Real‐time bandwidth renegotiation through learnt behaviour

In many cases traffic is aggregated from several sources, or simply has no well‐understood characteristics, and so it is difficult for the user to decide the basis on which bandwidth should be demanded. A strategy is described to determine the optimum way to decide when to renegotiate the traffic capacity provided in ATM and similar systems. The performance of the strategy is evaluated using simulations on traffic with theoretical distributions and also on recorded real traffic. The strategy appears to work and the results give insights into the very limited benefits obtained by increasing the granularity of the rates provided. Copyright © 2001 John Wiley & Sons, Ltd.     

话务量若干问题的探讨

话务量是话务理论中的一个重要基本概念。经典话务理论已对电路群的流入话务量和完成话务量给出明确的定义。但是由它衍生的一些相关的话务量，如损失话务量，重复话务量等，现有的话务理论没有给出明确的定义。因此，在电信网管理、规划、设计以及话务量统计分析过程中，有关人员常对这些话务量的概念及其计算方法感到不易理解，并在实际应用过程造成了许多困难。本文将试图对这些概念作出科学的定义，并给出其相应的计算方法。     

CDMA网络掉话原因分析

分析了接入与切换碰撞、前向长期干扰、前向短期干扰、前反向链路不平衡、长期覆盖不好、短期覆盖不好、业务信道功率受限等7种类型掉话事件的掉话原因，并总结形成了掉话原因分析模板，将实际测试中遇到的掉话事件和此模板进行比对以帮助分析掉话事件发生的原因。     

具有记忆功能的病房呼叫系统

介绍一种利用８０３１单片机实现的病房呼叫装置。该机除具备普遍呼叫仪的主要功能外，还能记忆１０天内各次呼叫的病号、呼叫时间、护士响应时间等多项数据，并可随时进行打印、集服务，管理和记录等多种功能于一身。     

Network dimensioning at the call level for the always‐on network

It is becoming common for the network to provide always‐on access services, where subscribers are guaranteed that their call requests will never be blocked. This paper studies the call‐level link dimensioning for the always‐on network with single‐class traffic. The call‐level QoS requirement is expressed in terms of the probability of a poor‐quality call, which is the probability that a call experiences packet‐level QoS violation at any time during its duration, as opposed to the probability of blocking in the network with call admission control (CAC). The system is modelled as the M/M/infinite system with finite population and an analytic expression for the probability of a poor‐quality call is derived based on performability analysis. The effects of the call‐level traffic characteristics on the required link resources are studied. It is also shown that the call‐level link dimensioning for the always‐on network needs more link resources than the network with CAC, and the call‐level link dimensioning based on the analytic expression can be used to conservatively dimension the always‐on network with arbitrarily distributed call holding time and inter‐call time. The paper also studies the problem of estimating the call‐level traffic characteristics when the knowledge of call boundaries is not available. Copyright © 2004 John Wiley & Sons, Ltd.     

200号业务在北京的应用与发展

２００号业务近一两年在我国许多大城市迅速发展。北京电信在发展２００号业务时，注重市场调研和培育，积极开拓新业务领域。本文首先介绍了北京２００号业务的开放情况，然后叙述了业务的编号规则、组网方案、平台技术以及２００号业务今后的发展趋势。     

运营商智慧客服体系化建设

从运营商重要的语音客服热线、微信客服智能化发展出发,首先分析了传统客服面临的问题与挑战,对人工智能技术在客服领域应用的关键技术进行了客观的评估,提出人工智能与运营商客服结合的方向和体系化思考。结合某运营商现网实际情况,针对人工智能与运营商客服结合的关键技术和应用实践进行了剖析研究,推进智能语音客服、微信机器人的应用实践,提出现网改造、能力开放、智能应用体系部署解决方案。最后对人工智能在智慧客服中的应用进行了展望。     

Performance analysis of the internet‐protocol multimedia‐subsystem's control layer using a detailed queueing Petri‐net model

In the current trend in telecommunications industry towards all‐internet‐protocol (IP) infrastructures, IP multimedia subsystem (IMS) plays a critical role by providing a coherent data and control‐plane solution for large‐scale live multimedia applications in a flexible and cost‐effective manner. On the other hand, such a large‐scale service platform would inevitably fail without effective support for the quality‐of‐service (QoS) requirements perceived by its users. Among the most important factors that influence user QoS are system performance and scalability. In this paper, a performance model for IMS systems is developed using the queueing Petri nets (QPNs) as the modeling formalism. The model's parameters are tuned based on the measurements carried out using a well‐known IMS implementation. The model is validated against the real system. During the model calibration, the Java garbage‐collector process used in the home subscriber‐server (HSS) implementation was found to be a main factor in the discrepancy between the model and the reality. In addition, the effects of other factors such as the network stack in the operating system are investigated. The validated model is employed to give insights into the scalability of every single instance of IMS implementation. The model is extended to study load balancing among multiple instances of HSS to remove the main bottleneck in the system. It provides a valuable platform for resource management of various components of the IMS ecosystem to support the intended level of QoS for the users.     

An Efficient and Adaptive Bandwidth Allocation Scheme for Mobile Wireless Networks Using an On-Line Local Estimation Technique

The next generation of mobile wireless networks has to provide the quality-of-service (QoS) for a variety of applications. One of the key generic QoS parameters is the call dropping probability, which has to be maintained at a predefined level independent of the traffic condition. In the presence of bursty data and the emerging multimedia traffic, an adaptive and dynamic bandwidth allocation is essential in ensuring this QoS. The paradox, however, is that all existing dynamic bandwidth allocation schemes require the prior knowledge of all traffic parameters or/and user mobility parameters. In addition, most proposals require extensive status information exchange among cells in order to dynamically readjust the control parameters, thus making them difficult to be used in actual deployment.In this paper, we introduce a novel adaptive bandwidth allocation scheme which estimates dynamically the changing traffic parameters through local on-line estimation. Such estimations are restricted to each individual cell, thus completely eliminating the signaling overhead for information exchange among cells. Furthermore, we propose the use of a probabilistic control policy, which achieves a high channel utilization, and leads to an effective and stable control. Through simulations, we show that our proposed adaptive bandwidth allocation scheme can guarantee the predetermined call dropping probability under changing traffic conditions while at the same time achieving a high channel utilization.     

基于CT技术搭建教务成绩查询热线

以“湖北工业大学教务成绩查询热线”服务系统的设计为实例，讨论了呼叫应答中心服务系统，并与单纯基于互联网的客户服务进行了比较。着重从系统的设计思路、系统软硬件、系统功能模块，及系统运行和管理等方面进行了深入阐述。