认知无线电到软件无线电

认知无线电(Cognitive Radio,CR)技术进一步扩展了软件无线电(SDR)的功能,成为解决频谱资源匮乏问题的有效方法。基于认知无线电在无线通信中的重要作用,介绍了认知无线电的概念,概述了认知无线电在民用和军用领域的应用情况,讨论了认知无线电涉及的关键技术,指出了开展认知无线电技术研究的重要意义。     

认知无线电中的混合认知引擎设计

为了提高认知引擎的性能,更好地实现认知无线电系统参数的智能调整,设计了一 种混合认知引擎,综合运用多种人工智能方法实现认知引擎的推理、学习、优化和决策等功 能。分析了经典认知引擎模型和人工智能在认知引擎中的应用情况,构建了混合认知引擎的 功能结构框图,讨论了混合认知引擎的工作机理和技术特点。分析表明,混合认知引擎 具有较强的灵活性和鲁棒性。     

基于软件无线电思想的数字通信终端接口电路设计与实现

介绍了一种基于软件无线电思想设计的数字通信终端接口电路,分析了主要部分的电路实现和芯片选择,同时介绍了在软件处理中提供宽带带通滤波器和高速ADC、DAC的设计方法和各部分析的具体电路设计。     

从软件无线电到认知无线电的无线通信发展现状

本文归纳了从软件无线电到认知无线电功能的演进。认知无线电又是在软件无线电的基础上提出的智能化的无线通信技术,它着力解决频谱资源的有效利用问题：认知无线电概念的提出将对现行的频谱管理体制提出挑战,并给无线通信带来新的发展空间。在此基础上探讨了认知无线电技术未来发展值得关注的热点问题。     

认知引擎技术

认知无线电（CR）是一种智能的无线电通信系统,其智能主要来自于认知引擎。认知引擎基于软件无线电平台,引入人工智能领域的推理与学习方法,实现认知环路,从而实现CR的感知、自适应与学习能力。认知引擎的要素包括建模系统、知识库、推理机、学习机和各类接口,涉及到知识表示、机器推理和机器学习等关键技术。     

从软件无线电到认知无线电,走向终极无线电——无线通信发展展望

介绍软件无线电三种基本结构及认知无线电基本概念的基础上,提出了基于电子侦察原理的一种新的认知无线电实现架构及其对应的认知循环过程.同时,针对认知无线电存在的问题,提出了基于盲源分离的认知无线电--终极无线电(ultimate radio)的新概念,并对其实现的可行性进行了初步的分析讨论.     

软件无线电数字前端的一种新实现方法

软件无线电（Ｓｏｆｔｗａｒｅ Ｒａｄｉｏ简称ＳＷＲ）是９０提代提出的一种全新的无线通信体系结构，它可使通信系统具有良好的灵活性及可扩展性。为使软件无线电中实现通用无线通信系统，较为理想的情况就是使Ａ／Ｄ和Ｄ／Ａ变换器尽量向射频端靠拢，即完成射频中到中频的下变频后，对整个中频频段作Ａ／Ｄ变换，这之后整个处理都用可编程数字器件以及软件来实现。这样的实现结构将具有非常大的灵活性，可以满足软件无线电的灵活     

认知引擎中案例学习模块的设计与实现

学习能力是认知无线电区别于现有电台的最主要特征,研究基于SOAR架构的案例学习功能在已有认知引擎平台中的设计与实现。首先介绍了人工智能开发工具SOAR的基本原理与概念,进而在认知无线电原型系统平台上,设计并实现了基于SOAR架构的,具备案例学习能力的认知学习模块。具备案例学习能力的认知引擎使认知无线电系统具备从以往经验中获取知识的能力,提高了其在未来任务中的决策性能。     

认知引擎中决策方法的研究

认知无线电(Cognitive Radio,CR)技术通过智能的频谱管理来解决频谱资源"短缺"问题,它能够感知到授权用户的空闲频谱,并有效地加以利用,从而减少与授权用户的冲突。现有无线电参数调整策略无法根据环境变化和用户需求进行智能调整,认知引擎中的决策方法能够解决该问题。遗传算法(Genetic Algorithm,GA)和二进制粒子群算法是实现认知引擎决策的典型算法,在对2种算法进行了介绍之后,仿真比较了2种算法在性能方面的差异。     

认知无线电技术实现和挑战

一些公司和研究机构在认知无线电实现技术上已经做了很多有益的探索。文章介绍了认知无线电技术及认知无线电原型的现状,并且对主要的认知无线电原型进行了比较和分析。然后重点说明基于USRP(通用软件无线电外设)和GNU radio的认知无线电原型的实现方法。最后探讨了认知无线电原型面临的挑战。     

Securing cognitive radio networks

Cognitive radio is a promising technology aiming to improve the utilization of the radio electromagnetic spectrum. A cognitive radio device uses general purpose computer processors that run radio applications software to perform signal processing. The use of this software enables the device to sense and understand its environment and actively change its mode of operation based on its observations. Unfortunately, this solution entails new security challenges. Our objective in this paper is to analyze the security issues of the main recent developments and architectures of cognitive radio networks. We present vulnerabilities inherent to those systems, identify novel types of abuse, classify attacks, and analyze their impact on the operation of cognitive radio‐based systems. Moreover, we discuss and propose security solutions to mitigate such threats. Copyright © 2010 John Wiley & Sons, Ltd.     

Multi‐interface cognitive radio for enhanced routing in multi‐hop cellular networks

Multi‐hop cellular network (MCN) is a wireless communication architecture that combines the benefits of conventional single‐hop cellular networks and multi‐hop ad hoc relaying networks. The route selection in MCN depends on the availability of intermediate nodes and their neighborhood connectivity. Cognitive radio (CR) is an emerging communication paradigm that exploits the available radio frequencies opportunistically for the effective utilization of the radio frequency spectrum. The incorporation of CR and mobile ad hoc network routing protocols in MCN could potentially improve the spectrum utilization and the routing performance of MCN. This paper firstly presents the proposed model for the multi‐interface CR mobile node with transceiver synchronization and then investigates its opportunistic spectrum utilization and routing performance in MCN. Copyright © 2015 John Wiley & Sons, Ltd.     

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.     

一种综合射频系统SCA软件平台的设计与实现

针对机载综合射频开放式系统架构,为了在软件综合层面上实现波形应用软件与具体平台的解耦,设计并实现了一种基于软件通信架构(Software Communication Architecture, SCA)的软件平台及其环境工具,解决了机载平台软件的分布式通信、资源调度管理、系统建模等技术问题,从而实现功能、应用和波形的组件化与动态重构。测试验证与工程应用情况表明,软件平台能够满足机载领域信号、信息处理强实时、高可用的应用需求,可有效提升综合射频系统软件开发质量与集成联试效率。     

An efficient algorithm for backbone construction in cognitive radio networks

Numerous research articles exist for backbone formation in wireless networks; however, they cannot be applied straightforward in cognitive radio network (CRN) due to its peculiar characteristics. Since virtual backbone has many advantages such as reduced routing overhead, dynamic maintenance, and fast convergence speed, we intend to propose a backbone formation protocol in CRN. In this paper, we propose a tree‐based backbone formation protocol along with its maintenance. Our protocol is based on non‐iterative approach, thus leading towards limited message overhead and faster convergence speed. The proposed algorithm first forms the tree by maintaining the parent‐child relationship, and second, the parent nodes are connected together to form the virtual backbone. In the end, we evaluate the performance our protocol through extensive simulations.     

Evolution and future trends of research in cognitive radio: a contemporary survey

The cognitive radio (CR) paradigm for designing next‐generation wireless communications systems is becoming increasingly popular, and different aspects of it are being implemented in currently available wireless systems. In the last decade, a significant amount of research efforts has been made to solve CR challenges, and several standards related to CR and dynamic spectrum access have been developed. Also, there have been advances in software‐defined radio platforms to implement the CR systems. In this article, we provide a comprehensive survey on the evolution of CR research covering aspects such as spectrum sensing, measurements and statistical modeling of spectrum usage, physical layer aspects such as waveform and modulation design, multiple access, resource allocation and power control, cognitive learning, adaptation and self‐configuration, multihop transmission and routing, and robustness and security in CR networks. Also, state‐of‐the‐art research on the economics of CR networks, CR simulation tools, testbeds and hardware prototypes, CR applications, and CR standardization efforts is summarized. Emerging trends on CR research and open research challenges related to the cost‐effective and large‐scale deployment of CR systems are outlined. Copyright © 2013 John Wiley & Sons, Ltd.     

An efficient and adaptive channel handover procedure for cognitive radio networks

In designing cognitive radio systems, one of the most critical issues is handling the channel handover process (CHP). The CHP consists of spectrum sensing, spectrum decision, negotiation on the common control channel, and adjustment of frequency and modulation settings, and such, it can be a time‐consuming process. Consequently, initiating the CHP after each detected user activity (UA) can decrease the aggregate spectrum utilization. To alleviate this problem, we introduce a novel handover strategy to find the optimal trade‐off between the durations of the CHP and UAs. With the use this model, secondary users (SUs) track only local information on their current data channel to make the decision to initiate the CHP or to wait for the termination of the ongoing UA. The system adapts to the dynamic conditions of the data channels and reduces the frequency of handovers to increase throughput and decrease access delay. We give analytical utilization bounds for SUs and also compare the performance of our model to those of other channel handover strategies by using extensive simulations. Our results for channels with heterogeneous loads and dynamic environments show that this model can clearly decrease the frequency of handover and consequently increase the aggregate SU utilization. Copyright © 2013 John Wiley & Sons, Ltd.     

软件无线电在电离层电波探测中的应用

提出了应用软件无线电发展新的电离层电波探测技术，开发新一代电离层电波探测设备的思想，并针对广泛使用的电离层探测设备数字测高仪，详细讨论了软件化数字测高仪的系统结构、特色和可行性。结果表明：发展新的软件化电离层电波探测设备的理论和技术条件均已成熟，它所具有的开放性和灵活性，能更好的满足二十一世纪电离层空间大气研究的需要。     

认知无线电中协作压缩频谱感知算法

针对宽带频谱认知无线电环境中,传统能量检测法在信噪比较低时,容易出现误检而使系统的检测性能下降的问题,文中提出了一种新型高性能的协作频谱感知算法,它是基于压缩理论的多节点频谱感知方法,各节点之间采用基于双判决门限的协作方式。仿真结果显示,双门限协作压缩频谱感知算法在低信噪比的情况下,检测性能明显优于传统能量检测法。     

接收信号处理芯片AD6634及其在软件无线电中的应用

AD6634是Analog Devices公司的四通道宽带可编程数字接收信号处理芯片。文中介绍了AD6634的内部结构和基本功能特点，给出了基于AD6634的通用可编程中频软件无线接收系统的结构，同时给出了系统中AD转换、FIFO和DSP等器件的的选择方向，最后讨论了AD6634主要参数的设置方法。