Optimal pilot tones for MIMO interleaved OFDM systems

This paper describes a channel estimation scheme for MIMO interleaved orthogonal frequency division multiplexing (IOFDM) systems. The mean square error (MSE) of the proposed scheme is derived, and for the MSE of the channel estimates to be minimized, it is shown in this paper that the pilot tones have to be equispaced in frequency, equipowered, with the entire power being allotted to the pilot tones in one of the P data blocks of an IOFDM block, and the tones in the corresponding positions in the remaining P-1 data blocks being equal to zero. Through simulations, a comparison is made between the proposed training scheme for MIMO-IOFDM and other training sequences, and also between the proposed training scheme and the existing schemes which estimate the channel over P consecutive blocks.