Description: 认知无线电能有效缓解无线电频谱资源匮乏问题，正交频分复用（OFDM）非常适合认知无线电系统。动态频谱资源分配是认知系统的一项重要功能。本文的目标就是最小化成本函数，这个函数考虑到主用户以及次用户的干扰功率。-Cognitive radio (CR) is a promising concept for improving the utilization of scarce radio spectrum resources. Orthogonal frequency division multiplexing (OFDM) is regarded as a technology which is well-matched for CR systems. Dynamic resource allocation is an important task in such systems. A novel resource allocation algorithm for multiuser OFDM cognitive radio system is presented in this paper. The objective is to minimize a cost function which takes into account the interference
power experienced by the primary user as well as the base station transmit power for secondary users given minimum bit rate requirements for each secondary user. Platform: |
Size: 201728 |
Author:洪波 |
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Description: Cognitive radio frequency spectrum detection-The spectrum sensing of a wideband frequency range is studied by dividing it into multiple subbands.
It is assumed that in each subband either a primary user (PU) is active or absent in a additive white Gaussian
noise environment with an unknown variance. It is also assumed that at least a minimum given number of
subbands are vacant of PUs. In this multiple interrelated hypothesis testing problem, the noise variance is
estimated and a generalised likelihood ratio detector is proposed to identify possible spectrum holes at a
secondary user (SU). Provided that it is known that a specific PU can occupy a subset of subbands
simultaneously, a grouping algorithm which allows faster spectrum sensing is proposed. The collaboration of
multiple SUs can also be considered in order to enhance the detection performance. The collaborative
algorithms are compared in terms of the required exchange information among SUs in some collaboration
methods. The simulation results show that the propos Platform: |
Size: 231424 |
Author:phillis |
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Description: adaptive spectrum sensing using SNAR comparioson and relative doppler shift (effect) between primary and secondary user Platform: |
Size: 1024 |
Author:hossein |
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Description: 认知无线电技术的提出是为提高频谱利用率，而认知无线实现的关键技术是频谱感知，众所周知协作检测提高了衰落环境中认知用户系统检测的性能，该文章是基于协作检测提出新的检测方案，利用了双门限方法提高了系统性能，兼顾带宽有限和增强性能两个方面，是基于门限检测的协作检测性能优化的前提。对以后门限优化协作检测非常有用。-In this paper, we employ a double threshold method in energy detector to perform spectrum sensing, while a fusion center in the cognitive radio network collects the local decisions and observational values of the secondary users, and then makes the final decision to determine whether the primary user is absence or not. Simulation results will show that the spectrum sensing performance channels is improved significantly under the proposed scheme as opposed to the conventional method. Platform: |
Size: 374784 |
Author:丽丽 |
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Description: This thesis about Game therory which is aprotocol or alogrithm used in cognitive radio technology and used to manage or allocate sub-spectrum to secondary user or unlicensed users in CRN Platform: |
Size: 388096 |
Author: |
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Description: binary information regarding matlab code for cognitive radio. primary user and secondary users sense the spectrum using co operative sensing scheme Platform: |
Size: 7168 |
Author:sri |
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Description: binary information regarding matlab code for cognitive radio. primary user and secondary users sense the spectrum using co operative sensing scheme Platform: |
Size: 43008 |
Author:sri |
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Description: binary information regarding matlab code for cognitive radio. primary user and secondary users sense the spectrum using co operative sensing scheme Platform: |
Size: 1024 |
Author:sri |
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Description: 认知无线电中频谱共享的方法。是基于动态频谱租用的，运用了博弈论的原理。-Hierarchical dynamic spectrum access (DSA) has
received the most attention in recent years as the solution for
better spectrum utilization. In this paper, on the other hand,
we develop a framework for dynamic spectrum leasing (DSL).
Power control in hierarchical DSA networks only involves that of
controlling secondary user transmissions. Thus, in game theoretic
formulations of power control in cognitive DSA networks only
secondary users are considered as players of the game. In
proposed dynamic spectrum leasing, on the other hand, the
primary users are rewarded for allowing secondary users to
operate in their licensed spectrum. Thus, in the proposed DSL
networks the primary users have an incentive to allow secondary
users to access the spectrum whenever possible to the maximum
extent. We develop a game theoretic framework for such dynamic
spectrum leasing in which primary users actively participate in
a non-cooperative game with secondary users by selecting an
interfere Platform: |
Size: 368640 |
Author:刘小洋 |
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Description: 协作频谱感知虽然可提高系统的感知性能， 但随着感知节点数目的增加， 系统资源的占用越来越多，
系统传输效率下降． 分析了协作频谱感知方法的感知性能， 得到协作频谱感知的感知性能与感知节点数目和接
收信噪比之间的关系， 提出了一种新的次级用户节点的选择方法， 该方法有效保证了所选择节点的感知性能，
仿真验证了该算法的有效性和可靠性．-Although the cooperative spectrum sensing can improve the perceived performance of the system, but with the perception of the number of nodes increases, more and more system resources, the system transmission efficiency decreased. Cooperative spectrum sensing method of analysis of the perceived performance of collaborative spectrum sensing by the perception of performance and perception of the number of nodes and the relationship between the received SNR, a new secondary user node selection method, which effectively guarantee perceived performance of the selected node, the simulation proves the validity and reliability. Platform: |
Size: 1068032 |
Author:江中 |
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Description: 轻武器权限申请程序等外侧段v二大王我我的2的1我-In cognitive radio networks, power control is considered as an important issue to improve the performance of dynamic spectrum sharing. In this paper, in order to maximize the efficiency of the system, the secondary users and primary user behaviors will be considered. Platform: |
Size: 9216 |
Author:武款 |
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Description: 网对此说道稳定调查单位为氮测定法v稳定成为当刺猬刺猬刺猬侧完成单位从汶川-In cognitive radio networks, power control is considered as an important issue to improve the performance of dynamic spectrum sharing. In this paper, in order to maximize the efficiency of the system, the secondary users and primary user behaviors will be considered. Platform: |
Size: 3072 |
Author:武款 |
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Description: 额度为单位对身材C阿萨css彻底删除维多西奇舞动长裙策维持稳定从万达cdc档次低vvcd-In cognitive radio networks, power control is considered as an important issue to improve the performance of dynamic spectrum sharing. In this paper, in order to maximize the efficiency of the system, the secondary users and primary user behaviors will be considered. Platform: |
Size: 1024 |
Author:武款 |
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Description: 稳定时期为单位汽车完善的需求为单位DDFCWECDWCSCSC测定出稳定舞动长裙生产线-In cognitive radio networks, power control is considered as an important issue to improve the performance of dynamic spectrum sharing. In this paper, in order to maximize the efficiency of the system, the secondary users and primary user behaviors will be considered. Platform: |
Size: 1024 |
Author:武款 |
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Description: In last decades, the demand of wireless spectrum has
increased rapidly with the development of mobile communication
services. Recent studies recognize that traditional fi xed spectrum
assignment does not use spectrum effi ciently. Such a wasting
phenomenon could be amended after the present of cognitive
radio. Cognitive radio is a new type of technology that enables
secondary usage to unlicensed user. This paper presents an
Opportunistic Cognitive MAC Protocol (OC-MAC) for cognitive
radios to access unoccupied resource opportunistically and coex-
ist with wireless local area network (WLAN). By a primary traffi c
predication model and transmission etiquette, OC-MAC avoids
producing fatal damage to licensed users. Then a ns2 simulation
model is developed to evaluate its performance in scenarios with
coexisting WLAN and cognitive network.-In last decades, the demand of wireless spectrum has
increased rapidly with the development of mobile communication
services. Recent studies recognize that traditional fi xed spectrum
assignment does not use spectrum effi ciently. Such a wasting
phenomenon could be amended after the present of cognitive
radio. Cognitive radio is a new type of technology that enables
secondary usage to unlicensed user. This paper presents an
Opportunistic Cognitive MAC Protocol (OC-MAC) for cognitive
radios to access unoccupied resource opportunistically and coex-
ist with wireless local area network (WLAN). By a primary traffi c
predication model and transmission etiquette, OC-MAC avoids
producing fatal damage to licensed users. Then a ns2 simulation
model is developed to evaluate its performance in scenarios with
coexisting WLAN and cognitive network. Platform: |
Size: 177152 |
Author:eng |
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Description: The combining rules considered in this study are the OR hard combining rule, AND the hard combining rule, the Equal Gain Soft combining rule and the two-bit quantized (softened hard) combining rule. For all combining rules, the detection performance, with a Gaussian distribution assumption, is expressed in two different scenarios, CPUP (Constant Primary User Protection) and CSUSU (Constant Secondary User Spectrum Usability). Platform: |
Size: 386048 |
Author:suchita |
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Search - secondary user spectrum