This study proposes a novel CDMA BLAST (Bell Labs layered space-time)
space-time code scheme used in forward link in a cellular CDMA system.
Both scrambling code and orthogonal spreading code are employed to specify
different transmit antennas and users, respectively. Since scrambling
codes use pseudo-noise sequences providing excellent quality of auto and
cross correlation proprieties, the proposed novel scheme can obtain considerable
improvement of performance without sacrificing the precious code resources.
The simulation results demonstrates the average BER of improved scheme
decrease 10 dB for (2, 2) system with 4 users when Eb/N0 = 7 dB.