Patent Description:
Some aspects of wireless communication may comprise direct communication between devices based on sidelink, such as in vehicle-to-everything (V2X) and/or other device-to-device (D2D) communication. There exists a need for further improvements in sidelink technology.

United States Patent Application Publication No. <CIT> relates to a method and apparatus for network controlled resource allocation in NR V2X.

In an aspect of the disclosure, a method, a computer-readable medium, and an apparatus are provided. The apparatus may include a first user equipment (UE) included in a UE group and a second UE outside of the UE group.

The first UE may determine that a sidelink channel is available for data transmission and transmit sidelink control information (SCI) reserving a channel occupancy time (COT) on the sidelink channel in response to determining that the sidelink channel is available for data transmission. The COT may include a first set of resources reserved for the first UE for sidelink data transmission on the sidelink channel, a second set of resources as an intra-group sharable resources capable of being shared by a UE group including the first UE for sidelink transmission on the sidelink channel, and a third set of resources as an inter-group sharable resources capable of being shared by the second UE outside of the UE group for the sidelink transmission on the sidelink channel.

The first UE may determine that the sidelink channel is available for the data transmission based on a listen-before-talk (LBT) procedure. The first UE may determine that the sidelink channel is available for the data transmission by performing a category (CAT) <NUM> LBT procedure.

The inter-group sharable resources may be reserved for sharing with the second UE outside of the UE group. The SCI may indicate the inter-group sharable resources of the COT on the sidelink channel that are capable of being shared by the second UE outside of the UE group.

The inter-group sharable resources may overlap in time with the first set of resources, and the inter-group sharable resources may include resources that do not overlap in time with the first set of resources.

A first UE within the UE group may contend for the intra-group sharable resources based on a first type of LBT procedure and a second UE outside the UE group may contend for the intra-group sharable resources based on a second type of LBT procedure, where the first type of LBT procedure may include a CAT <NUM> or CAT <NUM> LBT procedure and the second type of LBT procedure may include a CAT <NUM> LBT procedure.

The SCI may indicate the first set of resources and the intra-group sharable resources of the COT on the sidelink channel, where the inter-group sharable resources may include remaining resources of the COT. The SCI may indicate a priority threshold value for use of the inter-group sharable resources by the second UE outside of the UE group. The SCI may indicate a packet delay budget (PDB) threshold value for use of the inter-group sharable resources by the second UE outside of the UE group. The SCI may include a group identifier (ID) identifying the UE group. The SCI may include a field that may indicate whether inter-group sharing is allowed. The SCI may include a list of one or more group IDs for additional UE groups for inter-group sharing of the inter-group sharable resources.

The first UE may monitor for sidelink transmissions in the intra-group sharable resources of the COT, compute a usage ratio of resources of the intra-group sharable resources reserved for the UE group on the sidelink channel, and adjust a size of the intra-group sharable resources in an additional COT based on the usage ratio. The size of the intra-group sharable resources may be adjusted by increasing the size of the intra-group sharable resources in response to the computed usage ratio being greater than or equal to a usage threshold value, or decreasing the size of the intra-group sharable resources in response to the computed usage ratio being smaller than a usage threshold value.

The second UE may receive, from the first UE, the SCI reserving the COT on the sidelink channel, the COT including the intra-group sharable resources capable of being shared by the UE group that includes the first UE and does not include the second UE, and the inter-group sharable resources capable of being shared by the UE outside of the UE group for sidelink transmissions on the sidelink channel, and transmitting a sidelink transmission on the sidelink channel using one or more resources of the inter-group sharable resources.

The second UE may perform an LBT procedure before transmitting the sidelink transmission on the sidelink channel using the one or more resources of the intra-group sharable resources or the inter-group sharable resources. The second UE may contend for the intra-group sharable resources based on a different type of LBT procedure than the UE group uses to contend for the intra-group sharable resources. The second UE may also contend for the inter-group sharable resources based on the same type of LBT procedure as the UE group uses to contend for the intra-group sharable resources.

When the SCI indicates a priority threshold value, the second UE may transmit the sidelink transmission on the sidelink channel using the one or more resources of the inter-group sharable resources based on a priority of the sidelink transmission meeting the priority threshold value. When the SCI indicates a PDB threshold value, the second UE may transmit the sidelink transmission on the sidelink channel using the one or more resources of the inter-group sharable resources based on a PDB at the second UE meeting the PDB threshold value. When the SCI includes a list of one or more group IDs for additional UE groups for inter-group sharing of the inter-group sharable resources, the second UE may transmit the sidelink transmission on the sidelink channel using the one or more resources of the inter-group sharable resources based on the second UE being a part of one of the additional UE groups.

A link between a UE <NUM> and a base station <NUM> or <NUM> may be established as an access link, e.g., using a Uu interface. Other communication may be exchanged between wireless devices based on sidelink. For example, some UEs <NUM> may communicate with each other directly using a device-to-device (D2D) communication link <NUM>. In some examples, the D2D communication link <NUM> may use the DL/UL WWAN spectrum.

Some examples of sidelink communication may include vehicle-based communication devices that can communicate from vehicle-to-vehicle (V2V), vehicle-to-infrastructure (V2I) (e.g., from the vehicle-based communication device to road infrastructure nodes such as a Road Side Unit (RSU)), vehicle-to-network (V2N) (e.g., from the vehicle-based communication device to one or more network nodes, such as abase station), vehicle-to-pedestrian (V2P), cellular vehicle-to-everything (C-V2X), and/or a combination thereof and/or with other devices, which can be collectively referred to as vehicle-to-anything (V2X) communications. Sidelink communication may be based on V2X or other D2D communication, such as Proximity Services (ProSe), etc. In addition to UEs, sidelink communication may also be transmitted and received by other transmitting and receiving devices, such as Road Side Unit (RSU) <NUM>, etc. Sidelink communication may be exchanged using a PC5 interface, such as described in connection with the example in <FIG>. Although the following description, including the example slot structure of <FIG>, may provide examples for sidelink communication in connection with <NUM> NR, the concepts described herein may be applicable to other similar areas, such as LTE, LTE-A, CDMA, GSM, and other wireless technologies.

Referring again to <FIG>, in certain aspects, a UE <NUM> in a UE group, or other device communicating based on sidelink, may include a group resource sharing component <NUM> configured to determine that a sidelink channel is available for data transmission and transmit SCI reserving a COT on the sidelink channel in response to determining that the sidelink channel is available for data transmission. Referring again to <FIG>, in certain aspects, a UE <NUM> outside the UE group, or other device communicating based on sidelink, may include an inter-group resource sharing component <NUM> configured to may receive, from the first UE, SCI reserving a COT on a sidelink channel, and transmitting a sidelink transmission on the sidelink channel using one or more resources of the inter-group sharable resources. The COT may include a first set of resources reserved for the first UE for sidelink data transmission on the sidelink channel, a second set of resources as an intra-group sharable resources capable of being shared by the UE group including the first UE for sidelink transmission on the sidelink channel, and a third set of resources as an inter-group sharable resources capable of being shared by the second UE outside of the UE group for the sidelink transmission on the sidelink channel. Although the following description may be focused on <NUM> NR and NR-U sidelink, the concepts described herein may be applicable to other similar areas, such as WiFi <NUM>, LTE, LTE-A, CDMA, GSM, and other wireless technologies.

The communication links <NUM> between the base stations <NUM> and the UEs <NUM> may include uplink (UL) (also referred to as reverse link) transmissions from a UE <NUM> to a base station <NUM> and/or downlink (DL) (also referredto as forward link) transmissions from a base station <NUM> to a UE <NUM>. The communication links <NUM> may use multiple-in put and multiple-output (MIMO) antenna technology, including spatial multiplexing, beamforming, and/or transmit diversity. Allocation of carriers may be asymmetric with respectto DL and UL (e.g., more or fewer carriers may be allocated for DL than for UL).

The frequencies between FR1 and FR2 are often referredto as mid-band frequencies.

Similarly, beamforming may be applied for sidelink communication, e.g., between UEs.

Although this example is described for the base station <NUM> and UE <NUM>, the aspects may be similarly applied between a first and second device (e.g., a first and second UE) for sidelink communication.

The UE <NUM> may also be referredto as a station, a mobile station, a subscriber station, a mobile unit, a subscriber unit, a wireless unit, a remote unit, a mobile device, a wireless device, a wireless communications device, a remote device, a mobile subscriber station, an access terminal, a mobile terminal, a wireless terminal, a remote terminal, a handset, a user agent, a mobile client, a client, or some other suitable terminology.

<FIG> includes diagrams <NUM> and <NUM> illustrating example aspects of slot structures that may be used for sidelink communication (e.g., between UEs <NUM>, RSU <NUM>, etc.). The slot structure may be within a <NUM>/NR frame structure in some examples. In other examples, the slot structure may be within an LTE frame structure. The example slot structure in <FIG> is merely one example, and other sidelink communication may have a different frame structure and/or different channels for sidelink communication. Diagram <NUM> illustrates a single resource block of a single slot transmission, e.g., which may correspond to a <NUM> transmission time interval (TTI). A physical sidelink control channel may be configured to occupy multiple physical resource blocks (PRBs), e.g., <NUM>, <NUM>, <NUM>, <NUM>, or <NUM> PRBs. The PSCCH may be limited to a single sub-channel. A PSCCH duration may be configured to be <NUM> symbols or <NUM> symbols, for example. A sub-channel may comprise <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, or <NUM> PRBs, for example. The resources for a sidelink transmission may be selected from a resource pool including one or more subchannels. As a non-limiting example, the resource pool may include between <NUM>-<NUM> subchannels. A PSCCH size may be established for a resource pool, e.g., as between <NUM>-<NUM> % of one subchannel for a duration of <NUM> symbols or <NUM> symbols. The diagram <NUM> in <FIG> illustrates an example in which the PSCCH occupies about <NUM>% of a subchannel, as one example to illustrate the concept of PSCCH occupying a portion of a subchannel. The physical sidelink shared channel (PSSCH) occupies at least one subchannel. The PSCCH may include a first portion of sidelink control information (SCI), and the PSSCH may include a second portion of SCI in some examples.

Each time slot may include a resource block (RB) (also referred to as physical RBs (PRBs)) that extends <NUM> consecutive subcarriers. As illustrated in <FIG>, some of the REs may comprise control information in PSCCH and some Res may comprise demodulation RS (DMRS). At least one symbol may be used for feedback. <FIG> illustrates examples with two symbols for a physical sidelink feedback channel (PSFCH) with adjacent gap symbols. A symbol prior to and/or after the feedback may be used for turnaround between reception of data and transmission of the feedback. The gap enables a device to switch from operating as a transmitting device to prepare to operate as a receiving device, e.g., in the following slot. Data may be transmitted in the remaining REs, as illustrated. The data may comprise the data message described herein. The position of any of the data, DMRS, SCI, feedback, gap symbols, and/or LBT symbols may be different than the example illustrated in <FIG>. Multiple slots may be aggregated together in some examples.

<FIG> is a block diagram <NUM> of a first wireless communication device <NUM> in communication with a second wireless communication device <NUM> based on sidelink. In some examples, the devices <NUM> and <NUM> may communicate based on V2X or other D2D communication. The communication may be based on sidelink using a PC5 interface. The devices <NUM> and <NUM> may comprise a UE, an RSU, a base station, etc. Packets may be provided to a controller/processor <NUM> that implements layer <NUM> and layer <NUM> functionality.

Similar to the functionality described in connection with the transmission by device <NUM>, the controller/processor <NUM> may provide RRC layer functionality associated with system information (e.g., MIB, SIBs) acquisition, RRC connections, and measurement reporting; PDCP layer functionality associated with header compression/decompression, and security (ciphering, deciphering, integrity protection, integrity verification); RLC layer functionality associated with the transfer of upper layer PDUs, error correction through ARQ, concatenation, segmentation, and reassembly of RLC SDUs, re-segmentation of RLC data PDUs, and reordering of RLC data PDUs; and MAC layer functionality associated with mapping between logical channels and transport channels, multiplexing of MAC SDUs onto TBs, demultiplexing of MAC SDUs from TBs, scheduling information reporting, error correction through HARQ, priority handling, and logical channel prioritization.

At least one of the TX processor <NUM>, the RX processor <NUM>, and the controller/processor <NUM> may be configured to perform aspects in connection with the group resource sharing component <NUM> of <FIG>. At least one of the TX processor <NUM>, the RX processor <NUM>, and the controller/processor <NUM> may be configured to perform aspects in connection the inter-group resource sharing component <NUM> of <FIG>.

<FIG> illustrates an example <NUM> of wireless communication between devices based on sidelink communication. The communication may be based on a slot structure comprising aspects described in connection with <FIG>. For example, transmitting UE <NUM> may transmit a transmission <NUM>, e.g., comprising a control channel and/or a corresponding data channel, that may be received by receiving UEs <NUM>, <NUM>, <NUM>. A control channel may include information for decoding a data channel and may also be used by receiving device to avoid interference by refraining from transmitting on the occupied resources during a data transmission. The number of TTIs, as well as the RBs that will be occupied by the data transmission, may be indicated in a control message from the transmitting device. The UEs <NUM>, <NUM>, <NUM>, <NUM> may each be capable of operating as a transmitting device in addition to operating as a receiving device. Thus, UEs <NUM>, <NUM> are illustrated as transmitting transmissions <NUM>, <NUM>. The transmissions <NUM>, <NUM>, <NUM> may be broadcast or multicast to nearby devices. For example, UE <NUM> may transmit communication intended for receipt by other UEs within a range <NUM> of UE <NUM>. Additionally/alternatively, RSU <NUM> may receive communication from and/or transmit the communication <NUM> to UEs <NUM>, <NUM>, <NUM>, <NUM>.

In some aspects, the sidelink communication may include congestion control algorithms to avoid congestion among various devices and to assist in sharing of resources between the devices. A plurality of sidelink UEs may compete with one another to use the limited amount of time/frequency resources to communicate transmissions. In some examples, sidelink devices may contend with other technologies in order to use wireless resources in the unlicensed spectrum. As an example of a type of sidelink transmissions, eMBB traffic may be transmitted between UEs via NR-U sidelink. Congestion control for sidelink may not provide adequate network performance in case of heavy-loaded or bursty traffic.

In a contention-based sidelink communication, every UE configured to communicate on a sidelink channel may contend for a channel occupancy time (COT) to communicate data transmission. In response to a UE successfully securing the COT to communicate the data transmission, the UE may transmit SCI indicating the time/frequency resources allocated for data transmission by the UE. The UE may communicate the data transmission on the allocated time/frequency resources.

For example, one or more UEs configured to communicate on the sidelink channel may perform a listen-before-talk (LBT) procedure to contend for the COT to communicate data transmission. That is, each sidelink UE with data to transmit on a sidelink channel may perform a clear channel assessment (CCA) procedure to determine whether a channel measurement of the received power is greater than a threshold value in order to determine whether the channel is available for data transmission by the UE. A UE may determine that channel is available if the channel measurement of the received power is lower than a threshold value, and the UE may determine that the sidelink channel is not available for data transmission if the channel measurement is higher than the threshold.

The LBT performed by the plurality of UEs configured to communicate on the sidelink channel may have different categories or types of procedures. For example, a CAT <NUM> LBT may refer to no LBT, a CAT <NUM> LBT may refer to an LBT without random backoff, a CAT <NUM> LBT may refer to an LBT with a random backoff with a fixed-size contention window, and a CAT <NUM> LBT may refer to an LBT with the random backoff with variable size contention window. The CAT <NUM> LBT or the CAT <NUM> LBT may be defined with the random backoff with the contention window to provide less probability of collision with other data transmission. The CAT <NUM> or CAT <NUM> LBT may have a better chance to secure the COT and communicate the data transmission, but the UEs may be configured to contend for the COT with the CAT <NUM> or CAT <NUM> LBT to reduce the collision of data transmission.

In a dense deployment of sidelink UEs, a heavy collision may occur when all the UEs try to access the shared time/frequency resources. Under the heavy collision, the existing congestion algorithm may collapse and cause long delays and a larger packet error rate (PER).

In some aspects, the sidelink UE may communicate with a limited number of UEs within a particular group of UEs. In one example, a user may be playing an online game with a couple of UEs. In another example, in an industrial application, a group of sensors/actuators controlled by the same programmable logic controller (PLC) may be exclusively communicating within the same group of sensors/actuators. In the case where the limited number of UEs are communicating within the particular group of UEs, the group of sidelink UEs may be configured to share the group time/frequency resources to alleviate the collision problem.

In some aspects, a group of sidelink UEs may be configured to share the group time/frequency resources within the group of sidelink UEs. During the channel contention phase, the plurality of sidelink UEs may individually contend to secure the COT. A first UE group may include a first UE, and the first UE may individually contend to secure the COT. In response to securing the COT, the first UE may share the COT with the other UEs within the first UE group. The first UE may transmit the SCI to indicate the group COT and the UEs that may share the group COT. The UEs included in the UE group and UEs addressed by the SCI may share the group COT and may use at least a portion of the group COT for a sidelink transmission.

A plurality of UEs within the same group may be configured with the same group index to indicate that the plurality of UEs belongs to the same group. The plurality of UEs may configure the group indices indicating in which group each UE is included. The group index may be configured through RRC messages. The SCI may include an explicit group ID to identify the UEs that may share the group COT. The UE that may share the group COT may forward group information to configure the UE group. In other examples, a different UE or device may have configured the UE group. The sidelink UE may be configured with a list of group UE IDs in its UE group. When a UE receives an SCI, the UE may compare the group UE ID list of the UE with the source/destination ID to the group ID list to determine if the received SCI is for the UEs in the same UE group. The UE may determine whether to share the COT based on whether the received SCI is for the UEs in the same UE group.

The group configuration may be decided on an application level. For example, the group configuration may include the UEs within a service group or associated with a service that belongs to a particular operator and/or owner.

<FIG> illustrates an example <NUM> of wireless communication showing COTs shared among different groups of UEs. Example <NUM> may include four (<NUM>) super-groups, including group <NUM><NUM>, group <NUM><NUM>, group <NUM><NUM>, and group <NUM><NUM>, and a smaller group; group <NUM><NUM>. Each super-group may include a large number of UEs, e.g., <NUM> UEs, and group <NUM><NUM> may have a smaller number of UEs, e.g., <NUM> UEs, compared to the super-groups. Since the UEs within the groups individually contend for the COT, the groups with more UEs are more likely to clear the CAT <NUM> LBT and to have access to a COT. The larger groups may then share the group COT with the UEs within their respective groups. As the super-groups have a large number of UEs, the super-groups may have a better chance of clearing the LBT to secure the group COT. The smaller group with fewer UEs is less likely to secure the group COT. Thus, as illustrated in <FIG>, group <NUM><NUM> may secure and share COT <NUM>, group <NUM><NUM> may secure and share COT <NUM>, group <NUM><NUM> may secure and share COT <NUM>, and group <NUM><NUM> may secure and share COT <NUM>. The smaller group of UEs in group <NUM><NUM> may continue to be unsuccessful in clearing CCA as they contend with larger groups of UEs. That may leave group <NUM><NUM> without access to wireless resources in an ongoing manner. For example, groups <NUM>-<NUM> may time-division multiplex (TDM) their group COTs in a back-to-back manner without providing an opportunity for group <NUM><NUM> to access the medium until the UEs in groups <NUM>-<NUM> have finished their transmissions. The delay for the UEs of group <NUM><NUM> to access the medium in order to transmit sidelink transmissions may create an unacceptable delay for the sidelink communication. As well, the length of a COT secured by one of groups <NUM>-<NUM> may further impact time-sensitive packets from the UEs in group <NUM><NUM>.

Referring to example <NUM>, the group <NUM><NUM>, the group <NUM><NUM>, the group <NUM><NUM>, and the group <NUM><NUM> may secure the COTs consecutively back to back. That is, one of the UEs of the group <NUM><NUM> may first clear the CAT <NUM> LBT and share COT <NUM> for the UEs within the group <NUM><NUM>. The UEs within the group <NUM><NUM> may contend for the time/frequency resource within the group <NUM><NUM> with CAT <NUM> or CAT <NUM> LBT. After the COT <NUM>, one of the UEs of the group <NUM><NUM> may clear the CAT <NUM> LBT and share COT <NUM> for the UEs within the group <NUM><NUM>. The UEs within the group <NUM><NUM> may contend for the time/frequency resource within the group <NUM><NUM> with CAT <NUM> or CAT <NUM> LBT. After the COT <NUM>, one of the UEs of the group <NUM><NUM> may clear the CAT <NUM> LBT and share COT <NUM> for the UEs of the group <NUM><NUM>. The UEs within the group <NUM><NUM> may contend for the time/frequency resource within the group <NUM><NUM> with CAT <NUM> or CAT <NUM> LBT. After the COT <NUM>, one of the UEs of the group <NUM><NUM> may first clear the CAT <NUM> LBT and share COT <NUM> for the UEs of the group <NUM><NUM>. The UEs within the group <NUM><NUM> may contend for the time/frequency resource within the group <NUM><NUM> with CAT <NUM> or CAT <NUM> LBT. The group <NUM><NUM> with a smaller number of UE may need to wait for the group <NUM>~<NUM> to finish their transmission before the group <NUM><NUM> may clear the CAT <NUM> LBT to secure the COT <NUM>. In other examples, the UEs in group <NUM><NUM> may continue to be unsuccessful in accessing resources for sidelink transmission. However, this may not cause an unacceptable delay for the time-sensitive data or control signaling for the group <NUM><NUM>.

In some aspects, the group COT may be configured for a long time period, e.g., <NUM>, and the group COT may be configured to include reserved resources and let the UEs outside the UE group to contend for the reserved resources using LBT of a different category. That is, the group COT may be configured to include the reserved resources, the UEs within the UE group may contend for the reserved resources using the CAT <NUM> or CAT <NUM> LBT, and UEs outside the UE group may contend for the reserved resources using the CAT <NUM> LBT. Accordingly, the UEs of other groups may not be able to deliver the time-sensitive packets with CAT <NUM> LBT within the UE group, and rely on the CAT <NUM> LBT and contend with CAT <NUM> LBT in the group COT. Aspects presented herein enable the group COT sharing scheme to further allow other UEs from outside of a group to share at least a portion of the resources of the group COT.

In some aspects, an inter-group COT sharing may be introduced to address the low latency signaling/traffic. The SCI may include new COT-SI signaling fields to enable the inter-group COT sharing.

<FIG> illustrates example time/frequency resource structure <NUM> of wireless communication. The example time/frequency resource structure <NUM> illustrates the shared COT <NUM> cleared by a first UE (UE<NUM>) for a first UE group, including UE<NUM>, a second UE (UE<NUM>), and the third UE (UE<NUM>). The example time/frequency resource structure <NUM> may include UE<NUM> transmission resources <NUM> and first intra-group sharable resources <NUM>.

UE<NUM> may clear the CAT <NUM> LBT for the first UE group and secure the COT for the first UE group. The UE<NUM> may determine the UE<NUM> transmission resources <NUM> to communicate the data transmission and configure the UE<NUM> transmission resources <NUM> and the reserved resources <NUM>. UE<NUM> may use subchannel #<NUM> in the used COT sharing region to communicate the UE<NUM> transmission and configure subchannel #<NUM><NUM> and subchannel #<NUM><NUM> in the used COT as second intra-group sharable resources <NUM> reserved for the UEs of the first UE group. UE<NUM> may transmit the SCI <NUM>, indicating the configuration of the shared COT <NUM>. UE<NUM> and UE<NUM> of the first UE group may receive the SCI <NUM> and determine to communicate data transmission within the used COT sharing region. UE<NUM> and UE<NUM> may contend for the time/frequency resources using the CAT <NUM> or CAT <NUM> LBT. In one aspect, under the CAT <NUM> LBT, the SCI <NUM> may allocate the UE<NUM> transmission and the UE<NUM> transmission for the UE<NUM> and the UE<NUM>. In one aspect, UE<NUM> may contend for the time/frequency resources using the CAT <NUM> LBT and secure UE<NUM> transmission resources <NUM> for the UE<NUM> data transmission within the second intra-group sharable resources <NUM>. UE<NUM> may contend for the time/frequency resource using the CAT <NUM> LBT and secure UE<NUM> transmission resources <NUM> for the UE<NUM> data transmission within the second intra-group sharable resources <NUM>.

The UEs of the first UE group may clear the CAT <NUM> LBT to allocate at least a part of the first intra-group sharable resources <NUM> and the second intra-group sharable resources <NUM> to communicate data transmission on the sidelink channel. The UEs outside the first UE group may not access the first intra-group sharable resources <NUM> and the second intra-group sharable resources <NUM> of the UE<NUM> COT using the CAT <NUM> or CAT <NUM> LBT. The UEs outside the first UE group may attempt to access the first intra-group sharable resources <NUM> of the UE<NUM> COT and communicate data transmission with the CAT <NUM> LBT. The initiating UE, which is the UE<NUM>, may maintain a contiguous transmission with an optional gap of <NUM> microseconds (µs), and the UEs outside the first UE group may have little chance to clear the CAT <NUM> if being close to the UE<NUM>. Within the intra-group sharable resources <NUM> of the remaining COT region, the UEs in the first UE group may leave a gap, e.g., one (<NUM>) empty slot. Accordingly, the UEs outside the first UE group may still have a chance to access the COT with CAT <NUM> LBT in the intra-group sharable resources.

However, in the heavily loaded case, the UEs within the first UE group may TDM back-to-back in the remaining COT. The UEs outside the first UE group may not easily clear the CAT4 LBT. Also, if the used COT sharing region is long, e.g., <NUM>, in comparison to time-sensitive data (e.g., associated with a time that is less than <NUM>), the UEs outside of the first group may not be able to access wireless resources to transmit the time-sensitive traffic within the time window for the time-sensitive data.

The COT initiating UE may reserve resources to be used by UEs outside the shared UE group. The COT initiating UE may indicate a set of the resource aside from the non-sharable resources and group sharable resources for out-of-group UE to join. That is, UE<NUM> may configure the inter-group sharable resources <NUM>. Referring to the example time/frequency resource structure <NUM>, the UE<NUM> may configure the inter-group sharable resources <NUM> in subchannel #<NUM>. The inter-group sharable resources <NUM> may overlap in time with the used COT region and the remaining COT region. The UEs outside the shared group may contend for the resources in the inter-group sharable resources with the same type of LBT as the UEs within the shared group. For example, UEs outside the shared group may contend for the resources in the inter-group sharable resources with the CAT <NUM> or CAT <NUM> LBT.

In some aspects, The size of the inter-group sharable resources <NUM> may be configured to accommodate the high priority and/or time-sensitive data transmissions for the UEs outside the shared UE group. As any UE may access the inter-group sharable resources, a heavy collision may occur in the inter-group sharable resources for the out-of-group UEs. UE0 may configure some access control to reduce the heavy collision of data transmissions.

In some aspects, the out-of-group UEs may join the COT on the inter-group sharable resources <NUM> for out-of-group UE if the priority is higher than a threshold priority value or the remaining packet delay budget (PDB) is less than a threshold PDB value. The threshold priority value and the threshold PDB value may be preconfigured. The UE<NUM> may configure the threshold priority value and the threshold PDB value. The SCI transmitted by the UE<NUM> may indicate the threshold priority value and the threshold PDB value. Some high priority traffic and the packet running out of PDB may make use of the inter-group sharable resources despite not being in the shared UE group. The restriction on traffic priority and PDB constraint may limit or reduce the collision problem.

In some aspects, COT sharing information (SI) (COT-SI) may include thresholds for the UEs outside the shared UE group. The SCI of the UE<NUM> may include the COT-SI to the SCI. The COT-SI may include the group ID of the shared UE group, and the UEs having the same group ID as specified in COT-SI may use the reserved shared COT resources in the Time/frequency resource grids of the first intra-group sharable resources <NUM> and the second intra-group sharable resources <NUM> for the in-the-group UEs in the used COT sharing region and remaining COT region. The COT-SI may also include an On/Off field to allow inter-group sharing. That is, the On/Off field may indicate whether to include the inter-group sharable resources <NUM>.

The COT-SI may include a list of group IDs for inter-group sharing to limit the inter-group sharing to specific groups. That is, the UE<NUM> may determine to limit the access to the inter-group sharable resources <NUM> to a list of specific groups, and the COT-SI may include the list of group IDs of the specific groups allowed to access the inter-group sharable resources <NUM>.

The COT-SI may indicate the time/frequency resource grid of the inter-group sharable resources <NUM> for the rest of UEs outside the shared UE group and/or the specific groups indicated in the COT-SI.

Priority threshold or PDB threshold for the UE from other/indicated group to join the COT. The out-of-group UEs may access the inter-group sharable resources <NUM> if the packet is above certain priority threshold or the PDB is almost running out. That is, the UE outside the first UE group may receive the COT-SI in the SCI transmitted by the UE<NUM> indicating the threshold priority value and the threshold PDB value, and determine to contend for the inter-group sharable resources to communicate the data transmissions having a priority greater than the threshold priority value and/or a remaining PDB less than the threshold PDB value.

In some aspects, the size of the inter-group sharable resources <NUM> may be adjusted based on the usage of the channel to reduce the time-frequency cost to the intra-group sharable resources. Accordingly, the inter-group sharable resources <NUM> may be scaled up/down based on the usage of the channel. While a group UE is in the RX mode in the shared COT, it may actively listen for the SCI in the sharable resources. The group UE may determine whether the sharable resources are used by UEs from the same group based on the group ID of the SCI. That is, the UEs of the UE group may track whether the sharable resources in the channel are used by the UEs in the shared UE group. The UE may compute the usage ratio on the sharable time/frequency resources and determine whether to scale up/down the inter-group sharable resources. In some aspects, the inter-group sharable resources may be scaled up for the next acquired group COT in response to the usage ratio being above a certain threshold value. The inter-group sharable resources may be scaled down for the next acquired group COT if the usage ratio is below the certain threshold value.

<FIG> illustrates a call-flow diagram <NUM> of a method of wireless communication. The call-flow diagram <NUM> may include a first UE <NUM> within a UE group, and a second UE <NUM> outside the UE group.

At <NUM>, the first UE <NUM> may determine that a sidelink channel is available for data transmission. The first UE <NUM> may determine that the sidelink channel is available for the data transmission based on an LBT procedure. In one aspect, the first UE <NUM> may determine that the sidelink channel is available for the data transmission by performing a CAT <NUM> LBT procedure.

At <NUM>, the first UE <NUM> may transmit SCI reserving a COT on the sidelink channel in response to determining that the sidelink channel is available for data transmission, and the second UE <NUM> may receive, from the first UE <NUM>, the SCI reserving a COT on a sidelink channel.

The COT may include a first set of resources reserved for the first UE <NUM> for sidelink data transmission on the sidelink channel, a second set of resources as an intra-group sharable resources capable of being shared by the UE group including the first UE <NUM> for sidelink transmission on the sidelink channel, and a third set of resources as an inter-group sharable resources capable of being shared by one or more UEs outside of the UE group for the sidelink transmission on the sidelink channel.

The intra-group sharable resources may be shared by the UE group including the first UE <NUM>. The UE group may contend for the intra-group sharable resources based on a first type of LBT procedure. The first type of LBT procedure may include a CAT <NUM> or CAT <NUM> LBT procedure. The one or more UEs outside of the UE group may contend for the intra-group sharable resources based on a second type of LBT procedure. The second type of LBT procedure may include a CAT <NUM> LBT procedure.

The inter-group sharable resources are reserved for sharing with the one or more UEs outside of the UE group. In one aspect, the SCI may indicate the inter-group sharable resources of the COT on the sidelink channel that are capable of being shared by the one or more UEs outside of the UE group. In another aspect, the SCI may indicate the first set of resources and the intra-group sharable resources of the COT on the sidelink channel, and the inter-group sharable resources may include the remaining resources of the COT. The inter-group sharable resources may overlap in time with the first set of resources, and at least a part of the inter-group sharable resources may not overlap in time with the first set of resources.

The SCI may indicate a priority threshold value for use of the inter-group sharable resources by the one or more UEs outside of the UE group. The SCI may indicate a PDB threshold value for use of the inter-group sharable resources by the one or more UEs outside of the UE group. The SCI may include a group ID identifying the UE group. The SCI may include a field that indicates whether inter-group sharing is allowed. The SCI may include a list of one or more group IDs for additional UE groups for inter-group sharing of the third set of resources.

At <NUM>, the second UE <NUM> may perform the LBT procedure before transmitting the sidelink transmission on the sidelink channel using the one or more resources of the intra-group sharable resources or the inter-group sharable resources.

At <NUM>, the second UE <NUM> may transmit a sidelink transmission on the sidelink channel using one or more resources of the inter-group sharable resources. The second UE <NUM> may transmit the sidelink transmission on the sidelink channel using the one or more resources of the inter-group sharable resources based on a priority of the sidelink transmission meeting the priority threshold value indicated in the SCI received at <NUM>. The second UE <NUM> may transmit the sidelink transmission on the sidelink channel using the one or more resources of the inter-group sharable resources based on a PDB at the first UE <NUM> meeting the PDB threshold value indicated in the SCI received at <NUM>. The second UE <NUM> may transmit the sidelink transmission on the sidelink channel using the one or more resources of the inter-group sharable resources based on the second UE <NUM> being a part of the additional UE groups for inter-group sharing indicated in the SCI received at <NUM>.

At <NUM>, the first UE <NUM> may monitor for sidelink transmissions in the intra-group sharable resources of the COT. At <NUM>, the first UE <NUM> may compute a usage ratio of resources of the intra-group sharable resources reserved for the UE group on the sidelink channel.

At <NUM>, the first UE <NUM> may adjust a size of the intra-group sharable resources in an additional COT based on the usage ratio. The first UE <NUM> may increase the size of the intra-group sharable resources in response to the computed usage ratio being greater than or equal to a usage threshold value. The first UE <NUM> may decrease the size of the intra-group sharable resources in response to the computed usage ratio being smaller than a usage threshold value.

<FIG> is a flowchart <NUM> of a method of wireless communication. The method may be performed by a UE included in a UE group (e.g., the UE <NUM>; the first UE <NUM>; the apparatus <NUM>).

At <NUM>, the UE may be configured to determine that a sidelink channel is available for data transmission (i.e., as at <NUM>). The UE may determine that the sidelink channel is available for the data transmission based on an LBT procedure. In one aspect, the UE may determine that the sidelink channel is available for the data transmission by performing a CAT <NUM> LBT procedure. For example, <NUM> may be performed by an LBT component <NUM>.

At <NUM>, the UE may be configured to transmit SCI reserving a COT on the sidelink channel in response to determining that the sidelink channel is available for data transmission (i.e., as at <NUM>). The COT may include a first set of resources reserved for the UE for sidelink data transmission on the sidelink channel, a second set of resources as an intra-group sharable resources capable of being shared by the UE group including the UE for sidelink transmission on the sidelink channel, and a third set of resources as an inter-group sharable resources capable of being shared by one or more UEs outside of the UE group for the sidelink transmission on the sidelink channel. The intra-group sharable resources may be shared by the UE group including the UE. The UE group may contend for the intra-group sharable resources based on a first type of LBT procedure. The first type of LBT procedure may include a CAT <NUM> or CAT <NUM> LBT procedure. The one or more UEs outside of the UE group may contend for the intra-group sharable resources based on a second type of LBT procedure. The second type of LBT procedure may include a CAT <NUM> LBT procedure. The inter-group sharable resources may be reserved for sharing with the one or more UEs outside of the UE group. The one or more UEs outside of the UE group may contend for the inter-group sharable resources based on the first type of LBT procedure including the CAT <NUM> or CAT <NUM> LBT procedure. In one aspect, the SCI may indicate the inter-group sharable resources of the COT on the sidelink channel that may be capable of being shared by the one or more UEs outside of the UE group. In another aspect, the SCI may indicate the first set of resources and the intra-group sharable resources of the COT on the sidelink channel, and the inter-group sharable resources may include the remaining resources of the COT. The inter-group sharable resources may overlap in time with the first set of resources, and at least a part of the inter-group sharable resources may not overlap in time with the first set of resources. The SCI may indicate a priority threshold value for use of the inter-group sharable resources by the one or more UEs outside of the UE group. The SCI may indicate a PDB threshold value for use of the inter-group sharable resources by the one or more UEs outside of the UE group. The SCI may include a group ID identifying the UE group. The SCI may include a field that indicates whether inter-group sharing is allowed. The SCI may include a list of one or more group IDs for additional UE groups for inter-group sharing of the third set of resources. For example, <NUM> may be performed by a group resource sharing component <NUM>.

At <NUM>, the UE may be configured to monitor for sidelink transmissions in the intra-group sharable resources of the COT (i.e., as at <NUM>). For example, <NUM> may be performed by the group resource sharing component <NUM>.

At <NUM>, the UE may be configured to compute a usage ratio of resources of the intra-group sharable resources reserved for the UE group on the sidelink channel (i.e., as at <NUM>). For example, <NUM> may be performed by the group resource sharing component <NUM>.

At <NUM>, the UE may be configured to adjust a size of the intra-group sharable resources in an additional COT based on the usage ratio (i.e., as at <NUM>). The UE may increase the size of the intra-group sharable resources in response to the computed usage ratio being greater than or equal to a usage threshold value. The UE may decrease the size of the intra-group sharable resources in response to the computed usage ratio being smaller than a usage threshold value. For example, <NUM> may be performed by the group resource sharing component <NUM>.

<FIG> is a flowchart <NUM> of a method of wireless communication. The method may be performed by a UE outside a UE group (e.g., the UE <NUM>; the second UE <NUM>; the apparatus <NUM>).

At <NUM>, the UE outside a UE group may be configured to recieve SCI reserving a COT on the sidelink channel from another UE of the UE group (i.e., as at <NUM>). The COT may include a first set of resources as an intra-group sharable resources capable of being shared by the UE group including the UE for sidelink transmission on the sidelink channel, and a second set of resources as an inter-group sharable resources capable of being shared by one or more UEs outside of the UE group for the sidelink transmission on the sidelink channel. The UE outside of the UE group may contend for the intra-group sharable resources based on a second type of LBT procedure including a CAT <NUM> LBT procedure. The inter-group sharable resources may be reserved for sharing with the UE outside of the UE group. The UE outside of the UE group may contend for the inter-group sharable resource based on a first type of LBT procedure including the CAT <NUM> or CAT <NUM> LBT procedure. The SCI may indicate the inter-group sharable resources of the COT on the sidelink channel that may be capable of being shared by the UE outside of the UE group. The inter-group sharable resources may overlap in time with the inter-group sharable resources. The SCI may indicate a priority threshold value for use of the inter-group sharable resources by the one or more UEs outside of the UE group. The SCI may indicate a PDB threshold value for use of the inter-group sharable resources by the one or more UEs outside of the UE group. The SCI may include a group ID identifying the UE group. The SCI may include a field that indicates whether inter-group sharing is allowed. The SCI may include a list of one or more group IDs for additional UE groups for inter-group sharing of the third set of resources. For example, <NUM> may be performed by a group resource sharing component <NUM>.

At <NUM>, the UE may be configured to perform the LBT procedure before transmitting the sidelink transmission on the sidelink channel using the one or more resources of the intra-group sharable resources or the inter-group sharable resources (i.e., as at <NUM>). The UE outside of the UE group may contend for the intra-group sharable resources based on a second type of LBT procedure including the CAT <NUM> LBT procedure. The UE outside of the UE group may contend for the inter-group sharable resource based on a first type of LBT procedure including the CAT <NUM> or CAT <NUM> LBT procedure. For example, <NUM> may be performed by an LBT component <NUM>.

At <NUM>, the UE may be configured to transmit a sidelink transmission on the sidelink channel using one or more resources of the inter-group sharable resources (i.e., as at <NUM>). The UE may transmit the sidelink transmission on the sidelink channel using the one or more resources of the inter-group sharable resources based on a priority of the sidelink transmission meeting the priority threshold value indicated in the SCI received at <NUM>. The UE may transmit the sidelink transmission on the sidelink channel using the one or more resources of the inter-group sharable resources based on a PDB at the first UE meeting the PDB threshold value indicated in the SCI received at <NUM>. The UE may transmit the sidelink transmission on the sidelink channel using the one or more resources of the inter-group sharable resources based on the UE being a part of the additional UE groups for inter-group sharing indicated in the SCI received at <NUM>. For example, <NUM> may be performed by the group resource sharing component <NUM>.

The cellular baseband processor <NUM> may include a computer-readable medium/memory. The computer-readable medium/memory may be non-transitory. The cellular baseband processor <NUM> is responsible for general processing, including the execution of software stored on the computer-readable medium/memory. The computer-readable medium/memory may also be used for storing data that is manipulated by the cellular baseband processor <NUM> when executing software. The components within the communication manager <NUM> may be stored in the computer-readable medium/memory and/or configured as hardware within the cellular baseband processor <NUM>.

The communication manager <NUM> includes a group resource sharing component <NUM> that is configured to transmit and receive SCI reserving a COT on the sidelink channel in response to determining that the sidelink channel is available for data transmission, monitor for sidelink transmissions in the intra-group sharable resources of the COT, compute a usage ratio of resources of the intra-group sharable resources reserved for the UE group on the sidelink channel, adjust a size of the intra-group sharable resources in an additional COT based on the usage ratio, and transmit a sidelink transmission on the sidelink channel using one or more resources of the inter-group sharable resources, e.g., as described in connection with <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, and <NUM>. The communication manager <NUM> further includes an LBT component <NUM> that is configured to determine that a sidelink channel is available for data transmission, and perform the LBT procedure before transmitting the sidelink transmission on the sidelink channel using the one or more resources of the intra-group sharable resources or the inter-group sharable resources, e.g., as described in connection with <NUM> and <NUM>. The <NUM> and <NUM> are configured to communicate with each other.

The apparatus may include additional components that perform each of the blocks of the algorithm in the aforementioned flowcharts of <FIG>, <FIG>, and <FIG>. As such, each block in the aforementioned flowcharts of <FIG>, <FIG>, and <FIG> may be performed by a component and the apparatus may include one or more of those components.

In one configuration, the apparatus <NUM>, and in particular the cellular baseband processor <NUM>, includes means for determining that a sidelink channel is available for data transmission, and means for transmitting SCI reserving a COT on the sidelink channel in response to determining that the sidelink channel is available for data transmission. The apparatus <NUM> includes means for monitoring for sidelink transmissions in the second set of resources of the COT, means for computing a usage ratio of resources of the second set of resources reserved for the UE group on the sidelink channel, and means for adjusting the size of the second set of resources in an additional COT based on the usage ratio, including means for increasing the size of the second set of resources in response to the computed usage ratio being greater than or equal to a usage threshold value and means for decreasing the size of the second set of resources in response to the computed usage ratio being smaller than a usage threshold value. The apparatus <NUM> includes means for receiving, from a second UE, SCI reserving a COT on a sidelink channel, and means for transmitting a sidelink transmission on the sidelink channel using one or more resources of the second set of resources. The apparatus <NUM> includes means for performing an LBT procedure before transmitting the sidelink transmission on the sidelink channel using the one or more resources of the first set of resources or the second set of resources. The aforementioned means may be one or more of the aforementioned components of the apparatus <NUM> configured to perform the functions recited by the aforementioned means. As described supra, the apparatus <NUM> may include the TX Processor <NUM>, the RX Processor <NUM>, and the controller/processor <NUM>.

Referring again to <FIG>, <FIG>, <FIG>, <FIG>, <FIG>, and <FIG>, the wireless communication may include a first UE included in a UE group and a second UE outside of the UE group. The first UE may determine that a sidelink channel is available for data transmission and transmit SCI reserving a COT on the sidelink channel in response to determining that the sidelink channel is available for data transmission. The COT may include a first set of resources reserved for the first UE for sidelink data transmission on the sidelink channel, a second set of resources as an intra-group sharable resources capable of being shared by the UE group including the first UE for sidelink transmission on the sidelink channel, and a third set of resources as an inter-group sharable resources capable of being shared by the second UE outside of the UE group for the sidelink transmission on the sidelink channel.

The first UE may determine that the sidelink channel is available for the data transmission based on an LBT procedure. The first UE may determine that the sidelink channel is available for the data transmission by performing a CAT <NUM> LBT procedure.

The SCI may indicate the first set of resources and the intra-group sharable resources of the COT on the sidelink channel, where the inter-group sharable resources may include remaining resources of the COT. The SCI may indicate a priority threshold value for use of the inter-group sharable resources by the second UE outside of the UE group. The SCI may indicate a PDB threshold value for use of the inter-group sharable resources by the second UE outside of the UE group. The SCI may include a group ID identifying the UE group. The SCI may include a field that may indicate whether inter-group sharing is allowed. The SCI may include a list of one or more group IDs for additional UE groups for inter-group sharing of the inter-group sharable resources.

Claim 1:
A method (<NUM>) of wireless communication for a user equipment, UE, comprising:
determining (<NUM>) that a sidelink channel is available for data transmission; and
transmitting (<NUM>) sidelink control information, SCI, reserving a channel occupancy time, COT, on the sidelink channel in response to determining that the sidelink channel is available for data transmission, the COT comprising:
a first set of resources reserved for the UE for sidelink data transmission on the sidelink channel;
a second set of resources capable of being shared by a UE group including the UE for sidelink transmission on the sidelink channel; and
a third set of resources capable of being shared by one or more UEs outside of the UE group for the sidelink transmission on the sidelink channel.