LTE Advanced: 3GPP Solution for IMT-Advanced

7.5 Performance

In this section the benefits from the uplink MIMO operation are investigated, both theoretically and also based on the simulations. The following areas are improved:

• The uplink peak data rate achieved is increased with 16QAM modulation from 50 Mbps per 20 MHz to 100 Mbps and with 64QAM respectively from 75 Mbps to 150 Mbps in case of two antennas and further up to 300 Mbps with 4 stream MIMO transmission.
• The uplink capacity can be increased up to 40% compared to single antenna transmission, depending of the number of antennas used and on the correlation properties between the antennas.
• Further the MU-MIMO performance is improved as the flexibility of the pairing of users was improved.

Uplink throughput improvements from MU-MIMO and SU-MIMO are illustrated in Figure 7.9. In the results, the throughputs with and without MIMO operation are compared for the same number of receive antennas at the eNodeB. In the figure, gains from SU-MIMO as well as from MU-MIMO with Release 10 DM RS enhancements are shown. It can be noted that both SU-MIMO and MU-MIMO provide comparable gains on the cell capacity. Additionally, SU-MIMO precoding enhances considerably cell edge performance. Throughput gains from MIMO depend on a number of factors. For example, inter-cell interference rejection combining at eNodeB, which was not considered in here, typically reduces achievable MIMO gains. On other hand, MIMO gains for cell capacity are increased if the portion of UEs supporting 64QAM ...