Aldababseh Mahmoud, Jamoos Ali
Department of Electronic Engineering, Al-Quds University, P.O. Box 20002, Jerusalem, Palestine.
ScientificWorldJournal. 2014 Feb 18;2014:586403. doi: 10.1155/2014/586403. eCollection 2014.
We address the problem of estimating time-varying fading channels in filter bank multicarrier (FBMC/OQAM) wireless systems based on pilot symbols. The standard solution to this problem is the least square (LS) estimator or the minimum mean square error (MMSE) estimator with possible adaptive implementation using recursive least square (RLS) algorithm or least mean square (LMS) algorithm. However, these adaptive filters cannot well-exploit fading channel statistics. To take advantage of fading channel statistics, the time evolution of the fading channel is modeled by an autoregressive process and tracked by Kalman filter. Nevertheless, this requires the autoregressive parameters which are usually unknown. Thus, we propose to jointly estimate the FBMC/OQAM fading channels and their autoregressive parameters based on dual optimal Kalman filters. Once the fading channel coefficients at pilot symbol positions are estimated by the proposed method, the fading channel coefficients at data symbol positions are then estimated by using some interpolation methods such as linear, spline, or low-pass interpolation. The comparative simulation study we carried out with existing techniques confirms the effectiveness of the proposed method.
我们研究了基于导频符号估计滤波器组多载波（FBMC/OQAM）无线系统中时变衰落信道的问题。该问题的标准解决方案是最小二乘（LS）估计器或最小均方误差（MMSE）估计器，并可能使用递归最小二乘（RLS）算法或最小均方（LMS）算法进行自适应实现。然而，这些自适应滤波器无法很好地利用衰落信道统计信息。为了利用衰落信道统计信息，衰落信道的时间演变通过自回归过程进行建模，并由卡尔曼滤波器进行跟踪。然而，这需要通常未知的自回归参数。因此，我们提出基于双最优卡尔曼滤波器联合估计FBMC/OQAM衰落信道及其自回归参数。一旦通过所提出的方法估计出导频符号位置处的衰落信道系数，然后使用诸如线性、样条或低通插值等一些插值方法来估计数据符号位置处的衰落信道系数。我们与现有技术进行的对比仿真研究证实了所提出方法的有效性。
