16.23.4.1 Waveform, numerology, time and frequency domain structure

The R2D transmission is a DFT-s-OFDM-based OOK waveform with subcarrier spacing Δf=15∙103 Hz and normal cyclic prefix. The R2D transmission in each OFDM symbol is described by a number of resource blocks, NRBR2D, and one resource block consists of 12 consecutive subcarriers. In each OFDM symbol, there are a number of chips to which modulated symbols are mapped. For in-band operation, the starting position of a A-IoT R2D transmission is aligned in time with the starting position of an NR OFDM symbol.

The D2R transmission is described by a set of chips to which modulated symbols are mapped, and based on backscattering on a carrier wave. The carrier wave is a single-tone sinusoid signal.