A subspace algorithm for guard interval based channel identification and source recovery requiring just two received blocks

Abstract

Blind channel identification techniques usually exploit a known property of the source symbols such as a statistical or finite alphabet property. Recently, a purely algebraic approach that relies on guard intervals (sequences of zeros equal or longer in length than the channel memory) inserted between transmitted blocks has been considered. It was proved that only two received blocks suffice for channel identification and source recovery. In this paper, the channel identification problem is approached from a z-domain perspective. It is shown that, in the z-domain, the channel is a common factor in all received blocks. (This fundamental property appears to have gone unnoticed in the literatur..