Читать книгу Spatial Multidimensional Cooperative Transmission Theories And Key Technologies - Lin Bai - Страница 48

As mentioned above, in order to obtain a sufficiently high transmission rate, we can install multiple antennas on both the transmitter and the receiver to improve the spectral efficiency. The corresponding multi-antenna system is also called the MIMO system. When multiple antennas are used at both ends of the link, in addition to improving diversity gain and array gain, the system’s throughput can also be increased by the spatial multiplexing capability of the MIMO channel. However, it must be pointed out that it is impossible to maximize spatial multiplexing capability and diversity gain simultaneously. Besides, the array gain in the Rayleigh channel is also limited, which is smaller than M_RM_T. In the following, the MIMO technologies will be classified according to the understanding of the channel information by the transmitter.