Iterative Decision Directed Channel Estimation for BICM-Based MIMO-OFDM Systems

Iterative Decision Directed Channel Estimation (DDCE) scheme is proposed in this paper for bit interleaved coded modulation (BICM)-based MIMO-OFDM systems. The proposed scheme employs Variable Step Size Normalized Least Mean Square (VSSNLMS) algorithm to implement its temporary Channel Transfer Function (CTF) Estimator and Adaptive Channel Impulse Response (CIR) predictor modules, while Fast Data Projection Method (FDPM) algorithm is employed to track the time domain CIR of the MIMO channel. The proposed iterative DDCE operates in an iterative mode in conjunction with MIMO demappers and the Turbo decoder at receiver of the MIMO-OFDM system. The achievable performances of the proposed scheme in terms of both mean square error (MSE) and bit error rate (BER) are presented. Comparative performances between the DDCE scheme employing FDPM algorithm and another one employing deflated Projection Approximation Subspace Tracking (PASTd) algorithm are also given. The simulations results presented indicate better performances of the proposed scheme.