Patent ID: 9319840
Filing Date: 2016-04-19
CPC Classification: G01S,H04W

Claim Text:
1. A method for estimating a distance of a mobile terminal comprising a radio receiver, from at least one base station comprising a radio transmitter, comprising the steps of: receiving, at said radio receiver, radio signals irradiated by said radio transmitter, said radio signals corresponding to an OFDM signal comprising a plurality of subcarriers from which a plurality of corresponding tones is extractable; extracting from said subcarriers of said OFDM signal at least three tones, each having a different frequency; measuring a first phase difference between a first two tones of said at least three tones, whose frequencies have a first spacing, and measuring a second phase difference between a second two tones of said at least three tones, whose frequencies have a second spacing, wherein one of said first spacing or second spacing is greater than the other; estimating said distance on a basis of said first phase difference and said second phase difference; and correcting the estimated distance based on characteristics of a transfer function of a radio channel that includes the OFDM signal, the transfer function being related to a periodicity interval of a distortion present in a frequency spectrum of the radio channel, said distortion characterizing the signal path which separates said base station from said radio receiver.