APPARATUS AND METHOD FOR FREQUENCY OFFSET ASSUMPTION IN OFDM SYSTEM

摘要

An apparatus and a method for estimating a frequency offset in an OFDM(Orthogonal Frequency Division Multiplexing) system are provided to maintain a stable synchronous performance by not reflecting an offset value lower than a threshold value to frequency compensation. An apparatus for estimating a frequency offset in an OFDM system includes a multiplying unit(101), a summing unit(102), an angle detecting unit(103), a weak electric field judging unit(104), and a frequency determining unit(105). The multiplying unit(101) multiplies an input signal by a complex conjugate of a signal obtained by delaying the input signal. The summing unit(102) accumulates output values of the multiplying unit(101) during a protection period to obtain a correlation value. The angle detecting unit(103) detects an angle of the correlation value from the summing unit(102). The weak electric field judging unit(104) compares an output of the summing unit(102) with a predetermined threshold value and judges a weak electric field. The frequency determining unit(105) applies a frequency offset value to frequency compensation according to a judgement result of the weak electric field judging unit(104).