55,172 research outputs found
Mobility: a double-edged sword for HSPA networks
This paper presents an empirical study on the performance of mobile High Speed Packet Access (HSPA, a 3.5G cellular standard) networks in Hong Kong via extensive field tests. Our study, from the viewpoint of end users, covers virtually all possible mobile scenarios in urban areas, including subways, trains, off-shore ferries and city buses. We have confirmed that mobility has largely negative impacts on the performance of HSPA networks, as fast-changing wireless environment causes serious service deterioration or even interruption. Meanwhile our field experiment results have shown unexpected new findings and thereby exposed new features of the mobile HSPA networks, which contradict commonly held views. We surprisingly find out that mobility can improve fairness of bandwidth sharing among users and traffic flows. Also the triggering and final results of handoffs in mobile HSPA networks are unpredictable and often inappropriate, thus calling for fast reacting fallover mechanisms. We have conducted in-depth research to furnish detailed analysis and explanations to what we have observed. We conclude that mobility is a double-edged sword for HSPA networks. To the best of our knowledge, this is the first public report on a large scale empirical study on the performance of commercial mobile HSPA networks
Toward Universal Broadband in Rural Alaska
The TERRA-Southwest project is extending broadband service to 65 communities in the
Bristol Bay, Bethel and Yukon-Kuskokwim regions. A stimulus project funded by a combination
of grants and loans from the Rural Utilities Service (RUS), TERRA-Southwest has installed a
middle-mile network using optical fiber and terrestrial microwave. Last-mile service will be
through fixed wireless or interconnection with local telephone networks.
The State of Alaska, through its designee Connect Alaska, also received federal stimulus
funding from the National Telecommunications and Information Administration (NTIA) for tasks
that include support for an Alaska Broadband Task Force “to both formalize a strategic broadband
plan for the state of Alaska and coordinate broadband activities across relevant agencies and
organizations.”
Thus, a study of the impact of the TERRA project in southwest Alaska is both relevant and
timely. This first phase provides baseline data on current access to and use of ICTs and Internet
connectivity in rural Alaska, and some insights about perceived benefits and potential barriers to
adoption of broadband. It is also intended to provide guidance to the State Broadband Task Force
in determining how the extension of broadband throughout the state could contribute to education,
social services, and economic activities that would enhance Alaska’s future. Results of the
research could also be used proactively to develop strategies to encourage broadband adoption,
and to identify applications and support needed by users with limited ICT skills.Connect Alaska.
The National Telecommunications and Information Administration.
General Communications Incorporated.Part 1: An Analysis of Internet Use in Southwest Alaska / Introduction / Previous Studies / Current Connectivity / Analytical Framework and Research Methodology / Demographics / Mobile Phones: Access and Use / Access to the Internet / Internet Useage / Considerations about Internet Service / Interest in Broadband / Sources of News / Comparison with National Data / Internet Use by Businesses and Organizations / What Difference may Broadband make in the Region? / Conclusiongs / Part 2 Literature Review / Reference
Hybrid Satellite-Terrestrial Communication Networks for the Maritime Internet of Things: Key Technologies, Opportunities, and Challenges
With the rapid development of marine activities, there has been an increasing
number of maritime mobile terminals, as well as a growing demand for high-speed
and ultra-reliable maritime communications to keep them connected.
Traditionally, the maritime Internet of Things (IoT) is enabled by maritime
satellites. However, satellites are seriously restricted by their high latency
and relatively low data rate. As an alternative, shore & island-based base
stations (BSs) can be built to extend the coverage of terrestrial networks
using fourth-generation (4G), fifth-generation (5G), and beyond 5G services.
Unmanned aerial vehicles can also be exploited to serve as aerial maritime BSs.
Despite of all these approaches, there are still open issues for an efficient
maritime communication network (MCN). For example, due to the complicated
electromagnetic propagation environment, the limited geometrically available BS
sites, and rigorous service demands from mission-critical applications,
conventional communication and networking theories and methods should be
tailored for maritime scenarios. Towards this end, we provide a survey on the
demand for maritime communications, the state-of-the-art MCNs, and key
technologies for enhancing transmission efficiency, extending network coverage,
and provisioning maritime-specific services. Future challenges in developing an
environment-aware, service-driven, and integrated satellite-air-ground MCN to
be smart enough to utilize external auxiliary information, e.g., sea state and
atmosphere conditions, are also discussed
On-board processing satellite network architecture and control study
The market for telecommunications services needs to be segmented into user classes having similar transmission requirements and hence similar network architectures. Use of the following transmission architecture was considered: satellite switched TDMA; TDMA up, TDM down; scanning (hopping) beam TDMA; FDMA up, TDM down; satellite switched MF/TDMA; and switching Hub earth stations with double hop transmission. A candidate network architecture will be selected that: comprises multiple access subnetworks optimized for each user; interconnects the subnetworks by means of a baseband processor; and optimizes the marriage of interconnection and access techniques. An overall network control architecture will be provided that will serve the needs of the baseband and satellite switched RF interconnected subnetworks. The results of the studies shall be used to identify elements of network architecture and control that require the greatest degree of technology development to realize an operational system. This will be specified in terms of: requirements of the enabling technology; difference from the current available technology; and estimate of the development requirements needed to achieve an operational system. The results obtained for each of these tasks are presented
Leveraging Wireless Broadband to Improve Police Land Mobile Radio Programming: Estimating the Resource Impact
Despite rapid growth in criminological studies of police technology, examinations of police land mobile radios are absent in the literature. This is troubling given the central role mobile radios serve in police operations and their significant management costs. The present study seeks to fill this gap by introducing the functionality of wireless broadband radio programming. Current practice requires a police officer to physically drive to a radio programming location to manage their mobile radio. Wireless programming remedies this burdensome reality, thereby saving officer time and cost. Geospatial analyses are used to estimate distance saved associated with wireless programming. We then conduct a number of calculations to determine time and cost savings related to the observed differences between existing and wireless radio programming within the context of the North Carolina State Highway Patrol. Results suggest wireless radio programming can save significant personnel and financial resources. Implications are discussed
Wireless communication, identification and sensing technologies enabling integrated logistics: a study in the harbor environment
In the last decade, integrated logistics has become an important challenge in
the development of wireless communication, identification and sensing
technology, due to the growing complexity of logistics processes and the
increasing demand for adapting systems to new requirements. The advancement of
wireless technology provides a wide range of options for the maritime container
terminals. Electronic devices employed in container terminals reduce the manual
effort, facilitating timely information flow and enhancing control and quality
of service and decision made. In this paper, we examine the technology that can
be used to support integration in harbor's logistics. In the literature, most
systems have been developed to address specific needs of particular harbors,
but a systematic study is missing. The purpose is to provide an overview to the
reader about which technology of integrated logistics can be implemented and
what remains to be addressed in the future
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