E-OBS网络中一种基于窗口的资源预留机制

为了有效地降低突发包的阻塞率和保证网络的服务质量,提出了模拟光突发交换（E-OBS）网络中一种偏置时间连续可变的基于窗口资源预留机制。在E-OBS核心路由器的控制信道（CC）上设置资源预留窗口,以此决定是否允许控制包为相应的突发包预留链路资源,并且给出了该机制下关于阻塞概率的近似方程式。仿真结果表明,适当增加资源预留窗...     

基于滑动窗口的LRU大流检测算法

由于高速链路中的流量测量缺乏可扩展性且高速链路中及时准确的识别大流对网络测量、控制和管理有重要的意义,且在高速链路中能有效、合理的利用有限的资源,是解决资源紧缺的有效方法,基于此提出一种基于滑动窗口的资源可控的LRU淘汰机制大流量测量算法。通过"滑动窗口"机制,实现流大小的无偏估计,然后采用LRU的思想过滤小流、检测大流。仿真实验证明该算法的可行性。     

基于滑动窗口技术的有限域GF(2n)乘法算法

在分析现有有限域GF(2n)乘法算法的基础上,将滑动窗口技术应用到有限域GF(2n)的乘法运算中,提出了一个基于滑动窗口技术的有限域GF(2n)乘法算法,分析和仿真结果表明,与被认为目前最快的有限域GF(2n)乘法算法一固定窗口算法相比,该算法有更好的实现效率.     

基于FMIPv6的资源预留协议扩展研究

提出一种在无线移动环境下保障用户通信服务质量的资源预留扩展方案。该方案有效地利用了FMIPv6（Fast Handovers for Mobile IPv6）的工作过程,通过扩展FBU（Fast Binding Update）和HI（Handoff Initiate）消息,使其能够携带QoS（Quality of Service）对象,从而将移动管理和资源预留两个过程合并为一个过程。该方案引入了提前预留与公共路径利用等一系列新机制。分析结果表明,在无线移动环境下该方案能够有效地降低预留重建延迟,提高了链路资源的使用效率。     

基于无锁可复用滑动窗口的流量控制方法

滑动窗口是一种重要的流量控制技术。针对传统滑动窗口机制存在滑动过程中需要移动过多数据,从而导致传输效率不高,以及控制状态变化时采用同步锁机制而带来的性能问题,提出一种可无锁状态变化控制的可复用滑动窗口技术。该技术在窗口滑动过程中不移动数据,而是采用重写的方式来进行数据更新,并且它采用无锁算法更新窗口中的状态变化。通过理论分析和在实际应用中表明,该技术能够高效地应用于实际的数据传输流量控制中。     

基于模式间串扰避免的弹性光交换节点冲突解决方法

为了减少业务在少模光纤空分复用弹性光网络全光交换节点内资源冲突的概率,该文在全光分层节点结构中配置共享的有限频谱转换器与资源预留模块(LARSL),提出基于模式间串扰避免的空-频-时域联合资源冲突解决算法(LARSL-CACRA)。在空-频域,为LARSL-CACRA设计基于模式间串扰避免的滑动窗的模式-频谱资源块计算方法,使频谱冲突业务获得负载更均衡的模式-频谱资源块。对于仍然冲突的业务,LARSL-CACRA使用时域资源预留模块,进一步降低业务带宽阻塞率。仿真结果表明,该文设计的LARSL-CACRA可以改善交换节点带宽阻塞率,并减少业务平均时延。     

高速广域网的流量和拥塞控制

为了防止网络性能下降和可能的瘫痪，必须控制高速广域网（ＨＳ－ＷＡＮ）的拥塞。本文用泄漏窗口的机理（ＬＷ）控制拥塞。ＬＷ是滑动窗口的修正，允许用户发送的业务量超过网络负载确定的窗口。用加标记的信元区分超量业务，在拥塞节点放弃有标记的信元。通过仿真证明ＬＷ的平均端到端时延和信元丢失概率小于滑动窗口。与虚拟漏斗（ＶＬＢ）比较，在负载增加到大于０．７，接近拥塞时，ＬＷ的性能比ＶＬＢ优越。     

基于模式间串扰避免的弹性光交换节点冲突解决方法

为了减少业务在少模光纤空分复用弹性光网络全光交换节点内资源冲突的概率,该文在全光分层节点结构中配置共享的有限频谱转换器与资源预留模块(LARSL),提出基于模式间串扰避免的空-频-时域联合资源冲突解决算法(LARSL-CACRA).在空-频域,为LARSL-CACRA设计基于模式间串扰避免的滑动窗的模式-频谱资源块计算方法,使频谱冲突业务获得负载更均衡的模式-频谱资源块.对于仍然冲突的业务,LARSL-CACRA使用时域资源预留模块,进一步降低业务带宽阻塞率.仿真结果表明,该文设计的LARSL-CACRA可以改善交换节点带宽阻塞率,并减少业务平均时延.     

基于滑动窗口抗差自适应滤波的SINS/DVL组合导航算法

捷联惯性导航系统（SINS）/多普勒测速仪（DVL）组合导航时，需要考虑多普勒速度信息中出现的野值和噪声特性变化对导航精度的影响。针对上述问题，提出基于滑动窗口抗差自适应滤波的SINS/DVL 组合导航算法。首先建立状态变换漂移误差角系统误差模型，在速度误差方程中用重力常值项代替比力项，减少比力项引起的速度误差，提高模型的准确性。然后利用新息序列判别野值，若异常则采用滑动窗口数据修正错误新息，并使用带遗忘因子的自适应滤波在线估计量测噪声。实验结果证明，新的系统误差模型和滑动窗口抗差自适应滤波能有效减缓位置误差的累积。2 h 的SINS/DVL 组合导航中误差航程比优于1.05%，相比于传统卡尔曼滤波性能提升39.66%。     

一种考虑边缘检测的自适应窗口相干斑抑制

本文针对传统SAR图像相干斑空域滤波使用固定窗口所带来的问题,提出一种采用边缘检测和自适应滑动窗口技术联合降噪的相干斑抑制算法。该算法先把初始窗口的所有像素作为样本并统计样本局域方差系数,然后与初始阈值作比较:如果小于初始阈值,则采用方形窗口自适应滑动窗口算法进行滤波,否则采用利用边缘检测确定的变形窗口自适应滑动窗口算法进行滤波。仿真图像和真实雷达图像降噪实验结果表明,该算法在边缘保持和去噪方面具有更好的滤波性能。     

Auction-Based Resource Reservation in 2.5/3G Networks

We consider UMTS networks in which users request services other than telephony that last for long time intervals: e.g., video clips that last for several minutes. The duration of network time-slots over which resource units are allocated is much shorter. This complicates consistent reservation of resources over longer time scales, where consistent reservation is required to ensure that service quality is constant throughout the entire service session. In this paper, we define an auction-based mechanism for nearly consistent reservation of the resources of a UMTS (or GPRS) network by the users that value them the most, in order to satisfy the longer time scale requirements of their service sessions. Each of these sessions has a fixed target bit-rate. The mechanism is based on a series of Generalized Vickrey Auctions and a set of predefined user utility functions that we propose. Bidding is performed automatically on behalf of the users on the basis of each user's selection of one of these utility functions and his declaration of a total willingness to pay. We argue that under our mechanism the user does not have a clear incentive of not performing a truthful selection of a bidding function according to his own utility. The utility functions we define express appropriately the preferences of the users with respect to the resource allocation pattern in the cases where perfectly consistent allocation cannot be attained. We also provide a mapping of these functions to the UMTS service classes. The effectiveness of our resource reservation mechanism is demonstrated by means of experiments. It appears that most of the users either are served very satisfactorily or essentially are not served at all. The mechanism is implemented at the network base station, and is applicable in practical cases of networks with large numbers of users whose sessions last for many slots.     

New signaling procedures in ATM networks for advance resource reservation

Currently, communication with resource reservation on ATM networks has been required by popularization of multimedia applications. Types of resource reservation are classified into two types according to reservation timing. One type invokes resource reservation just before communication between users. Another type invokes it in advance. In this type, resources can be reserved with communication time periods invoked by a user, well before actual communication. For the former type, several standardization committees, such as the ATM Forum and ITU‐T, have provided some signaling protocols. However, the latter type has no signaling protocol although necessity of this type has increased. This paper presents approaches of this type at first. Next, it proposes new signaling protocols to support this type keeping consistency with the conventional protocols for the former type, and compares proposed protocols. Moreover, it presents mechanisms to reserve resources cooperating with proposed signaling protocols. This revised version was published online in June 2006 with corrections to the Cover Date.     

Exploiting user profiles to support differentiated services in next-generation wireless networks

In the next-generation wireless network, user profiles such as the location, the velocity (both speed and direction), and the resource requirements of the mobile device can be accurately determined and maintained by the network on a per-user basis. We investigate the design of a wireless network architecture that exploits user profiles to maximize network efficiency and provide better quality-of-service (QoS) to different classes of users. In this article we provide implementation guidelines of such an architecture for the third-generation partnership project (3GPP) network. The key underlying primitive of the architecture is the use of both real-time and aggregate user profiles to perform advance resource reservation in the handoff target cells of the wireless cellular network. We identify various factors that can influence the efficiency of the resource reservation scheme, and through a simulation analysis of an example scenario we show the impact of these factors on the QoS that profiled users receive. The example scenario comprises two service classes: a high cost, profiled service with higher QoS; and a lower cost, non-profiled service with best-effort QoS. The results show that high QoS can be guaranteed to users who subscribe to the profiled service.     

移动Internet的QoS保证

本文分别从分组级QoS和连接级QoS两个层面,重点阐述了支持移动用户QoS性能的关键技术,讨论了路由技术、资源预留和准入控制技术与网络QoS的关系,并且从不同的技术角度,探讨了在无线／移动网络中提供各种QoS的机制与策略。     

基于多门限预留机制的自适应带宽分配算法

针对异构无线网络融合环境提出了一种基于多门限预留机制的自适应带宽分配算法,从而为多业务提供QoS保证。该算法采用多宿主传输机制,通过预设各个网络中不同业务的带宽分配门限,并基于各个网络中不同业务和用户的带宽分配矩阵,根据业务k支持的传输速率等级需求和网络状态的变化,将自适应带宽分配问题转化为一个动态优化问题并采用迭代方法来求解,在得到各个网络中不同业务和用户优化的带宽分配矩阵的同时,在带宽预留门限和网络容量的约束条件下实现网络实时吞吐量的最大化,以提高整个异构网络带宽的利用效率。数值仿真结果显示,所提算法能够支持满足QoS需求的传输速率等级,减小了新用户接入异构网络的阻塞概率,提高了平均用户接入率并将网络吞吐量最大提高40%。     

An Adaptive Multicast Tree with QoS Support for Heterogeneous Recipients

This paper proposes a new protocol called MQ, Multicast with QoS, which supports multimedia group communications with QoS guarantees for heterogeneous recipients. With MQ, while resource reservation is de-coupled from QoS multicast routing, they are integrated in a way to avoid the problem of sender-oriented path determination, a problem that occurs when RSVP is used in conjunction with QoS routing for heterogeneous reservations. Being a truly receiver-oriented and integrated scheme for multimedia multicasting, MQ supports such integration in a robust, scalable and loop-free way, accommodates heterogeneous users with varied QoS, dynamically adjusts QoS trees to improve resource utilization, and benefits from being an integrated mechanism to ensure end-to-end QoS services. We have also conducted simulations to evaluate the performance of MQ. MQ demonstrates its advantages to conventional loosely coupled integration of IP multicasting, resource reservation and QoS routing, in terms of better accommodation of heterogeneous users, higher scalability, lower blocking probability for users to join groups with service guarantee, and more efficient resource utilization to enhance system performance.     

高速客运通信系统中的动态资源预留

针对高速客运系统中用户频繁切换产生的大量资源开销,引入了组移动性概念,通过设置列车中继站,实现了车内用户的单用户切换方式.同时,针对大量用户同时切换至目标基站导致的基站拥塞,提出了基于基站协作的动态资源预留方案.即当前基站根据列车运行状态信息提前获知切换目标基站,并通告其资源需求,使其为车内用户预留资源.仿真结果表明列车业务量对系统性能产生了严重影响,采用动态资源预留方案,可以有效地提高列车用户的通信性能.     

基于SDN框架的网络资源定价策略

针对网络中用户集中提出资源请求所造成资源负载过重和网络拥塞的问题,提出一种基于SDN架构的网络资源定价策略。首先,分析用户的需求和消费模式,确定资源交易模型。其次,结合现货消费模式和计划消费确定预约机制下资源动态定价策略模型。最后,根据所提出的资源定价策略,对资源价格进行实例仿真,结果表明,通过价格刺激用户提前预约资源,结合每个用户的信任度与消费习惯给出相应的优惠价格,可以有效地避免用户集中获取网络资源。