Various aspects of the present disclosure generally relate to wireless communication. In some aspects, a first user equipment (UE) may transmit, to a second UE, an initial transmission of a transport block via a sidelink unlicensed band. The UE may receive, from the second UE, a negative acknowledgement (NACK) based at least in part on the initial transmission of the transport block. The UE may transmit, to the second UE and based at least in part on the NACK and a retransmission reservation, a retransmission of the transport block via the sidelink unlicensed band in a retransmission occasion of a plurality of retransmission occasions associated with the retransmission reservation. Numerous other aspects are described.

A method to reduce a probability of occurrence of a hidden node in a data transmission process in a high-frequency system is disclosed. The method implemented by a communications apparatus includes determining at least one beam to be used for sending a resource reservation message, where the at least one beam includes a first beam, where a direction of the first beam is opposite to a direction of a second beam, and where the direction of the second beam is a potential transmission direction in which the communications apparatus sends information. The method further includes sending the resource reservation message by using the at least one beam, where the resource reservation message includes a resource reservation request message or a resource reservation response message, where the resource reservation request message is used to request to reserve a transmission resource, and where the resource reservation response message is used to determine to reserve a transmission resource.

A method for processing LBT monitoring failures, a method for transmitting preambles, apparatuses thereof and a system. The method for processing LBT monitoring failures includes: a physical layer of a terminal equipment performs LBT monitoring, and indicates an LBT monitoring failure or random access preamble transmission drop or an LBT detection instance failure to an MAC layer or an RRC layer when the physical layer deems that the LBT monitoring fails; and the MAC layer or RRC layer of the terminal equipment performs at least one piece of the following processing according to the indication: performing resource selection; triggering channel selection or BWP switching; triggering a radio link failure; triggering RRC connection reestablishment; and performing counter maintenance.

A wireless local area network (WLAN) protocol allowing a Transmit Opportunity (TXOP) holder to share the TXOP with other stations. An intent to share the TXOP is communicated to the Access Point (AP). Upon gaining channel access, the TXOP holder directly or indirectly communicates that the TXOP can be shared with other STAs, after which scheduling information (time and duration) are shared with the STAs. When the TXOP occurs, the STAs can access the channel at the time and for the duration specified, thus providing increased use of the TXOP to improve efficiency.

The present invention discloses a method for a base station to transmit a radio link monitoring-reference signal (RLM-RS) in an unlicensed band. In particular, the method may divide a frequency band for the RLM-RS into a plurality of sub-bands, perform a channel clearance assessment (CCA) for each of the plurality of sub-bands, and transmit the RLM-RS via each of the plurality of sub-bands on the basis of the result of performing the CCA.

An enhanced LBT procedure (200) mitigates unnecessary delays in delivering transmissions between User Equipment and base stations over unlicensed spectrum. A UE or base station selects a particular CAPC corresponding to an intended transmission (225) based on an intelligent mapping of different types of transmission payload (e.g., transmission payload other than or in in addition to pre-defined, QoS-related UP message data payload) to different CAPCs. Most (if not all) of the mapped CAPCs corresponding to the different types of transmission payload are of a higher priority than a lowest priority CAPC (212-222), resulting in channel access procedures that are more commensurate with respective transmission payloads. The intelligent mapping may indicate different priorities among different types of transmission payload and/or different types of messages, and/or may indicate which type of transmission is to govern selection of a CAPC when multiple types of transmission payload are included in a single, intended transmission.

Embodiments of a method and an apparatus for multi-link data transmission are disclosed. In an embodiment, a method of multi-link communications involves at a first MLD that supports a first link, link1, and a second link, link2, transmitting a first frame during a first Transmission Opportunity (TXOP) on link1, and a second frame during a second TXOP on link2, simultaneously to a second MLD, receiving, at the first MLD, a first response frame to the first frame transmitted on link1 after a transmission end time of the first frame, identifying, at the first MLD, that a response frame to the second frame transmitted on link2 was not received after the transmission end time of the second frame, and transmitting, at the first MLD, a third frame on link1 and a fourth frame on link2 simultaneously, after receiving the first response frame on link1.

Methods, systems, and devices for dynamic monitoring modes for synchronization signal block (SSB) transmissions are described. A user equipment (UE) may monitor one or more first SSB transmission opportunities for SSB transmissions from a base station and determine an SSB failure rate. Based on the failure rate, the UE may select a mode for monitoring one or more second SSB transmission opportunities. For example, if the failure rate is greater than a threshold, the UE may select a first mode for monitoring a first quantity of the one or more second SSB transmission opportunities. Additionally, if the failure rate is less than the threshold, the UE may select a second mode for monitoring a second quantity different than the first quantity of the one or more second SSB transmission opportunities. The UE may monitor the one or more second SSB transmission opportunities according to the selected mode for monitoring.

Technology-specific listen before talk (LBT) parameter adjustments are disclosed for common energy detection (ED) thresholds. Some of the technologies sharing access to the same shared communication spectrum include additional access deferral procedures. Such technologies may be configured with additional compensating features to increase the likelihood of fairness in spectrum access across all technologies sharing a common ED threshold. Such additional compensating features may include a reduced contention window size relative to the technologies that do not include such additional access deferral procedures, increased maximum channel occupancy times (COTs) for longer transmissions, and the like. Each such additional compensating feature may be available under different circumstances, such as always available or available in response to the node activating one of the additional access deferral procedures. Additionally, such additional compensating features may, once initiated, be active and available for a predetermined period of time.

A data transmission method and a communication device are provided. Regarding the synchronization transmission of a plurality of transmission connections, in response to at least two of the plurality of transmission connections having different random backoff parameters, a frame length of a message frame transmitted by each transmission connection is determined based on a maximum random backoff parameter of the plurality of transmission connections.