Abstract
The invention provides a joint user grouping and precoding method and a base station using the method. The method is suitable for a non-orthogonal multiple access system. The method disclosed by the invention comprises the following steps: dividing four user devices into a first group and a second group; forming a first group signal and a second group signal, which are about to be sent at the same time, on a base station end; separately establishing a first precoder set and a second precoder set corresponding to the first group and the second group by using channel information among the base station and the user devices; separately selecting a first precoder and a second precoder from the first precoder set and the second precoder set; precoding the first group signal and the second group signal by using the first precoder and the second precoder; and superposing the two precoding results, and broadcasting and sending the superposed precoding result to the first group and the second group. The technology provided by the invention can effectively reduce the multiuser signal interference of an NOMA downlink system, and improve the transmission efficiency and the system capacity.