According to one embodiment, an equalizer circuit includes a nonlinear equalizer including: a determination circuit configured to generate a second signal indicating a digital value of a first signal, based on a first clock signal; a clock generation circuit configured to generate a second clock signal having a time constant of a falling edge larger than a time constant of a rising edge, based on the first clock signal; and a feedback circuit configured to generate a third signal by feeding back the second signal to the first signal, based on the second clock signal.

The present invention relates to precoding and feedback channel information in wireless communication system. A method includes receiving a first Precoding Matrix Index (PMI) and a second PMI from a terminal; mapping one or two codewords into layers; precoding symbols mapped into the layers using a first precoding matrix derived from the first PMI and a second precoding matrix derived from the second PMI; and transmitting the precoded symbols to the terminal, wherein the reception of the first PMI is less frequent than the reception of the second PMI.

A jones matrix is obtained using coefficients of an equalizer; a parameter of the jones matrix is obtained; a coefficient of an X axis polarization state or a Y axis polarization state in the coefficients is adjusted using the parameter of the jones matrix when the coefficients have singularity characteristics, or energy corresponding to each coefficient of X or Y axis polarization state under each order of a filter in the equalizer is determined using two coefficients of an X or Y axis polarization state in the equalizer coefficients; and a central position of a coefficient tap of X or Y axis polarization state of the equalizer is adjusted using the energy corresponding to each coefficient of X or Y axis polarization state under each order of the filter when the coefficient tap of the X axis or Y axis polarization state of the equalizer deviates from the central position.

According to one embodiment, an equalizer circuit includes a nonlinear equalizer including: a determination circuit configured to generate a second signal indicating a digital value of a first signal, based on a first clock signal; a clock generation circuit configured to generate a second clock signal having a time constant of a falling edge larger than a time constant of a rising edge, based on the first clock signal; and a feedback circuit, configured to generate a third signal by feeding back the second signal to the first signal, based on the second clock signal.

Selection of equalization coefficients to configure a communications link between a receiver in a host system and a transmitter in an optical or electrical communication module is performed by a management entity with access to management registers in the receiver and transmitter. Continuous modification of the selected equalization coefficients is enabled on the communications link after the communications link is established to handle varying operating conditions such as temperature and humidity.

A first communication device receives a sounding packet that was transmitted by a second communication device over a communication channel, and performs a channel estimation on a subchannel block of the communication channel to determine steering matrix feedback information for the subchannel block. The subchannel block spans a contiguous partial bandwidth of the communication channel and does not span an entire bandwidth of the communication channel. The first communication device transmits a communication frame to the second communication device, the communication frame i) including the steering matrix feedback information for the subchannel block, and ii) not including steering matrix feedback information for the one or more other subchannel blocks of the communication channel.

All data symbols used in data transmission of a modulated signal are precoded by hopping between precoding matrices so that the precoding matrix used to precode each data symbol and the precoding matrices used to precode data symbols that are adjacent to the data symbol in the frequency domain and the time domain all differ. A modulated signal with such data symbols arranged therein is transmitted.

A transmitter for providing channel equalization that includes a first driver and second driver having a high pass filter. The first driver generates a first output signal representing a digital input signal. The second driver generates a second output signal representing a high pass filtered version of the digital input signal. The first and second output signals are summed to provide a third output signal that is channel equalized for transmission over a channel.

The present invention relates to precoding and feedback channel information in wireless communication system. A method includes receiving a first Precoding Matrix Index (PMI) and a second PMI from a terminal; mapping one or two codewords into layers; precoding symbols mapped into the layers using a first precoding matrix derived from the first PMI and a second precoding matrix derived from the second PMI; and transmitting the precoded symbols to the terminal, wherein the reception of the first PMI is less frequent than the reception of the second PMI.

According to an embodiment, a control circuit of an equalizer configured to set a first amount to a linear equalizer, determine a second amount optimizing a non-linear equalizer with respect to a first signal generated by the linear equalizer to which the first amount is set, set the second amount to the non-linear equalizer, update an amount from the first amount to a third amount smaller than the first amount based on a magnitude of the first amount, set the third amount to the linear equalizer, determine a fourth amount optimizing the non-linear equalizer with respect to a second signal generated by the linear equalizer to which the third amount is set, and update an amount from the second amount to the fourth amount.