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.

Apparatus and associated methods relate to using a high learning rate to speed up the training of a receiver and switching from a high learning rate to a low learning rate for fine tuning based on exponentially weighted moving average convergence. In an illustrative example, a selection circuit may switch the high learning rate to the low learning rate based on a comparison of a moving average difference e.sub.n to a predetermined stability criteria T.sub.1 of the receiver. The moving average difference e.sub.n may include an exponentially weighted moving average of a difference between two consecutive exponentially weighted moving averages of an operation parameter u.sub.n of the signal communication channel. By using this method, the training time for the receiver may be advantageously reduced.

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.

A communication device includes a receiver configured to receive a signal, a sampler configured to sample the signal for each digital value of the predefined sequence of digital values in the signal, a memory configured to store a table giving, for each of a plurality of combinations of one or more preceding first digital values and a following second digital value, a threshold for a signal level to detect the second digital value, an initializer configured to, for a combination in a subset of the plurality of combinations, initialize the table based on a sample of the signal for the second value, and for a combination outside of the subset, select a combination from the subset and initialize the table based on a sample of the signal for the second value of the selected combination.

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.

One or more link training signals are received, including instances of a link training pattern, on a plurality of lanes of a physical link that includes at least one valid lane and a plurality of data lanes. The plurality of lanes are trained together using the link training signals to synchronize sampling of the valid lane with sampling of the plurality of data lanes. An active link state is entered and a valid signal received on the valid lane during the active link state. The valid signal includes a signal held at a value for a defined first duration and indicates that data is to be received on the plurality of data lanes in a second defined duration subsequent to the first duration. The data is to be received, during the active link state, on the plurality of data lanes during the second defined duration.

In performing SVD-MIMO transmission, a set-up procedure is simplified while assuring a satisfactory decoding capability with a reduced number of antennas. A transmitter estimates channel information based on reference signals sent from a receiver, determines a transmit antenna weighting coefficient matrix based on the channel information, calculates a weight to be assigned to each of components of a multiplexed signal, and sends, to the receiver, training signals for respective signal components, the training signals being weighted by the calculated weights. On the other hand, the receiver determines a receive antenna weighting coefficient matrix based on the received training signals.

A secure training sequence (STS) is included in wireless packets communicated between electronic devices to assist with channel estimation and wireless ranging. The STS includes multiple STS segments generated based on outputs from a cryptographically secure pseudo-random number generator (CSPRNG), the STS segments being separated by guard intervals and formatted in accordance with an 802.15.4 data symbol format that uses burst position modulation (BPM) and binary phase shift keying (BPSK) to map bits from the CSPRNG to burst positions and pulse polarities for the STS symbols. Both a first electronic device, which generates the STS, and a second electronic device, which estimates a communication channel using the STS, have prior private knowledge of cryptographic keys required to generate a non-repetitive single-use pseudo-random (PR) sequence by the CSPRNG. The STS includes two burst position intervals per STS symbol and two possible burst positions within each burst position interval.

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.