| dc.description.abstract | The paper investigates the feature and performance evaluation of transmission system based on MU-MIMO strategy. We consider number of active users in coverage area, user mobility and environments SNR. MU-MIMO gained numerous attention of researchers because of the spatial efficiency, multi user diversity gain and fit to transmit in good SNR environments. Moreover, it allows the spatial multiplexing gain at the BS to be obtained without the need for multiple antenna terminals, while power saving and cost is kept on the infrastructure side. In BS antenna configuration, widely spaced antennas reduce the spatial correlation and usually result in good SU-MIMO performance but MU-MIMO is found to perform particularly well in highly correlated antenna setups, which is a promising candidate for practical deployment. Unfortunately, MU-MIMO is not an almighty solution. Spatial efficiency accompanies more processing in interuser interference problem. Multi user diversity gain represents the performance degradation with a decreasing number of users and it will not performs good in low SNR environments. Furthermore, multibeam beamforming demand more accurate CSI, it cause high decadence in high channel speed. We propose a downlink transmission scheduling structure considering QoS scheduling, grouping performance prediction, MIMO mode switching and grouping optimization. In our simulation, we followed LTE SPEC to evaluate the performance and superior environments of different transmission mode and demonstrate appropriate transmission mode switching point. Furthermore, we set up LTE-A antenna configurations and showing the switching mechanism in throughput performance affect is direct and powerful. | en_US |