Channel Estimation of MIMO Relay System Using Cascaded TUCKER Model

A channel estimation method based on the spacetime tensor coding scheme is proposed for the one-way three-hop MIMO relay system. The method utilizes tensor coding at the source node and the two relay nodes, constructs the cascaded TUCKER model to reduce the dimension of the higher order received signal according to the cascade characteristic of signal transmission model, and derives the independent matrix decomposition form of unknown matrix. The semi-blind channel estimation is performed by using alternating least squares algorithms at the destination node, and the identifiability conditions and uniqueness of the algorithm are analyzed. Compared with traditional PARATUCK2 and Nested PARAFAC models, the cascaded TUCKER model makes full use of advantage of tensor coding which effectively improves the channel estimation accuracy. The simulation results show that the Normalized Mean Square Error can be decreased by one order of magnitude when $E_{b}/N_{0}$ is 10dB relative to the traditional semi-blind method.