| Summary: | 碩士 === 國立中央大學 === 通訊工程學系 === 105 === In this paper, we propose a non-orthogonal multiple access systems based on multiuser beamforming (BF-NOMA) and multicarrier systems on downlink. In BF-NOMA systems, we can use a method for user grouping and power allocation to enhance the system sum capacity. The user grouping method, we divided two users into a group with correlation. In addition, a single BF vector is be shared by two users in a group, so that we can support more users than OMA sysyem. One user is strong user and the other is weak user in the same group. We need to solve the interference from the other beam and other user in the same beam in order to improve the system sum capacity. Successive interference cancellation is a technique to eliminate the interference derived from the weak user. In this system, we use multi-carrier instead of single-carrier and it can improve bandwidth efficiency. We proposed a subcarrier allocation scheme between each user, so that enhance the sum capacity in BF-NOMA systems. We ensure that all assigned subcarriers transmit data to the strong user in the system, but it is not possible that the subcarrier is assigned to the weak user individually. We discuss how the strong and weak users do resource allocation under conditions of different subcarriers and sum rate. The simulation results verify that the proposed subcarrier allocation scheme in BF-NOMA improves the sum capacity, compared to the conventional BF-NOMA.
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