On management of CATV full service networks: a European perspective

The CATV network operators hope to offer digital services and evolve their networks to full service networks. There are many hurdles for them at the moment in the transition to a digital network and digital service offering from the current analog-based technology. Key to the success of the transition will be a well-integrated and capable management system to allow CATV operators and service providers to control the network as well as the services they will offer. The CATV operators need to agree on a common data communication infrastructure and plan how their new digital services will be offered to subscribers without disrupting the current customer base of analog service users. The choice of network technology and data communication protocols will have a strong influence on the network management technology chosen. A vital element for the provision of a common open communication architecture as well as for the purposes of network management is that the IP is used. The adoption of existing standards is vital in order to establish a fast route to open network management for CATV networks. It is possible that CATV operators and service providers will have to integrate existing SNMP management systems and TMN/OSI management, with newer integrated service management systems based on TINA and implemented on a CORBA platform. There is a strong need to address security issues before any of these technologies can be deployed for service. There is currently investment (deployed systems and research) which uses each of the technologies mentioned, so these technologies will need to coexist. This article highlights the differences between the North American and European network architectures, and outlines the European network and network management scenario. This is based on the authors involvement in a Pan-European CATV project, Integrated Broadband Communication over Broadcast Networks-IBCoBN     

QoS provision in wireless access networks: a routing perspective considering mobility

Future wireless communications are expected to provide mobile users access to the desired service with the appropriate quality at any place. The essential elements for assembling such a vision are mobility, quality of service (QoS) provision and scalability, which are expected to be merged into the design process of wireless access networks. Internet mobility support is currently entering a mature phase in which scalable solutions provide low loss or even seamless handovers in cellular and heterogeneous mobile environments. Wireless and mobile QoS architectures extend the equivalent Internet approaches in order to accommodate the requirements associated with the presence of wireless links and mobility. Nevertheless, none of the popular mobility proposals combined with wireless and mobile QoS architectures encounter QoS in the routing function, leaving the QoS provision underutilized. QoS routing (QoSR) complements existing QoS architectures, enhancing application performance especially in the case of congestion, while providing efficient resource management. However, QoSR was originally designed for fixed IP networks without taking mobility into account. This paper investigates the interaction of QoSR in wireless access networks, identifying key points for the efficient cooperation with mobility and existing QoS architectures. Copyright © 2009 John Wiley & Sons, Ltd.     

Home networks: a standards perspective

An overview of home networks, as defined by the Home Networking and IT (HNIT) Division of the Consumer Electronics Association (CEA), is presented in this paper. HNIT's membership includes consumer electronics executives, marketing and market research professionals, engineers, and standards developers, which provide a broad perspective on this subject. The article first introduces the rational behind the definition. From that baseline, it moves on to review some of the most critical issues home networks must address so as to meet the expectations of content and service providers-and ultimately those of the consumer. With that foundation, the article provides an overview of each of the major home networking protocols and standards, as well as their respective strengths and weaknesses. Also included is a discussion of the interrelationships between the major standards and industry specifications: in other words, how they will work together to create a seamless home network environment     

Software radio technology: a European perspective

Software radio has emerged as a priority theme of research in Europe. This tutorial review provides a European perspective on technical and commercial issues in the field. Significant differences exist between North American and European views of software radio in personal communications services. This article explains the reasons for these differences. It explains how the European marketplace is influencing short-term directions taken in the commercialization of software radio technology initially at the application layer. Some research is related to handset architectures and to generic RF and digital technologies focused on third-generation systems-Universal Mobile Telecommunications Systems. Software base stations, including their synergies with adaptive (often now termed soft) antennas are also addressed     

Evolving artificial neural networks

Learning and evolution are two fundamental forms of adaptation. There has been a great interest in combining learning and evolution with artificial neural networks (ANNs) in recent years. This paper: 1) reviews different combinations between ANNs and evolutionary algorithms (EAs), including using EAs to evolve ANN connection weights, architectures, learning rules, and input features; 2) discusses different search operators which have been used in various EAs; and 3) points out possible future research directions. It is shown, through a considerably large literature review, that combinations between ANNs and EAs can lead to significantly better intelligent systems than relying on ANNs or EAs alone     

Adaptive digital access protocol: a MAC protocol for multiservicebroadband access networks

The authors describe a protocol that can adapt to the changing demands of a mix of synchronous transfer mode (STM) and asynchronous transfer mode (ATM) applications and efficiently allocate bandwidth to a variety of bursty traffic sources. In the case of a hybrid fiber-coaxial (HFC) network, the protocol resides in customer premises equipment (CPE) and a common head-end/central-office (HE/CO) controller. A medium-access control (MAC) processor provides for dividing the time domain for a given digital bitstream into successive frames, each with multiple STM and ATM time slots. Within the STM region of a frame, variable-length time slots are allocated to calls (e.g., telephony, video telephony) requiring different amounts of bandwidth. In the upstream channels, a contention access signaling time slot is also provided in the STM region for call control and setup requests. Within the ATM region, fixed-length time slots accommodate one individual ATM cell. These ATM time slots may be reserved for a user for either the duration of a call or a burst of successive ATM cells, or shared via a contention process. At least one contention time slot is available for signaling messages related to ATM call control and setup requests. The MAC-layer protocol, its relation to circuit- and ATM-amenable applications, and its performance with respect to throughput, latency, and bandwidth efficiency for several service scenarios are examined     

Pan European R&D: a perspective

New goals for Europe-wide technology policy are emerging, perhaps rather late in the day. In the early 1980s, Europe's leadership was seeking ways to help its large electronics producers hold their own against stiff US and Japanese competition. Now, nearly two decades later, many European companies still lack a competitive edge, and worry about unemployment has deepened. Yet, because of maturing views about the world economy, the focus of the policies of the European Union (EU) has changed. Large companies are seen as fighting for shares of intensely competitive global markets, in which uncertainty and innovation have become a way of life. While retaining a base in their home country, they conduct business around the world. Thus, most multinationals collaborate on the one hand at the regional and local levels, with many firms both large and small, and on the other hand at the global level, with other multinationals. Why, then, adopt technology policies that pay them to collaborate in conducting R&D, which they all do anyway. It would seem far more sensible to encourage the diffusion of new technologies and promote the health of smaller, under-capitalized companies. European technology policies have already influenced tendencies in this direction. They have encouraged collaboration among firms and research institutions across the European Community. Thanks to the Brussels-based R&D programs, companies have learned to work with firms beyond their national borders as a matter of routine, to seek new opportunities beyond their traditional home markets, and generally to think in European terms     

Broadband PLC access systems and field deployment in European power line networks

Data communications over low voltage power distribution networks provide an alternative and cost-effective last mile access technology. It offers data and voice services to users in residential and business areas. Currently, many field trials with different broadband power line communications systems are running worldwide. This article describes one of these systems for the last mile application in European power line networks. It addresses major field deployment aspects, such as range, coverage, coupling, and intercell interference.     

Gigabit local area networks: a systems perspective

A broad overview of gigabit local area networks (LANs) is presented from a systems perspective. Motivations and technical goals of gigabit LANs and challenges of coping with highly bursty traffic and large bandwidth mismatches between network links are described. The focus is on concerns unique to gigabit LANs, especially issues that differentiate them from gigabit wide area networks (WANs), metropolitan area networks (MANs), and lower-speed LANs. Major systems issues are discussed, and possible solutions, such as the virtual-connection architecture, are presented. The hardware technology required by gigabit LANs is illustrated by SONET components     

基于有线网的接入网络

本地电话经营者多年来一直垄断着本地电信市场,目前产值已近1000亿美元。但是,1996年“电信法”的公布打破了这一垄断,电信市场向竞争者开放了。竞争者中包括颇具竞争实力的本地交换通信公司(CLEC)和长途电信公司。能让商业用户全天不间断地与因特网联网的专用数据接入业务是本地电话     

Protecting local access telecommunications networks: Toward a minimum-cost solution

The problem of designing fibre-optic networks for local-access telecommunications generates (at least) three non-trivial subproblems. In the first of these subproblems one must determine how many fibre-optic cables (fibres) are required at either end of a street. In the next subproblem a minimum-cost network must be designed to support the fibres. The network must also provide distinct paths from either end of the street to the central exchange(s). Finally, the fibre-optic cables must be placed in protective covers. These covers are available in a number of different sizes, allowing some flexibility when covering each section of the network. In this paper we describe a dynamic programming (DP) formulation for finding a minimum-cost (protective) covering for the network (the third of the subproblems). This problem is a generalised set covering problem with side constraints and is further complicated by the introduction of fixed and variable welding costs. The DP formulation selects covers along each arc (in the network), but cannot exactly model the fixed costs and so does not guarantee optimality. We also describe an integer programming (IP) formulation for assessing the quality of the DP solutions. The cost of the networks constructed by the IP model is less than those designed using the DP model, but the saving is not significant for the problems examined (less than 0.1%). This indicates that the DP model will generally give very good solutions. Furthermore, as the problem dimensions grow, DP gives significantly better solution times than IP.     

Channel access protocols for Ku-band VSAT networks: a comparativeevaluation

The performance of candidate protocols for first-generation Ku -band very small aperture terminal (VSAT) satellite networks is compared. The goal is to assist the process of selecting a protocol. The performance comparison is carried out over a range of possible traffic, channel and satellite parameters, leading to an understanding of the appropriate regime for each of the protocols under consideration. The protocols considered are unslotted Aloha, slotted Aloha, selective-reject (SRE) Aloha, and demand-assigned time-division multiple-access (TDMA) or DAMA     

Sensor networks with mobile access: optimal random access and coding

We consider random access and coding schemes for sensor networks with mobile access (SENMA). Using an orthogonal code-division multiple access (CDMA) as the physical layer, an opportunistic ALOHA (O-ALOHA) protocol that utilizes channel state information is proposed. Under the packet capture model and using the asymptotic throughput as the performance metric, we show that O-ALOHA approaches the throughput equal to the spreading gain with an arbitrarily small power at each sensor. This result implies that O-ALOHA is close to the optimal centralized scheduling scheme for the orthogonal CDMA networks. When side information such as location is available, the transmission control is modified to incorporate either the distribution or the actual realization of the side information. Convergence of the throughput with respect to the size of the network is analyzed. For networks allowing sensor collaborations, we combine coding with random access by proposing two coded random access schemes: spreading code dependent and independent transmissions. In the low rate regime, the spreading code independent transmission has a larger random coding exponent (therefore, faster decay of error probability) than that of the spreading code dependent transmission. On the other hand, the spreading code dependent transmission gives higher achievable rate.     

Evolving intelligent interexchange network-an SS7 perspective

The role of common channel signaling, referred to as Signaling System No.7 (SS7), in the evolution of services in an interexchange carrier environment is discussed. The importance of SS7 in evolving the intelligent network necessary to support these services is addressed. Interworking with virtual private networks via the out-of-band ISDN messaging channel (D-channel) to extend the capabilities of SS7 network signaling to customer networks is also discussed. For ubiquitous support of ISDN, CLASS, and future services, the interworking of interexchange SS7 with domestic local exchange carriers as well as foreign administrations is critical. This service and intelligent network evolution is described. Emphasis is placed on services and the anticipated migration to those types of services which demand an intelligent interaction and close coupling of both virtual private networks and local public switched networks to the interexchange network     

Neural networks: an engineering perspective

The development and application of neural networks are presented from an engineering perspective. It is stated that neural computing is a collection of mathematical techniques that have been gaining growing acceptance as plug-compatible replacements for statistical and other data-modeling techniques. Two of these techniques, function approximation and clustering, are discussed. The forces shaping the future of neural networking systems, including plug compatibility, hybrid systems-neural computing concepts integrated with expert systems, fuzzy logic, and genetic algorithms-and application specification systems, are reviewed     

Full-duplex medium access control protocols in wireless networks: a survey

Medium Access Control (MAC) protocol plays an important role in full-duplex wireless networks. Theoretically, full-duplex communications have this ability to increase the capacity of traditional half-duplex wireless systems by up to twice. However, designing and implementing an efficient MAC protocol is a central issue in this way. Increasing throughput, collision avoidance, and fairness are common challenges in designing an efficient full-duplex MAC protocol. After giving a short introduction to the general classification of traditional MAC protocols, IEEE 802.11 MAC protocol, and the identified challenges of full-duplex communications in wireless networks, this review paper provides a comprehensive survey of current major MAC protocols for full-duplex wireless communications and classifies them in to three categories i.e. distributed wireless local area networks, centralized wireless local area networks, and other types of networks. This paper also explores and gives a comparative analysis of current full-duplex MAC protocols with stating their advantages and disadvantages as well as comparing them one with another.

     

WRAP: a medium access control protocol for wavelength-routedpassive optical networks

We describe the WDM request/allocation protocol (WRAP), a media-access control protocol for wavelength-routed passive optical networks (WR-PONs) in which each node has a single fixed optical receiver and a single tunable optical transmitter. The protocol does not require a carrier sensing capability, a separate control channel, or any centralized control or scheduling. Access to transmission channels is regulated by allocations made at destination nodes in response to requests made by source nodes. Computer simulation is used to investigate three different allocation algorithms, one of which-the preferential/random algorithm-is shown to provide significantly better performance than the alternatives. Simulations are presented comparing the performance of WRAP to two previously proposed applicable protocols-the interleaved time division multiple access (I-TDMA) protocol, and the FatMAC protocol. WRAP is shown to provide fair and flexible access to the transmission capacity, enabling high network utilization to be achieved under a wide range of traffic conditions, while providing a guaranteed minimum bandwidth between each source-destination pair. We conclude that of the three protocols considered here, WRAP is the best-suited to general-purpose data communications applications such as local, campus, and metropolitan area networks     

Seamless handover in terrestrial radio access networks: a case study

Next-generation networks will overlay heterogeneous networking technologies. In order to enable seamless communications in such an environment, providing support for efficient handover between the various access technologies will play a crucial role. The present article provides a quantitative analysis of it Mobile IPv4-based WLAN-GPRS handover prototype, identifies a number of side effects related to the link layer and routing mechanisms, and presents the impact of handover on UDP and TCP data traffic as well as on Mobile IP signaling itself.