Flexible and efficient resource allocation method based on the number of transmit antennas in hybrid multiple access scheme using NOMA and OMA

Abstract

Non-orthogonal multiple access (NOMA), which multiplexes users in the power domain, degrades performance when the channel gain difference between users is small. To mitigate the performance degradation specific to NOMA, a hybrid multiple access scheme that simultaneously utilizes NOMA and orthogonal multiple access (OMA) is effective. So far, we have proposed a resource allocation method that allows for flexible settings of the NOMA power allocation ratios and OMA bandwidths and selects the optimal resource pattern based on the users’ channel conditions and desired traffic volumes. In this study, we propose a resource pattern reduction method to reduce the cost of resource allocation in the conventional method by focusing on the applicability of NOMA and OMA, which depend on the number of transmit antennas. Furthermore, to clarify the effectiveness of the proposed method, we compared it with a conventional method that performs high-granularity resource allocation for different power ratios and bandwidths in terms of the system throughput.