Suboptimal precoding vector selection scheme combined with frequency domain scheduling for closed-loop MIMO transmission in LTE-Advanced uplink

This paper proposes suboptimal precoding vector (PV) selection schemes combined with frequency domain scheduling when closed-loop MIMO precoding is adopted in the LTE (Long-Term Evolution)-Advanced uplink based on single carrier-frequency division multiple access (SC-FDMA) radio access. In the proposed schemes, frequency domain channel-dependent scheduling is performed based on a tentatively selected PV for each subband, and then a suitable PV is selected that is common to the contiguously allocated resource blocks in the frequency domain for each UE in order to achieve the single carrier property, i.e., a low peak-to-average power ratio (PAPR). System-level simulation results show that by employing the proposed scheme, the sector throughput performance is increased by 1.6% and 2.3% compared to the conventional scheme in the case of 2-by-2 and 4-by-2 MIMO, respectively. Furthermore, we clarify that the losses in the achievable sector throughput by using the proposed scheme are only 0.9% and 2.4% for 2-by-2 and 4-by-2 MIMO, respectively, compared to the ideal condition using frequency selective precoding.