Abstract: The method contains the following steps. First, in a MCM system with N sub-carriers, the baseband signal blocks Xj, j=1, 2, . . . ,B are supplemented with zeros and processed with LN-point IFFT, respectively, to obtain L-time oversampled time-domain signal blocks xj, j=1,2, . . . ,B. Then, xj undergoes Q Time Domain Circular Shifts or Frequency Domain Circular Shifts to obtain Q signal blocks {tilde over (x)}j(ij), ij=1, ?, Q. Subsequently, a B×B unitary transform is performed against ( x1, {tilde over (x)}2(i2), . . . , {tilde over (x)}B(iB)). After the unitary transform, for each (i2, . . . , iB) a combination having B time-domain signal blocks is obtained as follows: ({tilde over (y)}1(i2, . . . , iB), {tilde over (y)}2(i2, . . . , iB), . . . , {tilde over (y)}B(i2, . . . ,iB))=( x1, {tilde over (x)}2(i2), . . . , {tilde over (x)}B(iB)) cU where U is the B×B unitary matrix, and c is an arbitrary constant (c?0).

Abstract: A circuit and method for timing recovery. The circuit for timing recovery comprises an converter, a timing recovery controller, and a initial phase generator. The converter converts an input signal to sample data with a sampling signal. The timing recovery controller is coupled to the converter, and determines the sampling signal. And the initial phase generator is coupled to the AD converter, detects a change with the sample data only, produces an initial phase based on the change, and controls the sampling signal.

Abstract: The method contains the following steps. First, in a MCM system with N sub-carriers, the baseband signal blocks Xj, j=1, 2, . . . ,B are supplemented with zeros and processed with LN-point IFFT, respectively, to obtain L-time oversampled time-domain signal blocks xj, j=1,2, . . . ,B. Then, xj undergoes Q Time Domain Circular Shifts or Frequency Domain Circular Shifts to obtain Q signal blocks {tilde over (x)}j(ij), ij=1,?,Q. Subsequently, a B×B unitary transform is performed against ( x1,{tilde over (x)}2(i2), . . . ,{tilde over (x)}B(iB)). After the unitary transform, for each (i2, . . . ,iB) a combination having B time-domain signal blocks is obtained as follows: ({tilde over (y)}1(i2, . . . ,iB),{tilde over (y)}2(i2, . . . ,iB), . . . ,{tilde over (y)}B(i2, . . . ,iB)=( x1,{tilde over (x)}2(i2), . . . ,{tilde over (x)}B(iB)) cU where U is the B×B unitary matrix, and c is an arbitrary constant (c?0).

Abstract: A circuit for improving accuracy of channel impulse response estimation and compensating for remnant frequency offset in a receiver of an orthogonal frequency division multiplexing (OFDM) system is provided. The circuit comprises an equalizer, for compensating a first signal for channel distortion with the channel impulse response estimate to generate a second signal. The circuit also comprises a remnant frequency compensation module, coupled to the equalizer, for rotating a phase of the second signal with a phase angle of an phase offset coefficient calculated according to a plurality of pilot signals of the second signal to generate a third signal. The circuit further comprises a error estimation module, coupled to the remnant frequency compensation module, for generating an error estimate according to the third signal and its hard decision estimate, and the error estimate is further fed back to the equalizer to refine the channel impulse response estimate.

Abstract: A method for network diagnosis between a source end and a destination end coupled by a transmission line is provided. The method includes the following steps. First, a first test signal is transmitted from the transmitter to the receiver when the hybrid is set to a first mode. Next, a plurality of first coefficients are extracted from the first test signal received by the canceller during a first period, wherein each one of the first coefficients has an index corresponding to a received order. And then, the hybrid is switched to a second mode to generate a second test signal by sending an original signal to the receiver and the destination. Sequentially, a plurality of second coefficients are extracted from the second test signal received by the canceller during a second period, wherein each one of the second coefficients has an index corresponding to a received order. Therefore, a first index is determined when an absolute value of one of the first coefficients substantially exceeds a first threshold value.

Abstract: A method for updating coefficients in a decision feedback equalizer (DFE). The DFE comprises an ISI canceler for canceling inter-symbol interference (ISI) from a plurality of first signals received from a channel. A first symbol comprising a set of the first signals is decoded to generate a decoded symbol. Then, a vector of error values computed as the difference between the decoded symbol, and the first symbol is obtained. According to the decoded symbol and the vector of the error values, a temp matrix is generated. Next, the values of the elements in every diagonal line of the temp matrix are averaged. Finally, the coefficients are updated by the Toeplitz Matrix.

Abstract: A circuit and method for timing recovery. The circuit for timing recovery comprises an converter, a timing recovery controller, and a initial phase generator. The converter converts an input signal to sample data with a sampling signal. The timing recovery controller is coupled to the converter, and determines the sampling signal. And the initial phase generator is coupled to the AD converter, detects a change with the sample data only, produces an initial phase based on the change, and controls the sampling signal.

Abstract: A circuit for improving accuracy of channel impulse response estimation and compensating for remnant frequency offset in a receiver of an orthogonal frequency division multiplexing (OFDM) system is provided. The circuit comprises an equalizer, for compensating a first signal for channel distortion with the channel impulse response estimate to generate a second signal. The circuit also comprises a remnant frequency compensation module, coupled to the equalizer, for rotating a phase of the second signal with a phase angle of an phase offset coefficient calculated according to a plurality of pilot signals of the second signal to generate a third signal. The circuit further comprises a error estimation module, coupled to the remnant frequency compensation module, for generating an error estimate according to the third signal and its hard decision estimate, and the error estimate is further fed back to the equalizer to refine the channel impulse response estimate.

Abstract: A method for updating coefficients in a decision feedback equalizer (DFE). The DFE comprises an ISI canceller for canceling ISI from a plurality of first signals received from a channel. A first symbol comprising a set of the first signals is decoded to generate a decoded symbol. Then, a vector of error values computed as the difference between the decoded symbol, and the first symbol is obtained. According to the decoded symbol and the vector of the error values, a temp matrix is generated. Next, the values of the elements in every diagonal line of the temp matrix are averaged. Finally, the coefficients are updated by the Toeplitz Matrix.