A comparative analysis of pilot placement schemes in frequency-selective fast fading MIMO channel

The problem of pilot placement for channel estimation in time-frequency-space lattice in MIMO- OFDM system under frequency-selective fast fading MIMO channel is addressed in this paper. Given the least square channel estimation algorithm and orthogonal pilot signal format design, four different pilot placement schemes are analyzed in a uniformed manner. The theoretical and simulated mean square errors of the schemes show that, the scheme of placing pilots on frequency-equal-spaced and time-shifted subcarriers has good performance and balanced complexity.