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.

A first communication device generates a beamforming training initiator packet for transmission in a wireless communication network. The beamforming training initiator packet indicates a start of a beamforming training session, and includes a plurality of fields that respectively and individually identify multiple second communication devices that are to process beamforming training packets transmitted by the first communication device during the beamforming training session. The first communication device transmits the beamforming training initiator packet, and then transmits a plurality of beamforming training packets during the beamforming training session.

An optical transmission method for processing a signal based on direct detection includes setting, by an equalizer, an adaptive equalization coefficient by performing an equalization process during a training symbol field section in a frame of a received signal, performing, by a channel estimator, channel estimation to perform an equalization process of a soft output maximum likelihood sequence equalizer (MLSE) during the training symbol field section, driving the soft output MLSE, and compensating for, by the soft output MLSE, distortion of the received signal during a data symbol field section in the frame on the basis of the adaptive equalization coefficient and an estimated result value of a channel, and recovering, by an error corrector which allows soft-decision processing to be performed, the received signal by performing error correction on the received signal in which the distortion is compensated for.

An optical transmission method for processing a signal based on direct detection includes setting, by an equalizer, an adaptive equalization coefficient by performing an equalization process during a training symbol field section in a frame of a received signal, performing, by a channel estimator, channel estimation to perform an equalization process of a soft output maximum likelihood sequence equalizer (MLSE) during the training symbol field section, driving the soft output MLSE, and compensating for, by the soft output MLSE, distortion of the received signal during a data symbol field section in the frame on the basis of the adaptive equalization coefficient and an estimated result value of a channel, and recovering, by an error corrector which allows soft-decision processing to be performed, the received signal by performing error correction on the received signal in which the distortion is compensated for.

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.

According to one embodiment, a communication device includes a control circuit. The control circuit determines an output waveform of the data to be received from an external device. The control circuit stores information relating to the output waveform into a nonvolatile memory in response to determining of the output waveform of the data from among N (N is a natural number of three or more) types of output waveforms. The control circuit determines an output waveform of the data from among M or less types of output waveforms in the N types of output waveforms (M<N) (M is a natural number of N2 or more) based on the information stored in the nonvolatile memory, when the information is stored in the nonvolatile memory.

A primary transmitter of a multicast communication system transmits in-band backhaul to a relay transmitter using an LDM signal that also carries services to end-users. The relay transmitter processes received wireless signal to extract the in-band backhaul and re-transmits services obtained from the in-band backhaul in same or different frequency channel. The in-band backhaul may be transmitted in a high-capacity layer of the LDM signal carrying or in a separate timeslot. Transmitter-specific signature signals may be used for loopback and forward channel estimation at the relay transmitter. The in-band backhaul may also carry service data for devices in a different network.

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.

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.