第三代移动通信网的Iu接口

Iu接口是第三代移动通信网中无线接入网和核心网之间的接口。它与CDMA IS－95的A接口有非常大的区别。它是一个开放的接口。本文主要介绍了对Iu接口的要求，Iu接口的结构及功能，Iu接口的协议结构及相关的协议。     

3G互操作测试的探讨

互操作测试(IOT)是多厂商运营环境形成的技术基础。只有完成Iu接口的互操作测试，才能保证不同厂家的无线接入网与核心网的互联互通，也只有完成Uu接口的互操作测试．才能保证每一款手机与无线接入系统之间的互联互通。     

TD-SCDMA网络建设中Iu接口用户平面假活现象的解决方法

为了满足用户对网络性能不断增长的需求,3GPP在R4核心网中引入软交换技术,将移动交换中心（MSC）分成移动交换中心服务器（MSCServer）和媒体网关（MG）,并选择Iu接口作为无线接入网（UTRAN）和核心网（CN）的通用接口。主要讨论了在TD-SCDMA网络建设中Iu接口用户面的假活现象对网络性能的影响,并提出了具体的解决措施,包括增加MSCServer对Iu用户面资源的监测功能。利用SNMP协议在MScServer中检测并向无线网元管理器（WEM）卖时反馈Iu接口用户面状态。最后将该方案以系统补丁的形式,在上海贝尔阿尔卡特实验室TD—SCDMA试验网中进行功能验证与测试。     

网通IMS试验网开始预商用TD核心网稳中存变

在目前进行的十个城市TD-SCDMA外场测试中，运营商毫无例外的采用了与WCDMA完全一致的核心网。原因很简单，摩托罗拉网络部庞韶敏介绍：“在核心网方面，TD-SCDMA与WCDMA采用完全相同的标准规范，包括核心网与无线接入网之间采用相同的Iu接口，以及空中接口高层协议也完全相同。”这些共同之处保证了两个系统之间的无缝漫游、切换、业务支持的一致性、QoS保障等，也保证了TD-SCDMA和WCDMA在标准技术的后续发展上保持相当的一致性。     

MSC POOL技术原理及组网分析

Iu/A-Flex技术是在3GPP R5版本中正式提出的一种新的组网机制,其核心是一个无线接入网（RAN）可接入多个核心网（CN）节点,并引入Pool的概念。Iu/A-Flex功能的引入可以实现核心网节点间的负载均衡,提高设备利用率;减少跨局切换信令、降低网络信令负荷、提高网络性能;提供自动容灾机制;方便网络运行维护。这里对基于Iu/A-Flex的POOL原理进行和关键技术进行了分析,并针对在移动核心网现网中引入POOL技术进行探讨。     

第三代移动通信系统和网络有关的问题

本文主要综述了第三代移动通信系统 UMTS 网络方面的问题,包括对 UMTS 的要求,Iu 接口,各种协议结构,第三代移动通信系统的多媒体业务,核心网及无线接口的3层协议结构,移动 IP 及其它无线接入技术。     

第三代移动通信系统和网络有关的问题

本文主要综述了第三代移动通信系统UMTS网络方面的问题,包括对UMTS的要求,Iu接口,各种协议结构,第三代移动通信系统的多媒体业务,核心网及无线接口的3层协议结构,移动IP及其它无线接入技术。     

基于接入点控制器重选的专利技术研究

RNC是无线接入网的管理控制核心,控制无线接入网和核心网的接口,RNC切换技术是移动通信网络中主要技术之一。本文从接入点控制器重选技术专利申请的角度出发,基于专利技术所要达到的技术效果介绍了接入点控制器重选技术的发展。     

cdma2000 1xEV-DO系统中的QoS

本文首先介绍了cdma2000 1xEV-DO空中接口相关协议对QoS的支持,接着分别从无线接入网、核心网、骨干同三个方面讨论了1xEV-DO系统实现QoS的机制,最后指出了当前系统实现QoS面临的问题。     

移动通信网络节能探讨

根据中国电信、中国移动、中国联通三家移动运营商现网的能耗分析结果,移动网络节能的重点在无线接入网部分,其次才是核心网和传送网。文章分别对无线接入网、核心网、传送网节能方案进行探讨,提出无线接入网节能可以从网络拓扑和网元两个层次进行,网元节能从设备、冷却系统及新能源引入等方面着手,核心网和传送网能耗问题可以从架构、设备、机房热管理等层面考虑。     

WLAN层间服务接口设计与FPGA实现

提出一种无线局域网中物理层与媒体访问控制(MAC)层的层间接口设计方案。该方案分别从硬件连线规划、地址分配、层间原语交互操作和层间数据收发等几个方面进行设计,并在FPGA上实现。通过一套完整的无线传输实验平台进行实验验证,结果表明,此接口功能符合IEEE 802.11a协议要求,物理实现简单,可扩展性好。     

抽象语法表示ASN.1及其在TD-SCDMA中的应用

在TD-SCDMA系统中,RRC的消息将采用ASN.1中的PER编码格式来增加RRC消息在空中接口上的传输效率,并且在TD-SCDMA网络侧的Iur、Iub和Iu接口都采用了ASN.1编码格式进行传输.文章将介绍ASN.1的基本知识以及BER和PER的编码规则,并结合如何解析TD-SCDMA消息的方法来具体讲解ASN.1的应用.[1]     

Robust QoS Control for Single Carrier PMP Mode IEEE 802.16 Systems

The IEEE 802.16 WirelessMAN standard provides a comprehensive quality-of-service (QoS) control structure to enable flow isolation and service differentiation over the common wireless network interface. By specifying a particular set of service parameters, the media access control (MAC) mechanisms defined in the standard are able to offer predefined QoS provisioning on a per-connection basis. However, the design of efficient, flexible, and yet robust MAC scheduling algorithms for such QoS provisioning still remains an open topic. This paper proposes a new QoS control scheme for single-carrier point-to-multipoint mode wireless metropolitan area network (WirelessMAN) systems, which enables the predefined service parameters to control the service provided to each uplink and downlink connection. By MAC-PHY cross-layer resource allocation, the proposed scheme is robust against particular wireless link degradation. Detailed simulation experiments are presented to study the performance and to validate the effectiveness of the proposed QoS control scheme.     

Distributed Medium Access Control Next-Generation CDMA Wireless Networks

The next-generation wireless networks are expected to have a simple infrastructure with distributed control. In this article, we consider a generic distributed network model for future wireless multimedia communications with a code-division multiple access (CDMA) air interface. For the medium access control (MAC) of the network model, we provide an overview of recent research efforts on distributed code assignment and interference control and identify their limitations when applied in next-generation wireless networks supporting multimedia traffic. We also propose a novel distributed MAC scheme to address these limitations, where active receivers determine whether a candidate transmitter should transmit its traffic or defer its transmission to a later time. Simulation results are given to demonstrate the effectiveness of the proposed distributed MAC scheme.     

基于A／Iu接口快速割接的网络应急容灾方案

本文首先介绍了网络容灾模型,并分析目前通信网络常用的应急措施,然后提出GSM／UMTS网中A／Iu接口启用多信令点,以实现紧急情况下业务快速割接的技术方案。针对爱立信软交换设备,描述其具体实现步骤。最后根据目前网络状况,提出容灾组网原则及模型。     

Proxy‐RED: an AQM scheme for wireless local area networks

Wireless access points (APs) act as bridges between wired and wireless networks. Since the actually available bandwidth in wireless networks is much smaller than the bandwidth in wired networks, there is a disparity in channel capacity which makes the access point a significant network congestion point in the downstream direction. A current architectural trend in wireless local area networks (WLAN) is to move functionality from APs to a centralized gateway in order to reduce cost and improve features. In this paper, we study the use of RED, a well known active queue management (AQM) scheme, and explicit congestion notification (ECN) to handle bandwidth disparity between the wired and the wireless interface of an access point. Then, we propose the Proxy‐RED scheme, as a solution for reducing the AQM overhead from the access point. Simulations‐based performance analysis indicates that the proposed Proxy‐RED scheme improves the overall performance of a network. In particular, the Proxy‐RED scheme significantly reduces packet loss rate and improves goodput for a small buffer, and minimizes delay for a large buffer size. Copyright © 2006 John Wiley & Sons, Ltd.     

WiMAX宽带无线接入在SDH宽带光城域网的应用模型

WiMAX是一种应用于城域网并提供宽带无线接入的技术。针对我国宽带IP城域网建设的实际情况,结合WiMAX技术优势和应用特点,建立了采用WiMAX接入技术的城域网的网络结构,提出了网络配置方案和各种WiMAX设备的接口要求,并对该应用模型所对应的协议栈进行了分析和设计。对今后WiMAX技术在SDH宽带IP城域网的应用具有实际意义。     

Iu Flex技术研究

对IuFlex的实现原理、关键技术、组网方案进行了详细的定性分析，并分析了IuFlex技术的组网优势和存在的问题，重点研究了引入IuFlex技术后对网络的影响。     

A scalable network-based mobility management framework in heterogeneous IP-based networks

This paper proposes a mobility management scheme to provide a mobile node with high-quality handovers among heterogeneous wireless access networks. The proposed scheme employs a signaling architecture to support fast and reliable delivery of control messages by separating a control plane from a data transport plane in the core network. The proposed scheme is based on the network-based mobility management framework which requires the minimum modifications on terminal devices. With interaction between Layers 2 and 3, the proposed scheme accelerates the handover control procedures. It also enables a mobile subscriber to select a target network for a vertical handover with consideration of not only wireless signal strength but also user preference and quality-of-service status. The proposed scheme addresses the well-known problems of the Mobile IP-based approaches, triangular routing and bottleneck at the home agent, since it establishes a data tunnel for a mobile node along the shortest path between two different access networks. The simulation and experimental results indicate that our scheme provisions more efficient performance than the existing approaches in terms of handover latency, data packet loss, data delivery latency and load balancing.