Forward Link Beamforming Performances of FDD-SDMA Packet Cellular Testbed System

We carried out field trials of the developed FDD-SDMA packet cellular testbed system and demonstrated the effectiveness of the proposed forward link beamforming algorithm. Our forward link beamforming algorithm use not only unidirectional access terminal estimation but also angular spread estimation that is the proposed method and available to extract angular spread characteristics from a correlation matrix accumulated with reverse link signals through eigen decomposition. Moreover, the proposed beamforming algorithm is equipped with forward link array antenna weighting vector normalization to prevent from demodulation and channel estimation errors with omni-beamformed pilot channel. During the field trials, we confirmed that the throughput performance per access point of the proposed forward link beamforming algorithm exceeded that of the conventional beam-null forming algorithm with only unidirectional access terminal estimation and were convinced of the effectiveness of the proposed algorithm in a real field environment with angular spread