Noise power estimation apparatus and method
AssigneeHitachi, Ltd.
InventorsYasutaka MORINAGA, Mikio Kuwahara
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Abstract
A pilot signal is estimated by using the sampling theorem to estimate noise power in a stable manner without depending on the signal to noise ratio. A pilot signal estimation section obtains an estimated pilot signal by using the sampling theorem according to a plurality of received pilot signals sampled in the frequency domain by a sampling processor. A noise power estimation section estimates noise power by applying statistical averaging to the difference between the received pilot signal received from the sampling processor and the estimated pilot signal received from the pilot signal estimation section.
Claims10
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 rm, where m indicates an integer;
- a pilot signal estimation section for estimating, according to the plurality of received pilot signals rm obtained by sampling in the frequency domain by the sampling processor, a received pilot signal r0 having any frequency by using a plurality of pilot signals rm (m≠0) having other frequencies by the sampling theorem, which is used to reproduce frequency components included in a continuous signal as sampling data, to obtain an estimated received pilot signal r0′;
- and
- a noise power calculator for applying statistical averaging to the difference between the received pilot signal r0 having the any frequency, output from the sampling processor, and the estimated received pilot signal r0′, estimated by the pilot signal estimation section;
- wherein
- the noise power calculator, according to the following expression,
- |r0−r0′|2=|n0−n0′|2=|n0|2+|n0′|2=2σ2
- where < > indicates an expected value, calculates the difference between the actually received pilot signal r0 having the any frequency and the estimated received pilot signal r0′ estimated by the pilot signal estimation section, and applies statistically averaging to the difference within a given period of time determined in advance to obtain variance σ2 as the noise power.
A noise power estimation method comprising the steps of:
- 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 rm, where m indicates an integer;
- pilot-signal-estimating for estimating, according to the plurality of received pilot signals rm obtained by sampling in the frequency domain by the sampling step, a received pilot signal r0 having any frequency by using a plurality of pilot signals rm (m≠0) having other frequencies by the sampling theorem, which is used to reproduce frequency components included in a continuous signal as sampling data, to obtain an estimated received pilot signal r0′;
- and
- noise-power-calculating for applying statistical averaging to the difference between the received pilot signal r0 having the any frequency, output from the sampling step, and the estimated received pilot signal r0′, estimated by the pilot-signal-estimating step;
- wherein
- the noise-power-calculating step, according to the following expression,
- |r0−r0′|2=|n0−n0′|2=|n0|2+|n0′|2=2σ2
- where < > indicates an expected value, calculates the difference between the actually received pilot signal r0 having the any frequency and the estimated received pilot signal r0′ estimated by the pilot-signal-estimating step, and applies statistically averaging to the difference within a given period of time determined in advance to obtain variance σ2 as the noise power.
Dependencies are inferred from the claim text.