Investigation on Transmit Diversity for Synchronization Channel in OFDM Based Evolved UTRA Downlink

Tins paper presents the most appropriate transmit diversity scheme for the synchronization channel (SCH) employing the latest radio interface for the SCH structure and sequences based on system-level simulations in the evolved UTRA downlink. The transmit diversity candidates assumed in the paper are preceding vector switching (PVS), time switched transmit diversity (TSTD), cyclic delay diversity (CDD), and frequency switched transmit diversity (FSTD) based on the features of the SCH. Simulation results show that transmit diversity is effective in increasing detection probabilities of SCH timing detection in the first step and the cell ID group-specific SCH sequence in the second step of the cell search process. Moreover, we clarify that PVS is the best transmit diversity scheme for the SCH based on the reduction in the cell search time. We show that PVS achieves fast cell search in less than approximately 20 msec at the location probability of 90% regardless of the inter-site distance up to 10 km.