This Manuscript exploits the diversity advantage and coding advantage of space time codes and the rate advantage of spatial multiplexing systems. A detailed analysis of the space time coding schemes such as space time block codes, CIODs, space time trellis codes, beamforming schemes and spatial multiplexing schemes using various processing algorithms are presented. The performance of the maximum eigenmode beamforming and SVD based spatial multiplexing schemes with different number of antenna configurations are compared. The detailed simulation of combined spatial multiplexing and space time coding is provided in both open loop and closed loop schemes.