Guard-interval mode detection method for the Chinese DTTB System

Chinese digital television terrestrial broadcasting (DTTB) standard, digital terrestrial/television multimedia broadcasting (DTMB), recommends three padding modes of guard intervals (GI) with PN420/595/945 as training sequences for multi-carrier or single-carrier block transmission. At receiver side, mode detection should be done before subsequent synchronization and channel estimation. Simple and automatic mode detection is fairly important for multi-mode systems. In this paper, a novel multi-mode correlator is proposed to locate and distinguish the PN sequences padded in the GI with computational complexity comparable to that of the single-mode correlator. As a result, automatic GI mode detection can be done based on multi-mode correlation results. Simulation results show that the proposed scheme performs well under AWGN and multi-path channels and can be applied to the DTMB receiver-chip design directly.