to convert the data received from the first underwater communication device from the ethernet data link layer protocol to the second data link layer protocol, and to transmit, using optical radiation and the second data link layer protocol, the data converted by the underwater communication gateway to the first communication gateway. The first communication gateway is configured to convert the data transmitted by the underwater communication gateway from the second data link layer protocol to the ethernet data link layer protocol, and to transmit, using the ethernet data link layer protocol, the data converted by the first communication device to a further communication device.

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.

An ultra-low or very low frequency communication device composed of: a circuit unit operative to produce an alternating current; and a dipole antenna connected to receive the alternating current and to convert the alternating current into electromagnetic radiation. The antenna is composed of an unshielded radiating conductor and a shielded return conductor connected in series with the radiating conductor, and the return conductor is shielded by a Faraday shield such as a collisionless plasma column that surrounds the return conductor to prevent any electromagnetic radiation from the return conductor.

According to the present embodiment, a hydraulic device measurement apparatus comprises a first wireless communication portion, and a second wireless communication portion. A transmitter and a receiver of the first wireless communication portion are arranged along the rotation axis of the rotating portion, and a transmitter and a receiver of the second wireless communication portion are arranged in the air along the rotation axis. The first wireless communication portion and the second wireless communication portion transmit and receive the transfer signal along the rotation axis of the rotating portion.