Time-slotted optical burst switched network is a potential technique to support IP over Wavelength Division Multiplexing (WDM) by introduce Time Division Multiplexing (TDM) channel to Optical Burst Switching (OBS) tec...Time-slotted optical burst switched network is a potential technique to support IP over Wavelength Division Multiplexing (WDM) by introduce Time Division Multiplexing (TDM) channel to Optical Burst Switching (OBS) technology. This paper presents a framework to evaluate blocking performance of time-slot-ted OBS networks with multi-fiber wavelength channels. The proposed model is efficient for not only single class traffic such as individual circuit switch traffics or best-effort traffics but also mixed multi-class traffics. The effectiveness of the proposed model is validated by simulation results. The study shows that blocking per-formance of multi-fiber TS-OBS network is acceptable for future Internet services.展开更多
Integrating IP and WDM is an attractive direction for research. Many solutions have been presented but it is noted that the existing switching technologies still need more concern. Since optical packet switching is no...Integrating IP and WDM is an attractive direction for research. Many solutions have been presented but it is noted that the existing switching technologies still need more concern. Since optical packet switching is not practical yet, there are just two possible solutions left. One is wavelength routing(WR), which is circuit switching in essence and the other is newly proposed optical burst switching (OBS). In this paper, characteristics of WR and OBS are first described, then, compared in several aspects. It is notice that in many aspects, the wavelength routing and burst switching are complement. This stimulates us to propose a new switching architecture, which may be considered as "mixture" of WR and OBS. We beleve the network built on new switching structure can accommodate the requirements of practicability, flexibility, robustness, effciency and etc. simultaneously. However, many related problems still need to be further researched.展开更多
In this paper we analyzed the bit error rate performance of a switching algorithm between spatial multiplex-ing and diversity for an OFDM MIMO system with ideal channel state information. The effect of channel estimat...In this paper we analyzed the bit error rate performance of a switching algorithm between spatial multiplex-ing and diversity for an OFDM MIMO system with ideal channel state information. The effect of channel estimation error was studied and we verified by simulations that the spatial multiplexing outperforms the switching algorithm. Given that the switching algorithm is based on the comparison of the channel matrix Demmel condition number to a threshold, its accuracy is compromised when channel estimation error in-creases. As a first intuitive solution, we proceeded to the adaptation of the threshold, but this didn’t lead to a pertinent improvement for the main reason that channel estimation errors did affect the MIMO techniques which use different constellation. Based on that, we proposed a new estimation technique that improved the bit error rate performance significantly.展开更多
In this paper, we propose a hybrid network architecture, called Content-based Switching Network (CSN), and its signaling scheme, which addresses the issues inherent to conventional hybrid networks which implement a ho...In this paper, we propose a hybrid network architecture, called Content-based Switching Network (CSN), and its signaling scheme, which addresses the issues inherent to conventional hybrid networks which implement a horizontal separation over the entire network (from edge to edge). We will show how CSN nodes can flexibly choose their switching paradigm (store-and-forward, optical bypass, electrical bypass) during a path establishment. Contents being transferred in one piece from end-to-end, the concept of packet can be eluded in our network, and, in particular, the user is able to avoid complicated transport layer functions, like TCP, if they are not essential. In CSN, very large contents have a special status, since they cannot be store-and-forwarded. We will show how the resource management has been designed in order to deal with such contents. A section is dedicated to deployment and feasibility issues. Simulation results will show that CSN can successfully transfer contents at 1 Gbps and 10 Gbps, the maximum speed being limited by the state-of-the-art device technologies when buffering is required (memory speed), while no major limit is observed in the case of all-optical transfers other than the optical fiber speed. Other results concern the deployment of CSN from an unclean slate approach. They will show how beneficial can be the deployment of CSN from an Optical Circuit Switching network.展开更多
针对高速旋转设备分布式测量需求,设计了一种单通道光纤旋转连接器(FROJ),并进行了性能测试。以此单通道FROJ为基础,采用磁光开关通过时分复用方式设计了四通道FROJ,在静态和动态条件下分别测试了其插入损耗。实验结果表明:该四通道FRO...针对高速旋转设备分布式测量需求,设计了一种单通道光纤旋转连接器(FROJ),并进行了性能测试。以此单通道FROJ为基础,采用磁光开关通过时分复用方式设计了四通道FROJ,在静态和动态条件下分别测试了其插入损耗。实验结果表明:该四通道FROJ的插入损耗小于4.5 d B,旋转变化量小于2 d B,在转速不超过600 r/min时可以实现光信号的可靠传输。展开更多
This paper introduces architectures of two types optical packet switched metropolitan area networks and their media access control protocols. We have designed related network simulation systems. With these simulation...This paper introduces architectures of two types optical packet switched metropolitan area networks and their media access control protocols. We have designed related network simulation systems. With these simulation systems, the characteristics and performance of the two MANs can be achieved.展开更多
Based on a media access and control（MAC）protocol,an arrangement of channels and transceivers in optical packet switching dense wavelength division multiplexing（DWDM）networks is proposed in this paper.In order to r...Based on a media access and control（MAC）protocol,an arrangement of channels and transceivers in optical packet switching dense wavelength division multiplexing（DWDM）networks is proposed in this paper.In order to reduce the cost of nodes,fixed transmitters and receivers are used instead of tunable transmitters and receivers.Two fixed transmitters and many fixed receivers are used in each node in the scheme.The average waiting delay of this scheme is analyzed through mathematics and computer simulation.The result shows that the property of the scheme is almost the same as using tunable transmitter and receiver.Furthermore,if the tuning time of tunable transmitters is taken into account,the performance of the tunable transmitter scheme is poor than this scheme at the average waiting delay and throughput of the network.展开更多
Optical Packet Switching (OPS) and transmission networks based on Wavelength Division Multiplexing (WDM) have been increasingly deployed in the Internet infrastructure over the last decade in order to meet the huge in...Optical Packet Switching (OPS) and transmission networks based on Wavelength Division Multiplexing (WDM) have been increasingly deployed in the Internet infrastructure over the last decade in order to meet the huge increasing demand for bandwidth. Several different technologies have been developed for optical packet switching such as space switches, broadcast-and-select, input buffered switches and output buffered switches. These architectures vary based on several parameters such as the way of optical buffering, the placement of optical buffers, the way of solving the external blocking inherited from switching technologies in general and the components used to implement the WDM. This study surveys most of the exiting optical packet switching architectures. A simulation-based comparison of input buffered and output buffered architectures is presented. The performance analysis of the selected two architectures is derived using simulation program and compared at different scenarios. We found that the output buffered architectures give better performance than input buffered architectures. The simulation results show that the-broadcast-and-select architecture is attractive in terms that it has lees number of components compared to other switches.展开更多
随着经济的持续发展,通信工程领域取得巨大突破,各地区用户对信息传输的质量、效率提出更高的要求,传输技术的推广与应用也受到广泛关注。现阶段,通信工程中所应用的传输技术类型主要有同步数字体系(Synchronous Digital Hierarchy,SDH...随着经济的持续发展,通信工程领域取得巨大突破,各地区用户对信息传输的质量、效率提出更高的要求,传输技术的推广与应用也受到广泛关注。现阶段,通信工程中所应用的传输技术类型主要有同步数字体系(Synchronous Digital Hierarchy,SDH)、波分复用(Wavelength Division Multiplexing,WDM)以及自动交换光网络(Automatic Switched Optical Network,ASON)3种。传输技术在通信工程中的有效应用可以极大地提升信号传输的安全性和可靠性,从而发挥出自身的价值。针对传输技术在通信工程中的应用展开深入探讨,介绍了传输技术的类型、特点及具体应用,以供参考。展开更多
基金Founded by the National Natural Science Foundation of China (No.60502005).
文摘Time-slotted optical burst switched network is a potential technique to support IP over Wavelength Division Multiplexing (WDM) by introduce Time Division Multiplexing (TDM) channel to Optical Burst Switching (OBS) technology. This paper presents a framework to evaluate blocking performance of time-slot-ted OBS networks with multi-fiber wavelength channels. The proposed model is efficient for not only single class traffic such as individual circuit switch traffics or best-effort traffics but also mixed multi-class traffics. The effectiveness of the proposed model is validated by simulation results. The study shows that blocking per-formance of multi-fiber TS-OBS network is acceptable for future Internet services.
文摘Integrating IP and WDM is an attractive direction for research. Many solutions have been presented but it is noted that the existing switching technologies still need more concern. Since optical packet switching is not practical yet, there are just two possible solutions left. One is wavelength routing(WR), which is circuit switching in essence and the other is newly proposed optical burst switching (OBS). In this paper, characteristics of WR and OBS are first described, then, compared in several aspects. It is notice that in many aspects, the wavelength routing and burst switching are complement. This stimulates us to propose a new switching architecture, which may be considered as "mixture" of WR and OBS. We beleve the network built on new switching structure can accommodate the requirements of practicability, flexibility, robustness, effciency and etc. simultaneously. However, many related problems still need to be further researched.
文摘In this paper we analyzed the bit error rate performance of a switching algorithm between spatial multiplex-ing and diversity for an OFDM MIMO system with ideal channel state information. The effect of channel estimation error was studied and we verified by simulations that the spatial multiplexing outperforms the switching algorithm. Given that the switching algorithm is based on the comparison of the channel matrix Demmel condition number to a threshold, its accuracy is compromised when channel estimation error in-creases. As a first intuitive solution, we proceeded to the adaptation of the threshold, but this didn’t lead to a pertinent improvement for the main reason that channel estimation errors did affect the MIMO techniques which use different constellation. Based on that, we proposed a new estimation technique that improved the bit error rate performance significantly.
文摘In this paper, we propose a hybrid network architecture, called Content-based Switching Network (CSN), and its signaling scheme, which addresses the issues inherent to conventional hybrid networks which implement a horizontal separation over the entire network (from edge to edge). We will show how CSN nodes can flexibly choose their switching paradigm (store-and-forward, optical bypass, electrical bypass) during a path establishment. Contents being transferred in one piece from end-to-end, the concept of packet can be eluded in our network, and, in particular, the user is able to avoid complicated transport layer functions, like TCP, if they are not essential. In CSN, very large contents have a special status, since they cannot be store-and-forwarded. We will show how the resource management has been designed in order to deal with such contents. A section is dedicated to deployment and feasibility issues. Simulation results will show that CSN can successfully transfer contents at 1 Gbps and 10 Gbps, the maximum speed being limited by the state-of-the-art device technologies when buffering is required (memory speed), while no major limit is observed in the case of all-optical transfers other than the optical fiber speed. Other results concern the deployment of CSN from an unclean slate approach. They will show how beneficial can be the deployment of CSN from an Optical Circuit Switching network.
文摘针对高速旋转设备分布式测量需求,设计了一种单通道光纤旋转连接器(FROJ),并进行了性能测试。以此单通道FROJ为基础,采用磁光开关通过时分复用方式设计了四通道FROJ,在静态和动态条件下分别测试了其插入损耗。实验结果表明:该四通道FROJ的插入损耗小于4.5 d B,旋转变化量小于2 d B,在转速不超过600 r/min时可以实现光信号的可靠传输。
文摘This paper introduces architectures of two types optical packet switched metropolitan area networks and their media access control protocols. We have designed related network simulation systems. With these simulation systems, the characteristics and performance of the two MANs can be achieved.
文摘Based on a media access and control（MAC）protocol,an arrangement of channels and transceivers in optical packet switching dense wavelength division multiplexing（DWDM）networks is proposed in this paper.In order to reduce the cost of nodes,fixed transmitters and receivers are used instead of tunable transmitters and receivers.Two fixed transmitters and many fixed receivers are used in each node in the scheme.The average waiting delay of this scheme is analyzed through mathematics and computer simulation.The result shows that the property of the scheme is almost the same as using tunable transmitter and receiver.Furthermore,if the tuning time of tunable transmitters is taken into account,the performance of the tunable transmitter scheme is poor than this scheme at the average waiting delay and throughput of the network.
文摘Optical Packet Switching (OPS) and transmission networks based on Wavelength Division Multiplexing (WDM) have been increasingly deployed in the Internet infrastructure over the last decade in order to meet the huge increasing demand for bandwidth. Several different technologies have been developed for optical packet switching such as space switches, broadcast-and-select, input buffered switches and output buffered switches. These architectures vary based on several parameters such as the way of optical buffering, the placement of optical buffers, the way of solving the external blocking inherited from switching technologies in general and the components used to implement the WDM. This study surveys most of the exiting optical packet switching architectures. A simulation-based comparison of input buffered and output buffered architectures is presented. The performance analysis of the selected two architectures is derived using simulation program and compared at different scenarios. We found that the output buffered architectures give better performance than input buffered architectures. The simulation results show that the-broadcast-and-select architecture is attractive in terms that it has lees number of components compared to other switches.
