Local measured telephone service in the USA: A quantitative analysis

The USA has steadfastly held to a flat rate for local telephone service, whereas most other countries are characterized by a user-sensitive (measured service) system of pricing. Economic theory suggests some method of measured service pricing more accurately reflects the true costs of local service. This article seeks to determine how many US consumers could be induced to switch to measured service pricing, and using ordinary least squares, derives a model of the demand for measured service. The factors are identified that will induce the US population to move towards a measured service rate structure. The findings indicate that consumers are quite responsive to both relative price (between a local flat rate and a measured service rate) and advertising.     

DS扩频信号数字解扩的工程实现途径

本文扼要概述直接序列扩频信号的解扩方法，着重介绍数字解扩的基本原理及其在工程上实现的途径，通过对模拟处理器件和数字处理器件的比较，指出数字处理器件具有很大的潜力和广阔的应用前景。     

小仰角下移动卫星通信性能的改善及仿真

移动卫星通信系统为功率受限系统,相对地面移动通信而言,其链路余量较小,而且由于多径及遮蔽效应,当系统工作在小仰角时,其信号衰落可达到30dB,这对系统的设计提出了严峻的挑战。本文研究了信道编码和交织技术在移动卫星通信系统中的应用。通过仿真,得到了应用该技术对不同仰角特别是小仰角条件下系统性能的改善程度。同时,在研究信道相关的基础上,给出了交织相关参数的设计准则。     

一种新型的基于神经网络的无线信道模型

本文提出了一种使用神经网络来建模和仿真无线通信信道的方法。由于神经网络优异的学习特性,文中使用神经网络对无线信道的输入输出响应进行建模,讨论了建模的方法,给出了仿真的结果,分析了遇到的问题和解决方法,并进一步阐述了在实际的无线信道环境中使用神经网络建模的优越性。     

移动商务身份认证评价体系的设计

移动商务身份认证机制的评价方法主要为安全性证明的形式化分析方法和单一指标比较的系统仿真方法,缺乏对认证机制性能的整体评价。移动商务身份认证评价体系必须满足移动商务身份认证的特点,即体现对移动商务特性及身份认证效果的检验。本文首先分析移动商务身份认证机制的应用现状和主要评价方法的不足,接着从安全性、适用性和成熟性设计移动商务身份认证评价体系的总体架构,最后逐层细化探讨了其各指标的选取。     

Regulation of international roaming in the European Union—Lessons learned

This paper analyzes the evolution of prices and competition in intra-EU international roaming markets. It addresses three main research questions: (i) to what extent have market forces by themselves brought competition to retail roaming markets? (ii) Has the evolution of market dynamics in wholesale roaming improved competition? (iii) Is wholesale regulation sufficient to lead to a reduction in retail roaming prices? Data show that there has been little price-based competition both at wholesale and retail levels, despite prices being well above costs and the significant margins allowed by regulation. Available data from the period preceding the entry into force of the first EU roaming regulation also point to the same conclusion. Lack of competitive pressure in retail roaming markets and inelastic demand give little incentives for retail roaming service providers to lower prices. Wholesale international roaming markets have complex competition dynamics. They are characterized by the reciprocity of wholesale roaming agreements and traffic internalization inside transnational groups. These circumstances limit price competition at the wholesale level. The traditional regulatory approach applied to electronic communication markets has been primarily focused on wholesale regulation. However, empirical evidence shows that even if wholesale charges are reduced, retail roaming markets continue to operate at very high retail margins (for example, more than 200% retail mark-up over wholesale charges for data roaming services and incoming calls). This proves that in international roaming markets wholesale charge reductions are not necessarily passed on to retail prices. It can thus be inferred that wholesale price regulation alone is in most cases not sufficient to ensure that benefits are passed through to end users.     

Regulation and competition in the European mobile communications industry: An examination of the implementation of mobile number portability

Over the past two decades, the mobile communications industry has seen a considerable drop in the consumer switching charges made by service providers in order to promote effective competition and ensure a level playing field for new market entrants. Mobile Number Portability (MNP) is an important regulatory measure taken to reduce switching costs, and it is believed to play an important role in fostering competition in the mobile market. MNP implementation has varied significantly across European Union countries, particularly with respect to porting time and customer fees, both of which are important factors when deciding whether to switch to another provider. The research examines the effects of MNP implementation on competition in the European mobile communications industry. The study findings indicate that subscriber churn rates are negatively affected by both the level of charges levied on subscribers wishing to maintain their current number (porting) when switching mobile providers and the length of time required to switch. The implications of the effectiveness of MNP regulation for competition in the mobile communications industry are discussed.     

Network effects and preference heterogeneity in the case of mobile telecommunications markets

This paper demonstrates how revealed- and stated-preference analyses can be used for modeling network effects in the field of mobile telecommunications. The aim of this study was to verify if network effects may still play a role in the Polish mobile telecommunications market, measure their strength, identify their sources and variability across consumers by accounting for consumers' observable and unobservable preference heterogeneity, evaluate their monetary value to consumers, and finally, to verify if the marginal utility associated with network effects is constant. The analysis of consumers' revealed choices (currently used mobile telephone operator) allowed the identification of major differences between customer bases of incumbent and new entrant operators, and insight into the business strategies adopted in the presence of asymmetric regulation of mobile termination rates. The second part of the study—the analysis of the consumers' stated choices (made in carefully prepared and designed hypothetical choice situations, known as the choice experiments) made it possible to directly model consumers' utility functions and, in this way, investigate the nature of network effects in mobile telecommunications markets. From the results, the presence of strong network effects, which are related to the ratio of consumers' social network group using the same operator, and to the magnitude of on-net price discounts, is confirmed. These network effects can be disaggregated to pecuniary and non-pecuniary effects. Through the utilization of the random parameters multinomial logit model, consumers' observable and unobservable preference heterogeneity can be accounted for, which proved a scientifically revealing and potentially policy-relevant approach. The results might be of a particular interest to other researchers aiming at modeling consumers' preferences as well as to mobile telephone operators and regulatory authorities—it is shown that capacity for vigorous price competition between mobile operators is limited by non-price factors, which affect subscriber's choices, especially in the presence of asymmetric mobile termination rates.     

Beyond the flat rate bias: The flexibility effect in tariff choice

Flat rates are a prominent pricing scheme for telecommunications services and are often preferred by consumers although average costs would be lower in an alternative usage-based tariff. Reasons are that flat rates protect against unexpectedly high costs (insurance effect), are more likely to be chosen if actual usage is overestimated (overestimation effect), and prevent any disutility that is associated with the immediate perception of marginal costs (taximeter effect). This study complements the literature on tariff biases by highlighting that a lack of tariff flexibility is a major impediment to choosing a flat rate: empirical support for this flexibility effect is found, while, at the same time, the insurance and overestimation effect that run in favor of flat rates are confirmed. Finally, the managerial implications of the findings for the introduction of the new cost cap tariff are discussed. The hybrid cost cap tariff can combine the flexibility and the insurance property, and may, therefore, exert a cost cap bias on consumers.     

Facilitating computer-supported meetings: A cumulative analysis in a multiple-criteria task environment

There have been many instances of the ineffective applications of new information technology. This article describes a program of enhancing the effectiveness of a new technology, Group Decision Support Systems (GDSS), through a series of studies which resulted in improvements in the technology itself as well as in how the technology is supported. Our approach emphasizes human facilitation and facilitative features embedded in the GDSS software.