Planar arrays hybrid beamforming for SDMA in millimeter wave applications

A radio-frequency and baseband beamforming scheme is presented for spatial division multiple access (SDMA) of 60 GHz applications using planar antenna arrays (PAA). PAA with phase shifters for each element antenna is partitioned into sub-blocks and each block or multiple blocks are applied to a user in the SDMA system. According to the analysis for the signal to interference plus noise ratios (SINRs) of the users in the SDMA system, it is shown that different users may have different permissible operating regions in order to maintain the SINRs for all users in the system. A procedure is proposed to identify the permissible operating regions for each user in the SDMA system. Based on these results, more flexible hybrid beamforming schemes are currently studied to support SDMA in a more efficient way for 60 GHz millimeter wave applications.