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认知无线电技术通过感知频谱后进行动态频谱资源分配,极大地提高了频谱利用效率。频谱感知是实现认知无线电技术的前提和基础,文中针对频谱感知技术中单节点检测的局限性对能够改善频谱感知能力的协作感知技术进行了分析及讨论,重点分析了基于能量检测法的协作感知中的各种数据融合算法,并在此基础上提出了目前协作感知中存在的问题及未来的研究方向。 相似文献
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基于认知无线电通信系统的核心技术频谱感知经典算法,详细阐述各个算法模型设计原理及实现机制。最后,对频谱感知技术经典算法的优缺点进行了比较,并对频谱感知技术的未来研究趋势进行了展望。 相似文献
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在日益复杂的电磁频谱环境中,精准获取完备的频谱态势信息是做出准确频谱决策的重要前提。首先,介绍了频谱测绘并对比了其与频谱感知的主要区别。接着,综述了现有频谱态势生成方法的研究现状。然后,提出了异构性、大尺度缺失、动态性、环境复杂性等挑战下的多维频谱态势压缩测绘技术研究工作,有效弥补了传统频谱态势生成方法忽略频谱态势感知过程而导致的频谱测绘框架不完整性,该研究可进一步为提升频谱利用效率、增强频谱安全维护以及强化军事电磁对抗的决策提供更精准的指导。最后,对未来频谱压缩测绘的发展趋势进行了展望。 相似文献
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感知无线电接收机为了感知其周围的无线电环境,首要的工作就是对其周围存在的信号进行检测。本文针对感知无线电系统中最为关键的频谱空穴检测技术进行了研究。通过对3种信号检测技术的比较,选择循环平稳特征检测法作为感知无线频谱的方法并对该方法进行了仿真。此外.对控制实体根据频谱感知的结果、从频谱中检测出频谱空穴区域的功能、以及感知无线电接收机与感知无线电发射机进行协调的功能也进行了仿真。 相似文献
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Cognitive Radio is an emerging technology to accommodate the growing demand for wireless technology via dynamic spectrum access to enhance spectrum efficiency. Spectrum handoff is an important component of Cognitive Radio technology for practical implementation of radio frequency access strategy and better utilization of spectrum in both primary and secondary networks. The probability of spectrum handoff and expected number of spectrum handoffs are key parameters in performance analysis and design of the cognitive radio network. This work presents an analytical model to evaluate the impact of secondary users’ mobility on intra-cell spectrum handoff considering primary users’ activity model in a cognitive radio network. A standard form of intra-cell spectrum handoff probability and expected number of intra-cell spectrum handoffs are derived for complete call duration of a non-stationary secondary user. The probability and expected number of intra-cell spectrum handoffs of a post inter-cell handoff call are also derived for generalized residual time distributions of call holding time and spectrum holes. A detailed analysis of these performance measuring metrics is presented under the impact of departure rate and cell crossing rate of secondary users. The accuracy of the derived analytical result is validated by Monte-Carlo simulation of the model. 相似文献
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尹奕江 《电信工程技术与标准化》2018,(11)
变频的目的是为了使信号能够在特定的信道内利用合适的频率对信号进行有效传输,是无线通信系统中需要经常涉及到的问题。频谱反转一般是在传输过程中由于变频而造成的接收端所收与发射端所发的信号频谱相反的现象。本文对频谱反转产生的原因以及如何在基带系统中处理的方法进行了分析和介绍。 相似文献
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该文提出了一种分布式多输入多输出正交频分复用(MIMO-OFDM)系统初始信号检测和同步捕获算法。该算法设计了导频符号,采用谱分析方法实现可靠的初始信号检测、粗定时和粗频偏估计,并在快速傅里叶变换(FFT)之后进行精确地频偏和定时估计。仿真结果表明,该算法在低信噪比多径瑞利信道条件下具有很好的性能。 相似文献
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认知无线电技术是解决无线资源紧缺的有效方法.基于非协作感知的不确定性,协作频谱感知方法具有更高的准确度,因此被人们所关注.文中提出了一种利用协作式能量检测的方法,通过利用近似计算将检测时间缩短,提高检测效率.经仿真结果证实,该方法能有效提高检测结果的准确性. 相似文献
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认知无线电(Cognitive Radio)是能够高效利用无线频谱资源和显著提高通信性能的智能无线通信技术,对于无线通信的发展具有积极作用和深远影响。本文首先介绍了认知无线电的提出背景、幕本概念和技术特点。其次,说明了认知无线电的工作机理并详细探讨了涉及的关键技术。最后,概述了认知无线电的标准化进展并展望了今后的工作。 相似文献
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无线多媒体传感器网络(WMSNs)具有实时监控,收集和处理多媒体信息的功能,有广泛的应用前景。较之传统无线传感器网络,WMSNs无线传输多媒体信息需要更大带宽。然而,随着无线通信设备的广泛应用,有限的可用频谱资源日益匮乏。利用动态频谱分配技术,可以扩展WMSNs的通信频段,增强抗干扰能力。考虑到WMSNs节点的物理限制,如计算能力和能量供应,该文提出了适合WMSNs的频谱感知方法和频谱管理方法。频谱感知采用各节点的轮换机制感知整个频段;频谱管理可以确保对授权用户影响最小的信道被首先使用。WMSNs使用上述方法可以感知周围无线电环境,利用空闲私有频段进行无线通信。最后,通过实验证明了该文提出的动态频谱分配技术对WMSNs的有效性。 相似文献
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将CDMA2000作为无线频谱移动监测系统中数据传输的通道,为无线频谱移动监测系统提供实时的数据,它使得无线频谱移动监测系统更为方便和快捷地对系统内的各种资源进行管理 相似文献
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《电子学报:英文版》2016,(5):928-935
The last decade has witnessed a rapid growth in wireless communications technology,and as a result the demand for spectrum resources increased rapidly.Unfortunately,many new wireless demanders cannot access the limited wireless licenses in time while large chunks of spectrum are idle.To solve this,we design a multiunit double auction mechanism for heterogeneous spectrum channels,which take the spatial and temporal reuse into consideration.The proposed scheme first introduces the multi-participants multi-heterogeneous-spectrum trading double auction to illustrate the system model.Some techniques such as spectrum categorize,virtual sellers and buyers' conflict graph construction,and reconstruction of buyer groups are adopted to achieve a high efficiency of the algorithm.Then,we also prove the truthfulness,individual rationality,and budget balance of the proposed scheme.Finally,the simulation results show that the practical performance of the proposed scheme can efficiently improve the spectrum transaction ratio,reuse ratio,and the buyer's satisfactory ratio. 相似文献
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《Digital Communications & Networks》2016,2(1):47-56
Recently, wireless distributed computing (WDC) concept has emerged promising manifolds improvements to current wireless technologies. Despite the various expected benefits of this concept, significant drawbacks were addressed in the open literature. One of WDC key challenges is the impact of wireless channel quality on the load of distributed computations. Therefore, this research investigates the wireless channel impact on WDC performance when the latter is applied to spectrum sensing in cognitive radio (CR) technology. However, a trade-off is found between accuracy and computational complexity in spectrum sensing approaches. Increasing these approaches accuracy is accompanied by an increase in computational complexity. This results in greater power consumption and processing time. A novel WDC scheme for cyclostationary feature detection spectrum sensing approach is proposed in this paper and thoroughly investigated. The benefits of the proposed scheme are firstly presented. Then, the impact of the wireless channel of the proposed scheme is addressed considering two scenarios. In the first scenario, workload matrices are distributed over the wireless channel. Then, a fusion center combines these matrices in order to make a decision. Meanwhile, in the second scenario, local decisions are made by CRs, then, only a binary flag is sent to the fusion center. 相似文献