Abstract: The described techniques relate to improved methods, systems, devices, and apparatuses that support spatial reuse for sidelink communications. Generally, the described techniques provide for a user equipment (UE) to reuse resources for receiving sidelink transmissions. The UE may receive a first sidelink control channel that may indicate a set of reserved resources for sidelink communications associated with a second UE. The first UE may decode a second sidelink control channel from the second UE based on the first sidelink control channel. The first UE may determine that the set of resources is available for use based on a result of decoding the second sidelink control channel, a radius of the second sidelink control channel, and the distance between the first UE and the second UE.

Abstract: Methods, systems, and devices for wireless communications are described for improving sidelink communication reliability. In some examples, a user equipment (UE) may map allocated sidelink resources from a logical domain to a physical domain, where the mapped resources may include greater frequency diversity in the physical domain A frequency range of a sidelink control channel or of a sidelink data channel may be greater in the physical domain than in the logical domain after the mapping. In some examples, sidelink communications may be associated with an aggregation factor that represents a number of repetitions of a sidelink communication. In this example, a UE may repeat a sidelink communication within a contention-based resource pool a number of times before receiving feedback in order to increase communication reliability. A first UE may communicate a sidelink communication with a second UE using a resource mapping or repetitions of the sidelink communication.

Abstract: 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, a grant-only indicator to indicate that a second stage sidelink control information (SCI-2) is decoupled from physical sidelink shared channel (PSSCH) data in a slot, and that the SCI-2 indicates an SCI-2-only grant. The first UE may transmit, to the second UE in the slot, the SCI-2-only grant multiplexed with data-only traffic in a first PSSCH transmission based at least in part on the grant-only indicator, wherein the SCI-2-only grant indicates a resource allocation for a subsequent slot. Numerous other aspects are described.

Abstract: Various aspects of the present disclosure generally relate to wireless communication. In some aspects, a user equipment (UE) may receive a configuration that indicates multiple time intervals corresponding to multiple physical sidelink shared channels (PSSCHs) within a slot, wherein at least one PSSCH, of the multiple PSSCHs, starts in a symbol other than an initial data symbol of the slot. The UE may communicate in one or more PSSCHs, of the multiple PSSCHs, within the slot based at least in part on the configuration. Numerous other aspects are described.

Abstract: Methods, systems, and devices for wireless communications at a device are described. The device may receive an indication of a configuration that schedules semi-persistently scheduled resources for transmissions from the first device. The device may also receive an indication of a set of resources available to the first device for requesting a set of the semi-persistently scheduled resources configured for the first device. The device may transmit a message over the set of resources to request the set of semi-persistently scheduled resources.

Abstract: Methods, systems, and devices for wireless communications are described for improving sidelink communication reliability. In some examples, a user equipment (UE) may map allocated sidelink resources from a logical domain to a physical domain, where the mapped resources may include greater frequency diversity in the physical domain. A frequency range of a sidelink control channel or of a sidelink data channel may be greater in the physical domain than in the logical domain after the mapping. In some examples, sidelink communications may be associated with an aggregation factor that represents a number of repetitions of a sidelink communication. In this example, a UE may repeat a sidelink communication within a contention-based resource pool a number of times before receiving feedback in order to increase communication reliability. A first UE may communicate a sidelink communication with a second UE using a resource mapping or repetitions of the sidelink communication.

Abstract: Certain aspects of the present disclosure provide techniques for uplink transmissions through sidelinks for multi-path diversity. A method that may be performed by a base station (BS) includes configuring one or more groups of user equipments (UEs) of a group of UEs with a configuration of one or more resources. The one or more resources includes one or more sidelink channels between each of the UEs in the group of UEs and an uplink channel between the BS and each of the UEs in the group of UEs. The BS receives data from at least one UE in the group of UEs via at least one of the uplink channels, wherein the data is associated with a different UE.

Abstract: Wireless communications systems and methods related to communicating control information are provided. A method of wireless communication performed by a user equipment (UE) may include performing a clear channel assessment (CCA), transmitting, to a first UE based on the CCA being successful, a first transport block (TB) via a first sub-PSSCH associated with a first sub-slot, and transmitting, to at least one of the first UE or a second UE, a second TB via a PSSCH associated with a slot.

Abstract: Methods, systems, and devices for wireless communications are described. A first device, which may be a user equipment (UE), may transmit a sidelink control information SCI) message (e.g., an SCI-1 message) on a physical sidelink control channel (PSCCH) to a group of devices. The SCI may message may reserve a set of sidelink resources for a sidelink communication between the first device and a second device of the group of devices. The first device may receive an acknowledgment (ACK) message on a physical sidelink feedback channel (PSFCH) from the second device. Based on receiving the ACK message, the first device may release the set of sidelink resources and may transmit a release message (e.g., a physical sidelink release channel (PSRCH) message) on a PSRCH that includes an indication of the released set of sidelink resources.

Abstract: Certain aspects of the present disclosure provide techniques for a fallback retransmission for a sidelink. A method that may be performed by a user equipment (UE) includes monitoring a transmission from a node. The UE can determine that the transmission was not successfully decoded. The UE can send a feedback message to the node indicating that the transmission was not successfully decoded. The feedback message can also include an indication of whether the node or a base station (BS) retransmits the transmission. The node retransmits the transmission or indicates to the BS to retransmit based on the feedback message. The BS can configure the node, the UE, or both with one or more thresholds for determining whether the node or the BS retransmits the transmission.

Abstract: Methods, systems, and devices for wireless communications are described. A first wireless device may receive sidelink control information from a second wireless device. The sidelink control information may include an allocation of a first set of resources for a sidelink transmission from the second wireless device to the first wireless device, along with an indication that schedules a second set of resources for additional sidelink transmissions between the first wireless device and the second wireless device that are scheduled to occur after the sidelink transmission from the second wireless device to the first wireless device. Based on the received indication, the first wireless device may communicate with the second wireless device via a sidelink shared channel using the first set of resources and the second set of resources.

Abstract: A base station receives feedback for a first data transmission or an indication to retransmit a first data transmission, the first data transmission being transmitted to at least one wireless device from another wireless device. The base station transmits, in response to the feedback or the indication, a retransmission of the first data transmission in a downlink transmission to the at least one wireless device.

Abstract: Methods, systems, and devices for wireless communications are described. A first user equipment (UE) may determine a first set of resources for communications over a sidelink communication link between the first UE and a second UE. The first UE may transmit, to the second UE via the sidelink communication link, a first sidelink control information including a reverse sidelink scheduling indicator based on determining the first set of resources. The first UE may additionally transmit, to the second UE via the sidelink communication link, a second sidelink control information indicating a second set of resources for reverse sidelink transmissions from the second UE to the first UE over the sidelink communication link, where transmitting the second sidelink control information is based on transmitting the first sidelink control information. The first UE may receive, from the second UE, a reverse sidelink message in response to transmitting the second sidelink control information.

Abstract: Aspects of the present disclosure provide techniques that help reducing transmission overhead related to sidelink control information (SCI). For example, when a transmitter UE has established a sidelink communication with a receiver UE, the transmitter UE may schedule with at least one semi-persistent scheduling (SPS) process at a first time interval. The transmitter UE may sense whether a resource is available for transmissions to the receiver UE based on decoding an SCI, such as an SCI 0-1 message. The SCI is transmitted at a second time interval that is greater than the first time interval. For example, the second time interval may be a multiple of the first time interval of the at least one SPS process. The second time interval may be flexible and may be increased to reduce the number of SCI messages transmitted in certain time periods in order to reduce communication overhead.

Abstract: This disclosure provides systems, methods, and apparatuses, including computer programs encoded on computer storage media, for wireless communication. In one aspect of the disclosure, a method of wireless communication performed by a user equipment (UE) includes receiving, from a base station, a grant message indicating a set of sidelink resources. The method further includes transmitting multiple unicast messages via multiple subgroups of the set of sidelink resources.

Abstract: Various aspects of the present disclosure generally relate to wireless communication. In some aspects, a first device may receive, from a second device, a sounding reference signal (SRS) prior to a scheduled communication. The first device may transmit, to the second device, an indication that a measurement of the SRS does not satisfy a threshold, if the measurement of the SRS does not satisfy the threshold. The first device may activate, based at least in part on the transmitting the indication and before the scheduled communication, a multi-point communication mode. Numerous other aspects are described.

Abstract: Wireless communications systems and methods related to communicating information are provided. A method of wireless communication performed by a user equipment (UE) may include mapping a sub-physical sidelink shared channel (sub-PSSCH), sidelink control information (SCI), and an automatic gain control (AGC) symbol to a sub-slot of a plurality of sub-slots of a slot and transmitting, to at least one other UE, a transport block via the sub-PSSCH of the sub-slot.

Abstract: Methods, systems, and devices for wireless communications are described in which a first user equipment (UE) may transmit sidelink communications to a second UE, and the second UE may provide feedback associated with the sidelink communication to the first UE in a sidelink control information (SCI) transmission. In some cases, the SCI is first stage SCI transmitted in a sidelink control channel or second stage SCI transmitted in a sidelink shared channel. The feedback may include one or more of acknowledgment/negative-acknowledgment feedback, channel state information feedback, a scheduling request, or any combinations thereof. In some cases, the first UE may indicate resources of the second slot to the second UE for transmission of the feedback in the SCI, such as by providing a time offset value and resource index that identifies the resources.

Abstract: Apparatus, methods, and computer-readable media for facilitating multiplexing SCI-only grant and data-only SPS traffic on sidelink are disclosed herein. An example method for wireless communication at a first UE includes transmitting a sidelink transmission to a second UE at a first resource, the sidelink transmission including data-only traffic and scheduling information corresponding to future data traffic. The example method also includes transmitting a time offset indicator indicating a starting resource of the future data traffic.

Abstract: Apparatus, methods, and computer-readable media for facilitating usage of memory of helping UEs during sidelink retransmission are disclosed herein. An example method for wireless communication at a first user equipment (UE) includes receiving, from a wireless device, a first packet and a second packet for sidelink retransmission to at least one second UE, the second packet being received after the first packet. The example method also includes dropping the first packet or the second packet prior to retransmission based on at least one of a packet priority or an indication from the wireless device.