共查询到20条相似文献,搜索用时 359 毫秒
1.
针对由超密集异构无线网络的超高动态性而引起掉话率不断增长的问题,并考虑到以往基于模糊逻辑相关垂直切换算法的较大时间开销,该文提出一种改善用户体验的垂直切换算法。首先利用5G核心访问和移动管理功能发现终端附近的所有候选网络,同时,利用自组织网络技术的环境感知能力,随时监测网络的运行状况,主动维护网络之间的邻居关系表。然后,引入动态模糊神经网络(DFNN)算法来执行切换判决,将获取到的网络参数数据作为该系统的输入,动态生成对垂直切换有效的规则库,经学习之后,计算得到输出判决值,从而为终端选择最佳接入网络。最后,仿真结果表明,该算法能够明显改善垂直切换过程中的掉话情况,降低切换失败概率。同时,与其他同类算法的时间消耗相比,该算法能够维持在一个较低的水平。 相似文献
2.
车辆异构网络中预测垂直切换算法 总被引:3,自引:0,他引:3
在车辆异构网络中,针对垂直切换决策时刻之后网络状态的动态变化,提高切换性能问题,提出一种基于马尔可夫过程的预测垂直切换(M-VHO)算法。算法考虑了切换决策后网络状态的动态变化对车辆终端服务质量(QoS)的影响。其基本思路是:在需要垂直切换时,利用马尔可夫过程的转移概率预测未来网络状态的变化;另外,采用模糊逻辑方法确定评价属性参数权重;最后,比较切换决策、切换执行和切换之后时刻的总收益来优化选择最佳切换网络。仿真结果证明,该算法在确保较高负载均衡的情况下,可有效改进车辆终端的平均阻塞率及丢包率,降低乒乓效应,确保了车辆终端的QoS。 相似文献
3.
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
4.
随着无线异构网络的融合,移动性管理技术成为其关键问题,而切换管理又是移动性管理的重要部分。针对垂直切换管理提出了一种基于运动趋势的模糊逻辑垂直切换算法。算法分为预判定、模糊逻辑控制及切换判决3个过程。首先,在预判定阶段根据MN的运动趋势及接收信号强度滤除掉不适宜接入WLAN的网络信息,从而有效减少不必要的数据量和系统开销;其次,将接收信号强度、网络的可用带宽和网络开销送入模糊逻辑控制器,通过参数的归一量化最终得到网络综合性能值(VCPN);最后,通过综合考虑VCPN和驻留时间来进行网络切换判决。仿真结果显示,该算法能够有针对性地做出切换判决,有效消除乒乓效应,提高网络切换性能。 相似文献
5.
异构无线网络中基于SINR和层次分析法的SAW垂直切换算法研究 总被引:5,自引:0,他引:5
B3G或者4G无线网络体系致力于集成各种异构无线接入网络,其中一个主要的设计课题是支持垂直切换的研究。该文将多属性QoS考虑在内,针对各业务特点,提出一种基于SINR(信干噪比)和层次分析法(AHP)的SAW(简单加权法)垂直切换算法(SASAW)。它综合考虑SINR的影响以及要获得同等数据速率情况下,目标网络需要的等效SINR数值、用户通信代价、网络可用带宽等来构造属性矩阵做切换判决。为了评估性能,考虑3GPP定义的4类业务,利用层次分析法中的特征向量法来决定各个QoS属性之间的权重关系,构造比较判决矩阵并检验其一致性;根据判决矩阵,利用特征根法获得权重向量;最后根据属性矩阵和权重向量,利用SAW垂直切换算法进行判决。通过对算法的通过率、丢话率、垂直切换次数、平均用户代价等的性能比较,结果表明该文提出的算法能够根据各业务特点综合考虑各属性间关系,获得优良的系统性能。 相似文献
6.
A Simple and Robust Vertical Handoff Algorithm for Heterogeneous Wireless Mobile Networks 总被引:2,自引:0,他引:2
Daojing He Caixia Chi Sammy Chan Chun Chen Jiajun Bu Mingjian Yin 《Wireless Personal Communications》2011,59(2):361-373
Wireless networking is becoming an increasingly important and popular way of providing global information access to users
on the move. One of the main challenges for seamless mobility is the availability of simple and robust vertical handoff algorithms,
which allow a mobile node to roam among heterogeneous wireless networks. In this paper, motivated by the facts that vertical
handoff procedure is done on mobile nodes and battery power may be one crucial parameter for certain mobile nodes, a simple
and robust two-step vertical handoff decision algorithm is proposed for heterogeneous wireless mobile networks. To the best
of our knowledge, this is the first vertical handoff algorithm that takes the classification of mobile nodes into consideration,
one is resource-poor mobile nodes, and the other is resource-rich mobile nodes. This new feature makes it more applicable
in the real world. In addition, dynamic new call blocking probability is firstly introduced by this paper to make handoff
decision for wireless networks. The experiment results have shown that the proposed algorithm outperforms traditional algorithms
in bandwidth utilization, handoff dropping rate and handoff rate. 相似文献
7.
在超密集异构无线网络中,针对城区交通高峰期,大规模车载终端短时间聚集性移动引起的网络拥塞问题,该文提出一种考虑负载均衡和用户体验(LBUE)的垂直切换算法。首先,引入网络环境感知模型预测网络未来的拥塞程度,并提出一个融合自组织网络的网络架构,缓解网络拥塞。其次,定义业务适应度和负收益因子,并提出一种基于秩和比(RSR)的自适应切换判决算法,为用户筛选出当前环境下满意度最高的目标网络。实验结果表明,该算法能够有效降低终端接入网络的阻塞率和掉话率,实现网络间负载均衡并提升用户体验。 相似文献
8.
In order to enhance the quality of vertical handoff in an overlay wireless network, multiple attributes are taken into account when optimizing the vertical handoff decision including user-based and network-based QoS factors. In this paper, we develop a novel vertical handoff algorithm in an integrated 3G cellular and Wireless LAN networks. The proposed algorithm can adjust the weight of each QoS attribute dynamically as the networks change, trace the network condition and choose the optimal access point at transient regions. Simulation results show that this algorithm is able to provide accurate handoff decision, resulting in small unnecessary handoff numbers, good performance of throughput and handoff delay in heterogeneous environments. 相似文献
9.
10.
Handoff decision making is one of the most important topics in wireless heterogeneous networks architecture as there are many
parameters which have to be considered when triggering handoff and selecting suitable access point. More intelligent approaches
which reckon user profiles, application requirements, and network conditions must be improved so that desired performance
results for both user and network could be provided. In this paper we introduce a new adaptive vertical handoff decision making
algorithm in which fuzzy membership functions are optimized by means of genetic algorithm. Genetic algorithm is an adaptive
search technique based on natural selection and genetic rules. In addition to that, it takes places in various scientific
applications and can be used to adjust the membership functions in fuzzy systems. The purpose of the study is to adjust the
shape of fuzzy membership functions, properly, using genetic algorithm in order to achieve optimum handoff performance. The
results show that, compared to the several different algorithms performance of the proposed approach with genetic algorithm
is significantly improved for both user and network in terms of number of handoff while the other requirements are still satisfied. 相似文献
11.
12.
在异构5G网络中,针对切换算法稳健性差引起的切换准确率低的问题,提出一种基于区间标记判决的稳健垂直切换算法.首先,引入中位值平均滤波法,获取更准确的网络参数.其次,基于参数波动特征分析,提出区间标记判决算法,保证候选网络筛选通过率和准确率的同时,提高区间标记判决算法的稳健性.再次,根据移动终端传输层需求,结合终端运动趋势,分别使用不同权值的效用函数获得最佳目标网络.最后,仿真结果表明,该算法能够有效提升切换触发和网络筛选的准确率,降低切换失败率和乒乓效应,提高系统吞吐量,并能够根据移动终端的需求选择最佳目标网络. 相似文献
13.
14.
针对异构无线网络中用户希望通过较低的花费获取最满意的网络服务的需求,本文提出了一种以用户为中心的成本感知网络切换方案.首先,根据用户能够获取到的网络传输速率建立用户服务满足度模型,并结合归一化的网络费用,将网络切换问题转化为一个多目标优化问题.考虑到网络阻塞是由于大量用户同时选择同一个网络导致的,将这种背景下的用户决策行为转化为EI Farol酒吧问题,通过求解该问题纳什均衡状态下的用户获取网络服务的概率来得到用户服务满足度的期望值.最后,通过考虑用户服务满足度回报率将所构建的多目标优化问题转化为一个最大化问题.仿真结果表明本文算法能够提高网络总吞吐量,降低用户切换阻塞率,使网络负载更加均衡. 相似文献
15.
In this paper, we propose the signal strength ratio (SSR) based vertical handoff (VHO) algorithms and the averaged received signal strength (ARSS) based VHO algorithms for integrated networks of wireless local area network (WLAN) and 3G network. The performance of our proposed VHO algorithms with hysteresis and dwell timer approaches has been investigated for two different topologies of integrated heterogeneous network. Two different network topologies consider two different types of radio cell arrangement. A mobile terminal (MT) is moving within the coverage area of WLAN and 3G with constant velocity. The received signal strength at the MT of interest is measured at different sampling instant. The received signal strength with other additional parameters is used to determine the condition of VHO. We evaluate the decision delay, and the number of vertical handoffs between WLAN and 3G network using the proposed VHO algorithms. We compare the performance of our proposed VHO algorithms with existing RSS based VHO algorithm. Our proposed SSR and ARSS based VHO algorithms provide less decision delay as compared to existing RSS based VHO algorithm. Further, ARSS with dwell timer based VHO algorithm provides better performance than other VHO algorithms. 相似文献
16.
针对全IP核心网络的不同无线接入技术,提出一种基于预判决模糊逻辑的垂直切换算法.引入预判决方法有效减少不必要的数据量和系统开销.采用前向差分预测能够较准确地预测出下一时刻的信号强度,提高了切换触发速度和切换判决精度.采用模糊逻辑的方法,以接收信号强度、预测信号强度及可用带宽作为网络参量设计模糊逻辑控制器,进而采用归一量化的方法改进模糊逻辑系统,得到网络的综合性能值进行垂直切换判决.仿真分析表明,本文提出的算法能够较准确做出切换判决,有效消除乒乓效应,提高系统性能. 相似文献
17.
18.
19.
Intelligent Handoff for Mobile Wireless Internet 总被引:6,自引:0,他引:6
Jon Chiung-Shien Wu Chieh-Wen Cheng Nen-Fu Huang Gin-Kou Ma 《Mobile Networks and Applications》2001,6(1):67-79
This paper presents an intelligent mobility management scheme for Mobile Wireless InterNet – MWIN. MWIN is a wireless service networks wherein its core network consisting of Internet routers and its access network can be built from any Internet-capable radio network. Two major standards are currently available for MWIN, i.e., the mobile IP and wireless LAN. Mobile IP solves address mobility problem with the Internet protocol while wireless LAN provides a wireless Internet access in the local area. However, both schemes solve problems independently at different layers, thereby some additional problems occur, e.g., delayed handoff, packet loss, and inefficient routing. This paper identifies these new problems and performs analyses and some real measurements on the handoff within MWIN. Then, a new handoff architecture that extends the features of both mobile IP and wireless LAN handoff mechanism was proposed. This new architecture consists of mobile IP extensions and a modified wireless LAN handoff algorithm. The effect of this enhancement provides a linkage between different layers for preventing packet loss and reducing handoff latency. Finally, some optimization issues regarding network planning and routing are addressed. 相似文献
20.
Chi Sun Enrique Stevens-Navarro Vahid Shah-Mansouri Vincent W. S. Wong 《Wireless Networks》2011,17(4):1063-1081
The 4th generation wireless communication systems aim to provide users with the convenience of seamless roaming among heterogeneous
wireless access networks. To achieve this goal, the support of vertical handoff is important in mobility management. This
paper focuses on the vertical handoff decision algorithm, which determines the criteria under which vertical handoff should
be performed. The problem is formulated as a constrained Markov decision process. The objective is to maximize the expected
total reward of a connection subject to the expected total access cost constraint. In our model, a benefit function is used
to assess the quality of the connection, and a penalty function is used to model the signaling incurred and call dropping.
The user’s velocity and location information are also considered when making handoff decisions. The policy iteration and Q-learning
algorithms are employed to determine the optimal policy. Structural results on the optimal vertical handoff policy are derived
by using the concept of supermodularity. We show that the optimal policy is a threshold policy in bandwidth, delay, and velocity.
Numerical results show that our proposed vertical handoff decision algorithm outperforms other decision schemes in a wide
range of conditions such as variations on connection duration, user’s velocity, user’s budget, traffic type, signaling cost,
and monetary access cost. 相似文献