A study of beamforming system combined with space-time block coding in mobile communications

Abstract

The current work develops an efficient scheme to be used for the downlink transmission in mobile communications, using transmit diversity or beamforming. In this thesis, we consider downlink beamforming system combining space-time block encoder in order to improve the performance. The simulated results are obtained to examine the effects of the number of transmit antennas, the order of space-time block coding, and angular spreads. Simulation results show that the better performance is realized when the beamforming system is combined with space-time block coding. Accordingly, we can get the diversity effect from space-time block coding and the beamforming gain from array antennas, simultaneously, by combining beamforming system with space-time block encoder. And another interesting result is the effect of angular spread. We can observe the improved performance as angular spread increases up to some threshold. This is due to the increased diversity effect as a result of the decorrelation of the fading among the antenna elements from angular spread.