Performance analysis of CDMA transmit diversity methods

The link performance of transmit diversity (TD) schemes for third generation CDMA systems is analyzed. Orthogonal transmit diversity (OTD) and space-time transmit diversity (STTD) are compared. It is shown that the link performances of OTD and STTD are nearly the same. However, STTD requires additional receiver processing, and STTD is not directly extendable to more than 2 antennas, because rate one space-time block codes do not exist for greater than 2 antennas. Also, an interleaving approach is shown that works for various TD schemes as well as non-TD.