Detecting the Number of Transmit Antennas with Unauthorized or Cognitive Receivers in MIMO Systems

In this work we consider one of the challenges facing unauthorized receivers and cognitive radios since the appearance of MIMO system, which is detecting the number of transmit antennas. To achieves this goal, we present a detector based on objective information theoretic criteria (the celebrated AIC and MDL estimators). Numerical results derived for an ideal BLAST-like transmission demonstrate good performance already for mild SNR conditions and majority decision based on rather few independent measurements.