MSPA: Multislot Pilot Allocation Random Access Protocol for mMTC-Enabled IoT System

To provide massive connectivity in massive machine-type communications (mMTCs) for the Internet of Things (IoT) system, a novel grant free random access protocol, called multislot pilot allocation (MSPA) is proposed in this article, where the user equipments (UEs) are permitted to jointly transmit randomly chosen pilot sequences along with their data packets over multislot to resolve intracell pilot collision. In addition, by utilizing the belief propagation tool for the MSPA protocol, the closed-form expressions to the access failure probability (AFP) and system throughput in a finite length regime are derived, which are highly desired for practical-interest mMTC network. Further, a guideline for certain mMTC scenarios that target urgent serving requirement UEs is also proposed to minimize the access latency and maximize the system throughput under diverse AFP constraints. Finally, the parametrical analysis of the MSPA protocol is given by theoretical proof and simulation verification, which shed light on the advantages of our MSPA protocol over the existing protocols in terms of achieving high throughput and shortening the access latency.