Improved CIR-Based Receiver Design for DVB-T2 System in Large Delay Spread Channels: Synchronization and Equalization

This paper proposes to implement an improved orthogonal frequency division multiplexing (OFDM) receiver by utilizing a channel impulse response (CIR)-based synchronization and sparse equalization for DVB-T2 system operating in both the single-input single-output (SISO) and multi-input single-output (MISO) transmission modes. First, the proposed OFDM receiver performs a pilot-aided CIR estimation after a coarse symbol timing recovery (STR). Then, the proposed CIR-based fine STR compensates for a false symbol timing offset (STO). In particular, the fine STR resolves an ambiguity effect of CIR, which is the main problem caused by a false coarse STO in exploiting the CIR. Upon the completion of the fine synchronization, the proposed CIR-based sparse equalization is performed in order to minimize the noise and interference effects by shifting or selecting a basic frequency interpolation (FI) filter according to an echo delay (phase) or maximum delay spread, respectively. Performance evaluations are accomplished in large delay spread channels in which the maximum delay spread is less or longer than a guard interval (GI). It is shown that the proposed receiver is not only capable of estimating the fine STO but also minimizing effectively the noise effects. In particular, the performance gain in a single pre-echo channel being longer than GI is remarkable as compared with a conventional receiver.