Optimum channel estimation pilot design for CDD-OFDM with application to DVB

Cyclic delay diversity (CDD) is a low-complexity standard-conformable transmit diversity technique for coded orthogonal frequency division multiplexing (OFDM) systems. However, it makes channel estimation more challenging due to the increased frequency-selectivity of the channel. In this paper, we propose a novel pilot-aided channel estimation scheme for CDD-OFDM. By alternating and optimizing the cyclic delay parameter for adjacent OFDM symbols, we design a simple yet efficient channel estimation scheme for frequency-selective channels and evaluate its effectiveness for a DVB-T system.