全球移动通信发展趋势

新世纪初，在全球电信业普遍下滑的大环境下，移动通信仍继续增长。虽然增长速度比90年代要慢些，但是在新千年的头两年里，全球大约共新增移动电话5亿部，此数超过了截至2000年初移动电话销售的总数。这无疑给电信业注射了一支强心针。移动通信的发展总是超过了我们的预期。在     

业务迁移与选择多元化--全球无线通信发展趋势及宽带无线应用前景分析

过去十年中,全球移动通信走过了黄金年代.它不仅成为电信利润增长的最重要源泉,还从某种程度上改变了人们的通信方式,造就了一批风光无限的新兴电信企业.但是,应该看到,随着用户趋向饱和,无线通信正面临着新的挑战.其支柱业务移动电话在未来必然向移动数据业务迁移,但是这一过程相当缓慢,于是现实中各大公司ARPU(从每个用户中获得的平均收入)值不断下降,来自财务报表的预警信号不时让公司员工触目惊心.     

全球无线频率大拍卖

拍卖实际上是一种市场经济的产物,是国家对无线频率这一自然资源采用市场经济手段分配的方式。它具有公正、透明的特点,可以避免评审方式中出现的行业垄断或者腐败现象。随着3G脚步的临近,各大运营商对3G执照的争夺日趋激烈。而通过拍卖方式发放3G通信业务许可证被很多国家所青睐,英国、德国等欧洲国家第一次拍卖就为国库增加了几百亿美元的收入,着实让很多国家跃跃欲试,也开始研究这种方式对本国的适用性。频率使用许可证与经营许可证的关系众所周知,为公众提供通信业务需要得到国家电信主管部门批准,各国管制机构主要采用许可证…     

A new generation of global wireless compatibility

The expanding growth of wireless communications has led to the proliferation of different standards. The highly competitive market demands low-cost, low-power, and small form-factor devices. This calls for the development of a single-chip, third-generation (3G) receiver capable of adapting to the various communications standards in a low-cost CMOS technology. However, fully integrated receiver architectures require the elimination of discrete high-Q image rejection and IF filters. Thus, the received signal is down-converted to baseband without channel filtering, which most frequently results in the presence of strong adjacent channel blockers along with the desired signal. Therefore, it is required from the baseband filter design to exhibit a high-dynamic range, a programmable bandwidth to accommodate different standards, precise tuning to select the desired channel within a standard, low power, and a small chip area. This article discusses the 3G wireless systems with a focus on the design of a reconfigurable baseband chain that precedes the ADC of a multistandard fully integrated wireless receiver. The baseband chain is adapted to accommodate the GSM, IS-95, and wideband CDMA wireless standards     

THe callingSM network: A global wireless communication system

There is a very large demand for basic telephone service in developing nations, and remote parts of industrialized nations, which cannot be met by conventional wireline and cellular systems. This is the world' largest unserved market. We describe a system which uses recent advances in active phased arrays, fast-packet switching technology, adaptive routeing, and light spacecraft technology, in part based on the work of the Jet Propulsion Laboratory and on recently-declassified work done on the Strategic Defense Initiative, to make it possible to address this market with a global telephone network based on a large low-Earth-orbit constellation of identical satellites. A telephone utility can use such a network to provide the same modern basic and enhanced telephone services offered by telephone utilities in the urban centres of fully-industrialized nations. Economies of scale permit capital and operating costs per subscriber low enough to provide a service to all subscribers, regardless of location, at prices comparable to the same services in urban areas of industrialized nations, while generating operating profits great enough to attract the capital needed for its construction. The bandwidth needed to support the capacity needed to gain these economies of scale requires that the system use K_a-band frequencies. This choice of frequencies places unusual constraints on the network design, and in particular forces the use of a large number of satellites. Global demand for basic and enhanced telephone service is great enough to support at least three networks of the size described herein. The volume of advanced components, and services such as launch services, required to construct and replace these networks is sufficient to propel certain industries to market leadership positions in the early 21st Century.     

焦虑与探索--全球无线运营商现状面面观

美国无线运营商面临整合，西欧手机用户增长几近停滞，日本上演无线局域网“热点”争夺战；在3G商用服务总是层纱遮面的时候，MMS充当了未来的探路先锋；有人惊呼市场已经饱和，有人却做起了ARPU的文章……这一系列让人眼花缭乱的消息喜忧参半，挑战与机遇同样近在眉睫，无线业     

An Internet and wireless networking‐based water pipes web application for fault reporting

With the advancement of modern technologies such as smart cities, IoT, and e‐governments, people have to participate in their well‐being self‐governing and safe guard their key resources and critical infrastructures. To employ their efforts efficiently, many modern handy applications are created and solutions are proposed. Supported by the Ministry of Water, we designed and developed a free‐of‐charge web application (App.), easy to download from Google play store and operate using simple gadgets. Users can report water and sewage accidents fast and easy and at no cost. By merging Surveying and Geomatics Engineering with Information and Communication Technology (ICT) with Wireless communication, networking technology, and systems, we are able to create a web application to report complaints of accidents directly to the right delegated call centers at the Water Authority using the Internet and a smart mobile phone (simple gadgets). This will automate the complaint process and cancel the old paper work system. Surveying and Geomatics Engineering are concerned with the creation of an accurate GIS to manage the Water Authority data and in the data uploading into Google Maps. The developed computer program (application) works in two ways: first, it connects users (customer or employee) to the water authority electronically, and second, it allows immediate checking about the location of the complaint, momentarily filling using the Authority coordinate system, immediate action delegation (repair) at the water authority, continuous follow up, and confirmation to the user about the case. It performs as well, the needed coordinate transformation to guarantee exact filing and locations. Several software tools and programming languages are used to achieve this work such as ArcGIS, Google earth, Google map, GIS cloud, and Java and C++. As a case study, we present the App. performance for a town “Al‐Fuheis, Jordan” using the Water Authority data for creating the needed Water pipes and Sewage (GIS). Moreover, we presented the performance and the efficiency of the App. even when using Goggle Maps data only without GIS data intervention and it proved to be satisfying as well. As a result. a web App. called “Water Pipes” for the Water Authority is posted on their web to allow users participation in the reporting and the follow up process to better conserve the very scarce water in the country. In addition, it automates the work at the Water Authority from filing to take action and repair electronically in no time.     

The wireless revolution

Current demand for and recent developments in wireless communication are described. Funding for wireless worldwide is examined. Tools and techniques used to characterize radio propagation are discussed, and some research results are presented     

The illusion of web privacy

The author discusses how, for the ordinary netizen, it's surprisingly hard to be anonymous online.     

The wireless last mile

Phone companies losing broadband ground may have to embrace their enemy, wireless metropolitan-area networking itself about to take off now that a new standard, IEEE 802.16, has been adopted. Creating a wireless network is relatively simple. At its heart is a base station, which can be put on top of a building's roof, a cellular tower, or even a water tower. The base station is the bridge between the wired world of the Internet, on one end, and subscribers, with whom it is connected by radio waves, on the other. It largely takes the place of the DSL server in a phone company's central office With each station generally serving a 10- to 15-km radius, base stations can be put up where they're economically justified. The issues involved in the wireless last mile are discussed in this article.     

Real Voices in the Technological Wilderness Using ethnographic methods to challenge global wireless paradigms

This paper explores the use of ethnographic research to help companies design, build, and implement products and services that meet the stated and unstated needs of consumers. Although many products enjoy an international presence in the global economy, the market is far from homogeneous. Cultural practices and beliefs strongly influence the meaning and, consequently, the usage of products. If a product is not culturally resonant, the product may not be adopted by consumers - no matter how technologically advanced or innovative the product may be. Specifically, this paper explores mobile phone, and advanced network I-mode adoption in Japan. Research methodologies used in the case study are described, including how these techniques elucidate the various social and cultural processes that influence adoption. In order to develop wireless and other mobile communication solutions that are culturally, emotionally, and technically satisfying for users, the current “ global paradigm” must be reconsidered. Incorporating anthropology into the design process is a crucial first step in helping telecommunication companies define their next generation of products and services in the mobile communications arena.     

无线数传模块的应用

文中讲解了TXD1100无线数传模块的特点,详细介绍了利用该模块设计、开发了“主—被”工作模式下的控制系统方案.该系统具有自动识别无线数传模块的工作参数和在存在同频干扰的情况下能够自动跳频等优点.     

The FCC on personal wireless

In a landmark decision announced in September 1993, the Federal Communications Commission (FCC) outlined the rules to be followed in the United States by the up-and-coming personal communications services (PCS) industry. This industry is structuring itself to offer new mobile and portable wireless services in direct competition to those that already exist, such as paging, cellular, and private radio services. The FCC's decision was essential in paving the way. It allocated 160 MHz of radio spectrum, determined the size of the geographic service areas, and laid down eligibility requirements for the service providers. It also outlined broad technical standards and construction requirements, and established guidelines for evaluating the exposure of users to the radio-frequency (RF) radiation emitted by PCS devices. This action heralds auctions of the first licenses in 1994     

The capacity of wireless networks

When n identical randomly located nodes, each capable of transmitting at W bits per second and using a fixed range, form a wireless network, the throughput λ(n) obtainable by each node for a randomly chosen destination is Θ(W/√(nlogn)) bits per second under a noninterference protocol. If the nodes are optimally placed in a disk of unit area, traffic patterns are optimally assigned, and each transmission's range is optimally chosen, the bit-distance product that can be transported by the network per second is Θ(W√An) bit-meters per second. Thus even under optimal circumstances, the throughput is only Θ(W/√n) bits per second for each node for a destination nonvanishingly far away. Similar results also hold under an alternate physical model where a required signal-to-interference ratio is specified for successful receptions. Fundamentally, it is the need for every node all over the domain to share whatever portion of the channel it is utilizing with nodes in its local neighborhood that is the reason for the constriction in capacity. Splitting the channel into several subchannels does not change any of the results. Some implications may be worth considering by designers. Since the throughput furnished to each user diminishes to zero as the number of users is increased, perhaps networks connecting smaller numbers of users, or featuring connections mostly with nearby neighbors, may be more likely to be find acceptance     

大型企业网站安全系统解决方案

“传统企业是电子商务的主角”。在信息技术发展的时代,电子商务无疑为大型企业带来发展的巨大潜力。企业内外沟通、企业宣传、运营和企业内部管理都可通过建立企业网站来实现,从而为企业减少中间环节、规范管理、降低管理成本,提高企业效率。然而,如何保证网站信息传输的有效性、真实性、机密性和完整性,同时确保传输信息的不可抵赖性并提供审查能力,如何实现网上安全交易,正是众多大型企业网站建设迟疑或者驻足不前的主要原因之一。     

无线数传模块的应用

文中讲解了TXD1100无线数传模块的特点,详细介绍了利用该模块设计、开发了＂主—被＂工作模式下的控制系统方案。该系统具有自动识别无线数传模块的工作参数和在存在同频干扰的情况下能够自动跳频等优点。     

专题寄语:无线的动力

无线已成为当今信息产业不断前进的新动力,新的无线技术推动了电信网络的演进,新的业务形态改变了人们的信息获取形式,新的无线应用将信息化带到了百姓的身边.