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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]

With the remarkable advances in wireless communications and mobile electronic technologies, traveling users have been demanding continuous and seamless Internet access to enjoy multimedia services such as video streaming, voice over IP, online gaming, and so on, through handheld smart devices. Providing ubiquitous wireless connectivity to mobile users is indispensable to support continuous online services when vehicles move across various kinds of access networks. However, the high vehicle velocity and complex user mobility in the urban environment impose great challenges on designing an efficient mobility management scheme. In this article, we study the packet loss issue in IP mobility support for vehicular networks. We first give detailed descriptions of some major mobility management solutions. Then, we analyze user mobility models in the urban environment and identify the packet loss issue when traveling users roam across various access networks. By flexibly utilizing tunneling and buffering technologies, we correspondingly design a comprehensive solution to eliminate packet loss in each handover scenario of the urban environment. Finally, performance comparisons between the proposed scheme and related proposals have been conducted, which demonstrate a noteworthy potential of the presented scheme in eliminating packet loss and improving handover performance in urban vehicular communications. [ABSTRACT FROM AUTHOR]

A space and terrestrial integrated network (STIN) converges satellite communication networks, mobile wireless networking, and the Internet, has greatly extended the scope of cyberspace. The STIN is composed of diverse network elements and supports various access technologies, and the coordinations in the hybrid networks can better support complex and changeable communication tasks. Furthermore, the STIN takes advantage of the merits of low delay and large bandwidth in terrestrial networks, and achieves global coverage without the limitation of geographic conditions, which can support positioning and navigation, emergency relief, space exploration, and so on. However, the research on STIN is still confronted with some fundamental challenges including time-varying network topology, high satellite mobility, large end-to-end delay, scalability, and so on. In this article, we present a composite architecture that integrates space and terrestrial network components for providing anytime anywhere communications by utilizing the software defined networking and mobile edge computing paradigms, which not only facilitates the network management and increases network flexibility, but also provides improved quality of service for global multimedia services. Additionally, we identify a number of challenging issues associated with the proposed STIN architecture, including mobility management, resource management, routing, traffic steering, security, and so on, a [ABSTRACT FROM AUTHOR]

A space and terrestrial integrated network (STIN) converges satellite communication networks, mobile wireless networking, and the Internet, has greatly extended the scope of cyberspace. The STIN is composed of diverse network elements and supports various access technologies, and the coordinations in the hybrid networks can better support complex and changeable communication tasks. Furthermore, the STIN takes advantage of the merits of low delay and large bandwidth in terrestrial networks, and achieves global coverage without the limitation of geographic conditions, which can support positioning and navigation, emergency relief, space exploration, and so on. However, the research on STIN is still confronted with some fundamental challenges including time-varying network topology, high satellite mobility, large end-to-end delay, scalability, and so on. In this article, we present a composite architecture that integrates space and terrestrial network components for providing anytime anywhere communications by utilizing the software defined networking and mobile edge computing paradigms, which not only facilitates the network management and increases network flexibility, but also provides improved quality of service for global multimedia services. Additionally, we identify a number of challenging issues associated with the proposed STIN architecture, including mobility management, resource management, routing, traffic steering, security, and so on, a [ABSTRACT FROM AUTHOR]