Estimation of transmit-antenna number with different space–frequency transmission schemes for MIMO-OFDM systems

A hypothesis testing based algorithm is proposed to estimate the transmit-antenna number with different space-frequency transmission schemes for multiple-input multiple-output orthogonal frequency division multiplexing (MIMO-OFDM) systems. The ranks of received sample covariance matrices composed by every two adjacent subcarriers can be estimated by utilising the statistical property of the largest noise eigenvalue. With a series of the estimated values of the ranks, the number of transmit antennas is determined by a decision mechanism, which is designed based on the frequencies of the rank values. Simulations demonstrate that the proposed algorithm performs well without the prior knowledge of the space-frequency transmission scheme.