异构无线接入网络中的通用链路层技术

如何实现异构环境下的多种无线接入网络融合以及多种无线接入技术之间的协同工作,是未来移动通信研究的主要内容。通用链路层(GLL)基于可重配置的链路层平台,完成不同无线接入技术的协同工作,从而实现了无缝和无损的垂直切换。通用链路层作为解决异构网络协同工作的一种新型技术,已经引起了相关研究领域的广泛关注。通用链路层可以划分为通用和特殊功能部分,并且在垂直切换中具有一套独特的执行过程。相比其他异构接入方案,通用链路层在切换执行的性能方面具有优势。     

Enhancing Fairness and Throughput of TCP in Heterogeneous Wireless Access Networks

Most of the recent research on TCP over heterogeneous wireless networks has concentrated on differentiating between packet drops caused by congestion and link errors, to avoid significant throughput degradations due to the TCP sending window being frequently shut down, in response to packet losses caused not by congestion but by transmission errors over wireless links. However, TCP also exhibits inherent unfairness toward connections with long round-trip times or traversing multiple congested routers. This problem is aggravated by the difference of bit-error rates between wired and wireless links in heterogeneous wireless networks. In this paper, we apply the TCP Bandwidth Allocation (TBA) algorithm, which we have proposed previously, to improve TCP fairness over heterogeneous wireless networks with combined wireless and wireline links. To inform the sender when congestion occurs, we propose to apply Wireless Explicit Congestion Notification (WECN). By controlling the TCP window behavior with TBA and WECN, congestion control and error-loss recovery are effectively separated. Further enhancement is also incorporated to smooth traffic bursts. Simulation results show that not only can the combined TBA and WECN mechanism improve TCP fairness, but it can maintain good throughput performance in the presence of wireless losses as well. A salient feature of TBA is that its main functions are implemented in the access node, thus simplifying the sender-side implementation.     

异构无线网络可信接入设计及实现

异构无线网络互连后的安全问题是当前网络安全研究的一个热点问题,为了解决异构网络互连后产生的接入安全问题,提出了一种基于信任模型的可信接入框架,该框架建立了异构无线网络间的信任评价体系,对接入异构无线网络用户除了进行身份验证,还必须进行用户信任度的验证,既拒绝了恶意节点接入,又确保了合法节点的安全接入,从而保证异构无线网络互连接入的安全和可信。     

基于混沌遗传的异构无线网络接入选择策略

为了解决异构无线网络接入选择问题,提出一种基于混沌遗传算法的解决方法.将网络接入选择转换为一个多属性优化问题,利用混沌遗传算法解决全局寻优问题.算法首先通过超混沌系统产生初始种群和混沌扰动向量,对遗传算法进行改进;然后利用混沌遗传算法对适应度函数求解得到网络选择评价指标权重.仿真结果表明,该算法能够使新到达的用户更均匀地分布在各备选网络中,有效降低网络阻塞率并减小各候选网络阻塞率差距,实现网络的负载均衡.     

异构无线网络多链路接入动态资源分配算法

异构无线网络(Heterogeneous Wireless Networks, HWNs)环境下现有接入控制算法的主要问题是通过单一的传输链路建立移动用户和无线网络之间的连接,并且接入过程中的资源分配没有对全网的传输性能进行优化。为了解决上述问题,该文分析了HWNs中的资源分配模型和链路接入速率模型,提出一种支持多链路接入的动态资源分配算法MLA-DRA。算法以最大化系统传输速率为目标,将用户接入过程转化为前后相互联系的多阶段决策过程,利用前一阶段用户的资源分配状态计算下一阶段用户的最优解,从而推导出系统传输速率的最优值。在仿真平台上对MLA-DRA算法进行了性能分析,并且和其它算法进行了性能比较,实验结果表明,MLA-DRA算法能有效利用系统资源以及提高系统传输速率。     

无线接入网综述

1 接入网与无线接入网 整个通信网分为两部分:核心网(市话端局以上部分)与接入网(市话端局或远端模块以下的网络部分)。 接入网是指从本地交换局到用户之间的信息传送网。通信业务的发展对接入网提出了数字化、宽带化、灵活、可靠、易于管理等要求,希望一条用户线可     

异构无线网络业务接入多目标优化控制算法

提出了一种应用于异构无线网络环境的基于多目标优化的业务接入控制算法.该算法以业务占用总资源最少、业务阻塞率最低和网络间负载最均衡为目标建立了多目标优化控制模型,采用高斯和戒上型组合隶属函数将多目标问题模糊化,利用最大化满意度指标法将多目标问题转化为单目标问题,并通过遗传算法求得最优解.仿真结果表明,所提算法能在兼顾各网络资源高效利用的同时,保证业务接入的可靠性,并相对于参考算法有效降低了业务阻塞率.     

Improved Resource Management through User Aggregation in Heterogeneous Multiple Access Wireless Networks

In this letter we discuss the exploitation of aggregated mobility patterns in mobile networks including heterogeneous multiple access techniques. We advocate the use of knowledge about neighboring devices to create routing groups (RGs) of adjacent nodes in order to optimize radio resource management. Basically, RGs consist of aggregated logical structures which are built and maintained at the application layer. Their use allows decreased signaling overhead between groups of nodes and access points (AP) and, at the same time, improved connectivity, which is achieved through the exploitation of technology diversity and relaying schemes. We illustrate a simple yet effective analytical model, and validate it through accurate simulation results. Finally, we show the effectiveness of the RG approach in terms of resource efficiency, throughput and multiple access performance.     

基于蚁群算法的模糊神经网络垂直切换算法

提出了基于蚁群算法(ACO)优化的模糊神经网络垂直切换算法ACO-FNN,综合考虑了信号强度、移动速度、可用带宽等因素进行模糊神经网络处理,并采用蚁群算法进行优化,调整隶属度函数的参数。仿真结果表明,该算法能够在减少乒乓效应的基础上更好的保证用户的服务质量QOS。     

Location-Aided Handover in Heterogeneous Wireless Networks

The concept of being always online, regardless of the time and place, has been one of the hot topics in the commercial and scientific forums during the last years. The term itself is not solidly defined, however it is often used to refer to user's ability to get the same services via changing variety of underlying networks. In order to really work, this kind of multiaccess in heterogeneous networks still requires research, technological achievements and even compromises. The key to successfully implement the multiaccess is vertical handover that allows the application services to be seamlessly transferred between different networks.     

接入网发展中的相关热点问题分析

本文从电信企业建设发展的角度,分析了当前接入网建设所关注的热点问题如接入网一模块局、ＩＰ接入、ＨＦＣ、接入网网管建设,接入网与“九七工程”、接入网建设中提了后几百米等进行了分析,同时结合相关技术要求,提出了相应的发展策略。     

A Network Selection Algorithm Based on Enhanced Access Router Discovery in Heterogeneous Wireless Networks

The management process between different wireless technologies for mobile devices is very important to complete the handover operations. The handover operation needs to determine the delay and packet loss in order to be the quality of service within a certain level. Selecting the best available network at the appropriate time is very significant in the direction of realizing ubiquitous networks. In this paper a network selection approach named enhanced access router discovery (EARD) is proposed. The approach is developed to work in a heterogeneous environment including of WiMAX and WLAN networks. The EARD method utilizes the prioritized rating for multiple criteria (PRMC) proposed for selecting the target network. The proposed approach is evaluated with respect to various conditions with different traffic types. The simulation results show that our proposed approach outperform the traditional network selection methods is selecting the most appropriate network.     

Inter Radio Access Technology [IRAT] Handover Algorithms for Heterogeneous Wireless Networks

Wireless Personal Communications - Inter-system handover is important for 4G/5G networks as these heterogeneous wireless networks (HWNs) have integrated different radio access technologies with...     

基于加权协商对策论异构网络快速无线传输的速率分配算法

本文研究异构无线网络合作传输的速率分配问题.作为合作传输的理性参与者,异构网络可通过反复协商得到彼此都满意的最优分配方案,即协商对策.因此,本文在速率需求和可用带宽这两个约束条件下,考虑网络传输能力的异构性,用加权协商对策论对异构网络合作传输的速率分配进行了数学建模;以最小传输时间作为优化目标构造了效用函数,证明了该函数是一个凸函数,并利用拉格朗日乘数法推导出最优显式解;提出了一种在终端上可实现的速率分配算法,进行了性能仿真实验.本文算法特别适合于应急通信等快速传输场景.     

宽带技术与应用讲座第二讲宽带无线接入技术及其展望

本文介绍了各种(宽带)无线接入技术,并分别讨论了他们的优缺点,对现有无线宽带接入技术作了概括,并对宽带无线接入技术的未来进行了展望和预测。     

Heterogeneous Wireless Networks: Configuration and Vertical Handoff Management

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     

A Noncooperative Game-Theoretic Framework for Radio Resource Management in 4G Heterogeneous Wireless Access Networks

Fourth generation (4G) wireless networks will provide high-bandwidth connectivity with quality-of-service (QoS) support to mobile users in a seamless manner. In such a scenario, a mobile user will be able to connect to different wireless access networks such as a wireless metropolitan area network (WMAN), a cellular network, and a wireless local area network (WLAN) simultaneously. We present a game-theoretic framework for radio resource management (that is, bandwidth allocation and admission control) in such a heterogeneous wireless access environment. First, a noncooperative game is used to obtain the bandwidth allocations to a service area from the different access networks available in that service area (on a long-term basis). The Nash equilibrium for this game gives the optimal allocation which maximizes the utilities of all the connections in the network (that is, in all of the service areas). Second, based on the obtained bandwidth allocation, to prioritize vertical and horizontal handoff connections over new connections, a bargaining game is formulated to obtain the capacity reservation thresholds so that the connection-level QoS requirements can be satisfied for the different types of connections (on a long-term basis). Third, we formulate a noncooperative game to obtain the amount of bandwidth allocated to an arriving connection (in a service area) by the different access networks (on a short-term basis). Based on the allocated bandwidth and the capacity reservation thresholds, an admission control is used to limit the number of ongoing connections so that the QoS performances are maintained at the target level for the different types of connections.     

Terminal-Controlled Mobility Management in Heterogeneous Wireless Networks

The coexistence of multiple access technologies deployed by different operators is fundamental for future fourth-generation mobile networks. In spite of this heterogeneity, seamless interoperator/intersystem mobility is a mandatory requirement. In this article we present a seamless mobility management approach that does not require changes to existing network infrastructure. The novelty of the proposed approach is that mobility management is fully controlled by the terminal, and network selection is user-centric, power-saving, cost-aware, and performance-aware. Total mobility management, including interface management, handover decision, and execution, is also detailed