EM-based semi-blind channel estimation method for MIMO-OFDM communication systems

This paper presents a novel semi-blind method for channel estimation and symbol detection in multiple input multiple output–orthogonal frequency division multiplexing (MIMO-OFDM) digital communication systems over time-varying channels where the standard pilot-aided channel estimation (PACE) interpolation approaches are not directly applicable due to insufficient placement of pilot sequences over the frequency sub-channels. The presented channel estimation method utilizes the Expectation Maximization (EM) algorithm to exploit the information in the received signals and the statistical properties of the channel.