Analyzing Novel Grant-Based and Grant-Free Access Schemes for Small Data Transmission

Fifth Generation (5G) New Radio (NR) does not support data transmission during random access (RA) procedures, which results in unnecessary control signalling overhead and power consumption, especially for small (SDT). Motivated by this, 3GPP has proposed 4/2-step SDT RA schemes based on the existing grant-based (4-step) grant-free (2-step) schemes, with aim to enable procedures Resource Control (RRC) Inactive state. To compare benchmark we provide a spatio-temporal analytical framework evaluate jointly models preamble detection, Physical Uplink Shared Channel (PUSCH) decoding, procedures. Based this model, derive expressions overall packet success probability average throughput each RACH attempt. We also energy consumption Our show that 2-step scheme provides highest probability, lowest but performance gain decreases increase of device intensity.