A novel transmission scheme employing virtual subcarrier in TDS-OFDM system

The Chinese digital terrestrial/television multimedia broadcasting (DTMB) standard adopts time-domain synchronous orthogonal frequency division multiplexing (TDS-OFDM) as the modulation technology. TDS-OFDM system uses time domain PN sequences as frame header and thus has to employ square root raised cosine (SRRC) filters to perform spectrum shaping. In order to ensure synchronization performance, the system needs oversampling and symbol timing recovery (STR), which is sensitive to sampling position offset and increases the implementation complexity. In this paper, a novel transmission scheme utilizing virtual subcarrier is proposed to mitigate this problem. The proposed system does not require oversampling and SRRC filters. Compared with the conventional TDS-OFDM system, simulation results prove that the proposed scheme has better performance in presence of sampling position offset in various multipath channels.