Flexible synchronous broad-band subscriber loop system: opticalshuttle bus

A flexible, synchronous, broadband subscriber loop system called the optical shuttle bus is discussed. The emphasis is on the proposed design architecture and performance of a 1.8-Gb/s prototype system. The optical shuttle bus is constructed of multigigabit/second intelligent optical shuttle nodes (OSNs). The software-defined OSNs allow the bus to be configured as a synchronous transmission network with any topology and provides flexible channel allocation by means of a drop/insert/cross-connect function. The OSN can be configured as a highly reliable network by virtue of its self-healing functions such as line switch, bypass, and loop back. The proposed bus architecture has been successfully applied in a 1.8-Gb/s prototype in which three OSNs are connected by one 10-km and two 5-dm single-mode fibers in a ring configuration. Very compact and inexpensive equipment is realized by using high-speed ICs. Experimental results show the proposed architecture to be a powerful one for the realization of synchronous broadband subscriber loop systems     

Analysis of effective power budget in optical bus and star networksusing erbium-doped fiber amplifiers

The use of erbium-doped fiber optical amplifiers (EDFAs) in bus and star networks is studied. The number of stations that can be supported with and without amplifiers in a single folded bus, a double bus, and a star is determined. For a typical case, when only one station on the bus is allowed to transmit at a time, as is the case in a time-division multiplexed network, the number of stations that can be supported with amplifiers is on the order of several thousands. This number drops to less than a thousand when all stations are allowed to transmit simultaneously on different channels in a wavelength-division multiplexed network, because of amplifier gain saturation. In the former case, the bus has the potential to outperform the star, but in the latter case, the star topology is still better     

A wavelength encoded multichannel optical bus for local areanetworks

A scalable, high-speed, wavelength encoded multichannel optical bus (WEMCOB) employing the wavelength division multiplexing (WDM) technology is proposed to reduce the link speed requirement, the wiring complexity, and the number of optical amplifiers for local area networks. In this paper, a hierarchical network topology is adopted, in which a dual unidirectional WEMCOB with separate control and data channels composes the backbone network, and unidirectional tree-based WEMCOB's with centralized arbiters constitute the subnetworks. We perform a feasibility study on the implementation of a local area network based on the WEMCOB, discuss the related issues, and show that a total transmission capacity of several tens of gigabits per second (Gb/s) can be achieved to serve a large number of broadband users by utilizing today's optoelectronic technology     

A spanning bus connected hypercube: a new scalable opticalinterconnection network for multiprocessors and massively parallelsystems

A new scalable interconnection topology suitable for massively parallel systems called the spanning bus connected hypercube (SBCH) is proposed. The SBCH uses the hypercube topology as a basic building block and connects such building blocks using multidimensional spanning buses. In doing so, the SBCH combines positive features of both the hypercube (small diameter, high connectivity, symmetry, simple routing, and fault tolerance) and the spanning bus hypercube (SBH) (constant node degree, scalability, and ease of physical implementation), while at the same time circumventing their disadvantages. The SBCH topology permits the efficient support of many communication patterns found in different classes of computation such as bus-based, mesh-based, tree-based problems as well as hypercube-based problems. A very attractive feature of the SBCH network is its ability to support a large number of processors while maintaining a constant degree and constant diameter. Other positive features include symmetry, incremental scalability, and fault-tolerance. An optical implementation methodology is proposed for SBCH. The implementation methodology combines both the advantages of free space optics with those of wavelength division multiplexing techniques. A detailed analysis of the feasibility of the proposed network is also presented     

Wavelength assignment for locally twisted cube communication pattern on optical bus network-on-chip

Optical network-on-chip (NoC) is a new designing of Multi-Processor System-on-Chip (MPSoC). Global bus is the simplest logical topology of optical NoC. Static routing and wavelength assignment is one important communication mechanism of optical NoC. This paper addresses the routing and wavelength assignment (RWA) problem for locally twisted cube communication pattern on global bus optical NoC. For that purpose, a routing scheme, that is an embedding scheme, is proposed, and a wavelength assignment scheme under the embedding scheme is designed. The number of required wavelengths is shown to attain the minimum, guaranteeing the optimality of the proposed scheme.     

2.4G辅助定位在电子公交站牌中的应用分析

随着基于CDMA网络的通信终端的日益增多,电信网络往往因信息传输量大从而造成丢包率陡增,从而影响网络传输质量.特别是对通信实时性要求较高的电子公交站牌,越来越庞大的上下班客流量容易影响站牌的显示及时性.鉴于此,提高电子公交站牌的通信实时性是提高其服务质量的本质所在.针对这一目的,设计了一种基于NRF24L01的简单RF辅助传输方式,与本身的基于第三方网络的CDMA模块形成“双模”传输,从而为电子站牌提供辅助定位的功能.首先分析了电子站牌发展现状,然后对RF模块电路部分和软件实现部分进行了说明和实现,最后对2种模块进行丢包率测试.测试结果显示：该设计模式具有稳定,可靠的特点,可以为现有平台提供更精确的定位功能,为消费者提供实时的车辆到站信息.     

一种宽带光总线互连网络机群系统设计

介绍了一种宽带光总线互连网络机群系统。该系统利用宽带多层自由空间光学数据总线和VCSEL/MSMCMOS光电子集成器件实现4台计算机之间互连。专用通讯适配器实现高性能并行接口(high performance parallel interface,HIPPI)到外设部件互连(peripheral component interconnection,PCI)协议转换。该系统光互连网络传输容量可达60Gbit/s,可用于计算机之间的高速通讯。     

基于CAN总线的汽车内部网络设计

研究了CAN总线在汽车电控系统中的应用,设计了汽车内部网络拓扑结构,采用高、低速CAN总线连接实时性要求不同的ECU,通过网关完成不同速率CAN网络间的通信,并给出了网关和基本CAN节点的软、硬件实现.与传统汽车ECU间点对点的通信方式相比,采用CAN总线节省了车内布线成本、提高了ECU间信息交互的可靠性.     

机载光纤总线拓扑结构的性能研究

光纤总线因其体积小、质量轻、损耗低、容量大、抗电磁干扰能力强等优势,被广泛应用于机载系统。光纤总线网络拓扑结构类型多样,且不同拓扑下总线网络的性能表现不同,因此根据机载系统特性选取合适的光纤总线拓扑结构至关重要。面向机载光纤总线中不同组网条件,针对不同拓扑、分析时延、吞吐量和可靠性等关键性能参数及其影响因素,对总线进行建模仿真,分析时延和吞吐量,并为各拓扑结构建立失效模型,分析系统可靠性。仿真与计算结果表明,总线型拓扑结构双冗余系统更适用于机载光纤总线网络。     

Distributed arbitration scheme for on-chip CDMA bus with dynamic codeword assignment

Several code-division multiple access (CDMA)-based interconnect schemes have been recently proposed as alternatives to the conventional time-division multiplexing bus in multicore systems-on-chip. CDMA systems with a dynamic assignment of spreading codewords are particularly attractive because of their potential for higher bandwidth efficiency compared with the systems in which the codewords are statically assigned to processing elements. In this paper, we propose a novel distributed arbitration scheme for dynamic CDMA-bus-based systems, which solves the complexity and scalability issues associated with commonly used centralized arbitration schemes. The proposed arbitration unit is decomposed into multiple simple arbitration elements, which are connected in a ring. The arbitration ring implements a token-passing algorithm, which both resolves destination conflicts and assigns the codewords to processing elements. Simulation results show that the throughput reduction in an optimally configured dynamic CDMA bus due to arbitration-related overheads does not exceed 5%.     

An initialisation protocol for a CDMA based communications schemefor HFC CATV networks

An initialization protocol for a CDMA based communications system for hybrid fiber coax (HFC) central antenna television (CATV) networks is described. HFC CATV networks are shared medium access networks, employing the coaxial bus principle between an optical network terminator and the subscriber. To realize access in the upstream direction, a multiple access scheme based on CDMA can be used. However, before access is granted in the upstream direction, each cable modem connected to the coaxial bus needs to undergo a startup procedure at activation of the modem to determine timing and physical layer related settings. The initialization mechanism described performs time synchronization of a modem and the determination of the power the modem should use. Next to these physical layer settings, also the identity of a modem is determined during the initialization process     

Passive optical star bus with collision detection for CSMA/CD-based local-area networks

A prototype 16-terminal passive star bus suitable for carrier sense multiple access with collision detection (CSMA/CD)-based fiber-optic local-area network is described. Operation is at 16 Mbit/s over optical path lengths of 600 m. The optical wavelength is 830 nm. A novel and simple collision detection method based on listening onto the bus is incorporated within the system. In addition, data is scrambled instead of Manchester encoded. The effect that scrambling has on the collision detection method, as well as on the detection of both the bus idle state and the beginning and end of data packets is examined in detail. The network efficiency is calculated taking into account the operation of the scrambler as well as the collision detection method.     

Applying CDMA Technique to Network-on-Chip

The issues of applying the code-division multiple access (CDMA) technique to an on-chip packet switched communication network are discussed in this paper. A packet switched network-on-chip (NoC) that applies the CDMA technique is realized in register-transfer level (RTL) using VHDL. The realized CDMA NoC supports the globally-asynchronous locally-synchronous (GALS) communication scheme by applying both synchronous and asynchronous designs. In a packet switched NoC, which applies a point-to-point connection scheme, e.g., a ring topology NoC, data transfer latency varies largely if the packets are transferred to different destinations or to the same destination through different routes in the network. The CDMA NoC can eliminate the data transfer latency variations by sharing the data communication media among multiple users concurrently. A six-node GALS CDMA on-chip network is modeled and simulated. The characteristics of the CDMA NoC are examined by comparing them with the characteristics of an on-chip bidirectional ring topology network. The simulation results reveal that the data transfer latency in the CDMA NoC is a constant value for a certain length of packet and is equivalent to the best case data transfer latency in the bidirectional ring network when data path width is set to 32 bits.     

Optical multiple-access mesh-connected bus interconnects

We consider networks for interconnecting parallel computers that are parameterized by their degree (fan-out) of the switches that are used to build the network. Electronic networks tend towards the small fan-out/large diameter end of the spectrum due to limitations on the fan-out of electronic switches. The fan-out of systems of optical switches is anticipated to be significantly higher than electronic switches. Thus it has been suggested that optics can be used to build the complete network which is the most desirable of Clos's family of networks. Even optics, however, has limits on the fan-out of switches in any given configuration. Thus in this paper, we describe an implementation of a network with a significantly smaller degree and slightly larger network diameter than the complete network. The network that we implement is called the mesh-connected bus network. We remark, however, that it is essentially an implementation of the second most desirable network in the family of networks defined by Clos, which is widely referred to as the Clos network. We implement the network using novel free-space optical interconnection techniques along with a multiple-access scheme based on wavelength-division multiplexing     

Experimental multiuser quantum key distribution network using a wavelength-addressed bus architecture

A six-user quantum key distribution network implemented on a bus topology is experimentally demonstrated. The network employs the BB84 protocol to transmit cryptographic keys encoded unto the phase states of highly attenuated laser light to distances of up to 31 km in a standard telecommunication-grade fiber. Each user on the network is assigned a unique wavelength for communication with the network server at a time. The measured quantum bit error rate and sifted key rate compare favorably with theoretical results.     

总线型FC-AE-1553网络结构及实时性分析

针对仲裁环型与交换式FC-AE-1553总线时间延迟不易确定的问题,提出了一种新的基于无源光网络的总线型FC-AE-1553结构。该结构采用下行广播、上行分时复用的传输机制,消息在总线上的传输时间延迟非常确定,方便用户根据时序严格编排总线任务,适合应用于航空航天等强实时要求的环境。     

Register insertion bus architecture for fibre optic local area networks

A protocol for fibre optic local area networks, the register insertion bus (RIB), is proposed. RIB uses a folded-bus topology with an access scheme which includes the existence of two buffers in each station to hold packets that would conflict. Simulations have shown the access scheme to efficiently utilise the network with a minimum of overhead. RIB implements a fair access scheme at normal network loads but at high loads a priority scheme is implemented. An enhancement technique is discussed that will implement a fair access scheme by altering the time between transmissions based on the measured network load.<>     

光总线在组合导航系统中的应用分析

航空电子系统和光通信发展到一定阶段,光总线将广泛应用于航空领域。在组合导航系统中,利用光总线进行通信可以极大地提高系统整体性能。本文介绍了光总线技术的发展及研究现状,重点分析了1394总线,提出了基于1394光总线的综合导航系统的网络结构及关键技术。     

Implementing bitonic sorting on optical network-on-chip with bus topology

Photonic Network Communications - Optical network-on-chip (ONoC) is a new designing of multi-processor system-on-chip. On the one hand, global bus is a simple and common logical topology for ONoC....     

A performance and implementation comparison of bidirectional anddual bus 2-D WDM multiple-plane optical interconnections with row-columnmultihop network structures

Bidirectional and dual bus wavelength division multiplexing (WDM) two-dimensional (2-D) multiple-plane optical interconnections with row-column multihop network structures using vertical-cavity surface-emitting lasers (VCSELs) and wavelength-selective detectors are analyzed and compared in terms of the expected number of hops (switching delay) and practical implementation considerations. The bidirectional WDM optical interconnection significantly reduces the necessary implementation hardware while maintaining the performance very closely compared to the dual bus architecture. Both WDM structures show significant performance improvements even when only three to five wavelengths are used. Also, the multihop efficiency is analyzed with the consideration of both electrical hops and optical hops