Patent ID: 8179953

Claim:
A mobile station apparatus, comprising: a first estimation unit configured to estimate a delay spread of a transmission channel and a Doppler frequency based on a downlink signal including pilots received from a base station apparatus; a determination unit configured to select, based on the delay spread and the Doppler frequency, an interpolation method to be applied to the pilots from a first interpolation method and a second interpolation method, the first interpolation method performing time-direction interpolation and then performing frequency-direction interpolation using a result of the time-direction interpolation, the second interpolation method performing frequency-direction interpolation and then performing time-direction interpolation using a result of the frequency-direction interpolation of the second interpolation method; and a second estimation unit configured to perform interpolation using the selected interpolation method to estimate the transmission channel, wherein the determination unit obtains a first frequency-direction resource element spacing, with which transmission channel characteristics in a frequency direction are obtained if one of the first and the second interpolation methods is applied, and a first time-direction resource element spacing, with which transmission channel characteristics in a time direction are obtained if the one of the first and the second interpolation methods is applied, and determines the one of the first and the second interpolation methods as the interpolation method to be applied if the first frequency-direction resource element spacing and the first time-direction resource element spacing satisfy a condition that allows the interpolation to be performed.