Throughput Analysis and User Barring Design for Uplink NOMA-Enabled Random Access

Being able to accommodate multiple simultaneous transmissions on a single channel, non-orthogonal access (NOMA) appears as an attractive solution support massive machine type communication (mMTC) that faces number of devices competing the limited shared radio resources. In this paper, we first analytically study throughput performance NOMA-based random (RA), namely NOMA-RA. We show while increasing power levels in NOMA-RA leads further gain maximum throughput, growth is slower than linear. This due higher-power dominance characteristic power-domain NOMA known literature. explicitly quantify for very time paper. With our analytical model, verify advantage scheme by comparing with baseline multi-channel slotted ALOHA (MS-ALOHA), and without capture effect. Despite effect, four achieves over three times MS-ALOHA. However, results also reveal sensitivity load To cope potential bursty traffic mMTC scenarios, propose adaptive regulation through practical user barring algorithm. By estimating current based observable channel feedback, algorithm adaptively controls maintain optimal loading channels achieve throughput. When proposed applied, simulations demonstrate instantaneous always remains close confirming effectiveness regulation.