Downlink Connection Density Maximization for NB-IoT Networks Using NOMA With Perfect and Partial CSI

We address the issue of maximizing number connected devices in a Narrowband Internet-of-Things (NB-IoT) network using nonorthogonal multiple access (NOMA) downlink. first propose an optimal joint subcarrier and power allocation strategy assuming perfect channel state information (CSI) called stratified device (SDA), which maximizes connectivity under data rate, power, bandwidth constraints. Then, we generalize maximization problem to case partial CSI, where only distance-dependent path-loss component gain is available at base station (BS). introduce novel framework stochastic optimization (SCO) framework. In this framework, heuristic improvement SDA, namely, SDA with excess (SDA-EP) algorithm for operation CSI. Furthermore, derive concave approximation (SCO-CA) near-optimal performance SCO given same amount Through computer simulations, show that SDA-EP SCO-CA outperform conventional NOMA OMA schemes presence CSI over wide range service scenarios.