Training signal design for MIMO channel estimation with correlated disturbance

This paper studies minimum mean square error (MMSE)-based training signal design for MIMO channel estimation with correlated disturbance (i.e., interference plus noise). First, we consider training signal design for Kronecker-structured MIMO channel estimation where both channel and disturbance are assumed in Kronecker structures. We prove the optimal training sequence structure for arbitrarily Kronecker-structured MIMO channel estimation. Using the optimal training sequence structure, we show that the MSE minimization problem can be globally solved. Second, we consider the training signal design problem in the case of general channel and disturbance model (i.e., without Kronecker structure assumption). We propose a simple iterative algorithm based on block coordinate descent method which can keep the MSE nonincreasing at each iteration. Finally, simulation results indicate good performance of the proposed iterative algorithm by comparing with the optimal training signal design method.