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1引言 在用户接入网建设中,目前普遍使用的有铜线接入网、无线接入网和光纤同轴混合接入网等,但是,随着网络传输的业务种类越来越多,交互性越来越强,带宽的需求越来越宽,接入网部分的带宽“瓶颈”问题也就越来越突出。从发展的趋势来看,要建成一个数字化、宽带化、综合化、智能化及个人化的用户接入网,最理想的形式当是建成一个以光纤接入为主的用户接入网。 相似文献
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在接入网的建设中,按照光纤尽量靠近用户的规 则,发展以光纤接入网为主的原则,在我国已建成了 1000多万线的光纤接入网,实现了光纤到路边、光纤 到办公楼、光纤到居民小区或居民楼。但在已建成的 光纤接入网中,大多还是基于电路模式的窄带接入网。 其缺点除带宽窄、电路调度不灵活、功能受到限制以 外,还有SM仅仅接入到单一业务的网络节点,或通过 该业务节点转接到其他业务节点,占用了大量的节点 资源。 相似文献
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随着视频点播、网络游戏和IPTV等高带宽业务的出现,用户对高带宽、双向传输能力以及安全性等方面的要求进一步增加,全球都把关注的目光投向了光纤接入网(FTTx),FTTx被视为下一代宽带接入技术的代表. 相似文献
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翟跃 《大气与环境光学学报》2002,(6)
业内人士认为接入网技术发展方向如下:(1)光纤接入网(含光接入网技术)有线接入网在接入网中处于主体地位.全光接入网技术,即光纤到桌面、光纤到家,随着用户对带宽需求的不断增加,将得到不断的发展。(2)综合接入网技术 综合接入网设备同时具备POTS、ISDN、DDN、IP等业务的接入功能,既能降低网络建设成本,又方便网络的统一维护。以后的综合接入网设备将能同时提供各类宽带和窄带业务的接入。(3)接入网宽带化 也是接入网发展的关键、以ATM为基础的无源光网络(APON)可以通过利用ATM的集 相似文献
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居住小区宽带FTTH网络建设技术实施 总被引:1,自引:0,他引:1
光纤到户是宽带接入的一种理想模式,是指从城域网到小区、用户间的最后接入网阶段全部使用光纤,以实现语音、数据、广播电视及各类智能化系统功能的一种接入方式。光纤到户在带宽方面的巨大优势使它成为未来网络接入发展的最终目标,它将最终突破带宽的瓶颈,是实现"三网合一"的最理想的方式。研究通过结合工程实例对光纤到户接入技术设计进行分析。 相似文献
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在接入网的建设中 ,按照光纤尽量靠近用户的规则 ,发展以光纤接入网为主的原则 ,在我国已建成了10 0 0多万线的光纤接入网 ,实现了光纤到路边、光纤到办公楼、光纤到居民小区或居民楼。但在已建成的光纤接入网中 ,大多还是基于电路模式的窄带接入网。其缺点除带宽窄、电路调度不灵活、功能受到限制以外 ,还有SNI仅仅接入到单一业务的网络节点 ,或通过该业务节点转接到其他业务节点 ,占用了大量的节点资源。在因特网发展迅猛的今天 ,窄带接入网已不能满足快速因特网接入和宽带多媒体业务的接入需求。今后接入网在FTTC、FTTO、FT… 相似文献
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Giles R. Tingye Li 《Proceedings of the IEEE. Institute of Electrical and Electronics Engineers》1996,84(6):870-883
Optical amplifiers and wavelength-multiplexing technology are transforming lightwave communications by providing cost-effective upgrades that will increase immensely the transmission capacity of long-distance telecommunications networks. A new generation of undersea cable systems using fiber optical amplifiers as repeaters has been developed for transoceanic applications, yielding a capacity almost ten times larger than conventional systems using opto-electronic regenerators. Terrestrial long-haul networks will benefit significantly from amplified wavelength-multiplexed transmission systems designed to access the large inherent bandwidth in the installed fiber. Successful deployment of these advanced systems requires a thorough understanding of optical amplifiers and the optical fiber medium, as their requirements interrelate through optical bandwidth, noise, dispersion, optical nonlinearities, and their impact on signal transmission. While the first commercial WDM amplified lightwave systems are deployed for point-to-point applications, optical transparency and wavelength multiplexing will be exploited for networking leading to the higher functionality and improved cost-effectiveness expected of photonic networks 相似文献
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The next generation of communication systems will provide consumers with a host of new and improved voice, video, and data services. Rapidly developing wireless radio systems are already contributing to the progress, giving consumers the luxury of tetherless access to telephone conversation, on-line computing, and cable-television. Indeed, wireless access to high quality information and entertainment is quickly becoming a key component of the information superhighway. In that context, optical fiber links, which have the bandwidth for providing users with the service of their choice, are an excellent connecting infrastructure for providing uniform radio coverage in wireless networks. Indeed, fast improving analog FO links will serve such networks well. In this article, we will analyze the requirements for such a system 相似文献
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自由空间光 (FSO)技术作为地下光纤网的补充 ,在提供“最后 1km”宽带接入方面与其他的固定无线设备相比有很强的竞争力。虽然通过空气传输光信号仍然存在技术上的挑战 ,但是与敷设光纤网相比 ,FSO成本低、安装快捷 ;与安装其他固定无线网络相比 ,FSO还具有高速宽带和无需许可的特点 ,具有非常好的应用前景。 相似文献
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Long haul optical networks have been on focus for more than two decades. With the advent of dense wavelength division multiplexing technology, optical long haul fiber networks have been so successful in delivering an unprecedented amount of bandwidth that they outperformed the traffic deliverability from/to the access network by orders of magnitude. The reason was a cost-efficiency mismatch; long haul ultra-high bandwidth networks can take advantage of state of the art and costly technology, which cost-sensitive access networks cannot. The result was an unbalanced traffic flow from/to access points to the network if one compares the aggregate flow of the long haul network with that of the access. Nevertheless, over the last decade technology at the access advanced and new standards have been developed so that in the access layer of the overall communications network the focus has shifted onto fiber optic access again. Thus, in the optical regime, two proposals have prevailed. One uses a time division multiplexing (TDM) scheme over a single wavelength and a comprehensive timing protocol, and the other uses coarse wavelength division multiplexing (CWDM) technology. Each technology has advantages and disadvantages, and the one attempts to address the disadvantages of the other. In this paper we describe a hierarchical CWDM/TDM passive optical network (PON). Our access network architecture is scalable, it is flexible to accommodate one of several topologies simultaneously, and it delivers any type of payload, synchronous and asynchronous that spans from DS0 to Gbps. We discuss the bandwidth flexibility, versatility, resiliency and cost efficiency of the access network. We also demonstrate that our network can deliver payload to more than 16,000 end-users using simple and existing optical technology. Thus, if one considers cost per bandwidth or per user, the cost-efficiency outperforms any previous PON access network. Moreover, we provide simulation results to support the viability of our network architecture. 相似文献
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Knud Erik Skouby Morten Falch Anders Henten Reza Tadayoni 《Wireless Personal Communications》2014,76(2):271-289
The need for broadband capacity in the access networks by 2020 is discussed in this paper. A large range of countries around the world has decided to strengthen their resolve to have their broadband infrastructures built out and upgraded. The size of bandwidth requirements is, however, not an issue, which has been subject to much analysis from an academic angle whereas a number of consultancy reports with estimations on bandwidth needs for different services can be found. The needs for broadband access up until 2020 are discussed by scrutinizing the different services and applications requiring bandwidth. The bandwidth requirements in question are those of residential users and SMEs. In the paper it is assumed that users of broadband connections will use broadband for all their digital communications and further the paper focuses on the requirements for bandwidth notwithstanding the pricing of access. It is the estimated bandwidth need and not the actual demand, which is the subject of analysis. Scenarios including different types of households and different kinds of SMEs are presented. 相似文献
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The fiber-wireless (FIWi) access network not only leverages the technical merits of wireless and optical access networks, but also provides a potential opportunity for the design of survivable access networks. Previous works have studied the survivability of FiWi access network against network component failure by means of backup fiber deployment and wireless rerouting. However, most of these works put less attention on the connection availability and ignore the joint allocation of wireless and optical resources, which plays an important role in improving the global network performance gain. In this paper, we consider a notable failure scenario in FiWi access network but less mentioned in previous works, i.e., single shared-risk link group failure. We first propose a model for FiWi network to estimate the connection availability of service demand. Then, a novel resource allocation approach is proposed to provide the availability-guaranteed service. Under the requirements of bandwidth and connection availability, we deal with the optimal allocation of joint wireless and optical resources with the objective of minimum resource consumption. Numerical results demonstrate that the proposed scheme can reduce the resource consumption significantly compared to the resource allocation without considering connection availability. 相似文献
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Next generation (NG) wireless networks are envisioned to provide high bandwidth to mobile users via bandwidth aggregation over heterogeneous wireless architectures. NG wireless networks, however, impose challenges due to their architectural heterogeneity in terms of different access schemes, resource allocation techniques as well as diverse quality of service requirements. These heterogeneities must be captured and handled dynamically as mobile terminals roam between different wireless architectures. However, to address these challenges, the existing proposals require either a significant modification in the network structure and in base stations or a completely new architecture, which lead to integration problems in terms of implementation costs, scalability and backward compatibility. Thus, the integration of the existing medium access schemes, e.g., CSMA, TDMA and CDMA, dictates an adaptive and seamless medium access control (MAC) layer that can achieve high network utilization and meet diverse quality of service (QoS) requirements. In this paper, an adaptive medium access control (A-MAC) layer is proposed to address the heterogeneities posed by the NG wireless networks. A-MAC introduces a two-layered MAC framework that accomplishes the adaptivity to both architectural heterogeneities and diverse QoS requirements. A novel virtual cube concept is introduced as a unified metric to model heterogeneous access schemes and capture their behavior. Based on the virtual cube concept, A-MAC provides architecture-independent decision and QoS based scheduling algorithms for efficient multi-network access. A-MAC performs seamless medium access to multiple networks without requiring any additional modifications in the existing network structures. It is shown via extensive simulations that A-MAC provides adaptivity to the heterogeneities in NG wireless networks and achieves high performance. 相似文献
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面向高速城域网的新型光纤 总被引:3,自引:0,他引:3
适用于城域网的低成本、高速、大容量接入网的光纤,可满足将来系统设计的要求,WideLight^TM光纤对于城域网的应用是一种极为理想的新型光纤。 相似文献
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Davit Harutyunyan Roberto Riggio Slawomir Kuklinski Toufik Ahmed 《International Journal of Network Management》2020,30(1)
Mobile network operators are currently facing a tremendous increase in the level of data traffic. Although cell size reduction is one of the most common ways used to accommodate such traffic demand, densely deployed small cells also dramatically increase the level of intercell interference. By centralizing baseband signal processing at powerful computing infrastructures, called centralized unit (CU) pools, cloud radio access network (C‐RAN) enables advanced coordination algorithms to be employed in dense small cell networks. In C‐RAN, due to stringent bandwidth and latency requirements at the fronthaul links, the optical fiber, thanks to its bandwidth and latency characteristics, continues to be the most prevalent fronthaul medium option. Nevertheless, the optical fiber is one of the fronthaul options, while C‐RAN (physical layer radio frequency [PHY‐RF] split) is one of the functional splits that can be defined each coming with different fronthaul requirements. In this paper, we formulate and solve a dynamic CU placement problem for mobile networks as an integer linear programming (ILP) problem. In the considered network, CU pools are placed at the edges of the network, and a reconfigurable millimeter wave (MMW) wireless fronthaul links are used in order to provide decentralized units (DUs) with connectivity. We study the impact of different functional splits on the placement cost and on the acceptance ratio using different substrate networks. Lastly, we propose and evaluate a CU placement heuristic algorithm using a numerical simulator. The results reveal that the optimal functional split selection can lead to significant resource utilization benefits in the RAN. 相似文献