Joint MIMO channel tracking and symbol decoding for orthogonal space-time block codes

In this paper, we consider the problem of channel tracking for a MIMO communication system which uses orthogonal space-time block codes (OSTBCs) as the underlying space-time coding scheme. We propose a two-step tracking algorithm. As the first step, Kalman filtering is used to obtain an initial channel estimate for the current block based on the channel estimates obtained for previous blocks. Then, in the second step, the so-obtained initial channel estimate is refined using a decision-directed iterative method. We show that due to specific properties of OSTBCs, both the Kalman filter and the decision-directed algorithm can be significantly simplified. Simulation results show that the proposed tracking method can provide accurate enough channel estimates.