Estimation of FBMC/OQAM Fading Channels Using Dual Kalman Filters

Mahmoud Aldababseh,Ali Jamoos

doi:10.1155/2014/586403

Abstract

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.

Highlights

Wireless multicarrier (MC) communication systems are parallel data transmission techniques in which high data rates can be achieved by the simultaneous transmission over many orthogonal subcarriers [1]
We propose to investigate the relevance of the dual Kalman filters for the estimation of filter bank multicarrier (FBMC)/OQAM time-varying fading channels based on pilot symbols
We carry out a comparative simulation study on the estimation of FBMC/OQAM fading channels between the proposed dual Kalman filters based channel estimator and the conventional least mean square (LMS) and recursive least square (RLS) channel estimators

Summary

Introduction

Wireless multicarrier (MC) communication systems are parallel data transmission techniques in which high data rates can be achieved by the simultaneous transmission over many orthogonal subcarriers [1]. When classical channel estimation methods used for OFDM systems are applied directly to FBMC/OQAM system, an intrinsic intersymbol-interference is observed We propose to investigate the relevance of the dual Kalman filters for the estimation of FBMC/OQAM time-varying fading channels based on pilot symbols. The transmitted FBMC/OQAM signal y[m] in (1) is assumed to go through a time-varying frequency-selective Rayleigh fading channel with background additive white Gaussian noise (AWGN). After processing the received signal rk[m] with the analysis filter bank block, the resulting signal at the input of channel estimation and equalization is given by sk [n] = [rk [m] ∗ fk [m]]↓M/2 (12). As the Doppler rate fdTs is usually unknown, we propose to complete the joint estimation of the fading process hk[n] and its AR parameters {ai}i=1,2,...,p based on dual Kalman filters.

Dual Kalman Filters Based

Simulation Results

Conclusions

Conflict of Interests