This paper proposes k-regular and k-connected(k&k) structure against multifaults in ultra-high capacity optical networks.Theoretical results show that pre-configured k&k structure can reach the lower bound on ...This paper proposes k-regular and k-connected(k&k) structure against multifaults in ultra-high capacity optical networks.Theoretical results show that pre-configured k&k structure can reach the lower bound on logical redundancy.The switching time of k&k protection structure is as quickly as ringbased protection in SDH network.It is the optimal protection structure in ultra-high capacity optical networks against multi-faults.We develop the linear programming model for k&k structure and propose a construction method for k&k structure design.Simulations are conducted for spare spectrum resources effi ciency of the pre-confi gured k&k structure under multi-faults on representative COST239 and NSFnet topologies.Numerical results show that the spare spectrum resources efficiency of k&k structure can reach the lower bound on logical redundancy in static networks.And it can largely improve spare spectrum resources effi ciency compared with p-cycles based protection structure without reducing protection effi ciency under dynamic traffi cs.展开更多
By using the optic amplifier in Nonlinear Amplifying Loop Mirror (NALM), the input power required to obtain nonlinear input-output relationship reduces to a level that nonsoliton pulse can reach. We use an accurate mo...By using the optic amplifier in Nonlinear Amplifying Loop Mirror (NALM), the input power required to obtain nonlinear input-output relationship reduces to a level that nonsoliton pulse can reach. We use an accurate model to analyze the tralnsmissivity of NALM, and show that it has intensity-filtering character, and can be used to reduce ASE noise of signals amplified by cascaded optic amplifiers. We also find that the saturation of optic amplifier in the loop affects the behaviour of NALM dramatically.展开更多
The Gigabit-capable passive optical network(GPON)technology is being considered as a promising solution for the next-generation broadband access network.Since the network topology of the GPON is point-to-multipoint,a ...The Gigabit-capable passive optical network(GPON)technology is being considered as a promising solution for the next-generation broadband access network.Since the network topology of the GPON is point-to-multipoint,a media access control called dynamic bandwidth allocation(DBA)algorithm is an important factor for determining the performance of the GPON.In this paper,we propose a new DBA algorithm to effectively and fairly allocate bandwidths among end users.This DBA algorithm supports differentiated services-a crucial requirement for a converged broadband access network with heterogeneous traffic.In this article we first reviewed the signaling and configuration of the DBA,and then proposed a new DBA scheme that implemented QoS-based priority for this need to maximally satisfy the requirements of all optical network units(ONUs)and provide differentiated services.Analyses and simulation results show that the new algorithm can improve the bandwidth utilization and realize the fairness for both different ONUs and services.展开更多
基金supported by the Major State Basic Research Development Program of China(973 Program)(Nos.2010CB328202,2010CB328204,and 2012CB315604)the HiTech Research and Development Program of China(863 Program)(Nos.2012AA01Z301,and 2012AA011302)+2 种基金the National Natural Science Foundation of China(No.60702005)the Beijing Nova Program(No.2011065)the Fundamental Research Funds for the Central Universities
文摘This paper proposes k-regular and k-connected(k&k) structure against multifaults in ultra-high capacity optical networks.Theoretical results show that pre-configured k&k structure can reach the lower bound on logical redundancy.The switching time of k&k protection structure is as quickly as ringbased protection in SDH network.It is the optimal protection structure in ultra-high capacity optical networks against multi-faults.We develop the linear programming model for k&k structure and propose a construction method for k&k structure design.Simulations are conducted for spare spectrum resources effi ciency of the pre-confi gured k&k structure under multi-faults on representative COST239 and NSFnet topologies.Numerical results show that the spare spectrum resources efficiency of k&k structure can reach the lower bound on logical redundancy in static networks.And it can largely improve spare spectrum resources effi ciency compared with p-cycles based protection structure without reducing protection effi ciency under dynamic traffi cs.
文摘By using the optic amplifier in Nonlinear Amplifying Loop Mirror (NALM), the input power required to obtain nonlinear input-output relationship reduces to a level that nonsoliton pulse can reach. We use an accurate model to analyze the tralnsmissivity of NALM, and show that it has intensity-filtering character, and can be used to reduce ASE noise of signals amplified by cascaded optic amplifiers. We also find that the saturation of optic amplifier in the loop affects the behaviour of NALM dramatically.
文摘The Gigabit-capable passive optical network(GPON)technology is being considered as a promising solution for the next-generation broadband access network.Since the network topology of the GPON is point-to-multipoint,a media access control called dynamic bandwidth allocation(DBA)algorithm is an important factor for determining the performance of the GPON.In this paper,we propose a new DBA algorithm to effectively and fairly allocate bandwidths among end users.This DBA algorithm supports differentiated services-a crucial requirement for a converged broadband access network with heterogeneous traffic.In this article we first reviewed the signaling and configuration of the DBA,and then proposed a new DBA scheme that implemented QoS-based priority for this need to maximally satisfy the requirements of all optical network units(ONUs)and provide differentiated services.Analyses and simulation results show that the new algorithm can improve the bandwidth utilization and realize the fairness for both different ONUs and services.
