Evaluation of energy efficiency of fifth generation mobile systems

There has been active research worldwide to develop the next generation, i.e., fifth generation, wireless network. Next generation mobile communication networks are broadening their spectrum to higher frequency bands (above 6 GHz) to support a high data rate up to multigigabits per second. This work examines how to substantially improve energy efficiency for next fifth generation mobile communication systems. It is depicted how by limited exchange of information between neighboring base stations it is possible to maintain quality of service, over a range of traffic loads, while enabling inactive base stations to sleep. Performance of distributed energy efficient topology management schemes are compared against the system without topology management. Performance evaluation is examined using both analytical and simulation based models. Extensive numerical results show that the schemes deliver a significant energy reduction in energy consumption in the mobile network systems.     

Real-time management of telephone operating company networks:issues and approaches

The authors briefly overview the basic characteristics of legacy network management systems used in telephone operating companies (telcos) and highlight their deficiencies for the emerging network. They further propose a network management methodology for supporting both the embedded base and the new generation of network technologies and services. The proposed approach differs from earlier network management methodologies in three major ways: it is driven by managing service performance and network robustness, rather than managing network equipment; it is based on a global network model that makes “end-to-end” management possible, in contrast to today's highly segmented management; and its decision support and automated applications are “network-state” dependent as opposed to being solely driven by “raw” network measurements     

BPR-UserRec:a personalized user recommendation method in social tagging systems

Social tagging is one of the most important characteristics of Web 2.0 services, and social tagging systems (STS) are becoming more and more popular for users to annotate, organize and share items on the Web. Moreover, online social network has been incorporated into social tagging systems. As more and more users tend to interact with real friends on the Web, personalized user recommendation service provided in social tagging systems is very appealing. In this paper, we propose a personalized user recommendation method, and our method handles not only the users’ interest networks, but also the social network information. We empirically show that our method outperforms a state-of-the-art method on real dataset from Last.fm dataset and Douban.     

Broadband wireless access and future communication networks

This paper presents a vision for wireless communication systems beyond the third generation, which comprises a combination of several optimized access systems on a common IP-based medium-access and core network platform. These different access systems will interwork via horizontal and vertical handover, service negotiation, and global roaming. The different access systems are allocated to different cell layers in the sense of hierarchical cells with respect to cell size, coverage, and mobility to provide globally optimized seamless services to all users. This vision requires extensive international research and standardization activities to solve many technical challenges. Key issues are the global interworking of different access systems on a common platform, the implementation of multimode and multiband terminals and base stations by software-defined radio concepts as well as advanced antenna concepts     

OPNET网络仿真中的校核验证过程研究

网络仿真是一种通过建立网络模型来模拟实际网络行为,从而获取网络特定性能参数的一种仿真技术。论文总结了基于OPNET的网络建模仿真过程,提出了一个针对OPNET网络建模仿真的校核验证过程模型,重点探讨了校核验证过程中各阶段的主要活动、所要达到的校验指标要求以及适用的校验方法。     

The next generation of systems to support corporate grade ICT products and solutions

The delivery of next generation IT and communications services to corporate customers is a principal part of BT’s growth strategy. These services range from IP virtual private networks, to hosted applications, through to fully managed solutions spanning complex IT and network infrastructures. The cost and flexibility of such services is increasingly dependent on the operational support systems (OSS), which automate activities such as provisioning, change, billing, and incident management. However, the OSS challenges for the service provider have never been so great — not only to support a wide-ranging portfolio of legacy products, but also a new generation of convergent products, while at the same time trying to deliver both improved service and cost savings. Moreover, in the corporate sector, large contracts are typically won in partnerships, and through outsourcing. The OSS must therefore interwork seamlessly with the counterpart OSS in each of the partner’s operations, pulling together to deliver a single managed service to the customer. This paper outlines BT’s solution to these complex OSS challenges, the application of its systems capability matrix to corporate customers, the relationship to its alliance with HP, the importance of standards such as ITIL, and how BT is levering its research and venturing capabilities to deliver a competitive edge through OSS.     

A service‐agnostic method for predicting service metrics in real time

We predict performance metrics of cloud services using statistical learning, whereby the behaviour of a system is learned from observations. Specifically, we collect device and network statistics from a cloud testbed and apply regression methods to predict, in real‐time, client‐side service metrics for video streaming and key‐value store services. Results from intensive evaluation on our testbed indicate that our method accurately predicts service metrics in real time (mean absolute error below 16% for video frame rate and read latency, for instance). Further, our method is service agnostic in the sense that it takes as input operating systems and network statistics instead of service‐specific metrics. We show that feature set reduction significantly improves the prediction accuracy in our case, while simultaneously reducing model computation time. We find that the prediction accuracy decreases when, instead of a single service, both services run on the same testbed simultaneously or when the network quality on the path between the server cluster and the client deteriorates. Finally, we discuss the design and implementation of a real‐time analytics engine, which processes streams of device statistics and service metrics from testbed sensors and produces model predictions through online learning.     

Power control and channel allocation for real‐time applications in cellular networks

The next‐generation packet‐based wireless cellular network will provide real‐time services for delay‐sensitive applications. To make the next‐generation cellular network successful, it is critical that the network utilizes the resource efficiently while satisfying quality of service (QoS) requirements of real‐time users. In this paper, we consider the problem of power control and dynamic channel allocation for the downlink of a multi‐channel, multi‐user wireless cellular network. We assume that the transmitter (the base‐station) has the perfect knowledge of the channel gain. At each transmission slot, a scheduler allots the transmission power and channel access for all the users based on the instantaneous channel gains and QoS requirements of users. We propose three schemes for power control and dynamic channel allocation, which utilize multi‐user diversity and frequency diversity. Our results show that compared to the benchmark scheme, which does not utilize multi‐user diversity and power control, our proposed schemes substantially reduce the resource usage while explicitly guaranteeing the users' QoS requirements. Copyright © 2007 John Wiley & Sons, Ltd.     

NGBOSS互联技术研究

根据NGBOSS业务的规划,未来的业务支撑系统分为客户业务运营支撑系统（CBOSS）和产品业务运营支撑系统（PBOSS）,现有BOSS系统星型互联的网络架构不具备对产品全网运营模式的支撑。未来新一代的NGBOSS将采用网状网互联技术,实现各省业务支撑平台间以及与基地业务平台间的互联互通。本文介绍了NGBOSS互联的网络结构、技术框架以及系统实现的关键技术。     

World Wide Web enabled operational support systems — a testing perspective

BT uses many operational support systems (OSS) in the course of its business. The major customer service system (MCSS) is one such OSS used for electronic dialogue with major customers. The client/server approach currently used is being superseded with a call for a World Wide Web (WWW) interface and adoption of a mid-tier server/thin-client approach. This paper examines how practical verification, validation and test (VV&T) techniques can be applied to such systems. Three WWW technologies are examined here as researched and implemented within the MCSS Bali project. The three technologies are Common Gateway Interface (CGI), Java and Citrix WinFrame.     

Service based CAC with QoS guarantee in mobile wireless cellular networks

The increasing variety and complexity of traffic in today's mobile wireless networks means that there are more restrictions placed on a network in order to guarantee the individual requirements of the different traffic types and users. Call admission control (CAC) plays a vital role in achieving this. In this paper, we propose a CAC scheme for multiple service systems where the predicted call usage of each service is used to make the admission decision. Our scheme enables real‐time traffic to be transmitted using shared bandwidth without quality of service (QoS) requirements being exceeded. This ensures that the utilization of the available wireless bandwidth is maximized. Information about the channel usage of each service is used to estimate the capacity of the cell in terms of the number of users that can achieve a certain bit error rate (BER). Priorities assigned to each service are used to allocate the network capacity. An expression for the handoff dropping probability is derived, and the maximum acceptance rate for each service that results in the estimated dropping probability not exceeding its QoS requirements is calculated. Each call is then accepted with equal probability throughout the duration of a control period. Achieved QoS during the previous control period is used to update the new call acceptance rates thus ensuring the dropping probability remains below the specified threshold. Simulations conducted in a wideband CDMA environment with conversational, streaming, interactive and background sources show that the proposed CAC can successfully meet the hard restraint on the dropping probability and guarantee the required BER for multiple services. Copyright © 2005 John Wiley & Sons, Ltd.     

Simulation analyses of weighted fair bandwidth‐on‐demand (WFBoD) process for broadband multimedia geostationary satellite systems

Advanced resource management schemes are required for broadband multimedia satellite networks to provide efficient and fair resource allocation while delivering guaranteed quality of service (QoS) to a potentially very large number of users. Such resource management schemes must provide well‐defined service segregation to the different traffic flows of the satellite network, and they must be integrated with some connection admission control (CAC) process at least for the flows requiring QoS guarantees. Weighted fair bandwidth‐on‐demand (WFBoD) is a resource management process for broadband multimedia geostationary (GEO) satellite systems that provides fair and efficient resource allocation coupled with a well‐defined MAC‐level QoS framework (compatible with ATM and IP QoS frameworks) and a multi‐level service segregation to a large number of users with diverse characteristics. WFBoD is also integrated with the CAC process. In this paper, we analyse via extensive simulations the WFBoD process in a bent‐pipe satellite network. Our results show that WFBoD can be used to provide guaranteed QoS for both non‐real‐time and real‐time variable bit rate (VBR) flows. Our results also show how to choose the main parameters of the WFBoD process depending on the system parameters and on the traffic characteristics of the flows. Copyright © 2005 John Wiley & Sons, Ltd.     

UMTS — the mobile part of broadband communications for the next century

This paper outlines the path from developing broadband ISDN/ATM systems towards the European vision of the next generation mobile system — Universal Mobile Telecommunications System (UMTS).The capabilities of UMTS in terms of services and features compared to the second generation mobile system GSM, and the network technologies behind N-ISDN and B-ISDN, are discussed with proposals for technical developments to satisfy the UMTS requirements. The UMTS radio interface aspects are described and considerations on the network requirements to support these radio aspects are discussed.The requirements within the network for control, switching and transport to support the mobility, service and interconnecting network aspects of UMTS are outlined in conjunction with the technical solutions currently under discussion and some latest thoughts on a potential high-level architecture     

A historical perspective of CSTA

Computer-supported telecommunications applications (CSTA) is one of the more important standards for computer-telecommunications interfaces, addressing service and protocol definitions used to provide a link between computers and telecommunications systems. The services provided on a CSTA link between a telecommunications and computer network work much like the services that telecommunication network provides to a user at an access point. At the point of attachment to a telecommunications network, the “phone numbers” are sufficient to describe the desired object for involvement with a service. If a new object were created for the purposes of CSTA (e.g., a monitoring group), an identifier which would work like a phone number in that network would be assigned to that object. Additional handle-identifiers are created and provided after a service is initiated to differentiate between instances of the service being provided. To show this relationship, a functional model was created     

Wi-Fi 6-based home area network for demand response in smart grid

The past decade has brought prolific developments to power systems that range from large-scale renewable integration to digital twins. Modern power systems consist of highly variable generation clusters. Hence, monitoring and prediction of power generation has become a vital part of today's power systems. On the other hand, detailed real-time information of power usage is also a key parameter for the control algorithms used for the demand side management. With this information flow, power systems become smart grids which offer improved service and enable many advanced operations. In this regard, the home area network (HAN), which collects the power consumption/generation of household devices, plays a key role. So far, a number of technologies such as ZigBee, Z-Wave, and Power Line Communication (PLC) have been considered for the HAN. Yet, widely used wireless local area network (WLAN) technology, Wi-Fi, was not identified as a prominent candidate due to the limitations in its latency and reliability. However, with the introduction of the IEEE 802.11ax standard, Wi-Fi 6 was developed, and it demonstrates guaranteed latency and reliability for its users. Thus, with its widespread deployment in households, Wi-Fi is becoming a natural candidate for HAN. In this article, we present a comprehensive HAN protocol based on Wi-Fi 6 which can achieve guaranteed latency and reliability for HAN users. The results show that when an efficient resource allocation mechanism is in place, using Wi-Fi for HAN does not adversely affect the other Wi-Fi users in the normal WLAN.     

Une plate-forme de validation multi-protocoles et multi-services Résultats d’expérimentation

This article presents the implementation of a validation platform based on formal methods and the experimental results obtained. This platform allows performing conformance and interoperability tests, analysing the specification and constructing a performance model for the services. It covers all stages of the validation which are: formal specification, test architecture definition, test generation and execution for the defined architecture, and performance evaluation. The test methods and architectures used here make it easier to detect and localise errors. The platform has been constructed within the framework of theRnrt (National Telecommunications Research Network) platform project, platonis. This platform is composed of a network integrating the different sites of the project partners. The principal application domains for the platform are telecommunication systems and mobile telephony. In particular, two different cases study are presented that illustrate the platform’s applicability to the test of mobile 3rd generation protocols and services usingWap, gprs andUmts. Nevertheless, the platform is generic and can be used for other types of communication protocols and services.     

Efficient test case generation for validation of UML activity diagrams

Unified Modeling Language (UML) is widely used as a system level specification language in embedded system design. Due to the increasing complexity of embedded systems, the analysis and validation of UML specifications is becoming a challenge. UML activity diagram is promising to modeling the overall system behavior. However, lack of techniques for automated test case generation is one major bottleneck in the UML activity diagram validation. This article presents a methodology for automatically generating test cases based on various model checking techniques. It makes three primary contributions: First, we propose coverage-driven mapping rules that can automatically translate activity diagram to formal models. Next, we present a procedure for automatic property generation according to error models. Finally, we apply various model checking based test case generation techniques to enable efficient test case generation. Our experimental results demonstrate that our approach can reduce the validation effort drastically by reducing both test case generation time and required number of test cases to achieve a functional coverage goal.     

An access cell selection algorithm for next generation mobile environments

Next generation of mobile communications will be based on a heterogeneous infrastructure comprising different wireless access systems in a complementary manner. This paper proposes a network selection algorithm based on user activity, user preferences, service requirements, and networks conditions which provides users a prospect of being always best connected within an environment of heterogeneous mobile networks. This is achieved by a learning process which allows user to select an access network based in previous connections and a cost function that helps the user to select the best network that adapts to the needs.     

智能区域用电安全公共综合服务系统

随着电能的广泛应用,用电负荷越来越大。为保证用户安全用电,文中设计了一种基于分布式网络的综合服务系统。通过实时监测、分析和预测配电系统的运行状况,及时调度维护服务从而实现预知维护,进而缩短故障停电时间,提高用电安全性,同时也降低了配电系统的维护成本。