异构云无线接入网络:原理、架构、技术和挑战

为了缓解密集异构无线网络节点间严重的干扰,提高节点间分布式协作处理增益,同时解决云无线接入网络控制信息传输复杂、无法和已有移动通信网络融合等问题,提出了异构云无线接入网络(H-CRAN)作为5G移动通信系统的接入网解决方案.所提H-CRAN的核心是将云无线接入网络与密集异构无线网络融合,将控制平面功能从云无线接入网络中抽离,通过已存的异构大功率节点实现控制平面功能和全网的无线覆盖,利用无线射频单元实现热点区域海量业务的大容量传输.介绍了H-CRAN的系统架构、关键技术组织和研究技术挑战等.     

无线蜂窝网络中的抗干扰以及越区切换

移动互联网的快速发展,使得人们对于无线蜂窝通信网络的性能提出了更加严苛的要求.在这种情况下,微微蜂窝基站、毫微微蜂窝基站等小功率基站的出现,使得无线宏蜂窝网络逐渐转变为新兴的异构无线网络,不仅基站的密度有了很大的增加,网络结构也越发复杂,加上有限的频率资源,使得网络的抗干扰和越区切换问题受到了广泛关注,针对这两个问题,本文开展了相应的研究.     

Avago新品剑指小型蜂窝基站市场

Avago Technologies近日宣布推出面向宏蜂窝和小型蜂窝基站以及便携式GPS系统应用设计的多款新无线应用产品。"受到无处不在连线需求和蜂窝通信高度增长的带动,微型蜂窝(picocell)和毫微型蜂窝(femtocell)基站可以减轻由宏蜂窝和小型蜂窝基站组成异构网络中宏蜂窝的负担。"Avago公司无线应用产品经理Allen Chien指出,"凭藉我们领先业内的手机和基站应用产品和技术,Avago推出了通过集成先前必须由外加芯片提供的功能,带来更高性能并简化系统设计的新产品,从而     

论C-RAN下的5G无线接入网架构

结合我国实际通信情况可知,基于4G网络无线接入网的蜂窝结构已经无法满足用户的高密度通信需求.在布设5G无线接入网的过程中,可利用C-RAN替代原本的蜂窝结构.本文从5G的网络需求入手,对C-RAN下的5G无线接入网结构进行分析.     

IXIA推出新型LTE小型蜂窝验证解决方案

近日,全球领先的融合IP和无线网络测试解决方案提供商IXIA宣称,推出用于验证LTE小型蜂窝系统的新型测试解决方案。IXIA的IxCatapult测试解决方案能够确保LTE毫微微蜂窝、微微蜂窝和微蜂窝的高性能、复原能力和品质。小型蜂窝为低功率的无线接入点,以授权频谱工作,能够将标准的移动设备连接到移动运营商的网络中。毫微微蜂窝和微微蜂窝可为客户和运营商带来诸多潜在益处,包括提高性能、加大覆盖范围以及从拥挤的宏蜂窝中卸载流量。     

基于C-RAN的5G无线接入网架构

在分析传统蜂窝结构的无线接入网面临越来越多的挑战的基础上,介绍了当前移动通信系统的发展趋势和需求,分析了第五代移动通信系统(5G)的研究目标以及对未来网络的要求.针对该问题,提出了基于C-RAN的新型5G无线接入网架构,并进一步阐述了5G通信系统网络架构的潜在关键技术,包括UND、虚拟化,SDN、NFV、CDN和绿色通信,为5G网络架构研究提供参考.     

WWAN和WLAN融合中的移动性管理

随着移动通信的发展，3G业务在国外的蓬勃开展，我国的3G应用时代也即将到来。3G系统可以在更大的覆盖范围内提供语音和数据业务。用户对高数据速率的需求可以通过部署分层结构，如宏蜂窝、微蜂窝、微微蜂窝来实现。在小范围内，宏蜂窝和微微蜂窝可以提供额外的容量，代价是增加基站。使用小区分割和MIMO、OFDM等技术可以提高容量。另一方面，无线局域网可以提供很高的数据速率，     

实现低成本、低功耗无线异构网络——仔细选择HetNet小型蜂窝架构类型,帮助设计人员满足成本、功耗目标

为了解决移动数据和视频流量的爆炸性增长,无线基础设施市场正在迅速向一种新型异构网络(Heterogeneous,HetNet)架构方向发展,一种新的低功耗节点(Low Power Node,LPN)如小型蜂窝、低功耗远程射频头和中继设备的出现弥补了传统宏蜂窝的不足。与此同时,移动运营商不断追求更低的资本支出(Capital Expenditure,CAPEX)和运营成本(Operating Expense,OPEX)成本推动传统的宏蜂窝向"零空间"架构方向发展,如紧凑型基站、有源天线和全室外微波/毫米波无线。     

5G异构网络融合关键技术探究

在5G系统中,异构网络融合能够充分利用不同类型网络的优势,为用户提供多样化的接入手段、通信方式和网络服务。然而,不同类型的无线网络在融合过程中不可避免地会出现一些问题,如移动性管理、无线资源管理、服务质量等,这就给5G异构网络融合提出了新的挑战。基于此,本文围绕5G异构网络融合相关问题进行研究,探究改善5G异构网络融合效用亟待解决的一系列关键技术问题,为5G的规划部署和推广应用提供技术支撑。     

xSON：LTE时代网络质量的最佳保障

xSON是阿尔卡特朗讯倡导的HLN高效能网络的重要组成部分,是对SON的进一步延伸。全球的移动通信网络正在持续演进,从2G到3G,再到今天备受关注的LTE。网络的演进为运营商的业务开展提供了持续动力,但是同时,网络的演进也使得网络的结构更加复杂,对于运营商的运营能力提出了更高的要求。在LTE网络中,网络结构变得更加复杂,不仅有宏蜂窝网络,还有微蜂窝、微微蜂窝、HeNB（家庭基站）等,构成了多层次的异构网络。     

Analogy between data networks and electric networks

It is shown that two fundamental laws, Ohm's law in electric circuits and Little's theorem for queueing systems, are highly analogous. For both single nodes and networks, there is a striking equivalence between the two laws that facilitates the teaching and understanding of the related concepts of current flow in a resistor network and data flow in a communication network     

Mesh networks: commodity multihop ad hoc networks

In spite of the massive efforts in researching and developing mobile ad hoc networks in the last decade, this type of network has not yet witnessed mass market deployment. The low commercial penetration of products based on ad hoc networking technology could be explained by noting that the ongoing research is mainly focused on implementing military or specialized civilian applications. On the other hand, users are interested in general-purpose applications where high bandwidth and open access to the Internet are consolidated and cheap commodities. To turn mobile ad hoc networks into a commodity, we should move to more pragmatic "opportunistic ad hoc networking" in which multihop ad hoc networks are not isolated self-configured networks, but rather emerge as a flexible and low-cost extension of wired infrastructure networks coexisting with them. Indeed, a new class of networks is emerging from this view: mesh networks. This article provides an overview of mesh networking technology. In particular, starting from commercial case studies we describe the core building blocks and distinct features on which wireless mesh networks should be based. We provide a survey of the current state of the art in off-the-shelf and proprietary solutions to build wireless mesh networks. Finally, we address the challenges of designing a high-performance, scalable, and cost-effective wireless mesh network.     

Global networks

The author discusses the global network for international communications being constructured by Cable and Wireless Ltd., entitled the Global Digital Highway (GDH), which will provide a digital, fiber-optic link connecting major commercial and financial centers around the world. He suggests that the world is waiting for basic global facilities that will be exclusively dedicated to facilitating international communications and networking. He examines the trend toward liberalization in telecommunications policies, led by the US, which has recently been joined by both the UK and Japan. He discusses the role of Cable and Wireless in the context of these liberalization policies     

Circulator-capacitor networks

It is shown how filters requiring floating inductance and constant-resistance allpass networks may be made with loss-less circulators and capacitors; the filters, if matched in the passband, are insensitive to small changes in the capacitances.     

Metropolitan-area networks

Metropolitan-area networks (MAN), which fill the gap between local area networks (LANs) and wide-area networks (WANs), are discussed. MANs were originally oriented toward data, but now often carry voice and video traffic as well. Supplying more bandwidth than LANs, they support two-way communication over a shared medium such as an optical-fiber cable, and may offer point-to-point high-speed circuits or packet-switched communication. The two most favored topologies, double-star and double-ring, are described and emerging MAN protocols are examined