WO2021212254A1

WO2021212254A1 - Hop-based channel occupancy time (cot) sharing

Info

Publication number: WO2021212254A1
Application number: PCT/CN2020/085522
Authority: WO
Inventors: Jing Sun; Xiaoxia Zhang; Changlong Xu; Ozcan Ozturk; Yisheng Xue; Chih-Hao Liu
Original assignee: Qualcomm Incorporated
Priority date: 2020-04-20
Filing date: 2020-04-20
Publication date: 2021-10-28

Abstract

This disclosure provides systems, methods, and apparatus, including computer programs encoded on computer storage media, for hop-based channel occupancy time (COT) sharing. In one aspect, a first device, such as a user equipment (UE), may receive a sidelink control message from a second device. The sidelink control message may include sharing information for a COT of a communication link. The first device may determine whether further sharing of the COT is supported based on the sidelink control message. For example, if sharing of the COT is supported, the first device may transmit an additional sidelink message in the COT, such as data to a third device or feedback to the second device. In some examples, multiple UEs may share a same COT using multi-hop COT sharing. Sidelink COT sharing may be based on a sharing indicator, a hop counter, a distance threshold, a group index, or any combination thereof.

Description

HOP-BASED CHANNEL OCCUPANCY TIME (COT) SHARING

TECHNICAL FIELD

This disclosure relates to wireless communications and to hop-based channel occupancy time (COT) sharing.

DESCRIPTION OF THE RELATED TECHNOLOGY

Wireless communications systems are widely deployed to provide various types of communication content such as voice, video, packet data, messaging, broadcast, and so on. These systems may be capable of supporting communication with multiple users by sharing the available system resources, such as time, frequency, and power. Examples of such multiple-access systems include fourth generation (4G) systems such as Long Term Evolution (LTE) systems, LTE-Advanced (LTE-A) systems, or LTE-A Pro systems, and fifth generation (5G) systems which may be referred to as New Radio (NR) systems. These systems may employ technologies such as code division multiple access (CDMA) , time division multiple access (TDMA) , frequency division multiple access (FDMA) , orthogonal frequency division multiple access (OFDMA) , or discrete Fourier transform spread orthogonal frequency division multiplexing (DFT-S-OFDM) . A wireless multiple-access communications system may include one or more base stations or one or more network access nodes, each simultaneously supporting communication for multiple communication devices, which may be otherwise known as user equipment (UE) .

SUMMARY

The systems, methods, and devices of this disclosure each have several innovative aspects, no single one of which is solely responsible for the desirable attributes disclosed herein.

One innovative aspect of the subject matter described in this disclosure can be implemented in a method for wireless communications at a first device. The method may include receiving a sidelink control message from a second device, the sidelink control message including sharing information for a channel occupancy time (COT) of a communication link, determining whether the first device is one of a set of devices with which the second device shares the COT based on the sidelink control message, and communicating over the communication link within the COT based on the determining.

Another innovative aspect of the subject matter described in this disclosure can be implemented in an apparatus for wireless communications. The apparatus may include a first interface, a second interface, and a processing system. The first interface may be configured to obtain a sidelink control message sent from a device, the sidelink control message including sharing information for a COT of a communication link. The processing system may be configured to determine whether the apparatus corresponds to one of a set of devices with which the device shares the COT based on the sidelink control message. The first interface, the second interface, or a combination thereof may be configured to obtain signaling, output signaling, or both based on the determining.

Another innovative aspect of the subject matter described in this disclosure can be implemented in an apparatus for wireless communications at a first device. The apparatus may include a processor, memory coupled with the processor, and instructions stored in the memory. The instructions may be executable by the processor to cause the apparatus to receive a sidelink control message from a second device, the sidelink control message including sharing information for a COT of a communication link, determine whether the first device is one of a set of devices with which the second device shares the COT based on the sidelink control message, and communicate over the communication link within the COT based on the determining.

Another innovative aspect of the subject matter described in this disclosure can be implemented in another apparatus for wireless communications at a first device. The apparatus may include means for receiving a sidelink control message from a second device, the sidelink control message including sharing information for a COT of a communication link, determining whether the first device is one of a set of devices with which the second device shares the COT based on the sidelink control message, and communicating over the communication link within the COT based on the determining.

Another innovative aspect of the subject matter described in this disclosure can be implemented in a non-transitory computer-readable medium storing code for wireless communications at a first device. The code may include instructions executable by a processor to receive a sidelink control message from a second device, the sidelink control message including sharing information for a COT of a communication link, determine whether the first device is one of a set of devices with which the second device shares the COT based on the sidelink control message, and communicate over the communication link within the COT based on the determining.

n some implementations, the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for determining that the sidelink control message supports the second device sharing the COT with the first device based on the sharing information for the COT.

In some implementations, the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for transmitting a sidelink message to a third device of the set of devices different from the second device within the COT based on the sidelink control message supporting the second device sharing the COT with the first device.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the sidelink control message may include a hop counter indicating a number of devices sharing the COT. In some implementations, the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for comparing the hop counter to a threshold number of hops, where the sidelink control message may be determined to support the second device sharing the COT with the first device based on the comparing the hop counter to the threshold number of hops.

In some implementations, the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for updating the hop counter, where the sidelink message transmitted to the third device may include the updated hop counter.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the updating may involve incrementing the hop counter or decrementing the hop counter.

In some implementations, the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for identifying a threshold distance supporting sharing of the COT, determining a distance between a source node for sharing the COT and the first device, the source node for sharing the COT and the third device, or a combination thereof, and comparing the determined distance to the threshold distance, where the sidelink control message may be determined to support the second device sharing the COT with the first device further based on the comparing the determined distance to the threshold distance.

In some implementations, the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for identifying a threshold distance supporting sharing of the COT, determining a distance between a source node for sharing the COT and the first device, the source node for sharing the COT and the third device, or a combination thereof, and comparing the determined distance to the threshold distance, where the sidelink control message may be determined to support the second device sharing the COT with the first device based on the comparing the determined distance to the threshold distance.

In some implementations, the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for receiving a radio resource control (RRC) configuration message indicating the threshold distance supporting sharing of the COT.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the sidelink control message may include a first indication of the source node, and the sidelink message transmitted to the third device may include a second indication of the source node.

In some implementations, the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for determining location information for the source node, the first device, the third device, or a combination thereof based on the threshold distance supporting sharing of the COT.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the second device may correspond to a source node for sharing the COT. In some implementations, the communicating may include operations, features, means, or instructions for receiving a sidelink data message from the second device within the COT based on the sidelink control message and transmitting a feedback message to the second device within the COT in response to the sidelink data message based on the sidelink control message supporting the second device sharing the COT with the first device and the second device corresponding to the source node.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the sidelink control message may include a bit indicating if the sidelink control message supports sharing of the COT.

In some implementations, the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for determining that the sidelink control message serves a fourth device different from the first device.

In some implementations, the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for determining that the sidelink control message restricts the second device from sharing the COT with the first device based on the sharing information for the COT. In some implementations, the communicating may include operations, features, means, or instructions for receiving a sidelink data message from the second device within the COT based on the sidelink control message.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the sidelink control message may include a hop counter indicating a number of devices sharing the COT. In some implementations, the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for comparing the hop counter to a threshold number of hops, where the sidelink control message may be determined to restrict the second device from sharing the COT with the first device based on the hop counter corresponding to the threshold number of hops.

In some implementations, the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for identifying a threshold distance supporting sharing of the COT, determining a distance between a source node for sharing the COT and the first device, and comparing the determined distance to the threshold distance, where the sidelink control message may be determined to restrict the second device from sharing the COT with the first device based on the comparing the determined distance to the threshold distance.

In some implementations, the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for refraining from transmitting a sidelink message within the COT based on the sidelink control message restricting the second device from sharing the COT with the first device.

In some implementations, the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for receiving a sidelink data message from the second device within the COT based on the sidelink control message and refraining from transmitting a feedback message to the second device within the COT in response to the sidelink data message based on the second device corresponding to a node subsequent to a source node for sharing the COT.

In some implementations, the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for determining a group identifier associated with the sidelink control message, where whether the first device is one of the set of devices with which the second device shares the COT may be determined based on the group identifier.

In some implementations, the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for transmitting a sidelink message within the COT based on a group of devices corresponding to the group identifier including the first device.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the sidelink message may include the group identifier.

In some implementations, the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for refraining from transmitting a sidelink message within the COT based on a group of devices corresponding to the group identifier not including the first device.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the sidelink control message may include the group identifier.

In some implementations, the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for determining the group identifier based on a source node for sharing the COT, a device served by the sidelink control message, or a combination thereof.

In some implementations, the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for receiving an RRC configuration message indicating the group identifier for the first device, a set of devices corresponding to the group identifier, or a combination thereof.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the sidelink control message may include a first stage control message received on a physical sidelink control channel (PSCCH) , a second stage control message received on a physical sidelink shared channel (PSSCH) , or a combination thereof.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the first device may be a first user equipment (UE) , a first access point (AP) , a first base station, or a combination thereof, and the second device may be a second UE, a second AP, a second base station, or a combination thereof.

Another innovative aspect of the subject matter described in this disclosure can be implemented in a method for wireless communications at a first device. The method may include gaining access to a communication link for a COT, generating a sidelink control message, the sidelink control message including sharing information for the COT of the communication link, and transmitting the sidelink control message to a second device, where the sidelink control message indicates whether the second device is one of a set of devices with which the first device shares the COT based on the sharing information.

Another innovative aspect of the subject matter described in this disclosure can be implemented in an apparatus for wireless communications. The apparatus may include a first interface, a second interface, and a processing system. The processing system may be configured to gain access to a communication link for a COT and generate a sidelink control message, the sidelink control message including sharing information for the COT of the communication link. The first interface may be configured to output the sidelink control message for transmission to a device, where the sidelink control message indicates whether the device is one of a set of devices with which the apparatus shares the COT based on the sharing information. In some implementations, the second interface may be configured to obtain information, such as a feedback message sent from the device within the COT in response to a sidelink message.

Another innovative aspect of the subject matter described in this disclosure can be implemented in an apparatus for wireless communications at a first device. The apparatus may include a processor, memory coupled with the processor, and instructions stored in the memory. The instructions may be executable by the processor to cause the apparatus to gain access to a communication link for a COT, generate a sidelink control message, the sidelink control message including sharing information for the COT of the communication link, and transmit the sidelink control message to a second device, where the sidelink control message indicates whether the second device is one of a set of devices with which the first device shares the COT based on the sharing information.

Another innovative aspect of the subject matter described in this disclosure can be implemented in another apparatus for wireless communications at a first device. The apparatus may include means for gaining access to a communication link for a COT, generating a sidelink control message, the sidelink control message including sharing information for the COT of the communication link, and transmitting the sidelink control message to a second device, where the sidelink control message indicates whether the second device is one of a set of devices with which the first device shares the COT based on the sharing information.

Another innovative aspect of the subject matter described in this disclosure can be implemented in a non-transitory computer-readable medium storing code for wireless communications at a first device. The code may include instructions executable by a processor to gain access to a communication link for a COT, generate a sidelink control message, the sidelink control message including sharing information for the COT of the communication link, and transmit the sidelink control message to a second device, where the sidelink control message indicates whether the second device is one of a set of devices with which the first device shares the COT based on the sharing information.

In some implementations, the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for transmitting a sidelink data message to the second device within the COT based on the sidelink control message and receiving a feedback message from the second device within the COT in response to the sidelink data message based on the sidelink control message supporting the first device sharing the COT with the second device and the first device corresponding to a source node for sharing the COT.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the sidelink control message may include a hop counter indicating a number of devices sharing the COT, a bit indicating if the sidelink control message supports sharing of the COT, or a combination thereof, and whether the second device is one of the set of devices with which the first device shares the COT may be based on the hop counter, the bit, or a combination thereof.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the sidelink control message may include an indication of the first device as a source node for sharing the COT, and whether the second device is one of the set of devices with which the first device shares the COT may be based on a distance from the source node.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the sidelink control message may include a group identifier, and whether the second device is one of the set of devices with which the first device shares the COT may be based on the group identifier.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the first device may be a first UE, a first AP, a first base station, or a combination thereof, and the second device may be a second UE, a second AP, a second base station, or a combination thereof.

Details of one or more implementations of the subject matter described in this disclosure are set forth in the accompanying drawings and the description below. Other features, aspects, and advantages will become apparent from the description, the drawings and the claims. Note that the relative dimensions of the following figures may not be drawn to scale.

BRIEF DESCRIPTION OF THE DRAWINGS

Figures 1–4 illustrate examples of wireless communications systems that support hop-based channel occupancy time (COT) sharing.

Figures 5 and 6 illustrate examples of process flows that support hop-based COT sharing.

Figure 7 shows a block diagram of an example device that supports hop-based COT sharing.

Figures 8–12 show flowcharts illustrating example methods that support hop-based COT sharing.

Like reference numbers and designations in the various drawings indicate like elements.

DETAILED DESCRIPTION

The following description is directed to certain implementations for the purposes of describing the innovative aspects of this disclosure. However, a person having ordinary skill in the art will readily recognize that the teachings herein can be applied in a multitude of different ways. The described implementations may be implemented in any device, system or network that is capable of transmitting and receiving radio frequency (RF) signals according to any of the Institute of Electrical and Electronics Engineers (IEEE) 16.11 standards, or any of the IEEE 802.11 standards, the

standard, code division multiple access (CDMA) , frequency division multiple access (FDMA) , time division multiple access (TDMA) , Global System for Mobile communications (GSM) , GSM/General Packet Radio Service (GPRS) , Enhanced Data GSM Environment (EDGE) , Terrestrial Trunked Radio (TETRA) , Wideband-CDMA (W-CDMA) , Evolution Data Optimized (EV-DO) , 1xEV-DO, EV-DO Rev A, EV-DO Rev B, High Speed Packet Access (HSPA) , High Speed Downlink Packet Access (HSDPA) , High Speed Uplink Packet Access (HSUPA) , Evolved High Speed Packet Access (HSPA+) , Long Term Evolution (LTE) , AMPS, or other known signals that are used to communicate within a wireless, cellular or internet of things (IOT) network, such as a system utilizing 3G, 4G or 5G, or further implementations thereof, technology.

In some wireless communications systems, a device may communicate with additional devices via sidelink communications. For example, a user equipment (UE) may gain access to a sidelink channel for a specific channel occupancy time (COT) and may transmit one or more sidelink messages over the sidelink channel during the COT. To support efficient sidelink channel access and usage, a wireless communications system may implement sidelink COT sharing. Sidelink COT sharing may involve a first UE gaining access to the sidelink channel for a COT and transmitting a sidelink message, such as a sidelink control message, in the COT to a second UE. The sidelink control message, such as a first stage sidelink control information (SCI-1) message or a second stage sidelink control information (SCI-2) message, may include sharing information for the COT. Based on the sharing information, the second UE may determine whether the COT supports sharing by the second UE. For example, if the second UE determines that sharing is supported for the COT, the second UE may transmit a sidelink message on the sidelink channel within the same COT as the first UE. In some examples, the second UE may transmit a sidelink control message, a sidelink data message, or both to a third UE. Further, the second UE may transmit a sidelink feedback message to the first UE, or may transmit some combination thereof within the shared COT.

In some implementations, a wireless communications system may support multiple hops for sidelink COT sharing. For example, a first UE may share a COT with a second UE (for example, in a first “hop” ) , and the second UE may further share the same COT with a third UE (in a second hop) . Using multi-hop COT sharing, multiple additional UEs may transmit sidelink messages in a single COT. Additionally, or alternatively, a UE may share a COT with non-served UEs. For example, a first UE may transmit a sidelink message to a second UE in a COT. A third UE detecting and decoding the sidelink message, such as a sidelink control message including sharing information, may determine that the COT supports sharing by the third UE according to the sidelink message serving the second UE.

As described herein, sidelink COT sharing may be based on one or more parameters. For example, sidelink COT sharing may be based on a sharing indicator, a hop counter, a distance threshold, a group indicator, or any combination thereof. A UE receiving a sidelink control message in a COT may determine whether sidelink COT sharing is supported for the UE based on the sidelink control message. In some implementations, the sidelink control message may include a COT sharing indicator (for example, a bit flag indicating either support for sharing or no support for sharing) . In some other implementations, the sidelink control message may include a hop counter, indicating how many hops away an additional UE may share the COT. If a UE receives a sidelink control message with a hop counter of zero, the UE may determine that further sharing of the COT is restricted. Additionally, or alternatively, the sidelink control message may include an indication of a source UE initiating the COT sharing. UEs located within a specific distance threshold from the source UE may share the COT. Additionally, or alternatively, the UEs in the wireless communications system may be grouped into specific UE groups. A UE assigned a specific group index may determine whether COT sharing is supported based on a group index associated with a sidelink control message. For example, the group index associated with the sidelink control message may be explicitly indicated in the sidelink control message or implicitly indicated by a group index for the source UE, the target UE, or both for the sidelink control message. In some examples, UEs in a specific group may share a sidelink COT with other UEs in the same group.

Particular implementations of the subject matter described in this disclosure can be implemented to realize one or more of the following potential advantages. For example, sharing a COT with other devices for sidelink communication may improve sidelink channel access. A first UE may perform a procedure to gain access to a sidelink channel for a COT and, by using sidelink COT sharing, multiple additional UEs may transmit sidelink messages during the COT without performing the same access procedures. In some examples, the additional UEs may perform shortened access procedures-in comparison to the initial channel access procedure-to share the COT, significantly reducing latency for sidelink communications in the system. Additionally, or alternatively, COT sharing may improve resource allocation for the sidelink channel. For example, a UE may share the time resources within the COT for transmissions to or from other devices. By sharing the COT, a greater number of transmissions may occur during the COT, which may increase efficiency and reduce latency in the system. Additionally, by using a sharing indicator, a hop counter, a distance threshold, a group identifier, or any combination thereof in a sidelink control message, a UE may control the level of sidelink COT sharing supported for a specific COT. Such a level of control over sidelink COT sharing may further increase efficiencies in the system and allow for dynamic COT sharing procedures. Additionally, or alternatively, controlling the level of sidelink COT sharing can improve the fairness of the channel access with other devices using the channel, such as WiFi nodes or New Radio-Unlicensed (NR-U) nodes.

Figure 1 illustrates an example of a wireless communications system 100 that supports hop-based COT sharing. The wireless communications system 100 may include one or more base stations 105, one or more UEs 115, and a core network 130. In some examples, the wireless communications system 100 may be a Long Term Evolution (LTE) network, an LTE-Advanced (LTE-A) network, an LTE-A Pro network, or a New Radio (NR) network. In some examples, the wireless communications system 100 may support enhanced broadband communications, ultra-reliable, such as mission critical, communications, low latency communications, communications with low-cost and low-complexity devices, or any combination thereof.

The base stations 105 may be dispersed throughout a geographic area to form the wireless communications system 100 and may be devices in different forms or having different capabilities. The base stations 105 and the UEs 115 may wirelessly communicate via one or more communication links 125. Each base station 105 may provide a coverage area 110 over which the UEs 115 and the base station 105 may establish one or more communication links 125. The coverage area 110 may be an example of a geographic area over which a base station 105 and a UE 115 may support the communication of signals according to one or more radio access technologies.

The UEs 115 may be dispersed throughout a coverage area 110 of the wireless communications system 100, and each UE 115 may be stationary, or mobile, or both at different times. The UEs 115 may be devices in different forms or having different capabilities. Some example UEs 115 are illustrated in Figure 1. The UEs 115 described herein may be able to communicate with various types of devices, such as other UEs 115, the base stations 105, or network equipment, such as core network nodes, relay devices, integrated access and backhaul (IAB) nodes, or other network equipment, as shown in Figure 1.

The base stations 105 may communicate with the core network 130, or with one another, or both. For example, the base stations 105 may interface with the core network 130 through one or more backhaul links 120, such as via an S1, N2, N3, or another interface. The base stations 105 may communicate with one another over the backhaul links 120, such as via an X2, Xn, or other interface, either directly, which may be directly between base stations 105, or indirectly, which may be via core network 130, or both. In some examples, the backhaul links 120 may be or include one or more wireless links.

One or more of the base stations 105 described herein may include or may be referred to by a person having ordinary skill in the art as a base transceiver station, a radio base station, an access point, a radio transceiver, a NodeB, an eNodeB (eNB) , a next-generation NodeB or a giga-NodeB (either of which may be referred to as a gNB) , a Home NodeB, a Home eNodeB, or other suitable terminology.

A UE 115 may include or may be referred to as a mobile device, a wireless device, a remote device, a handheld device, or a subscriber device, or some other suitable terminology, where the “device” also may be referred to as a unit, a station, a terminal, or a client, among other examples. A UE 115 also may include or may be referred to as a personal electronic device such as a cellular phone, a personal digital assistant (PDA) , a tablet computer, a laptop computer, or a personal computer. In some examples, a UE 115 may include or be referred to as a wireless local loop (WLL) station, an Internet of Things (IoT) device, an Internet of Everything (IoE) device, or a machine type communications (MTC) device, among other examples, which may be implemented in various objects such as appliances, or vehicles, meters, among other examples.

The UEs 115 described herein may be able to communicate with various types of devices, such as other UEs 115 that may sometimes act as relays as well as the base stations 105 and the network equipment including macro eNBs or gNBs, small cell eNBs or gNBs, or relay base stations, among other examples, as shown in Figure 1.

The UEs 115 and the base stations 105 may wirelessly communicate with one another via one or more communication links 125 over one or more carriers. The term “carrier” may refer to a set of radio frequency spectrum resources having a defined physical layer structure for supporting the communication links 125. For example, a carrier used for a communication link 125 may include a portion of a radio frequency spectrum band, such as a bandwidth part (BWP) , that is operated according to one or more physical layer channels for a given radio access technology, such as LTE, LTE-A, LTE-A Pro, NR. Each physical layer channel may carry acquisition signaling, such as synchronization signals or system information, control signaling that coordinates operation for the carrier, user data, or other signaling. The wireless communications system 100 may support communication with a UE 115 using carrier aggregation or multi-carrier operation. A UE 115 may be configured with multiple downlink component carriers and one or more uplink component carriers according to a carrier aggregation configuration. Carrier aggregation may be used with both frequency division duplexing (FDD) and time division duplexing (TDD) component carriers.

Signal waveforms transmitted over a carrier may be made up of multiple subcarriers (for example, using multi-carrier modulation (MCM) techniques such as orthogonal frequency division multiplexing (OFDM) or discrete Fourier transform spread OFDM (DFT-S-OFDM) ) . In a system employing MCM techniques, a resource element may consist of one symbol period (a duration of one modulation symbol) and one subcarrier, where the symbol period and subcarrier spacing are inversely related. The number of bits carried by each resource element may depend on the modulation scheme (for example, the order of the modulation scheme, the coding rate of the modulation scheme, or both) . Thus, the more resource elements that a UE 115 receives and the higher the order of the modulation scheme, the higher the data rate may be for the UE 115. A wireless communications resource may refer to a combination of a radio frequency spectrum resource, a time resource, and a spatial resource (for example, spatial layers or beams) , and the use of multiple spatial layers may further increase the data rate or data integrity for communications with a UE 115.

The time intervals for the base stations 105 or the UEs 115 may be expressed in multiples of a basic time unit which may, for example, refer to a sampling period of T _s= 1/ (Δf _max·N _f) seconds, where Δf _max may represent the maximum supported subcarrier spacing, and N _f may represent the maximum supported discrete Fourier transform (DFT) size. Time intervals of a communications resource may be organized according to radio frames each having a specified duration (for example, 10 milliseconds (ms) ) . Each radio frame may be identified by a system frame number (SFN) (for example, ranging from 0 to 1023) .

Each frame may include multiple consecutively numbered subframes or slots, and each subframe or slot may have the same duration. In some examples, a frame may be divided (for example, in the time domain) into subframes, and each subframe may be further divided into a number of slots. Alternatively, each frame may include a variable number of slots, and the number of slots may depend on subcarrier spacing. Each slot may include a number of symbol periods (depending on the length of the cyclic prefix prepended to each symbol period) . In some wireless communications systems 100, a slot may further be divided into multiple mini-slots containing one or more symbols. Excluding the cyclic prefix, each symbol period may contain one or more (N _f) sampling periods. The duration of a symbol period may depend on the subcarrier spacing or frequency band of operation.

A subframe, a slot, a mini-slot, or a symbol may be the smallest scheduling unit (for example, in the time domain) of the wireless communications system 100 and may be referred to as a transmission time interval (TTI) . In some examples, the TTI duration (for example, the number of symbol periods in a TTI) may be variable. Additionally, or alternatively, the smallest scheduling unit of the wireless communications system 100 may be dynamically selected, for example, in bursts of shortened TTIs (sTTIs) .

Physical channels may be multiplexed on a carrier according to various techniques. A physical control channel and a physical data channel may be multiplexed on a downlink carrier, for example, using one or more of time division multiplexing (TDM) techniques, frequency division multiplexing (FDM) techniques, or hybrid TDM-FDM techniques. A control region (for example, a control resource set (CORESET) ) for a physical control channel may be defined by a number of symbol periods and may extend across the system bandwidth or a subset of the system bandwidth of the carrier. One or more control regions may be configured for a set of the UEs 115. For example, one or more of the UEs 115 may monitor or search control regions for control information according to one or more search space sets, and each search space set may include one or multiple control channel candidates in one or more aggregation levels arranged in a cascaded manner. An aggregation level for a control channel candidate may refer to a number of control channel resources (for example, control channel elements (CCEs) ) associated with encoded information for a control information format having a given payload size. Search space sets may include common search space sets configured for sending control information to multiple UEs 115 and UE-specific search space sets for sending control information to a specific UE 115.

In some examples, a base station 105 may be movable and therefore provide communication coverage for a moving geographic coverage area 110. In some examples, different geographic coverage areas 110 associated with different technologies may overlap, but the different geographic coverage areas 110 may be supported by the same base station 105. In some other examples, the overlapping geographic coverage areas 110 associated with different technologies may be supported by different base stations 105. The wireless communications system 100 may include, for example, a heterogeneous network in which different types of the base stations 105 provide coverage for various geographic coverage areas 110 using the same or different radio access technologies.

The wireless communications system 100 may support synchronous or asynchronous operation. For synchronous operation, the base stations 105 may have similar frame timings, and transmissions from different base stations 105 may be approximately aligned in time. For asynchronous operation, the base stations 105 may have different frame timings, and transmissions from different base stations 105 may, in some examples, not be aligned in time. The techniques described herein may be used for either synchronous or asynchronous operations.

Some UEs 115 may be configured to employ operating modes that reduce power consumption, such as half-duplex communications (for example, a mode that supports one-way communication via transmission or reception, but not transmission and reception simultaneously) . In some examples, half-duplex communications may be performed at a reduced peak rate. Other power conservation techniques for the UEs 115 include entering a power saving deep sleep mode when not engaging in active communications, operating over a limited bandwidth (for example, according to narrowband communications) , or a combination of these techniques. For example, some UEs 115 may be configured for operation using a narrowband protocol type that is associated with a defined portion or range (for example, set of subcarriers or resource blocks (RBs) ) within a carrier, within a guard-band of a carrier, or outside of a carrier.

The wireless communications system 100 may be configured to support ultra-reliable communications or low-latency communications, or various combinations thereof. For example, the wireless communications system 100 may be configured to support ultra-reliable low-latency communications (URLLC) or mission critical communications. The UEs 115 may be designed to support ultra-reliable, low-latency, or critical functions (for example, mission critical functions) . Ultra-reliable communications may include private communication or group communication and may be supported by one or more mission critical services such as mission critical push-to-talk (MCPTT) , mission critical video (MCVideo) , or mission critical data (MCData) . Support for mission critical functions may include prioritization of services, and mission critical services may be used for public safety or general commercial applications. The terms ultra-reliable, low-latency, mission critical, and ultra-reliable low-latency may be used interchangeably herein.

In some examples, a UE 115 also may be able to communicate directly with other UEs 115 over a device-to-device (D2D) communication link 135 (for example, using a peer-to-peer (P2P) or D2D protocol) . One or more UEs 115 utilizing D2D communications may be within the geographic coverage area 110 of a base station 105. Other UEs 115 in such a group may be outside the geographic coverage area 110 of a base station 105 or be otherwise unable to receive transmissions from a base station 105. In some examples, groups of the UEs 115 communicating via D2D communications may utilize a one-to-many (1: M) system in which each UE 115 transmits to every other UE 115 in the group. In some examples, a base station 105 facilitates the scheduling of resources for D2D communications. In some other examples, D2D communications are carried out between the UEs 115 without the involvement of a base station 105.

In some systems, the D2D communication link 135 may be an example of a communication channel, such as a sidelink communication channel, between vehicles (for example, UEs 115) . In some examples, vehicles may communicate using vehicle-to-everything (V2X) communications, vehicle-to-vehicle (V2V) communications, or some combination of these. A vehicle may signal information related to traffic conditions, signal scheduling, weather, safety, emergencies, or any other information relevant to a V2X system. In some examples, vehicles in a V2X system may communicate with roadside infrastructure, such as roadside units, or with the network via one or more network nodes (for example, base stations 105) using vehicle-to-network (V2N) communications, or with both.

The core network 130 may provide user authentication, access authorization, tracking, Internet Protocol (IP) connectivity, and other access, routing, or mobility functions. The core network 130 may be an evolved packet core (EPC) or 5G core (5GC) , which may include at least one control plane entity that manages access and mobility (for example, a mobility management entity (MME) , an access and mobility management function (AMF) ) and at least one user plane entity that routes packets or interconnects to external networks (for example, a serving gateway (S-GW) , a Packet Data Network (PDN) gateway (P-GW) , or a user plane function (UPF) ) . The control plane entity may manage non-access stratum (NAS) functions such as mobility, authentication, and bearer management for the UEs 115 served by the base stations 105 associated with the core network 130. User IP packets may be transferred through the user plane entity, which may provide IP address allocation as well as other functions. The user plane entity may be connected to the network operators IP services 150. The operators IP services 150 may include access to the Internet, Intranet (s) , an IP Multimedia Subsystem (IMS) , or a Packet-Switched Streaming Service.

Some of the network devices, such as a base station 105, may include subcomponents such as an access network entity 140, which may be an example of an access node controller (ANC) . Each access network entity 140 may communicate with the UEs 115 through one or more other access network transmission entities 145, which may be referred to as radio heads, smart radio heads, or transmission/reception points (TRPs) . Each access network transmission entity 145 may include one or more antenna panels. In some configurations, various functions of each access network entity 140 or base station 105 may be distributed across various network devices (for example, radio heads and ANCs) or consolidated into a single network device, such as a base station 105.

The wireless communications system 100 may operate using one or more frequency bands, typically in the range of 300 megahertz (MHz) to 300 gigahertz (GHz) . Generally, the region from 300 MHz to 3 GHz is known as the ultra-high frequency (UHF) region or decimeter band because the wavelengths range from approximately one decimeter to one meter in length. The UHF waves may be blocked or redirected by buildings and environmental features, but the waves may penetrate structures sufficiently for a macro cell to provide service to the UEs 115 located indoors. The transmission of UHF waves may be associated with smaller antennas and shorter ranges (for example, less than 100 kilometers) compared to transmission using the smaller frequencies and longer waves of the high frequency (HF) or very high frequency (VHF) portion of the spectrum below 300 MHz.

The wireless communications system 100 may utilize both licensed and unlicensed radio frequency spectrum bands. For example, the wireless communications system 100 may employ License Assisted Access (LAA) , LTE-Unlicensed (LTE-U) radio access technology, or NR technology in an unlicensed band such as the 5 GHz industrial, scientific, and medical (ISM) band. When operating in unlicensed radio frequency spectrum bands, devices such as the base stations 105 and the UEs 115 may employ carrier sensing for collision detection and avoidance. In some examples, operations in unlicensed bands may be based on a carrier aggregation configuration in conjunction with component carriers operating in a licensed band (for example, LAA) . Operations in unlicensed spectrum may include downlink transmissions, uplink transmissions, P2P transmissions, or D2D transmissions, among other examples.

A base station 105 or a UE 115 may be equipped with multiple antennas, which may be used to employ techniques such as transmit diversity, receive diversity, multiple-input multiple-output (MIMO) communications, or beamforming. The antennas of a base station 105 or a UE 115 may be located within one or more antenna arrays or antenna panels, which may support MIMO operations or transmit or receive beamforming. For example, one or more base station antennas or antenna arrays may be co-located at an antenna assembly, such as an antenna tower. In some examples, antennas or antenna arrays associated with a base station 105 may be located in diverse geographic locations. A base station 105 may have an antenna array with a number of rows and columns of antenna ports that the base station 105 may use to support beamforming of communications with a UE 115. Likewise, a UE 115 may have one or more antenna arrays that may support various MIMO or beamforming operations. Additionally, or alternatively, an antenna panel may support radio frequency beamforming for a signal transmitted via an antenna port.

Beamforming, which also may be referred to as spatial filtering, directional transmission, or directional reception, is a signal processing technique that may be used at a transmitting device or a receiving device (for example, a base station 105 or a UE 115) to shape or steer an antenna beam (for example, a transmit beam or a receive beam) along a spatial path between the transmitting device and the receiving device. Beamforming may be achieved by combining the signals communicated via antenna elements of an antenna array such that some signals propagating at particular orientations with respect to an antenna array experience constructive interference while others experience destructive interference. The adjustment of signals communicated via the antenna elements may include a transmitting device or a receiving device applying amplitude offsets, phase offsets, or both to signals carried via the antenna elements associated with the device. The adjustments associated with each of the antenna elements may be defined by a beamforming weight set associated with a particular orientation (for example, with respect to the antenna array of the transmitting device or receiving device, or with respect to some other orientation) .

The wireless communications system 100 may be a packet-based network that operates according to a layered protocol stack. In the user plane, communications at the bearer or Packet Data Convergence Protocol (PDCP) layer may be IP-based. A Radio Link Control (RLC) layer may perform packet segmentation and reassembly to communicate over logical channels. A Medium Access Control (MAC) layer may perform priority handling and multiplexing of logical channels into transport channels. The MAC layer also may use error detection techniques, error correction techniques, or both to support retransmissions at the MAC layer to improve link efficiency. In the control plane, the Radio Resource Control (RRC) protocol layer may provide establishment, configuration, and maintenance of an RRC connection between a UE 115 and a base station 105 or a core network 130 supporting radio bearers for user plane data. At the physical layer, transport channels may be mapped to physical channels.

The UEs 115 and the base stations 105 may support retransmissions of data to increase the likelihood that data is received successfully. Hybrid automatic repeat request (HARQ) feedback is one technique for increasing the likelihood that data is received correctly over a communication link 125. HARQ may include a combination of error detection (for example, using a cyclic redundancy check (CRC) ) , forward error correction (FEC) , and retransmission (for example, automatic repeat request (ARQ) ) . HARQ may improve throughput at the MAC layer in poor radio conditions, such as low signal-to-noise conditions. In some examples, a device may support same-slot HARQ feedback, where the device may provide HARQ feedback in a specific slot for data received in a previous symbol in the slot. In some other examples, the device may provide HARQ feedback in a subsequent slot, or according to some other time interval.

Some wireless communications systems 100 may support COT sharing between a base station 105 and a UE 115. For example, in some implementations, such as in a system implementing NR-U operations, a base station 105 may share a COT with one or more UEs 115 in a process referred to as downlink-to-uplink COT sharing. For downlink-to-uplink COT sharing, the base station 105 may acquire a COT using an extended clear channel assessment (eCCA) and may share the COT with one or more UEs 115. The one or more UEs 115 may transmit one or more uplink signals during the COT. In some examples, within the COT shared by the base station, the one or more UEs 115 may access the channel for uplink transmissions using a procedure involving a reduced time frame (for example, as compared to the eCCA performed by the base station) . Such a procedure may involve a UE 115 performing a CCA, such as a single shot CCA, performing a listen-before-talk (LBT) procedure, or refraining from performing an LBT procedure for the channel. For example, the one or more UEs 115 may use a Category 2 LBT procedure to monitor the channel for downlink-to-uplink gaps approximately between 16 microseconds (μs) and 25 μs or a Category 1 LBT procedure to monitor the channel for downlink-to-uplink gaps equal to or less than approximately 16 μs.

An LBT procedure may include different Categories for attempting to access an unlicensed frequency band. For example, a Category 1 LBT may enable a UE 115 (or a different device) to transmit a message on the unlicensed frequency band after a switching gap of approximately 16 μs. A Category 2 LBT may include an LBT without a random back-off (RBO) , in which a CCA period (that is, a time duration where a device listens to the unlicensed frequency band to determine if signaling is present or not) is deterministic (for example, a duration of time that the channel is sensed to be idle or not before a transmitting entity transmits may be deterministic, such as fixed to 25 μs) . A Category 3 LBT may include an LBT with a random back-off with a contention window of a fixed size, in which an extended CCA period is drawn by a random number within a fixed contention window (that is, a random number is used in the LBT procedure to determine the duration of time that the channel is sensed to be idle or not before the transmitting entity transmits on the channel) . A Category 4 LBT may include an LBT with a random back-off with a contention window of a variable size, in which an extended CCA period is drawn by a random number within a contention window, whose size can vary based on channel dynamics (that is, the transmitting entity can vary the size of the contention window when drawing a random number, and the random number is used in the LBT procedure to determine the duration of time that the channel is sensed to be idle before the transmitting entity transmits on the channel) . The different Categories may be used for different scenarios. For example, the Category 4 LBT may be used by a base station 105 or a UE 115 to initiate a COT for data transmissions, while a base station 105 may use the Category 2 LBT for signaling such as discovery reference signals.

Additionally, or alternatively, a UE 115 may share a COT with a base station 105 in a process referred to as uplink-to-downlink COT sharing. In some implementations, a UE 115 may initiate a channel occupancy, for example, by gaining access to the channel for a COT using a configured grant-physical uplink shared channel (CG-PUSCH) or uplink scheduling. The UE 115 may share the COT with a base station 105, such that the base station 105 may transmit control signals, broadcast signals, or a combination thereof for any UEs 115 during the COT. In some implementations, the base station 105 may transmit the control signals, broadcast signals, or both if the signals include information for the UE 115 that initiated the channel occupancy. Additionally, or alternatively, the base station 105 may transmit downlink signals (for example, on a physical downlink shared channel (PDSCH) , a physical downlink control channel (PDCCH) , or both) , such as downlink data signals, downlink reference signals, or a combination thereof for the UE 115 that initiated the channel occupancy.

In some implementations, the base station 105 may configure an energy detection (ED) threshold for the UE 115 to apply when initiating a channel occupancy to be shared with the base station (for example, via radio resource control (RRC) signaling) . If the base station 105 does not configure the UE 115 with an ED threshold, the base station 105 transmission in the COT initiated by the UE 115 may include control signals, broadcast signals, or channel transmissions of a preconfigured number of OFDM symbols, which may be up to 2, 4, or 8 OFDM symbols, in the COT duration, which may be for a 15, 30, or 60 kHz subcarrier spacing (SCS) . In some examples, such as when WiFi communications may be present (like when based on a communication regulation) , the base station 105 may determine with which ED threshold to configure a UE 115 based on a base station transmission power. As with downlink-to-uplink COT sharing, a Category 2 LBT procedure may be implemented for uplink-to-downlink gaps of approximately between 16 μs and 25 μs, while a Category 1 LBT procedure may be used for uplink-to-downlink gaps equal to or less than approximately 16 μs. In some implementations, COT sharing, such as downlink-to- uplink or uplink-to-downlink COT sharing, may improve medium access within the COT for each node, such as a base station 105, one or more UEs 115, or some combination thereof.

In some examples, a wireless communications system 100 may support configured grant (CG) uplink-to-downlink COT sharing. For example, a base station 105 may configure a UE 115 with an ED threshold for uplink-to-downlink COT sharing, which may support the base station 105 sending data to the UE 115 sharing the COT. The base station 105 may configure a table including sharing parameters. In some examples, each row of the table may include a number of slots in which downlink transmissions may be assumed within a COT initiated by the UE 115, the downlink offset indicating the starting slot of the downlink transmission, which may be indicated in number of slots from the end of a slot in which a downlink transmission may be assumed, and a channel access priority class (CAPC) of the traffic. In some implementations, a row of the table may include no COT sharing information. Additionally, or alternatively, the table-for example, a row of the table-may include an uplink control information (UCI) indication for COT sharing.

In some other examples, the base station 105 may not configure a UE 115 with an ED threshold for uplink-to-downlink COT sharing, which may prevent the base station 105 from sending data to the UE 115 sharing the COT. In some such examples, the CG-UCI may carry a COT sharing indication, such as a 1-bit COT sharing indicator. In some implementations, the COT sharing indication may indicate whether a slot or symbol, such as a symbol n+X, may be applicable for uplink-to-downlink COT sharing. The value of X may be configured by the base station via RRC signaling, where X may be the number of symbols from the end of the slot in which the CG-UCI is transmitted.

Some wireless communications systems 100 may support sidelink communications between UEs 115. In some systems, such as systems supporting V2X sidelink communications or other sidelink or D2D communications, there may be a number of modes corresponding to resource allocation. For example, a base station 105 may allocate resources for sidelink communications between UEs 115. The base station 105 may provide a dynamic grant or may activate a configured sidelink grant for sidelink communications between the UEs 115. The UEs 115 may report sidelink feedback to the base station 105. Additionally, or alternatively, the UEs 115 may autonomously select sidelink resources. For example, UEs 115 may schedule sidelink communications, which may be via the PC5 interface, using sidelink control information (SCI) . In some implementations, the SCI may correspond to one or more stages. A UE 115 may transmit an SCI-1 message on a physical sidelink control channel (PSCCH) . The SCI-1 message may include information for resource allocation and decoding of the SCI-2. For example, SCI-1 may include a priority indication, a physical sidelink shared channel (PSSCH) resource assignment, a resource reservation period, a PSSCH demodulation reference signal (DMRS) indication, SCI-2 information (such as the size of SCI-2) , an amount of resources for SCI-2, a number of PSSCH DMRS ports, a modulation coding scheme (MCS) , or the like. The UE 115 may transmit the SCI-2 message on the PSSCH (for example, piggybacked with data on a sidelink data channel) . The SCI-2 message may include information for decoding a PSSCH message. For example, SCI-2 may include a 16-bit layer 1 (L1) destination identifier, an 8-bit L1 source identifier, a HARQ process identifier, a new data indicator (NDI) , a redundancy version, or the like. In some implementations, signaling on the sidelink may be similar for each mode (for example, for a receiver receiving sidelink messages, there may not be a difference between the modes) .

As described herein, in some implementations, such as for NR-U, a base station 105 may share a COT with a UE 115 and a UE 115 may share a COT with a base station 105. For example, a base station 105 may send PDCCH control information or broadcast data to one or more UEs 115 in a shared COT, both of which may not trigger feedback messages-such as an acknowledgement (ACK) or negative acknowledgement (NACK) message-in response. Additionally, or alternatively, in some implementations, a wireless communications system 100 supporting sidelink communications may support sidelink COT sharing. For example, one or more UEs 115 in an NR-U system may support channel access techniques to gain access to a sidelink COT and sidelink COT sharing techniques to improve sidelink access.

In some sidelink COT sharing implementations, a first UE 115 may gain access to the sidelink channel and may send a sidelink transmission to a second UE 115 in a COT. The sidelink transmission may share the COT with the second UE 115 for a feedback transmission, such as an ACK or NACK, to the first UE 115 in response to the sidelink transmission (for example, on a physical sidelink feedback channel (PSFCH) ) . Additionally, or alternatively, in some other sidelink COT sharing implementations, a first UE 115 may send a sidelink transmission to a second UE 115 in a COT, and the sidelink transmission may share the COT with the second UE 115 for an additional sidelink transmission (for example, a sidelink control message, a sidelink data message, or both) within the COT to the first UE 115. Thus, the first and second UEs 115 may transmit sidelink communications sharing a COT. However, strictly sharing the COT between the two UE 115 involved in the sidelink communications, and not with other UEs 115 in the wireless communications system 100, may result in system inefficiencies, such as inefficient sidelink access for UEs 115.

As described herein, the wireless communications system 100 may support the use of techniques that enable a UE 115 to share a COT with one or more other UEs 115 for sidelink communication. In some implementations, a UE 115 in the wireless communications system 100 may receive a sidelink control message from a different UE 115. The sidelink control message may include sharing information for a COT of a communication link, such as a D2D communication link 135. For example, the sidelink control message may include sharing information related to a number of hops, a threshold distance from a source UE 115, a group identifier, or a combination. The UE 115 may determine whether to share the COT with another UE 115 based on the sharing information, where sharing the COT involves transmitting a sidelink message within the COT. For example, the UE 115 may receive a hop counter in the sidelink control message and compare the hop counter to a threshold number of hops. If the hop counter satisfies the threshold number of hops (for example, if the hop counter is greater than zero) , the UE 115 may share the COT and may transmit a sidelink message to one or more additional UEs 115. Additionally, or alternatively, the UE 115 may determine whether to share the COT based on a threshold distance from a source node, such as a UE 115 initially gaining access to the sidelink channel for the COT, or based on a group identifier of the UEs 115. In some implementations, sharing a COT with other UEs 115 for sidelink communications may improve sidelink channel usage and resource allocation in the wireless communications system 100.

Figure 2 illustrates an example of a wireless communications system 200 that supports hop-based COT sharing. In some examples, wireless communications system 200 may implement aspects of a wireless communications system 100 and may include a UE 115-a, a UE 115-b, a UE 115-c, a UE 115-d, a UE 115-e, a UE 115-f, or any combination of these UEs 115. The UEs 115 may be examples of UEs 115 described with reference to Figure 1. For example, the UEs 115 may be capable of sidelink communication during a shared COT, which may increase efficiency in the wireless communications system 200 by improving resource allocation and sidelink channel access within the shared COT.

As described herein, the wireless communications system 200 may support the use of techniques that enable a UE 115 to share a COT with one or more other UEs 115 for sidelink communication. For example, a UE 115-a may gain channel access for sidelink communications for a specific COT. During the COT, the UE 115-a may transmit a sidelink message (for example, a sidelink control message, a sidelink data message, or both) to another UE 115, such as a UE 115-b. As such, the UE 115-a may be serving sidelink information to the UE 115-b. In some examples, the UE 115-a may share the COT with the UE 115-b, for example, for an additional sidelink transmission. The UE 115-b may transmit a sidelink message (for example, a sidelink control message, a sidelink data message, or both) to another UE 115, such as a UE 115-c, in the same COT as the sidelink message from the UE 115-a to the UE 115-b. Each successive sharing of the COT may be referred to as a “hop” 205. For example, a hop 205-a (corresponding to the sidelink message from the UE 115-a to the UE 115-b) may be the first hop for COT sharing, and a hop 205-b (corresponding to the sidelink message from the UE 115-b to the UE 115-c) may be the second hop for COT sharing. In some implementations, the first hop 205-a may support sharing the COT for feedback transmissions. For example, the UE 115-b may transmit an ACK or NACK message to the UE 115-a in the shared COT. However, further hops, such as the second hop 205-b, may not support feedback transmissions. Accordingly, the UE 115-c may not transmit an ACK or NACK message to the UE 115-b in the shared COT in response to the sidelink message transmitted for the hop 205-b. In some examples, a condition for sharing the COT for a sidelink transmission may involve a UE 115 refraining from requesting ACK/NACK feedback for the sidelink transmission.

As described herein, the UE 115-amay share the COT with the UE 115-b by serving the UE 115-b. Additionally, or alternatively, the UE 115-a may share the COT with a UE 115-e in a hop 205-d, even though the UE 115-e may not be served by the UE 115-a. For example, the UE 115-e may detect the sidelink transmission from the UE 115-a to the UE 115-b and may determine that the sidelink transmission supports COT sharing. As such, the UE 115-e may transmit a sidelink message to a UE 115-f in a hop 205-e within the COT. In some implementations, the sidelink transmission from the UE 115-e to the UE 115-f in the hop 205-e may not request a feedback message. In some examples, the number of hops 205 may be calculated according to a direct chain of nodes. For example, hops 205-a and 205-d may both correspond to a first hop, and hops 205-b and 205-e may each correspond to a second hop. In some other examples, the number of hops 205 may be calculated according to a total number of nodes sharing the COT. For example, the hop 205-a may be a first hop, the hop 205-b may be a second hop, and the hop 205-d may be a third hop.

In some examples, COT sharing information may be carried in SCI, such as an SCI-1 message, an SCI-2 message, or a combination thereof. For example, a 1-bit indicator in SCI may indicate whether a COT may be shared further. The 1-bit indicator may correspond to a specific hop 205. For example, a “1” bit value for the sharing indicator may correspond to a first hop 205 and may support further sharing of the COT, while a “0” bit value for the sharing indicator may correspond to a second hop 205 and may not support further sharing of the COT. A UE 115 may receive a sidelink control message including SCI related to a hop 205 and may determine whether the COT is shared with the UE 115 based on the sidelink control message. In some examples, the UE 115 may receive a sidelink control message on a sidelink control channel or a sidelink data channel in a COT, may identify the sharing indicator in the sidelink control message, and may determine how to communicate in the COT based on the sharing indicator.

For example, if the UE 115 receives SCI supporting sharing (for example, the SCI is related to a first hop 205 and includes a “1” bit value for the 1-bit COT sharing indicator) , the UE 115 may transmit a sidelink message in the COT. Furthermore, if the UE 115 is a served UE 115, such as the UE 115-b, and the SCI is related to a first hop 205, such as the hop 205-a, the UE 115-b may receive a sidelink data message from the UE 115-a and, if configured for feedback, may transmit a sidelink feedback message in response on the PSFCH (for example, in the COT using sidelink COT sharing) . In some implementations, the UE 115-b may share the COT for communications with additional UEs 115, such as a UE 115-c. For example, the UE 115-b may use the COT to transmit a message on the PSCCH, the PSSCH, or both to a UE 115-c. However, as this is a second hop 205, the UE 115-b may not expect a corresponding feedback message on the PSFCH from the UE 115-c. If the UE 115 is a non-served UE 115, such as the UE 115-e, the UE 115-e may detect the SCI related to the first hop 205, such as the hop 205-d, and may refrain from transmitting a corresponding feedback message on the PSFCH (for example, based on the SCI further indicating one or more served UEs 115 not including the UE 115-e) . However, similar to the UE 115-b and based on the COT sharing indicator in the SCI, the UE 115-e may use the COT to transmit a message on the PSCCH, the PSSCH, or both to a UE 115-f. For both UEs 115-b and 115-e, the UEs 115 may update the COT sharing indicator for transmission. For example, the UEs 115-b and 115-e may set the COT sharing indicator to “0” for sidelink transmissions (for example, in a PSCCH or PSSCH message) in the shared COT. In some implementations, the UEs 115-c and 115-f may receive SCI related to the second hops 205-b and hop 205-e, respectively. For two-hop COT sharing, the UEs 115-c and 115-f may detect the SCI related to the second hops 205-b and 205-e and may refrain from further sharing the COT (for example, based on the COT sharing indicator of “0” ) . Refraining from further sharing the COT may involve refraining from transmitting a feedback message on the PSFCH (for example, even if the corresponding PSFCH is configured) , refraining from transmitting a control message on the PSCCH, and refraining from transmitting a control or data message on the PSSCH to any other UEs 115 in the COT.

In some implementations, the wireless communications system 200 may support multi-hop COT sharing for sidelink communications (for example, for NR-U sidelink) . Multi-hop sidelink COT sharing may involve a threshold number of hops 205 between UEs 115. For example, as illustrated in Figure 2, the UEs 115 may implement a threshold number of hops 205 of three. That is, a UE 115-a may be able to share a COT with a UE 115-b, the UE 115-b may further share the COT with a UE 115-c, and the UE 115-c may further share the COT with a UE 115-d, but the UE 115-d may not further share the COT based on the threshold number of hops 205 being three (for example, corresponding to a hop 205-a, a hop 205-b, and a hop 205-c) . In some implementations, the threshold number of hops 205 may be configured (for example, by a base station 105 or by the UE 115 initially gaining access to the sidelink channel) or pre-configured for the UEs 115.

In some examples, to track the number of hops 205, the SCI may include a hop counter in a COT sharing field of a sidelink control message. In some implementations, the hop counter may indicate a remaining number of hops for COT sharing. For example, the UE 115-a initiating the COT sharing may set the hop counter in a sidelink control message to one less than the threshold number of hops 205. A UE 115 may receive the sidelink control message and determine that sharing of the COT is supported based on the hop counter being greater than 0. For example, if the UE 115-b receives a sidelink message from the UE 115-awith a COT sharing hop counter set to X (for example, 2) , the UE 115-b may share the COT to a UE 115-c and may update (for example, decrement) the hop counter to X–1 (for example, 1) for the sidelink transmission to the UE 115-c. Similarly, the UE 115-c may receive SCI from the UE 115-b, determine that the hop counter is 1, and may determine that further sharing of the COT is supported. The UE 115-c may update the hop counter to 0 in a sidelink message transmission to a UE 115-d via a hop 205-c. The UE 115-d may detect the sidelink message from the UE 115-c with the COT sharing hop counter of 0 and may refrain from further sharing of the COT based on the hop counter value being equal to 0. In some other implementations, the UE 115-a may set the hop counter to 1 and each successive UE 115 sharing the COT may increment the hop counter. In such implementations, if a UE 115 receives SCI with a hop counter equal to the threshold number of hops, the UE 115 may refrain from sharing the COT further. In some examples, the first hop 205 (for example, the hop 205-a) may support sharing of the COT for PSFCH feedback, and no further hops 205 may support feedback messaging in the COT. In some other examples, each hop 205 of the COT may support PSFCH feedback other than the final hop 205 (for example, the hop 205-c) .

Figure 3 illustrates an example of a wireless communications system 300 that supports hop-based COT sharing. In some examples, the wireless communications system 300 may implement aspects of a

wireless communications systems

100 or 200. The wireless communications system 300 may include a UE 115-g, a UE 115-h, a UE 115-i, a UE 115-j, and a UE 115-k, which may be examples of UEs 115 described with reference to Figures 1 and 2. Additionally, the wireless communications system 300 may include a hop 305-a, a hop 305-b, and a hop 305-c, which may be examples of hops 205 as described with reference to Figure 2. For example, the UE 115-g may transmit a sidelink message in a first hop 305-a, which may include COT sharing information. Sharing a COT with additional UEs 115 may increase efficiency in the system by improving sidelink channel access and resource allocation at the UEs 115.

In some implementations, a UE 115-g may perform distance-based COT sharing in combination with hop-based COT sharing. Distance-based COT sharing may be based on location information for one or more nodes, such as the UE 115-g, the UE 115-h, the UE 115-i, the UE 115-j, the UE 115-k, or some combination of these nodes. In some implementations, the location information may be a geographical, or global positioning system (GPS) , location. Using such location information, the UEs 115 may perform COT sharing based on the approximate distance between nodes, the number of hops, or both. In some examples, a base station 105 may configure one or more UEs 115 with a distance threshold 315 supporting COT sharing, for example, using an RRC configuration message. In some other examples, a UE 115, such as the UE 115-g, may dynamically or semi-statically select a distance threshold 315 for COT sharing and may indicate the selected distance threshold 315 to other UEs 115 (for example, in SCI) . In yet some other examples, the UEs 115 may be pre-configured with a distance threshold 315 for COT sharing. The distance threshold 315 for COT sharing may be defined with respect to a source node, such as the UE 115 that initially gains access to the sidelink channel for the COT. As illustrated in Figure 3, the UE 115-g may gain access to the sidelink channel for a COT and, correspondingly, may act as the source node for sharing the COT.

UEs 115 may include the source node identifier for the COT in SCI. For example, an SCI-1 or SCI-2 message may include an additional field indicating a source node identifier (for example, a UE identifier) . Additionally, or alternatively, the SCI message may include location information for the source node. As illustrated in Figure 3, the UE 115-g may be the source node for possible COT sharing with a UE 115-h, a UE 115-i, a UE 115-j, and a UE 115-k. The UE 115-g may forward source identifier information (indicating the UE 115-g) in an SCI field of a sidelink transmission to the UE 115-h in a hop 305-a. If the UE 115-h determines to share the COT, the UE 115-h may continue to forward the source identifier information associated with the UE 115-g in SCI to a next UE 115-i. In some examples, node location information may be pre-propagated such that the UEs 115-h, 115-i, 115-j, and 115-k may determine the location of the source node, the UE 115-g, to determine if the COT is shareable according to distance-based COT sharing parameters.

For example, a UE 115-g may share a COT with a UE 115-h, where the UE 115-g may send SCI to the UE 115-h with a hop counter greater than 0 (for example, 3) and an indication of the UE 115-g as the source node. The UE 115-h may identify a distance threshold 315 based on a configuration of the UEs 115 or based on a parameter indicated in the SCI. The UE 115-h may determine a distance between the source node, the UE 115-g, and the UE 115-h and may compare the determined distance to the distance threshold 315. If the UE 115-h is positioned closer than the distance threshold 315 from the UE 115-g (and all other COT sharing criteria is met, such as the hop counter is greater than 0) , the UE 115-h may share the COT with a UE 115-i in a hop 305-b. When sharing the COT, the UE 115-h may update (for example, decrement) the hop counter and include the updated hop counter (for example, 2) in SCI, along with an indication of the UE 115-g as the source node. Similarly, the UE 115-i may receive the hop counter and the source node identifier information, check both to ensure that the hop counter is greater than 0 and the UE 115-i is within the distance threshold 315 from the UE 115-g, and determine that the COT is further sharable based on both distance-based COT sharing and hop-based COT sharing. The UE 115-i may decrement the hop counter (for example, to 1) and transmit SCI to share the COT with a UE 115-j in a hop 305-c. The UE 115-j may receive the SCI including the updated hop counter and the source node indicator and may determine whether further sharing of the COT is supported. In some examples, the hop counter may be greater than 0, but the distance between UE 115-j and the source UE 115-g may be greater than the distance threshold 315. As such, in some implementations, the UE 115-j may not share the COT with any further UEs 115, such as a UE 115-k (as illustrated at 310) . In such implementations, each UE 115 may check both the distance threshold 315 and the hop counter criteria for COT sharing support, and if either fails the check (for example, the UE 115 is farther than the distance threshold 315 from the source UE 115 or the hop counter is equal to 0) , the UE 115 may refrain from sharing the COT further.

In some other implementations, the UEs 115 may share the COT if any of the COT sharing criteria is met. For example, a UE 115 may check both the distance threshold 315 and the hop counter criteria for COT sharing support, and if either passes the check (for example, the UE 115 is closer than the distance threshold 315 from the source UE 115 or the hop counter is greater than 0) , the UE 115 may share the COT further. For example, the UE 115-g may share a COT with the UE 115-h, and the UE 115-h may share the COT with the UE 115-i in a hop 305-b based on checking that the hop counter is greater than 0 or the distance threshold 305 is met. In some examples, the UE 115-h may decrement the hop counter to 0 when sharing the COT. The UE 115-i may receive the hop counter and source node identifier in the SCI. The UE 115-i may check the hop counter and determine that the value is not greater than 0. However, the distance threshold 315 may still be met, as UE 115-i may be closer than the distance threshold 315 from the source UE 115-g. Because at least one of the criteria is met, the UE 115-i may further share the COT with the UE 115-j in a hop 305-c. When transmitting the SCI in the shared COT, the UE 115-i may maintain the hop counter to still be equal to 0 (rather than further decrementing the hop counter) . Accordingly, at the UE 115-j, the hop counter may still be 0 and the distance threshold 315 may be exceeded, because the distance between the UE 115-j and the source UE 115-g may be greater than the distance threshold 315. Thus, the UE 115-j may not share the COT with the UE 115-k based on both criteria failing (as illustrated at 310) . In such implementations, each UE 115 may check both the distance threshold 315 and the hop counter criteria for COT sharing support, and if both fail the check (for example, the UE 115 is farther than the distance threshold 315 from the source UE 115 and the hop counter is equal to 0) , the UE 115 may refrain from sharing the COT further.

Figure 4 illustrates an example of a wireless communications system 400 that supports hop-based COT sharing. In some examples, the wireless communications system 400 may implement aspects of a

wireless communications systems

100, 200, or 300. The wireless communications system 400 may include UEs 115-l, 115-m, 115-n, 115-o, and 115-p, a base station 105-a with a coverage area 110-a, and a communication link 125-a, which may be examples of UEs 115, a base station 105 with a coverage area 110, and a communication link 125 described with reference to Figure 1. The wireless communications system 400 may support group-based COT sharing (for example, in addition or alternative to hop-based COT sharing, distance-based COT sharing, or both) . For example, a UE 115 may check a sharing bit indicator, a hop counter, a threshold distance, a group identifier, or any combination thereof when determining whether a COT supports sharing. The UEs 115 may be grouped into a set of UE groups 405 for hop-based sharing. In some implementations, the base station 105-a may group the UEs 115 in the coverage area 110-a. Sharing a COT with a subset of UEs 115 in a coverage area 110-a according to a UE group 405 may allow for more accurate control of COT sharing, which may increase efficiency in the system by improving sidelink channel access and resource allocation for the grouped UEs 115.

In some implementations, the UEs 115 may be grouped according to group indexes. For example, the base station 105-a may group a UE 115-n, a UE 115-o, and a UE 115-p into a UE group 405-a and may group a UE 115-l and a UE 115-m into a UE group 405-b. In some examples, the UEs 115 may be RRC configured with one or more group indexes. For example, the group index for the UE 115-l and the UE 115-m may be different from the group index for the UE 115-n, the UE 115-o, and the UE 115-p. In some examples, a UE 115 may belong to zero groups or one or more groups. In some implementations, the UE groups 405 may be determined at an application level. For example, UEs 115 may be grouped according to a service, a carrier, an operator, a manufacturer, a user, or any combination thereof.

Group-based COT sharing may reduce the number of candidate UEs 115 for sharing a COT based on the UE groups 405. Such a reduction in candidate UEs 115 may improve control over how the COT is shared for sidelink communications. In some examples, the UE 115-n may transmit a sidelink message to the UE 115-o. For example, the sidelink message may be a sidelink control message including SCI. The SCI may include a group identifier to indicate with which UEs 115 the COT may be shared. For example, the group identifier may indicate the group 405-a, including the UE 115-n, the UE 115-o, and the UE 115-p. In some implementations, if the UE 115-n transmits a sidelink message sharing the COT with the UE 115-o in a first hop, the UE 115-o may share the COT with the UE 115-p in a second hop (for example, based on the group identifier in the SCI) . For example, the UE 115-o may determine that the COT supports sharing by the UE 115-o to the UE 115-p based on the UE 115-o having a group index that matches the group index in the SCI, the UE 115-p having a group index that matches the group index in the SCI, or both. The UE 115-o may forward the group identifier in SCI for the second hop. In some examples, a UE 115 addressed by the SCI may share the COT regardless of the group index.

In some other implementations, each UE 115 may be configured (for example, by the base station 105-a or some other configuration technique) with a list of UE identifiers for UEs 115 in the same group as the respective UE 115. For example, the UE 115-n may receive a list of UE identifiers corresponding to the UE 115-o and the UE 115-p. Similarly, the UE 115-o may receive a list of UE identifiers corresponding to the UE 115-n and the UE 115-p, and the UE 115-p may receive a list of UE identifiers corresponding to the UE 115-n and the UE 115-o. The UE 115-n may transmit SCI to the UE 115-o sharing a COT in a first hop. A UE 115 detecting this sidelink message may compare the source UE, the destination UE, or both to a configured list of UE identifiers. For example, the SCI may include an indication of the source UE 115-n, the destination UE 115-o, or both. If the UE 115-p detects the SCI, the UE 115-p may compare the UE identifier for the source UE 115-n, the UE identifier for the destination UE 115-p, or both to the list of UE identifiers (for example, the group identifier list) configured at the UE 115-p. If one or both of the UE identifiers match the list of UE identifiers (for example, if the source UE 115, the destination UE 115, or both are in the same UE group 405 as the UE 115 receiving the SCI) , the UE 115-p may determine that the SCI supports COT sharing for the UE group 405-a and may transmit a sidelink message in the COT. The group-based COT sharing may support sending sidelink messages to other UEs 115 in the same UE group 405-a. In some examples, a UE 115 may determine that COT sharing is not supported if one of the source UE 115 or the destination UE 115 does not share the UE’s group or may determine that COT sharing is not supported if both the source UE 115 and the destination UE 115 do not share the UE’s group.

Figure 5 illustrates an example of a process flow 500 that supports hop-based COT sharing. In some examples, the process flow 500 may implement aspects of a

wireless communications systems

100, 200, 300, or 400. The process flow 500 may illustrate an example of a COT sharing process for a UE 115-q, a UE 115-r, and a UE 115-s. Alternative examples of the following may be implemented, where some processes are performed in a different order than described or are not performed at all. In some implementations, processes may include additional features not mentioned below, or further processes may be added. For example, although UEs 115 are shown, the same process may apply to access points (APs) or base stations.

At 505, the UE 115-r may receive a sidelink control message from the UE 115-q. In some examples, the UE 115-q may be the source node for sharing a COT. In some implementations, the sidelink control message may include sharing information for a COT of a communication link. For example, the sidelink control message may include a sharing indicator, a hop counter, a threshold distance supporting COT sharing, a group identifier, or a combination thereof. Additionally, or alternatively, the sidelink control message may include an indication of the source UE 115-q. In some implementations, the sidelink control message may include a bit indicating if the sidelink control message supports sharing of the COT. In some implementations, the sidelink control message may include an SCI-1 message on a PSCCH, a SCI-2 message on a PSSCH, or both.

At 510, the UE 115-r may determine a group identifier associated with the sidelink control message. In some implementations, the UE 115-r may belong to one or more groups of UEs 115. The UE 115-r may share a COT with the UEs 115 in the one or more groups. In some examples, the sidelink control message may include the group identifier. In some other examples, the UE 115-r may determine the group identifier based on a source UE 115-q, the UE 115-r, such as a UE 115 served by the sidelink control message, or both. In some examples, the UE 115-r may receive an RRC message indicating the group identifier for the UE 115-r, a list of UEs 115 corresponding to the group identifier, or both.

In some implementations, the sidelink control message may include a hop counter indicating a number of consecutive devices sharing the COT. At 515, the UE 115-r may compare the hop counter to a threshold number of hops (for example, 0 hops) . Additionally, or alternatively, at 520, the UE 115-r may identify a threshold distance supporting sharing of the COT. At 525, the UE 115-r may determine a distance between the source UE 115-q (for example, the source node for sharing the COT) and the UE 115-r, a distance between the source the UE 115-q and a target UE 115-sfor sharing, or both. At 530, the UE 115-r may compare a determined distance to the threshold distance. In some implementations, the UE 115-r may receive an RRC configuration message, for example, from a base station, indicating the threshold distance supporting sharing of the COT. In some examples, the UE 115-r may determine location information for the source UE 115-q, the UE 115-r, the UE 115-s, or a combination to use for determining distance-based COT sharing.

At 535, the UE 115-r may determine whether to share the COT with the UE 115-q based on the sidelink control message received at 505. For example, UE 115-r may determine to share the COT based on the sharing information in the sidelink control message. That is, if the hop counter satisfies the threshold number of hops, the distance between the source UE 115-q and the UE 115-s or the UE 115-r satisfies a distance threshold, the group identifier corresponds to the correct group (for example, the group that contains the UE 115-q, the UE 115-r, the UE 115-s, or a combination thereof) , or a combination, the UE 115-r may determine to share the COT. For example, the UE 115-r may further share the COT with the UE 115-s. In some implementations, the sidelink control message may serve a different UE 115 than the UE 115-r.

At 540, the UE 115-r may update the hop counter based on determining to share the COT. For example, the UE 115-r may increment the hop counter or decrement the hop counter to indicate a next hop (for example, to the UE 115-s) .

At 545, the UE 115-r may receive a signal, transmit a signal, or both over the communication link within the COT based on determining whether to share the COT. In some implementations, such as when the UE 115-q is the source node, the UE 115-r may receive a sidelink data message within the COT based on the sidelink control message received at 505. The UE 115-r may output a feedback message in response to the sidelink data message, such as an ACK or a NACK, based on the sidelink control message supporting sharing the COT with the UE 115-q.

At 550, the UE 115-r may output a sidelink message to the UE 115-sbased on the sidelink control message received at 505 supporting COT sharing. In some implementations, the sidelink message may be a sidelink control message, and may include sharing information, such as a distance threshold, a hop counter, a group identifier, or a combination. In some implementations, the sidelink message may include an indication of the source UE 115-q.

Figure 6 illustrates an example of a process flow 600 that supports hop-based COT sharing. In some examples, the process flow 600 may implement aspects of a

wireless communications systems

100, 200, 300, or 400. The process flow 600 may illustrate an example of a COT sharing process for a UE 115-t and a UE 115-u. Alternative examples of the following may be implemented, where some processes are performed in a different order than described or are not performed at all. In some implementations, processes may include additional features not mentioned below, or further processes may be added. For example, although UEs 115 are shown, the same process may apply to APs or base stations.

At 605, the UE 115-u may receive a sidelink control message from the UE 115-t. In some examples, the UE 115-t may be the source node for sharing the COT. In some implementations, the sidelink control message may include sharing information for a COT of a communication link. For example, the sidelink control message may include a hop counter, a threshold distance supporting COT sharing, a group identifier, or a combination thereof. Additionally, or alternatively, the sidelink control message may include an indication of the source UE 115-t. In some implementations, the sidelink control message may include a bit indicating if the sidelink control message supports sharing of the COT. In some implementations, the sidelink control message may include an SCI-1 message on a PSCCH, a SCI-2 message on a PSSCH, or both.

At 610, the UE 115-u may determine a group identifier associated with the sidelink control message. In some implementations, the UE 115-u may belong to one or more groups of UEs 115. The UE 115-u may share a COT with the UEs 115 in the one or more groups. In some examples, the sidelink control message may include the group identifier. In some other examples, the UE 115-u may determine the group identifier based on the source UE 115-t, the UE 115-u, such as a UE 115 served by the sidelink control message, or both. In some examples, the UE 115-u may receive an RRC message indicating the group identifier for the UE 115-u, a list of UEs 115 corresponding to the group identifier, or both.

In some implementations, the sidelink control message may include a hop counter indicating a number of consecutive devices sharing the COT. At 615, the UE 115-u may compare the hop counter to a threshold number of hops (for example, 0 hops) . Additionally, or alternatively, at 620, the UE 115-u may identify a threshold distance supporting sharing of the COT. At 625, the UE 115-u may determine a distance between the source UE 115-t (for example, the source node for sharing the COT) and the UE 115-u. At 630, the UE 115-u may compare the determined distance to the threshold distance. In some implementations, the UE 115-u may receive an RRC configuration message, for example, from a base station, indicating the threshold distance supporting sharing of the COT.

At 635, the UE 115-u may determine whether to share the COT with one or more UEs 115 based on the sidelink control message received at 605. For example, the UE 115-u may determine not to share the COT with the UE 115-t based on the sharing information in the sidelink control message. That is, if the hop counter does not satisfy the threshold number of hops (for example, if the hop counter equals 0) , the distance between the source UE 115-t and the UE 115-u does not satisfy a distance threshold (for example, the UE 115-u is beyond the threshold distance from the source UE 115-t) , the group identifier corresponds to a different group (for example, a group that does not contain the UE 115-u) , or a combination, the UE 115-u may refrain from sharing the COT. In some implementations, the sidelink control message may serve a different UE 115 than the UE 115-u.

At 640, the UE 115-u may refrain from outputting a sidelink message to another UE 115 within the COT based on determining not to share the COT.

At 645, the UE 115-u may receive a signal over the communication link within the COT based on determining whether to share the COT. In some implementations, the UE 115-u may receive a sidelink data message within the COT based on the sidelink control message received at 605. The UE 115-u may refrain from outputting a feedback data message, such as an ACK or a NACK, to the UE 115-t based on determining not to share the COT.

Figure 7 shows a block diagram 700 of an example device 705 that supports hop-based COT sharing. The device 705 may be an example of or include the components of a UE 115 as described herein. The device 705 may include components for bi-directional voice and data communications including components for transmitting and receiving communications, including a communications manager 710, an input/output (I/O) controller 715, a transceiver 720, an antenna 725, memory 730, and a processor 740. These components may be in electronic communication via one or more buses, such as a bus 745. The communications manager 710 may be implemented at a first device.

In some implementations, the communications manager 710 may receive a sidelink control message from a second device, the sidelink control message including sharing information for a COT of a communication link, determine whether the first device is one of a set of devices with which the second device shares the COT based on the sidelink control message, and communicate over the communication link within the COT based on the determining.

Additionally, or alternatively, the communications manager 710 may gain access to a communication link for a COT, generate a sidelink control message, the sidelink control message including sharing information for the COT of the communication link, and transmit the sidelink control message to a second device, where the sidelink control message indicates whether the second device is one of a set of devices with which the first device shares the COT based on the sharing information.

The I/O controller 715 may manage input and output signals for the device 705. The I/O controller 715 also may manage peripherals not integrated into the device 705. In some implementations, the I/O controller 715 may represent a physical connection or port to an external peripheral. In some implementations, the I/O controller 715 may utilize an operating system such as

or another known operating system. In some other implementations, the I/O controller 715 may represent or interact with a modem, a keyboard, a mouse, a touchscreen, or a similar device. In some implementations, the I/O controller 715 may be implemented as part of a processor. In some implementations, a user may interact with the device 705 via the I/O controller 715 or via hardware components controlled by the I/O controller 715.

The transceiver 720 may communicate bi-directionally, via one or more antennas, wired, or wireless links as described above. For example, the transceiver 720 may represent a wireless transceiver and may communicate bi-directionally with another wireless transceiver. The transceiver 720 also may include a modem to modulate the packets and provide the modulated packets to the antennas for transmission, and to demodulate packets received from the antennas.

In some implementations, the wireless device may include a single antenna 725. However, in some other implementations the device may have more than one antenna 725, which may be capable of concurrently transmitting or receiving multiple wireless transmissions.

The memory 730 may include random-access memory (RAM) and read-only memory (ROM) . The memory 730 may store computer-readable, computer-executable code 735 including instructions that, when executed, cause the processor to perform various functions described herein. In some implementations, the memory 730 may contain, among other things, a basic I/O system (BIOS) which may control basic hardware or software operation such as the interaction with peripheral components or devices.

The processor 740 may include an intelligent hardware device, such as a general-purpose processor, a digital signal processor (DSP) , a central processing unit (CPU) , a microcontroller, an application-specific integrated circuit (ASIC) , a field-programmable gate array (FPGA) , a programmable logic device, a discrete gate or transistor logic component, a discrete hardware component, or any combination thereof. In some implementations, the processor 740 may be configured to operate a memory array using a memory controller. In some other implementations, a memory controller may be integrated into the processor 740. The processor 740 may be configured to execute computer-readable instructions stored in a memory 730 to cause the device 705 to perform various functions, such as functions or tasks supporting hop-based COT sharing.

In some implementations, the processor 740 may be a component of a processing system. A processing system may generally refer to a system or series of machines or components that receives inputs and processes the inputs to produce a set of outputs (which may be passed to other systems or components of, for example, the device 705, such as a UE 115, a base station 105, an access point, a station, or different device) . For example, a processing system of the device 705 may refer to a system including the various other components or subcomponents of the device 875.

The processing system of the device 705 may interface with other components of the device 705, and may process information received from other components (such as inputs or signals) , output information to other components, etc. For example, a chip or modem of the device 705 may include a processing system, a first interface to receive information, and a second interface to output information. In some examples, the first interface may refer to an interface between the processing system of the chip or modem and a receiver, such that the device 705 may receive information or signal inputs, and the information may be passed to the processing system. In some examples, the second interface may refer to an interface between the processing system of the chip or modem and a transmitter, such that the device 705 may transmit information output from the chip or modem. A person having ordinary skill in the art will readily recognize that the second interface also may receive information or signal inputs, and the first interface also may transmit information.

The code 735 may include instructions to implement aspects of the present disclosure, including instructions to support wireless communications. The code 735 may be stored in a non-transitory computer-readable medium such as system memory or other type of memory. In some implementations, the code 735 may not be directly executable by the processor 740 but may cause a computer-when compiled and executed-to perform functions described herein.

Figure 8 shows a flowchart illustrating an example method 800 that supports hop-based COT sharing. The operations of the method 800 may be implemented by a UE 115 or its components as described herein. For example, the operations of the method 800 may be performed by a communications manager as described with reference to Figure 7. In some examples, a UE 115 may execute a set of instructions to control the functional elements of the UE 115 to perform the functions described below. Additionally, or alternatively, a UE 115 may perform aspects of the functions described below using special-purpose hardware.

At 805, the UE 115 (for example, a first device) may receive a sidelink control message from a second device, the sidelink control message including sharing information for a COT of a communication link. The operations of 805 may be performed according to the methods described herein.

At 810, the UE 115 may determine whether the UE 115 is one of a set of devices with which the second device shares the COT based on the sidelink control message. The operations of 810 may be performed according to the methods described herein.

At 815, the UE 115 may communicate over the communication link within the COT based on the determining. The operations of 815 may be performed according to the methods described herein.

Figure 9 shows a flowchart illustrating an example method 900 that supports hop-based COT sharing. The operations of the method 900 may be implemented by a UE 115 or its components as described herein. For example, the operations of the method 900 may be performed by a communications manager as described with reference to Figure 7. In some examples, a UE 115 may execute a set of instructions to control the functional elements of the UE 115 to perform the functions described below. Additionally, or alternatively, a UE 115 may perform aspects of the functions described below using special-purpose hardware.

At 905, the UE 115 (for example, a first device) may receive a sidelink control message from a second device, the sidelink control message including sharing information for a COT of a communication link. The operations of 905 may be performed according to the methods described herein.

At 910, the UE 115 may determine that the sidelink control message supports the second device sharing the COT with the UE 115 based on the sharing information for the COT. The operations of 910 may be performed according to the methods described herein.

At 915, the UE 115 may transmit a sidelink message to a third device of the set of devices different from the second device within the COT based on the sidelink control message supporting the second device sharing the COT with the UE 115. The operations of 915 may be performed according to the methods described herein.

Figure 10 shows a flowchart illustrating an example method 1000 that supports hop-based COT sharing. The operations of the method 1000 may be implemented by a UE 115 or its components as described herein. For example, the operations of the method 1000 may be performed by a communications manager as described with reference to Figure 7. In some examples, a UE 115 may execute a set of instructions to control the functional elements of the UE 115 to perform the functions described below. Additionally, or alternatively, a UE 115 may perform aspects of the functions described below using special-purpose hardware.

At 1005, the UE 115 (for example, a first device) may receive a sidelink control message from a second device, the sidelink control message including sharing information for a COT of a communication link. The operations of 1005 may be performed according to the methods described herein.

At 1010, the UE 115 may determine that the sidelink control message supports the second device sharing the COT with the UE 115 based on the sharing information for the COT. The operations of 1010 may be performed according to the methods described herein.

At 1015, the UE 115 may receive a sidelink data message from the second device within the COT based on the sidelink control message. The operations of 1015 may be performed according to the methods described herein.

At 1020, the UE 115 may transmit a feedback message to the second device within the COT in response to the sidelink data message based on the sidelink control message supporting the second device sharing the COT with the UE 115 and the second device corresponding to a source node for sharing the COT. The operations of 1020 may be performed according to the methods described herein.

Figure 11 shows a flowchart illustrating an example method 1100 that supports hop-based COT sharing. The operations of the method 1100 may be implemented by a UE 115 or its components as described herein. For example, the operations of the method 1100 may be performed by a communications manager as described with reference to Figure 7. In some examples, a UE 115 may execute a set of instructions to control the functional elements of the UE 115 to perform the functions described below. Additionally, or alternatively, a UE 115 may perform aspects of the functions described below using special-purpose hardware.

At 1105, the UE 115 (for example, a first device) may receive a sidelink control message from a second device, the sidelink control message including sharing information for a COT of a communication link. The operations of 1105 may be performed according to the methods described herein.

At 1110, the UE 115 may determine that the sidelink control message restricts the second device from sharing the COT with the UE 115 based on the sharing information for the COT. The operations of 1110 may be performed according to the methods described herein.

At 1115, the UE 115 may receive a sidelink data message from the second device within the COT based on the sidelink control message. The operations of 1115 may be performed according to the methods described herein.

At 1120, the UE 115 may refrain from transmitting a sidelink message within the COT based on the sidelink control message restricting the second device from sharing the COT with the UE 115. The operations of 1120 may be performed according to the methods described herein.

Figure 12 shows a flowchart illustrating an example method 1200 that supports hop-based COT sharing. The operations of the method 1200 may be implemented by a UE 115 or its components as described herein. For example, the operations of the method 1200 may be performed by a communications manager as described with reference to Figure 7. In some examples, a UE 115 may execute a set of instructions to control the functional elements of the UE 115 to perform the functions described below. Additionally, or alternatively, a UE 115 may perform aspects of the functions described below using special-purpose hardware.

At 1205, the UE 115 (for example, a first device) may gain access to a communication link for a COT. The operations of 1205 may be performed according to the methods described herein.

At 1210, the UE 115 may generate a sidelink control message, the sidelink control message including sharing information for the COT of the communication link. The operations of 1210 may be performed according to the methods described herein.

At 1215, the UE 115 may transmit the sidelink control message to a second device, where the sidelink control message indicates whether the second device is one of a set of devices with which the UE 115 shares the COT based on the sharing information. The operations of 1215 may be performed according to the methods described herein.

As used herein, a phrase referring to “at least one of” a list of items refers to any combination of those items, including single members. As an example, “at least one of: a, b, or c” is intended to cover: a, b, c, a-b, a-c, b-c, and a-b-c.

The various illustrative logics, logical blocks, modules, circuits and algorithm processes described in connection with the implementations disclosed herein may be implemented as electronic hardware, computer software, or combinations of both. The interchangeability of hardware and software has been described generally, in terms of functionality, and illustrated in the various illustrative components, blocks, modules, circuits and processes described above. Whether such functionality is implemented in hardware or software depends upon the particular application and design constraints imposed on the overall system.

The hardware and data processing apparatus used to implement the various illustrative logics, logical blocks, modules and circuits described in connection with the aspects disclosed herein may be implemented or performed with a general purpose single-or multi-chip processor, a DSP, an ASIC, an FPGA or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. A general-purpose processor may be a microprocessor, or, any conventional processor, controller, microcontroller, or state machine. A processor also may be implemented as a combination of computing devices, such as a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration. In some implementations, particular processes and methods may be performed by circuitry that is specific to a given function.

In one or more aspects, the functions described may be implemented in hardware, digital electronic circuitry, computer software, firmware, including the structures disclosed in this specification and their structural equivalents thereof, or in any combination thereof. Implementations of the subject matter described in this specification also can be implemented as one or more computer programs, such as one or more modules of computer program instructions, encoded on a computer storage media for execution by, or to control the operation of, data processing apparatus.

If implemented in software, the functions may be stored on or transmitted over as one or more instructions or code on a computer-readable medium. The processes of a method or algorithm disclosed herein may be implemented in a processor-executable software module which may reside on a computer-readable medium. Computer-readable media includes both computer storage media and communication media including any medium that can be enabled to transfer a computer program from one place to another. A storage media may be any available media that may be accessed by a computer. By way of example, and not limitation, such computer-readable media may include RAM, ROM, electrically erasable programmable ROM (EEPROM) , compact disc (CD) -ROM or other optical disk storage, magnetic disk storage or other magnetic storage devices, or any other medium that may be used to store desired program code in the form of instructions or data structures and that may be accessed by a computer. Also, any connection can be properly termed a computer-readable medium. Disk and disc, as used herein, includes CD, laser disc, optical disc, digital versatile disc (DVD) , floppy disk, and Blu-ray disc where disks usually reproduce data magnetically, while discs reproduce data optically with lasers. Combinations of the above should also be included within the scope of computer-readable media. Additionally, the operations of a method or algorithm may reside as one or any combination or set of codes and instructions on a machine readable medium and computer-readable medium, which may be incorporated into a computer program product.

Various modifications to the implementations described in this disclosure may be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other implementations without departing from the spirit or scope of this disclosure. Thus, the claims are not intended to be limited to the implementations shown herein, but are to be accorded the widest scope consistent with this disclosure, the principles and the novel features disclosed herein.

Additionally, a person having ordinary skill in the art will readily appreciate, the terms “upper” and “lower” are sometimes used for ease of describing the figures, and indicate relative positions corresponding to the orientation of the figure on a properly oriented page, and may not reflect the proper orientation of any device as implemented.

Certain features that are described in this specification in the context of separate implementations also can be implemented in combination in a single implementation. Conversely, various features that are described in the context of a single implementation also can be implemented in multiple implementations separately or in any suitable subcombination. Moreover, although features may be described above as acting in certain combinations and even initially claimed as such, one or more features from a claimed combination can in some examples be excised from the combination, and the claimed combination may be directed to a subcombination or variation of a subcombination.

Similarly, while operations are depicted in the drawings in a particular order, this should not be understood as requiring that such operations be performed in the particular order shown or in sequential order, or that all illustrated operations be performed, to achieve desirable results. Further, the drawings may schematically depict one more example processes in the form of a flow diagram. However, other operations that are not depicted can be incorporated in the example processes that are schematically illustrated. For example, one or more additional operations can be performed before, after, simultaneously, or between any of the illustrated operations. In certain circumstances, multitasking and parallel processing may be advantageous. Moreover, the separation of various system components in the implementations described above should not be understood as requiring such separation in all implementations, and it should be understood that the described program components and systems can generally be integrated together in a single software product or packaged into multiple software products. Additionally, other implementations are within the scope of the following claims. In some examples, the actions recited in the claims can be performed in a different order and still achieve desirable results.

Claims

An apparatus for wireless communications, comprising:

a first interface configured to:

obtain a sidelink control message sent from a device, the sidelink control message comprising sharing information for a channel occupancy time (COT) of a communication link;

a processing system configured to:

determine whether the apparatus corresponds to one of a plurality of devices with which the device shares the COT based at least in part on the sidelink control message; and

a second interface, wherein the first interface, the second interface, or a combination thereof is configured to:

obtain signaling, output signaling, or both based at least in part on the determining.
The apparatus of claim 1, wherein the processing system is further configured to:

determine that the sidelink control message supports the device sharing the COT with the apparatus based at least in part on the sharing information for the COT.
The apparatus of claim 2, wherein the second interface is further configured to:

output a sidelink message for transmission to a second device of the plurality of devices different from the device within the COT based at least in part on the sidelink control message supporting the device sharing the COT with the apparatus.
The apparatus of claim 3, wherein:

the sidelink control message comprises a hop counter indicating a number of devices sharing the COT, and the processing system is further configured to:

compare the hop counter to a threshold number of hops, wherein the sidelink control message is determined to support the device sharing the COT with the apparatus based at least in part on the comparing the hop counter to the threshold number of hops.
The apparatus of claim 4, wherein the processing system is further configured to:

update the hop counter, wherein the sidelink message output for transmission to the second device comprises the updated hop counter.
The apparatus of claim 5, wherein:

the updating comprises incrementing the hop counter or decrementing the hop counter.
The apparatus of claim 4, wherein the processing system is further configured to:

identify a threshold distance supporting sharing of the COT;

determine a distance between a source node for sharing the COT and the apparatus, the source node for sharing the COT and the second device, or a combination thereof; and

compare the determined distance to the threshold distance, wherein the sidelink control message is determined to support the device sharing the COT with the apparatus further based at least in part on the comparing the determined distance to the threshold distance.
The apparatus of claim 3, wherein the processing system is further configured to:

identify a threshold distance supporting sharing of the COT;

determine a distance between a source node for sharing the COT and the apparatus, the source node for sharing the COT and the second device, or a combination thereof; and

compare the determined distance to the threshold distance, wherein the sidelink control message is determined to support the device sharing the COT with the apparatus based at least in part on the comparing the determined distance to the threshold distance.
The apparatus of claim 8, wherein the first interface is further configured to:

obtain a radio resource control configuration message indicating the threshold distance supporting sharing of the COT.
The apparatus of claim 8, wherein:

the sidelink control message comprises a first indication of the source node; and

the sidelink message output for transmission to the second device comprises a second indication of the source node.
The apparatus of claim 8, wherein the processing system is further configured to:

determine location information for the source node, the apparatus, the second device, or a combination thereof based at least in part on the threshold distance supporting sharing of the COT.
The apparatus of claim 2, wherein:

the device corresponds to a source node for sharing the COT;

the first interface is further configured to:

obtain a sidelink data message sent from the device within the COT based at least in part on the sidelink control message; and

the second interface is further configured to:

output a feedback message for transmission to the device within the COT in response to the sidelink data message based at least in part on the sidelink control message supporting the device sharing the COT with the apparatus and the device corresponding to the source node.
The apparatus of claim 2, wherein:

the sidelink control message comprises a bit indicating if the sidelink control message supports sharing of the COT.
The apparatus of claim 2, wherein the processing system is further configured to:

determine that the sidelink control message serves a third device different from a device corresponding to the apparatus.
The apparatus of claim 1, wherein:

the processing system is further configured to:

determine that the sidelink control message restricts the device from sharing the COT with the apparatus based at least in part on the sharing information for the COT; and

the first interface is further configured to:

obtain a sidelink data message sent from the device within the COT based at least in part on the sidelink control message.
The apparatus of claim 15, wherein:

the sidelink control message comprises a hop counter indicating a number of devices sharing the COT; and

the processing system is further configured to:

compare the hop counter to a threshold number of hops, wherein the sidelink control message is determined to restrict the device from sharing the COT with the apparatus based at least in part on the hop counter corresponding to the threshold number of hops.
The apparatus of claim 15, wherein the processing system is further configured to:

identify a threshold distance supporting sharing of the COT;

determine a distance between a source node for sharing the COT and the apparatus; and

compare the determined distance to the threshold distance, wherein the sidelink control message is determined to restrict the device from sharing the COT with the apparatus based at least in part on the comparing the determined distance to the threshold distance.
The apparatus of claim 15, wherein the processing system is further configured to:

refrain from outputting a sidelink message for transmission within the COT via the second interface based at least in part on the sidelink control message restricting the device from sharing the COT with the apparatus.
The apparatus of claim 1, wherein:

the first interface is further configured to:

obtain a sidelink data message sent from the device within the COT based at least in part on the sidelink control message; and

the processing system is further configured to:

refrain from outputting a feedback message for transmission to the device within the COT via the second interface in response to the sidelink data message based at least in part on the device corresponding to a node subsequent to a source node for sharing the COT.
The apparatus of claim 1, wherein the processing system is further configured to:

determine a group identifier associated with the sidelink control message, wherein whether the apparatus corresponds to one of the plurality of devices with which the device shares the COT is determined based at least in part on the group identifier.
The apparatus of claim 20, wherein the second interface is further configured to:

output a sidelink message for transmission within the COT based at least in part on a group of devices corresponding to the group identifier comprising a device corresponding to the apparatus.
The apparatus of claim 21, wherein:

the sidelink message comprises the group identifier.
The apparatus of claim 20, wherein the processing system is further configured to:

refrain from outputting a sidelink message for transmission within the COT via the second interface based at least in part on a group of devices corresponding to the group identifier not comprising a device corresponding to the apparatus.
The apparatus of claim 20, wherein:

the sidelink control message comprises the group identifier.
The apparatus of claim 20, wherein the processing system is further configured to:

determine the group identifier based at least in part on a source node for sharing the COT, a device served by the sidelink control message, or a combination thereof.
The apparatus of claim 20, wherein the first interface is further configured to:

obtain a radio resource control configuration message indicating the group identifier for a device corresponding to the apparatus, a set of devices corresponding to the group identifier, or a combination thereof.
The apparatus of claim 1, wherein:

the sidelink control message comprises a first stage control message sent on a physical sidelink control channel, a second stage control message sent on a physical sidelink shared channel, or a combination thereof.
The apparatus of claim 1, wherein:

the device comprises a first user equipment (UE) , a first access point, a first base station, or a combination thereof; and

the apparatus corresponds to a second device comprising a second UE, a second access point, a second base station, or a combination thereof.
An apparatus for wireless communications, comprising:

a processing system configured to:

gain access to a communication link for a channel occupancy time (COT) ; and

generate a sidelink control message, the sidelink control message comprising sharing information for the COT of the communication link; and

a first interface configured to:

output the sidelink control message for transmission to a device, wherein the sidelink control message indicates whether the device is one of a plurality of devices with which the apparatus shares the COT based at least in part on the sharing information.
The apparatus of claim 29, wherein:

the first interface is further configured to:

output a sidelink data message for transmission to the device within the COT based at least in part on the sidelink control message; and

a second interface is configured to:

obtain a feedback message sent from the device within the COT in response to the sidelink data message based at least in part on the sidelink control message supporting the apparatus sharing the COT with the device and the apparatus corresponding to a source node for sharing the COT.
The apparatus of claim 29, wherein:

the sidelink control message comprises a hop counter indicating a number of devices sharing the COT, a bit indicating if the sidelink control message supports sharing of the COT, or a combination thereof; and

whether the device is one of the plurality of devices with which the apparatus shares the COT is based at least in part on the hop counter, the bit, or a combination thereof.
The apparatus of claim 29, wherein:

the sidelink control message comprises an indication of the apparatus as a source node for sharing the COT; and

whether the device is one of the plurality of devices with which the apparatus shares the COT is based at least in part on a distance from the source node.
The apparatus of claim 29, wherein:

the sidelink control message comprises a group identifier; and

whether the device is one of the plurality of devices with which the apparatus shares the COT is based at least in part on the group identifier.
The apparatus of claim 29, wherein:

the device comprises a first user equipment (UE) , a first access point, a first base station, or a combination thereof; and

the apparatus corresponds to a second device comprising a second UE, a second access point, a second base station, or a combination thereof.
A method for wireless communications at a first device, comprising:

receiving a sidelink control message from a second device, the sidelink control message comprising sharing information for a channel occupancy time (COT) of a communication link;

determining whether the first device is one of a plurality of devices with which the second device shares the COT based at least in part on the sidelink control message; and

communicating over the communication link within the COT based at least in part on the determining.
The method of claim 35, further comprising:

determining that the sidelink control message supports the second device sharing the COT with the first device based at least in part on the sharing information for the COT.
The method of claim 36, further comprising:

transmitting a sidelink message to a third device of the plurality of devices different from the second device within the COT based at least in part on the sidelink control message supporting the second device sharing the COT with the first device.
The method of claim 37, wherein:

the sidelink control message comprises a hop counter indicating a number of devices sharing the COT, the method further comprising:

comparing the hop counter to a threshold number of hops, wherein the sidelink control message is determined to support the second device sharing the COT with the first device based at least in part on the comparing the hop counter to the threshold number of hops.
The method of claim 38, further comprising:

updating the hop counter, wherein the sidelink message transmitted to the third device comprises the updated hop counter.
The method of claim 39, wherein:

the updating comprises incrementing the hop counter or decrementing the hop counter.
The method of claim 38, further comprising:

identifying a threshold distance supporting sharing of the COT;

determining a distance between a source node for sharing the COT and the first device, the source node for sharing the COT and the third device, or a combination thereof; and

comparing the determined distance to the threshold distance, wherein the sidelink control message is determined to support the second device sharing the COT with the first device further based at least in part on the comparing the determined distance to the threshold distance.
The method of claim 37, further comprising:

identifying a threshold distance supporting sharing of the COT;

determining a distance between a source node for sharing the COT and the first device, the source node for sharing the COT and the third device, or a combination thereof; and

comparing the determined distance to the threshold distance, wherein the sidelink control message is determined to support the second device sharing the COT with the first device based at least in part on the comparing the determined distance to the threshold distance.
The method of claim 42, further comprising:

receiving a radio resource control configuration message indicating the threshold distance supporting sharing of the COT.
The method of claim 42, wherein:

the sidelink control message comprises a first indication of the source node; and

the sidelink message transmitted to the third device comprises a second indication of the source node.
The method of claim 42, further comprising:

determining location information for the source node, the first device, the third device, or a combination thereof based at least in part on the threshold distance supporting sharing of the COT.
The method of claim 36, wherein:

the second device corresponds to a source node for sharing the COT and the communicating comprises:

receiving a sidelink data message from the second device within the COT based at least in part on the sidelink control message; and

transmitting a feedback message to the second device within the COT in response to the sidelink data message based at least in part on the sidelink control message supporting the second device sharing the COT with the first device and the second device corresponding to the source node.
The method of claim 36, wherein:

the sidelink control message comprises a bit indicating if the sidelink control message supports sharing of the COT.
The method of claim 36, further comprising:

determining that the sidelink control message serves a fourth device different from the first device.
The method of claim 35, further comprising:

determining that the sidelink control message restricts the second device from sharing the COT with the first device based at least in part on the sharing information for the COT, wherein the communicating comprises:

receiving a sidelink data message from the second device within the COT based at least in part on the sidelink control message.
The method of claim 49, wherein:

the sidelink control message comprises a hop counter indicating a number of devices sharing the COT, the method further comprising:

comparing the hop counter to a threshold number of hops, wherein the sidelink control message is determined to restrict the second device from sharing the COT with the first device based at least in part on the hop counter corresponding to the threshold number of hops.
The method of claim 49, further comprising:

identifying a threshold distance supporting sharing of the COT;

determining a distance between a source node for sharing the COT and the first device; and

comparing the determined distance to the threshold distance, wherein the sidelink control message is determined to restrict the second device from sharing the COT with the first device based at least in part on the comparing the determined distance to the threshold distance.
The method of claim 49, further comprising:

refraining from transmitting a sidelink message within the COT based at least in part on the sidelink control message restricting the second device from sharing the COT with the first device.
The method of claim 35, further comprising:

receiving a sidelink data message from the second device within the COT based at least in part on the sidelink control message; and

refraining from transmitting a feedback message to the second device within the COT in response to the sidelink data message based at least in part on the second device corresponding to a node subsequent to a source node for sharing the COT.
The method of claim 35, further comprising:

determining a group identifier associated with the sidelink control message, wherein whether the first device is one of the plurality of devices with which the second device shares the COT is determined based at least in part on the group identifier.
The method of claim 54, further comprising:

transmitting a sidelink message within the COT based at least in part on a group of devices corresponding to the group identifier comprising the first device.
The method of claim 55, wherein:

the sidelink message comprises the group identifier.
The method of claim 54, further comprising:

refraining from transmitting a sidelink message within the COT based at least in part on a group of devices corresponding to the group identifier not comprising the first device.
The method of claim 54, wherein:

the sidelink control message comprises the group identifier.
The method of claim 54, further comprising:

determining the group identifier based at least in part on a source node for sharing the COT, a device served by the sidelink control message, or a combination thereof.
The method of claim 54, further comprising:

receiving a radio resource control configuration message indicating the group identifier for the first device, a set of devices corresponding to the group identifier, or a combination thereof.
The method of claim 35, wherein:

the sidelink control message comprises a first stage control message received on a physical sidelink control channel, a second stage control message received on a physical sidelink shared channel, or a combination thereof.
The method of claim 35, wherein:

the first device comprises a first user equipment (UE) , a first access point, a first base station, or a combination thereof; and

the second device comprises a second UE, a second access point, a second base station, or a combination thereof.
A method for wireless communications at a first device, comprising:

gaining access to a communication link for a channel occupancy time (COT) ;

generating a sidelink control message, the sidelink control message comprising sharing information for the COT of the communication link; and

transmitting the sidelink control message to a second device, wherein the sidelink control message indicates whether the second device is one of a plurality of devices with which the first device shares the COT based at least in part on the sharing information.
The method of claim 63, further comprising:

transmitting a sidelink data message to the second device within the COT based at least in part on the sidelink control message; and

receiving a feedback message from the second device within the COT in response to the sidelink data message based at least in part on the sidelink control message supporting the first device sharing the COT with the second device and the first device corresponding to a source node for sharing the COT.
The method of claim 63, wherein:

the sidelink control message comprises a hop counter indicating a number of devices sharing the COT, a bit indicating if the sidelink control message supports sharing of the COT, or a combination thereof; and

whether the second device is one of the plurality of devices with which the first device shares the COT is based at least in part on the hop counter, the bit, or a combination thereof.
The method of claim 63, wherein:

the sidelink control message comprises an indication of the first device as a source node for sharing the COT; and

whether the second device is one of the plurality of devices with which the first device shares the COT is based at least in part on a distance from the source node.
The method of claim 63, wherein:

the sidelink control message comprises a group identifier; and

whether the second device is one of the plurality of devices with which the first device shares the COT is based at least in part on the group identifier.
The method of claim 63, wherein:

the first device comprises a first user equipment (UE) , a first access point, a first base station, or a combination thereof; and

the second device comprises a second UE, a second access point, a second base station, or a combination thereof.
An apparatus for wireless communications at a first device, comprising:

means for receiving a sidelink control message from a second device, the sidelink control message comprising sharing information for a channel occupancy time (COT) of a communication link;

means for determining whether the first device is one of a plurality of devices with which the second device shares the COT based at least in part on the sidelink control message; and

means for communicating over the communication link within the COT based at least in part on the determining.
An apparatus for wireless communications at a first device, comprising:

means for gaining access to a communication link for a channel occupancy time (COT) ;

means for generating a sidelink control message, the sidelink control message comprising sharing information for the COT of the communication link; and

means for transmitting the sidelink control message to a second device, wherein the sidelink control message indicates whether the second device is one of a plurality of devices with which the first device shares the COT based at least in part on the sharing information.
A non-transitory computer-readable medium storing code for wireless communications at a first device, the code comprising instructions executable by a processor to:

receive a sidelink control message from a second device, the sidelink control message comprising sharing information for a channel occupancy time (COT) of a communication link;

determine whether the first device is one of a plurality of devices with which the second device shares the COT based at least in part on the sidelink control message; and

communicate over the communication link within the COT based at least in part on the determining.
A non-transitory computer-readable medium storing code for wireless communications at a first device, the code comprising instructions executable by a processor to:

gain access to a communication link for a channel occupancy time (COT) ;

generate a sidelink control message, the sidelink control message comprising sharing information for the COT of the communication link; and

transmit the sidelink control message to a second device, wherein the sidelink control message indicates whether the second device is one of a plurality of devices with which the first device shares the COT based at least in part on the sharing information.