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In underwater acoustic sensor networks (UASNs), the sensors are deployed at different areas of the ocean, which perform information collection and delay-sensitive routing to the data center for further processing or industrial computing. However, in UASNs, the network states have spatiotemporal characteristics due to tides or autonomous underwater vehicles. To steadily route the traffic especially when the spatiotemporal characteristics of the UASNs are considered, a network architecture with intelligent traffic engineering or routing policies is indispensable. In this paper, we employ software-defined networking (SDN) technology and propose an SDN-enabled distributed architecture for UASNs. Based on the proposed architecture, we propose a scheme DSR-SDN for delay-sensitive spatiotemporal routing in SDN-enabled UASNs. The DSR-SDN includes three phases: First, topology awareness; second, spatiotemporal characteristics estimation; and third, routing computation. Particularly, with SDN features, DSR-SDN provides topology awareness based on a proposed software-defined beaconing scheme. Based on the detected topology, the spatiotemporal characteristics of the network states are estimated based on a proposed SDN-based hierarchical node localizing approach SDN-HL. Lead by the SDN controllers, SDN-HL makes use of the proposed “minimum weighted gap” formulation and Adam algorithm to optimize the localization and builds the indirect links to increase the localization rate. To route the traffic through the network with spatiotemporal characteristics, we adopt the time-expanded network approach, based on which a spatiotemporal route decision can be made before the routing starts. The simulation results demonstrate that the proposed scheme, i.e., DSR-SDN, can conduct accurate spatiotemporal characteristic estimation for the network states and provide delay-sensitive spatiotemporal routing for the sensed data. [ABSTRACT FROM AUTHOR]

High-quality CPNT is a key technology for deep-sea vehicles that dive into the deep sea and for detecting and developing the deep sea. At present, however, CPNT services for deep-sea vehicles are provided by separate communication, positioning, and navigation systems as well as separate synchronous clocks (atomic clocks). This directly affects the operational efficiency, for example, update rates of up to 0.125 Hz, of deep-sea vehicles engaged in deep-sea scientific research, environmental investigation, and resource development. Therefore, a new design method and operating mode of CPNT is proposed herein to overcome the inherent flaws of the current communication/positioning/navigation modes of deep-sea vehicles; meet the actual demands of deep-sea vehicles in real time; achieve high update rates, low power consumption, and high precision positioning and navigation; and to be combined with the current development trends. The integration of CPNT can both unify time and space references, and reduce the difficulty of multi-sensor information fusion. Thus, the problems of poor navigation and the non-timing functions of deep-sea vehicles can be solved fundamentally. The integration of CPNT will improve the navigation and positioning accuracy as well as the information update rate (up to 1 Hz) of large deep-sea vehicles, such as deepsea human-occupied vehicles, deep-sea remotely operated underwater vehicles, and deep-sea autonomous underwater vehicles. [ABSTRACT FROM AUTHOR]