Efficient supporting methods for adaptive pilot-aided channel estimation in OFDM systems

Approaches for adaptive pilot-aided channel estimation in frequency domain are well established for orthogonal frequency-division multiplexing (OFDM) systems. To further enhance the performance of both the adaptive channel estimation and the entire receiver, three efficient supporting methods are discussed in this paper. First, the well-known concept of non-rectangular windowing is recalled due to its fundamental importance and benefits over the conventional rectangular windowing. Secondly, an approach is proposed to reduce the suboptimality of channel estimation algorithms applying real-valued filtering, which can even lead to convergence speed gains compared to complex valued filtering in scenarios where real-valued filters are theoretically suboptimum. Third, a novel scheme treating continuous as scattered pilots (CASP) is introduced to solve the reference data problem of adaptive channel estimation algorithms. Simulation results for a scenario according to the hybrid satellite/terrestrial broadcasting system DVB-SH, show that these methods combine a low complexity with a noticeably increased receiver robustness.