Low Complexity Wiener Filter Based Channel Estimation in Pilot Aided OFDM Systems

A reduced complexity, Wiener filter based, channel estimation algorithm for OFDM systems is presented. The algorithm applies to pilot-aided OFDM systems and suites frequency-domain channel estimation-and-interpolation in the frequency direction as well as in the time direction. The algorithm leverages symmetry properties of the Wiener filter coefficients that are valid in common pilot allocation structures, like comb structure, and leads to 50% complexity reduction as compared to the direct implementation scheme of Wiener filter. In this paper, we derive the relationships between the pilot allocation and the symmetric characteristics of the Wiener filter coefficients, and show how this symmetry is leveraged toward significant reduction in the computational load of the channel estimation.