基于空分复用的多信道机间紫外光通信定向MAC协议

为了弥补飞行编队任务分配情况和不同模式下紫外光定向通信存在耳聋问题的缺陷,采用一种基于空分复用的多信道机间紫外光通信定向信道接入协议,建立了机间紫外光通信网络模型。通过在紫外节点安装多个不同方向的紫外收发装置来实现多信道信息交换,并仿真验证了多信道通信使耳聋问题得到明显缓解,提高了网络吞吐量,降低了网络时延,使得网络性能显著改善。结果表明,多信道通信与单信道通信相比,网络吞吐量增加,平均时延减小,网络性能大幅度提高,并且采用三信道通信模式通信效果最佳。     

多路载波光纤通信

本文在追述多路电缆通信技术之后,介绍三种实用的多路光纤通信方式和它们各自的应用。前两种是光载波的波分多路通信(WDM):路数少和间隔大的称为波分多路,用于沿线光放大的长途线路;路数多和间隔小的称为密集频分多路,用于区域光纤网的频分多址(FDMA)通信。第三种是电载波作为副载波的频分多路(SCM),由一个光载波传输,用于光纤有线电视(CATV)广播网。     

一种新的光因特网网络技术研究

近年来,光技术已能把巨大信息流传送很长一段距离,这一成功使高容量波分多路复用(WDM)系统迅速商业化。WDM技术是在同一根光纤上提供许多“虚”光纤,通过不同的频率传输信号,使网络供应商能在一根光纤中传输许多信号,就像每个信号是在各自不同的光纤中传输一样。光技术的使用强烈地依赖于光网络的类型和需求。近来,光通信技术的研究趋势已集中在新的光通信网络结构和宽带光传输技术两个领域。文中在分析研究光因特网网络模型的基础上,提出一种新型混合模型网络结构。模拟仿真研究结果表明,该技术是可行的。     

Frequency tuning characteristics and WDM channel access of thesemiconductor three-branch Y3-lasers

We describe frequency tuning and channel access characteristics of the new, widely-tunable, multi-quantum-well three-branch Y3-lasers. The Y3-lasers are tuned discretely with two independent current controls: coarse tuning (5.5 nm, 680 GHz tuning steps) selects the desired optical frequency range, fine tuning selects the desired frequency channel (0.4 nm, 50 GHz channel spacing). For example, we demonstrate access to 50 channels over the ~31 nm free spectral range of the Y3-laser; 36 contiguous channels are accessed using three independent current controls. The coarse/fine “digital” tuning makes Y3-lasers very useful for wavelength-division-multiplexed (WDM) multi-channel optical communication systems     

A slotted access control protocol for metropolitan WDM ring networks

In this study we focus on the serious scalability problems that many access protocols for WDM ring networks introduce due to the use of a dedicated wavelength per access node for either transmission or reception. We propose an efficient slotted MAC protocol suitable for WDM ring metropolitan area networks. The proposed network architecture employs a separate wavelength for control information exchange prior to the data packet transmission. Each access node is equipped with a pair of tunable transceivers for data communication and a pair of fixed tuned transceivers for control information exchange. Also, each access node includes a set of fixed delay lines for synchronization reasons; to keep the data packets, while the control information is processed. An efficient access algorithm is applied to avoid both the data wavelengths and the receiver collisions. In our protocol, each access node is capable of transmitting and receiving over any of the data wavelengths, facing the scalability issues. Two different slot reuse schemes are assumed: the source and the destination stripping schemes. For both schemes, performance measures evaluation is provided via an analytic model. The analytical results are validated by a discrete event simulation model that uses Poisson traffic sources. Simulation results show that the proposed protocol manages efficient bandwidth utilization, especially under high load. Also, comparative simulation results prove that our protocol achieves significant performance improvement as compared with other WDMA protocols which restrict transmission over a dedicated data wavelength. Finally, performance measures evaluation is explored for diverse numbers of buffer size, access nodes and data wavelengths.     

Supporting bursty traffic with bandwidth guarantee in WDM distribution networks

This paper presents new research results of the DARPA-funded ONRAMP consortium on the next generation Internet to study efficient WDM-based network architectures and protocols for supporting broadband services in regional access networks. In particular, we present new efficient scheduling algorithms for bandwidth sharing in WDM distribution networks. The current ONRAMP distribution network architecture has a tree topology with each leaf node (e.g., a router or workstation) sharing access to the root node of the tree, which corresponds to an access node in the feeder network. Our model allows a leaf node to use one or more fixed-tuned or tunable transceivers; moreover, different leaf nodes can support different subsets of wavelengths depending on their expected traffic volumes. An important goal of ONRAMP is to support bandwidth-on-demand services with QoS guarantee over WDM. As a first step toward this goal, we have developed several fast scheduling algorithms for flexible bandwidth reservations in a WDM distribution network. The scheduling algorithms can provably guarantee any bandwidth reservations pattern that does not overbook network resources, i.e., bandwidth reservation (throughput) up to 100% network capacity can be supported.     

光纤通信技术的现状及发展趋势

简要介绍了我国光纤通信的现状,总结了目前正在使用的波分复用技术和光纤接入技术的基本原理和发展状况,最后从超大容量、超长距离传输技术,光孤子通信技术和全光网络3个方面论述了光纤通信技术的发展趋势.     

基于MIMO技术的WMN MAC协议研究

分析了MIMO技术中由于通信链路间干扰导致网络吞吐量降低的问题,提出了一种基于多模多信道技术的改进MAC协议(MPRP-MAC),利用节点中的多个通信模块以及多个正交信道资源,使节点可以在无干扰的情况下实现接收与发送同时进行。实验结果表明,该技术可充分利用天线资源,有效提高系统容量。     

波分复用技术及其在通信中的应用

波分复用 ( WDM)技术以其优异特征成为对现有光纤传输系统进行扩容、升级改造及建设新的高速、大容量通信网络的优选技术方案。文中阐述了它的主要技术特点 ,着重论述了它在通信领域中的应用 :长途通信干线传输、区域网、接入网等 ,并对 WDM技术的未来发展和应用进行了分析与展望。     

Economic Optical Networking in the Metropolitan Area

The rapid introduction of wavelength division multiplexing (WDM) technology in long distance fiber optic communication networks which has been observed in the recent years has been driven by line economy. Not merely the ability to overcome fiber scarcity, but also the savings associated with the replacement of many electronic regenerators by fewer optical amplifiers, have motivated the carriers to employ WDM. These arguments do not often apply to optical networking in metropolitan areas because transmission distances are short. For this reason, metro-WDM has been deployed in a few rare cases only, though it has been widely discussed by a broad scientific and industrial community. In this paper, an advanced operational concept for all optical transport networks in the metropolitan area is introduced. It focuses on node economy, i.e., the technical concepts to provide gigabit services access to the transport network at minimum cost, characterized by the following basic features: protocol independence, monitoring, protection and fast bandwidth provisioning.     

波分复用技术在实现双向改造中的应用

DWDM和CWDM技术是WDM技术的两种方式,其通过在一芯光纤中传输多路光波来实现光通信网络容量的扩展、提升光信道的利用率。文章通过对DWDM技术优点、技术分类和发展现状的介绍,以及通过对于DWDM和CWDM技术在福州双向网络改造中的应用,来探讨如何在不改变现有光网络结构的基础上,实现网络容量提升,满足用户日益增长的需求。     

40Gbit/s WDM系统可调色散补偿的实现

文章介绍了一种用于40Gbit/s波分复用(WDM)系统的可调色散补偿方案,采用啁啾布拉格光栅的多通道色散补偿技术和掺铒光纤放大器的自动功率控制技术,可以对现有40Gbit/s主流调制编码格式的波分复用系统进行高精度的色散补偿,同时能提高接收机的动态范围.     

一种新型基于MIM等离子体环形谐振器的可调谐高性能多信道波分解复用器的设计

设计并研究了基于金属-介质-金属等离子体环形谐振器的可调谐高性能多通道波分解复用器。通过环形腔的谐振理论分析,发现通过调节环形腔的半径和填充介质折射率可以很容易地控制波分复用器的信道波长,与有限元法模拟得到的结果吻合得很好。由等离子体波导和多个环形谐振器组成的多信道WDM结构增加了在电信波长的传输率,传输率高达80%,比最近文献中报道的结果高出两倍。所设计的多信道波分解复用器在高集成电路中有重要潜在应用。     

A collision-free with propagation latency WDMA protocol analysis

The substantial role of propagation delay latency in WDM networks is examined in this paper in conjunction with a multi-channel control architecture (MCA) that reduces the processing overhead of control information for synchronous transmission in passive star topology. We exploit the peculiarity of propagation delay latency in WDM networks and its impact in the performance measures to introduce a simple multiple access algorithm avoiding data channel conflicts, aimed at improving of system utilization. Also we examine the effect of receiver collisions to performance measures evaluation developing analytic Markovian models for finite population.     

光通信用的多路半导体激光器监控系统研究

依据波分复用（WDM）在光通信中的应用需求,研制了一套多路半导体激光器（LD）监控系统作为通信系统光源。该系统采用USB 2.0高速传输模式,DSP与FPGA构建数字通信单元,以上位机作为监控平台,实现了高效调制多路激光器波长和功率,同步采集多路数据,实时监测各路激光器状态等功能。所研究的LD恒温及LD光功率恒值控制具有良好的控制精度。实验结果表明,在1h内温度稳定性达±0.01℃,功率稳定性达0.5%。     

具有多个波长通道的光纤光栅相位编/解码器

光码分多址(OCDMA)技术是实现未来宽带全光接入网的最佳技术之一.提出了一种基于超结构光纤光栅(SSFBG)的光码分多址时域相位编/解码器.编/解码器根据等效相移原理,采用Sinc函数作为采样函数,仅仅利用一块均匀的相位掩模板即实现了多个性能一致的编/解码信道,可以并行对不同波长通道的用户同时进行编/解码,既节省了成本又提高了系统容量.对该编/解码器的结构和性能进行了分析,并进行了计算机仿真.结果表明,对于使用127位Gold序列的编/解码器,各通道自相关峰瓣比(P/W)大于16.3 dB,峰瓣比波动小于0.4 dB,归一化自相关峰值波动小于0.04,各个编码通道取得了与纯相移编/解码器相近的性能,可用于光码分多址/波分复用(WDM)混合系统.     

一种使用波分复用的室内红外网络

讨论波分复用(WDM)的室内红外通信网络的结构和协议.在该网络中,网络节点可以同时使用多个波长传输数据.该无线传输方式需要一种新的媒体接入控制(Media Access Control,MAC)协议,使得网络节点波长能被动态地分配工作波长.讨论了这种协议的基本工作方式,简要分析了协议的数学模型,并在网络模拟软件NS2中7验证了该协议.通过对验证结果的分析,证明这种室内红外通信网络可以有效提高网络的总流量,提出的媒体接入控制协议是可行的.     

Efficient QoS support in a slotted multihop WDM metro ring

A novel distributed access protocol for a slotted wavelength-division-multiplexing (WDM) metro ring employing all-optical packet switching and supporting quality-of-service (QoS) classes is presented and analyzed. Since we assume that there are more nodes than available wavelengths in the network, we obtain a scalable multihop WDM ring as underlying network architecture. By dividing each channel into several time slots and further applying destination release and slot reuse, data packets can be efficiently transmitted and received in a statistically multiplexed manner. In our architecture, each node is equipped with one tunable transmitter and one fixed-tuned receiver. Furthermore, as we generally consider so-called a posteriori access strategies, different packet selection schemes are proposed and compared. An analytical model based on the semi-Markov process methodology is developed to quantify the performance of one of these schemes. As a key element of the protocol, an efficient QoS support access mechanism is proposed and its performance is evaluated. The new QoS control scheme adopts a frame-based slot reservation strategy including connection setup and termination, which only slightly increases the signaling and node processing overhead. Thus, an efficient hybrid protocol combining connectionless and connection-oriented packet transmissions is proposed     

多路数据光纤传输系统

充分利用光纤的频带资源是降低光纤数据传输系统成本的重要途径,波分复用和时分复用是信道共享和有效利用的常用方法.通常,利用CPLD实现多路信号时分复用的方式较使用多个激光器产生多个波长的激光的波分复用方式有较大的成本优势,但后者更容易实现双向通讯.因此,将波分复用和时分复用结合复用的方式即可实现一种高速、双向,点到点的光纤数据传输系统.     

紫外光非视距通信的定向媒体接入控制协议

对基于紫外光非视距（NLOS）定向发送全面接收通信方式（MAC）协议进行了研究。首先根据紫外光NLOS通信的特点,推导出NLOS通信覆盖范围方位角的表达式;其次根据紫外NLOS通信时路径损耗特点和方位角表达式,对目前紫外NLOS定向发送全向接收的节点结构设计规则进行改进;然后提出一种基于角度感知的紫外光NLOS通信定向...