A Completely Blind Channel Estimation Technique for OFDM Using Generalized Constellation Splitting and Modified Phase-Directed Algorithm

The problem of blind channel estimation for SISO-OFDM systems using second-order statistics (SOS) is addressed. A comparison of two prominent SOS-based techniques: subspace-decomposition and precoding-induced correlation-averaging techniques in terms of MSE performance is presented. The drawback of these methods is that they suffer from a complex-scalar estimation ambiguity which is resolved by using pilots or reference symbols. By using pilots the whole purpose of blind techniques is contradicted. We propose an algorithm to resolve this ambiguity in blind manner using generalized constellation-splitting and modified phase-directed algorithm. The performance of the proposed scheme is evaluated via numerical simulations in MATLAB environment.