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
Passive optical networks (PONs) offer suffi-cient bandwidth to transfer huge amount having different packet sizes and data rates being generated by fusion of various networks. Additionally, multiple optical line termi...Passive optical networks (PONs) offer suffi-cient bandwidth to transfer huge amount having different packet sizes and data rates being generated by fusion of various networks. Additionally, multiple optical line terminals (OLTs) PONs reduce the computational com-plexity of data processing for nonuniform traffic. However, in order to improve the bandwidth allocation efficiency of a mixture of service providers, dynamic bandwidth algo-rithm (DBA) is needed for uplink communication. In this paper, a PON based open access network (OAN) is analyzed for bi-directional communication at various data rates. Multiple wavelengths are used to modulate the data of various service providers to evade the complicated DBA for uplink data broadcasting. The performance of the network is reported in terms of bandwidth exploitation, uplink effectiveness, overhead-to-data ratio and time cycle duration. The network is analyzed at various data rates to reveal the data accommodation capacity.展开更多
随着千兆光网的全面建成,光接入网设备已经成为电信耗能需要重点关注的部分。为此,广东电信利用大数据对光线路终端(Optical Line Terminal,OLT)设备配置、端口状态变化、端口放号、性能流量等进行分析,设计了OLT设备动态节能模型,实现...随着千兆光网的全面建成,光接入网设备已经成为电信耗能需要重点关注的部分。为此,广东电信利用大数据对光线路终端(Optical Line Terminal,OLT)设备配置、端口状态变化、端口放号、性能流量等进行分析,设计了OLT设备动态节能模型,实现对OLT板卡端口的动态节能管理。展开更多
为有效解决时分波分复用无源光网络(time and wavelength division multiplexed passive optical network,TWDM-PON)中因采用节能算法而导致的业务时延恶化问题,提出一种考虑业务QoS的光线路终端(optical line terminal,OLT)节能算法。...为有效解决时分波分复用无源光网络(time and wavelength division multiplexed passive optical network,TWDM-PON)中因采用节能算法而导致的业务时延恶化问题,提出一种考虑业务QoS的光线路终端(optical line terminal,OLT)节能算法。通过建立针对局端设备光线路终端的新型能耗模型,使发射机和接收机能够独立地关闭或开启,从而在上下行业务不对称的情况下能够最大化地降低光线路终端能耗;通过区分业务、调整轮询周期的大小以及工作收发机的数目,保证不同业务QoS的要求。仿真表明,算法在保证业务QoS的前提下,最大化地降低了TWDM-PON中OLT的能耗。展开更多
介绍了舟山±200 k V多端柔性直流输电工程换流站光TA(电流互感器)配置和应用情况。通过对换流站内不控充电启动试验的波形分析,找出了光TA电流异常原因,给出了整改方案。进行了一次注流试验验证并最终通过站系统的OLT试验和STATCO...介绍了舟山±200 k V多端柔性直流输电工程换流站光TA(电流互感器)配置和应用情况。通过对换流站内不控充电启动试验的波形分析,找出了光TA电流异常原因,给出了整改方案。进行了一次注流试验验证并最终通过站系统的OLT试验和STATCOM试验验证了方案的正确性。指出在柔性直流输电工程中对于光TA的测试,除了传统的精度试验外,必须增加有针对性的一次注流试验。展开更多
不同用户接入终端的出现使得光接入系统中上行链路的通信带宽需求急剧增加,低传输成本、高频带利用率的上行多进制光信号接入成为必然选择。设计了一种上行八进制相移键控信号并进行零差相干探测的新方案。该方案中,在光网络单元中级联...不同用户接入终端的出现使得光接入系统中上行链路的通信带宽需求急剧增加,低传输成本、高频带利用率的上行多进制光信号接入成为必然选择。设计了一种上行八进制相移键控信号并进行零差相干探测的新方案。该方案中,在光网络单元中级联3个相位电光调制器实现了高频带利用率八进制相移键控光信号的产生,在光线路终端中采用下行光信号载波作为混频源结合数字信号处理模块,实现了上行光信号的零差相干探测,相比较只采用相干探测技术的方案其接收机灵敏度值的提高超过了2 d B。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Passive optical networks (PONs) offer suffi-cient bandwidth to transfer huge amount having different packet sizes and data rates being generated by fusion of various networks. Additionally, multiple optical line terminals (OLTs) PONs reduce the computational com-plexity of data processing for nonuniform traffic. However, in order to improve the bandwidth allocation efficiency of a mixture of service providers, dynamic bandwidth algo-rithm (DBA) is needed for uplink communication. In this paper, a PON based open access network (OAN) is analyzed for bi-directional communication at various data rates. Multiple wavelengths are used to modulate the data of various service providers to evade the complicated DBA for uplink data broadcasting. The performance of the network is reported in terms of bandwidth exploitation, uplink effectiveness, overhead-to-data ratio and time cycle duration. The network is analyzed at various data rates to reveal the data accommodation capacity.
文摘为有效解决时分波分复用无源光网络(time and wavelength division multiplexed passive optical network,TWDM-PON)中因采用节能算法而导致的业务时延恶化问题,提出一种考虑业务QoS的光线路终端(optical line terminal,OLT)节能算法。通过建立针对局端设备光线路终端的新型能耗模型,使发射机和接收机能够独立地关闭或开启,从而在上下行业务不对称的情况下能够最大化地降低光线路终端能耗;通过区分业务、调整轮询周期的大小以及工作收发机的数目,保证不同业务QoS的要求。仿真表明,算法在保证业务QoS的前提下,最大化地降低了TWDM-PON中OLT的能耗。
文摘介绍了舟山±200 k V多端柔性直流输电工程换流站光TA(电流互感器)配置和应用情况。通过对换流站内不控充电启动试验的波形分析,找出了光TA电流异常原因,给出了整改方案。进行了一次注流试验验证并最终通过站系统的OLT试验和STATCOM试验验证了方案的正确性。指出在柔性直流输电工程中对于光TA的测试,除了传统的精度试验外,必须增加有针对性的一次注流试验。
文摘不同用户接入终端的出现使得光接入系统中上行链路的通信带宽需求急剧增加,低传输成本、高频带利用率的上行多进制光信号接入成为必然选择。设计了一种上行八进制相移键控信号并进行零差相干探测的新方案。该方案中,在光网络单元中级联3个相位电光调制器实现了高频带利用率八进制相移键控光信号的产生,在光线路终端中采用下行光信号载波作为混频源结合数字信号处理模块,实现了上行光信号的零差相干探测,相比较只采用相干探测技术的方案其接收机灵敏度值的提高超过了2 d B。
