A Channel Estimation Technique for Hierarchical DVB-T System to Extract High-Priority Stream

In this paper a low-cost channel estimation technique for DVB-T systems with hierarchical modulation to extract only high-priority (HP) stream, is proposed. The proposed approach is based on the estimation and correction of the phase component of channel frequency response. In this way, this phase is considered while the magnitude is neglected. As will be shown, ignoring low- priority (LP) stream, we can perform demapping of HP stream, just by compensation of the phase of demodulated complex symbols. Compared with conventional channel estimation techniques, the major advantage of this technique is its simplicity and low computational complexity, but at the cost of losing LP stream. In fact, the aim is decoding and demodulation of just HP stream when hierarchical scheme is employed in the DVB-T transmitter. Simulation is performed to evaluate BER of HP stream versus channel SNR to validate the estimation method.