Signal Selection Considerations for MIMO with One Active Transmit Antenna

This article discusses the issue of signal selection for a multiple-input multiple-output (MIMO) system, when only one of several antennas on the transmitting side is active. To increase the efficiency, in the presented system, constellations of the same size, but of different types, are defined for each transmitting antenna. They are called partner constellations. In such a scheme, the selection of partner constellations is important, and this process is implemented in terms of the minimum squared Euclidean distance between them. To evaluate the results, a computer simulation based on pairs of binary phase-modulated signals with different distance properties and MIMO with one receiving and two transmittting antennas, of which only one is active, is used. The communication channel is represented by additive white Gaussian noise and fading with a Nakagami distribution, which is due to the fact that the fading depth values are represented in a practically full spectrum.