Patent ID: 7853219
Filing Date: 2010-12-14
Classification: H04B

Abstract:
1. A Doppler frequency detector which detects a Doppler frequency of a received signal, comprising: a channel estimating unit which calculates a channel estimate based on a pilot signal in the received signal; a channel phase variation amount calculating unit which calculates a channel phase variation amount based on said channel estimate and a calculation interval; a Doppler frequency estimating unit which estimates said Doppler frequency based on said channel phase variation amount and outputs a Doppler frequency estimate; and a calculation interval calculating unit which calculates said calculation interval based on said Doppler frequency estimate and supplies it to said channel phase variation amount calculating unit, wherein said calculation interval calculating unit updates said calculation interval to be smaller than a current value when said Doppler frequency estimate is larger than a first threshold value (TH1), and updates said calculation interval to be larger than said current value when said Doppler frequency estimate is smaller than a second threshold value (TH2; TH2≦TH1).