Perspectives on national cable policy: Focusing the issues

Debate over the nature and desirability of a national cable policy for the United States has gained increased attention with U.S. Senate passage of cable legislation in 1983. This article delineates the developing positions and issues of this debate by an analysis of testimony before Congress. Where possible, various positions of this debate are illuminated by data drawn from cable literature, government documents, and a survey of American local governments conducted by the National League of Cities. This analysis highlights the degree to which the debate over cable policy reflects fundamental differences of opinion over the proper role and scope of government in American business generally and communications in particular.     

Bounds on maximum throughput for digital communications withfinite-precision and amplitude constraints

The problem of finding the maximum achievable data rate over a linear time-invariant channel is considered under constraints different from those typically assumed. The limiting factor is taken to be the accuracy with which the receiver can measure the channel output. More precisely, the following problem is considered. Given a channel with known impulse response h(t), a transmitter with an output amplitude constraint, and a receiver that can distinguish between two signals only if they are separated in amplitude at some time t ₀ by at least some small positive constant d, what is the maximum number of messages, N_max, that can be transmitted in a given time interval [0,T]? Lower bounds on N_max can be easily computed by constructing a particular set of inputs to the channel. The main result is an upper bound on N_max for arbitrary h(t). The upper bound depends on the spread of h(t), which is the maximum range of values the channel output may take at some time t₀>0 given that the output takes on a particular value α at time t=0. Numerical results are shown for different impulse responses, including two simulated telephone subscriber loop impulse responses     

Human resources development for communications in the Third World

This article summarizes Third World prospects for the development of human resources in communication programs. The discussion examines the structural causes of high demand for development of human resources. Also studied are pressures that stem from the dense populations in the regions, the cultural and linguistic diversity faced by their peoples, and the global media explosion. The shortage of suitable staff for communication programs has become chronic in most non-industrialized regions, making human resource development a high priority for media and other information services.     

解析移动通信频率资源的使用成本

在许可证制度下．许可证费将对移动服务和移动通信市场结构产生影响。对于我国3G许可证的发放．笔者建议采用评选或招标的发放程序合理评信频率资源的使用成本这样将更有利于信息通信业的开展。     

全国携号转网服务方案设计与政策研究

2019年政府工作报告提出“实现全国携号转网服务”。在实施携号转网过程中,现网改造、业务规则、行业监管等诸多方面都存在不同程度的挑战。首先,结合用户需求和行业规范,分别从业务交互和系统支撑两个层面提供了一整套服务实施方案,包括携号转网服务流程、发端查询机制等。其次,对携号转网政策进行了研究和分析,包括监管政策、携号转网用户画像、企业运营策略等,并提出优化建议。最后,对携号转网在未来通信市场发展趋势的影响进行了展望。目前,中国电信持续保持净携入,且携号转网投申诉率、系统故障率均保持行业最低,有关监管建议得到行业主管部门的初步采纳。     

Evolution of the communications industry in advanced countries: Implication for the policy direction of Korea

After the remarkable growth of the nation's communications industry during the 1980s, the Korean government has progressively introduced the competition principle to the service market. Facing the recent trend of market liberalization together with service globalization widely adopted in advanced countries, the government has now reached a turning point as regards redirecting its communications policy. This article aims to assist Korean policymakers in setting up a new policy direction. Conceptualizing the evolutionary process of the communications industry and grasping the future evolution in advanced countries will surely shed light on the path along which following countries such as Korea are going to move. Doing this work, we specifically emphasize the role of governments in following countries which is quite different from that of forerunners. With these discussions in the background, we suggest a new policy planning process for following countries and, further, go on to derive a technology-oriented globalized policy direction specifically tailored to the Korean communications industry.     

On optimal signal sets for digital communications with finiteprecision and amplitude constraints

The maximum data rate that can be reliably communicated given a linear, time-invariant, dispersive channel, a receiver that samples the channel output to within an accuracy of ±d where d >0, and a transmitter with an output amplitude constraint is evaluated. For any dispersive channel the maximum rate depends on d and is finite. The transmitted waveforms must be designed so that two channel outputs associated with two distinct transmitted signals are separated in amplitude at a particular time by d. It is shown that given any channel impulse response with rational Laplace transform, there exists an optimal sets of inputs that are ±A everywhere where A is the maximum allowable amplitude. Furthermore, in any finite time interval, each input changes sign a finite number of times. If the channel impulse response is a single decaying exponential, it is shown that simple binary signaling, in which A or -A, depending on the current message bit, is transmitted during each symbol interval, maximizes the data rate     

Regulatory and policy issues protecting public safety with better communications systems

The communications failure present in the September 11 World Trade Center tragedy served as the basis for this paper. These communications failures are not the result of simple operator error or a single design flaw. The problems are rooted in the basic technical architecture of the communications infrastructure used for public safety in the United States, and the policy that produced that infrastructure. This paper presents innovation in both technology and policy to address the many problems.     

A multielement array antenna with additional constraints on the radiation pattern for operation in wireless communications systems

An algorithm for neutralization of the multipath-propagation effect with substantial angular spread is proposed. This algorithm is more stable than similar classical algorithms. Additional stability is attained owing to the use of artificial constraints that allow formation of wide nulls in the direction of interferences and wide maxima in the direction of the desired signal. The null width can be changed via selection of the order of the imposed constraints. The complexity of the hardware implementation of such a system can be decreased because requirements for the accuracy of estimated values of angular coordinates become less stringent.     

Universal personal communications: Emergence of a paradigm shift in the communications industry

It is postulated that today we are in the midst of a major paradigm shift in the communications industry. The essence of this paradigm shift is a transition from today's universal telephone service which has been perfected over the past 100 years, to a future communication service environment, referred to as universal personal communication. Under this new paradigm, communications will be person based in contrast to the predominantly location-based communication environment of today. Societal trends, evolving global standards for communication, regulatory policies, and emergent technologies are seen as the forces driving such a transition. Universal personal communications will be characterized by flexible access to universal services permittingmore enduser control which will result in personalization and customization of such services. Furthermore, the centralized intelligence focus of today's communication networks needs to evolve toward a focus where network intelligence can be migrated to the periphery of the core transport network. The viability of universal personal communication will be critically dependent upon how well it addresses the end customer value proposition. Two key elements of this proposition are transparency of mobility and personalization of service environments. A zonal service environment model which classifies and characterizes these various service environments in terms of common communication parameters is proposed. This model is built around hierarchical structures for both cellular and digital wireless transmission, and can be viewed as critical towards the realization of transparent mobility management and personalization of services.     

International communications: the problems of progress

Many people think that the future of international communications lies only in the expansion and refinement of satellite facilities. However, cable and radio continue to play vital roles in the overall telecommunications picture. In the long run, the resultant mix of satellites, cables, and other forms of communication will be determined by what each form does best?and at what cost.     

Broadband communications: the commercial impact

The impact of broadband ISDN (integrated services digital network) is assessed. It is pointed out that the key step in its introduction, i.e. the replacement of the copper wire infrastructure by optical fiber, is already taking place. Two alternative routes for the introduction of broadband services are described: the market-driven route and the investment-led route. The market-driven route entails carriers responding to the demands currently being made of them. In the investment-led route, carriers lead the market and create demands by substantial investment in fiber residential networks. Carrier costs and rewards and anticipated market growth are examined. Broadband applications, the role of video communications, and the technology that will be used are briefly examined     

Office of telecommunications policy proposed biomedical telemetry standard for emergency medical communications march 1975

This standard defines the minimum requirements for a multiplex or nonmultiplex voice/telemetry channel to assure compatibility and interoperability of portable physiologic monitoring equipment with both radio and telephone equipments and hospital emergency and display devices. Specifically, it defines a National telemetry subcarrier frequency within the voice band which is compatible with both radio and telephone transmission characteristics. This standard applies only to voice and telemetry modulation-demodulation electronic instrumentation used in emergency medical care.     

Standardization on multimedia communications:computer-telephony-integration-related issues

Computer-telephony integration (CTI) has been developed since the 1960s. It is one of the major emerging multimedia communications applications. It provides enhanced telecommunications services controlled by a computer, that is by integrating the call handling capabilities of PBXs and the data processing capabilities of computers. CTI applications have become more popular and widespread with the rapid and deep penetration of personal computers and the dramatic growth of the Internet since the mid-1990s. CTI applications are being enhanced by means of more integration with Internet capabilities. Several standardization organizations and fora/consortia are developing standards/specifications for CTI in order to cope with the growing demand for multimedia communications. This article describes a brief historical sketch and the state of the art of CTI-related standards and specifications, which are still being developed     

移动IP 切换时资源分配动态策略生成机制研究

针对多媒体业务在切换后无法立即获得有保证服务的问题,提出一种移动IP切换时资源管理的动态策略模型,并着重设计模型中动态策略的生成机制。该机制根据移动节点相关预测信息自动生成动态策略,在切换前作准入控制和资源准备。当接入域资源不足时,采用“退却”算法,在保证业务可靠性前提下按优先级灵活调整各业务的资源占有量。分析和仿真表明,该机制能保证较高优先级业务的QoS,提高切换成功率,相对于传统方法更灵活。     

超宽带通信技术及其在军事通信方面的应用

本文给出了超宽带(Ultra-wide Bandwidth:UWB)系统的信号表示形式,分析了其具体含义、信号特点及UWB通信系统的性能,结合当前军事通信的特点及发展趋势,介绍了超宽带脉冲通信在军事通信领域的应用现状及前景。     

European mobile communications on the move

A brief summary of the main activities performed under the RACE program in the field of mobile communications is presented, In particular, the technological studies and development have been outlined, showing that work has significantly progressed with major systems performance results already available from the various testbeds developed and coordinated by the projects. In parallel, possible evolution paths from second to third generation systems have been presented, together with regulatory trends, Beyond the technological work performed under the RACE program, it is hoped that the new ACTS program will further the progress in developing wireless technologies while paying progressively growing attention to the development of a strategic vision of mobile and personal communications beyond the year 2000. Finally, a brief presentation of the ACTS program has shown that the coming years should be devoted to services validation through active user involvement in field trials. The results are expected to he of great use to potential operators, providing them the possibility of testing user acceptance of broadband mobile services. Future mobile communications systems will need to provide users with broadband capabilities and advanced services, allowing for seamless provision across fixed and mobile networks     

Effects of the ground on power-line communications

In this paper, a radiated-emission model of broad-band power-line communications (PLCs) in the frequency range from 1 to 30 MHz is presented. The model is based on the full-wave approach with the formulations of the extracted Maxwell equations. The transmission characteristic of the power line is obtained with the boundary conditions. The effects of the ground on the transmission characteristic and radiation are emphasized. Experiments were made to check the validity and accuracy of our model. It shows that the model is useful in predicting the effect of the ground on the radiation of straight PLCs.