Two-step Random Access with Collision Resolution Queueing for Cellular IoT networks

Recently, 2-step random access (RA) has been a preferred scheme through which an IoT device transmits data in cellular Internet of Things (IoT) networks for Machine-Type Communications (MTC). In contrast to 4-way handshake that was originally needed before data transmission, in 2-step RA the signalling is reduced and there is no need of connection establishment for data transmission. Overall, the latter approach reduces also latency. In this work, collision resolution queueing (CRQ) algorithm is employed in 2-step RA scheme in order to manage preamble collisions. Simulation results reveal improvement on system performance when a large number of IoT devices exist in the network, or the offered load is high.