A subspace based blind and semi-blind channel identification method for OFDM systems

Abstract

A new subspace method performing the blind and semi-blind identification of the transmission channel suited to multicarrier systems with cyclic prefix (OFDM) is proposed in this paper. This technique has the advantage to preserve the classical OFDM emitter structure based on a cyclic prefix insertion. Therefore it applies to all existing standardized multicarrier systems (DAB, ADSL, etc.) and does not prevent the use of the classical very simple equalization scheme. Moreover the method detailed provides an unbiased channel estimation and is robust to channel order overdetermination provided that the channel frequency response has no zeroes located on a subcarrier.