Abstract
The disclosure provides a user selection method for non-orthogonal multiple access (NOMA) systems and a base station thereof. The method includes: (1) initializing the cluster-partition parameter i to be 2; (2) dividing N user devices into i clusters; (3) selecting a reference device from each of the i clusters to form a reference cluster; (4) performing a power allocation algorithm for the reference cluster to calculate a power allocation factor for each of the reference devices; (5) determining whether each of the reference devices with the calculated power allocation factors meets a set of constraints: if all of the reference devices meet the set of constraints, increasing the value of i by 1 and then going back to step (2); if any one of the reference devices does not meet the set of constraints and i is not equal to 2, performing NOMA transmission for the reference cluster.