An Efficient Mechanism for Multicast Data Transmission in UMTS

In this paper, we present an efficient scheme for the multicast transmission of the data in the Universal Mobile Telecommunications System (UMTS). We take advantage of the tree topology of the examined network and we introduce the use of Routing Lists (RLs) in the nodes of the UMTS. The adoption of these lists leads to the decrement of the transmitted packets and to the efficient use of network resources in the multicast transmission of the data. We describe in detail the appropriate steps for the successful multicast transfer of data. Furthermore, we analyze the handling of special cases such as user mobility scenarios. Especially, the various handover types are examined along with the Serving Radio Network Subsystem relocation procedure. Finally, we implement our approach in the NS-2 simulator and we present the performance of the multicast mechanism.     

UMTS网络规划仿真介绍

系统仿真是UMTS网络规划和无线资源参数研究的重要手段.本文介绍了UMTS网络规划系统仿真的目的、方法和手段,并探讨了它在网络规划和组网中的意义.     

爱立信GGSN网元安全分析和风险防范

本文对爱立信J20GGSN网元的组网安全进行详细分析,提出了相应风险防范策略措施,为核心网组网安全优化工作提供指导和参照。     

Fast-Unreserved Failure Restoration for Meshed Intelligent Photonic Networks

In this article, an unreserved restoration solution for fast failure restoration in intelligent photonic networks is proposed. The unreserved restoration scheme is a real-time restoration technique that allows for utilizing network capacity dynamically and with full flexibility. However, it has the disadvantage of having a long restoration time as real-time redials are required after a failure is detected. The restoration time is crucial because long restoration times can result in data loss that is not expected, especially in high-speed networks. The proposed method targets reducing the aggregated optical cross-connect switching time to minimize real-time failure restoration time. With the proposed solution, in an event of failure, the restoration time can be reduced to times that are similar to those achieved in the reserved schemes. Common unreserved schemes have an inherent need for retries because the first try after failure detection and notification cannot always be guaranteed due to lack of network resource. In this paper, an enhanced implementation for the proposed solution is designed and described, which allows the features of the proposed solution to be fully realized and overcomes the inherent drawback of redundant OXC switching events for retries in common unreserved schemes. Through simulation experiments, it is shown that under a given network condition, the real-time path setup time for failure restoration required in the proposed solution can be improved by 68% compared with the common unreserved schemes.     

GGSN容量与内容计费规则的关系模型的研究

为探寻GGSN(gateway GSN,网关GSN)设备容量和内容计费规则间的关系,本文建立了GGSN容量与内容计费规则条数和内容计费规则排列顺序间的关系模型。经实测数据验证,所建立的关系模型具有统计学意义上的可靠性。     

User Needs for Services in UMTS

Wireless Personal Communications - The business cases for the emerging Universal Mobile Terrestrial System (UMTS) networks can only be fulfilled if the present voice revenues are expanded by...     

改进的混合MAP-POCS超分辨率图像复原算法研究

超分辨率图像复原技术在不改变硬件的条件下可提高成像系统获取图像的分辨率。研究了图像退化机理,建立了精确的图像退化过程模型,提出一种改进的混合MAP-POCS复原算法,将POCS的凸集约束条件加入到MAP估计过程中。运用峰值信噪比(PSNR)等评价手段对复原图像进行质量评价。仿真结果表明,改进的混合复原算法能够有效地保证复原求解的收敛性并保持复原图像的边缘细节,提升了超分辨率的复原效果。     

Dynamic Power Saving Mechanism for 3G UMTS System

This paper investigates the power saving mechanism of Universal Mobile Telecommunications System (UMTS). UMTS discontinuous reception (DRX) is exercised between the network and a mobile station (MS) to save the power of the MS. The DRX mechanism is controlled by two parameters: the inactivity timer threshold t _I and the DRX cycle t _D . Analytic analysis and simulation model are proposed to study the optimal t _I and t _D selections that maximize the MS power saving under the given mean packet waiting time constraint. We also devise an adaptive algorithm called dynamic DRX (DDRX). This algorithm dynamically adjusts the t _I and t _D values to enhance the performance of UMTS DRX. Our study quantitatively shows how to select the best inactivity timer and DRX cycle values for various traffic patterns. We also show that DDRX nicely captures the user traffic patterns, and always adjusts the t _I and t _D close to the optimal values.

Cost analysis and efficient radio bearer selection for multicasting over UMTS

Along with the widespread deployment of the Third Generation (3G) cellular networks, the fast‐improving capabilities of the mobile devices, content, and service providers are increasingly interested in supporting multicast communications over wireless networks and in particular over Universal Mobile Telecommunications System (UMTS). To this direction, the Third Generation Partnership Project (3GPP) is currently standardizing the Multimedia Broadcast/Multicast Service (MBMS) framework of UMTS. In this paper, we present an overview of the MBMS multicast mode of UMTS. We analytically present the multicast mode of the MBMS and analyze its performance in terms of packet delivery cost under various network topologies, cell types, and multicast users' distributions. Furthermore, for the evaluation of the scheme, we consider different transport channels for the transmission of the multicast data over the UMTS Terrestrial Radio‐Access Network (UTRAN) interfaces. Finally, we propose a scheme for the efficient radio bearer selection that minimizes total packet delivery cost. Copyright © 2008 John Wiley & Sons, Ltd.     

UMTS系统移动定位技术

本系统地介绍了第三代移动通信系统的主要标难之一——UMTS系统的移动定位技术方案，阐述了支持定位功能的网络结构与操作流程，从定位原理、精度、实现方案、对网络和终端设备的影响等方面，对几种主要的标准定位技术进行了综合分析与比较，最后简要概括了最新的发展和应用状况。     

Multicast in UMTS: evaluation and recommendations

It is known that multicasting is an efficient method of supporting group communication as it allows the transmission of packets to multiple destinations using fewer network resources. Along with the widespread deployment of the third generation cellular networks, the fast‐improving capabilities of the mobile devices, content and service providers are increasingly interested in supporting multicast communications over wireless networks and in particular over Universal Mobile Telecommunications System (UMTS). Multicasting is a more efficient method of supporting group communication than unicasting or broadcasting, as it allows transmission and routing of packets to multiple destinations using fewer network resources. In this paper, the three above mentioned methods of supporting group communication are analyzed in terms of their performance. The critical parameters of primary interest for the evaluation of any method are the packet delivery cost and the scalability of the method. Copyright © 2006 John Wiley & Sons, Ltd.     

UMTS系统和LTE系统的业务流程对比浅析

从业务流程的视角对UMTS系统和LTE系统进行了对比分析,直观地说明了LTE系统比UMTS系统在设计上的合理性和先进性。通过一些关键流程,如RRC连接建立、附着过程、会话过程,简明扼要地解释了LTE系统的时效性高于UMTS系统的原因。     

Manual and Automatic Design for UMTS Networks

This paper describes manual and automatic design strategies of UMTS networks. The design aims at adjusting antenna parameters: antenna pattern, tilt and azimuth angles, as well as the common channels' transmitted power to improve the network performance in terms of coverage, capacity, quality of service and service continuity. The manual design strategy is based on an expert system that analyzes different quality criteria of the network and suggests the designer the most effective parameter modifications. The automatic design strategy is based on a Genetic Algorithm that orchestrates the design process. Two optimisation models are considered: the first one uses constant load hypotheses in the network evaluation; the second one takes into account inhomogeneous traffic distribution and utilizes accurate modelling of basic UMTS quantities such as power, load and interference. Detailed examples of network optimization illustrate the effectiveness of the design strategies.     

UMTS网络中的UTRAN关键指标测试

首先介绍了UMTS网络结构与接口协议栈,接着介绍了UMTS关键指标及相关过程,然后说明了UMTS关键指标的定义与实现。     

UMTS及EPC网络QoS机制的研究

随着社会的发展,用户对业务质量的需求也日益提高,为此3GPP组织加强了对QoS的研究,在UMTS阶段引入了端到端QoS机制,并在LTE阶段对QoS机制进行了扩展和增强,目前QoS的研究是3GPP研究的一个热点。本文对3GPP移动通信网QoS演进进行了介绍,分析了UMTS和EPC网络的QoS实现机制,并对两种QoS实现机制进行了分析。     

欧洲UMTS移动通信系统Qos保证体系结构

根据ETSI关于通用移动通信系统（UMTS）服务质量保证方面的一些研究报告^[1]和3GPP的相关协议[2,3]，介绍了UMTS QoS控制机制定义的原则，以及按照QoS特征划分的四类UMTS接入系统业务，概要讨论了UMTS系统的QoS保证体系结构，着重分析了其结构分层和QoS控制的层间映射／分段保证机制。     

UMTS体系结构研究

基于3GPP IMS的网络架构支持固定网络接入需求和未来网络的各种业务需求,有利于实现未来固定、移动网络在核心业务控制层的共享和融合,并提供对高层多种业务的支持,已经成为下一代网络的发展方向。文章研究了3GPP规范的演进情况,分析了3GPPR5的网络体系结构,给出了相关实体的功能与特点,并介绍了IP多媒体子系统的基本结构。     

W-CDMA/UMTS下一种解决TCP有效性和公平性的跨层方案

在UMTS系统中,由于MAC层的包调度引入了用户间的竞争,带来了传输层TCP有效性和公平性问题,为了解决这个问题,该文提出了一种主动ACK包转发控制策略(AAFC),它的基本思想是在基站处嵌入AAFC模块,通过MAC层和传输层之间的消息传递来控制基站处ACK包的转发,以此来保证用户间TCP流的公平性以及链路层无线资源的最充分利用。仿真结果证明了AAFC方案的有效性。     

Hybrid coupling scheme for UMTS and wireless LAN interworking

We propose a hybrid coupling scheme to support interworking between UMTS and WLAN networks. Under the Tight-coupled system, it is expected that WLAN users can also use UMTS services with guaranteed QoS and seamless mobility. However, the interworking is problematic. The capacity of UMTS core network nodes cannot accommodate the bulky data traffic from WLAN, since the core network nodes are designed to handle the small-sized data of circuit voice calls or short packets. The proposed coupling scheme differentiates the data paths according to the type of the traffic and can accommodate traffic from WLAN efficiently, with guaranteed QoS and seamless mobility. We compare the handover procedures of the proposed coupling strategy with those of the loose and tight coupled schemes. In addition, we analyze the delay based on signaling costs during vertical handover. It is shown that the handover latency decreases when the UMTS and WLAN are coupled in the proposed way.     

浅析中国联通部署UMTS900带来的挑战

UMTS900相对UMTS2100来说,具有一定的技术优势,本文结合中国联通的网络特点,分析中国联通部署UMTS900会给网络带来怎样的挑战以及规划上的难点。