An Enhanced Random Access With Distributed Pilot Orthogonalization for Cellular IoT Networks

Abstract

In this paper, we propose an enhanced random access (RA) with a distributed pilot orthogonalization (ERA-DPO) for mitigating packet collisions in Step3 during the RA procedure in cellular internet-of-things (IoT) networks. Even though each IoT device experiences a preamble collision in Step1, it can avoid the packet collision in Step3 by differentiating uplink pilot with the proposed technique, which provides an opportunity for the collided packets to be separated in spatial domain by multiple receive antennas. We also mathematically analyze the performance of the proposed scheme in terms of packet collision probability, throughput, and resource efficiency, based on a Markov chain model. Simulation results reveal that the proposed scheme significantly reduces the packet collision probability and increases resource efficiency compared to the conventional scheme.