US Patent 9641262 Method and apparatus for underwater acoustic communication

Systems and methods are disclosed allowing for spatially separated nodes to transmit data to a single remote master receiver node in a synchronized way. Slave nodes can send acoustic data so that it travels through water and arrives at the master node exactly timed so that the data bit appears in a predetermined time slot. The next time slot could be a data bit coming from another remote or slave node in another direction and at a different distance. This can be repeated for many nodes and the incoming bits will be received in a time division multiplexed fashion at the receiver or master node. The senders address and bit meaning are implicit due to the time slot in which they arrive. The assumption is that all nodes have accurate synchronized time as well as the ability to accurately estimate sound travel time between itself and any master node.