Iterative channel estimation with MIMO MMSE-turbo equalisation

Multiple-input-multiple-output (MIMO) systems promise to provide significant increases in system capacity for future wireless communication systems. However, realization of the highest potential capacity of a MIMO system will require the knowledge of the channel state information (CSI) in a system implementation. In this paper, an optimized adaptive scheme on several key parameters for iterative MIMO channel estimation is proposed, based on the study of different techniques for the MIMO channel estimation. This study includes the recursive least square (RLS) based adaptive approach iterative channel estimation combined with a MIMO minimum mean square error (MMSE) equalizer, by employing soft feedback information. The key parameters to be estimated are excess delay spread, adaptive forgetting factor, error variance of soft information, etc. Other important issues are also addressed on performance comparison with consideration of their trade-off on implementation complexity for possibly practical application.