Preamble Parallelization Based Random Access with Colliding Preamble Reuse for Industrial IoT.

In the context of the industrial Internet of Things (IIoT), accommodating massive connectivity presents significant challenges for random access (RA) networks, primarily due to scalability and diverse quality-of-service (QoS) requirements, resulting in severe preamble collisions. We propose a novel Preamble Parallelization Based Random Access with Colliding Preamble Reuse (PP-RACPR) scheme applicable to the RA procedure. Our method enhances the RA procedure by allowing machine-type communication devices (MTCDs) to transmit multiple preambles in parallel during the initial step of the RA procedure, increasing the successful access rate. Additionally, MTCDs are empowered to reuse part of colliding preambles by identifying them earlier in the process, thereby improving the preamble utilization ratio (PAUR) for the RA network. Finally, we conduct a comprehensive mathematical analysis of the proposed scheme, focusing on the system PAUR, and corroborate our analytical framework through extensive simulations, demonstrating its feasibility and efficacy in supporting massive MTCDs and mitigating preamble collisions.