Silicon Integrated Systems Corporation

Ralink Technology Corporation

Mediatek Corporation

Ching-Kae Tzou

Min-Chieh Chen

Hsien-Chun Huang

Shuenn-Ren Liu

Shih-Chung Yin

Shang-Ho Tsai

Dong-Ming Chuang

Yuan-Hwa Li

Wei-Gian Chen

Yung Ching Lin

Song-Nien Tang

Shu-Fa Yang

Yang-Chung Tseng

The present invention discloses a transmission power control method for a communication system comprising a transmitter and a plurality of receivers. The transmitter is coupled to the plurality of receivers via a plurality of corresponding outgoing links. The transmission power control method comprising steps of each of the plurality of receivers performing channel estimation for each of the plurality of corresponding outgoing links, and replying a first suggested transmission power back-off level to the transmitter; and the transmitter determining a new transmission power back-off level after collecting a plurality of first suggested transmission power back-off levels from the plurality of receivers.

Transmission power control method

A method of noise mitigation in a multi-carrier communication system includes receiving a signal from a decision device, determining whether synchronization symbol update is enabled, updating at least one of frequency-domain equalizer (FEQ) coefficients or digital echo canceller (DEC) coefficients in synchronization symbol periods if the synchronization symbol update is enabled, determining whether data symbol update is performed if the synchronization symbol update is not enabled, determining whether a flag associated with the signal is set if the data symbol update is not performed, and updating at least one of FEQ or DEC coefficients associated with the signal in synchronization symbol periods if the flag is set.

Method for impulse noise mitigation

The present invention discloses a scattering-parameter estimation method for a transceiver of a half-duplex multicarrier communication system. The scattering-parameter estimation method includes steps of converting a first frequency-domain transmit signal to generate at least one symbol period of the first time-domain transmit signal; transmitting the first time-domain signal in a first specific time period; receiving and storing at least one symbol period of the first echoed signal of the first time-domain transmit signal in the first specific time period; converting at least one symbol period of the first echoed signal into a first frequency-domain echoed signal after a first transmission period; and estimating the S11 parameters corresponding to carriers respectively according to the first transmit signal and the first echoed signal.

Scattering-parameter estimation method and transceiver using the same

A collision detection method for a multiple access communication system is disclosed. By using the error term of a time-domain equalized signal as a detection source, an operation on the error term can be performed to determine whether collision occurs. For example, the mean square error and/or maximum value of the real part and/or imaginary part of the error term can be calculated or selected to distinguish the collision and non-collision situations. A collision detection apparatus for a multiple access communication system is also disclosed. The collision detection apparatus utilizes an existent adaptive equalizer and signal processing device for obtaining received information data bits to obtain the error term. The error term is further processed by a mean-square-error or maximum-absolute-value operator to determine the collision status.

Collision detection method and apparatus for multiple access communication system

A differential phase discriminator includes a phase compensation circuit to compensate for timing drift and error for recovering timing information in a digital phase lock loop. The differential phase discriminator uses a differential phase detector to compute the phase difference of two consecutive frequency domain signal samples. The phase compensation circuit determines a phase correction term by computing the difference between the absolute values of the real and imaginary parts of a frequency domain signal sample. A weighting factor is computed by adjusting the sum of the absolute values of the real and imaginary parts of the frequency domain signal sample with a ratio adjustment factor. A phase compensation value is then computed by multiplying the phase correction term by the weighting factor. The phase compensation value is added to the uncorrected output of the differential phase detector.

Phase discriminator with a phase compensation circuit

A method and an apparatus are provided in this invention to select an optimal swapping technique in discrete multi-tone system. The algorithm for performing gain-swapping is also proposed in the present invention. A swapping technique is selected from gain-swapping and a combination of bit-swapping and gain-swapping based on two index values such that the difference between the maximum mean square error (MSE) and the minimum mean square error (MSE) is minimized and the gain factor constraints are met. The first index value I is representative of range of improvement when adopting the gain-swapping as the swapping technique, and the second index value J is representative of range of improvement when adopting a combination of the gain-swapping and the bit-swapping as the swapping technique.

Method and apparatus for selecting an optimal swapping technique in discrete multi-tone system

Architecture of an efficient adaptive digital echo canceller includes a frequency domain update block, a far-end signal estimation block and a time domain echo cancellation block. The echo canceller has a training mode in which the frequency domain update block and far-end signal estimation block are first trained to estimate the echo channel and target channel. After the training mode, the time domain echo cancellation block uses the estimated echo channel to synthesize an echo replica and subtracted it from the received signal continuously before or in an operation mode. When a synchronization frame is received in the operation mode, the frequency domain update block and the far-end signal estimation block are used to retune both echo channel and target channel for improving system performance.

Efficient echo canceller for ADSL applications

An apparatus is adapted for interleaving an incoming stream of data blocks, each of which has a predetermined number (N) of block units indexed consecutively from 0 to (N&minus;1), The interleaving is accomplished at a predetermined interleaving depth (D). A first one of the block units has no delay associated therewith, and subsequent ones of the block units in a designated one of the data blocks have a delay equal to (D&minus;1) more than an immediately preceding one of the block units in the designated one of the data blocks. The apparatus includes a data buffer configured to have a number of lines equal to (N&minus;1), an output unit, and a control unit. Each of the lines has a size sufficient to accommodate a predetermined number of the block units. The output unit outputs one of the block units of the incoming stream directly when the delay associated therewith is equal to zero. When the delay associated with one of the block units of the incoming stream is not equal to zero, the control unit generates a reading index for reading one of the block units stored in the data buffer, controls the output unit to output the block unit read from the data buffer, generates a writing index, and stores the block unit of the incoming stream in the respective one of the lines of the data buffer in accordance with the writing index. A method for interleaving the same is also disclosed.

Method and apparatus for interleaving an incoming stream of data blocks

A digital-to-analog converting method operating under two clock signals of different periods is disclosed. The method includes steps of monitoring a phase relationship between the two clock signals; starting transmission of a plurality of pre-stored series of waveform samples in response to each rising edge of the first clock signal, wherein a phase difference is present between every two adjacent series of waveform samples; outputting the waveform samples of each series in response to rising edges of the second clock signal; and selecting one of the plurality of pre-stored sets of waveform samples to be converted into an analog signal according to the phase relationship. The various pre-stored series of waveform samples having therebetween phase differences are optionally used for phase compensation so as to reduce the clock jitter between the two clock signals. A digital-to-analog converter for implementing the above-mentioned method is also disclosed.

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Hsinchu, Taiwan

Ching-Kae Tzou