Cellular Cyclic Delay Diversity for Next Generation Mobile Systems

In this paper, we address a new method called cellular cyclic delay diversity (C-CDD) to a cellular mobile radio communications system. A promising candidate for a next generation mobile downlink is multi-carrier code division multiple access (MC-CDMA). The C-CDD technique is exemplarily applied to MC-CDMA. The cyclic delay diversity technique increases the diversity in a system by cyclically shifted replicas of the transmitted signal over several transmit antennas. For improving the performance at the cell border in a cellular system, we introduce the cyclic delay diversity principle by sending replicas of the desired signal including a cyclic shift from adjacent base stations. The resulting C-CDD scheme is standard conformable. Therefore, no additional change in the mobile terminal is needed to exploit the C-CDD. The influence of the cyclic delay to a cellular MC-CDMA system is investigated. Furthermore, simulation results show the significant improvement of the performance at the cell border by using C-CDD in an MC-CDMA cellular system for different transmission scenarios.