认知无线网络基础理论与关键技术研究

认知无线网络是一种具有认知过程的网络,通过网络环境的学习分析,对网络状态进行规划、决策和响应。认知无线网络是解决网络容量受限问题的有效途径之一,满足了国家对频谱高效利用和异构网络融合的战略需求,作为5G关键技术为未来无线通信网络的发展指明方向。主要介绍认知无线网络的体系架构、研究的基础理论和实现的关键技术,最后给出认知无线网络的验证演示平台。     

认知融合网络的关键技术

关注异构蜂窝网络和认知无线网络的发展,分别总结了认知异构蜂窝网络、认知家庭基站和认知WiFi 2.0网络的概念和相应研究,凝练了认知融合网络的概念。针对认知融合网络中宏站与多小站共存于相同频段,必然导致严重的干扰问题,提出了认知资源管理和认知干扰管理环路框架,实现资源和干扰的高效管理,有效提升端到端的用户体验质量。最后展望了认知融合网络的未来发展方向和关键技术问题。     

基于认知的重配置无线网络技术

端到端重配置技术旨在解决异构无线网络融合和无线资源的最优化利用,随着重配置技术研究的发展和认知理论研究的不断深入,使得未来具有认知能力的重配置无线网络的实现成为可能。目前,对端到端重配置技术的研究包括重配置无线网络体系结构及实现向重配置无线网络的演进过程中的关键技术。     

异构多模终端的接入选择功能架构

不同类型无线网络的融合是宽带无线通信发展的必然趋势。在异构融合网络环境中,无论何种无线网络都能够提供无所不在的最优服务。具有挑战性的问题就是异构多模终端的管理系统和接入选择功能架构的设计。一种异构多模终端管理架构通过与各协议层的有效交互,可以适应多种接入标准与技术的要求,实现多模异构终端的无缝接入和移动。接入选择是核心研究问题之一,接入选择功能架构主要包含3个模块：接入适配、移动管理、用户偏好。     

认知网络体系架构及相关技术

应用多样化和复杂的网络结构使当前网络系统缺乏智能的自适应能力。认知网络正是应这种实际需求而产生的,它被认为是提高网络端到端性能、简化网络管理和提高网络自适应性的新途径。文章从认知网络体系架构和相关技术出发,分别对认知网络体系架构动态发展、环境感知、数据融合、知识表示和推理、智能决策相关的知识概念与技术进行分析与总结。     

分层异构无线网络的协议架构和关键技术

分层异构无线网络技术因其可以有效提高网络频谱效率、满足不同热点覆盖需求、大幅提升系统容量等优点,而成为当今LTE-Advanced系统中的关键技术之一.总结了分层异构无线网络的背景、定义以及架构,并重点讨论了由于传统网络拓扑结构的改变而引发的干扰问题,详述了3GPP标准中的增强干扰协调方案,最后分析了分层异构无线网络中的其他关键技术,如网络自组织、回程链路设计、小区选择和切换、节能、认知无线电技术等.这些关键技术对于分层异构无线网络商用化部署具有指导意义.     

认知网络与网络融合

分析了在无线技术快速发展背景下异构网络融合的特点和技术要求,阐释了认知网络概念及其“目标-认知决策-重配置”三层次网络结构模型,描述了作为认知网络基础的上下文感知、跨层设计和重配置三个关键技术,最后讨论认知网络在异构网络融合中的应用前景。     

一种基于云计算的异构无线网络资源管理架构

网络资源管理是构建异构无线网络的关键技术之一。文章阐述异构网络资源管理的研究背景和相关研究工作。针对分布式资源管理架构存在的问题,提出一种基于云计算平台的分布式异构无线网络资源管理架构,说明此框架下的网络选择及资源分配流程。探讨异构无线网络融合架构系统模型设计,包括云计算平台和终端模型的设计。     

基于贝叶斯网络的认知网络推理方法

文章阐述了认知网络的控制架构,并在此架构上建立了基于贝叶斯网络的认知网络推理模型,通过此推理模型预测出网络的性能参数,为认知网络的自主决策提供依据,使得认知网络能在网络环境变化时自适应地做出反应,从而真正实现端到端的QoS（服务质量）目标。     

认知无线网络中拓扑重构的研究

随着异构网络融合和网络自适应化逐渐成为必然的发展趋势,认知无线网络随之出现,并提供了一种实现全局端到端目标优化的方法。认知无线网络由能自适应改变自身配置的网络设备组合而成,为设计灵活高效的拓扑策略提供了可能性和保障。提出了一种拓扑重构的控制策略,能够规划数据传输路由,在高效利用空闲频谱资源的同时,提升了传输的效率和性能。     

Trusted cognitive radio networking

Networking cognitive radios and nodes from primary system (PS) results in a heterogeneous coexisting multi‐radio wireless network, so that significant network throughput gain can be achieved. However, by investigating cognitive radio network (CRN) architecture, the links in CRNs are unlikely to support complete security check due to link dynamics, opportunistic availability, and uni‐directional in available time window. We therefore introduce trusted cognitive radio networking (TCRN) concept to facilitate network functions such as association in dynamic spectrum access and routing. First of all, we explore the mathematical framework for trust in CRNs. We then show successful association of node to CRN based on the mathematical structure of trust from statistical decision theory. Furthermore, we modify the machine‐learning algorithm to update the trust measure for each node, and develop rules of thumbs to facilitate TCRN with learning capability, based on numerical simulations. Trusted CRN can greatly alleviate heterogeneous challenge for CRN operation. Copyright © 2009 John Wiley & Sons, Ltd.     

Reconfiguration Decision Making Based on Ant Colony Optimization in Cognitive Radio Network

Facing to the challenges of dynamic adaptation capabilities in the time-varying environment of cognitive radio networks (CRN), reconfiguration capabilities are introduced to flexibly and dynamically adapt to changing wireless environment and service requirement. As one of the essential characteristics for CRN, the cognitive reconfiguration can meet the user requirements, realize interoperability between heterogeneous networks, make full use of radio resources and adapt to the time-varying environment to achieve the end-to-end requirements. However, the reconfiguration implementation is still challenging due to its need for complex environment cognition and multi-objects optimization. In this direction, ant colony optimization(ACO) technique, as an intelligent technology to solve the complex issues, is introduced to the appropriate model of the reconfiguration decision making process to achieve the adaption alternatives. The aim of this paper is to present a generic cognitive reconfiguration framework including indispensable function entities for autonomous reconfiguration decision making with regard to the multiple and complex objectives. Moreover, three kinds of reconfiguration approaches, which are parameters reconfiguration, radio resource reconfiguration and heterogeneous access reconfiguration, are proposed. Finally, numerous results prove the effective performance improvements of ACO based reconfiguration solution in CRN.     

Ambient Networks项目及其关键技术

随着无线通信技术的不断发展，多接入技术、不同运营商和多样化终端共存的局面使得传统的无线通信格局面临困境，异构网络融合成为未来网络发展的必然趋势。欧盟项目Ambient Networks对异构网络融合进行了深入的研究。Ambient Networks提出了Ambient控制平面（ACS）来支持动态的、分布式的、自管理和自维护的异构网络管理；通过多无线接入结构（MRA）充分利用多种接入技术并存带来的优势，为用户提供总是处于最佳连接的服务。     

基于生存系统模型的认知无线电网络频谱管理自治系统设计

针对动态频谱接入和认知无线电技术对频谱管理的新要求,采用分层的频谱管理理念,基于生存系统模型(Viable System Model,VSM)设计适合认知无线电网络的频谱管理自治系统,该系统通过节点参与频谱管理,网络自我约束等措施,实现认知无线电网络对频谱的自治。最后,将该系统应用于一种异构网络共存的频管案例设计中,仿真分析表明:本文提出的基于VSM的频谱管理自治系统响应时间大幅度降低;认证效率为O(1),较传统方式性能有很大提升。     

MIRAI architecture for heterogeneous network

One of the keywords that describe next-generation wireless communications is "seamless." As part of the e-Japan Plan promoted by the Japanese Government, the Multimedia Integrated Network by Radio Access Innovation project has as its goal the development of new technologies to enable seamless integration of various wireless access systems for practical use by 2005. This article describes a heterogeneous network architecture including a common tool, a common platform, and a common access. In particular, software-defined radio technologies are used to develop a multiservice user terminal to access different wireless networks. The common platform for various wireless networks is based on a wireless-supporting IPv6 network. A basic access network, separated from other wireless access networks, is used as a means for wireless system discovery, signaling, and paging. A proof-of-concept experimental demonstration system is available     

无线数字家庭网络泛在接入技术

数字家庭网络是通信领域的一个重要分支，近年来发展非常迅速。基于电信网络的数字家庭网络体系结构在中国已经标准化，但就接入方式而言，只是定义了可以使用无线方式，如何组建无线数字家庭网络是未来研究的重点。文章提出了无线数字家庭网络泛在接入概念，给出了无线泛在接入网络体系结构，并就其中的关键技术进行了探讨，包括感知无线电、无线网状网（Mesh）网络理论、通用接入点链路转换机制、业务的QoS保障机制以及电磁兼容和异构系统共存机制等。     

A survey on spectrum management in cognitive radio networks [cognitive radio communications and networks]

Cognitive radio networks will provide high bandwidth to mobile users via heterogeneous wireless architectures and dynamic spectrum access techniques. However, CR networks impose challenges due to the fluctuating nature of the available spectrum, as well as the diverse QoS requirements of various applications. Spectrum management functions can address these challenges for the realization of this new network paradigm. To provide a better understanding of CR networks, this article presents recent developments and open research issues in spectrum management in CR networks. More specifically, the discussion is focused on the development of CR networks that require no modification of existing networks. First, a brief overview of cognitive radio and the CR network architecture is provided. Then four main challenges of spectrum management are discussed: spectrum sensing, spectrum decision, spectrum sharing, and spectrum mobility.     

Resource allocation in heterogeneous cooperative cognitive radio networks

In cognitive radio networks (CRNs), resources available for use are usually very limited. This is generally because of the tight constraints by which the CRN operate. Of all the constraints, the most critical one is the level of permissible interference to the primary users. Attempts to mitigate the limiting effects of this constraint, thus achieving higher productivity, are a current research focus, and in this work cooperative diversity is investigated as a promising solution. Cooperative diversity has the capability to achieve diversity gain for wireless networks. In the work, therefore, the possibility of and mechanism for achieving greater utility for the CRN when cooperative diversity is incorporated are studied. To accomplish this, a resource allocation model is developed and analyzed for the heterogeneous, cooperative CRN. In the model, during cooperation, a best relay is selected to assist the secondary users that have poor channel conditions. Overall, the cooperation makes it feasible for virtually all the secondary users to improve their transmission rates while still causing minimal harm to the primary users. The results show a marked improvement in the resource allocation performance of the CRN when cooperation is used in contrast to when the CRN operates only by direct communication.     

Radio Network Aggregation for 5G Mobile Terminals in Heterogeneous Wireless and Mobile Networks

This paper provides a novel design concept for advanced mobile multi interface terminals with radio network aggregation capability and enhanced quality of service (QoS) provisioning for multimedia services (voice, video and data) in heterogeneous wireless and mobile networks. A new module is established which provides the best QoS and lowest cost for any given multimedia service by using simultaneously all available wireless and mobile access networks for a given traffic flow. This novel adaptive QoS module with adaptive QoS routing algorithm is called advanced QoS routing algorithm (AQoSRA), which is defined independently from any existing and future radio access technology. The performance of our proposal is evaluated using simulations and analysis with multi-interface mobile stations with AQoSRA within, carrying multimedia traffic in heterogeneous mobile and wireless environment with coexistence of multiple Radio Access Technologies, such as 3G, 4G as well as future 5G radio access networks. The analysis of the proposed framework for radio networks aggregation in advanced mobile terminals has shown overall better performances regarding the achievable throughput and multimedia access probability in heterogeneous wireless and mobile environment.     

基于簇的分布式认知无线电网络安全体系结构

针对认知无线电网络中出现的模仿主用户攻击和自私行为攻击问题,提出一种基于簇的分布式认知无线电网络安全体系结构.这种安全体系结构通过采用数据加密和认证等安全技术解决无线网络中原有的安全问题,通过在主用户基站与认知用户间使用Hash匹配技术可解决模仿主用户攻击问题,通过簇头向目的节点发送转发节点的可用频谱信息可解决自私行为攻击问题.由分析可知该安全体系结构是安全、高效和可行的.