共查询到20条相似文献,搜索用时 140 毫秒
1.
2.
本文提出一种改进的MobiCast方案来实现移动IP组播通信,主要解决MobiCast方案中进行区域间切换时组播数据包丢失问题。与MobiCast方案相比,在区域外地代理(DomainForeignAgent,DFA)处引入一种缓存的机制。当移动节点发生区域间切换时,移动节点的旧区域外地代理采用隧道技术,将移动节点的信息和缓存的组播数据包发送给移动节点的新区域外地代理处,减少移动节点进行区域间切换时丢失的组播数据包。 相似文献
3.
无线局域网采用移动IP实现移动性管理.移动IP切换存在切换时延大,数据包易丢失的问题.切换时延由移动检测时延和注册时延组成,而移动检测时延在其中占主要部分.文章提出了一种移动检测优化方案,采用了自适应绑定的算法,同时充分考虑了域内小范围高频度切换的情况,使移动节点在无线局域网环境中进行快速有效的切换. 相似文献
4.
5.
6.
有两种比较常用的减少切换时延的方法.第一种是通过分层管理的架构来减少家乡网络的注册时间,第二种是通过地址预先配置来减小地址长度的方法来解决延迟的快速切换机制。S-MIP切换方法是建立在分层和快速切换方法之上的。它能够实现与L2层相似的较少的数据包丢失和切换的时延。 相似文献
7.
设计了一种能够在3G与WLAN融合网络中智能切换的双模终端模型.为了实现两种网络之间的无缝切换,提出了网络接口选择算法.该算法通过提前注册和认证机制减少了垂直切换时延,并采用提前切换的方法减少了垂直切换时数据包丢失.仿真结果验证了设计和算法具有良好性能. 相似文献
8.
9.
10.
基于mSCTP,通过分析影响垂直切换性能的两个问题,即切换到新路径上的慢启动现象导致的吞吐量骤降,以及由于原无线信号的迅速衰减使得SACK丢失导致的多余重传,引入一种垂直切换性能优化的改良方案mSCTP-IPVHO。通过仿真表明,mSCTP-IPVHO能在一定程度上优化异构网络垂直切换性能。 相似文献
11.
An end-to-end multipath smooth handoff scheme for stream media 总被引:2,自引:0,他引:2
Yi Pan Meejeong Lee Jaime Bae Kim Suda T. 《Selected Areas in Communications, IEEE Journal on》2004,22(4):653-663
Supporting transmission of stream media over wireless mobile networks is often difficult because packets may be lost due to the rerouting of packets during handoff, and also because bursts of packet loss may occur during handoff due to the disparity in the amount of available bandwidth among different cells. In this paper, we propose an end-to-end multipath handoff scheme that provides smooth handoff for stream media in wireless networks with different amounts of available bandwidth from cell to cell. In the proposed scheme, multiple paths are established during handoff to reach a mobile destination node. The stream media sources are equipped with an adaptive multilayer encoder, and important layers in the encoded video stream are duplicated and transmitted over multiple paths during handoff. The effectiveness of the proposed multipath handoff scheme is verified and compared with existing schemes through extensive simulations. The simulation results show that the proposed scheme provides higher throughput and better quality for stream media. 相似文献
12.
Non‐preemptive Queueing Model of Spectrum Handoff Scheme Based on Prioritized Data Traffic in Cognitive Wireless Networks
下载免费PDF全文
![点击此处可从《ETRI Journal》网站下载免费的PDF全文](/ch/ext_images/free.gif)
In this study, a non‐preemptive M/G/1 queueing model of a spectrum handoff scheme for cognitive wireless networks is proposed. Because spectrum handoff gives secondary users an opportunity to carry on their transmissions, it is crucially important to determine the actions of primary users. In our queueing model, prioritized data traffic is utilized to meet the requirements of the secondary users. These users’ packets are categorized into three different priority classes: urgent, real‐time, and non‐real time. Urgent data packets have the highest priority, while non‐real time data packets have the lowest priority. Riverbed (OPNET) Modeler simulation software was used to simulate both reactive and proactive decision spectrum handoff schemes. The simulation results were consistent with the analytical results obtained under different load and traffic conditions. This study also revealed that the cumulative number of handoffs can be drastically decreased by exploiting priority classes and utilizing a decent spectrum handoff strategy, such as a reactive or proactive decision‐based strategy. 相似文献
13.
Ikram Smaoui Faouzi Zarai Mohammad M. Banat Lotfi Kamoun 《Wireless Personal Communications》2010,54(3):417-445
Vertical handoff is one of the most important issues for the next generation heterogeneous wireless networks. However, in
many situations, unbeneficial vertical handoffs occur across intersystem heterogeneous networks cause network performance
degradation. Therefore, we propose a novel configuration architecture that can be deployed in the next generation of wireless
networks. Second, we propose a predictive and adaptive Vertical Handoff Decision Scheme that optimizes the handoff initiation
time as well as selection of the most optimal network. The proposed vertical handoff decision algorithm considers the technology
type as well as the Signal to Interference Ratio (SIR), the Mobile Station (MS) velocity, the user preferences, the applications
requirements and the terminal capabilities as the most important factors to make vertical handoff decision. In order to minimize
handoff costs, the proposed decision algorithm uses the dwell timer concept. The handoff costs are analyzed in terms of unnecessary
and unbeneficial handoffs rate.The simulation results show that the reduction of unnecessary handoffs proposed in our vertical
handoff decision scheme reduces the handoff blocking probability, the packets loss rate and the handoff overhead 相似文献
14.
The Research on Handoff Strategy in Beyond 3G Wireless Networks 总被引:2,自引:3,他引:2
CUI Hong-yan TIAN Hui XU Hai-bo ZHANG PingCollege of Telecommunication Engineering Beijing University of Posts Telecommunications Beijing P.R. China 《中国邮电高校学报(英文版)》2006,13(2):26-30
1Introduction TheBeyondThirdGenerationMobileSystems(B3G)isabrandnewmobilitycommunicationsystembasedon IPv6corenetwork.B3Gcanprovidevariousservices withtheendtoendQoSguaranteeflexible,andthe transferdatarate150Mb/s.Itspeakratecanreach30~50Mb/sinlargecover… 相似文献
15.
《电子学报:英文版》2017,(5):1032-1040
Wireless LAN controller (WLC) is used to manage and control Access points (APs) in Wireless local area network (WLAN).Proxy mobile IPv6 (PMIPv6) protocol supports network-layer mobility in WLC based WLAN.However,it introduces extra delay in delivering packets from the APs to the WLC.We use Mobile access gateway (MAG) chain to reduce packet delay.The handoff delay and packet delivery delay under the proposed scheme are derived,based on which we formulate the delay minimization problem whose solution leads to the optimal MAG chain length.Numerical analysis results indicate that the proposed scheme outperforms the existing scheme in terms of delay in the case when the delay between Local mobility anchor (LMA) and WLC is relatively greater than the delay between two neighboring WLCs.The proposed scheme is able to reduce packet loss resulting from the traditional handoff procedure introduced in the PMIPv6 protocol and that due to delay limitation. 相似文献
16.
Interworking issues between Universal Mobile Telecommunication System (UMTS) and Wireless Local Area Network (WLAN) have become
a great matter of interest as an increasing number of mobile internet users require broadband wireless access to IP services
in the wide area. In this paper, we present a practical UMTS–WLAN interworking architecture based on 3GPP standards and propose
a seamless handoff scheme that guarantees low delay and low packet loss during UMTS–WLAN handoff. For low handoff delay, the
proposed handoff scheme performs pre-registration and pre-authentication processes before layer 2 handoff. Moreover, it uses
packet buffering and forwarding functions in order to reduce packet loss during the handoff period. On the above basis, detailed
signaling procedures are presented, together with system requirements when a mobile terminal moves from UMTS to WLAN and vice-versa.
Numerical results show that the proposed scheme performs well with respect to signaling cost, handoff delay, and packet loss
compared with conventional schemes. 相似文献
17.
In this paper, micro mobility problems in handoff binding latency in Mobile IPv6 and the enhanced Cellular Mobile IPv6 (CMIv6) are investigated using a new extension protocol. Frequent and fast movements usually characterize micro mobility. An enhanced handoff extension is adopted to solve the Mobile IPv6 handoff break in a micro mobility environment. The basic idea involves using the new field in the IPv6 header, flow label, to assist the foreign router delivering packets to the mobile node. The Foreign Home Agent (FHA) is a new defined node in this proposition. FHA can accurately deliver packets according to the mobile node IP address even though the new binding messages have not arrived at the CN. The simulations shown in this paper prove that the enhanced CMIv6 scheme can minimize packet loss during handoffs. 相似文献
18.
Chung‐Ming Huang Meng‐Shu Chiang Chin‐Wei Lin 《Wireless Communications and Mobile Computing》2009,9(9):1194-1205
Mobile IP (MIP) defines a mobility management for mobile users to continuously access data when the currently attachment is changed to another network. However, when mobile node (MN) roams between network segments, the handoff latency results in packet losses and transmission delay. In this paper, we propose a multihomed fast handoff scheme (MFH‐MIP) to decrease the handoff cost. In the proposed MFH‐MIP scheme, each MN is implemeted with the link layer trigger and multihomed techniques. Based on the link layer trigger, MN can collect signal strengths of nearby access points (APs) and switch to a new link automatically when the old link becomes unsuitable to connect. Using the multihomed technique, MN can prepare for handoff using two (or more) interfaces, in which (i) one is connected with the old link to receive packets and (ii) the other one is used to access nearby APs and select the most suitable one as the new link, in parellel. In this way, MN can continuously transmit and receive packets during handoff. Based on the proposed method, MN can roam smoothly among different networks in the wireless environment. Copyright © 2008 John Wiley & Sons, Ltd. 相似文献
19.
Because a wireless ad hoc network does not have a fixed backbone network and the mobile base station moves randomly, the conventional channel allocation scheme cannot efficiently predict group mobility and is not feasible to support a burst handoff traffic due to group mobility. In this paper, we propose an channel allocation scheme to solve this problem. Our scheme efficiently support burst handoff using guard channel and hello message in wireless ad hoc network with group mobility. We developed an analytical Markov model for the proposed scheme and evaluate our scheme in terms of new call and handoff blocking probability and channel utilization via simulation study. Simulation results show that our scheme offers better performance than the conventional schemes. 相似文献
20.
Yuh‐Shyan Chen Chih‐Shun Hsu Ching‐Hsueh Cheng 《International Journal of Communication Systems》2014,27(11):3042-3063
The goal of the network mobility management is to effectively reduce the complexity of handoff procedure and keep mobile devices connecting to the Internet. When users are going to leave an old subnet and enter a new subnet, the handoff procedure is executed on the mobile device, and it may break off the real‐time service, such as VoIP or mobile TV, because of the mobility of mobile devices. Because a vehicle is moving so fast, it may cause the handoff and packet loss problems. Both of the problems will lower down the throughput of the network. To overcome these problems, we propose a novel network mobility protocol for vehicular ad hoc networks. In a highway, because every car is moving in a fixed direction at a high speed, a car adopting our protocol can acquire an IP address from the vehicular ad hoc network through the vehicle‐to‐vehicle communications. The vehicle can rely on the assistance of a front vehicle to execute the prehandoff procedure, or it may acquire a new IP address through multihop relays from the car on the lanes of the same or opposite direction and thus may reduce the handoff delay and maintain the connectivity to the Internet. Simulation results have shown that the proposed scheme is able to reduce both the handoff delay and packet loss rate. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献