Dual-Core: Dual Collision Resolution for Massive Access in Cellular IoT Networks

The rapid expansion of Internet of Things (IoT) applications has led to significant access challenges for radio access networks, potentially causing bottlenecks and degrading service quality. This paper proposes Dual-Core, a novel dual collision resolution mechanism for the four-step random access (RA) procedure of 5G communication systems. Dual-Core integrates slotted ALOHA protocol for random access preamble (RAP) transmission and a custom splitting algorithm for bandwidth request message (Msg 3) transmissions, resolving collisions in both PRACH and PUSCH. Additionally, we introduce an online controlled access class barring (ACB) to maximize the throughput of Dual-Core, with the optimal ACB rate determined by our proposed analytical model. Numerical results demonstrate that the proposed Dual-Core significantly reduces service time compared to the conventional RA procedure operating at its optimal performance, while utilizing the same amount of PUSCH resources. Furthermore, when additional PUSCH resources are available, Dual-Core efficiently utilizes them to serve more devices, a capability that conventional systems lack.