非常规突发事件下应急通信预案体系有效性评估研究

非常规突发事件下,应急通信是实施指挥调度和保障信息传递的关键,其重要的前提和基础是应急通信预案体系的合理、有效。基于此,本文在对国内外应急通信预案体系做大量理论和实践调研的基础上,科学界定“有效性”内涵,从预案体系“效率”和“效果”两个维度切入对其进行研究,为应急通信预案“有效性”的评估提供相应的参考,为政府相关部门制定应急管理政策提供决策依据。     

光载波频分多路和微波副载波频分多路光纤通信系统

本文说明光纤通信有两类很重要的频分多路(FDM)技术,第一类是由少数几路光载波的波分多路(WDM)过渡至几十、几百路光载波密集频分多路系统,这是光的 FDM,主要用于数字通信。第二类是在微波式甚高频范围内几路、几十路副载波组合为电的 FDM 信号。对一个光的主载波调制,成为副载波频分多路系统(SCM)既用于数字通信,也用于光纤有线电视(CATV)的几路、几十路模拟电视广播。     

Performance Evaluation of Distributed Database Architectures for UMTS Service Deployed in an Urban Area

The design of distributed databases (DDBs) destined to store user information is a key issue in third-generation mobile communication systems such as UMTS. In particular, the problem of determining the most appropriate DDB architectures for UMTS is critical due to the anticipated requirements of high distribution and adaptability of information. This paper presents a model which allows different DDB architectures to be evaluated, in terms of query loads and average search times. The model proposed puts no constraints on either the DDB structure arrangement or the user position characterization. The paper also discusses a real, significant case study, concerning a query operation arising from an access procedure performed on the DDB of a communication network covering an urban area.     

半导体激光器与新材料

介绍了半导体激光器和半导体光电材料研究的新进展。     

迅速崛起的亚太光纤市场

本文归纳分析出亚太光纤市场的两个显著特点，介绍了亚太地区光通信发展水平，以及亚太各国和地区间的光通信合作，指出亚太光纤市场得以迅速发展的主要原因。     

F—PORT传真存储转发系统

本文介绍了日本ＫＤＤ公司的Ｆ－ＰＯＲＴ传真存储转发系统的构成、工作方式及其功能。     

Location-Independent Access in Mobile Systems

In this paper, we report on the design of a protocol for transparent, location-independent access in mobile systems. The protocol, termed by us Mobile Client/Server Protocol (MCSP) is an implementation of a communication layer on a mobile host and a stationary machine within the wireline network, and provides middleware functionality. The MCSP supports communication services through the client/server paradigm to transaction-oriented applications distributed between the mobile and a set of service and information brokers. To support the mobile and the wireless environment, a surrogate process is created within the fixed network to perform operations on behalf of the mobile within the fixed network. The MCSP then loosely couples the communicating entities, thus reducing the overhead associated with handoffs and disconnects, so characteristic of the mobile environment. Of particular interest is the application of the MCSP to location-based services, for example, the Intelligent Vehicle Highway Systems [1].     

Satellites for communications and broadcasting: The evolving european market

The paper traces the development of the market for communications and direct broadcasting satellites in Europe, since the original specification of the European Communications Satellite (ECS) in 1977. It reviews the experiments undertaken on the Orbital Test Satellite (OTS) and the way in which demonstrations with this satellite have influenced the way in which ECS is being developed. It continues by considering the impact of television on the market, first cable television and its distribution requirements, then direct broadcasting by satellite, where the introduction of homes into the customer configuration will bring with it programme content as a salient feature in market development. Finally it speculates on the possibilities for the future, both in terms of the effect of new and higher frequencies on satellite communications systems, and the possible effects that interaction from small earth-stations could have on satellite design.     

High Altitude Platform Station (HAPS): A Review of New Infrastructure Development for Future Wireless Communications

This paper looks into the relatively new field of high altitude platform stations. HAPS is seen as a ‘middle ground’ between the terrestrial and satellite cases, and aims to exploit of the advantages of both types of system. Since HAPS is such a new field, this paper focuses on the technology behind a HAPS communications system, how this has developed, and compares it to the terrestrial and satellite equivalents. One important area that is being investigated is the applications for which HAPS should be used. This is a critical issue if a significant business case is to be made for HAPS. Worldwide HAPS projects and research issues are also highlighted. Finally, the review concludes with the remarks on the future of HAPS for wireless communications systems.     

通信系统交流不间断供电的设计探讨

重点介绍了由目前在通信系统中大量使用的UPS引发的一系列问题,探讨一种可靠、实用的不间断供电的实现办法;从而满足现代通信技术日益发展的需要,真正实现网络系统的不间断,为广大网络设计人员提供另外一种选择。