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1.
Algorithm for Delay-Constrained Minimal Cost Group Multicasting 总被引：1，自引：0，他引：1
Group multicast routing algorithms satisfying quality of service requirements of real-time applications are essential for high-speed networks. A heuristic algorithm was presented for group multicast routing with bandwidth and delay constrained. A new metric was designed as a function of available bandwidth and delay of link, And source-specific routing trees for each member were generated in the algorithm by using the metric, which satisfy member＇s bandwidth and end-to-end delay requirements. Simulations over random network were carried out to compare the performance of the proposed algorithm with that from literature. Experimental results show that the algorithm performs better in terms of network cost and ability in constructing feasible multicast trees for group members. Moreover,the algorithm can avoid link blocking and enhance the network behavior efficiently. 相似文献
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Multicasting is a communication service that allows an application to efficiently transmit copies of data packets to a set of destination nodes. The problem of finding a minimum cost multicast tree can be formulated as a minimum Steiner tree problem in networks, which is NP-completeness. MPH (minimum path cost heuristic) algorithm is a famous solution to this problem. In this paper,we present a novel solution TPMPH (two phase minimum path cost heuristic) to improve the MPH by generating the nodes and the edges of multicast tree separately. The cost of multicast tree generated by the proposed algorithm with the same time as MPH is no more than that of MPH in the worst case. Extensive simulation results show that TPMPH can effectively improve the performance on MPH, and performs better in large-scale networks and wireless networks. 相似文献
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李婧晖 《四川教育学院学报》2010,26(3):114-116
设计一个新的建树算法,该算法适用于应用层多播。考虑到应用层上两点间代价的不对称性和实时性要求,设计出一种基于源端的多播树建立方法,以保证组内每个成员都能及时收到组内其它任何一个成员发送的报文。多播组的成员通过测量应用层的点到点的瓶颈带宽和往返时延获得链路代价,并分别以自己为根节点建立多播树,以便在报文转发时确定最优路径。 相似文献
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组播作为一种节约网络带宽、降低网络负载的有效手段,在视频传输中具有广阔的应用前景。本文针对组播中的会话内公平性问题,深入研究了多速率组播分层解决方案的实现机制,并基于目前的研究现状和进展指出了分层组播现存的有关问题。同时为分析分层解决方案在解决组播会话内公平性问题中的有效性,文中通过网络仿真器NS进行了实验评价。 相似文献
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波长变换技术是组成全光分组交换网中的重要技术之一,而当前比较成熟的基于半导体光放大器的波长转换技术在传输速率、信号格式、波长转换通道数和灵活性上还存在缺陷,不利于今后高速大容量光网络的发展。本文提出了基于周期极化掺氧化镁铌酸锂（PPMgLN）晶体的非线性波长转换方案,该方案采用I型准相位匹配（QPM）技术实现宽带倍频（SHG）、和频（SFG）和差频（DFG）,再通过级联二阶倍频差频（cSHG/DFG）或级联二阶和频差频（cSFG/DFG）波长转换机制,实现全光通信波长转换。在全光网络中,该方案能够很好地解决波长竞争、传输格式达到完全透明、降低网络阻塞率、提高网络传输速率等问题。 相似文献
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The Ethernet 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 10G EPON system. 相似文献
7.
Chen Jian Qian Ying Chen Huimin Li Yingchun Chen Jianqiang 《上海大学学报(英文版)》1998,2(4):328-333
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基于冲突图模型形成的二进制整数规划,提出了一种蜂窝网络中支持D2D通信的无线资源分配方法．首先,提出一种频率资源分配算法,即为每个D2D链路都分配一个频率资源块．分配频率资源时将尽可能地利用蜂窝网络中的无线频率资源空间重用机会．然后,提出一种时隙调度算法,即为所有分配同一频率资源块的D2D链路进行时隙资源调度．调度时隙资源时将保证使用同一频率资源块的D2D链路之间达到长期平均吞吐率的比例公平．通过计算机仿真对所提出方法的性能进行了验证,结果表明该方法能够在蜂窝网络中实现D2D通信功能． 相似文献
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CHAKARESKI Jacob 《浙江大学学报(A卷英文版)》2006,7(5):773-783
INTRODUCTION According to yearly statistics the demand for multimedia traffic over computer networks is con- stantly on the increase (Nielsen//NetRatings, http:// www.nielsen-netratings.com/). Therefore, it is inevi- table that situations where different media streams will need to share communication resources will be- come commonplace. In such cases, it would be of interest to optimize the overall performance of the network. In other words, resources should be allo- cated across the com… 相似文献
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LIU Yun-qiang YU Song-yu WANG Xiang-wen ZHOU Jun 《浙江大学学报(A卷英文版)》2006,7(4):543-548
INTRODUCTION Many emerging video applications, such as video-on-demand (VOD) and distance learning, rely on the efficient transfer of compressed video. For the same average bandwidth, variable bit rate (VBR) encoded video streams have higher perceivable qual- ity and greater opportunity for statistical multiplexing gains compared to constant bit rate (CBR) video streams (McManus and Ross, 1996). However, VBR video typically shows significant burstiness on mul- tiple time scales, due … 相似文献
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INTRODUCTION Most packing problems (Dowsland and Dow-sland, 1992) are NP-hard (Garey and Johnson, 1979); among which are bin-packing, floorplan, rectangle packing, packing a set of circles into a large circle or square, non-rectangular packing problems and so on (Li and Milenkovic, 1995; Liang et al., 2002; Lip-nitskii, 2002; Milenkovic and Daniels, 1996; Milenk-ovic et al., 1991; Osogami and Okano, 2003; Wang, 2002). Some of these such as bin-packing problem and rectangle packing p… 相似文献
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互联网络RCP(Ringed Crossed cube Petersen)拓扑结构被提出后并没有给出组播算法.本文利用RCP(n)网络的正则性、良好的可扩展性,以及比Qn,HP(n),RHP(n)网络直径更短和构造开销更小这些特性,按照构造组播树的方法,给出了RCP(n)网络的组播路由算法,并对该算法作了性能分析. 相似文献
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提出了一种能在承载多媒体业务的移动通信网络中提供较高服务质量保证的接入控制方法 .该方法将接入控制与带宽预留相结合 ,保证传输业务服务质量的要求 .仿真结果表明 ,与两种传统的接入控制算法相比 ,本文所提出的算法能够使强行中止概率降低 .该算法能用于未来多媒体通信系统中 相似文献
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INTRODUCTION With the emergence of wireless technology, various multimedia services, e.g., audio and/or video, are reaching us today through portable devices any- time, anywhere and even more increasingly accessi- ble in the near future. High quality video streaming over wireless IP is one of the most attractive applica- tions by ongoing deployment of wireless local area network (WLAN) hotspots and even powerful Wi- MAX mobile coverage. However, the present Internet is not providing a… 相似文献
15.
研究了多用户场景下多载波码分多址系统（MC—CDMA）的下行信道和功率分配,并将吞吐最大化问题建模成一个混合整数优化问题．为了简化分析,将问题分成2个低复杂度的子问题：功率分配和信道分配．这2个子问题可分别被一个次最优自适应功率分配算法（APA）和一个最优自适应信道分配算法（ACA）解决．通过联合APA和ACA算法,进一步提出了一个自适应信道和功率的分配方案．仿真结果表明：与传统的均匀功率分配算法相比,提出的APA算法更加适用于MC—CDMA系统;此外,提出的自适应信道和功率分配方案可以显著地提高系统吞吐量性能． 相似文献
16.
Multi-dimensional nonlinear knapsack problems are often encountered in resource allocation, industrial planning and computer networks. In this paper, a surrogate dual method was proposed for solving this class of problems. Multiply constrained problem was relaxed to a singly constrained problem by using the surrogate technique. To compute tighter bounds of the primal problem, the cutting plane method was used to solve the surrogate dual problem, where the surrogate relaxation problem was solved by the 0-1 linearization method. The domain cut technique was employed to eliminate the duality gap and thus to guarantee the convergence of tile algorithm. Numerical results were reported for large-scale multi-dimensional nonlinear knapsack problems. 相似文献
17.
把波分复用技术应用于计算机光互连网络 ,通过分析波长和网络路由之间的关系 ,提出了采用波长作为 IP寻径“网络地址”,实现网络间路由寻径的新概念 ,使网络具有非常好的可扩展性 .介绍了实验室利用双波长环网构成机群系统验证波长路由的工作进展及关键单元设计 .性能测试表明 ,光互连技术的应用 ,是解决网络带宽不足的理想技术 . 相似文献
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为了满足OFDMA-WLAN系统下行通信中多用户的不同业务需求,提出一种基于公平性和QoS服务保障的资源分配算法.不同的QoS要求被转换成不同的速率要求来计算QoS满意等级;优化目标被修改为公平性驱动的优化函数以提供公平性保障;复杂的资源分配问题被划分为信道分配和功率分配问题,并通过二分图匹配和注水法得到分配结果.与其他算法相比,所提出的算法牺牲了较少的数据速率换取更高的公平性和QoS满意度.仿真结果表明所提算法具有保障QoS和公平性的能力,且在QoS、公平性和速率之间权衡折中时表现更好. 相似文献
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In order to share multimedia transmissions in mesh networks and optimize the utilization of network resources, this paper presents a Two-stage Evolutionary Algorithm （TEA）, i.e., unicast routing evolution and multicast path composition, for dynamic multicast routing. The TEA uses a novel link-duplicate-degree encoding, which can encode a multicast path in the link-duplicate-degree and decode the path as a link vector easily. A dynamic algorithm for adding nodes to or removing nodes from a multicast group and a repairing algorithm are also covered in this paper. As the TEA is based on global evaluation, the quality of the multicast path remains stabilized without degradation when multicast members change over time. Therefore, it is not necessary to rearrange the multicast path during the life cycle of the multicast sessions. Simulation results show that the TEA is efficient and convergent. 相似文献