| Today's wireless communication systems require more efficiency in terms of data rate. One of the ways to improve channel capacity of such systems is to utilize diversity. Space-time block codes provide transmit diversity gain without any significant increase in complexity of systems. However in some cases, the gain by utilizing diversity decreases due to some factors. In this work we studied two of these factors and their effects to several space-time block coded systems. The first factor is the spatial correlation among channels and the second factor is channel estimation errors. Both of these factors are experienced in real life situations. The systems under consideration are 2, 3 and 4 antenna orthogonal and quasi-orthogonal space-time block coded systems. We have also compared the results with the maximum ratio combining schemes with 2 and 4 receiver antennas. |
