共查询到20条相似文献,搜索用时 93 毫秒
1.
基于正交多相序列的OFDM信道估计算法 总被引:1,自引:0,他引:1
提出了一种基于正交多相序列的OFDM信道估计算法。该算法采用相关性能良好的正交多相序列作为发送信号的循环前缀,在接收端,提取循环前缀,进行相关计算,最终得到系统频域响应的估计值。通过仿真,验证了在多径衰落信道中,提出的算法比频域梳状导频插入的时域滤波算法及采用小m序列作为循环前缀的信道估计算法具有更高的信道估计精度。 相似文献
2.
3.
4.
5.
6.
7.
8.
研究了移动信道中的最大多普勒频移估计技术。分析了一种基于循环前缀的多普勒频移估计算法,该算法通过计算正交频分复用(OFDM)符号已有的循环前缀的相关函数来获得最大多普勒频移。采用广义平稳非相关散射下的多径时变瑞利信道模型,对各个算法进行了仿真试验,比较了各个算法的性能。仿真结果表明,利用多普勒分集技术,可以显著降低误码率,提高系统在移动环境下的性能。 相似文献
9.
导频辅助信道估计法是OFDM(Orthogonal Frequency Division Multiplexing)系统中的主要信道估计方法,使用LS方法估计导频点处的信道响应,然后使用插值法可以获得信道的全响应.本文详细介绍了各种插值算法,包括线性插值算法、高斯插值算法和基于DFT的插值算法.所有涉及到的插值算法的应用背景是数字地面电视系统(DVB-T,Digital Video Broadcasting-Terrestrial).应用于测试系统,我们将对比分析三种算法的均方误差性能和运行时间性能. 相似文献
10.
本文提出一种适用于多径频率选择性衰落信道中多用户OFDM系统的自适应分配算法.算法根据信道瞬时估计值,自适应地为多用户分配子信道和传输比特数,在给定误比特率的条件下,使系统总的发送功率达到最小.作者根据时分复用的基本思想,提出多用户最佳子信道和比特分配算法,导出系统最小发送功率的下限,并在此基础上,进一步提出次佳自适应分配算法.数值模拟表明:次佳算法所需的发送功率比下限值高约1dB;与等比特分配方案相比自适应分配算法可节省功率约3-4dB;与静态信道分配方案相比,自适应分配算法可节省功率6-8dB. 相似文献
11.
Multicarrier modulation (MCM) is a promising technique for high rate data transmission and the channel estimation is very important for the implementation of MCM. We found that the cyclic prefix, originally used solely to reduce the intersymbol interference (ISI), can be viewed as a source of channel information. Based on this observation, we propose an adaptive channel estimation algorithm using the cyclic prefix. This algorithm can adaptively track the channel variation without additional training sequences 相似文献
12.
与传统的正交频分复用(OFDM)频域信道估计方法不同,提出了一种循环前缀为PN序列的OFDM信道估计方法:在时域OFDM符号中不插入传统意义上的循环前缀,而是插入PN序列作为训练序列,将PN序列与对应的接收序列作圆周相关处理获得信道频率响应估计;而由于PN序列周期性出现,它也起到了循环前缀的作用。仿真结果表明:在多径瑞利衰落信道中,在相同信噪比和相同信道利用率的条件下,提出的算法比频域梳状导频插入的时域滤波算法具有更高的信道估计精度。 相似文献
13.
智能天线系统中上行多用户相干信号的分离与DOA估计方法研究 总被引:3,自引:0,他引:3
本文研究了平主道中的窨特征估计问题。提出了一种工于循环累量的多用户空间牲针该算法用于智能天线中的SDMA实现。该算法构造了循环累量域四,通过对空间特征循环矩阵的特征分解可以得到用户信号的空间特征估计。并以此为基础,设计了用于上行多波束成形的窨滤波器组实现了上行多用户信号的分离,利用空间滤波器的空间频率响应确定共信道多用户信号的DOA《 相似文献
14.
In time varying channels, symbol recovery for single carrier cyclic prefix (SCCP) systems becomes complicated, because the orthogonality of channel frequency response (CFR) matrix is destroyed. In response, we propose a block turbo equalization algorithm in the time domain for SCCP to cope with channel time variations. In particular, the band structure of the channel time response (CTR) matrix is exploited to reduce the computational complexity of matrix inversion. In order to use this equalization scheme, accurate channel state information (CSI) must be available. Accordingly, we present a doubly selective channel estimation method for SCCP block transmissions with the aid of a Karhunen-Loeve basis expansion model (KL-BEM). In this method, the channel estimates are firstly obtained by using the cyclic prefix (CP) of each block, and then further refined by employing an expectation maximization (EM) based iterative algorithm. Combining the iterative estimator with the proposed equalizer naturally results in a doubly iterative receiver, the performance of which is shown to come close to the performance with perfect CSI. 相似文献
15.
Multicarrier modulation (MCM) has gained growing interest in high-data-rate communications in both wire and wireless environments. The channel estimation is a crucial aspect in MCM systems. In this paper, we first present a novel adaptive channel estimation algorithm exploiting the channel information contained in the cyclic prefix of the MCM system. In simulation, we show that this algorithm outperforms the existing scheme. Then we theoretically analyze the performance of the adaptive algorithm considering both channel noise and decision error. We prove that the algorithm is guaranteed to converge with proper loading. Computer simulation shows that our analytical results are quite close to the simulation. 相似文献
16.
A novel channel estimation algorithm is presented in this paper for the recently proposed cyclic postfix based on orthogonal frequency division multiplexing (OFDM) systems. Phase equalization with the erasure decision is used to reduce both the channel estimation error and the computational complexity. Simulation results show that the proposed channel estimation algorithm can effectively estimate the channel impulse response (CIR) and the performance of the proposed phase equalization with erasure decision is comparable with the minimal mean square error (MMSE) equalization, but it offers less computational complexity. 相似文献
17.
18.
19.
无循环前缀OFDM无线通信系统可以提高频谱利用效率。提出一种基于无循环前缀(CP)OFDM系统的联合信道估计和干扰抵消算法。采用最小二乘法(Least Square)估计信道时域矢量,通过离散傅里叶变换(DFT)得到相应的OFDM信道的频域特性,由迭代算法对信号进行联合检测和干扰抵消。仿真结果表明,信道估计结果能够达到较高的精度,误码率也接近有循环前缀的OFDM无线通信系统。 相似文献
20.
基于均值循环卷积特性的UWB信道盲估计算法 总被引:3,自引:0,他引:3
该文针对采用码片率抽头间隔的TH-PPM超宽带系统离散信道,利用接收信号的均值循环卷积特性,对UWB信道估计问题进行建模,结合UWB信道的稀疏簇结构,提出一种基于抽头探测的UWB信道盲估计算法,避免了无谓的零抽头估计,改善了算法性能。仿真表明:在低信噪比(0-15dB)的情况下,基于抽头探测算法的MSE比没利用信道结构特征的最小二乘算法平均低约5.5dB;在中等信噪比(15dB)的情况下,基于抽头探测算法的MSE比最小二乘算法平均低约3.5dB,同时基于抽头探测算法还能获得较好的SER(Signal-Error-Ratio)性能。 相似文献