LTE Advanced: 3GPP Solution for IMT-Advanced

7.6 Conclusions

In this chapter, we have covered the LTE uplink MIMO principles as defined in 3GPP Release 10 specifications as well as the resulting performance. The use of uplink SU-MIMO allows improving the peak data rate and performance but the price to pay is the need to use of two or more uplink transmitter RF chains, including use of more than one power amplifier and UE transmit antennas. The implementation is made a bit easier by using such precode design which retains the signal waveform properties (cubic metric) to avoid additional power reduction. In addition to the capacity the theoretical uplink peak data rate per 20 MHz carrier is increased up to 300 Mbps. For Release 11 there is no further work ongoing on the uplink MIMO enhancements but as part of the work on the Co-ordinated MultiPoint (CoMP) work item, the uplink aspects of the multi-site reception (and possible related feedback) are being addressed for Release 11 as covered in Chapter 13.