Hybrid beamforming: reduced eigen beamforming on beam signals

A hybrid beamforming technique for multiple antenna receivers is introduced. It is a combination of a simple fixed beam method and the adaptive eigen beamforming algorithm. This two-stage solution allows for a user-specific scalable trade-off between performance and complexity, depending on the interference scenario. Furthermore, the dimensions of the eigen beamforming stage can be reduced with only slight performance degradation. The hybrid scheme is compared with the stand-alone algorithms in different two-user scenarios under ideal as well as under more realistic assumptions. It is shown, that in many scenarios the fixed beamforming stage is sufficient. In more severe interference scenarios, the hybrid techniques approach the performance of the eigen beamformer with less complexity