Abstract: This paper investigates a novel scheme combining spatial multiplexing with beamforming in spite of the contradictive requirement of antenna element spacing. The proposed scheme combines spatial multiplexing with beamforming of space-time block coding, which has the advantages of both techniques. The diversity gain is achieved by beamforming, and the multiplexing gain by spatial multiplexing according to different antenna array groups. The performance analysis and simulation results of the single antena array are shown to be dependent on the DOA and AS. However, the multiple antenna array is shown to have a stable performance independent of DOA and AS. Simulation results indicate that multiple antenna array can improve performnace by 12dB compared with the single antenna arrays when the direction of arrival is 0 angles and the angular spread is 50 angles. The performance will be improved obviously if the angular spread becomes smaller.

Key words: space-time block coding(STBC), eigen-beamforming, antenna arrays, direction of arrival(DOA), angular spread(AS)