In cooperative MIMO relaying systems, channel estimation involves estimating channel matrices at the receiver and/or relay. Starting from this setup and its generalizations (multiple relays, three-hop, and multi-hop cases), tensor decompositions have been largely applied to solve the channel estimation and the joint channel-symbol estimation problems for tensor-coded MIMO relaying systems.
These tensor-based approaches leverage the multilinear nature of MIMO relaying channels, providing structured methods for channel estimation that reduce the need for pilot signals while enabling semi-blind decoding techniques.