Space-Time Spreading MIMO System Using Canonical Precoding Tensor Model

We consider a multiple input multiple output (MIMO) antenna system based on Space-Time Spreading (STS), where multiple data streams are preceded across space and time dimensions using multiple spreading codes. We propose a canonical precoding structure based on a CONstrained FACtor (CONFAC) decomposition of a tensor. The precoder tensor is decomposed as a function of three canonical (constraint) matrices that define the allocation of data streams and spreading codes to transmit antennas. Different STS schemes can be derived with the proposed modeling framework by simply adjusting the canonical precoder structure. The uniqueness property of the CONFAC decomposition allows a blind joint detection/channel estimation with the knowledge or not of the spreading codes.