Performance Evaluation of Partially Clustered Access Scheme for Massive Machine Type Communications

Traffic congestion of a random access (RA) link can be resolved by clustering machine type communication devices (MTCDs) and using an aggregator. However, since a packet needs to wait in the aggregator, clustering may cause an additional delay. To solve this problem, this letter suggests a partially clustered access scheme (PCAS) in which direct-access MTCDs (dMTCDs) and clustered-access MTCDs (cMTCDs) are serviced together. We provided an analytical model and an energy consumption model for PCAS. Numerical and simulation results showed that clustering may improve a success ratio. Furthermore, the delay requirement of dMTCDs and the energy consumption requirement of cMTCDs can be guaranteed by using PCAS.