Keywords: acousticc communicationss coherentt equalizationn channel estimationn multi-pathh diversity c o m biningg beamformingg multiuser detectionn underwater data networkss sparse equalizationn blind equalizationn multirate adaptive lteringg cyclostationary statistics .

For decades, underwater acoustic communication has been restricted to the point-to-point long distance applications such as deep sea probes and offshore oil fields. For this reason, previous acoustic modems were typically characterized by high data rates and long working ranges at the expense of large size and high power consumption. Recently, as the need for underwater wireless sensor networks...

Recent technological improvements and application opportunities have fueled increased interest in the development and deployment of underwater acoustic sensor networks. Deployment efforts have been impeded by the prohibitive monetary cost and high power consumption of existing acoustic hardware. Alternately, we propose underwater networks that rely on widely available speakers and microphones i...

In this chapter, we focus on acoustic underwater networks, which utilize acoustic communication links to communicate between the nodes. It is wellknown that RF signals do not propagate well underwater, and the optical signals [1] are useful for short distances and under clear water propagation conditions. For long distances, the Navy has utilized acoustic communication. More recently, there has...

Underwater wireless technologies demand to transmit at higher data rate for ocean exploration. Currently, large coverage is achieved by acoustic sensor networks with low data rate, high cost, high latency, high power consumption, and negative impact on marine mammals. Meanwhile, optical communication for underwater networks has the advantage of the higher data rate albeit for limited communicat...

As the main way of underwater wireless communication, underwater acoustic communication is one of the focuses of ocean research. Compared with the free space wireless communication channel, the underwater acoustic channel suffers from more severe multipath effect, the less available bandwidth and the even complex noise. The underwater acoustic channel is one of the most complicated wireless com...

For telecommunication, radio waves are used in the air, whereas acoustic waves are used in underwater using transducers and hydrophones. And the underwater acoustic communication channels are very complicated than in the air, because of vertical distribution of acoustic velocity according depths, and reflections from boundaries like as surface or bottom, and etc. For the implementation of the u...

Wireless Sensor Networks (WSNs) caused a shift in the way things are monitored. While traditional monitoring was coarse-grained and offline, using WSNs allows fine-grained and real-time monitoring. While radio-based WSNs are growing out of the stage of research to commercialization and widespread adoption, commercial underwater monitoring is still in the stage of coarse-grained and offline moni...