Frequency domain channel estimation for OFDM based on Slepian basis expansion

In this paper we propose a low complexity frequency domain channel estimator for pilot-symbol-assisted (PSA) orthogonal frequency division multiplexing (OFDM) systems in a low mobility environment. We consider a situation where the receiver needs to estimate multipath channel with low complexity when only limited channel information is available. The proposed scheme relies on a recently proposed model, the Slepian basis expansion model, where Slepian sequences are used to exploit channel correlation in time. However, in slow fading channels, the length of the required Slepian sequence is very long and thus decoding complexity increases. To achieve accurate channel estimation with low complexity, we propose to utilize the Slepian sequences to exploit the frequency correlation of the channel. Simulation results show that the proposed channel estimator outperforms the channel estimator based on the exponential basis expansion model where the channel is approximated as a linear combination of complex exponential functions.