Performance aspects of transmit antenna diversity (TxAD) techniques for UTRA-TDD

The application of transmit antenna diversity (TxAD) to the TDD mode of UMTS is considered. After comparing TxAD with coherent receiver antenna diversity (CRAD) which is used in the uplink of all major digital mobile radio systems, the advantages and drawbacks of TxAD are discussed. Furthermore, simulation results for non-adaptive TxAD techniques are presented. The SNR (signal to noise ratio) gain achievable by the application of TxAD ranges from 0.5 dB to 2.7 dB, depending on the propagation environment as well as the TxAD technique applied.