Adaptive Truncation of Channel Impulse Response and its Performance Evaluation

It is known that the performance of the fast Fourier transform (FFT) -based channel estimation approach is heavily affected by the length of the truncated channel impulse response. Unfortunately, a good algorithm to do so usually involves high computational complexity, and not suitable for fast-varying channels. To address this issue, we propose to use the metric available in the forward error correction block (e.g., conventional decoder) to adaptively adjust the window size for every OFDM symbol to deal with fast varying channels. We implement our algorithm to decode simulated and on-air DVB-T signals. Experimental results show that the proposed algorithm has comparable performance as the optimal-search approach in terms of error packets for on-air channels.