共查询到20条相似文献,搜索用时 46 毫秒
1.
单载波频域均衡(SC-FDE)是多输入多输出(MIMO)无线通信中克服多径衰落的一种重要技术。本文基于V-BLAST信号检测的原理,对MIMO-SC-FDE系统提出了以块为单位进行分层检测的块BLAST算法。在该算法中,系统按一定的准则确定对各路发送信号进行频域均衡和检测的顺序,较先检测出的信号被变换到频域作为干扰从接收信号中去除,使得对以后各路信号进行频域均衡和检测的信干噪比得以提高,从而大大改善了MIMO-SC-FDE系统的误码性能。仿真实验结果显示,块BLAST算法取得了大大优越于MIMO-SC-FDE常规检测算法的误码性能。 相似文献
2.
介绍了单载波频域均衡(SC-FDE)的原理和均衡实现的过程,并采用时域 LS 信道估计算法对频域均衡性能进行了仿真。 相似文献
3.
从对流层散射通信信道的特点出发,介绍了单载波频域均衡技术原理与系统结构,研究了可适用于对流层散射通信且易于工程实现的几种频域均衡算法,并创新性地研究了将单载波频域均衡技术与分集接收技术相结合的可行性及系统性能,在理论分析的基础上借助Matlab软件进行了仿真验证,给出了仿真结果,并对其进行了分析。仿真结果验证了算法的有效性以及单载波频域均衡技术与分集接收技术相结合的可行性,为其在散射通信系统中的应用和工程实现提供参考和指导。 相似文献
4.
5.
6.
分析了中国数字电视地面广播标准中的系统帧结构,并根据信号帧头的循环特性,提出了一种性能较好的信道估计 算法;分析了传统的单载波均衡算法的优缺点,提出了一种联合频域均衡和时域判决反馈的均衡技术;最后对U1信道进行仿 真,并对仿真结果进行分析总结. 相似文献
7.
无线信道中的单载波频域均衡技术 总被引:2,自引:0,他引:2
本文介绍了时域均衡的单载波系统、多载波正交频分复用系统和频域均衡的单载波系统。频域均衡单载波系统复杂度和性能与多载波系统相当,可以与多载波系统共存,已被IEEE 802.16建议在宽带无线接入中采用。 相似文献
8.
利用Xilinx公司的FPGA器件,实现单载波频域均衡的算法。针对实现过程中资源消耗较多的问题,提出了基于快速傅里叶变换/逆快速傅里叶变换的突发实现方法和除法的查找表实现方法,并通过集成软件环境(ISE)软件内嵌的综合工具对整个系统进行综合,查看在使用此2种实现方法时的现场可编程门阵列内部的资源消耗,并将其与使用传统方法时的资源消耗情况进行对比,从而证实了此2种实现方法对资源的节约,同时对频域均衡系统进行了仿真,验证了方案的可行性。 相似文献
9.
单载波频域均衡与多载波OFDM误码性能的理论比较 总被引:7,自引:0,他引:7
单载波频域均衡(SC-FDE)和多载波正交频分复用(OFDM)是数字通信中用于克服多径衰落的两种技术。本文通过理论推导对这两种技术在高斯白噪声通信信道巾的误码性能进行了比较。利用高斯分布尾部概率的数值变化特性,本文推导出如下结论:在低信噪比条件下,OFDM的误码性能略优于SC-FDE,而在高信噪比条件下,SC-FDE则能取得显著优于OFDM的误码性能。这一结论对于通信系统的设计具有重要的参考价值。 相似文献
10.
11.
In this paper, we formulate the problem of blind equalization of constant modulus (CM) signals as a convex optimization problem. The convex formulation is obtained by performing an algebraic transformation on the direct formulation of the CM equalization problem. Using this transformation, the original nonconvex CM equalization formulation is turned into a convex semidefinite program (SDP) that can be efficiently solved using interior point methods. Our SDP formulation is applicable to baud spaced equalization as well as fractionally spaced equalization. Performance analysis shows that the expected distance between the equalizer obtained by the SDP approach and the optimal equalizer in the noise-free case converges to zero exponentially as the signal-to-noise ratio (SNR) increases. In addition, simulations suggest that our method performs better than standard methods while requiring significantly fewer data samples. 相似文献
12.
The paper addresses the problem of blind equalization of constant modulus signals which are degraded by frequency selective multipath propagation and additive white noise. An adaptive observer is used to update the weights of an FIR equalizer in order to restore the signal's constant modulus property. The observer gain is selected using fake algebraic Riccati methods in order to guarantee local stability. The performance of this method is compared to the constant modulus algorithm for simulated FM-FDM signals and exhibits significantly better convergence properties, particularly for heavy-tailed noise 相似文献
13.
Blind equalization using the constant modulus criterion: a review 总被引:56,自引:0,他引:56
Johnson R. Jr. Schniter P. Endres T.J. Behm J.D. Brown D.R. Casas R.A. 《Proceedings of the IEEE. Institute of Electrical and Electronics Engineers》1998,86(10):1927-1950
This paper provides a tutorial introduction to the constant modulus (CM) criterion for blind fractionally spaced equalizer (FSE) design via a (stochastic) gradient descent algorithm such as the constant modulus algorithm (CMA). The topical decisions utilized in this tutorial can be used to help catalog the emerging literature on the CM criterion and on the behavior of (stochastic) gradient descent algorithms used to minimize it 相似文献
14.
15.
单载波频域均衡技术由于其能有效的对抗频率选择性衰落,成为被多种新兴高速率通信系统所推荐的关键技术之一.利用Matlab/Simulink组件,对单载波频域均衡系统进行了仿真实现.结果显示,单载波频域均衡系统的误码率保持在10-3的数量级上. 相似文献
16.
针对脉冲噪声下恒模算法(Constant Modulus Algorithm,CMA)失败的问题,通过分析脉冲噪声的影响,提出了一种基于最小均方(Least Mean Square,LMS)准则的对数型恒模算法(Logarithmic-type CMA,LT-CMA)。LT-CMA利用对数函数的非线性变换特性自适应地抑制强脉冲噪声对误差函数的影响,并且利用l2-范数进行信号归一化处理以增强算法的稳健性。仿真结果表明,所提出的LT-CMA可以适应于高斯噪声环境和脉冲噪声环境;与经典自适应均衡算法相比,在收敛速度和稳健性两方面上,所提出的LT-CMA都有显著的提升。 相似文献
17.
Carlos Alexandre R. Fernandes Gérard Favier Joao Cesar M. Mota 《Signal, Image and Video Processing》2007,1(4):333-346
In this paper, new decision directed algorithms for blind equalization of communication channels are presented. These algorithms
use informations about the last decided symbol to improve the performance of the constant modulus algorithm (CMA). The main
proposed technique, the so called decision directed modulus algorithm (DDMA), extends the CMA to non-CM modulations. Assuming
correct decisions, it is proved that the decision directed modulus (DDM) cost function has no local minima in the combined
channel-equalizer system impulse response. Additionally, a relationship between the Wiener and DDM minima is established.
The other proposed algorithms can be viewed as modifications of the DDMA. They are divided into two families: stochastic gradient
algorithms and recursive least squares (RLS) algorithms. Simulation results allow to compare the performance of the proposed
algorithms and to conclude that they outperform well-known methods. 相似文献
18.
19.
单载波频域均衡(SC-FDE)技术具有发送信号低峰均功率比的优势,是新一代通信3GPP-LTE/LTE-Advanced上行链路的关键技术之一。针对非理想信道估计,基于信道估计误差的统计模型,提出了一种联合频域均衡和时域判决反馈的鲁棒接收均衡器。以最小化均方误差(MSE)为最优准则,推导了均衡器的系数和均方误差的表达式。仿真结果表明,这种鲁棒的混合均衡器在非理想信道估计下较传统均衡器具有显著的性能提升。 相似文献
20.
Single-carrier frequency domain equalization 总被引:4,自引:0,他引:4
《Signal Processing Magazine, IEEE》2008,25(5):37-56