Grouping-Based Grant-Free Random Access Based on Statistical Distribution of User Rates

Multiple access technology is facing a great challenge posed by the upcoming massive Machine-Type Communication (mMTC). Traditional grant-based random access (RA) schemes are not competent to tackle the massive connectivity and small infrequent data packets of mMTC, because of the intolerable signalling overhead and delay. Grant-free random access joint with non-orthogonal multiple access (NOMA) may be suitable for the mMTC services as it...