一种应用于时分交换IP OVER WDM网络的动态波长分配算法

提出了一种应用于时分交换IP OVER WDM网络的动态波长分配算法。该算法通过设置空闲波长信道，并将这些信道在不同时隙以跳波长方式动态分配给数据传输速率要求较高的业务，以尽量满足用户需求。讨论了该算法的原理，并对算法性能进行了分析。结果显示该算法能够有效地满足不同用户的业务需求，进一步提高信道波长利用率。     

TWDM-PON中带有业务区分的混合资源调度算法

针对时分波分复用无源光网络长距离和广覆盖特性带来往返时延增大,造成高优先级业务时延性能严重恶化的问题,提出带有业务区分的混合资源调度算法.根据网络负载实时调整光网络单元组的波长数以实现资源共享,并动态划分子周期以对不同优先级业务进行区分服务;设计混合资源调度算法,以在线方式填充波长空隙,以离线方式保障资源高效调度.仿真结果表明,所提算法能够满足不同优先级业务的时延要求,保证服务质量,并提高信道利用率.     

多用户MIMO-OFDMA系统混合业务的跨层分组调度算法

该文提出了一种针对多输入多输出-正交频分多址系统混合业务的跨层分组调度算法。该算法基于物理层的信道状况和媒体接入控制子层用户的排队时延,分别为实时业务用户和非实时业务用户的排队时延构建相应的效用函数,以保障不同业务的服务需求。仿真结果表明:该算法不但能保证实时业务的时延需要,而且能够获得很好的吞吐量,并满足公平性要求。     

基于差值分配的信道分配算法研究

资源的高效利用与服务质量保证是多频时分多址(MF-TDMA)卫星通信系统正常运行的关键技术。通过对典型的周期轮询信道分配算法进行分析,针对该算法实时业务掉线率较高的缺点,提出了差值分配算法。新算法是在周期轮询信道分配算法的基础上,结合业务带宽需求动态变化的特点,将业务带宽申请分为固定部分与差值部分并分别采取不同的分配策略。仿真结果表明,新算法可以有效地降低实时业务的掉线率。     

多波长信道的前跳虚时钟算法

对WDM光接入网媒质接入控制协议进行了研究,基于前跳虚时钟算法和波长分配提出了一种新的WDM媒质接入控制算法,并利用积压不等式从理论上详细分析了该算法的延时特性和公平性。理论分析和计算机仿真结果都表明该算法不仅具有确定的时延保证和公平性,还能够充分利用剩余波长信道,提高了网络承载业务的能力。     

IEEE 802．16中基于信道状态的改进分组调度算法

为适应IEEE802．16无线网路的特点,降低数据的分组超时率,提高数据的平滑性,在基于信道状态的分组调度算法（CSDPS算法）的基础上,提出了一种基于信道状态的改进分组调度算法。该算法把业务区分与信道状态结合起来,既考虑了不同业务的QoS需求,也考虑了无线网络的信道特点。在降低发送速率上,给出降低速率的具体计算公式。通过理论分析,用改进算法与原有CSDPS算法进行了对比。可以发现,改进算法在分组超时率和数据平滑性上都有较大改善。     

基于覆盖范围需求的LTE下行资源分配方式

为了提高TD-LTE的网络规划质量,根据LTE的技术特征,提出一种基于覆盖范围需求的下行资源分配方式。该方法通过对控制信道的相关参数选择使得控制信道的覆盖范围与相应的业务信道趋于一致,并根据控制信道的覆盖受限范围推导出不同速率业务的频域资源块数目可取范围。理论和仿真结果表明,这种新的资源分配方案可以减少不必要的干扰和功率浪费,与现有频域资源分配方法没有考虑到网络规划的因素相比,该方法配合下行不同业务的资源分配算法则更适合于TD-LTE的资源分配,极大地提升了小区边缘的覆盖质量。     

多光纤WDM网中支持QoS的波长重路由算法

在WDM网上，波长连续性限制会降低网络的信道利用率，增加光路建立请求的阻塞率。采用波长重路由技术可以减少波长连续性限制对网络性能的影响。该文采用波长图模型，对多光纤WDM网中支持QoS的波长重路由算法进行了探讨，提出一种支持QoS的波长重路由算法－－动态选择法，并采用两种网络模型，在不同负载的动态业务下对所提算法进行了仿真研究；仿真结果表明所提算法既满足了上层业务不同的QoS要求，同时又充分利用了有限的网络资源，使全网的平均阻塞率降低。     

多波束卫星通信功率带宽联合优化算法

在多波束卫星通信系统中,资源利用率受星上能量的限制,提高资源利用率非常重要。为提高星上资源优化的灵活性,在考虑自由空间损耗、天线增益、雨衰和波束间干扰的基础上,提出一种基于不同业务需求和信道条件的多波束卫星通信下行链路功率带宽联合优化算法。该联合优化算法采用二阶差分目标函数,运用拉格朗日对偶理论和次梯度法求得该联合优化问题最优解的下界。仿真结果分析表明,与单独地优化功率和带宽算法相比,该功率带宽联合优化算法可以根据不同的业务需求和信道条件更加灵活地分配系统容量,提高了资源利用率。      

一种人与人和物到物业务共存下的异构蜂窝网络柔性接入策略

针对人与人(H2H)和物到物(M2M)业务共存的异构无线网络,该文设计了一种根据业务特性的代理节点的网络选择策略,用博弈论对以保障两类业务服务质量(QoS)需求和网络负载均衡为目标的代理节点网络选择问题进行建模,并分析了该博弈模型纳什均衡(NE)的存在性和可行性;同时,提出了基于学习自动机的分布式网络-信道选择算法(DNCSALA),求得该博弈的纳什均衡。仿真结果表明,所提算法能够获得与穷举搜索算法相近的性能,可满足共存场景中不同类型业务的QoS需求并提高网络资源利用率。     

Rerouting technique with dynamic traffic in WDM optical networks

In this paper, we have proposed an efficient wavelength rerouting algorithm for dynamic provisioning of lightpath. In wavelength division multiplexed (WDM) networks rerouting of lightpath can be used to improve throughput and to reduce blocking probability. We have proposed a shortest path wavelength rerouting (SPWRR) algorithm for dynamic traffic in WDM optical networks. The results have shown that SPWRR algorithm can improve blocking performance of the network. In this paper, low complexity algorithm has been developed which is used for the calculation of blocking probability of network. The proposed algorithm has also been applied on the realistic network such as NSFnet for calculation and optimization of blocking probability of the network.     

光网络中一种快速动态负荷均衡的波长路由算法

针对波长路由网络中动态光链路建立问题,提出了一种快速动态波长路由算法(RWA)。在路由子问题上,通过动态改进最短路径算法(Dijistra算法)权值的设置,使之符合光网络中动态流量分布,并适时更新路由信息表来适时调整网络的流量分布,减轻网络负荷,实现一种负荷均衡的路径查找。在波长分配子问题上,提出一种通过动态调节变异和交叉算子的遗传算法(VMCR-GA),可以实现快速波长搜索和分配。通过在几个网络上的仿真分析,比采用普通遗传和D算法的波长路由算法性能优越,网络阻塞率可以降低10%,波长分配效率提高30%~50%,算法的收敛性也大大提高。     

Heuristic algorithm for allocation of wavelength convertible nodesand routing coordination in all-optical networks

It is true that in all-optical networks, network performance can be improved by wavelength conversion. However, the switching node with wavelength conversion capability is still costly, and the number of such nodes should he limited in the network. In this paper, a performance optimization problem is treated in all-optical networks. We propose a heuristic algorithm to minimize an overall blocking probability by properly allocating a limited number of nodes with wavelength conversion capability. The routing strategy is also considered suitable to the case where the number of wavelength convertible nodes are limited. We validate the minimization level of our heuristic algorithm through numerical examples, and show that our algorithm can properly allocate nodes with conversion and decide routes for performance optimization     

基于强化学习的光传送网路由波长优化

针对光传送网中动态业务的路由和波长问题,提出一种基于强化学习的深度路由波长分配算法DeepRWA。算法基于软件定义网络架构,通过强化学习灵活地调整控制光传送网,实现光网络路由波长分配策略优化。针对路由选择问题,结合链路上的波长使用情况,使用A3C算法选择合适的路由,使得阻塞率最小;针对波长分配问题,使用首次命中算法选择波长。考虑阻塞率、资源利用率、策略熵、价值损失、运行时间及收敛速度等多个指标,利用14节点NSFNET网络拓扑仿真实验。结果表明:当信道中包含18个波长时,与传统KSP-FF算法相比,所提出的路由波长分配算法的阻塞率降低了0.06,资源利用率提高了0.02,但运行时间有增加;在波长数超过45以后,与传统KSP-FF算法相比,所提算法保持阻塞率和资源利用率的同时,运行时间开始降低;当信道中包含波长数为58时,与传统KSP-FF算法相比,所提算法运行时间减少了0.07 ms。由此可见,提出的算法使路由选择和波长分配得到了优化。     

WDM-TDM光网络中的动态波长路由与时隙分配算法研究

在WDM光网络中,为了进一步提高波长资源的利用率,多个业务连接可以通过时分复用(TDM)技术共享一个波长的容量。在这种基于WDM-TDM技术的光网络中建立业务连接,需要解决的核心问题之一是波长路由与时隙分配(RWTA)问题。该文研究了WDM-TDM光网络中的动态RWTA问题,提出了一种基于最大使用率方法的RWTA算法(MUB)和一种改进的MUB算法(EMUB),并对它们的性能进行了计算机仿真分析。结果表明:EMUB算法的阻塞率性能优于MUB算法,能有效地优化WDM-TDM光网络的资源利用率。     

总线形与环形全光网中波长转换器的配置算法研究

波长转换技术可以消除全光网络中的波长一致性限制,降低网络阻塞率,因而在数量有限时存在合理配置、使用波长转换器的问题,本文在推导、分析网络阻塞率的基础上,提出了一种用于总线形和环形全光网的波长转换器配置算法,并对该算法进行了计算机模拟。模拟结果表明本算法的配置结果得出的网络阻塞率与最佳配置时的非常接近,而本算法的时间复杂度仅为O（4H＋2w)。     

Dynamic Multicast Session Provisioning in WDM Optical Networks with Sparse Splitting Capability

In this work, we study dynamic provisioning of multicast sessions in a wavelength-routed sparse splitting capable WDM network with an arbitrary mesh topology where the network consists of nodes with full, partial, or no wavelength conversion capabilities and a node can be a tap-and-continue (TaC) node or a splitting and delivery (SaD) node. The objectives are to minimize the network resources in terms of wavelength-links used by each session and to reduce the multicast session blocking probability. The problem is to route the multicast session from each source to the members of every multicast session, and to assign an appropriate wavelength to each link used by the session. We propose an efficient online algorithm for dynamic multicast session provisioning. To evaluate the proposed algorithm, we apply the integer linear programming (ILP) optimization tool on a per multicast session basis to solve off-line the optimal routing and wavelength assignment given a multicast session and the current network topology as well as its residual network resource information. We formulate the per session multicast routing and wavelength assignment problem as an ILP. With this ILP formulation, the multicast session blocking probability or success probability can then be estimated based on solving a series of ILPs off-line. We have evaluated the effectiveness of the proposed online algorithm via simulation in terms of session blocking probability and network resources used by a session. Simulation results indicate that our proposed computationally efficient online algorithm performs well even when a fraction of the nodes are SaD nodes.     

WDM 网络中基于优先级的多任务波长路由分配算法

提出了一种在WDM网络中基于优先级的多任务波长路由分配算法。算法设计旨在提高光网络资源的利用率、降低网络请求阻塞率。分析了任务请求的路由类型以及负载容量对请求优先级划分的影响方式,给出了网络请求优先级划分策略,结合网络的实时状态提出了一种基于优先级的多任务波长路由分配算法。仿真结果表明,该算法相比现有算法降低了网络请求阻塞率,提高了资源利用率。     

Multicast wavelength assignment with sparse wavelength converters to maximize the network capacity using ILP formulation in WDM mesh networks

In general, multicast routing and wavelength assignment (MC-RWA) can be subdivided in routing and wavelength assignment issues in wavelength-division multiplexing (WDM) mesh networks. Previous studies on WDM multicast have mainly focused on WDM multicast routing. The multicast wavelength assignment problem is studied in this paper. A unicast routing path can be established by a lightpath in an all-optical network. However, in the multicasting case, a multicast routing tree can be established by a single light-tree or several lightpaths, or a combination of several light-trees and lightpaths. We propose a wavelength assignment algorithm for finding an optimal combination of lightpaths and light-trees to construct a newly required multicast session. First of all, two cost functions are given to evaluate the establishing cost for each feasible wavelength, and then find a set of wavelengths that covers all destinations with the minimal cost using Integer Linear Programming (ILP) formulation. We focus on maximizing the total number of users served in a multicast session and the network capacity. The simulation results show that the proposed algorithm can improve system resource utilization and reduce the blocking probability compared with the First-Fit algorithm.This research was partially supported by the Grant of National Science Council, R.O.C. (NSC 94-2745-E-155-007-URD).     

Lightpath Rerouting Algorithm to enhance blocking performance in all-optical WDM network without wavelength conversion

In this paper, we have proposed an efficient wavelength rerouting algorithm for dynamic provisioning of lightpath. In wavelength-division multiplexed (WDM) networks rerouting of lightpath can be used to improve throughput and to reduce blocking probability. We have proposed a Lightpath Rerouting Algorithm (LRRA) for dynamic traffic in WDM optical networks. The results have shown that LRRA can improve blocking performance of the network. In this paper, low complexity algorithm has been developed which is used for the calculation of blocking probability of network. The proposed algorithm has also been applied on the realistic network such as NSFnet for calculation and optimization of blocking probability of the network. The results have also shown that the proposed algorithm can be implemented to huge networks for good blocking performance of the network.