A novel orthogonal space time block code (OSTBC) that is capable of extracting a diversity order of two via a single RF frontend is proposed in this paper. The scheme is implemented using a practical antenna system of two transmit antennas connected to a common ground. An orthogonal block of two real (non-complex) signals is transmitted over a duration of two symbol periods by exciting one antenna every symbol period while exciting the other parasitically by the field of the active one. A switched-antenna system similar to the one reported in [10] can be used for simultaneously driving and switching the antenna elements. Besides the orthogonality of the signals, the array far-field is a linear mixture of two eigenpatterns onto which the BPSK signals are mapped, hence independent fading among the signals is almost always guaranteed.
展开▼
