The UAN project aims at conceiving, developing and testing at sea an innovative and operational concept for integrating in a unique system submerged, surface and aerial sensors with the objective of protecting critical infrastructures, such as off-shore platforms and energy plants. The security of such economically vital infrastructures requires an integrated approach involving underwater and land/air sensors and actuators for surveillance, monitoring and deterrence. In particular UAN focuses on a security oriented underwater wireless network infrastructure, realized by hydroacoustic communication. The UAN concept is to gather environmental information during the acoustic transmission and use it to predict the acoustic propagation conditions and the optimal obtainable performance at any given time. This information is used in the communication system for precise tuning. This tuning will take place at two different levels: i) by improving the basic point-to-point connection, by introducing physical and geometric constraints in the channel equalization and optimization process of the communication settings and ii) at the macro network configuration level by adapting node geometric configuration to the acoustic propagation conditions predicted from the environmental observations. This can be done in depth or in range by moving nodes placed on AUVs either to increase the point-to-point communication capacity or by serving as relay nodes to more distant, and at that time, inaccessible fixed nodes. This is a rather new approach that requires a better understanding of the acoustic propagation physics as well as a capacity to include that knowledge into technologically advanced communications modules and algorithms for underwater communications. The UAN project builds on a multidisciplinary consortium of technologically advanced industries, field experienced university labs and governmental agencies, thus grouping the required knowledge and experience.