Pilot-Aided Channel Estimation for 4×4 MIMO-OFDM in Multi-Gigabit Wireless Communication Systems

This paper investigates channel estimation techniques and equalization using singular value decomposition for 4 × 4 multiple-input multiple-output orthogonal frequency division multiplexing systems employed in multi-gigabit wireless communication systems. To achieve high spectral efficiency, the system utilizes spatial multiplexing with independent data streams transmitted on each antenna and employs high-order quadrature amplitude modulation (QAM), such as 1024-QAM and 4096-QAM. The study explores various pilot symbol placement strategies and robust estimation algorithms, including least squares. The pilot-based channel matrix learning with average to minimize noise is proposed. The system numerical simulation performance shows that the proposed method provides a high accuracy of channel matrix estimation. The mean squared error below 10<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-4</sup> can be achieved. Additionally, the proposed method is very simple and can be implemented in hardware.