This invention provides a joint user clustering and power allocation method and a base station using the same. They are applicable to cooperative non-orthogonal multiple access (NOMA) systems. The method includes: sorting user equipment devices (UEs) according to the channel gains between the base station and the UEs, and then establishing a strong user candidate group of UEs and a weak user candidate group of UEs; pairing each of the UEs in the strong user candidate group with each of the UEs in the weak user candidate group so as to divide the UEs into clusters, where the power allocation coefficients for each pair of UEs are also calculated during the paring process; and transmitting messages to the UEs based on the calculated power allocation coefficients of the clusters. |