LAUSR

Narrowband Internet of Things (NB-IoT) is a Quasi-5G technology that will provide coverage for massive number of low-power consumption applications. Hence, the potential massive random access (RA) users call for a new RA scheme. In this paper, based on the key ideas of non-orthogonal multiple access and successive interference cancellation, the NB-IoT non-orthogonal random access (NB-NORA) scheme has been proposed to provide a more effective access performance for NB-IoT system. Further, the RA preamble (MSG1) transmission collision probability and initial layer 3 message (MSG3) outage performances are analyzed based on stochastic geometry, which is compared with the traditional NB-IoT orthogonal random access (NB-ORA) scheme. Simulation results show that the maximum throughput of MSG1 within NB-NORA scheme is double that within NB-ORA scheme, and the successful RA probability of NB-NORA is increased by about 75%.