Enumeration of Base Station Antennas in a Cognitive Receiver by Exploiting Pilot Patterns

This letter deals with the identification of the number of transmitting antennas at a base station. This estimation is achieved by exploiting the orthogonality between the pilot patterns from each transmitting antenna. This orthogonality allows us to use multi-hypothesis testing in order to enumerate the number of transmitting antennas using only one antenna at the receiver. As a side product, the proposed algorithm allows us to estimate the channel gains from all transmitting antennas and the noise variance.