Blind channel estimation algorithm for OFDM-MIMO systems
Yan Yao · Journal of Tsinghua University(Science and Technology) · 2005
In order to solve the identification confusion in multi-input-multi-output (MIMO) systems, an efficient blind channel estimation algorithm based on second-order statistics was developed for orthogonal frequency division multiplexing multi-input-multi-output (OFDM-MIMO) systems. The algorithm analyzes the system in the frequency domain, then simplifies the finite-impulse-response channel estimate into several memoryless systems. The algorithm uses the channel correlation in the frequency domain to greatly reduce the computation complexity and the number of required samples. The OFDM-MIMO structure with pilot insertion eliminates the ambiguity of blind identification. Analysis of the estimation accuracy and the subcarrier channel capacity shows that the normalized mean square error (NMSE) of the algorithm is about 10~(-2) for a 2-input-2-output OFDM-MIMO system with 1 024 subcarriers and that the blind algorithm helps the system to achieve more capacity than that of training based systems in fast-varying channels.