英国移动通信市场的竞争和管制

目前英国是移动通信领域竞争比较充分的国家，英国的消费者以欧洲最低的费用享受着高质量的电信服务。英国电信管制局（OFTEL）通过对消费者享受到的竞争成果、消费者行为、市场结构和供应商行为这四组指标的分析来衡量英国的移动通信市场竞争态势，从而调速管制措施。目前OFTEL对移动通信市场的关注点包括SIM卡锁定、国际温游、价格透明、号码携带和短消息业务所带来的潜在性的问题。     

衰落色散无线信道的电波传播预测与模拟

由多径色散及多普勒频移造成的频率－时间选择性衰落是城市移动无线信道的一个重要特性。在研究分析的基础上建立起了城市无线衰落信道的传播预测模型,并对上述无线信道传播模型的时域衰落特性进行了模拟仿真。     

Designing viable business models for context-aware mobile services

Technologies of 3G and beyond open up new opportunities to develop and commercialize context-aware services that utilize information like user location and social context. Although initial expectations were high, the adoption and diffusion of context-aware services have thus far been limited. Existing literature points to failing business models to explain part of the disappointing uptake. However, most authors focus on the factors that explain failing business models rather than providing practical design issues to improve business model viability. This paper fills this gap by specifying generic mobile business model design issues for the domain of context-aware services. As such, we provide a well-grounded, holistic overview of design issues that are the most critical in developing viable business models for context-aware services, based on interviews with eighteen esteemed practitioners and academics in the mobile services domain, at CEO and Professor level. Our findings indicate key challenges in the service domain (i.e. defining value adding elements, specifying target groups and generating trust of consumers in the service), the technology domain (i.e. integrating emerging technology platforms and safeguarding privacy and security), the organizational domain (i.e. division of existing and new roles in complex value networks, openness of the value network towards new service providers and governing the activities in the value network) and the financial domain (i.e. pricing; dividing costs and revenues and combining multiple revenue models). Our research has scientific implications, because it applies generic mobile business model theory to the context-aware services domain. In addition, we provide practical clues to practitioners with regard to the design issues on which they should focus while developing more viable context-aware business models.     

A simple detector for trellis-coded PSK mobile radio systems

A simple detector for a trellis-coded PSK mobile radio system is proposed. A precoder is added to the regular TC-PSK modulator before convolution coding, and a simple one-bit differential detector is used in the receiver. The decision is made symbol by symbol based on the output samples. The bit error rate of this system is evaluated in fast Rayleigh fading characterizing mobile radio channels by numerical integration.     

Security services for protecting radio mobile systems

The development of radio networks has brought the problem of security specifically related to mobility of terminals sharply into focus, and has created the need for radio network operators to implement new security functionalities. The security level of the analog radio mobile systems (the so-called “first generation ” systems was very low, and these systems were often exposed to massive fraud. The development of digital radio mobile systems (the so-called “second generation” systems: GSM, DECT,. allowed the systematic introduction of cryptology based protection mechanisms. Hence, for gsm networks for instance, the main fraud and confidentiality problems were taken into account at the design stage and a security architecture was implemented to provide security services to users and network operators. The third generation mobile telecommunication systems belonging to the imt- 2000 family (which are still under specification within standardisation bodies in particular within the 3gpp worldwide third generation partnership project) will, in the forthcoming years, provide a wide variety of services on a single terminal in a multi-environment (domestic, public, business), multi-operator, and multi-service provider context. Security will be based on second generation systems security functions that have proved to be needed and reliable, and shall be adapted and improved to resolve security threats underlying to new services supplied by third generation radio systems. This document presents examples of security solutions currently implemented for protecting second generation radio mobile systems against frauds and attacks and gives an overview of potential solutions for protecting future third generation radio mobile telecommunication systems.     

全球移动蜂窝通信的革命

近年来，移动蜂窝通信的发展速度可谓骇世惊人。１９９０年，移动用户有１１００万，到１９９８年底达到了３亿多个。据预测，在今后１０年中移动蜂窝用户数将超过固定电话。本文研究了全球移动蜂窝通信的发展状况，就技术革命、服务提供、管制、接入、价格以及发展前途等方面进行了详细的论述。     

Adaptive radio resource assignment for simultaneous services

An adaptive algorithm for selecting rate matching parameters has been developed to satisfy the operating frame error rate requirements for simultaneous services in 3G Universal Mobile Telecommunications System (UMTS) under Rayleigh fading channels. The results show that the adaptive algorithm can achieve the target error rates for multiplexed services of varying data rates and types, and only requires a few adjustments for convergence.     

Mobile services put in context: A Q-sort analysis

Purpose

Objective of this paper to evaluate mobile services on a limited set of characteristics, e.g. usage context, the Innovativeness of the service, efforts required of users for using the service, the usefulness of the service and the likelihood with which it will be used, in order to show that distinction between services is highly relevant for adoption and acceptance research.

Design/method/approach

In this research the mobile services are object of study and therefore an exploratory approach making use of Q-sort methodology is used.

Findings

The characteristics of the 48 services under study play an important role when judged on the five dimensions. Advanced services, explicitly exploiting the mobile nature of the services like navigation and localization, embedded in all kind of task and process related activities, stood out as the most innovative services, however these are the least likely to be used because they are expected to fit day-to-day routines and usage context the least. Easy to use services and services that fit most contexts are most likely to be used.

Practical implications

Designers of mobile services and applications have to be aware of the subtle interplay between usage context, the service or application to be designed, the ease of use. Only when all these factors are taken into account the services may have value to users.

Original value

This is one of the very few studies focused on mobile services, instead of user perception and behavior. In most research on mobile service adoption and acceptance the characteristics of services are threatened as a black box. This paper shows how relevant it is to look into characteristics of mobile services themselves.     

Mobile TV as Part of IMT Advanced: Technology,Market Development,Business Models and Regulatory Challenges

The paper is an exploratory study of the technological and market development potentials of mobile TV as part of IMT Advanced. Different mobile TV platforms and technologies are already available on the market, and huge resources are allocated to push the development forward. The technology solutions, business models and the regulatory framework are in many respects disruptive and present major challenges for the possible success of mobile TV services. In this paper the technology solutions are analyzed for the four major mobile TV platforms/technologies: MPVR (podcast), In-band services, Wireless/Mobile IPTV and the Converged Platforms; the regulatory challenges are identified and the revenue models and interests of the stakeholders are discussed as an indicator of the future changes in market structure and organisation.

Performance of M-QAM modulations for indoor radio communications with combined diversity and equalization techniques

Digital indoor radio communications systems have become an attractive proposal as they could provide the user high quality voice and low rate data services with total mobility. However, indoor communications are affected by multipath propagation that restricts their application imposing an upper limit on the system data rate. To overcome this drawback diversity and channel equalization could be considered. In this paper the performances of 4, 16 and 64-QAM modulations in a radio communications indoor environment are presented. The results show that a system without protection has very limited performance. Diversity techniques are efficient when the radio channel can be assumed to be non-selective. For systems operating in selective fading channels joint equalization and diversity techniques are necessary to fight the degrading effect introduced by the channel. Moreover, if correlation between the two diversity channels is taken into account, the system performances remain almost unchanged, assuming that the correlation coefficient between the two diversity branches is lower than 0.6 to 0.7 approximately.     

Management of networks and services in a composite radio context

This article adopts the assumption that different wireless access technologies (e.g., UMTS, HIPERLAN2, and DVB-T) can be cooperating components of a composite radio infrastructure. The coordinated management of services and network in this heterogeneous context is a complex task. This article presents a service and network resource management platform for wireless systems that operate in a composite radio context. Aspects addressed are the requirements, high-level platform design, functionality of the components that conduct monitoring, resource brokerage, service management, and network resource optimization. Indicative results are presented and concluding remarks provided.     

A compact fractal microstrip antenna for GPS and terrestrial radio services

The multi-band frequency operation is a property that antennas, utilized in several communication systems, have to exhibit. In this paper, a compact printed antenna for Global Positioning System (GPS) and terrestrial radio services is presented. It is composed via the union of four inverse Koch fractal patches. The antenna operates in three frequency ranges (GPS, Digital Cellular System-DCS1800 and 2.7?GHz). It is driven by two feed probes, directly matched to the radiating element without any matching network to be necessary. At GPS, the antenna is capable of generating a circularly polarized field, with maximum strength at the broadside direction. At the other two frequencies, the field is linearly polarized and the maximum of radiation appears apart from the broadside. Two pins, embedded in the structure, are activated at DCS and at 2.7?GHz in order to enhance the performance of the antenna.     

Mobile services with handset bundling and governmental policies for competitive market

Governmental policies can significantly affect the social adoption of services offered by communication technology providers and competition between service providers. Following the implementation of several policies by the Korean government and mobile network operators’ promotion of mobile handset bundling, consumer adoption rates of the latest mobile phone and communications services have been higher in Korea than in other countries. Mobile handset bundling provides consumers the bundled sale of mobile phones and services, but this practice can restrict consumers’ choice of services and limit competition among service providers. This study analyses this ambivalent effect of bundling by mobile network operators (MNOs) and evaluates the outcomes of the Korean government policies (2011–14) using market statistics. Our results highlight that the policies have produced changes in market share but the government needs to promote service differentiation among providers.     

ICTs and radio in Africa: How the uptake of ICT has influenced the newsroom culture among community radio journalists

This article highlights the influence that new ICTs and Computer Mediated Communication is having on the newsroom cultures among community radio journalists in Africa, especially the use of mobile phones and the internet. The discussion is based on findings from a research study that investigated the impact of ICTs on community radio using regional case studies from three African countries – Mozambique, Uganda, and Mali. We argue that the integration of ICTs impacted journalism practice positively as it improved information gathering, processing, distribution, storage, and engagement with the communities, particularly through the use of mobile phones and the internet. However, the synergy with rural community radios that tend to be located in remote areas is yet to be felt in the three countries. While the community radio stations in semi-urban areas or those situated in areas with fairly good infrastructure have better capacity for integration of ICTs and their sustainability, the rural-based community radio stations are greatly inhibited in their integration of new ICT due to lack of the electricity or regular power supply, the high fees charged by the service providers (internet and telephone), as well as the high cost for the ICT equipment, maintenance expenses and operational costs. The article calls for more support for infrastructural development to rural-based community radio stations to close the rural–urban gap and to enable the journalists working there to benefit from ICT integration like their counterparts in the semi-urban and urban community radios.     

瑞典电信市场综述

瑞典于1993年5月颁布电信法，由此建立许可证制度。1996年，修改后的电信法对电信运营商实行不对称管制，只对占有市场主导地位的企业进行严格的监控。1997年7月，瑞典政府再次修改电信法，目的在于使之与欧盟的管制框架保持一致，增加了很多关于许或证持有者的责权规定，在固定业务市场，作为传统运营商的国有Telia公司占有绝对优势，其次是Tele2。Telia Mobile,Tele2 Mobil,Europolitan和Tele8 Kontakt是提供移动通信业务的4家运营商。     

Resource allocation for heterogeneous services in multiuser cognitive radio networks

This paper considers a downlink cognitive radio network consisting of one cognitive base station and multiple secondary users (SUs) that shares spectrum with a primary network. Unlike most of previous studies that focus on the SUs that carry only one type of service, in this paper, the SUs that carry heterogeneous services are considered. Specifically, the SUs are classified by service types, that is, the SUs that carry nonreal‐time services and the SUs that carry real‐time services. The QoS of the nonreal‐time SUs is guaranteed by the minimum mean rate constraint, whereas the QoS of the real‐time SUs is guaranteed by the minimum instantaneous rate constraint. Under this setup, a joint subchannel, rate, and power allocation scheme based on dual optimization method is proposed to minimize the mean transmit power consumption of the cognitive base station. The complexity of the proposed scheme is linear in the number of subchannels and the number of SUs. Extensive simulation results are provided to validate the proposed resource allocation scheme. Copyright © 2012 John Wiley & Sons, Ltd.     

充分发挥业余无线电在应急通信中的作用

在突发自然灾害，电通信网络瘫痪，政府机关之间的沟通阻断，无法与外界保持有效联系的情况下，无线电管理机构应该如何利用无线电管理资源，快速有效地为政府建立应急通信系统呢？我们认为，整合现有管理资源，广泛动员组织各种社会力量，将业余电台纳入应急通信体系，是无线电管理机构应对突发事件的一条有效路径。     

Empirical formula for propagation loss in land mobile radio services

An empirical formula for propagation loss is derived from Okumura's report in order to put his propagation prediction method to computational use. The propagation loss in an urban area is presented in a simple form: A + B log10R, where A and B are frequency and antenna height functions and R is the distance. The introduced formula is applicable to system designs for UHF and VHF land mobile radio services, with a small formulation error, under the following conditions: frequency range 100-1500 MHz, distance 1-20 km, base station antenna height 30-200 m, and vehicular antenna height 1-10 m.     

Resource allocation for non-real-time services in OFDM-based cognitive radio systems

We study the resource allocation (RA) problem in a multiuser OFDM-based cognitive radio (CR) system for non-realtime (NRT) applications in which average user data rates are to be maintained proportionally. In contrast to existing algorithms designed for multiuser OFDM systems, which are unable to guarantee users proportional rates when applied in a CR system, the proposed optimal RA algorithm ensures that CR user rates are maintained in proportion to predefined target rates while at the same time providing an improved system throughput.