共查询到17条相似文献,搜索用时 148 毫秒
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本文针对认知无线电系统中的远近不公平性,提出将信道增益因子引入到基于信干比(SIR)的分布式非合作博弈功率控制算法中,并证明了其纳什均衡的存在性及唯一性。同时在此算法的基础上,针对部分用户的SIR不能满足下限阀值的情况,设计了一种新的自适应加权系数以控制发射功率,满足不同用户的输出SIR需求。仿真结果表明,与其它的分布式功率控制算法相比,该算法不仅有效地解决了远近不公平现象,满足了认知用户公平共享频谱资源的需求,同时使认知用户的SIR能同时满足上下限阀值的要求,且具有快速收敛的特性。 相似文献
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本文基于Goodman提出的非合作博弈功率控制模型改进了代价函数。针对感知无线电系统(CR)中各用户的通信需求,采用多载波码分多址(MC-CDMA)感知无线电系统,解决感知用户对主用户干扰和通信中断等问题,为实现感知频谱资源的有效分配,提出了一种新的感知无线电系统功率控制博弈算法。通过仿真表明,该算法同几种经典算法相比,既满足不同种类用户SIR要求,又提高了系统吞吐量,实现了对不同用户发射功率的有效控制,且系统性能明显提高。 相似文献
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认知无线电中基于Stackelberg博弈的分布式功率分配算法 总被引:1,自引:0,他引:1
在underlay认知无线电场景中,为了让认知用户能随机地接入主用户正在使用的授权频段,且对主用户产生的干扰不高于主用户能够容忍的干扰温度门限,该文采用Stackelberg博弈机制进行认知用户的发射功率分配。将主用户作为模型中的leader,认知用户作为follower,认知用户使用主用户的授权频段时需以干扰功率为单位支付给主用户相应的费用,而主用户则可以通过调整价格,限制认知用户产生的总干扰功率不高于其所能容忍的干扰温度门限,以便获得最大收益。同时,不同认知用户间根据主用户制定的价格,进行非协作博弈。仿真结果表明,与集中式的最优功率分配算法相比,该文可通过简单的分布式功率分配算法获得与其相近的系统性能,且主用户与认知用户间只需进行少量的信息交互,这与需进行大量信息交互的集中式最优算法相比,具有较大的优势。 相似文献
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分布式功率控制是认知无线电(CR)系统中的关键技术之一,它直接影响到无线系统的性能。本文采用了博弈论的方法来实现对CR用户的分布式功率控制,在David Goodman的非协作博弈算法的基础上,给出了一种改进的效用函数,它使各用户在满足要求信干比条件下发送功率最小,同时使整个系统内由各种干扰引起的失真最小。本文通过理论推导证明了新的效用函数存在纳什均衡,并且均衡点唯一,同时仿真验证了该算法的收敛性,仿真结果表明这种兼顾用户自身利益以及用户间公平性的效用函数能降低发送功率,并且有效提高CR系统的性能。 相似文献
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Joint spatial-frequency blind multiuser detection based on LCCMA 总被引:1,自引:0,他引:1
ZHAO Fa-yong FENG Guang-zeng Department of Communication Information Engineering Nanjing University of Posts Telecommunications Nanjing China 《中国邮电高校学报(英文版)》2007,14(2):19-22
Multicarrier code division multiple access (MC-CDMA) has the ability to combat with frequency selective fading and antenna array can enhance the performance of system. The paper proposes a novel joint spatial-frequency blind multiuser detection for antenna array MC-CDMA based on linear constraint constant modulation algorithm (LCCMA), which has robust performance and can ensue the weight vectors to converge to that of the desired user. Simulation indicates the proposed algorithm has better bit error ratio (BER) performance than that of the traditional beamforming-based two-step algorithm. 相似文献
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Santiago Mozos R. Fernandez-Getino Garcia M.J. 《Wireless Communications, IEEE Transactions on》2006,5(11):2992-2996
Maximum likelihood (ML) joint detection of multi-carrier code division multiple access (MC-CDMA) systems can be efficiently implemented with a sphere decoding (SD) algorithm. In this paper, we examine the application of complex instead of real SD to detect MC-CDMA, which solves many problems in a more elegant manner and extends SD adaptability to any constellation. We first propose a new complex SD algorithm whose efficiency is based on not requiring an estimate of the initial search radius but selecting the Babai point as the initial sphere radius instead; also, efficient strategies regarding sorting the list of possible lattice points are applied. Indeed, complex SD allows complex matrix operations which are faster than real counterparts in double dimension. Next, a novel lattice representation for the MC-CDMA system is introduced, which allows optimum multiuser detection directly from the received signal. This avoids noise whitening operation, and also despreading and equalization procedures are not required further at the receiver side 相似文献
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提出一种基于多带复小波和空时编码的多载波CDMA系统,研究了其在瑞利衰落信道下的误比特性能。理论分析和仿真结果表明该系统要明显优于通常MC-CDMA系统,具有与采用循环前缀(CP)的MC-CDMA相比较的优势,而且能够克服通常MC-CDMA系统插入CP所带来能量的减少和频谱效率的降低。同时空时编码技术的应用,显著增强了系统抗多径干扰和多址干扰的能力,进一步提高了系统性能。 相似文献
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针对STBC-MIMO MC-CDMA多用户检测方法存在计算复杂度高、工程实现困难的问题,提出利用一种混合量子进化算法(HQEA)解决STBC-MIMO MC-CDMA多用户检测问题,该算法不仅具有较低的计算复杂度,而且解决了量子进化算法容易陷入局部最优解、参数个数较多和通过查表来更新量子门的问题。仿真表明,该算法在STBC-MIMO MC-CDMA系统多用户检测问题上,具有比其他智能算法更强的跳出局部最优和寻找全局最优的能力。 相似文献
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Ali Reza Enayati Paeiz Azmi Yaghoob Taghinia Ahmad Salahi 《Telecommunication Systems》2012,50(2):71-88
Multiuser-detection (MUD), turbo coding and smart-antennas (SA) are powerful techniques for enhancing the performance and capacity of MC-CDMA systems. Among the MUD algorithms, the maximum-likelihood (ML) method has the best performance but its complexity increases exponentially with the number of users and constellation size. In this paper, we first propose a novel bandwidth-efficient-channel-coding-scheme (BECCS) for a super-orthogonal-code (SOC)-based serially concatenated turbo code (SCSOC) so that by using it, the coded system without extra bandwidth significantly improves the performance of an uncoded system over a fading channel. Second, in order to reduce the complexity of the ML-based turbo MUD technique, an ML algorithm based on the sensitive-bits-algorithm (SBA) and a less-complex-norm-approximation (LCNA) based Euclidean distance is proposed for a SCSOC-based BECCS assisted coded MC-CDMA system accompanied by SA techniques at the receiver. Our analytical and simulation results show that from a performance perspective, at BER=10?2, the proposed SCSOC-based BECCS assisted MC-CDMA system performs 4?dB better than SOC-based coded systems. The latter system has 5?dB gain in comparison with an uncoded one, all in the same bandwidth and over fading channels. 相似文献
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Kan Zheng Guoyan Zeng Wenbo Wang 《Broadcasting, IEEE Transactions on》2005,51(1):144-148
In this paper, a novel OFDM-CDMA system with joint time-frequency spreading methods is proposed. The average bit error probability of the proposed system using maximum-ratio combining (MRC) is derived for a frequency-selective fading channel and that of conventional MC-CDMA is also presented for comparison. Numerical analysis and simulation results indicate that the proposed system outperforms MC-CDMA system. 相似文献