Abstract—In the future communication applications, users may obtain their messages that have different importance levels distributively from several available sources, such as distributed storage or even devices belonging to other users. This scenario is the best modeled by the multilevel diversity coding systems (MDCS). To achieve perfect (information-theoretic) secrecy against wiretap channels, this paper investigates the fundamental limits on the secure rate region of the asymmetric MDCS (AMDCS), which include the symmetric case as a special case. Threshold perfect secrecy is added to the AMDCS model. The eavesdropper may have access to any one but not more than one subset of the channels but know nothing about the sources, as long as the size of the subset is not above the security level. The question of whether superposition (source separation) coding is optimal for such an AMDCS with threshold perfect secrecy is answered. A class of secure AMDCS (S-AMDCS) with an arbitrary number of encoders is solved, and it is shown that linear codes are optimal for this class of instances. However, in contrast with the secure symmetric MDCS, superposition is shown to be not optimal for S-AMDCS in general. In addition, necessary conditions on the existence of a secrecy key are determined as a design guideline.
标签： Fundamental Limits Secure Class on of
上传时间： 2020-01-04
上传用户：kddlas
PRODUCT DESCRIPTION The AD810 is a composite and HDTV compatible, current feedback, video operational amplifier, ideal for use in systems such as multimedia, digital tape recorders and video cameras. The 0.1 dB flatness specification at bandwidth of 30 MHz (G = +2) and the differential gain and phase of 0.02% and 0.04° (NTSC) make the AD810 ideal for any broadcast quality video system. All these specifications are under load conditions of 150 Ω (one 75 Ω back terminated cable). The AD810 is ideal for power sensitive applications such as video cameras, offering a low power supply current of 8.0 mA max. The disable feature reduces the power supply current to only 2.1 mA, while the amplifier is not in use, to conserve power. Furthermore the AD810 is specified over a power supply range of ±5 V to ±15 V.
上传时间： 2020-04-19
上传用户：su1254
This book has grown out of my teaching and research at the University of Surrey and out of my previous experiences in companies such as Philips, Ascom and Motorola. It is primarily intended for use by students in master’s level and enhanced final-year under- graduate courses who are specialising in communication systems and wish to understand the principles and current practices of the wireless communication channel, including both antenna and propagation aspects
标签： Propagation Antennas
上传时间： 2020-05-26
上传用户：shancjb
The current methods of communications are becoming less relevant under today’s growing demand for and reliance on constant connectivity. Of decreasing relevance are the models of a single radio to perform a single task. The expansion of wireless access points among coffee shops, airports, malls, and other public arenas is opening up opportunities for new services and applications.
上传时间： 2020-05-26
上传用户：shancjb
The aim of this book, the first of two volumes, is to present selected research that has been undertaken under COST Action IC0902 ‘‘Cognitive Radio and Net- working for Cooperative Coexistence of Heterogeneous Wireless Networks’’ (http://newyork.ing.uniroma1.it/IC0902/). COST (European Cooperation in Sci- ence and Technology) is one of the longest-running European frameworks sup- porting cooperation among scientists and researchers across Europe.
上传时间： 2020-05-26
上传用户：shancjb
A series of features makes the mobile telecommunications industry an interesting field of investigation for economists: the industry is experi- encing veryfastmarketgrowthcombinedwithrapidtechnological change; regulatory design in setting market structure is playing a very important role; and oligopolistic competition is unfolding under various forms. The number of subscribers to mobile networks is growing at a rapid rate on a worldwide basis, as shown in figure 1.1.
标签： Telecommunications Economics Mobile of
上传时间： 2020-05-27
上传用户：shancjb
Fundamentals of WiMAX was consciously written to appeal to a broad audience, and to be of value to anyone who is interested in the IEEE 802.16e standards or wireless broadband networks more generally. The book contains cutting-edge tutorials on the technical and theoretical under- pinnings to WiMAX that are not available anywhere else, while also providing high-level over- views that will be informative to the casual reader.
标签： Understanding Fundamentals WiMAX of
上传时间： 2020-05-27
上传用户：shancjb
One of the very first books published on the social impact of the mobile phone was Timo Kopomaa’s The City in Your Pocket: Birth of the Mobile Information Society. The book, published in 2000, was based on research that Kopomaa had under- taken for Nokia and Sonera as part of his doctoral studies in the Centre for Urban and Regional Studies at the Helsinki University of Technology. The first line he writes in the book is peculiar: ‘Mobile communication is not a serious matter’. By this, we assume he is referring to a view of the world that would regard the mobile phone as little more than an unremarkable fact of everyday life – a simple play- thing for the young, or a productivity tool for the business executive and busy parent.
标签： Communications Wireless Mobile and
上传时间： 2020-05-30
上传用户：shancjb
European Research Framework programs are public policy instruments designed to strengthen European competitiveness through cooperation. Although they have a fixed time frame, determined research themes, and a specific expected impact, the achievements in research and development (R&D) made by these funded proj- ects pave the way for a research continuum.
标签： Communications Horizons Wireless Mobile New and in
上传时间： 2020-05-31
上传用户：shancjb
European Research Framework Programs are a public policy instrument to strengthen European competitiveness through cooperation. Although they have a fixed timeframe, determined research themes, and specific expected impact, the achievements in research and development (R&D) made by the funded projects pave the way for a research continuum.
标签： New Horizons Mobile Wireless
上传时间： 2020-05-31
上传用户：shancjb
