Via Technologies, Inc.

Kai-Pon Kao

Tien-Hui Chen

ChinGwo Ma

Jeff Lin

Chingwo Ma

Chih-Chia Wang

A method for frequency offset estimation in frequency domain is provided. The method comprises the following steps. First, a phase angle of a signal field of the input signal after processed by Fast Fourier Transformation (FFT) and channel equalization is calculated. A frequency offset error originated from at least one frequency offset estimation process in time domain is then estimated according to the phase angle.

Method and circuit for frequency offset estimation in frequency domain in the orthogonal frequency division multiplexing baseband receiver for IEEE 802.11a/g wireless LAN standard

A method for fine timing synchronization is provided. The method comprises: detecting an end point of the short preamble; delivering the samples after the end point to a matched filter to generate a plurality of correlation peaks; searching the correlation peaks generated from the samples of the first LTS for a first maximal peak point which is the correlation peak with a first maximal intensity, and obtaining the first time index of the first maximal peak point; searching the correlation peaks generated from the samples of the first LTS for a pre-peak point which is the correlation peak forming a peak intensity appearing before and nearest to the first maximal peak point, and obtaining the second time index of the pre-peak point; estimating a third time index of the start point of the second LTS according to the first and second time indexes.

Method and circuit for fine timing synchronization in the orthogonal frequency division multiplexing baseband receiver for IEEE 802.11a/g wireless LAN standard

Method and circuit for frequency offset estimation in frequency domain in the orthogonal frequency division multiplexing baseband receiver for IEEE 802.11A/G wireless LAN standard

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.

Circuit for improving channel impulse response estimation and compensating for remnant frequency offset in the orthogonal frequency division multiplexing (OFDM) baseband receiver for IEEE 802.11a/g wireless LAN standard

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.

Method for updating coefficients in decision feedback equalizer

An Automatic Gain Control (AGC) method and system thereof. The power of a detected signal is first checked to ensure that it is large enough for AGC process. A power average of the detected signal is computed and compared to a first threshold in order to determine whether to proceed with a coarse tune procedure or enter a fine tune procedure. Both Low Noise Amplifier (LNA) gain and Variable Gain Amplifier (VGA) gain are tuned during coarse tune, whereas only the VGA gain is tuned during fine tune. The LNA and VGA gains are tuned to predetermined values during coarse tune, and the VGA gain is adjusted according to a difference between a computed average of power and a second threshold.

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Hsinchu, Taiwan

Kai-Pon Kao