This letter considers a legacy massive multiple-input multiple-output (MIMO) network, in which spatial beams have been preconfigured for near-field users, and proposes to use the non-orthogonal multiple access (NOMA) principle to serve additional far-field users by exploiting the spatial beams preconfigured for the legacy near-field users. Our results reveal that the coexistence between near-field and far-field communications can be effectively supported via NOMA, and that the performance of NOMA-assisted massive MIMO can be efficiently improved by increasing the number of antennas at the base station.

翻译：本文针对已有大规模多输入多输出（MIMO）网络中空间波束已为近场用户预先配置的场景，提出利用非正交多址接入（NOMA）原理，通过复用现有近场用户的预配置空间波束为额外远场用户提供服务。研究结果表明，基于NOMA能够有效支持近场与远场通信的共存，且通过增加基站天线数可有效提升NOMA辅助大规模MIMO系统的性能。