共查询到20条相似文献,搜索用时 112 毫秒
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本文研究了QAM系统的盲均衡问题,提出了一个基于二阶、四阶矩的统计量匹配盲均衡准则,并由此导出了一种新的盲均衡算法,从而也加深了对盲均衡的理论认识。 相似文献
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本文给出了一种基于虚拟仪器的通讯系统,它的接收端利用盲均衡算法去除通讯系统中的码间干扰(ISI). 相似文献
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一种适用于MPSK调制的混合型盲均衡算法 总被引:1,自引:0,他引:1
提出了一种特别适用于MPSK信号的混合型盲均衡算法,理论分析和计算机模拟表明,这种混合型盲均衡算法的收敛性能与Godard类盲均衡算法的收敛性能相同,而误码性能优于Godard类盲均衡算法,并接近系统LMS均衡算法的性能,是一种具有实用价值的盲均衡算法。 相似文献
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对SIMO系统来说,盲语音去混响过程就是将接收到的未知多通道输出的卷积信号进行盲反卷积并得到源信号的过程。盲反卷积需要先盲辨识多信道脉冲响应,再对信号反卷积。在时域上,可以利用卡尔曼滤波器(KF)同步对SIMO系统及其逆系统进行盲多信道识别来实现盲反卷积,但是计算量较大。在深入分析时域算法的基础上,将部分时域计算变换到频域计算,通过快速傅里叶变换(FFT)代替卷积计算,从而大大降低算法的总计算量。仿真实验表明,用部分频域算法取代时域算法,在保证算法稳定性的同时可以明显改善算法的收敛速度,降低算法的复杂度。 相似文献
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基于非线性盲源分离的维纳系统算法中,采用固定步长导致算法的收敛速度和稳态误差之间存在矛盾,直接影响分离算法的性能。为了解决该问题,提出了基于非线性函数的变步长维纳系统盲源分离方法。该方法将更新的步长以非线性函数的形式引入到分离算法中,使得稳态时参数更新的步长尽可能小,以避免发生振荡。变步长算法在分离过程中的每次更新都会使步长自动进行合理的调整,使得收敛速度提高了53%,误差减小了45%。实验仿真表明,相对原算法,提出的维纳系统盲源分离方法可以更好地分离出信源信号,而且具有较小的误差和较快的收敛速度。 相似文献
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提出一种基于小波域图像纹理特征的彩色图像盲水印算法。该算法根据。图像小波变换后小波系数的特点选择视觉重要系数,量化嵌入二值水印序列。利用人类视觉系统的纹理掩蔽特性和照度掩蔽特性自适应调整量化间距,以保证水印的透明性。算法实现了水印的盲检测。仿真实验的结果表明,算法对各种常用的水印攻击方法具有较好的鲁棒性。 相似文献
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一种新型盲均衡算法—RG算法的研究 总被引:1,自引:0,他引:1
本文提出了一种新的盲均衡算法-RG算法,它保持了Godard盲均衡算法收敛性能好的特点,其误码性能也优于Godard盲均衡算法,尤其是对MPSK调制系统。理论分析及计算机模拟表明,RG算法是一种性能优良的盲均衡算法。 相似文献
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本文提出了一种新的盲均衡算法-RG算法,它保持了Godard盲均衡算法收敛性能好的特点,其误码性能也优于Godard盲均衡算法,尤其是对MPSK调制系统。理论分析及计算机模拟表明,RG算法是一种性能优良的盲均衡算法。 相似文献
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This work aims to show the effectiveness of a recently proposed population-based optimization algorithm known as Jaya algorithm and its variants named as self-adaptive Jaya algorithm (SJaya) and Chaotic-Jaya (CJaya) algorithm to synthesize linear antenna arrays which are widely used in the communication systems. Three case studies of synthesis of linear antenna arrays are formulated by considering different topologies. In addition, two case studies of synthesis of dipole antenna arrays are formulated and all the case studies are solved using Jaya, SJaya and CJaya algorithms. The results of Jaya, SJaya and CJaya algorithms are compared with those of cat swarm optimization (CSO) algorithm, particle swarm optimization (PSO), Cauchy mutated cat swarm optimization (CMCSO) algorithm, harmony search based differential evolution algorithm (HSDEA), dynamic differential evolution algorithm (DDE), improved genetic algorithm (IGA), modified real genetic algorithm (MGA) and accelerated particle swarm optimization (APSO) algorithm. The Jaya, SJaya and CJaya algorithms achieved a better side lobe level suppression as compared to the other optimization algorithms while maintaining the vital antenna parameters within permissible limits. 相似文献
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With the development of wireless and personal communication systems, there is considerable interest in using antenna array technology to improve the system capacity in both present and future generation wireless systems. A novel and simple algorithm is proposed for blind adaptive extraction of a binary phase-shift keying (BPSK) signal in the presence of interference by cyclostationary signal processing using an antenna array. The algorithm operates in an interference-limited system in which the desired and interfering signals have identical symbol rates, but are modulated on slightly different carrier frequencies. Compared to existing blind algorithms which also exploit the cyclostationarity of the received signal, the new algorithm provides a simpler and faster converging means to estimate the channel phase for diversity combining. Analytical and simulation results are presented and performances are compared with direct matrix inversion (DMI) and existing blind algorithms. Based on the proposed algorithm and the result obtained by Gardner, Schell and Murphy (1992), a time-division multiple-access (TDMA) system with the new channel assignment scheme called cyclic TDMA (CTDMA) is proposed. The simulation results also show that the proposed algorithm is relatively simple and very promising in applications to indoor wireless communication where interference rejection and increased spectrum efficiency are the objectives. Analysis and simulation results are presented to confirm the interference rejection capabilities. The robustness of existing and proposed algorithms to the perturbation of cyclostationarity is also discussed 相似文献
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在大规模多输入多输出(massive MIMO)系统中使用天线选择算法可提高能效和系统吞吐量,然而适用于传统MIMO系统的天线选择算法具有高复杂度,很难用于massive MIMO系统。为优化天线选择算法,以算法复杂度和系统容量为优化目标,提出了收发联合阈值天线选择算法。该算法在发射端使用最大范数双向天线选择算法进行天线选择,在接收端使用分组maxvol算法并通过仿真实验结果的预设阈值进行天线选择。仿真实验表明,收发联合阈值天线选择算法在降低复杂度的同时可以提高系统容量,与递增天线选择算法相比,系统容量最多可提高52.2 bit/s/Hz。提出的天线选择算法可以满足不同天线相关度和信噪比的传输环境。 相似文献
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自适应天线的空间信号处理能力证明了它是解决未来无线电通信容量瓶颈问题的主要措施之一。自适应天线的波束形成算法有很多,简单介绍了LMSE(Least Mean Square Error)算法、CMA(Constant Modulus Algorithm)算法,重点讨论了一种基于最小误比特(Least Bit Error Rate,LBER)的自适应天线空间波束形成算法,从误比特率的角度对这三种算法进行了仿真、比较,得出了分析结果。 相似文献
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多天线是天线技术的发展趋势,TD-LTE引入了8发2收的天线配置.基于小间距多天线阵列,利用TDD系统信道互易性,波束赋形技术可以根据上行导频获得信道信息,形成对基带(中频)信号的最佳组合或者分配,补偿无线传播过程中由空间损耗、多径效应等因素引入的信号衰落与失真,同时降低同信道用户间的干扰.EBB(Eigen-based Beamforming)算法是波束赋形主要算法之一,该算法中在整个波束空间中,找到使接收信号功率最大的赋形权矢量.通过仿真,对EBB算法在各种应用场景下的性能进行了分析,结果表明八天线EBB波束赋形算法可以正确实现波束合成,在低速或上行信道信息估计误差较小情况下能够明显提高系统性能. 相似文献
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In this paper, based on the phase-position perturbation method, an
innovative optimal adaptive antenna technique is proposed, where the
deduced radiation pattern formulas available for searching optimal
solutions are used to search the optimal weighting vector. The
optimal radiation pattern designs of adaptive antenna are studied by
the phase-position perturbation method. Memetic algorithms are used to
search the optimal weighting vector of the phase-position
perturbations for the array factor. The design for an optimal
radiation pattern of an adaptive antenna can not only adjustably
suppress the interferers by placing nulls at the directions of the
interfering sources, but at the same time provide a maximum main
lobe in the direction of the desired signal, i.e., to maximize the
signal-to-interference ratio. To achieve this goal, a
new convergent method, referred to as the two-way convergent method
for memetic algorithms, is proposed. The memetic algorithm combines
a genetic algorithm and local search heuristics to solve combinatorial
optimization problems. The memetic algorithm is a kind of improved
type of the traditional genetic algorithm. By using a local search
procedure, it can avoid the shortcomings of the traditional genetic
algorithm, whose termination criteria are set up by using the trial
and error method. This proposed method is also able to solve the
multipath problem, which exists at the same time in this
communication system. The optimal radiation pattern concept can be
implemented in practical wireless communication systems. Simulation
results are also given in this paper. 相似文献
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A noncentralized fully distributed mobile communication network with directive/adaptive antennas is proposed. The spatial and temporal synchronization of transmitting and receiving antenna beams is accomplished by employing the global positioning system information and a synchronized spatial search algorithm. The link setup between a communication transmitter (CT) and a communication receiver (CR) depends on the success of both forward and reverse links. A two-way communication link protocol is defined as a basic agreement for the link activation in the network. Two link search algorithms, for additive white Gaussian noise channels, are proposed for use in hostile communication environments as follows: (1) a sequential ascending search power algorithm using an optimal set of link power levels and (2) a sequential Bayesian search algorithm (SBSA) using Bayes rule to update the CR location information. The optimal SBSA can be obtained by using dynamic programming, but the computational complexity is unfeasibly high. The experimental results in which the CT uses a noncoherent matched filter receiver for spread-spectrum code acquisition and the unfriendly interceptor uses a wide-band energy detector for both link search algorithms are presented 相似文献