5G无线接入网络的异构切换技术研究

5G时代悄然而至,在这一时代背景中,多种通信技术巧妙融合,以此满足用户个性化服务需求,并丰富用户服务体验。其中,异构切换技术作为5G无线接入网络发展的产物,该技术在网络性能优化、定制化服务需求迎合等方面起到重要作用。本文在异构无线网络简介的基础上,全面分析异构切换技术方案,最后针对这一技术重点探究,以期为技术研究者和5G网络实践者提供借鉴,从而扩大异构切换技术推广范围。

无锡电视台播出数据库异构切换的实现方案

本文介绍了无锡电视台播出数据库由原来的Oracle向SQL Server异构迁移的过程,以及迁移的原因,并且为此建立的迁移方案和应急预案。还介绍了在数据迁移中遇到的困难和解决办法,为同行业播出系统在线异构切换核心数据库提供参考。

基于MIH的FMIPv6切换方案的改进

在下一代异构网络环境中为移动用户提供无缝切换以及更优的体验质量是人们面临的一大挑战。尽管FMIPv6一定程度上减小了切换的时延,但还是存在切换发起时延过大,以及无法满足垂直切换的需求等缺点。提出了一种基于IEEE 802.21 MIH(与介质无关切换)服务的FMIPv6改进机制。利用MIH信息服务优化了接入路由发现以及接入点(AP)发现过程。利用MIH事件服务优化了FMIPv6的切换过程。通过性能分析可以发现,改进机制减小了切换发起时间增加了预应式切换的可能性,减小了AP发现时间,同时也减小了切换时延。

垂直切换的策略研究

下一代无线网络中,异构切换技术是融合多个异构接入网络的关键技术之一。近年来,随着无线通信技术的蓬勃发展,如何使用多个异构网络接口达到无缝的异构切换成为研究热点。多个接口可以采用不同的触发机制和使用规则,这将需要不同的协议实现支持并带来不同的实际切换性能。文章对异构切换中的多接口使用机制以及触发规则进行详细研究,并对不同的多接口使用机制和异构切换触发机制的4种不同组合进行仿真比较。从仿真结果可以看到,切换过程中采用链路层的信息能够及时触发即将发生的切换,另外,如果采用多个接口预先建立连接的机制,能够最大限度的减少切换延时。因此,这两种机制的组合能够带来最佳的切换效果。

异构无线网络终端服务感知的动态负载均衡机制

异构无线网络负载均衡是提高网络服务质量的关键技术之一。现有负载均衡机制大多没有考虑用户的个性化业务在请求网络资源时存在的差异,同时缺乏一种用户满意度保障机制。针对这一问题,提出一种终端服务感知的动态负载预先均衡机制。首先,采用模糊数学的推理方法,计算出终端对各个候选网络的接入期望值。在此基础上,充分考虑各候选网络的资源拥塞状况,有选择性地将该终端用户业务链接切换到低资源拥塞率、高接入期望值网络中,从而缓解网络中的局部热点,提高网络资源有效利用率与用户满意度。仿真结果表明,该机制能够显著均衡网络中各个无线接入点的工作负荷,有效减少拥塞发生的概率,改善用户的网络体验。

一种基于SIP与移动IPV6的异构网络切换方法

随着移动通信技术的发展,诞生了各种可供接入的网络,如GPRS,WALN等。它们传输速率和原理各不相同,不同异质接入网络之间的切换已经成为对下一代无线网络的一个基本要求。本文介绍了一种新的切换机制,首先分别介绍了SIP技术与移动IPv6技术的原理,然后结合SIP与移动IPv6技术提出一种全新的无缝切换机制,最后总结并提出了有待进一步研究的相关问题。

A Novel Vertical Handoff Algorithm with Dynamic Weights in Wireless Heterogeneous Networks

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.

A dynamic programming algorithm for network selection in 3G/WLAN

An essential characteristic of the 4th Generation(4G) wireless networks is integrating various heterogeneous wireless access networks.This paper considers the network selection for both admission and handoff strategy problems in heterogeneous network of 3G/WLAN.A novel dynamic programming algorithm is proposed by taking heterogeneous network characteristics,user mobility and different service types into account.The specificity of our approach is that it puts the situations in a new model and makes decisions in stages of different states.Simulation results validate that the proposed scheme can obtain better new call blocking and handoff dropping probability performance than traditional schemes while ensuring quality-of-services(QoS) for both real-time and data connections.

An Optimized Vertical Handoff Algorithm Based on Markov Process in Vehicle Heterogeneous Network

In order to solve the problem the existing vertical handoff algorithms of vehicle heterogeneous wireless network do not consider the diversification of network's status, an optimized vertical handoff algorithm based on markov process is proposed and discussed in this paper. This algorithm takes into account that the status transformation of available network will affect the quality of service(Qo S) of vehicle terminal's communication service. Firstly, Markov process is used to predict the transformation of wireless network's status after the decision via transition probability. Then the weights of evaluating parameters will be determined by fuzzy logic method. Finally, by comparing the total incomes of each wireless network, including handoff decision incomes, handoff execution incomes and communication service incomes after handoff, the optimal network to handoff will be selected. Simulation results show that: the algorithm proposed, compared to the existing algorithm, is able to receive a higher level of load balancing and effectively improves the average blocking rate, packet loss rate and ping-pang effect.

SAE-TOPSIS algorithm for vertical handoff decision in heterogeneous wireless networks

An improved technique for order preference by similarity to ideal solution （TOPSIS） algorithm, SAE-TOPSIS, is proposed for the vertical handoff decision in heterogeneous wireless networks. The signal to interference plus noise ratio （SINR） effects, analytic hierarchy process （AHP） and infor- mation entropy （SAE） weight method were introduced into the algorithm. Handoff decision meeting the multi-attribute quality of service （QoS） requirement is made according to an attribute matrix and weight vector using the TOPSIS algorithm. The simulation results have shown that the proposed algo- rithm can provide satisfactory performance fitted to the characteristics of the traffic.

An improved multiplicative exponent weighting vertical handoff algorithm for WLAN/WCDMA heterogeneous wireless networks

An improved MEW （ muhiplicative exponent weighting） algorithm, SLE-MEW is proposed for vertical handoff decision in heterogeneous wireless networks. It introduces the SINR（ signal to interference plus noise ratio） effects, LS （least square） and information entropy method into the algorithm. An attribute matrix is constructed considering the SINR in the source network and the equivalent SINR in the target network, the required bandwidth, the traffic cost and the available bandwidth of participating access networks. Handoff decision meeting multi-attribute QoS（quality of serv- ice） requirement is made according to the traffic features. The subjective weight relation of decision elements is determined with LS method. The information entropy method is employed to derive the objective weights of the evaluation criteria, and lead to the comprehensive weight. Finally decision is made using MEW algorithm based on the attribute matrix and weight vector. Four 3GPP（ the 3rd generation partnership project） defined traffic classes are considered in performance evaluation. The simulation results have shown that the proposed algorithm can provide satisfactory performance fitting to the characteristics of the traffic.