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131.
132.
基于NS的MPLS模拟器(MNS)组播扩展 总被引:1,自引:0,他引:1
文章首先分析了基于NS的MPLS模拟器(MNS)的结构与原理,并研究了MPLS组播的关键技术,在此基础上.通过对MNS结构的修改,实现了MNS的组播扩展,模拟实验证明了该扩展的可行性与有效性。 相似文献
133.
校园网络教学系统是解决学校课程师资紧缺、充分利用教学资源、提高教学效率的重要手段,目前的远程教学系统中,具有同步、异步两种学习模式.本文通过对二者的分析,设计了直播式多媒体网络教学系统,该系统实现多点、双向实时交互式网络教学,并且实现了教学信息的实时课件化.本文着重介绍直播式多媒体网络教学系统的系统结构及其采用的关键技术. 相似文献
134.
组播是一种被广泛应用的通信技术.组播源认证是组播安全中的重要问题,特别是在有扰信道中实现组播源认证具有很大的挑战性.该文提出一种基于门限密码的链式组播源认证技术,以解决有扰信道上的组播源认证问题.基于组播源认证的安全需求和Dolev-Yao模型,该文首先给出链式组播源认证的安全假设和安全模型;然后结合Shamir的门限秘密共享技术,设计一种适合于有扰信道的组播源认证协议并进行了安全性分析.对协议的仿真结果表明,该文设计的组播源认证在保证较好的通信性能前提下具有良好的抗丢包能力. 相似文献
135.
Multicast hybrid precoding reaches a compromise among hardware complexity, transmission performance and wireless resource efficiency in massive MIMO systems. However, system security is extremely challenging with the appearance of eavesdroppers. Physical layer security (PLS) is a relatively effective approach to improve transmission and security performance for multicast massive MIMO wiretap systems. In this paper, we consider a transmitter with massive antennas transmits the secret signal to many legitimate users with multiple-antenna, while eavesdroppers attempt to eavesdrop the information. A fractional problem aims at maximizing sum secrecy rate is proposed to optimize secure hybrid precoding in multicast massive MIMO wiretap system. Because the proposed optimized model is an intractable non-convex problem, we equivalently transform the original problem into two suboptimal problems to separately optimize the secure analog precoding and secure digital precoding. Secure analog precoding is achieved by applying singular value decomposition (SVD) of secure channel. Then, employing semidefinite program (SDP), secure digital precoding with fixed secure analog precoding is obtained to ensure quality of service (QoS) of legitimate users and limit QoS of eavesdroppers. Complexity of the proposed SVD-SDP algorithm related to the number of transmitting antennas squared is lower compared with that of constant modulus precoding algorithm (CMPA) which is in connection with that number cubed. Simulation results illustrate that SVD-SDP algorithm brings higher sum secrecy rate than those of CMPA and SVD-SVD algorithm. 相似文献
136.
137.
Nathalie Faure Philippe Chrtienne Eric Gourdin Francis Sourd 《Discrete Optimization》2007,4(3-4):360-377
This paper considers the problem of aggregating several multicast sessions. A multicast session is defined as a subset of clients requiring the same information. Besides, each client can require several multicast sessions. A telecommunication network cannot manage many multicast sessions at the same time. It is hence necessary to group the sessions into a limited number of clusters. The problem then consists in aggregating the sessions into clusters to limit the number of unnecessary information sent to clients. The strong relationship of the problems with biclique problems in bipartite graph is established. We then model the problems using integer quadratic and linear programming formulations. We investigate some properties to strengthen the models. Several algorithms are provided and compared with a series of numerical experiments. 相似文献
138.
This paper studies reliability and security of information transmission in networks. We consider the framework of Franklin
and Wright (J. Cryptol. 13(1):9–30, 2000): multicast communication and byzantine adversary. Franklin and Wright studied particular neighbor graphs with neighbor-disjoint paths. The aim of the present work is to drop this assumption and to give necessary and sufficient conditions on the neighbor
graph allowing reliable and secure information transmission. 相似文献
139.
分析介绍了几种典型的IP多播路由协议,如DVMRP、PIM、MOSPF和CBT等,并对这几种IP多播路由协议进行了分析对比。 相似文献
140.
Antonios Alexiou Dimitrios Antonellis Christos Bouras 《Wireless Personal Communications》2008,44(4):455-471
In this paper, we present an efficient scheme for the multicast transmission of the data in the Universal Mobile Telecommunications
System (UMTS). We take advantage of the tree topology of the examined network and we introduce the use of Routing Lists (RLs)
in the nodes of the UMTS. The adoption of these lists leads to the decrement of the transmitted packets and to the efficient
use of network resources in the multicast transmission of the data. We describe in detail the appropriate steps for the successful
multicast transfer of data. Furthermore, we analyze the handling of special cases such as user mobility scenarios. Especially,
the various handover types are examined along with the Serving Radio Network Subsystem relocation procedure. Finally, we implement
our approach in the NS-2 simulator and we present the performance of the multicast mechanism. 相似文献