Two-Dimension Adaptive Spectral Efficiency for SC-FDMA Systems

Abstract

We propose a two-dimension adaptive spectral efficiency scheme for a new-designed single-carrier frequency division multiple access (SC-FDMA) system by flexible reference signal (RS) and data multiplexing for each user. Based on Doppler spread, each user first determines the number of SC-FDMA symbols that bear RS in a time slot, and each of such SC-FDMA symbols, based on bandwidth allocation, then serves to estimate a shortened time-domain channel impulse response (CIR) as well as bear data. The proposed design significantly outperforms the channel estimation (CE) case of Third Generation Partnership Project (3GPP) Long Term Evolution (LTE) uplink in terms of spectral efficiency at a high Doppler spread.