Link22数据链网络的仿真系统设计

Link22作为新一代链将成为未来战争中的主要装备。介绍了Link22的发展及系统组成,对Link22系统仿真的关键技术进行了讨论,包括:时分多址(TDMA)时隙分配算法、F系列消息、中断时隙接入策略和LNE流程等。利用软件OPNET平台搭建了Link22仿真系统,设计了仿真系统中的网络模型、节点模型和进程模型,并给出了Link22网络性能的仿真结果。     

Design and Dimensioning of a WDM Mesh Network to Groom Dynamically Varying Traffic

In this paper, we address the traffic grooming problem in WDM mesh networks when the offered traffic is characterized by a set of traffic matrices—a variant of dynamically changing traffic. We justify the need to address this problem in mesh networks and also argue for the validity of our approach to solve this problem. Our primary objective is to design the network in terms of the number of wavelengths and transceivers required to support any offered traffic matrix. We provide a simple and generic framework to minimize the number of transceivers needed in the network. Simulation results have been presented in contrast with a possible approach, to enable comparison with our solution strategy. An ILP formulation of our approach is also presented.     

Network Design and Cost Optimization for Label Switched Multilayer Photonic IP Networks

Dealing with the explosive increase in the amount of Internet traffic requires high-speed and huge capacity Internet protocol (IP) backbone networks. Existing IP backbone networks are constructed using point-to-point wavelength-division-multiplexing (WDM) transmission systems, where all the wavelengths are terminated link-by-link, so that rather expensive optical/electrical conversions are necessary at every node. In these systems, since every IP packet is routed at each intermediate node based on the header information, a header processing bottleneck will occur when the node input traffic exceeds several hundreds of gigabits per second. In order to mitigate these problems, an optical cross-connect (OXC) function that employs wavelength routing of the optical paths (OPs) will provide an effective solution. This paper proposes a network design method where electrical and photonic multiprotocol label switching (MPLS) technologies are used; the network is referred to as a photonic IP network. We first propose new algorithms that minimize the network cost in a multilayered network comprising electrical label switched paths (LSPs) and optical LSPs (optical paths that are controlled using the MPLS mechanism). The particular point of the proposed algorithms is that they include different cost minimization scenarios appropriate for the different OLSP provisioning conditions that are chosen as the first step in the design stage. The effectiveness of the proposed algorithms and the benefits of the OLSPs are quantitatively evaluated through various simulations.     

无线传感器网络中数据链路层和网络层设计

作为无线通信网络的一个新的研究热点,无线传感器网络正以其独有的特点和全新的应用而得到人们的广泛关注.本文简要介绍无线传感器网络的体系结构、节点构成和协议层次.分类阐述了几种典型的数据链路层和网络层的设计方案和设计思想.数据链路层中MAC协议可分为两大类:基于竞争的MAC协议和基于预约的MAC协议;网络层的路由算法也分为两大类:平面路由协议和分级路由协议.最后提出一些研究构想.     

A Methodology for Network Topology Design with Link and Node Failures Tolerance

This article describes a new methodology for network topology design considering the problems of single link-failure and single node-failure tolerances.     

Pyxos嵌入式网络中链路电源模块的设计

为了降低Pyxos嵌入式网络的成本、占用空间和使用的复杂性,介绍了链路电源技术在Pyxos嵌入式网络中的应用。利用电源变压器、整流滤波电路、稳压电路和直流电源滤波器所设计的链路直流供给电源模块向网络供给24V直流电;利用交流滤波电路和电源变压器所设计的链路交流供给电源模块向网络供给24V交流电。链路节点电源模块采用低通滤波器将同一电缆同时传输电源信号和数据信号的电源信号输入Pyxos节点并通过线性电源电路向Pyxos芯片提供3.3V的工作电压。为保证网络性能可靠,还提出了确定Pyxos节点与链路供给电源模块的距离的方法。实际应用表明链路电源技术降低了设备的安装时间和成本。     

基于CC—Link现场总线网络的监控系统设计

介绍了CC-Link现场总线技术在工业蒸汽锅炉的给水系统的成功实现。阐述了CC-Link现场总线结构特点及其通讯原理,并结合工业燃煤蒸汽锅炉给水系统的特点介绍系统中基于CC-Link总线构建的锅炉给水系统的监控网络,及其基本硬件配置和软件结构。详细介绍了利用变频器控制给水电机工作原理和采用触摸屏作为监控系统控制界面设计方案实现。     

基于E1链路的远程内部网设计

讨论一种基于E1链路的总线式组网方式,以及在此E1链路上直接采用时隙复用技术的远程企业内部网网络设计方案。针对具体应用讨论了E1链路的动态时隙分配策略。     

Photonic Impulse-Radio Wireless Link at $W$-Band Using a Near-Ballistic Uni-Traveling-Carrier Photodiode-Based Photonic Transmitter-Mixer

A $W$-band photonic transmitter-mixer, constructed by integrating a planar quasi-yagi radiator for feeding the WR-10 waveguide-based horn antenna and a near-ballistic uni-traveling-carrier photodiode, is used with a mode-locked fiber laser to obtain 2.5-Gb/s impulse-radio (IR) wireless data transmission at around a center frequency of 100 GHz. The bias-modulation technique provides less jitter and a longer maximum transmission distance compared with the technique of modulating the optical pulse train using an electrooptics modulator. Using the bias-modulation technique, we achieve a 2.5-Gb/s IR wireless data transmission.      

基于IPv4/IPv6混合网中BRT立体交叉网设计实现

结合NAT-PT和IVI技术实现了纯IPv4网络和纯IPv6网络的互通,同时为了实现IPv4/IPv6混合网络与IPv6网络间快速通信,提出了一种BRT立体交叉网系统模式。该模式在IPv6网络和双栈网络间搭建高架BRT快速IPv6通道,使IPv6通过BRT高架专用IPv6通道进行通信。实现了在实验网络中混合网络和IPv6网络快速通信,解决了由于IPv6在双栈网络中占用IPv4的通信通道,增加网络负担,影响网络通信问题。     

60-GHz Photonic Millimeter-Wave Link for Short- to Medium-Range Wireless Transmission Up to 12.5 Gb/s

In this paper, a 60-GHz photonic millimeter-wave link system for short- to medium-range broadband wireless data transmission is investigated. The system employs advanced mm-wave photonic components and radio-over-fiber (RoF) techniques for the generation of a DSB-SC optical mm-wave carrier and its subsequent on-off-keying modulation and transmission. For short-range applications, we have constructed a compact wireless RoF transmitter consisting of a high-frequency photodiode and a mm-wave antenna only. This system achieved error-free ($hbox {BER}=10^{-9}$, $2^{31}-1$ PRBS, NRZ) in-door transmission of 12.5-Gb/s signals over wireless distances up to 3.1 m with a receiver sensitivity as low as $-$ 45.4 dBm . For fixed wireless access (FWA) requiring a bit error rate of $10^{-4}$, the maximum transmission distance for 12.5 Gb/s is increased up to 5.8 m. For medium-range broadband wireless transmission an electrical radio-frequency (RF) amplifier was employed in the RoF transmitter. Here we achieved 7.5-Gb/s error-free transmission in out-door line-of-sight experiments over wireless distances of up to 36 m. Based upon the experimental results, we expect that the maximum wireless distance the system could accommodate for 12.5 Gb/s is in the kilometer range when using high-gain antennas and an RF transmitter amplifier with a sufficient bandwidth.      

TTE网络混合业务调度器设计和实现

分析了AS6802标准中支持的多种业务消息的传输特性,设计了一种时间触发以太网多种业务消息发送的混合业务调度器。采用发送计划表和允许发送帧长控制,实现了时间触发数据的按时发送。基于允许发送帧长控制和非抢占优先级调度的非时间触发业务发送,保证了带宽利用率,实现了PCF业务的事件触发特性、RC业务的速率限制特性和BE业务的尽力而为特性。混合业务调度器满足了时间触发以太网多业务传输要求。     

Sparse Regeneration in Translucent Wavelength-Routed Optical Networks: Architecture,Network Design and Wavelength Routing

In this paper we study an alternate network architecture, called translucent network, to the fully transparent and fully opaque network architectures. In a translucent wavelength-routed optical network, a technique called sparse regeneration is used to overcome the severe lightpath blocking due to signal quality degradation and wavelength contention in a fully transparent network while using much less regenerators than in a fully opaque network. In this paper, we present a node model and a network model that perform sparse regeneration. We address the problem of translucent network design by proposing several regenerator placement algorithms based on different knowledge of future network traffic patterns. We also address the problem of wavelength routing under sparse regeneration by incorporating two regenerator allocation strategies with heuristic wavelength routing algorithms. We compare the performance of different regenerator placement algorithms and wavelength routing schemes through simulation experiments. The benefit of sparse regeneration is quantitatively measured under different network settings.This work was supported by NSF grants (ANI-0074121 and EPS-0091900).Portions of this work have appeared in the Proceedings of the OSA Optical Fiber Communications (OFC 1999) Conference [6] and the Proceedings of the IEEE Global Telecommunications (GLOBECOM 2001) Conference [12].     

双向HFC网络中光链路设计的热点问题

模拟广播电视的光链路在中国十年前已开始使用,在设计、施工和调试中积累了丰富的经验。 但在当前包括数据传输和交换的有线电视宽带网中,光链路的某些设计原则与以前有所不同,甚至存在一些误区,需要加以澄清,以免走弯路,造成人力和财力的浪费。     

基于51单片机的网络连接控制器设计

介绍了基于51单片机的网络连接控制器的软硬件设计方案，主要采用Atmel公司的8b单片机AT89C51作为核心处理器，采用RealTek公司的RTL8019AS芯片接入以太网。同时讨论了精简的TCP／IP协议栈的分层次实现，实现了可靠的UDP数据通信。     

新型光链路设计在HFC网络中的应用

以往的有线电视HFC光链路设计中,一般的步骤是由下而上,这种设计可以让光发射机的光功率得到最大利用,但缺点也很明显.而采用新型的由上而下的设计:先选定光发射机和光分路器,再计算出各光分路器的传输距离,再将距离相近且地理位置相近的光点接到同一个光分路器,有利于维护和管理,扩展更容易,可组成N 1冗余备份.     

一种基于连通矩阵的Link16网络设计方法

Link16是美军为适应联合作战的需求而研制的新型数据链,技术上,Link16采用了时分多址的接入方式,使用之前需要进行网络设计,即根据作战计划为网络中的每个平台预先分配适合通信需求的发射时隙和中继时隙等参数。网络设计是Link16应用的开始和关键,详细讨论了Link16的网络设计,给出了网络设计需求,并基于缺省连通矩阵,提出了一种简单、灵活的网络设计方法。该方法既能设计出满足通用信息交换需求的Link16网络,也能通过修改缺省连通矩阵,设计出满足特定作战需求的Link16网络,具有较强的实用价值。     

卫星通信链路优化设计

对于卫星通信系统来说，其空间段的成本是系统运营过程中的主要开销，如何更加有效地使用卫星转发器，有效地降低地面设备成本．提高系统工作的可靠性，使系统简单易用，是卫星通信系统设计中最重要的工作。保证空间段资源高效利用和尽可能地减小天线口径／高功率放大器的输出功率．是保证系统性价比的两个重要设计原则。     

无线ATM网络的逻辑链路控制技术

无线ＡＴＭ网络中，在信元进入ＡＴＭ网络层前，须通过逻辑链路控制（ＬＬＣ）层来消除无线信道的影响。本文对使用不同数据包长度和不同ＡＲＱ技术的ＬＬＣ方案进行了比较，并折中考虑了实现的复杂程度与所获得的性能，得出在不同的条件下应使用的数据包长度。本文还仿真了在瑞利衰落环境采用传统ＡＲＱ和码组合ＡＲＱ技术时系统的性能，结果表明码组合ＡＲＱ为一种简单而有效的方法。     

Orthogonal Hybrid Waveguides: An Approach to Low Crosstalk and Wideband Photonic Crystal Intersections Design

A low crosstalk and wideband photonic crystal (PC) waveguide intersection design based on two orthogonal hybrid waveguides in a crossbar configuration is proposed. The finite-difference time-domain (FDTD) and coupled-mode theory (CMT) methods are used to simulate the hybrid waveguides of square lattice. The bandwidth (BW) and crosstalk of the intersection are investigated for various radii of the coupled cavities. It is shown that simultaneous crossing of the lightwave signals through the intersection with negligible interference is possible. The transmission of a 200-fs pulse at 1550 nm is simulated by using the FDTD method, and the transmitted pulse shows negligible crosstalk and very little distortion.