无线数字家庭组网技术研究

系统介绍了无线数字家庭组网技术的研究现状和关键技术．对无线数字家庭组网的物理层和媒体接入控制层的相关技术进行了研究．给出了不同关键技术的主要解决方案并且探讨了无线个域网（WPAN）和其他网络共存时的异构组网技术等。     

下一代无线接入网--基于IP的无线接入

下一代无线网络的体系结构标准正在制定中,本文介绍了一种基于IP的网络体系结构,它可以作为不同接入技术的通用接入网。这种基于IP的无线接入网采用Intemet标准和Mobile IP协议支持移动终端的宏移动,当移动终端只做微移动或需实现无线呼叫功能时,就采用HAWAII协议。在网络部署规模日益增长的情形下,基于IP的无线接入在网间互连互通等方面表现出了明显的优势。     

无线接入网及其应用

无线接入网及其应用郑荣良何为“无线接入”？从交换接点到用户终端，如果部分或全部采用了无线方式，就称为无线接入。无线接入的含义很广，它包括移动无线接入和固定无线接入两种。通常的无线接入是指固定用户以无线的方式接入到固定电话网的交换机，即固定无线接入，又...     

无线数字家庭娱乐研究

对数字家庭及娱乐系统的内、外部网络进行了介绍,重点阐述了在数字家庭及娱乐无线化的过程中可采取的模式,提出了改进型无线家庭网关、3G家庭无线网关、嵌入式家庭无线网关3种家庭无线网关形式及其结构,为数字家庭及娱乐的无线化进程提供了思路和方法。     

无线Mesh网络与IEEE802系列标准

无线宽带接入系统发展迅速,但带宽容量低、覆盖范围小等缺点限制了它的进一步发展。作为“最后一公里”宽带无线接入非常重要的技术之一。无线Mesh网络（WMN）可以和多种无线网络系统,如无线局域网（WLAN）、无线个域网（WPAN）以及无线城域网（WMAN）等相结合,改善无线网络的性能,提高网络的覆盖范围。随着无线Mesh网络技术的厂泛应用,IEEE802的相关标准组正在致力于推动WMN技术的发展,制订相关的技术标准。目前,WMN标准已经出现在IEEE802．11s、80215、802．16、802．20中。     

无线接入技术的应用

从电信部门的业务提供点（如交换机,CATV中心）到用户之间的网络称作用户接入网,而无线接入是完成用户接入网的一种重要的接入方式。无线接入技术也称无线接续技术,或称无线本地环路（WLL）,其主要功能是以无线技术为传输媒介向用户提供固定或移动终端的业务。无线本地环路为有线接入提供了一种应用形式灵活、系统经济可靠、实现方便、维护简单的通话方案。因此,无线接入技术受到各国电信业的高度重视。一、国内无线接入技术选用及频率使用应注意的问题1．设备选型上要因地制宜,适度超前无线接入采用的技术多种多样,应用形式五花…     

基于IMT——2000的无线IP体系结构

本文介绍了3GPP2组织提出的基于IMT-2000的第三代移动通信系统的无线IP体系结构、其中主要包括分组数据服务描述，功能模型、网络体系结构和协议参考模型，利用了两种接入方法，简单IP和移动IP，实现了无线分组数据服务。     

IPv6无线传感器网络的研究及其应用

将IPv6与无线传感器网络技术结合起来的IPv6无线传感器网络引起了越来越多国内外研究机构与组织的重视。为了实现IPv6技术与无线传感器网络技术的完美融合,需要全面设计新型的无线传感器网络体系结构。文章充分考虑IPv6以及无线传感器网络的技术特点,提出IPv6无线传感器网络体系结构,并开发出一套适用于大规模无线传感器网络应用的嵌入式IPv6微型协议栈,在此基础上,根据实际应用需求,给出IPv6无线传感器网络与Internet互联的两种不同方式,并给出一个在精准农业生产中典型应用实例。     

移动宽带无线接入技术前瞻

宽带无线接入技术能够通过无线的方式，以与有线接入技术相近的数据传输速率和通信质量接入核心网络．并且有些宽带无线接入技术(如IEEE 802．11系列)支持用户终端构成小规模的具有无中心、自组织、动态拓扑、多跳路由等特性的Ad Hoc网络，因此宽带无线接入技术在高速Internet接入、信息家电联网、移     

超宽带无线技术呈现良好的发展前景

超宽带无线技术（UWB）起源于20世纪60年代对时域电磁学的研究，最初主要应用于军用的雷达高精度测距、测角和隐秘通信。90年代以来，随着现代信号处理技术和集成电路的迅猛发展，使超宽带技术在商业民用领域的广泛应用成为可能。在日前召开的2006全球WiMedia高峰会议上，专家们纷纷认为，这项技术在短距离高空间容量高速无线接入系统应用中、在高速WPAN（数字家庭影视网络）应用中、在短距离高速无线连接应用中，呈现出良好的发展前景。     

Radio-over-Fibre access for sustainable Digital Cities

Pervasive broadband access will transform cities to the net social, environmental and economic benefit of the e-City dweller as did the introduction of utility and transport network infrastructures. Yet without action, the quantity of greenhouse gas emissions attributable to the increasing energy consumption of access networks will become a serious threat to the environment. This paper introduces the vision of a ‘sustainable Digital City’ and then considers strategies to overcome economic and technical hurdles faced by engineers responsible for developing the information and communications technology (ICT) network infrastructure of a Digital City. In particular, ICT energy consumption, already an issue from an operating cost perspective, is responsible for 3 % of global energy consumption and is growing unsustainably. A grand challenge is to conceive of networks, systems and devices that together can cap wireless network energy consumption whilst accommodating growth in the number of subscribers and the bandwidth of services. This paper provides some first research directions to tackle this grand challenge. A distributed antenna system with radio frequency (RF) transport over an optical fibre (or optical wireless in benign environments) distribution network is identified as best suited to wireless access in cluttered urban environments expected in a Digital City from an energy consumption perspective. This is a similar architecture to Radio-over-Fibre which, for decades, has been synonymous with RF transport over analogue intensity-modulated direct detection optical links. However, it is suggested herein that digital coherent optical transport of RF holds greater promise than the orthodox approach. The composition of the wireless and optical channels is then linear, which eases the digital signal processing tasks and permits robust wireless protocols to be used end-to-end natively which offers gains in terms of capacity and energy efficiency. The arguments are supported by simulation studies of distributed antenna systems and digital coherent Radio-over-Fibre links.     

浅析下一代移动通信网络的安全问题

随着移动通信网络的不断发展,无线接人技术、终端技术、网络技术和业务平台技术正向异构化、多样化和泛在化的趋势发展。下一代移动通信网络具有开放、灵活、可管理、移动的网络架构特点,因此其安全问题将比以往移动通信系统更加复杂。文章从下一代移动通信网络的组网结构人手,结合第二代及第三代移动通信系统存在的安全问题,分析下一代移动通信网络所面临的安全威胁,论述了其应具有的安全体系结构。     

面向普适计算的虚拟现实在智能家居中的应用

随着面向普适计算的虚拟现实（U-VR）和无线传感器网络等相关技术的发展,面向应用的智能家居系统的研究逐渐成为关注的热点。本文在此背景下,提出一种基于传感器网络,面向普适计算的虚拟现实在智能家居中的应用方案,并从系统架构、整体设计、硬件设计及软件设计等方面详细阐述了其设计流程。最后给出两个应用场景测试平台,验证了其有效性、实用性和先进性。     

IPv6-based dynamic coordinated call admission control mechanism over integrated wireless networks

Many wireless access systems have been developed recently to support users mobility and ubiquitous communication. Nevertheless, these systems always work independently and cannot simultaneously serve users properly. In this paper, we aim to integrate IPv6-based wireless access systems and propose a coordinated call admission control mechanism to utilize the total bandwidth of these systems to minimize the call blocking probabilities, especially the handoff call dropping probabilities. First, we propose an integrated hierarchical wireless architecture over IPv6-based networks to combine the wireless access systems including cellular systems (second-generation, General Packet Radio Service, or third-generation), IEEE 802.11 a/b/g WLAN, and Bluetooth. In the proposed architecture, mobile user can request a call with quality-of-service (QoS) requirements by any wireless network interfaces that can be accessed. When the proposed coordinated call admission control (CCAC) mechanism receives a request, it takes the QoS requirements of the incoming call and the available and reserved bandwidth of this wireless system into consideration to accept or reject this request. Besides, the mechanism can coordinate with other wireless systems dynamically to adjust the bandwidth reserved for handoff calls at each wireless system in this architecture so as to reduce the call blocking probabilities. Once the call is admitted, the mobile user is able to access heterogeneous wireless access networks via multiple interfaces simultaneously. Finally, we evaluate this system to show that the CCAC on the proposed architecture outperforms other mechanisms proposed before.     

A survey of Mobile IP in cellular and Mobile Ad-Hoc Network environments

The Internet has become ubiquitous and there has been tremendous growth in wireless communications in recent years. Many wireless communication techniques are commercially available, such as the Wireless LAN, Bluetooth, GSM, GPRS and CDMA. Because an all-IP network will be a trend, access to the Internet via wireless communication devices has become an important issue.To reduce power consumption and reuse the limited radio spectrum resources, a cellular network was formed. Cell size is one of the factors in the channel reuse rate. Basically, the channel reuse rate in a smaller cell size is higher than the channel reuse rate in a bigger cell size. Micro-mobility is therefore the inevitable direction for future mobile systems. Frequent and fast movements usually characterize micro-mobility. A cellular architecture would then present a challenge to the frequent handover procedures for a smaller cell size would usually induce a higher handoff frequency.In addition to cellular networks, the ad-hoc network is another network architecture for wireless networks. The ad-hoc network is a non-infrastructure architecture; in which nodes can access services from one another regardless where they are. An excellent routing protocol is crucial for an ad-hoc networking to function at high performance. The main difference between a cellular environment and ad-hoc network is that the ad-hoc method has no fixed infrastructure, allowing nodes to communicate with one another at any time and anywhere.We have mentioned that micro-mobility in a cellular environment would introduce a greater number of handoffs than before. The handoff probability drives the mobile IP mechanism due to signal changes. Using the Mobile IP mechanism, handoff breaking would take place within a micro-mobility environment. Therefore, in this paper, some handoff strategies that take the advantage of the ad-hoc mechanism to improve the handoff performance are investigated.     

An Access Selection Functional Architecture for Heterogeneous Multi-Mode Terminals

The convergence of heterogeneous wireless networks is an inevitable trend in broadband wireless communications development. In heterogeneous networks convergence environment, each wireless network can provide ubiquitous, best Quality of Service (QoS) services. The challenge lies in the design of the management system and access selection architecture for heterogeneous multi-mode terminals. A type of management architecture for heterogeneous multi-mode terminal via effective interaction with all protocol layers is adaptable for multi-access standards and technical requirements to achieve seamless access and mobility for multi-mode heterogeneous terminals. As the core subject for research, access selection functional architecture mainly consists of three modules, namely access adaptation, mobility management, and user preference.     

探测通信一体的自组织泛在无线网络体系架构探讨

针对跨平台协同共享的网络中心体系化协同作战要求,文中瞄准海上无线网络体系建设宏观要求,结合当前无线网络技术、频谱分享、孔径综合和探通一体技术发展成果,提出探通一体的自组织泛在无线网络体系框架设想,从网络架构和拓扑、终端接入能力、定向组网技术、无线资源分配、QoS 管理、多域资源跨层调度优化、网络安全等方面,分析了技术挑战和可能的实现途径,展望了预期成效和应用前景。     

6G:继续体系结构的变革

6G将是5G无线移动通信体系结构变革的延续与深化。以增强宽带与万物互联为应用驱动的网络,必然会从陆地蜂窝移动通信网向全域接入的无线通信网发展。5G开始了移动通信体系结构的变革,但还无法满足未来需求,因此它仅是变革的开端,需要不断改进。在全域接入的无线通信网中,有诸多全域接入架构技术需要6G去探索。     

Traffic load metrics for multihomed mobile IP and global connectivity

Support for host mobility an essential and necessary feature for roaming users who connect to wireless networks via access points. Access points may have different capabilities, be connected to different networks and be installed by different providers. A mobile host will discover multiple access points in this environment. In such an environment, a mobile host should be able to use the best available connection to communicate with a correspondent host and perhaps use multiple connections for different hosts. In areas with wireless local area network access, pockets with limited or no coverage could exist. Such restricted connectivity could be compensated by neighbor hosts who form an ad hoc network and relay packets until they reach an access point. This paper describes and discusses a proposed solution towards enabling and supporting connectivity in wireless networks. In the proposed solution the network layer software will evaluate and decide which wireless network connections to use. A Running Variance Metric (RVM) and a Relative Network Load(RNL) are used to measure the traffic load of access points in wireless access networks. RVM and RNL can be efficiently used for both infrastructure networks and ad hoc networks. Multihomed Mobile IP (M-MIP) is an extension of Mobile IP that enables mobile hosts to use multiple care-of addresses simultaneously. The extension enhances network connectivity by enabling the mobile host, the home agent and correspondent hosts to evaluate and select the best connection. A proposed gateway architecture using M-MIP that integrates wired IP networks with ad hoc networks is described. The M-MIP and gateway architecture using the RVM and RNL metrics have been validated with simulation studies and results are presented.     

ADSL宽带接入系统的研制

目前,ADSL是xDSL中最受关注的宽带接入技术,它的优点是以广泛分布的双绞线为接入媒介,同时它可以利用点到点网络结构给组网带来很大的灵活性.本文以ADSL系统研制为基础,介绍了采用ATM over ADSL结构时宽带接入系统的构成,重点介绍了该方式下ADSL局端线路卡和用户端系统的软、硬件实现.