Wireless communication has become an active part of our lives, but wireless communication under sea has not been in talk. Research is being going on various wireless technologies, but in the coming future aqua communication would be huge success. Huge progress could be witnessed in terrestrial sensor networks and a this will bring revolutinary change in the communication. The sensor basically consists of many battery-powered nodes which are deployed for close observation and for the well and long-term monitoring and autonomous underwater vehicles are being used for the continuous monitor. The information transfer between the sensor and AUVs make it challenging for the security. Achieving the communication between the sensors and the AUVs is difficult due to the movement of sensors with water currents. Development of reliable and efficient security is the main difference which make it apart from it's ground based counterpart. The primary application is seismic monitoring during pipeline construction, leak monitoring underwater etc. The underwater offer challenges to the design of data communication. The multi path reflections is one of them, beside this there is also curved propagation due to uneven temperature and different interferences, such as bubbles and man-made noises from objects.
Using of individual modems is quite expensive and also they consume more power, thus making it difficult to get hundred of modems economically infeasible. To overcome this difficulty complementary devices that benefit dense sensing and it is simple and numerous devices can be used with shorter range communication.
Talking about the goal of the overall design of the underwater modem is that to bring those characteristics which are being exploited in terrestrial sensor networks underwater. Long-range communication is already being achieved by multi-hop routing on individual nodes only need is the short-range communication. Focusing on short-range communication helps to overcome long-range difficulties and the target range is 50500m.Various techniques are used to get low power operation. Finally both analog and digital signal output from the modem for high synchronization can be achieved. The modem is divided into three parts a wakeup receiver, a data receiver, and a single transmitter. The single transmitter has three output frequencies which match with the data mark, data space, and wakeup tone.The circuit that is made it operates under 5 volt power supply (between 2.8 and 5 volts).
More research is being done under this aqua communication which will lead to better communication.