Abstract
A method of joint clustering and precoding and a base station using the same are provided. They are applicable to non-orthogonal multiple access (NOMA) systems. The method includes: dividing four user equipments into the first cluster and the second clusters, each consisting of two user equipments; forming the first-cluster’s signal and the second-cluster’s signal for simultaneous transmission at the base station; establishing the first precoding set and the second precoding set for the first cluster and the second cluster, respectively, by using channel information between the base station and all the user equipments; selecting the first precoder from the first precoding set and the second precoder from the second precoding set; using the first precoder and the second precoder to precode the first-cluster’s signal and the second-cluster’s signal; and superposing the two precoded signals and broadcasting the resulting signal to the first cluster and the second cluster.