The present disclosure is directed to systems, apparatuses, and methods for performing continuous or periodic link training. Existing link training protocols generally perform link training only once during startup or initialization of a link and, as a result, are limited in their applications. After link training is performed and Open Systems Interconnect (OSI) data link layer and other high-layer data is transmitted across the link, no further link training is performed using these existing link training protocols. However, parameters of the link may change over time after link training is performed, such as temperature of the link and voltage levels of signals transmitted over the link by the transmitter of the transmitter-receiver pair.

The present disclosure is directed to systems, apparatuses, and methods for performing continuous or periodic link training. Existing link training protocols generally perform link training only once during startup or initialization of a link and, as a result, are limited in their applications. After link training is performed and Open Systems Interconnect (OSI) data link layer and other high-layer data is transmitted across the link, no further link training is performed using these existing link training protocols. However, parameters of the link may change over time after link training is performed, such as temperature of the link and voltage levels of signals transmitted over the link by the transmitter of the transmitter-receiver pair.

This application provides a training sequence transmission method and apparatus. The method includes: A first AP broadcasts a trigger frame, where the trigger frame indicates a time sequence of separately sending channel sounding frames by N STAs, and N is an integer greater than 1. The first AP receives the channel sounding frames sequentially sent by the N STAs, where one channel sounding frame includes one or more training sequences. In this solution, only one trigger frame needs to be sent, so that the N STAs can be triggered to separately report channel sounding frames to M+1 APs. However, in the conventional technology, each AP needs to send one channel training request to each STA, that is, N?(M+1) channel training requests are sent in total, to trigger each STA to report a training sequence. Therefore, this solution can significantly reduce signaling overheads.

A device for mitigating a first group delay of a lowpass filter configured to lowpass filter a first channel coefficient of a set of channel coefficients with respect to time, includes a prediction filter configured to filter a data sequence derived from a lowpass filtered first channel coefficient to generate a prediction value of the lowpass filtered first channel coefficient; and an adjustment circuitry configured to adjust the prediction filter to generate the prediction value having a second group delay that is less than the first group delay.

A radio access network node, or nodes, may determine learning model configuration information to use to train a learning model corresponding to a user equipment in idle mode. A node may broadcast a training configuration resource indication in an information block indicative of a resource usable to broadcast a learning model training configuration or indicative of a resource usable to broadcast a training result. While idle, a user equipment may decode a training configuration according to the training configuration resource indication and perform a training action indicated in the training configuration. A learning model may be trained, based on the training action, while the user equipment is idle. While idle, the user equipment may use a model trained while the user equipment is idle to estimate a radio parameter and transmit the estimated radio parameter to a node to be used to establish a connection with the node.

A method for receiving a signal by a station (STA) in a wireless LAN system according to an embodiment of the present invention comprises the steps of: receiving a multi-user (MU) frame including a SIG-A field, a SIG-B field and a short training field (STF), and a long training field (LTF) that provides training symbols; and performing blind-decoding of the SIG-B field using a group ID assigned to the STA, wherein the SIG-B field includes information on the number of streams assigned to each of multiple stations that receive the MU frame, and the starting position of a training symbol interval for the STA in the LTF is implicitly indicated by the number of streams assigned to each of other stations in the same group, which share the group ID with the STA, and the order in which the streams are assigned to the STA in the same group.

Embodiments of this disclosure provide an apparatus and method for estimating a frequency offset, an apparatus and method for estimating a channel spacing and a system. The apparatus for estimating a frequency offset includes: a synchronization extracting unit configured to perform a training sequence synchronization extraction on a receiving sequence containing a periodic training sequence to obtain the training sequence; a delay correlation processing unit configured to parallelly perform autocorrelation operations of different delay amounts on the training sequence to obtain multiple parallel correlation sequences; a superimposition processing unit configured to perform a superimposition operation on the multiple parallel correlation sequences to obtain a single sequence; and a frequency offset estimating unit configured to determine a frequency offset according to a phase of a synchronization position of the single sequence in the training sequence. With the embodiments of this disclosure, anti-noise characteristic of the frequency offset estimation may be improved.

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.

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.

A first apparatus obtains data; determines an index of the data based on a first encoding network and a first data codebook, where the first encoding network is for encoding the data, and the first data codebook includes a correspondence between encoded data and the index; and sends information about the index of the data.