A WTRU apparatus and method for operation thereby are provided. The method may comprise receiving, from a network, a mapping rule which indicates HARQ feedback characteristics to employ for a QoS level and a channel load. The WTRU may determine a QoS level of data buffered for transmission and may further determine a channel load of a channel. Based on the QoS level and channel load, HARQ feedback characteristics may be determined. The WTRU may then transmit an SCI to another WTRU which indicates the HARQ feedback characteristics. In an embodiment, the mapping rule may indicate that a HARQ feedback format is to be used for HARQ feedback of the data. The data may be transmitted and HARQ feedback of the data may be received in accordance with the HARQ feedback format. Groupcast data may be transmitted to a plurality of WTRUs and feedback my be received.

Various aspects of the present disclosure generally relate to wireless communication. In some aspects, a first user equipment (UE) may receive, from a second UE via a sidelink interface, a triggering signal associated with triggering hybrid automatic repeat request (HARQ) feedback for a sidelink. The UE may transmit, to the second UE and based at least in part on the triggering signal, HARQ feedback associated with the second UE. Numerous other aspects are provided.

Various aspects of the present disclosure generally relate to wireless communication. In some aspects, a first user equipment (UE) may receive, from a second UE, information via a sidelink interface between the first UE and the second UE. The UE may transmit, to the second UE, sidelink hybrid automatic repeat request acknowledgement feedback using a sidelink feedback channel resource of a sidelink resource pool via a sidelink component carrier based at least in part on the information received from the second UE. Numerous other aspects are provided.

A data transmission method includes: receiving, by a user equipment (UE), first indication information from a wireless access device, where the first indication information is activation indication information or deactivation indication information; and when the first indication information is the activation indication information, executing, by the UE, a processing operation; or when the first indication information is the deactivation indication information, stopping, by the UE, the processing operation; where the processing operation includes at least one of a duplication operation and a switching operation; the duplication operation means transmitting same data through a plurality of links; and the switching operation means selecting one from a plurality of links to perform data transmission.

A user equipment includes a receiving unit configured to receive a configuration of a resource pool; a communicating unit configured to receive a physical control channel and a physical shared channel in the resource pool; a control unit configured to determine whether a response relating to retransmission control associated with the resource pool is enabled or disabled, based on the configuration of the resource pool; and a transmitting unit configured to transmit the response relating to the retransmission control with respect to the received physical shared channel, upon determining that the response relating to the retransmission control is enabled.

Methods, systems, and devices for wireless communications are described. A first user equipment (UE) may receive, from a second UE, a first control signal indicating a range value corresponding to a threshold distance for triggering feedback reporting from the first UE for transmissions from the second UE. The first UE may calculate a traversable distance corresponding to a traversable route between the first UE and the second UE, determine, based on the calculated traversable distance and the range value, whether the first UE is within the threshold distance for triggering feedback reporting, and perform, based on whether the first UE is within the threshold distance, a feedback procedure for the feedback reporting. The first UE may receive, from the second UE, a second control signal indicating a type of distance measurement corresponding to the threshold distance for triggering feedback reporting.

Provided are methods and apparatuses for transmitting and/or receiving sidelink HARQ feedback information. Further, a method of a user equipment (UE) may be provided for transmitting HARQ feedback information in response to sidelink transmission. The method may include: receiving configuration information for a resource pool for the sidelink transmission, receiving configuration information on frequency resources for transmission of a physical sidelink feedback channel (PSFCH) in the resource pool, and transmitting HARQ feedback information in response to a physical sidelink shared channel (PSSCH) received from one or more other UE(s) using a PSFCH resource determined based on the configuration information for frequency resources in the resource pool.

A method by which a first device performs wireless communication is presented. The method can comprise the steps in which: a first device performs at least one sidelink transmission to a second device; negative acknowledgement (NACK) information related to the at least one sidelink transmission is received from the second device; and whether to transmit a message for requesting a retransmission resource is determined on the basis of a preset latency time threshold value and a remaining latency budget related to the at least one sidelink transmission.

A communication apparatus includes a control unit that separately defines, for unicast and for groupcast, a Hybrid Automatic Repeat Request (HARQ) process number and a New Data Indicator (NDI) used for sidelink HARQ processing; and a transmitting unit that transmits sidelink control information including the HARQ process number and the NDI defined for the unicast, or including the HARQ process number and the NDI defined for the groupcast.

Example methods and apparatus for determining a transport block size are described. One example method includes determining a transport block size (TBS) of a first transport block by a communications apparatus. The communications apparatus determines a TBS of a second transport block based on the TBS of the first transport block, where the first transport block is different from the second transport block, the TBS of the second transport block is equal to the TBS of the first transport block, and a data channel carrying the first transport block and a data channel carrying the second transport block occupy a same time domain resource.