SU-MIMO = Single User MIMO It is the most common form of MIMO. Each user is served by only one BS and it occupies the resource exclusively, including time, frequency. It can be applied in the uplink or downlink. But it is generally applied only in DL. The UE can easily have 2 antennas in … Read more
The UE is requested to send either periodic or a periodic reports concerning • Rank indication (RI) Reports are applicable for closed- and open-loop spatial multiplexing. In case of open-loop TRI=1 corresponds to transmit diversity and TRI>1 to large delay CDD. • Precoding matrix indicator (PMI) PMI reporting is relevant for spatial multiplexing (open- and … Read more
CSI feedback allows downlink transmission to be adaptively optimized based on the instantaneous DL channel, so that closed loop beamforming and adaptive link adaptation can be enabled to optimize the system performance. The DL reference signal used for CSI measurement is different in Rel-8 and Rel-10. In Rel-8, CSI measurement is based on CRS, which … Read more