共查询到19条相似文献，搜索用时 156 毫秒
1.
TANIYAMA Kenta MORII Takeshi KOIZUMI Shinya NOGUCHI Kazuhiro KOTANI Yukihiro KATTO Jiro 《浙江大学学报(A卷英文版)》2006,7(Z1)
We propose an on-demand multiparth routing algorithm in a mobile ad hoc network for video transmission and evaluate its real world performance in video streaming application. There have been a number of multipath routing protocols extended from AODV which is a well-known single path routing protocol. Multipath routing protocols indicate good performance in the reduction of route discovery latency and unnecessary routing packets in simulations. We show that the route establishment using source route lists provided by us (Hu and Johnson, 2002) can reduce the route discovery latency, select stable routes automatically, and work well for live video streaming without limitation of the hop count based approaches. We evaluate this proposed method compared with the original AODV by using eight laptop PCs and demonstrate live streaming experiments. 相似文献
2.
In this paper, the security technology of ad hoc networks is studied.To improve the previous multi-receiver signcryption schemes, an ID-based multi-message and multi-receiver signcryption scheme for rekeying in ad hoc networks is proposed.In this scheme, a sender can simultaneously signcrypt n messeges for n receivers, and a receiver can unsigncrypt the ciphertext to get his message with his own private key.An analysis of this scheme indicates that it achieves authenticity and confidentiality in the random oracle model while being of lower computation and communication overhead.Finally, for the application of our scheme in ad hoc, a threshold key updating protocol for ad hoc networks is given. 相似文献
3.
This paper proposes a novel multichannel medium access control(MAC)protocol based on CDMA that improves network performance and reduces collision probability in wireless ad hoc networks.In the scheme,the code channel is divided into common channel,broadcast channel and several data channels.Simulation results show that the proposed protocol can achieve significantly better performance than the IEEE 802.11 standard. 相似文献
4.
There were two strategies for the data forwarding in the content-centric networking(CCN): forwarding strategy and routing strategy. Forwarding strategy only considered a separated node rather than the whole network performance, and Interest flooding led to the network overhead and redundancy as well. As for routing strategy in CCN, each node was required to run the protocol. It was a waste of routing cost and unfit for large-scale deployment.This paper presents the super node routing strategy in CCN. Some super nodes selected from the peer nodes in CCN were used to receive the routing information from their slave nodes and compute the face-to-path to establish forwarding information base(FIB). Then FIB was sent to slave nodes to control and manage the slave nodes. The theoretical analysis showed that the super node routing strategy possessed robustness and scalability, achieved load balancing,reduced the redundancy and improved the network performance. In three topologies, three experiments were carried out to test the super node routing strategy. Network performance results showed that the proposed strategy had a shorter delay, lower CPU utilization and less redundancy compared with CCN. 相似文献
5.
Optimal congestion control algorithm for ad hoc networks： Penalty function-based approach 总被引：2，自引：0，他引：2
XU Wei-qiang WU Tie-jun 《浙江大学学报(A卷英文版)》2006,7(12):2110-2117
INTRODUCTION Congestion control is a critical issue for ensuring the efficient and fair allocation of network resource among communication flows. In wireline networks, TCP has resolved this issue of concern. However, it was reported that TCP performance in a multihop ad hoc environment degrades severely (Xu and Wu, 2006). Thus, some optimization-based congestion control schemes have been proposed to improve TCP performance in ad hoc networks (Chiang, 2005; Chen et al., 2005; Lee et a… 相似文献
6.
A novel control strategy for the load converter supplying the unbalanced AC load in a DC isolated distribution system is presented. The control algorithm results in balanced and sinusoidal load voltages under unbalanced AC loading. The unbalanced load is characterized in the d-q-0 rotating coordinate based on symmetrical sequence components. Also, the mathematical model of the load converter in both a-b-c and d-q-0 coordinates is derived by using the average large signal model. Then, two control strategies for the load converter are presented. The first one uses the conventional d-q-0 controller to ensure the voltage and current regulation. The second one is a newly proposed control strategy based on the decomposition of the voltage and current into in- stantaneous positive, negative, and zero sequences. These three sequences are controlled independently in their own reference frames as DC signals. The performance of the load converter using these two control strategies is compared. Simulation results show the validity and capability of the newly proposed control strategy. 相似文献
7.
Reputation-based linear cooperation for spectrum sensing in cognitive radio networks 总被引：1，自引：0，他引：1
We propose a reputation-based cooperative spectrum sensing scheme in cognitive radio （CR） networks to solve the uncertainty resulting from the multipath fading and shadowing effect. In the proposed scheme, each cooperative CR user has a reputation degree that is initialized and adjusted by the central controller, and used to weight the sensing result from the corre- sponding CR user in the linear fusion process at the central controller. A simple method for adjusting the reputation degree of CR users is also presented. We analyzed and evaluated the detection performance of the reputation-based cooperative spectrum sensing scheme. Simulation results showed that our proposed scheme alleviates the problem of corrupted detection resulting from destructive channel conditions between the primary transmitter and the CR user. The performance of our proposed scheme was improved compared to the average-based linear cooperation scheme, and was similar to that of the optimal linear cooperation scheme with feasible computational complexity. Moreover, our proposed scheme does not require knowledge of channel statistics. 相似文献
8.
Jázef LUBZCZ 《浙江大学学报(A卷英文版)》2008,9(10):1309-1317
This paper presents an analytical saturation throughput model of IEEE 802.11DCF （distributed coordination function） with basic access in ad hoc mode. The model takes into account freezing of the backofftimer when a station senses busy channel. It is shown that taking into account this feature of DCF is important in modeling saturation throughput by yielding more accurate and realistic results than models known from literature. The proposed analytical model also takes into account the effect of transmission errors. All essential features of the proposed analytical approach are illustrated with numerical results. The presen- tation of the model is proceeded by an overview of approaches to IEEE 802.11 network performance evaluation presented in the literature. 相似文献
9.
ZUO Dong-hong DU Xu YANG Zong-kai 《浙江大学学报(A卷英文版)》2007,8(8):1191-1198
Media streaming delivery in wireless ad hoc networks is challenging due to the stringent resource restrictions,po-tential high loss rate and the decentralized architecture. To support long and high-quality streams,one viable approach is that a media stream is partitioned into segments,and then the segments are replicated in a network and served in a peer-to-peer(P2P) fashion. However,the searching strategy for segments is one key problem with the approach. This paper proposes a hybrid ants-like search algorithm(HASA) for P2P media streaming distribution in ad hoc networks. It takes the advantages of random walks and ants-like algorithms for searching in unstructured P2P networks,such as low transmitting latency,less jitter times,and low unnecessary traffic. We quantify the performance of our scheme in terms of response time,jitter times,and network messages for media streaming distribution. Simulation results showed that it can effectively improve the search efficiency for P2P media streaming distribution in ad hoc networks. 相似文献
10.
The flooding distance is an important parameter in the design and evaluation of a routing protocol,which is related not only to the delay time in the route discovery,but also to the stability and reliability of the route.In this paper, the average flooding distance (AFD) for a mobile ad hoc network (MANET) in a random graph model was given based on the dynamic source routing (DSR) protocol.The influence of spatial reuse on the AFD was also studied.Compared with that in the model without the spatial reuse,the AFD in the model with the spatial reuse has much smaller value,when the connetivity probability between nodes in the network is small and when the number of reused times is large.This means that the route discovery with the spatial reuse is much more effective. 相似文献
11.
MANETs中基于链路有效性预测的高效AODV路由协议 总被引：1，自引：0，他引：1
针对传统AODV路由协议中周期性Hello消息广播机制会造成协议效率低下的问题,提出了一种利用无线链路有效性预测来降低Hello控制报文的新策略.首先给出了适用于视距无线传输环境下新的链路有效性预测模型,根据此模型所预测的无线链路生命周期来动态更新AODV路由协议中的Hello Interval配置参数,从而实现在不同链路稳定性下以不同频率广播Hello消息的目的.仿真结果表明,相比于采用周期性Hello消息广播机制的原协议而言,改进协议有效减少了不必要的报文开销,并在平均端到端时延和协议效率这2个性能指标上都获得了明显改善. 相似文献
12.
无线ad hoc网络最小均方负载均衡路由算法 总被引：1，自引：0，他引：1
Routing algorithm is a challenge for a mobile ad hoc network (MANET), but current routing protocols for MANETsconsider the path with minimum number of hops as the optimal path to a given destination. This strategy does not balancethe traffic load over a MANET, and may result in some disadvantages such as creating congested area, depleting power fasterand enlarging time delay in the nodes with heavy duties. In this paper, we propose a routing scheme that balances the loadover the network by selecting a path based on its mean load-square, the proposed routing metric can reflect not only the loadof the path, but also the load distribution along the path. Simulation results show effectiveness of this routing scheme onbalancing the load over all nodes in the network. 相似文献
13.
移动自组网多路径路由具有有效使用带宽、均衡负载和增加传输可靠性等方面的优势。路由发现是路由协议的重要组成部分,分析了设计多路径路由协议的路由发现部分的关键问题及不同策略,对近几年国内外提出的多路径路由协议在路由发现部分进行了比较,指出了多路径路由发现中需要进一步研究的问题。 相似文献
14.
一种增强移动自组网Internet连接的改进型方案 总被引：1，自引：0，他引：1
针对移动自组网因单向链路以及盲目转播网关发现分组而造成的与Internet互联性能下降,提出了一种增强型互联方案.同时结合了先应和后应网关发现策略优点的混合网关发现策略被用来获取良好的Internet连接并保持低开销.而通过交换携带有额外增加的对称邻居节点列表和非对称邻居节点列表字段的AODV hello分组,单向链路得以从路由计算中予以清除而广播风暴也同时得到抑制.基于ns-2的仿真结果表明此改进型Internet连接方案在单向链路数量及节点移动速度均变化的应用环境下能取得较其他方案为优的互联性能. 相似文献
15.
葛文英 《安阳师范学院学报》2006,(5):45-48
目前,移动Ad Hoc网络越来越受到人们的重视。在Ad Hoc网络中,路由协议的性能优劣是一个很重要的问题。目前的协议大体可分为两类:表驱动类和按需驱动类路由协议。研究表明:表驱动类的路由协议带来了大量的路由开销,对于网络带宽比较紧张的Ad hoc网络环境,按需路由协议是更好的选择。 相似文献
16.
针对Ad Hoc网络路由问题,本文将备份路径加入到AODV（ad hoc on-demand distance-vector）路由协议中,使用原AODV中的RREP（Route Reply）控制信号和Data包来建立网状的备份路径,建立一种适应动态拓扑网络的路由协议,从而改善网络性能.采用面向对象的建模技术在OMNET＋＋软件平台上进行了仿真,结果证明该方法提高了网络的QoS,为Ad-hoc网络路由协议的发展提供了一个新思路. 相似文献
17.
Cross-layer design of energy-saving AODV routing protocol 总被引：1，自引：0，他引：1
Since most ad hoc mobile devices today operate on batteries, the power consumption becomes an important issue. This paper proposes a cross-layer
design of energy-aware ad hoc on-demand distance vector (CEAODV) routing protocol which adopts cross-layer mechanism and energy-aware metric to improve
AODV routing protocol to reduce the energy consumption and then prolong the life of the whole network. In CEAODV, the link
layer and the routing layer work together to choose the optimized transmission power for nodes and the route for packets.
The link layer provides the energy consumption information for the routing layer and the routing layer chooses route accordingly
and conversely controls the link layer to adjust the transmission power. The simulation result shows that CEAODV can outperform
AODV to save more energy. It can reduce the consumed energy by about 8% over traditional energy-aware algorithm. And the performance
is better when the traffic load is higher in the network. 相似文献
18.
随着移动自组织网络(MANET)的应用领域日益扩大,要求它必须提供一定的服务质量(QoS)保证,而QoS路由协议是MANET支持QoS的一个关键理论和技术,也是目前的一个研究热点。本文对当前自组织网络的QoS主要路由协议进行了详细的分析与研究,并从路由机制、单向链路的支持、多播功能、QoS参数选择以及节能几个方面进行了比较和分析;最后指出了今后的研究方向。 相似文献
19.
DSR路由协议改进方案分析 总被引：1，自引：0，他引：1
罗莉琼 《湖南广播电视大学学报》2008,(2):71-72
移动无线自组织网络具有多跳无线连接的特点,在这样的网络中如何有效的提高路由是一个挑战性的问题。本文提出在DSR协议中对不连贯的路由使用两种多路由技术评价其性能的优劣,这两种方案对评价按需路由协议的性能是有用的。 相似文献