Article ID: 2018XBL0083
Nowadays, multiple-input multiple-output (MIMO) transmission becomes an essential technology for wireless communication systems. Because the MIMO transmission performance heavily depends on the propagation channel characteristics, those channel parameters have been investigated through various radio measurements. In this paper, we propose a parameter estimation refinement method based on the nonlinear conjugate gradient (NLCG) approach. In our proposal, the accurate propagation parameters are obtained with a few iterations without falling into the local maximum points of the likelihood function. The proposed method was evaluated through a computer simulation, and the results showed that the residual signal power ratio (RSPR) of the channel reconstructed was improved by approximately 17% compared with the space-alternating generalized expectation-maximization (SAGE) algorithm. The proposed method is expected to be utilized for channel measurements in the future work.