Dynamic Pilot Allocation Channel Estimation with Spatial Multiplexing for MIMO-OFDM Systems

In this paper, we investigate a dynamic pilot allocation algorithm for Discrete Fourier Transform (DFT)-based channel estimation in MIMO-OFDM systems, which employs feedback to adapt pilot locations to mobile channels for different receivers (ZF-linear, ZF-SIC, MMSE-linear, MMSE-SIC). The pilot allocation is dynamically controlled by feedback of the pilot allocation index so to optimize SER performance. Furthermore, mathematical expressions of the instantaneous signal to interference and noise ratio (SINR) in the presence of channel estimation error for different receivers are derived to obtain the error probabilities of data subcarriers through an approximate error probability function for MPSK modulation. The pilot locations are based on these error probabilities to avoid data symbols transmitted over these subcarriers with high error probabilities instead of pilots over them. Simulation results are provided to illustrate the performance gains achieved with these receivers by this dynamic pilot allocation.