Abstract: An apparatus for sampling clock recovery (SCO) and methods for estimating and compensating SCO are provided. The apparatus comprises a symbol timing adjustment module for shifting forward or backward symbol timing of the transmitted OFDM symbols; a discrete Fourier transform (DFT) processor for performing DFT to an output from the symbol timing adjustment module; a channel estimator for undertaking a channel frequency response estimation based on a channel estimation sequence; a SCO phase rotator for receiving and performing phase shift on the transmitted OFDM symbols of a frame header and a frame payload; an SCO estimation stage for undertaking an SCO estimation based on a pilot-subcarrier-related output of the SCO phase rotator and the CFR estimation; and an SCO compensation distributor for dividing the SCO estimation into integer and fractional portions and then distributing them into the symbol timing adjustment module and the SCO phase rotator, respectively.

Abstract: A multi-stage CFR estimation method for multi-band OFDM-based UWB systems is provided. The method includes obtaining a CFR estimation ?r(1) by performing LS estimation using a channel estimation sequence from a received OFDM-UWB frame; obtaining a CFR estimation ?r(2) by applying a frequency-domain smoothing to the CFR estimation ?r(1) with a first smoothing factor; obtaining a frame header which contains OFDM symbols transmitted with frequency-domain spreading on each OFDM symbol, and detecting signal signs based on a combination of two spread signals of the same OFDM symbol in the frame header with a decision directed mode and the CFR estimation ?r(2) assisted; obtaining a CFR estimation ?r(3) by using the signs and a finite-alphabet feature of the detected transmitted signals; obtaining a CFR estimation ?r(4) by applying a frequency-domain smoothing to the CFR estimation ?r(3) with a second smoothing factor; and obtaining a CFR estimation ?r by averaging the CFR estimations ?r(2) and ?r(4).

Abstract: Method and apparatus for receiving coded signals with the aid of CSI are provided. The method comprises: performing channel estimation to obtain a CFR estimation vector; computing a squared magnitude of the CFR estimation vector, and obtaining a normalization factor ? by averaging the squared magnitudes of CFR estimations on all N subcarriers; finding a norm-shift operand m satisfying the condition that ?0=2m is a power of 2 number closest to the normalization factor ?; performing a CSI-aided one-tap channel equalization on an output signal vector from a DFT processor by using the norm-shift operand m; performing constellation demapping; and performing channel decoding. The method further comprises obtaining a weighting factor vector by right shifting m bits of the squared magnitude of the CFR estimation vector so that the constellation demapping can use the weighted decision boundary values in case that its input signal is sensitive to both amplitude and phase.

Abstract: An apparatus for sampling clock recovery (SCO) and methods for estimating and compensating SCO are provided. The apparatus comprises a symbol timing adjustment module for shifting forward or backward symbol timing of the transmitted OFDM symbols; a discrete Fourier transform (DFT) processor for performing DFT to an output from the symbol timing adjustment module; a channel estimator for undertaking a channel frequency response estimation based on a channel estimation sequence; a SCO phase rotator for receiving and performing phase shift on the transmitted OFDM symbols of a frame header and a frame payload; an SCO estimation stage for undertaking an SCO estimation based on a pilot-subcarrier-related output of the SCO phase rotator and the CFR estimation; and an SCO compensation distributor for dividing the SCO estimation into integer and fractional portions and then distributing them into the symbol timing adjustment module and the SCO phase rotator, respectively.

Abstract: An apparatus for sampling clock recovery (SCO) and methods for estimating and compensating SCO are provided. The apparatus comprises a symbol timing adjustment module for shifting forward or backward symbol timing of the transmitted OFDM symbols; a discrete Fourier transform (DFT) processor for performing DFT to an output from the symbol timing adjustment module; a channel estimator for undertaking a channel frequency response estimation based on a channel estimation sequence; a SCO phase rotator for receiving and performing phase shift on the transmitted OFDM symbols of a frame header and a frame payload; an SCO estimation stage for undertaking an SCO estimation based on a pilot-subcarrier-related output of the SCO phase rotator and the CFR estimation; and an SCO compensation distributor for dividing the SCO estimation into integer and fractional portions and then distributing them into the symbol timing adjustment module and the SCO phase rotator, respectively.

Abstract: An apparatus for sampling clock recovery (SCO) and methods for estimating and compensating SCO are provided. The apparatus comprises a symbol timing adjustment module for shifting forward or backward symbol timing of the transmitted OFDM symbols; a discrete Fourier transform (DFT) processor for performing DFT to an output from the symbol timing adjustment module; a channel estimator for undertaking a channel frequency response estimation based on a channel estimation sequence; a SCO phase rotator for receiving and performing phase shift on the transmitted OFDM symbols of a frame header and a frame payload; an SCO estimation stage for undertaking an SCO estimation based on a pilot-subcarrier-related output of the SCO phase rotator and the CFR estimation; and an SCO compensation distributor for dividing the SCO estimation into integer and fractional portions and then distributing them into the symbol timing adjustment module and the SCO phase rotator, respectively.

Abstract: A multi-stage CFR estimation method for multi-band OFDM-based UWB systems is provided. The method comprises obtaining a CFR estimation ?r(1) by performing LS estimation using a channel estimation sequence from a received OFDM UWB frame; obtaining a CFR estimation ?r(2) by applying a frequency-domain smoothing to the CFR estimation ?r(1) with a first smoothing factor; obtaining a frame header which contains OFDM symbols transmitted with frequency-domain spreading on each OFDM symbol, and detecting signal signs based on a combination of two spread signals of the same OFDM symbol in the frame header with a decision directed mode and the CFR estimation ?r(2) assisted; obtaining a CFR estimation ?r(3) by using the signs and a finite-alphabet feature of the detected transmitted signals; obtaining a CFR estimation ?r(4) by applying a frequency-domain smoothing to the CFR estimation ?r(3) with a second smoothing factor; and obtaining a CFR estimation ?r by averaging the CFR estimations ?r(2) and ?r(4).

Abstract: Method and apparatus for receiving coded signals with the aid of CSI are provided. The method comprises: performing channel estimation to obtain a CFR estimation vector; computing a squared magnitude of the CFR estimation vector, and obtaining a normalization factor ? by averaging the squared magnitudes of CFR estimations on all N subcarriers; finding a norm-shift operand m satisfying the condition that ?0=2m is a power of 2 number closest to the normalization factor ?; performing a CSI-aided one-tap channel equalization on an output signal vector from a DFT processor by using the norm-shift operand m; performing constellation demapping; and performing channel decoding. The method further comprises obtaining a weighting factor vector by right shifting m bits of the squared magnitude of the CFR estimation vector so that the constellation demapping can use the weighted decision boundary values in case that its input signal is sensitive to both amplitude and phase.