Patent ID: 8416676

Claim:
A method for estimating and compensating sampling clock offset (SCO) for a multi-band orthogonal frequency division multiplexing (OFDM)-based ultra-wideband (UWB) system on a plurality of transmitted OFDM symbols; the transmitted OFDM symbols being divided into groups, indexed with m; each group having K OFDM symbols, indexed with i, i=0, 1, . . . , K−1; each OFDM symbol having R pilot subcarriers, ascendingly indexed with {p(0), p(1), . . . , p(R−1)}; a method for obtaining an accumulated normalized SCO (ANSCO) estimation, {circumflex over (η)} m+1 (i) , on the ith OFDM symbol in the (m+1)th group, using an ANSCO estimation {circumflex over (η)} m (i) , on the ith OFDM symbol in the mth group, comprising: grouping R pilot subcarriers into Q pilot pairs; each pilot pair, {p(l 1 ), p(l 2 )}, having a separation factor, β(l 1 ,l 2 ); obtaining a channel frequency response (CFR) estimation, h r , on an rth sub-band; obtaining a pilot-subcarrier related input of an N-point inverse discrete Fourier transform (IDFT) processor and a pilot-subcarrier related output of an N-point discrete Fourier transform (DFT) processor; obtaining a residual SCO estimation related value, b m (i) (l 1 ,l 2 ), by using a pilot-pair related input of the IDFT processor, a pilot-pair related output of the DFT processor and a pilot-pair related CFR estimation, where the pilot-pair indicates one pilot pair {p(l 1 ), p(l 2 )} in the R pilot subcarriers of the ith OFDM symbol in the mth group; summing up Q residual SCO estimation related values, respectively obtained from the Q pilot pairs of the ith OFDM symbol in the mth group to yield a symbol-level residual SCO estimation related value, γ m (i) ; obtaining a combined residual SCO estimation, Δ{circumflex over (η)} m , by using K symbol-level residual SCO estimation related values, γ m (0) , γ m (1) , . . . , γ m (K−1) , respectively obtained from the K OFDM symbols in the mth group; obtaining the ANSCO estimation, {circumflex over (η)} m+1 (i) , based on the combined residual SCO estimation, Δ{circumflex over (η)} m and the ANSCO estimation {circumflex over (η)} m (i) , on the ith OFDM symbol in the mth group, dividing the ANSCO estimation into integer and fractional portions; shifting sample timing at an interval of a sampling period in the time-domain by an amount of the modulus of the integer portion of the ANSCO estimation; and correcting a phase shift in the frequency-domain with a rotating factor corresponding to the fractional portion of the ANSCO estimation.