Resolution of Near-Field Beamforming and Its Impact on NOMA

The resolution of near-field beamforming is an important metric to measure how effectively users with different locations can be distinguished. This letter identifies the condition under which the resolution of near-field beamforming is not perfect. This imperfect resolution means that a legacy user’s preconfigured near-field beam can be still useful to other users, which motivates the application of non-orthogonal multiple access (NOMA). Both the analytical and simulation results are presented to demonstrate that indeed those near-field beams preconfigured for legacy users can be used to serve additional NOMA users effectively, which improves the overall system throughput and connectivity.