Non-orthogonal Random Access for Massive Machine Type Communications

Machine-type communication (MTC) plays a crucial role in the success of the internet of things (IoT) paradigm. It enables MTC devices (MTCDs) to communicate with each other seamlessly and efficiently, leading to improved automation, productivity, and user experience. However, the massive connections of these devices across cellular networks cause congestion and network overload due to collisions during the random access (RA) process. This results in delays, an increase in the amount of energy consumed by MTCDs, and a proportional decrease in efficiency. Several techniques, such as congestion control mechanisms and a non-orthogonal random access scheme (NORA), have been suggested to mitigate these challenges. In this paper, we propose a cluster-based NORA scheme (CNORA) as a solution to the issues of congestion and network overload. Clustering the MTCDs and utilizing NORA to limit the number of collisions that occur during the RA process allows us to achieve our goal of decreasing the total number of access requests coming from the MTCD with reduced energy consumption. Our proposed scheme shows improvements in the average access delay and RA efficiency.