Patent ID: 7916660

Claim:
A noise power estimation apparatus comprising: a sampling processor for sampling a pilot signal on a complex plane at a constant sampling interval in a frequency domain to output a plurality of received pilot signals r m , where m indicates an integer; a pilot signal estimation section for estimating, according to the plurality of received pilot signals r m obtained by sampling in the frequency domain by the sampling processor, a received pilot signal r 0 having any frequency by using a plurality of pilot signals r m (m≠0) having other frequencies by a sampling theorem, which is used to reproduce frequency components included in a continuous signal as sampling data, to obtain an estimated received pilot signal r 0 ′; and a noise power calculator for applying statistical averaging to the difference between the received pilot signal r 0 having the any frequency, output from the sampling processor, and the estimated received pilot signal r 0 ′, estimated by the pilot signal estimation section; wherein the noise power calculator, according to the following expression, | r 0 −r 0 ′| 2 = |n 0 −n 0 ′| 2 = |n 0 | 2 + |n 0 ′| 2 =2σ 2 < >: an expected value n 0 : noise component of received pilot signal n 0 ′: noise component of estimated pilot signal, calculates the difference between the actually received pilot signal r 0 having the any frequency and the estimated received pilot signal r 0 ′ estimated by the pilot signal estimation section, and applies statistical averaging to the difference within a given period of time determined in advance to obtain variance σ 2 as the noise power.