System Performance of Clustered DFT-S-OFDM Considering Maximum Allowable Transmit Power

Support of non-contiguous frequency resource allocation (FRA) based on clustered discrete Fourier transform-spread orthogonal frequency division multiplexing (clustered DFT-S-OFDM) is considered a key element of LTE-Advanced uplink to enhance the spectrum efficiency via an enhanced frequency domain scheduling. However, reduction of out-of-band emissions due to multiple clusters is a critical issue for clustered DFT-S-OFDM in an actual system. This paper verifies the system performance gain of clustered DFT-S-OFDM using power control (PC) with maximum power reduction (MPR) for suppression of out-of-band emissions, under realistic assumptions, including channel quality measurement error and power setting error. Simulation results show that the clustered DFT-S-OFDM improves the average throughput over DFT-S-OFDM, even with PC with MPR, but suffers some degradation due to the large fixed MPR. By applying a novel PC with autonomously adjusted MPR that depends on the separation of the clusters, no degradation of the performance gain is observed while satisfying the spectrum emission requirements.