The present invention provides a multi-rate bidirectional transmission system. A sending device and a receiving device transmit data in a bidirectional way through a cable. The multi-rate bidirectional transmission system communicates with a reverse configuration packet by sending a forward configuration packet at a preset rate in a time-division manner, selects a serial rate jointly supported by the sending device and the receiving device, and selects a training sequence length. Then, the sending device and the receiving device perform equalization training at the selected serial rate with the selected training sequence length, thus avoiding searching the serial rate and presetting the training sequence length in the worst case, thus simplifying the design and improving the link training speed.

An apparatus, method and computer program is described comprising: initialising trainable parameters of a transmission system having a transmitter, a channel and a receiver; generating training symbols on the basis of a differentiable distribution function; transmitting modulated training symbols to the receiver over the channel in a training mode; generating a loss function based on the generated training symbols and the modulated training symbols as received at the receiver of the transmission system; and generating updated parameters of the transmission system in order to minimise the loss function.

A receiver included in a memory device includes a flag generator circuit, an equalizer circuit and an equalization controller circuit. The flag generator circuit is configured to, during a normal operation mode, generates a flag signal without an external command. The equalizer circuit is configured to, during the normal operation mode, receive an input data signal through a channel, generate an equalized signal by equalizing the input data signal based on an equalization coefficient, and generate a data sample signal including a plurality of data bits based on the equalized signal. The equalization controller circuit is configured to, during the normal operation mode, determine an amount of change in the equalization coefficient based on the flag signal, the equalized signal and the data sample signal, and perform a training operation in which the equalization coefficient is updated in real time based on the amount of change in the equalization coefficient.

A communication device communicates a physical (PHY) frame including a preamble and a data field. The preamble includes a Legacy Short Training Field (L-STF), a Legacy Long Training Field (L-LTF), a Legacy Signal Field (L-SIG), an EHT Signal Field (EHT-SIG-A), an EHT Short Training Field (EHT-STF), and an EHT Long Training Field (EHT-LTF) and the EHT-SIG-A includes fields indicating a modulation scheme and information indicating which one of a UC (Uniform Constellation) scheme and an NUC (Non Uniform Constellation) scheme is used as the modulation scheme, and the data field includes data that has undergone modulation corresponding to the modulation scheme and the information indicated by the fields.

An apparatus, method and computer program is described comprising: initialising trainable parameters of a transmission system having a transmitter, a channel and a receiver; generating training symbols on the basis of a differentiable distribution function; transmitting modulated training symbols to the receiver over the channel in a training mode; generating a loss function based on the generated training symbols and the modulated training symbols as received at the receiver of the transmission system; and generating updated parameters of the transmission system in order to minimise the loss function.

A training packet sending method and apparatus, where the method includes generating, by a first device, a training packet, where the training packet includes a preamble, a header, and a training field, and the header includes at least a legacy header, and repeatedly sending, by the first device, the preamble using N channels, sending the legacy header in the header using the N channels, and sending the training field to at least one second device using H channels of the N channels, where N is greater than 1, and H is greater than 1 and less than or equal to N.

A sequence generation method, includes: generating a PPDU which comprises a matrix-mapped EHT LTF sequence, the matrix-mapped EHT LTF sequence is obtained by multiplying a predefined EHT LTF sequence by a P matrix, the P matrix is an n×n matrix, and n is greater than 8; and sending the PPDU, therefore the matrix-mapped EHT LTF sequence in a PPDU has a low PAPR value.

During a training procedure for communicating via a full-duplex communication link, a first communication device receives training information from a second communication device. The training information corresponds to first signal processing parameters developed at the second communication device for use by the second communication device to process signals received by the second communication device via the full-duplex communication link. After receiving the training information from the second communication device, the first communication device develops second signal processing parameters to be used by the first communication device to process signals received by the first communication device via the full-duplex communication link. The second signal processing parameters are developed using the training information received from the second communication device.

The present invention discloses a receive data equalization apparatus. A delay-compensating calculation circuit retrieves training data groups of a training data signal to retrieve total delay amount, generate signed compensation amounts according to a relation among training data contents of training data in each of the training data groups to generate total compensation amount accordingly, and solve equations that correspond total delay amount of the training data groups to the total compensation amount to obtain each of the compensation amounts. A receive data equalization circuit receives the compensation amounts and retrieves a receive data group in a receive data signal, generate signed receive compensation amounts according to a relation among receive data contents of receive data in the receive data group to generate a total receive compensation amount accordingly to perform equalization on a terminal edge of the receive data group according to the total receive compensation amount.

Disclosed retimer modules and methods enable equalizer training during link speed negotiation. One illustrative retimer module includes: an analog to digital converter that uses a sampling clock to digitize a receive signal; an equalizer that converts the digitized receive signal into an equalized signal; a decision element that derives a receive symbol stream from the equalized signal; and a clock recovery module that derives the sampling clock based at least in part on an equalization error of the equalized signal, the sampling clock having a frequency with a range including a baud rate of the receive signal at a first supported speed and including a frequency not less than twice the baud rate of the receive signal at a second supported speed.