  The power spectrum, as a statistic in Fourier space, is commonly numerically
calculated using the fast Fourier transform method to efficiently reduce the
computational costs. To alleviate the systematic bias known as aliasing due to
the insufficient sampling, the interlacing technique was proposed. We derive
the analytical form of the shot noise under the interlacing technique, which
enables the exact separation of the Poisson shot noise from the signal in this
case. Thanks to the accurate shot noise subtraction, we demonstrate an
enhancement in the accuracy of power spectrum estimation, and compare with the
other widely used estimators in community. The good performance of our
estimation allows an abatement in the computational cost by using low
resolution and low order mass assignment scheme in the analysis for huge
surveys and mocks.
