A Sufficient Condition for Blind Identifiability of MIMO-OSTBC Channels Based on Second Order Statistics
In this paper the conditions for blind identifiability of Multiple-Input Multiple-Output (MIMO) channels under Orthogonal Space-Time Block Coded (OSTBC) transmissions are studied. Specifically the authors prove that, regardless of the number of receive antennas, any real or complex OSTBC transmitting an odd number of real symbols permits the blind identification of the MIMO channel by only exploiting the Second Order Statistics (SOS) of the received signal. This result extends to complex OSTBCs and provides an alternative proof of an identifiability theorem previously proved only for real OSTBCs. Furthermore, this sufficient condition suggests that any non-identifiable OSTBC can be made identifiable simply by not transmitting one real symbol of each block (either the real or imaginary part of a symbol in the case of complex OSTBCs).