The Ethemet passive optical network （EPON） is the next generation of broad-band network technique. A crucial issue in EPONs is the sharing of uplink bandwidth among optical network units （ONUs）. This article provi...The Ethemet passive optical network （EPON） is the next generation of broad-band network technique. A crucial issue in EPONs is the sharing of uplink bandwidth among optical network units （ONUs）. This article provides a novel dynamic bandwidth allocation algorithm, i.e. threshold dynamic bandwidth allocation （TDBA）, which is based on adaptive threshold, to increase resource utilization. The algorithm uses ONU data-transmitting rate to adjust optical line terminal （OLT） receiving data threshold from an ONU. Simulation results show that this algorithm can decrease average packet delay and increase network throughput in a l 0G EPON system.展开更多
A passive optical network （PON） scheme based on optical code division multiplexing （OCDM） for the downstream traffics is proposed and analyzed in detail. In the PON, the downstream traffics are broadcasted by OCDM...A passive optical network （PON） scheme based on optical code division multiplexing （OCDM） for the downstream traffics is proposed and analyzed in detail. In the PON, the downstream traffics are broadcasted by OCDM technology to guarantee the security, while the upstream traffics pass through the same optical fiber by the common time division multiple access （TDMA） technology to decrease the cost. This schemes are denoted as OCDM/TDMA-PON, which can be applied to an optical access network （OAN） with full services on demand, such as Internet protocol, video on demand, tele-presence and high quality audio. The proposed OCDM/TDMA-PON scheme combines advantages of PON, TDMA, and OCDM technology. Simulation results indicate that the designed scheme improves the OAN performance, and enhances flexibility and scalability of the system.展开更多
An optical network is a type of data communication network built with optical fibre technology. It utilizes optical fibre cables as the primary communication medium for converting data and passing data as light pulses...An optical network is a type of data communication network built with optical fibre technology. It utilizes optical fibre cables as the primary communication medium for converting data and passing data as light pulses between sender and receiver nodes. The major issue in optical networking is disjoints that occur in the network. A polynomial time algorithm Wavelength Division Multiplexing-Passive Optical Networking (WDM-PON) computes disjoints of an optical network and reduces the count of disjoints that occur in the network by separating Optical Network Units (ONU) into several virtual point-to-point connections. The Arrayed Waveguide Grating (AWG) filter is included in WDM-PON to avoid the traffic in the network thereby increasing the bandwidth capacity. In case of a failure or disjoint Ant Colony Optimization (ACO) algorithm is used to find the optimized shortest path for re-routing. For enhanced security, modified Rivert Shamir Adleman (RSA) algorithm encrypts the message during communication between the nodes. The efficiency is found to be improved in terms of delay in packet delivery, longer optical reach, optimized shortest path, packet error rate.展开更多
在Turbo EPON的ONU端,其下行数据流传输高达2.5 Gb/s。本文介绍了Turbo EPON ONU MAC控制器的逻辑框图和CRC32的校验原理,采用CRC32的硬件并行方案来实现ONU中高速数据传输的校验,然后用Modelsim进行了仿真。仿真结果证明了该设计方案...在Turbo EPON的ONU端,其下行数据流传输高达2.5 Gb/s。本文介绍了Turbo EPON ONU MAC控制器的逻辑框图和CRC32的校验原理,采用CRC32的硬件并行方案来实现ONU中高速数据传输的校验,然后用Modelsim进行了仿真。仿真结果证明了该设计方案的可实现性,实现数据的无差错高速传输。该设计方案的逻辑工作速率可以达到2 G,与常用的串行CRC32校验相比,在增加面积很有限的基础上,提高了校验速度。同时,也为下一步Turbo EPON ONU MAC控制芯片的设计研究作了一定的准备。展开更多
The motivation behind this work is the need for performance analysis of Al-Gehad/Baghdad“Fiber To The Home”(FTTH) network which is one of the Iraq Telecommunication Post and Company(ITPC) FTTH projectsin2010 in Bagh...The motivation behind this work is the need for performance analysis of Al-Gehad/Baghdad“Fiber To The Home”(FTTH) network which is one of the Iraq Telecommunication Post and Company(ITPC) FTTH projectsin2010 in Baghdad City. Based on the detailed study of this project, the design, implementation, and analysis of this network has been putting under consideration through a mathematical model simulated and performance evaluated. The link utilization and number of OLT ports (PON) had been studied and evaluated as a function of cycle time. Cost optimization was done through evaluation the total cost of PON system and who it affected with the number of ONUs (i.e. splitting ratio), as well as cost ratio between EPON and GPON is evaluated. Then GPON system has been optimized to analyze and evaluate the feeder network cost, distribution network cost, and total network cost.展开更多
文摘The Ethemet passive optical network （EPON） is the next generation of broad-band network technique. A crucial issue in EPONs is the sharing of uplink bandwidth among optical network units （ONUs）. This article provides a novel dynamic bandwidth allocation algorithm, i.e. threshold dynamic bandwidth allocation （TDBA）, which is based on adaptive threshold, to increase resource utilization. The algorithm uses ONU data-transmitting rate to adjust optical line terminal （OLT） receiving data threshold from an ONU. Simulation results show that this algorithm can decrease average packet delay and increase network throughput in a l 0G EPON system.
文摘A passive optical network （PON） scheme based on optical code division multiplexing （OCDM） for the downstream traffics is proposed and analyzed in detail. In the PON, the downstream traffics are broadcasted by OCDM technology to guarantee the security, while the upstream traffics pass through the same optical fiber by the common time division multiple access （TDMA） technology to decrease the cost. This schemes are denoted as OCDM/TDMA-PON, which can be applied to an optical access network （OAN） with full services on demand, such as Internet protocol, video on demand, tele-presence and high quality audio. The proposed OCDM/TDMA-PON scheme combines advantages of PON, TDMA, and OCDM technology. Simulation results indicate that the designed scheme improves the OAN performance, and enhances flexibility and scalability of the system.
文摘An optical network is a type of data communication network built with optical fibre technology. It utilizes optical fibre cables as the primary communication medium for converting data and passing data as light pulses between sender and receiver nodes. The major issue in optical networking is disjoints that occur in the network. A polynomial time algorithm Wavelength Division Multiplexing-Passive Optical Networking (WDM-PON) computes disjoints of an optical network and reduces the count of disjoints that occur in the network by separating Optical Network Units (ONU) into several virtual point-to-point connections. The Arrayed Waveguide Grating (AWG) filter is included in WDM-PON to avoid the traffic in the network thereby increasing the bandwidth capacity. In case of a failure or disjoint Ant Colony Optimization (ACO) algorithm is used to find the optimized shortest path for re-routing. For enhanced security, modified Rivert Shamir Adleman (RSA) algorithm encrypts the message during communication between the nodes. The efficiency is found to be improved in terms of delay in packet delivery, longer optical reach, optimized shortest path, packet error rate.
文摘在Turbo EPON的ONU端,其下行数据流传输高达2.5 Gb/s。本文介绍了Turbo EPON ONU MAC控制器的逻辑框图和CRC32的校验原理,采用CRC32的硬件并行方案来实现ONU中高速数据传输的校验,然后用Modelsim进行了仿真。仿真结果证明了该设计方案的可实现性,实现数据的无差错高速传输。该设计方案的逻辑工作速率可以达到2 G,与常用的串行CRC32校验相比,在增加面积很有限的基础上,提高了校验速度。同时,也为下一步Turbo EPON ONU MAC控制芯片的设计研究作了一定的准备。
文摘现有的光流估计网络为了获得更高的精度,往往使用相关性成本量和门控循环单元(gate recurrent unit,GRU)来进行迭代优化,但是这样会导致计算量大并限制了在边缘设备上的部署性能。为了实现更轻量的光流估计方法,本文提出局部约束与局部扩张模块(local constraint and local dilation module,LC-LD module),通过结合卷积和一次轴注意力来替代自注意力,以较低的计算量对每个匹配特征点周边区域内不同重要程度的关注,生成更准确的相关性成本量,进而降低迭代次数,达到更轻量化的目的。其次,提出了混洗凸优化上采样,通过将分组卷积、混洗操作与凸优化上采样相结合,在实现其参数数量降低的同时进一步提高精度。实验结果证明了该方法在保证高精度的同时,运行效率显著提升,具有较高的应用前景。
文摘The motivation behind this work is the need for performance analysis of Al-Gehad/Baghdad“Fiber To The Home”(FTTH) network which is one of the Iraq Telecommunication Post and Company(ITPC) FTTH projectsin2010 in Baghdad City. Based on the detailed study of this project, the design, implementation, and analysis of this network has been putting under consideration through a mathematical model simulated and performance evaluated. The link utilization and number of OLT ports (PON) had been studied and evaluated as a function of cycle time. Cost optimization was done through evaluation the total cost of PON system and who it affected with the number of ONUs (i.e. splitting ratio), as well as cost ratio between EPON and GPON is evaluated. Then GPON system has been optimized to analyze and evaluate the feeder network cost, distribution network cost, and total network cost.
