Telecommunications Environment Research Articles

An IPv4-IPv6 translation mechanism for SIP overlay network in UMTS all-IP environment

Both IPv6 and session initiation protocol (SIP) are default protocols for Universal Mobile Telecommunications System (UMTS) all-Internet protocol (IP) network. In the existing mobile telecommunications environments, an IPv6-based UMTS all-IP network needs to interwork with other Internet protocol version 4 (IPv4)-based SIP networks. Therefore, mobile SIP applications are typically offered through an overlay structure over the IPv4-Internet protocol version 6 (IPv6) interworking environments. Based on 3GPP 23.228, we propose an IPv4-IPv6 translation mechanism (i.e., SIPv6 translator) that integrates different IP infrastructures (i.e., IPv4 and IPv6) to provide an overlay network for transparent SIP application deployment. In this paper, we present the architecture and the call flows of the SIPv6 translator. An analytic model is proposed to investigate the fault tolerance issue of our approach. Our study provides guidelines to select appropriate number of processors for fault tolerance.

The concurrent validity of the technical test battery as an indicator of work performance in a telecommunications company

The purpose of this study was to assess the concurrent validity of the Technical Test Battery (TTB) in a South African telecommunications institution. The Technical Test Battery (TTB) was administered to a sample of 107 technical officers. Their test scores were compared to the scores obtained from a job performance rating scale specifically designed for this position on the basis of a thorough job analysis. The TTB demonstrated high concurrent validity as an indicator of work performance for technical posts in the telecommunications environment. These results suggest that the TTB may have a high predictive validity for performance in technical positions. The findings and implications of the study are discussed. Opsomming Die doel van hierdie studie was om die samevallende geldigheid van die “Technical Test Battery (TTB)�? in ’n Suid-Afrikaanse telekommunikasie instansie te bepaal. Die TTB is op ’n steekproef van 107 tegniese personeel toegepas. Die toetstellings is in verband gebring met die tellings van ’n werksprestasiemaatstaf wat spesifiek vir die pos ontwikkel is op grond van ’n deeglike posanalise. Daar is bevind dat die TTB ’n hoë samevallende geldigheid as aanduider van werksprestasie vir tegniese poste in the telekommunikasiebedryf toon. Dié resultate dui op ’n sterk moontlikheid dat die TTB ’n goeie voorspeller van werksprestasie vir tegniese beroepe kan wees. Die bevindinge en implikasies van die studie word bespreek.

The diffusion of a new technology into the marketplace implementing UMTS

One of the biggest challenges for the telecommunications environment has always been the introduction of a new technology into the market. Introducing a new technology in the market differs greatly from introducing a product as it is not tangible, which necessitates a different approach to the enabling of customers on a new technology. New technologies are generally expensive and therefore there is always a certain resistance in accepting these new technologies. In structuring the diffusion process to the customer at an early stage makes the acceptance of the new technology much easier and less painful.

Providing Throughput Guarantees in 802.11e WLAN Through a Dynamic Priority Assignment Mechanism

Supporting real-time and interactive traffic in addition to traditional data traffic with a best-effort nature represents a constantly rising need in any kind of telecommunications environment. The IEEE 802.11 based WLAN (Wireless Local Area Network) environment does not represent an exception. This is why at different protocol layers, and primarily at the MAC layer, many efforts are being put by both the research community and the standardization bodies to design effective mechanisms for user QoS (Quality of Service) differentiation. Although early results are coming into sight, such as, for example, the IEEE 802.11e standard release, still a thorough research activity is required. Aim of the present paper is to contribute to the cited research issue by proposing an improvement to the "static" traffic prioritisation mechanism foreseen by the IEEE 802.11e MAC (Medium Access Control) protocol. This latter shows a twofold drawback. First, there is no certainty that QoS requirements relevant to a given application are always fulfilled by the "statically" associated priority. Second, resource requests of the applications are not adapted to the (usually highly) variable traffic conditions of a distributed WLAN environment. The algorithm we propose is specifically tailored to "dynamically" assign 802.11e MAC priorities, depending on both application QoS requirements and observed network congestion conditions. It is carefully designed, implemented into a system simulation tool, and its highly effective behaviour assessed under variable traffic and system conditions.

Concepts for the Temporal Characterization of Short Optical Pulses

Methods for the characterization of the time-dependent electric field of short optical pulses are reviewed. The representation of these pulses in terms of correlation functions and time-frequency distributions is discussed, and the strategies for their characterization are explained using these representations. Examples of the experimental implementations of the concepts of spectrography, interferometry, and tomography for the characterization of pulses in the optical telecommunications environment are presented.

QoS requirements for a voice-over-IP PSTN

Voice over IP is already widespread in enterprise private networks and is growing in public switched voice networks as manufacturers withdraw support for earlier technologies. Packet transmission of voice can introduce new impairments, including packet loss, extra sources of delay, and the use of compressed speech coding, all of which may affect voice quality delivered to the user. Factors affecting the quality of a voice telephony connection are described, concentrating on those which are changed by the move to packet transmission, including the complex area of delay. We outline subjective testing based on users’ opinions of fragments of recorded audio material or of connections realised in a laboratory, and describe the abstraction of these results into transmission planning models to assist with design of networks and their QoS mechanisms. QoS requirements are stated for a packet technology to support a PSTN and ISDN service in the UK telecommunications environment.

Telecommunications infrastructure facilitating sustainable development of rural and remote communities in Northern Australia

Telecommunications access in the rural and remote areas of Australia has come under considerable scrutiny in recent years. In the past decade, various Federal Government reports and inquiries have citied inadequate infrastructure, lack of service provision, the high cost of access and “thin” markets as key impediments. Whilst these difficulties are not restricted to rural and remote Australia, they tend to impact disproportionately on regional communities, notably in education and health service provision. Particularly at risk are the indigenous communities in rural and remote regions of Australia. In this paper telecommunications infrastructure is perceived as the lynch-pin for achieving sustainable economic and social development. It is suggested that without appropriate development of information infrastructure, the disparities already experienced by rural and remote communities will be further exacerbated as the reliance of goods and services over computer-mediated networks increases. The paper offers a new paradigm that will assist in maintaining a competitive telecommunications environment and facilitate the sustainable social and economic development of rural and remote communities.

A Dynamic Macroeconomic Based Model for the US Telecommunications Industry

Dynamic models have been used in most businesses serving different purposes. The increased changes of the Telecommunications environment have created a dynamic industry emerging new dynamic economic models. We investigate the Telecom industry by conducting macroeconomic infrastructural analysis for the period 1984-2003. The analysis is focused on several factors for example the infrastructure described by the Teledensity and the Telecom revenues in comparison with the US Gross Domestic Product (GDP). The purpose of this analysis is to understand the industries behavior and design appropriate economic dynamic model, detecting several trends and impact of certain events for example of the Telecom Act.

Extending the stochastic programming framework for the modeling of several decision makers: pricing and competition in the telecommunication sector

We consider the case when part of the uncertainty faced by a decision maker is derived from actions of another independent actor who pursues her own aims. Each party sets its decisions in the next time period in response to the other party's policy. We model this situation by introducing some ideas from game theory, but unlike this theory we do not focus on equilibrium and related optimality notions. Instead, we follow the framework of stochastic programming and take the view of one of the decision makers. Our model is placed in a telecommunication environment with a network owner and operators without their own network facilities. We give an extension to a multiperiod model.

Privacy in (mobile) Telecommunications Services

Telecommunications services are for long subject to privacy regulations. At stake are traditionally: privacy of the communication and the protection of traffic data. Privacy of the communication is legally founded. Traffic data subsume under the notion of data protection and are central in the discussion. The telecommunications environment is profoundly changing. The traditionally closed markets with closed networks change into an open market with open networks. Within these open networks more privacy sensitive data are generated and have to be exchanged between growing numbers of parties. Also telecommunications and computer networks are rapidly being integrated and thus the distinction between telephony and computing disappears. Traditional telecommunications privacy regulations are revised to cover internet applications. In this paper telecommunications issues are recalled to aid the on-going debate. Cellular mobile phones have recently be introduced. Cellular networks process a particular category of traffic data namely location data, thereby introducing the issue of territorial privacy into the telecommunications domain. Location data are bound to be used for pervasive future services. Designs for future services are discussed and evaluated for their impact on privacy protection.

Fixed and mobile service convergence and reconfiguration of telecommunications value chains

The value chain model serves as a proper analytical tool of industry processes, particularly under rapidly changing telecommunications environments. This article attempts to provide a better understanding of the convergence between the fixed and mobile telecommunication industries by investigating changes in the value chains. Specifically, this article develops a new type of fixed-mobile convergence value chain, and highlights the importance of content and application providers in the new value chain. Some examples of fixed and mobile service convergence in Korea are discussed, and these confirm progress in fixed and mobile convergence, and reconfiguration of value chains.

Automatic 3D building reconstruction by integration of digital map and stereo imagery for urban area

Three dimensional model of urban areas is useful in several applications. In urban administration, perspective views derived from three dimensional model are used by city planners for landscape analysis. Three dimensional models are also used in modeling telecommunication environment. Building heights are important in searching for the optimal locations of transmission antennas especially in mobile telecommunication for cell planning. Furthermore, reconstructed 3D buildings are also essential in generating ‘true’ digital orthophotos where occlusion areas caused by tall buildings are eliminated. This paper introduces an automated method of building height and eventually 3D building reconstruction which involves the integration of existing 2D vector geodata (i.e., digital maps) and stereo aerial imagery. Accurate 2D vector geodata of major cities in Korea are available at the scale of 1/1,000. The vertical line locus method has been deployed to recover building heights. Building footprint in the 2D vector geodata is used in locating the vertical guideline along the building edges formed by building sides. Digital elevation model (DEM) was also generated from the contour layer which is included in the vector geodata. DEM values at the foot of the buildings were used as initial searching locations. At a preset incremental value of height along the vertical guideline, evaluation based on the cross correlation image matching technique was carried out to test if the top of the building has been reached. Buildings are reconstructed with flat roof surfaces that are typical shape of the buildings in the study site.

Universal service: beyond established practice to possibility space

A number of proposals have been put forward to reform universal service and make it compatible with the new competitive telecommunications environment in the United States. The diversity and apparent contradictions between these proposals makes the public policy dialog scattered and confused. This paper introduces the idea of a ‘possibility space’ delineated by two dimensions—‘intervention’ and ‘locus’—that lays out the contours of the emerging intellectual landscape by placing past practices as well as present proposals on the same conceptual plane. It suggests that the current approach to universal service reforms continues to be bound by the self-imposed limitations of a past regulatory era, and that a heterogeneous universal service policy is likely to be more suited to the new telecommunications environment.

The Role of Haptics in Immersive Telecommunication Environments

This paper explores the role of haptics in immersive telecommunication applications and analyzes the contribution of haptics to the sense of presence in a variety of applications. Based on the concept of embodied presence, a new construct, resonance between the human cognitive-body system and the streaming sensory information from the environment, is suggested to be a principal factor in "presence." Resonance is defined as the level of mutual synergy between sensory information and action, relative to the physical environment. It occurs when the sensory flow supports action. Since the human haptic system is unique in that it both perceives sensations from the environment and acts on the environment, it has a central role in resonance and in presence. Haptics in the natural world supports efficient bodily action and, in a tacit way, supports development of higher reasoning skills. This requires resonance and embodied presence. The current visual-haptic gap between levels of technological development creates a bottleneck in developing fully tele-immersive applications.

Learner Autonomy and Tandem Learning: Putting Principles Into Practice in Synchronous and Asynchronous Telecommunications Environments

The main title of the recent UNTELE conference refers to the question whether CALL development is technology- or pedagogy-based. In this paper, I will argue, not surprisingly, that it is both. Our own research at the Centre for Language and Communication Studies at Trinity College Dublin over the past 4 years has provided us with valuable insights on the relationship between pedagogy and technology. On the one hand, our centre has for years been actively involved in shaping the concept of learner autonomy, not least through the writings of the centre’s founder, David Little. On the other hand, our involvement in the tandem network and tandem learning as an implementation of learner autonomy principles has given us first-hand experience in various computer-mediated forms of language learning, especially e-mail and object-oriented multi-user domains (MOOs). This paper will first look at three different approaches to learner autonomy: an individual-cognitive, a social-interactive, and an experimental-participatory perspective. I will then explore how these ideas translate into tandem learning, one implementation of learner autonomy in CALL. The third section will deal with asynchronous and synchronous communication tools and language learning frameworks, and I will describe how various combinations of technology and pedagogy can lead to more and also sometimes less successful implementations of learner autonomy principles. I finally look at the relationship of technology and pedagogy and present a three-part model that I consider useful for a discussion of learner autonomy in computer-mediated environments.

Liquid crystal-based optical space switches fordwdm networks

This paper addresses the issue of using conventional liquid crystal materials as reconfigurable holographic or diffractive phase elements within optical space switches and the resulting constraints in their choice and use in a telecommunication environment. We discuss the advantage of this technology for implementing holographic-based approaches with respect to other techniques. As an illustration we give two examples which illustrate two generic architectures and complementary use of liquid crystal to implement them. Finally, we give some trends on implementations of high channel capacity space switches based on this technology.

IMT-2000 기반 컨텐츠 서비스를 위한 보안 프로토콜

IMT-2000은 인터넷 서비스와 멀티미디어 고속 데이터 정보 등 유선예서 제공하고 있는 서비스 대부분을 무선으로 공급하고자하는 사용자의 요구 충족을 위해 등장하였다. 그러나 글로벌 로밍시 신호 데이터 및 사용자 데이터가 타 사업자의 망을 거쳐 전송된다. 또한 고속의 데이터 통신이 제공됨에 따라 기밀성 보호에 필요한 데이터 통신량이 증대될 것으로 판단된다. 최근 IMT-2000사업은 2002년을 기점으로 상용 서비스가 진행될 예정이다. 이러한 시점에서 무선 컨덴츠는 그 특성상 데이터에 대한 제 3자로부터의 불법적인 행위에 대해 많이 노출되어져 있다. 따라서 이동 통신 환경에서의 보안과 인증 문제는 필수적인 사항이라 할 수 있다. 이를 위해 본 논문에서는 기존의 IMT-2000 인증 방식 분석을 통해 더욱 안전하고 효율적인 인증 방식을 제시함과 동시에 무선 컨텐츠 제공에 있어 필요한 보안 프로토콜을 설계하고자 한다. IMT-2000 appeared in order to satisfy the desires of the uses who wish to supply through wireless most of the services being provided through wire, such as Internet services and multimedia high-speed data information. However, during global roaming, the signal data and the user data get transmitted through the networks of other users. Also, it is judged that with the provision of high speed data communication the amount of data communication necessary for confidentiality protection will increase. It is planned that the recent IMT-2000 Project will begin its commercial service in 2002. From this viewpoint, wireless contents, due to their special characteristics, are greatly exposed to illegal actions by third persons. As a result, it can be said that security and certification issues in the mobile telecommunication environment are indispensable matters. For this purpose, it is intended that in this thesis through an analysis of the existent IMT-2000 certification method, a more safe and efficient authentication method is presented and, at the same time, a security protocol necessary in the provision of wireless contents is designed.

The South African telecommunications environment: a brief assessment of regulatory change

Communications play a critical role in transforming society. Governments as the custodians of communications therefore have a serious obligation to ensure that all the people of their country have access to basic telecommunications services. Access to basic communication services is a right because communications is an enabler of social interaction across time and geographic space, a creator of economic development and prosperity for even the most dispersed populations. In South Africa, under apartheid, vast populations of people were excluded from this basic right of having access to communications, resulting in a serious backlog of basic communication services. One of the major objectives of the Afican National Congress (ANC) government when it came to power in 1994 was to ensure that communications were made available to all people even those in the most remote areas of South Africa. These objectives were constrained by a number of factors such as: telecommunications policy that favoured a monopolistic telecommunications environment. To re-engineer the South African telecommunications landscape, telecommunications policy has since 1994 evolved in a revolutionary way.

Self-imaging properties of polychromatic Gaussian beams: application to wavelength demultiplexing and space routing.

We propose an analytical model of the self-imaging of Gaussian beams and discuss the impact of the finite aperture and the beam truncation on the quality of the self-image reconstruction. Extension to polychromatic operation is then presented in the context of wavelength division multiplexing systems. From the first point we derive conditions for good self-imaging, compatible with the requirements of the telecommunication environment. A basic optical setup is then proposed to implement both wavelength demultiplexing and routing in a lensless configuration.

Standards initiatives for Emergency Telecommunications Service (ETS)

This article presents the functional requirements, features, and objectives for the Emergency Telecommunications Service (ETS) in newly emerging telecommunication networks. The ETS is an extension of the International Emergency Preference Scheme (IEPS) of ITU-T Recommendation E.106 and includes additional provisions for multimedia services through a packet-based telecommunications environment. Efforts are underway in the national standards bodies and International organizations to identify, establish, and apply a comprehensive family of ETS standards for the next generation of telecommunication services, which are expected to be a blend of new packet technology with traditional circuit-based infrastructure.