Classifications

• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04W—WIRELESS COMMUNICATION NETWORKS
  • H04W16/00—Network planning, e.g. coverage or traffic planning tools; Network deployment, e.g. resource partitioning or cells structures
  • H04W16/14—Spectrum sharing arrangements between different networks
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04W—WIRELESS COMMUNICATION NETWORKS
  • H04W72/00—Local resource management
  • H04W72/02—Selection of wireless resources by user or terminal
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04W—WIRELESS COMMUNICATION NETWORKS
  • H04W74/00—Wireless channel access
  • H04W74/08—Non-scheduled access, e.g. ALOHA
  • H04W74/0808—Non-scheduled access, e.g. ALOHA using carrier sensing, e.g. carrier sense multiple access [CSMA]
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04W—WIRELESS COMMUNICATION NETWORKS
  • H04W80/00—Wireless network protocols or protocol adaptations to wireless operation
  • H04W80/02—Data link layer protocols
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04W—WIRELESS COMMUNICATION NETWORKS
  • H04W92/00—Interfaces specially adapted for wireless communication networks
  • H04W92/16—Interfaces between hierarchically similar devices
  • H04W92/18—Interfaces between hierarchically similar devices between terminal devices
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04W—WIRELESS COMMUNICATION NETWORKS
  • H04W76/00—Connection management
  • H04W76/10—Connection setup
  • H04W76/14—Direct-mode setup
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04W—WIRELESS COMMUNICATION NETWORKS
  • H04W76/00—Connection management
  • H04W76/10—Connection setup
  • H04W76/19—Connection re-establishment

Definitions

• the present disclosure relates to wireless transmission, and more particularly to methods and apparatuses for handling a consistent listen before talk (LBT) failure.
• LBT listen before talk
• NRU new radio unlicensed
• NRU new radio unlicensed
• An LBT procedure is performed before each transmission to determine whether the unlicensed band or channel is available. If LBT fails, which means the channel has been occupied, an LBT failure indication is sent to the media access control (MAC) entity from lower layers (e.g. a physical (PHY) layer) . Then the MAC entity may count the number of LBT failure indication from lower layer in a time period, and trigger a consistent LBT failure when the number of LBT failure indication exceeds a threshold (for example, a preconfigured maximum number within the time period) .
• MAC media access control
• SL Sidelink
• D2D Device to Device
• V2V Vehicle to Vehicle
• V2P Vehicle to Passenger
• IoT Internet of Things
• SL transmission which may also be operated on an unlicensed band for public safety or commercial use, is required to perform the similar LBT procedure defined in the NRU as discussed above. However, SL transmission would not be initiated if consistent LBT failure is detected or triggered for a SL-BWP since only one SL-BWP is supported for sidelink.
• trigger a consistent LBT failure for the whole SL-BWP instead of trigger a consistent LBT failure for the whole SL-BWP, trigger a consistent LBT failure for a part of SL-BWP, e.g. an RB set is a possible way forward. So it is desirable to provide solutions for handling a per RB set consistent LBT failure in a SL-U system.
• An embodiment of the present disclosure provides a user equipment (UE) , which includes: a transceiver; and a processor coupled with the transceiver and configured to: detect a consistent LBT failure on a resource block (RB) set of an SL bandwidth part (BWP) ; perform one of the following: triggering a resource selection procedure; triggering a resource pool selection procedure; transmitting a first indication indicating the consistent LBT failure on the RB set; determining the RB set as recovered in response to one or more conditions being fulfilled; or triggering a consistent LBT failure for the SL BWP or declare an SL BWP failure.
• UE user equipment
• the resource selection procedure includes: performing a resource selection procedure for remaining transmission (s) on an RB set with no consistent LBT failure for a one-shot transmission; performing a resource selection procedure for reserved resource (s) on the RB set with no consistent LBT failure for a multi-shot transmission; or performing a resource selection procedure for remaining transmission (s) on the RB set with no consistent LBT failure, wherein the remaining transmission (s) is associated with at least one of: a specific destination, a specific logical channel (LCH) , or an LCH with a specific priority level.
• LCH logical channel
• the resource pool selection procedure includes one of the following: prohibiting selection of a resource pool including the RB set; or selecting the resource pool including the RB set in the case that no other resource pool is available and the resource pool includes other RB sets with no consistent LBT failure.
• the resource pool including the RB set is determined with a lower priority level compared with other resource pool (s) with no consistent LBT failure on any RB set in the other resource pool (s) .
• the RB set in the resource pool is determined with a lower priority level compared with other RB set (s) in the resource pool.
• the first indication includes a media access control control element (MAC CE) or a radio resource control (RRC) signalling.
• MAC CE media access control control element
• RRC radio resource control
• the one or more conditions include: a prohibit timer being expired; an LBT success number associated with the RB set being higher than a first threshold; an LBT failure number associated with the RB set being lower than a second threshold; a result of a channel busy ratio (CBR) measurement on that RB set being lower than a third threshold; a second indication from the BS indicating that the RB set is recovered; a third indication from the BS indicating that at least one of the RB set, a resource pool of the RB set, or the SL BWP is reconfigured.
• CBR channel busy ratio
• the processor in the case that a consistent LBT failure on each RB set of the SL BWP is detected, the processor is further configured to: trigger a consistent LBT failure for the SL BWP; or declare an SL BWP failure.
• the processor is further configured to: transmit a fourth indication indicating the consistent LBT failure for the SL BWP.
• a base station which includes: a transceiver; and a processor coupled with the transceiver and configured to: receive, from a UE, a first indication indicating a consistent LBT failure on a resource block (RB) set of an SL BWP; and perform one of the following: transmitting, to the UE, a second indication indicating that the RB set is recovered, or a third indication indicating that at least one of the RB set, a resource pool of the RB set, or the SL BWP is reconfigured; or receiving, from the UE, a fourth indication indicating a consistent LBT failure on each RB set of the SL BWP; and indicating another SL BWP to the UE.
• BS base station
• the first indication includes a MAC CE or a radio resource control (RRC) signalling.
• RRC radio resource control
• Yet another embodiment of the present disclosure provides a method performed by a UE, which includes: detecting a consistent LBT failure on a resource block (RB) set of an SL BWP; performing one of the following: triggering a resource selection procedure; triggering a resource pool selection procedure; transmitting a first indication indicating the consistent LBT failure on the RB set; determining the RB set as recovered in response to one or more conditions being fulfilled; or triggering a consistent LBT failure for the SL BWP or declare an SL BWP failure.
• a method performed by a UE includes: detecting a consistent LBT failure on a resource block (RB) set of an SL BWP; performing one of the following: triggering a resource selection procedure; triggering a resource pool selection procedure; transmitting a first indication indicating the consistent LBT failure on the RB set; determining the RB set as recovered in response to one or more conditions being fulfilled; or triggering a consistent LBT failure for the SL BWP or declare an SL BWP
• Still another embodiment of the present disclosure provides a method performed by a BS, which includes: receiving, from a UE, a first indication indicating a consistent LBT failure on a resource block (RB) set of an SL BWP; and performing one of the following: transmitting, to the UE, a second indication indicating that the RB set is recovered, or a third indication indicating that at least one of the RB set, a resource pool of the RB set, or the SL BWP is reconfigured; or receiving, from the UE, a fourth indication indicating a consistent LBT failure on each RB set of the SL BWP; and indicating another SL BWP to the UE.
• a BS includes: receiving, from a UE, a first indication indicating a consistent LBT failure on a resource block (RB) set of an SL BWP; and performing one of the following: transmitting, to the UE, a second indication indicating that the RB set is recovered, or a third indication indicating that
• Fig. 1 illustrates a schematic diagram of a wireless communication system according to some embodiments of the present disclosure.
• Fig. 2 illustrates a method performed by a UE for handling a consistent LBT failure according to some embodiments of the present disclosure.
• Fig. 3 illustrates a method performed by a BS for handling a consistent LBT failure according to some embodiments of the present disclosure.
• Fig. 4 illustrates a simplified block diagram of an apparatus according to some embodiments of the present disclosure.
• SL UE User equipment (UE) under NR SL-U scenario may be referred to as SL UE (s) .
• An SL UE which transmits data on sidelink in an unlicensed spectrum may be referred to as a UE for transmitting, a transmitting UE, a transmitting SL UE, a Tx UE, an SL Tx UE, an SL BWP Tx UE, a UE, or the like.
• An SL UE which receives data on sidelink in an unlicensed spectrum may be referred to as a UE for receiving, a receiving UE, a receiving SL UE, an Rx UE, an SL Rx UE, a UE, or the like.
• SL UE may include computing devices, such as desktop computers, laptop computers, personal digital assistants (PDAs) , tablet computers, smart televisions (e.g., televisions connected to the Internet) , set-top boxes, game consoles, security systems (including security cameras) , vehicle on-board computers, network devices (e.g., routers, switches, and modems) , internet of things (IoT) devices, personal computer (PC) , game terminal, extended reality (XR) devices, or the like.
• computing devices such as desktop computers, laptop computers, personal digital assistants (PDAs) , tablet computers, smart televisions (e.g., televisions connected to the Internet) , set-top boxes, game consoles, security systems (including security cameras) , vehicle on-board computers, network devices (e.g., routers, switches, and modems) , internet of things (IoT) devices, personal computer (PC) , game terminal, extended reality (XR) devices, or the like.
• IoT internet of things
• SL UE may include a portable wireless communication device, a smart phone, a cellular telephone, a flip phone, a device having a subscriber identity module, a personal computer, a selective call receiver, or any other device that is capable of sending and receiving communication signals on a wireless network.
• SL UE may include wearable devices, such as smart watches, fitness bands, optical head-mounted displays, or the like.
• SL UE (s) may be referred to as a subscriber unit, a mobile, a mobile station, a user, a terminal, a mobile terminal, a wireless terminal, a fixed terminal, a subscriber station, a user terminal, or a device, or described using other terminology used in the art.
• SL UE (s) may communicate directly with BS (s) via communication signals.
• a BS under NR SL-U scenario may be referred to as a base unit, a base, an access point, an access terminal, a macro cell, a Node-B, an enhanced Node B (eNB) , a gNB, a Home Node-B, a relay node, a device, a remote unit, or by any other terminology used in the art.
• a BS may be distributed over a geographic region.
• a BS is a part of a radio access network that may include one or more controllers communicably coupled to one or more corresponding base stations.
• a BS is generally communicably coupled to one or more packet core networks (PCN) , which may be coupled to other networks, like the packet data network (PDN) (e.g., the Internet) and public switched telephone networks, among other networks.
• PCN packet core networks
• PDN packet data network
• MME mobility management entity
• SGW serving gateway
• PGW packet data network gateway
• a BS may serve a number of SL UEs within a serving area, for example, a cell or a cell sector via a wireless communication link.
• a BS may communicate directly with one or more SL UEs via communication signals.
• a BS may serve SL UEs within a macro cell.
• Sidelink communication between a Tx UE and a receive (Rx) UE under NR SL-U scenario includes groupcast communication, unicast communication, or broadcast communication.
• Fig. 1 illustrates a wireless communication system 100 (e.g., an SL-U communication system) in accordance with some embodiments of the present disclosure.
• a wireless communication system 100 e.g., an SL-U communication system
• the wireless communication system 100 includes a base station (e.g., BS 102) , and some UEs (e.g., UE 101-A, UE 101-B, UE 101-C, and UE 101-D) .
• UE 101-A and UE 101-B are within the coverage of BS 102, and UE 101-C and UE 101-D are outside the coverage of BS 102.
• UE 101-A, UE 101-B, UE 101-C, and UE 101-D may perform sidelink unicast transmission, sidelink groupcast transmission, or sidelink broadcast transmission in an unlicensed spectrum, such as the SL BWP.
• UE 101-A, UE 101-B, UE 101-C, and UE 101-D may be referred to as a SL UE. It is contemplated that, in accordance with some other embodiments of the present disclosure, a SL-U communication system may include more BSs and more or fewer SL UEs.
• SL UEs as shown in Fig. 1 are illustrated in the shape of a cellphone, it is contemplated that a SL communication system may include any type of UE (e.g., a roadmap device, a cell phone, a computer, a laptop, IoT device or other type of device) in accordance with some other embodiments of the present disclosure.
• UE e.g., a roadmap device, a cell phone, a computer, a laptop, IoT device or other type of device
• UE 101-A may function as a Tx UE, and UE 101-B, UE 101-C, and UE 101-D may function as Rx UEs.
• UE 101-A may exchange SL messages with UE 101-B or UE 101-C through a sidelink using, for example, the NR technology or the LTE technology, through PC5 interface as defined in 3GPP documents.
• UE 101-A may transmit information or data to other UE (s) within the SL-U communication system through sidelink unicast, sidelink groupcast, or sidelink broadcast. For instance, UE 101-A may transmit data to UE 101-B in a sidelink unicast session.
• UE 101-A may transmit data to UE 101-B and UE 101-C in a groupcast group by a sidelink groupcast transmission session. Also, UE 101-A may transmit data to UE 101-B and UE 101-C by a sidelink broadcast transmission session.
• UE 101-B or UE 101-C may function as a Tx UE and transmit information or data
• UE 101-A may function as an Rx UE and receive information or data from UE 101-B or UE 101-C.
• Both UE 101-A and UE 101-B in the embodiments of Fig. 1 may transmit information to BS 102 and receive control information from BS 102, for example, via a Uu interface.
• BS 102 may define one or more cells, and each cell may have a coverage area. As shown in Fig. 1, both UE 101-A and UE 101-B are within the coverage of BS 102, while UE 101-C and UE 101-D are not.
• the BS 102 as illustrated and shown in Fig. 1 may not be a specific base station, but may be any base station (s) in the SL-U communication system.
• UE 101-A being within a coverage area of any one the two BSs may be called as a case that UE 101-A is within the coverage of a BS in the SL-U communication system; and only UE 101-A being outside of coverage area (s) of both BSs may be called as a case that UE 101-A is outside of the coverage of a BS in the SL-U communication system.
• UEs may operate in different modes. At least the following two sidelink resource allocation modes are defined for sidelink communication: resource allocation mode 1: a BS may schedule a sidelink resource (s) to be used by a UE for sidelink transmission (s) ; and resource allocation mode 2: a UE may determine a sidelink transmission resource (s) within sidelink resources configured by a BS or network, or pre-configured sidelink resources. In resource allocation mode 2, a BS may not schedule the sidelink resources for a UE. In Fig. 1, UE 101-A and UE 101-B may be in resource allocation mode 1, and UE 101-C and UE 101-D may be in resource allocation mode 2. In some other cases, UE 101-A and UE 101-B may also operate in resource allocation mode 2.
• mode 1 may refer to resource allocation mode 1
• mode 2 may refer to resource allocation mode 2.
• a consistent LBT failure may be detected for a BWP.
• only one carrier may be configured, and only one SL BWP is supported for one carrier. So per RB set based consistent LBT failure, instead of per SL BWP based consistent LBT failure, is one possible way-forward.
• An SL BWP may include one or more RB sets, each RB set may include the same number of RBs, or different number of RBs based on the configuration. In some embodiments, one RB may occupy 20MHz in the frequency domain.
• the expression "RB set” may also be referred to as a sub-band, a sub-channel, a set of RBs, or the like. Hereinafter in the present disclosure, “an RB set, " “a sub-band, " “a sub-channel, " or “a set of RBs” may be used interchangeably where appropriate.
• a counter (which may be different from the counter for a BWP) may be configured and accumulated for each received LBT failure indication for an RB set.
• a consistent LBT failure is triggered on the RB set.
• the consistent LBT failure for an RB set may also be referred as "a per RB set consistent LBT failure, " "an RB set consistent LBT failure” or the like.
• the present disclosure proposes some solutions for handling a consistent LBT failure on an RB set.
• Solution 1 relates to an SL UE operating in resource allocation mode 2.
• the UE may determine whether to trigger a resource (re) selection procedure or not.
• the UE may further determine how to perform the resource (re) selection.
• Solution 1-1 relates to a one-shot transmission, for example, a single medium access control protocol data unit (MAC PDU) transmission
• the MAC PDU transmission may be configured with an initial transmission, and a number of retransmissions.
• the UE may first perform the initial transmission of the MAC PDU, then perform the number of retransmissions of the MAC PDU.
• the SL UE may have selected and reserved resources for the initial transmission and the retransmissions for an SL grant on a specific RB set.
• the UE may determine the transmission status of the one-shot transmission, for example, whether the initial transmission is performed or not, or how many retransmissions are left, or the like.
• the SL UE may be triggered to perform a resource selection procedure (or a resource reselection procedure) .
• the SL UE may clear the SL grant and remove all reserved resource (s) (because no transmissions have been performed) , and trigger a resource (re) selection procedure to select new resources for the initial transmission and the number of retransmissions.
• the SL UE may be triggered to perform a resource selection procedure (or a resource reselection procedure) .
• the SL UE may clear the SL grant and remove the remaining reserved resource (s) (which is reserved for performing the remaining retransmissions of the MAC PDU) , and trigger a resource (re) selection procedure to select a new resource (s) for the remaining retransmissions.
• an SL UE may have selected three resources for a specific SL grant to perform a single MAC PDU transmission, in which one resource is for the initial transmission of the single MAC PDU transmission, and two resources are for the retransmissions of the single MAC PDU transmission.
• the SL UE may detect a consistent LBT failure is triggered for the RB set after the initial transmission of the single MAC PDU transmission, and the SL UE may clear the SL grant and remove two resources for retransmissions of the single MAC PDU transmission.
• the UE may trigger a resource selection procedure (or a resource reselection procedure) to select two new resources for the two retransmissions of the single MAC PDU transmission on an RB set with no consistent LBT failure.
• Solution 1-2 relates to a multi-shot transmission, for example, transmissions of multiple MAC PDUs.
• the transmissions of multiple MAC PDUs may be transmitted periodically, and the SL UE may have selected and reserved a series of resources for the periodic transmissions of the multiple MAC PDUs for an SL grant on a specific RB set.
• the UE may determine the transmission status of the multi-shot transmission, for example, or how many retransmissions are left, or the like.
• the SL UE may be triggered to perform a resource selection procedure (or a resource reselection procedure) .
• the SL UE may clear the SL grant and remove the remaining reserved resource (s) (the number of the remaining reserved resource (s) may range from 0 to the total number of the transmissions of the multiple MAC PDUs) , and trigger a resource (re) selection to select a new resource (s) for the number of transmissions of the multiple MAC PDUs on an RB set with no consistent LBT failure.
• an SL UE may have selected and reserved 30 resources on an RB set for a specific SL grant to perform the multi-shot transmission, and a consistent LBT failure may have occurred for the RB set after the 10 th transmission, in other words, when the first ten transmissions are performed, the SL UE may clear the SL grant and remove the remaining 20 resources for the multi-shot transmission, and trigger a resource (re) selection to select 20 new resources for the remaining 20 transmissions of the multi-shot transmission on RB set with no consistent LBT failure.
• Solution 1-3 relates to a transmission associated with a specific Layer 2 (L2) destination, or a specific LCH, or an LCH with a specific priority level.
• L2 Layer 2
• the reselected resources for the SL transmissions are only enabled for data of a specific Layer 2 (L2) destination, or a specific LCH, or an LCH with a specific priority level.
• L2 Layer 2
• the SL UE may trigger a resource selection procedure or a resource reselection procedure, to perform the rest of the transmission (s) of the initial transmission and the number of retransmissions of the one-shot transmission.
• the SL UE may trigger a resource selection procedure or a resource reselection procedure, to perform the rest of the transmission (s) of the multi-shot transmission.
• the UE may trigger a resource selection procedure or a resource reselection procedure, to perform the rest of the SL transmission.
• the SL UE may be prohibited from selecting a resource (s) on an RB set where a consistent LBT failure has occurred on the RB set, until the RB set is recovered. That is to say, UE may only select a resource (s) on an RB set with no consistent LBT failure.
• Solution 2 relates to an SL UE operating in resource allocation mode 2.
• the SL UE may perform a resource pool selection procedure when a consistent failure on an RB set is triggered (or when the UE detects a consistent LBT failure on the specific RB set) .
• An RB set with a consistent failure may be referred to as "a problematic RB set” , "an RB set with lower priority level, " or the like.
• Rule 1 in the case that a resource pool includes only one RB set, which is a problematic RB set, the resource pool may be prohibited from being selected, until the RB set in the resource pool is recovered, or until the RB set is available. In the case that a resource pool includes two or more RB sets, and all the RB sets in the resource pool are problematic RB sets, the resource pool may be prohibited from being selected.
• a resource pool may include another RB set (s) in addition to a problematic RB set (s) , in other words, one or more RB set (s) in the resource pool are not problematic, and in this case, the resource pool may be prohibited from being selected.
• the resource pool may be determined to be associated with a lower priority level compared with another resource pool with no problematic RB set.
• a resource pool with no problematic RB set (s) may have a higher priority level, for example, "0" ; a resource pool with both problematic RB set (s) and a normal RB set (s) (i.e., RB set (s) with no consistent LBT failure) may have a lower priority level, for example, "1" .
• the resource pool with both a problematic RB set (s) and a normal RB set (s) may be labeled with "problem" , and considered as a problematic resource pool; while the resource pool with no problematic RB set (s) may not be labeled.
• the SL UE may prefer a resource pool with a higher priority level (such as "0" ) over the resource pool with a lower priority level (such as "1" ) . In the case that no resource pool with a higher priority level has been selected, the SL UE may then select a resource pool with a lower priority level.
• a higher priority level such as "0"
• a lower priority level such as "1”
• the RB set (s) with a consistent LBT failure may be labeled as a problem, that is, the RB set (s) may be considered as a problematic RB set (s) , and may be determined to be associated with a lower priority level (such as "low” ) compared with another RB set (s) with no consistent LBT failure (such as "high” ) in the problematic resource pool. Accordingly, when the SL UE selects a resource pool with a lower priority level, the SL UE may select an RB set with a higher priority level (such as "high” ) in the resource pool.
• Solution 3 relates to an SL UE operating in resource allocation mode 1.
• a UE in mode 1 such as UE 101-A in Fig. 1
• the SL UE may transmit an indication to the BS, or to the network, to indicate the consistent LBT failure on the RB set.
• the indication may be a MAC CE, or RRC signalling, and the indication may be transmitted on the Uu interface between the BS and the UE.
• the indication may include the consistent LBT failure information and the corresponding RB set (s) , for example, the number of LBT failure indications, the identifier of the RB set (s) , or the like.
• the SL UE may receive an indication from a peer UE, for example, another SL UE, which may include a consistent LBT failure report.
• the consistent LBT failure report from the peer UE may include the number of LBT failure indications, the identifier of the RB set (s) , or the like.
• the peer UE may either operate in resource allocation mode 1 or in resource allocation mode 2.
• the SL UE may be triggered to transmit a report to the BS about the consistent LBT failure information and corresponding RB set (s) of the peer UE.
• the BS may schedule a sidelink resource (s) to be used by a UE in resource allocation mode 1 for sidelink transmission (s) , after receiving the indication (or report) from the UE, the BS may indicate the UE to use another sidelink resource (s) .
• Solution 4 relates to recovery from a consistent LBT failure on an RB set, and relates to an SL UE operating in resource allocation mode 1 or mode 2.
• Solution 4-1 relates to an SL UE operating in resource allocation mode 1 or resource allocation mode 2.
• the SL UE may start a timer, which may be referred to as a prohibit timer.
• the length of the timer may be indicated by the network, for example, via an indication from the BS, or may be preconfigured, or configured.
• the SL UE When the timer is running, i.e., during the time period of the timer, the SL UE may be prohibited from selecting the specific RB set during a resource selection procedure or a resource reselection procedure. The resources in the specific RB set are prohibited from being used for SL communication.
• the SL UE may consider that the specific RB set is recovered, i.e., the specific RB set may be selected by the SL UE during a resource selection procedure or a resource reselection procedure, or may be used for SL communication.
• the specific RB set may also be referred to as available when the timer expires.
• Solution 4-2 relates to an SL UE operating in resource allocation mode 1 or resource allocation mode 2.
• the SL UE may perform an LBT procedure on the RB set continuously.
• the SL UE may perform an LBT procedure on the RB set in a periodical manner.
• the LBT procedure may be any type of LBT procedure, for example, LBT type 1, LBT type 2 a, LBT type b, LBT category 1 (Cat. 1) , LBT Cat. 2, LBT Cat. 4, etc.
• the periodicity for performing the LBT procedure may be indicated by the BS, by the network, or may be configured or preconfigured.
• a first threshold and a time period may be used to determine whether the RB set is recovered or not.
• the first threshold may be associated with an accumulated LBT success number.
• the value of the first threshold and/or the time period may be indicated by the BS, by the network, or may be configured or preconfigured. In the case that during the time period, the accumulated LBT success number is larger than the first threshold, the RB set is regarded as recovered, or as available, and may be used for SL transmission.
• a second threshold and a time period may be used to determine whether the RB set is recovered or not.
• the second threshold may be associated with an accumulated LBT failure number.
• the value of the second threshold and/or the time period may be indicated by the BS, by the network, or may be configured or preconfigured. In the case that during the time period, the accumulated LBT failure number is smaller than the second threshold, the RB set is considered as recovered, or as available, and may be used for SL transmission.
• Solution 4-3 relates to an SL UE operating in resource allocation mode 1 or resource allocation mode 2.
• the SL UE may perform a CBR measurement on the specific RB set continuously, such as in a periodical manner.
• a threshold associated with the CBR measurement may be indicated by the BS, by the network, or may be configured or preconfigured.
• the RB set is considered as recovered, or as available, and may be used for SL transmission.
• Solution 4-4 relates to an SL UE operating in resource allocation mode 1.
• the SL UE in mode 1 may receive an indication from the BS, which may indicate that the specific RB set is recovered or available. The UE then may consider the specific RB set as recovered or available. The BS may determine whether the specific RB set is recovered or available by collecting other SL-U UE transmission information on the specific RB set.
• Solution 4-5 relates to an SL UE operating in resource allocation mode 1.
• the SL UE in mode 1 may receive an indication from the BS, which may indicate at least one of the following:
• an LBT sub-channel (or LBT BWP) including the specific RB set is reconfigured.
• the UE may consider that the specific RB set as recovered or available.
• the UE may have labeled the specific RB set as problematic, or determined that the RB set is associated with a lower priority level (such as "low” )
• the UE may remove the problematic label, or determine that the RB set is associated with a higher priority level (such as "high” ) .
• the UE may have labeled the resource pool as problematic, or determined that the resource pool is associated with a lower priority level (such as "1" ) compared with other resource pools, after the resource pool is recovered, the UE may remove the problematic label, or determine that the resource pool is associated with a higher priority level (such as "0" ) .
• Solution 5 relates to an SL UE operating in resource allocation mode 1.
• a consistent LBT failure is triggered.
• the UE may trigger a consistent LBT failure for the SL BWP.
• the UE may declare an SL BWP failure, that is, the UE may consider that the SL BWP cannot be used anymore.
• a consistent LBT failure is triggered for all RB sets on a configured SL-BWP or SL carrier
• a consistent LBT failure for the configured SL BWP is triggered.
• the UE may declare the SL carrier is a failure, i.e., the SL carrier cannot be used anymore. The UE may report to higher layers, and report to the BS to require a new SL carrier for SL communication.
• Fig. 2 illustrates a method performed by a UE for handling a consistent LBT failure according to some embodiments of the present disclosure.
• the UE may detect a consistent LBT failure on an RB set of an SL BWP.
• the UE may perform one of the following: triggering a resource selection procedure; triggering a resource pool selection procedure; transmitting a first indication indicating the consistent LBT failure on the RB set; determining the RB set as recovered in response to one or more conditions being fulfilled; or triggering a consistent LBT failure for the SL BWP or declare an SL BWP failure.
• the resource selection procedure may include at least one of the following: performing a resource selection procedure for remaining transmission (s) on an RB set with no consistent LBT failure for a one-shot transmission; performing a resource selection procedure for reserved resource (s) on the RB set with no consistent LBT failure for a multi-shot transmission; or performing a resource selection procedure for remaining transmission (s) on the RB set with no consistent LBT failure, wherein the remaining transmission (s) is associated with at least one of: a specific destination, a specific LCH, or an LCH with a specific priority level.
• the UE may perform a resource selection procedure for remaining transmissions (or remaining retransmissions) for a single MAC PDU transmission, and the UE may perform the resource selection procedure on an RB set with no consistent LBT failure.
• the UE may perform a resource selection procedure for remaining transmissions of a multiple MAC PDU transmissions (i.e., periodical MAC PDU transmissions) on an RB set with no consistent LBT failure.
• the UE may performing a resource selection procedure for remaining transmission (s)
• the resource pool selection procedure includes one of the following: prohibiting selection of a resource pool including the RB set; or selecting the resource pool including the RB set in the case that no other resource pool is available and the resource pool includes other RB sets with no consistent LBT failure.
• the resource pool including the RB set is determined with a lower priority level compared with other resource pool (s) with no consistent LBT failure on any RB set in the other resource pool (s) .
• the RB set in the resource pool is determined with a lower priority level compared with other RB set (s) in the resource pool.
• the first indication includes a MAC CE or RRC signalling.
• the one or more conditions include: a prohibit timer being expired (for example, solution 4-1) ; an LBT success number associated with the RB set being higher than a first threshold (for example, solution 4-2) ; an LBT failure number associated with the RB set being lower than a second threshold (for example, solution 4-2) ; a result of a CBR measurement on that RB set being lower than a third threshold (for example, solution 4-3) ; a second indication from the BS indicating that the RB set is recovered (for example, solution 4-4) ; a third indication from the BS indicating that at least one of the RB set, a resource pool of the RB set, or the SL BWP is reconfigured (for example, solution 4-5) .
• the processor in the case that a consistent LBT failure on each RB set of the SL BWP is detected, the processor is further configured to: trigger a consistent LBT failure for the SL BWP; or declare an SL BWP failure.
• the UE may transmit a fourth indication indicating the consistent LBT failure for the SL BWP.
• Fig. 3 illustrates a method performed by a BS for handling a consistent LBT failure according to some embodiments of the present disclosure.
• the BS may receive, from a UE, a first indication indicating a consistent LBT failure on an RB set of an SL BWP; and perform one of the following: transmitting, to the UE, a second indication indicating that the RB set is recovered, or a third indication indicating that at least one of the RB set, a resource pool of the RB set, or the SL BWP is reconfigured; or receiving, from the UE, a fourth indication indicating a consistent LBT failure on each RB set of the SL BWP; and the indicating another SL BWP to the UE.
• Fig. 4 illustrates a simplified block diagram of an exemplary apparatus according to some embodiments of the present disclosure.
• an example of the apparatus 400 may include at least one processor 404 and at least one transceiver 402 coupled to the processor 404.
• the apparatus 400 may be a UE, a BS, a RAN node, a source node, a target node, a third node, or any other device with similar functions.
• the transceiver 402 may be divided into two devices, such as a receiving circuitry and a transmitting circuitry.
• the apparatus 400 may further include an input device, a memory, and/or other components.
• the apparatus 400 may be a UE.
• the transceiver 402 and the processor 404 may interact with each other so as to perform the operations of the UE described in any of Figs. 1-4.
• the apparatus 400 may be a node.
• the transceiver 402 and the processor 404 may interact with each other so as to perform the operations of the node described in any of Figs. 1-3.
• the apparatus 400 may further include at least one non-transitory computer-readable medium.
• the non-transitory computer-readable medium may have stored thereon computer-executable instructions to cause the processor 404 to implement the method with respect to the UE as described above.
• the computer-executable instructions when executed, cause the processor 404 interacting with transceiver 402 to perform the operations of the UE described in any of Figs. 1-3.
• the non-transitory computer-readable medium may have stored thereon computer-executable instructions to cause the processor 404 to implement the method with respect to the node as described above.
• the computer-executable instructions when executed, cause the processor 404 interacting with transceiver 402 to perform the operations of the node described in any of Figs. 1-3.
• controllers, flowcharts, and modules may also be implemented on a general purpose or special purpose computer, a programmed microprocessor or microcontroller and peripheral integrated circuit elements, an integrated circuit, a hardware electronic or logic circuit such as a discrete element circuit, a programmable logic device, or the like.
• any device that has a finite state machine capable of implementing the flowcharts shown in the figures may be used to implement the processing functions of the present disclosure.

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• 2022
  • 2022-07-29 EP EP22952455.8A patent/EP4562968A4/de active Pending
  • 2022-07-29 GB GB2418673.6A patent/GB2635049A/en active Pending
  • 2022-07-29 WO PCT/CN2022/108893 patent/WO2024021004A1/en not_active Ceased
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