On the Pilot-Symbol Aided Channel Estimation Analysis of Cyclic Delay Diversity for OFDM Systems

Cyclic delay diversity (CDD) is a suggested spatial diversity transmission scheme applied in OFDM system to mitigate intersymbol interference while optimizing channel bandwidth. The increased diversity in the frequency domain caused by the cyclic delays renders channel estimation difficult. In this paper we investigate the effect of pilot-symbol aided channel estimation of CDD-OFDM systems, considering two approaches: first the zero pilot pattern which uses all available pilot simultaneously; second the non-zero pattern where pilots are allocated for each transmit antenna exclusively. The wiener filter is derived for the two approaches. Performance is presented in terms of the bit error rate (BER) and mean square estimation (MSE) obtained from computer simulation.