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Interference Mitigation MAC Protocol for Cognitive Radio Networks
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作者 Nasir Faruk Maaruf Ali Mohammed Ibrahim Gumel 《Wireless Engineering and Technology》 2012年第2期63-71,共9页
The growing demand for wireless services coupled with the limited availability of suitable electromagnetic spectrum is increasing the need for more efficient RF spectrum utilization. Spectrum allocated to TV operators... The growing demand for wireless services coupled with the limited availability of suitable electromagnetic spectrum is increasing the need for more efficient RF spectrum utilization. Spectrum allocated to TV operators can potentially be shared by wireless data services, either when the primary service is switched off or by exploiting spatial reuse opportunities. This paper describes a dynamic spectrum access scheme for use in the TV bands which uses cognitive radio techniques to determine the spectrum availability. The approach allows secondary users (SU) to operate in the presence of the primary users (PU) and the OPNET simulation and modelling software has been used to model the performance of the scheme. An analysis of the results shows that the proposed scheme protects the primary users from harmful interference from the secondary users. In comparison with the 802.11 MAC protocol, the scheme improves spectrum utilization by about 27% while limiting the interference imposed on the primary receiver. 展开更多
关键词 dynamic spectrum access (DSA) Optimized Network Engineering Tool (OPNET) TV WHITE Space COGNITIVE Radio Networks Signal-to-interference Ratio (SIR)
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Performance Analysis of Wireless Network with Opportunistic Spectrum Sharing via Cognitive Radio Nodes
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作者 R. Kaniezhil C. Chandrasekar 《Journal of Electronic Science and Technology》 CAS 2012年第4期342-351,共10页
Cognitive radio (CR) is found to be an emerging key for efficient spectrum utilization. In this paper, spectrum sharing among service providers with the help of cognitive radio has been investigated. The technique o... Cognitive radio (CR) is found to be an emerging key for efficient spectrum utilization. In this paper, spectrum sharing among service providers with the help of cognitive radio has been investigated. The technique of spectrum sharing among service providers to share the licensed spectrum of licensed service providers in a dynamic manner is considered. The performance of the wireless network with opportunistic spectrum sharing techniques is analyzed. Thus, the spectral utilization and efficiency of sensing is increased, the interference is minimized, and the call blockage is reduced. 展开更多
关键词 Call blocking access cognitive radio dynamic spectrum interference spectrum sharing.
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认知网络中主用户接收机通信区域建模及分析
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作者 廖勇 谭晓衡 +4 位作者 程金波 张宇翔 杨宏 丰建军 陈徐洪 《应用科学学报》 EI CAS CSCD 北大核心 2012年第2期116-119,共4页
在现有认知无线网络模型综合分析的基础上,针对以主用户发射机为中心进行干扰区域建模的不足,提出一种基于主用户接收机为中心的认知网络模型.基于该模型,采用信息论的观点,在主用户最低吞吐量和主用户通信中断概率的限制条件下,分析得... 在现有认知无线网络模型综合分析的基础上,针对以主用户发射机为中心进行干扰区域建模的不足,提出一种基于主用户接收机为中心的认知网络模型.基于该模型,采用信息论的观点,在主用户最低吞吐量和主用户通信中断概率的限制条件下,分析得出了主用户通信半径、认知用户密度及主用户吞吐量的相互量化制约关系.数值分析结果验证了该模型在认知用户对主用户接收机干扰过程中的合理性和有效性. 展开更多
关键词 认知无线电 动态频谱接入 服务质量 信道干扰 通信半径
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基于干扰门限的动态频谱接入及性能分析
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作者 胡晗 朱琦 《南京邮电大学学报(自然科学版)》 2010年第2期8-15,共8页
如何在不干扰授权用户(主用户)正常通信的情况下提高次用户使用频谱的效率,这是认知无线电系统中需要解决的关键问题。在主用户优先的基础上,提出了基于干扰门限的动态频谱接入系统的M arkov频谱占用模型,并基于该模型对动态频谱接入过... 如何在不干扰授权用户(主用户)正常通信的情况下提高次用户使用频谱的效率,这是认知无线电系统中需要解决的关键问题。在主用户优先的基础上,提出了基于干扰门限的动态频谱接入系统的M arkov频谱占用模型,并基于该模型对动态频谱接入过程进行了分析。为了进一步降低次用户间的相互干扰,通过对次用户接入概率的设计,以协调各类次用户间的频谱接入。在3种优化准则下,对次用户依据概率接入的基于干扰门限的主用户优先的动态频谱接入系统进行了仿真。仿真结果表明,基于干扰门限的主用户优先的动态频谱接入系统能大大提高次用户的接入机会,最大程度地提高了次用户的吞吐量。在比例公平准则下次用户接入的性能,与最大化吞吐量准则相比体现了更好的公平性,与最大化最小准则相比能够获得更大的吞吐量,因此基于比例公平准则可以使得系统在高效性和公平性间得到很好的均衡。 展开更多
关键词 认知无线电 动态频谱接入 马尔可夫模型 干扰门限
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认知无线网络信道接入协议 被引量:5
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作者 阚保强 范建华 王建业 《软件学报》 EI CSCD 北大核心 2012年第7期1824-1837,共14页
由于认知无线网络(cognitive radio network,简称CRN)固有"二次利用"的特性,使其日益得到重视.而作为CRN核心构成的MAC(medium access control)协议,业已成为当前各研究机构的一个热点.主要对频谱感测技术、信道接入技术等MA... 由于认知无线网络(cognitive radio network,简称CRN)固有"二次利用"的特性,使其日益得到重视.而作为CRN核心构成的MAC(medium access control)协议,业已成为当前各研究机构的一个热点.主要对频谱感测技术、信道接入技术等MAC层核心设计问题进行了探讨,并针对认知无线网络MAC的特性及需求进行了分析,然后对设计MAC频谱感知技术、信道接入技术、频谱共享技术等相关研究进展进行了归类总结.最后指出了当前面临的主要研究难点及挑战,并提出了一些方向性建议. 展开更多
关键词 认知无线网络 频谱感知 信道接入 动态频谱分配 干扰
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无线网络中需求驱动的动态频谱分配
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作者 王力 易辉跃 +1 位作者 陈斌 胡宏林 《计算机工程》 CAS CSCD 北大核心 2011年第18期115-117,120,共4页
研究无线网络中协同动态频谱接入模型下的动态频谱分配问题,在考虑基站频谱需求的基础上,将物理干扰模型下的动态频谱分配问题建模为一个非线性优化问题。通过将非线性优化问题转换为线性规划问题,提出一种无线网络中需求驱动的动态频... 研究无线网络中协同动态频谱接入模型下的动态频谱分配问题,在考虑基站频谱需求的基础上,将物理干扰模型下的动态频谱分配问题建模为一个非线性优化问题。通过将非线性优化问题转换为线性规划问题,提出一种无线网络中需求驱动的动态频谱分配算法,计算初始频谱分配,并应用迭代增强算法为节点添加多余信道。仿真结果表明,该算法在有效频谱利用率和平均满意度上都优于现有算法。 展开更多
关键词 协同动态频谱接入 物理干扰模型 无线网络 线性规划
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Performance Analysis of Hybrid MAC Protocol for Cognitive Radio Networks
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作者 Nasir Faruk Mohammed I. Gumel +1 位作者 Abdulkarim A. Oloyode Adeseko A. Ayeni 《International Journal of Communications, Network and System Sciences》 2013年第1期18-28,共11页
The rapid growth in demand for broadband wireless services coupled with the recent developmental work on wireless communications technology and the static allocation of the spectrum have led to the artificial scarcity... The rapid growth in demand for broadband wireless services coupled with the recent developmental work on wireless communications technology and the static allocation of the spectrum have led to the artificial scarcity of the radio spectrum. The traditional command and control model (Static allocation) of spectrum allocation policy allows for severe spectrum underutilization. Spectrum allocated to TV operators can potentially be shared by wireless data services, either when the primary service is switched off or by exploiting spatial reuse opportunities. This paper describes a hybrid access scheme based on CSMA/CA and TDMA MAC protocols for use in the TV bands. The approach allows secondary users (SU) to operate in the presence of the primary users (PU) and the OPNET simulation and modelling software has been used to model the performance of the scheme. An analysis of the results shows that, the proposed schemes protect the primary user from harmful Interference from the secondary user. In terms of delay, it was found that packet arrival rates, data rates and the number of secondary users have significant effects on delay. 展开更多
关键词 dynamic spectrum access (DSA) Optimized Network Engineering Tool (OPNET) TV WHITE Space COGNITIVE Radio Networks Signal-To-interference Ratio (SIR) Hybrid MAC
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Guardband Analysis for Distributed OFDMA with User Heterogeneity 被引量:1
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作者 侯炜 张林 +2 位作者 YANG Lei ZHENG Heather 山秀明 《Tsinghua Science and Technology》 SCIE EI CAS 2011年第1期83-89,共7页
This paper presents an in-depth analysis of the interference strength and required guardband width between coexistent users for distributed orthogonal frequency division multiple access (OFDMA). In dynamic spectrum ... This paper presents an in-depth analysis of the interference strength and required guardband width between coexistent users for distributed orthogonal frequency division multiple access (OFDMA). In dynamic spectrum access networks, the cross-band interference between spectrally adjacent users is considered harmful with frequency guardbands inserted between spectrum blocks to eliminate the interference. However, the strength of the cross-band interference depends heavily on the user heterogeneity in different OFDM configurations. The cross-band interference due to the three user heterogeneity artifacts of power heterogeneity, sampling rate heterogeneity, and symbol length heterogeneity is investigated to determine the required guardband width. Analytical and simulation results show that the greater user heterogeneity requires larger guardbands with the sampling rate heterogeneity having the greatest effect. These results can be used to assist the design of spectrum allocation strategies. 展开更多
关键词 distributed orthogonal frequency division multiple access (OFDMA) dynamic spectrum access cross-band interference user heterogeneity
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