Analysis of Random Access in NB-IoT Networks With Three Coverage Enhancement Groups: A Stochastic Geometry Approach

NarrowBand-Internet of Things (NB-IoT) is a new 3GPP radio access technology designed to provide better coverage for Low Power Wide Area (LPWA) networks. To reliable connections with extended coverage, repetition transmission scheme and up three Coverage Enhancement (CE) groups are introduced into NB-IoT during both Random Access CHannel (RACH) procedure data procedure, where each CE group configured different values resources. characterize the RACH performance network groups, this paper develops novel traffic-aware spatio-temporal model analyze success probability, preamble outage collision events jointly determine traffic evolution probability. Based on analytical model, we derive expression probability randomly chosen IoT device in over multiple time slots schemes, including baseline, back-off (BO), class barring (ACB), hybrid ACB BO schemes (ACB&BO). Our results have shown that probabilities devices outperform single but not all which affected by choice categorizing parameters.This mathematical framework can be applied evaluate users other networks spatial separations.