LTE uplink system based on universal timedomain windowed DFTs-OFDM

Abstract

For the 5G systems, new uplink waveforms enabling low peak-to-average power ratio (PAPR) and low out-of-band emission (OOBE) are required to enhance spectrum efficiency while maintaining power efficiency of mobile terminals. Discrete Fourier transform-spread orthogonal frequency division multiplexing (DFTs-OFDM) is extensively used as an uplink multiple access scheme for existing Long Term Evolution (LTE) and LTE-Advanced systems. Despite lower PAPR of DFTs-OFDM compared to conventional OFDM, its high OOBE limits the spectral availability in adjacent channels. Universal time-domain windowing (UTW) is expected to significantly reduce OOBE, while it is necessary to demonstrate its practicality with a comprehensive evaluation including the communication quality. In this paper, we apply the UTW to the 5 MHz LTE uplink system based on DFTs-OFDM (UTW-DFTs-OFDM) and simulate its performance in respect to OOBE, PAPR, and block error rate (BLER) under the frequency selective fading environment. In addition, we propose new receiver architecture to improve the communication quality and clarify the trade-off between OOBE reduction and the communication quality. The simulation results indicate that UTW-DFTs-OFDM significantly reduces the OOBE by applying a long time-domain window in excess of the CP length with maintaining sufficient communication quality.