On the impact of imperfect channel knowledge on the performance of orthogonal STBCs

We derive two theorems that enable us to determine the bit error rate performance of orthogonal space-time block codes in an analytical way if the channel impulse response is measured by pilot based maximum likelihood estimation at the receiver. The first one gives an exact solution, but requires numerical integration. The second one provides an approximation that is improving with increasing number of antennas. The analysis is based on a real-valued transmission model which allows for a representation of orthogonal space-time block codes as linear spreading matrices. That means, encoding and decoding the space-time block code is carried out by a single matrix multiplication at the transmitter and the receiver, respectively.