Abstract: An automated optical double-sided inspection apparatus includes a first image-capturing portion, a second image-capturing portion, a platform, a first light-blocking portion, a second light-blocking portion, and a processing portion. The platform carries an external object. When the processing portion operates in a first capturing mode, the second light-blocking portion blocks visible light from passing therethrough, while the first light-blocking portion allows visible light to pass therethrough, so that the first image-capturing portion shoots a first side of the external object through the first light-blocking portion to obtain a first image.

Abstract: Embodiments of this application disclose a communication method, to optimize a channel access parameter. The method includes: A first station sends a request frame to an access point. The request frame is used to request to obtain a channel priority access right. The request frame carries a first parameter set. The first parameter set includes MU EDCA parameters that the first station intends to use to perform channel contention. The first station receives a response frame for the request frame. The first station is an EPCS station. The first station performs channel access by using an MU EDCA mechanism. In embodiments of this application, the first parameter set includes the MU EDCA parameters that the first station intends to use to perform channel contention. The request frame carrying the first parameter set is sent. In this way, channel contention is performed by using parameters with a higher channel access priority.

Abstract: This application provides a communication method and a related apparatus. The method includes: generating and sending a PPDU, where the PPDU includes a first signal field, the first signal field includes a resource unit allocation subfield and at least one user field corresponding to each user, the resource unit allocation subfield indicates a frequency domain resource allocated to the user corresponding to each user field, the user corresponding to each user field includes a first user that uses joint source and channel coding, the PPDU further includes a second signal field of the first user that uses joint source and channel coding, the second signal field of the first user indicates a joint source and channel coding parameter of a source layer corresponding to the first user, and the second signal field of the first user is located on a frequency domain resource allocated to the first user.

Abstract: The technology of this application relates to methods and apparatuses for sending and receiving a physical layer protocol data unit. The method includes generating a physical layer protocol data unit (PPDU), where the PPDU includes a short training field, a length of a frequency domain sequence of the short training field is greater than a first length, and the first length is a length, for example, 2048, of a frequency domain sequence of a short training field that is transmitted over a 160 MHz-bandwidth channel. The method further includes sending the PPDU over a target channel, where a bandwidth of the target channel is greater than 160 MHz. According to embodiments of this application, a larger actual channel bandwidth can be achieved, and backward compatibility is implemented.

Abstract: This application relates to spatial reuse methods and devices. An example method includes: receiving a physical layer protocol data unit (PPDU) sent by a device, where a bandwidth of the PPDU includes a plurality of 20 megahertz (MHz) subchannels; and performing overlapping basic service set packet detection (OBSS PD)-based spatial reuse, where a first signal strength level of the received PPDU is less than an OBSS PD level, and a unit of the first signal strength level is decibel-milliwatt (dBm)/20 MHz.

Abstract: A bandwidth information indication method includes generating, by a first communications device, a first frame, where the first frame includes a channel bandwidth field, a first channel center frequency segment field, a second channel center frequency segment field, a third channel center frequency segment field, and a fourth channel center frequency segment field, where the channel bandwidth field indicates a basic service set (BSS) bandwidth, and the first channel center frequency segment field, the second channel center frequency segment field, the third channel center frequency segment field, and the fourth channel center frequency segment field indicate a location of an operating channel of a BSS, and sending, by the first communications device, the first frame.

Abstract: This disclosure discloses puncturing information indication methods and communication apparatuses. In an implementation, a method comprises generating a physical layer protocol data unit (PPDU) comprising a preamble, wherein the preamble comprises a universal-SIG (U-SIG) field, wherein the U-SIG field comprises mode indication information and preamble puncturing status indication information, and wherein the preamble puncturing status indication information indicates a preamble puncturing status corresponding to a mode indicated by the mode indication information, and sending the PPDU.

Abstract: A self-piercing riveting system includes a localized melting system that locally melts a target location on a metal substrate and a driver that drives a rivet into to the metal substrate after the target location is locally melted. A method of forming a joint with a self-piercing riveting system includes locally melting a target location on the at least two metal substrates. The method also includes driving a rivet into the target location, optionally with a driver, after locally melting the target location such that the rivet pierces the at least two metal substrates at the target location.

Abstract: A communication method is applied to a wireless local area network in an enhanced multi-link single radio (EMLSR) mode. When an enhanced multi-link single radio (EMLSR) non-access point multi-link device (non-AP MLD) finds that states of all or some links of the EMLSR non-AP MLD change, the EMLSR non-AP MLD sends a frame on any available link. The frame carries indication information indicating an available link or a link whose state changes in the EMLSR non-AP MLD. Alternatively, the frame may carry another piece of indication information indicating that a state of a link has changed. An access point multi-link device (AP MLD) refrains from sending a signal to the EMLSR non-AP MLD on an unavailable link of the EMLSR non-AP MLD.

Abstract: An access point receives restricted target wake time setup request information sent by a station. The restricted target wake time setup request information is used to request to set up a restricted target wake time. The access point sends restricted target wake time response information to the station. The restricted target wake time response information is used to respond to the restricted target wake time setup request information. The restricted target wake time setup request information or the restricted target wake time response information includes indication information of a first access category corresponding to low-latency traffic of the station. The station or the access point can independently and selectively configure the access category for the low-latency traffic.

Abstract: This application provides a communication method and a communication apparatus. The method includes: A sending device sends a first physical layer protocol data unit PPDU over a first link, where the first PPDU carries a trigger frame. The sending device sends a second PPDU over a second link, where the second PPDU carries a second trigger frame; and an absolute value of a time difference between an end time of sending the first PPDU and an end time of sending the second PPDU is less than or equal to a first duration, and the first duration is related to a state turnaround time in a short interframe space (SIFS) time.

Abstract: A method in the field of networking technologies for sending a wake up packet, an apparatus, and a device. The method for sending a wake up packet is applied to a first node, wherein the first node maintains a first contention window (CW1) on a first channel, the first channel is a channel on which a main transceiver of a second node works, and the method includes generating a backoff count based on CW1, executing backoff based on the backoff count, and sending a wake up packet to the second node on a second channel when backoff ends, wherein the second channel is a channel on which a wake up receiver of the second node works.

Abstract: This application discloses a multi-link communication method and apparatus. The method includes: A transmitter sends a first A-MPDU, and a receiver receives the first A-MPDU. The receiver obtains a locally recorded scoreboard context, and when the first A-MPDU meets at least one of the following conditions: a first condition, a second condition, a third condition, or a fourth condition, the receiver refreshes the scoreboard context based on an SN of the first A-MPDU. According to the method provided in this application, the receiver can properly and effectively refresh the local scoreboard context, to ensure that the receiver correctly feeds back receiving statuses of all MPDUs in an A-MPDU received by the receiver.

Abstract: A channel sounding method and a channel sounding apparatus are disclosed. The method includes: A first communication apparatus sends a null data packet announcement (NDPA) frame, and sends a null data packet (NDP); and a second communication apparatus and a third communication apparatus receive the NDPA frame and the NDP.

Abstract: A method for sending a wireless local area network packet structure is provided, and the method comprises: determining a packet structure, where the packet structure comprises an HE-SIGA and an HE-SIGB, the HE-SIGA comprises an indication information, and if a current transmission mode is a full bandwidth MU-MIMO transmission, the indication information is used to indicate a number of scheduled users, or if the current transmission mode is other transmission mode, the indication information is used to indicate a number of symbols in the HE-SIGB; and sending the packet structure.

Abstract: A data transmission method includes generating a signaling field of a PPDU, where a channel bandwidth for transmitting the PPDU includes at least two frequency segments, which include a first frequency segment, and the channel bandwidth includes an RU for MU-MIMO transmission; the signaling field includes a common field and a user-specific field, the user-specific field includes a user field corresponding to the RU, and the user field is a user field of a station to which the RU is allocated and that parks on the first frequency segment; and the common field includes a resource unit allocation subfield corresponding to the RU, indicating the RU and a quantity of user fields corresponding to the RU; and sending the signaling field on the first frequency segment. Some embodiments are applied to a WLAN system that supports 802.11be standard.

Abstract: This application relates to the field of wireless communication, and in particular, to a multi-channel hybrid transmission technology. In an embodiment, a data transmission method comprises: generating, by a first wireless communications device, a physical protocol data unit (PPDU), wherein the PPDU comprises a legacy short training field (L-STF), a legacy long training field (L-LTF), a legacy signal field (L-SIG), and two signature symbols after the L-SIG in a time-domain, and wherein the two signature symbols are identical and are modulated based on binary phase shift keying (BPSK), the two signature symbols identify a wireless communications standard the PPDU complies with; and transmitting, by the first wireless communications device, the PPDU to a second wireless communications device.

Abstract: Embodiments of this application provide a probe request and response technology between a station and a plurality of access point multi-link devices (AP MLDs). During implementation of this application, a station may obtain communication parameters of a plurality of APs of one or more AP MLDs by sending one probe request frame, to obtain communication parameters of the AP MLD on a plurality of links, thereby efficiently implementing association between the station and the AP MLD or establishing multi-link transmission between the station and the AP MLD.

Abstract: Embodiments of this application provide a multi-link communication method and a multi-link device. The multi-link device respectively receives a first A-MPDU and a second A-MPDU over a first link and a second link, where the first A-MPDU and the second A-MPDU have a same traffic identifier, and the first A-MPDU is received before the second A-MPDU. The method includes: The multi-link device determines a start sequence number or an end sequence number of a scoreboard on the first link based on the first A-MPDU received over the second link; and the multi-link device sends a first block acknowledgment frame over the first link based on the start sequence number or the end sequence number of the scoreboard on the first link and the received second A-MPDU, where the first block acknowledgment frame is used to acknowledge a receiving status of the second A-MPDU.

Abstract: This disclosure discloses puncturing information indication methods and communication apparatuses. In an implementation, a method comprises generating a physical layer protocol data unit (PPDU) comprising a preamble, wherein the preamble comprises a universal-SIG (U-SIG) field, wherein the U-SIG field comprises mode indication information and preamble puncturing status indication information, and wherein the preamble puncturing status indication information indicates a preamble puncturing status corresponding to a mode indicated by the mode indication information, and sending the PPDU.