  The Fifth Generation (5G) New Radio (NR) does not support data transmission
during the random access (RA) procedures, which results in unnecessary control
signalling overhead and power consumption, especially for small data
transmission. Motivated by this, we propose two new RA schemes based on the
existing grant-based (4-step) and grant-free (2-step B) RA schemes, which are
NR Early Data Transmission (NR EDT) and 2-step A RA schemes, with the aim to
enable data transmission during RA procedures in Radio Resource Control (RRC)
Inactive state. To compare our proposed schemes with the benchmark schemes, we
provide a spatio-temporal analytical framework to evaluate the RA schemes,
which jointly models the preamble detection, Physical Uplink Shared Channel
(PUSCH) decoding, and data transmission procedures. Based on this analytical
model, we derive the analytical expressions for the overall packet transmission
success probability of four RA schemes in each time slot. We also derive the
throughput and the average energy consumption for a successful packet
transmission of each scheme. Our results show that the 2-step A and 2-step B RA
schemes provide the highest overall packet transmission success probability,
the 2-step A RA scheme provides the lowest average energy consumption in low
device intensity scenario, and 2-step B RA provides the lowest average energy
consumption in high device intensity scenario.
