Code combination for blind channel estimation in general MIMO-STBC systems
EURASIP Journal on Advances in Signal Processing
Blind channel estimation in orthogonally coded MIMO-OFDM systems: a semidefinite relaxation approach
IEEE Transactions on Signal Processing
Blind recognition of linear space-time block codes: a likelihood-based approach
IEEE Transactions on Signal Processing
IEEE Transactions on Signal Processing
Training sequence design for discriminatory channel estimation in wireless MIMO systems
IEEE Transactions on Signal Processing
| Hi-index | 754.85 |
In this paper, the conditions for blind identifiability from second-order statistics (SOS) of multiple-input multiple-output (MIMO) channels under orthogonal space-time block coded (OSTBC) transmissions are studied. The main contribution of the paper consists in the proof that, assuming more than one receive antenna, any OSTBC with a transmission rate higher than a given threshold, which is inversely proportional to the number of transmit antennas, permits the blind identification of the MIMO channel from SOS. Additionally, it has been proven that any real OSTBC with an odd number of transmit antennas is identifiable, and that any OSTBC transmitting an odd number of real symbols permits the blind identification of the MIMO channel regardless of the number of receive antennas, which extends previous identifiability results and suggests that any nonidentifiable OSTBC can be made identifiable by slightly reducing its code rate. The implications of these theoretical results include the explanation of previous simulation examples and, from a practical point of view, they show that the only nonidentifiable OSTBCs with practical interest are the Alamouti codes and the real square orthogonal design with four transmit antennas. Simulation examples and further discussion are also provided.