Self-adapting cyclic delay diversity system

Cyclic Delay Diversity (CDD) is a simple and efficient space-time diversity technique. It can be used in OFDM and DFT-Spread-OFDM. The traditional CDD has low complexity and system overhead, however, also has some limitations on performance and is sensitive to propagation environment. In this paper, two improved CDD scheme including open-loop and close-loop strategies for uplink and downlink of EUTRA LTE are introduced. Compared with the conventional method, the new schemes can obtain higher performance and less sensitivity to environment.