Patent ID: 7564909
Filing Date: 2009-07-21
Classification: H04L

Abstract:
1. A base station apparatus in a broadband mobile communication system, comprising: a ranging subchannel extractor for extracting subcarrier values with a ranging signal from a fast Fourier transform (FFT) signal; a plurality of multipliers for code-demodulating the subcarrier values by multiplying the subcarrier values by a plurality of ranging codes; a plurality of correlators, each for calculating a plurality of differential correlations in a code-demodulated signal received from a corresponding multiplier; a plurality of inverse fast Fourier transform (IFFT) processors, each for IFFT-processing differential correlations received from a corresponding correlator by mapping the differential correlations to predetermined subcarriers; and a plurality of maximum value detectors, each for detecting a maximum value in an IFFT signal received from a corresponding IFFT processor and calculating a timing offset using an IFFT output index having the maximum value; wherein each of the correlators calculate 2×k and wherein k is an input index of a J-point IFFT processor, L+1 is a number of subbands, N+1 is a number of subcarriers per subband, Y 1,n is a received signal response of an n th subcarrier in an 1 th subband, C 1,n is a ranging code bit allocated to the n th subcarrier in the 1 th subband, and k max =N.