MOBILITY FOR A MOBILE INTEGRATED ACCESS AND BACKHAUL CELL

Various aspects of the present disclosure generally relate to wireless communication. In some aspects, a user equipment (UE) may receive an indication that a cell is associated with a mobile integrated access and backhaul (IAB) status. The UE may perform a cell selection or reselection operation based at least in part on an onboard status between the UE and the cell and based at least in part on the cell being associated with the mobile IAB status. Numerous other aspects are described.

FIELD OF THE DISCLOSURE

Aspects of the present disclosure generally relate to wireless communication and to techniques and apparatuses for mobility for a mobile integrated access and backhaul cell.

BACKGROUND

SUMMARY

Some aspects described herein relate to a method of wireless communication performed by a user equipment (UE). The method may include receiving an indication that a cell is associated with a mobile integrated access and backhaul (IAB) status indicating that the cell is a mobile cell. The method may include performing a cell selection or reselection operation based at least in part on an onboard status between the UE and the cell and based at least in part on the cell being associated with the mobile IAB status, wherein the onboard status indicates that the UE is onboard a moving entity.

Some aspects described herein relate to a UE for wireless communication. The UE may include a memory and one or more processors coupled to the memory. The one or more processors may be configured to receive an indication that a cell is associated with a mobile IAB status indicating that the cell is a mobile cell. The one or more processors may be configured to perform a cell selection or reselection operation based at least in part on an onboard status between the UE and the cell and based at least in part on the cell being associated with the mobile IAB status, wherein the onboard status indicates that the UE is onboard a moving entity.

Some aspects described herein relate to a non-transitory computer-readable medium that stores a set of instructions for wireless communication by a UE. The set of instructions, when executed by one or more processors of the UE, may cause the UE to receive an indication that a cell is associated with a mobile IAB status indicating that the cell is a mobile cell. The set of instructions, when executed by one or more processors of the UE, may cause the UE to perform a cell selection or reselection operation based at least in part on an onboard status between the UE and the cell and based at least in part on the cell being associated with the mobile IAB status, wherein the onboard status indicates that the UE is onboard a moving entity.

Some aspects described herein relate to an apparatus for wireless communication. The apparatus may include means for receiving an indication that a cell is associated with a mobile IAB status indicating that the cell is a mobile cell. The apparatus may include means for performing a cell selection or reselection operation based at least in part on an onboard status between the apparatus and the cell and based at least in part on the cell being associated with the mobile IAB status, wherein the onboard status indicates that the UE is onboard a moving entity.

DETAILED DESCRIPTION

A user equipment (UE) may access a wireless network via a cell provided by a network node, such as an integrated access and backhaul (IAB) node. In some deployments, a network node (and a cell provided by the network node) can be mobile, meaning that the network node can move with an entity to which the network node is affixed or associated. A UE may be onboard the entity to which the network node is affixed, meaning that the UE may move with the network node and the cell. This may be referred to as the UE having an onboard status with regard to the network node. In some examples, the UE may be in a radio resource control (RRC) idle mode or an RRC inactive mode, meaning that the UE performs cell selection and reselection operations such that the UE remains camped on a cell. Legacy cell selection and reselection operations may be suboptimal for a UE that is associated with an onboard status, since the UE may be likely to remain in coverage of a mobile IAB node and may be likely to detect many different cells as a result of cell selection measurements. However, the UE may not have information indicating that the UE is associated with the onboard status. Thus, the UE cannot perform cell selection and reselection operations that are suitable for UEs associated with an onboard status, which reduces efficiency of network resource usage and causes unnecessary cell selection or reselection operations.

Some techniques described herein provide cell selection and reselection operations based at least in part on an onboard status between a UE and a cell, and based at least in part on the cell being associated with a mobile IAB status (e.g., the cell being associated with a mobile IAB node). For example, a UE may receive an indication that the cell is associated with the mobile IAB status. The UE may perform a cell selection or reselection operation based at least in part on the cell being associated with the mobile IAB status and based at least in part on an onboard status between the UE and the cell. By performing the cell selection or reselection operation based at least in part on the mobile IAB status and the onboard status, efficiency of network resource usage is increased and occurrence of unnecessary cell selection or reselection operations is reduced.

Some techniques described herein provide a determination that a UE is associated with an onboard status with regard to a cell. For example, the UE may determine that the UE is associated with the onboard status based on detecting the cell for a first threshold length of time. As another example, the UE may determine that the UE is associated with the onboard status based on camping on the cell for a second threshold length of time. By determining, at the UE, that the UE is associated with an onboard status, processing load and complexity are reduced at the cell.

In some aspects, the UE120may include a communication manager140. As described in more detail elsewhere herein, the communication manager140may receive an indication that a cell is associated with a mobile integrated access and backhaul (IAB) status; and perform a cell selection or reselection operation based at least in part on an onboard status between the UE and the cell and based at least in part on the cell being associated with the mobile IAB status. Additionally, or alternatively, the communication manager140may perform one or more other operations described herein.

In some aspects, the UE120includes means for receiving (e.g., using antenna252, modem254, MIMO detector256, receive processor258, controller/processor280, and/or the like) an indication that a cell is associated with a mobile IAB status; and/or means for performing (e.g., using antenna252, modem254, MIMO detector256, receive processor258, controller/processor280, and/or the like) a cell selection or reselection operation based at least in part on an onboard status between the UE and the cell and based at least in part on the cell being associated with the mobile IAB status. The means for the UE120to perform operations described herein may include, for example, one or more of communication manager140, antenna252, modem254, MIMO detector256, receive processor258, transmit processor264, TX MIMO processor266, controller/processor280, or memory282.

FIG.4is a diagram illustrating examples400of radio access networks, in accordance with the present disclosure.

As shown by reference number405, a traditional (e.g., 3G, 4G, or LTE) radio access network may include multiple network nodes410(e.g., base stations) (illustrated as access nodes (AN)), where each network node410communicates with a core network via a wired backhaul link415, such as a fiber connection. A network node410may communicate with a UE420via an access link425, which may be a wireless link. In some aspects, a network node410shown inFIG.4may be a network node110shown inFIG.1. In some aspects, a UE420shown inFIG.4may be a UE120shown inFIG.1.

As shown by reference number430, a radio access network may include a wireless backhaul network, sometimes referred to as an integrated access and backhaul (IAB) network. In an IAB network, at least one network node is an anchor network node435that communicates with a core network via a wired backhaul link440, such as a fiber connection. An anchor network node435may also be referred to as an IAB donor (or IAB-donor). The IAB network may include one or more non-anchor network nodes445, sometimes referred to as relay nodes, relay base stations or IAB nodes (or IAB-nodes). The non-anchor network node445may communicate directly or indirectly with the anchor network node435via one or more backhaul links450(e.g., via one or more non-anchor network nodes445) to form a backhaul path to the core network for carrying backhaul traffic. Backhaul link450may be a wireless link. Anchor network node(s)435and/or non-anchor network node(s)445may communicate with one or more UEs455via access links460, which may be wireless links for carrying access traffic. In some aspects, an anchor network node435and/or a non-anchor network node445shown inFIG.4may be a network node110shown inFIG.1. In some aspects, a UE455shown inFIG.4may be a UE120shown inFIG.1.

As shown by reference number465, in some aspects, a radio access network that includes an IAB network may utilize millimeter wave technology and/or directional communications (e.g., beamforming) for communications between network nodes and/or UEs (e.g., between two network nodes, between two UEs, and/or between a network node and a UE). For example, wireless backhaul links470between network nodes may use millimeter wave signals to carry information and/or may be directed toward a target network node using beamforming. Similarly, the wireless access links475between a UE and a network node may use millimeter wave signals and/or may be directed toward a target wireless node (e.g., a UE and/or a network node). In this way, inter-link interference may be reduced.

The configuration of network nodes and UEs inFIG.4is shown as an example, and other examples are contemplated. For example, one or more base stations illustrated inFIG.4may be replaced by one or more UEs that communicate via a UE-to-UE access network (e.g., a peer-to-peer network or a device-to-device network). In this case, an anchor node may refer to a UE that is directly in communication with a network node (e.g., an anchor network node or a non-anchor network node).

FIG.5is a diagram illustrating an example500of an IAB network architecture, in accordance with the present disclosure.

As shown inFIG.5, an IAB network may include an IAB donor505(shown as IAB-donor) that connects to a core network via a wired connection (shown as a wireline backhaul). For example, an Ng interface of an IAB donor505may terminate at a core network. Additionally, or alternatively, an IAB donor505may connect to one or more devices of the core network that provide a core access and mobility management function (AMF). In some aspects, an IAB donor505may include a network node110, such as an anchor network node, as described above in connection with4. As shown, an IAB donor505may include a CU, which may perform access node controller (ANC) functions and/or AMF functions. The CU may configure a DU of the IAB donor505and/or may configure one or more IAB nodes510(e.g., a mobile terminal (MT) and/or a DU of an IAB node510) that connect to the core network via the IAB donor505. Thus, a CU of an IAB donor505may control and/or configure the entire IAB network that connects to the core network via the IAB donor505, such as by using control messages and/or configuration messages (e.g., a radio resource control (RRC) configuration message or an F1 application protocol (F1-AP) message).

As further shown inFIG.5, the IAB network may include IAB nodes510(shown as IAB-node 1, IAB-node 2, and IAB-node 3) that connect to the core network via the IAB donor505. As shown, an IAB node510may include mobile termination (MT) functions (also sometimes referred to as UE functions (UEF)) and may include DU functions (also sometimes referred to as access node functions (ANF)). The MT functions of an IAB node510(e.g., a child node) may be controlled and/or scheduled by another IAB node510(e.g., a parent node of the child node) and/or by an IAB donor505. The DU functions of an IAB node510(e.g., a parent node) may control and/or schedule other IAB nodes510(e.g., child nodes of the parent node) and/or UEs120. Thus, a DU may be referred to as a scheduling node or a scheduling component, and an MT may be referred to as a scheduled node or a scheduled component. In some aspects, an IAB donor505may include DU functions and not MT functions. That is, an IAB donor505may configure, control, and/or schedule communications of IAB nodes510and/or UEs120. A UE120may include only MT functions, and not DU functions. That is, communications of a UE120may be controlled and/or scheduled by an IAB donor505and/or an IAB node510(e.g., a parent node of the UE120).

When a first node controls and/or schedules communications for a second node (e.g., when the first node provides DU functions for the second node's MT functions), the first node may be referred to as a parent node of the second node, and the second node may be referred to as a child node of the first node. A child node of the second node may be referred to as a grandchild node of the first node. Thus, a DU function of a parent node may control and/or schedule communications for child nodes of the parent node. A parent node may be an IAB donor505or an IAB node510, and a child node may be an IAB node510or a UE120. Communications of an MT function of a child node may be controlled and/or scheduled by a parent node of the child node.

As further shown inFIG.5, a link between a UE120(e.g., which only has MT functions, and not DU functions) and an IAB donor505, or between a UE120and an IAB node510, may be referred to as an access link515. Access link515may be a wireless access link that provides a UE120with radio access to a core network via an IAB donor505, and optionally via one or more IAB nodes510. Thus, the network illustrated in 5 may be referred to as a multi-hop network or a wireless multi-hop network.

As further shown inFIG.5, a link between an IAB donor505and an IAB node510or between two IAB nodes510may be referred to as a backhaul link520. Backhaul link520may be a wireless backhaul link that provides an IAB node510with radio access to a core network via an IAB donor505, and optionally via one or more other IAB nodes510. In an IAB network, network resources for wireless communications (e.g., time resources, frequency resources, and/or spatial resources) may be shared between access links515and backhaul links520. In some aspects, a backhaul link520may be a primary backhaul link or a secondary backhaul link (e.g., a backup backhaul link). In some aspects, a secondary backhaul link may be used if a primary backhaul link fails, becomes congested, and/or becomes overloaded, among other examples. For example, a backup link525between IAB-node 2 and IAB-node 3 may be used for backhaul communications if a primary backhaul link between IAB-node 2 and IAB-node 1 fails. As used herein, a node or a wireless node may refer to an IAB donor505or an IAB node510.

In some aspects, a node may be a mobile IAB node. A mobile IAB node may include an IAB node (e.g., IAB donor505or IAB node510) that is associated with (e.g., affixed to, in motion with) a moving entity, such as a vehicle (e.g., a bus, a train, a ship, an airship, a balloon, etc.). In some aspects, a mobile IAB node may not provide connectivity for downstream IAB nodes (e.g., only for UEs). A mobile IAB node may provide a cell via which UEs120may establish access links515with the mobile IAB node. In some situations, a UE120may move with a mobile IAB node (and thus the cell provided by the mobile IAB node), for example, because the UE120is located in or on the moving entity. In some other situations, a UE120may not move with a mobile IAB node, for example, because the UE120is not located in or on the moving entity. An IAB node may transmit an indication that the IAB node is a mobile IAB node. For example, the IAB node may transmit the indication via broadcast system information, RRC signaling, or the like. The UE120may perform various operations based at least in part on this indication, as described elsewhere herein.

FIG.6illustrates an example600of a wireless network (e.g., wireless network100) in which a UE (e.g., a UE120) may support additional communication modes, in accordance with the present disclosure. The UE may be communicatively connected with one or more network nodes110in the wireless network. For example, the UE may be connected to the one or more network nodes110in a dual connectivity configuration. In this case, a first network node110may serve the UE as a master node and a second network node110may serve the UE as a secondary node.

As illustrated inFIG.6, the UE may support a connected communication mode (e.g., an RRC active mode602), an idle communication mode (e.g., an RRC idle mode604), and an inactive communication mode (e.g., an RRC inactive mode606). RRC inactive mode606may functionally reside between RRC active mode602and RRC idle mode604.

The UE may transition between different modes based at least in part on various commands and/or communications received from the one or more network nodes110. For example, the UE may transition from RRC active mode602or RRC inactive mode606to RRC idle mode604based at least in part on receiving an RRCRelease communication. As another example, the UE may transition from RRC active mode602to RRC inactive mode606based at least in part on receiving an RRCRelease with suspendConfig communication. As another example, the UE may transition from RRC idle mode604to RRC active mode602based at least in part on receiving an RRCSetupRequest communication. As another example, the UE may transition from RRC inactive mode606to RRC active mode602based at least in part on receiving an RRCResumeRequest communication.

When transitioning to RRC inactive mode606, the UE and/or the one or more network nodes110may store a UE context (e.g., an access stratum (AS) context and/or higher-layer configurations). This permits the UE and/or the one or more network nodes110to apply the stored UE context when the UE transitions from RRC inactive mode606to RRC active mode602in order to resume communications with the one or more network nodes110, which reduces latency of transitioning to RRC active mode602relative to transitioning to the RRC active mode602from RRC idle mode604.

In some cases, the UE may communicatively connect with a new master node when transitioning from RRC idle mode604or RRC inactive mode606to RRC active mode602(e.g., a master node that is different from the last serving master node when the UE transitioned to RRC idle mode604or RRC inactive mode606). In this case, the new master node may be responsible for identifying a secondary node for the UE in the dual connectivity configuration.

The UE may start in the RRC idle mode604when the UE initially camps on a cell. “Cell selection” is a mobility procedure for a UE to identify a cell on which to camp. Cell selection is applicable after a UE is powered on, after a UE leaves the RRC activated mode602, and after the UE returns to an area of coverage. While camped on a cell, the UE may read system information, perform registration area updates with a core network, apply discontinuous reception (DRX) for paging, and monitor a physical downlink control channel (PDCCH) for downlink control information (DCI) or core network paging. The UE may switch from camping on one cell to camping on another cell by performing cell reselection. Cell reselection is a mobility procedure for UEs in the RRC idle mode604or the RRC inactive mode606. Cell selection may include: scanning radio frequency channels within supported frequency bands of the UE according to a synchronization raster; searching for one or more synchronization signal blocks at each carrier frequency; identifying a strongest cell based on searching for the one or more synchronization signal blocks; and camping on the strongest cell if the strongest cell is a “suitable cell” or an “acceptable cell.” Cell reselection may include: performing measurements on a set of cells, ranking the set of cells based at least in part on the measurements, and camping on a cell selected from the ranked set of cells. Cell selection and reselection may be performed according to various rules and criteria, such as an Srxlev criterion, an Squal criterion, a Qrlxevmin criterion, a Qqualmin criterion, a prioritization rule (indicating that particular cells or particular types of cells should be prioritized or deprioritized for selection or reselection), a reselection timer (e.g., which may correspond to a mobility state of the UE), a time interval for measurement, or the like.

FIG.7is a diagram illustrating an example700of signaling associated with determination of an onboard status and cell selection or reselection, in accordance with the present disclosure. Example700includes a UE (e.g., UE120) and a network node (e.g., network node110, IAB donor505, IAB node510). The network node may be a mobile IAB node, as described above. The network node may implement a cell. It should be understood that references to communications between the UE and the network node also include the same communications between the UE and the cell implemented by the network node, and vice versa. Operations described herein as being performed by the cell may be performed by the network node implementing the cell.

As shown by reference number705, the network node may output, and the UE may receive, an indication that the cell is associated with a mobile IAB status. For example, the indication may indicate that the network node is a mobile IAB node. The network node may output the indication via any suitable form of signaling, such as broadcast system information (e.g., system information block 1 (SIB1), RRC signaling, or the like). In some aspects, the indication may indicate one or more cells that are associated with the mobile IAB status. In some aspects, the indication may indicate a cell, other than a cell implemented by the network node that outputs the indication, that is associated with a mobile IAB status. For example, the indication may identify a list of candidate cells with mobile IAB statuses. For example, the UE may receive assistance information indicating one or more cells or frequencies that may have a mobile IAB status (e.g., may belong to a mobile cell). This information can be provided in system information (SI) broadcast by the cell on which the UE camps (e.g., SIB2, SIB3, SIB4, or another SIB), in a dedicated RRC message (such as an RRC release message) when the UE is connected to the network, via a reconfiguration message, or in an operations, administration, and maintenance (OAM) configuration. Providing the list of cells with mobile IAB statuses may reduce power consumption by the UE in connection with acquiring SIBs of each neighbor cell to determine whether each neighbor cell transmits an indication of a mobile IAB status. In some aspects, the UE may attempt to read system information from one or more cells (e.g., neighboring cells) to determine whether the one or more cells are associated with a mobile IAB status. For example, the UE may read the system information prior to performing initial access with the one or more cells. The UE may use this system information to identify an onboard status with the one or more cells, as described below.

As shown by reference number710, the UE may identify an onboard status between the UE and the cell (e.g., the network node). The identification of the onboard status can occur before selecting the cell for camping (e.g., during measurement of the cell), immediately before selecting the cell for camping, or after selecting the cell for camping. In some aspects, the onboard status between the UE and the cell may indicate that the UE is onboard a moving entity to which the network node is affixed or associated. In some aspects, the onboard status between the UE and the cell may indicate that the UE is expected to remain in a coverage area of the cell for a threshold length of time.

As shown by reference number715, in some aspects, the UE may identify the onboard status based on detecting the cell for a first threshold length of time. For example, the UE may detect the cell for a first threshold length of time, and may identify the onboard status in response to detecting the cell for the first threshold length of time. The first threshold length of time may be configured (e.g., the network node may output, and the UE may receive, configuration information indicating the first threshold length of time). In some aspects, the onboard status is based at least in part on detecting the cell for the first threshold length of time while the UE is camped on another cell not associated with the mobile IAB status. For example, the other cell may be a stationary cell (e.g., a cell not implemented by a mobile IAB node). Thus, the UE may identify an onboard status, while camped on a stationary cell, based at least in part on observing a mobile IAB cell for a second threshold length of time. The UE may be in a normal-mobility state, a medium-mobility state, or a high-mobility state (as defined, for example, in 3GPP Technical Specification 38.304) during the identification of the onboard status. Mobility states may correspond to how frequently the UE has reselected a new cell (on which to camp) within a configured time interval. In some aspects, the determination of the onboard status based on detecting the cell for the first threshold length of time may be applicable to all mobility states (including a normal-mobility state, a medium-mobility state, or a high-mobility state). In some other aspects, the determination of the onboard status based on detecting the cell for the first threshold length of time may be applicable to a proper subset of the mobility states (e.g., one or more of the normal-mobility state, the medium-mobility state, or the high-mobility state). For example, the UE may determine the onboard status based on detecting the cell for the first threshold length of time only if the UE is in a medium-mobility state or a high-mobility state. Additionally, or alternatively, a parameter used to determine the onboard status (such as a length of the first threshold length of time, a measurement threshold, a measurement offset, or the like) may be derived from a current mobility state of the UE.

As mentioned, the UE may identify the onboard status based at least in part on detecting the cell for the first threshold length of time. “Detecting the cell” may include detecting a signal transmitted by the cell. In some aspects, “detecting the cell” may include performing a measurement. For example, the UE may detect the cell when the UE detects a signal transmitted by the cell, and when a measurement on the signal (e.g., an RSRP measurement, an RSRQ measurement, an Srxlev measurement, an Squal measurement, or a combination thereof) satisfies a measurement threshold. Additionally, or alternatively, the UE may detect the cell when a variation in a measurement on the signal is lower than a threshold.

As shown by reference number720, in some aspects, the UE may identify the onboard status (or may maintain an onboard status) for a cell based at least in part on camping on the cell for a second threshold length of time. In some aspects, the second threshold length of time may be different than the first threshold length of time. For example, the second threshold length of time (e.g., the time duration to declare or maintain an onboard status if already camped on a cell) may be shorter than the first threshold length of time (e.g., the time duration to identify a cell as having an onboard status when the UE initially camps on a stationary cell). A length of the second threshold length of time may be configured (e.g., the UE may receive configuration information indicating the length of the second threshold length of time). In some aspects, the length of the second threshold length of time may be based at least in part on a mobility state of the UE. For example, the length of the second threshold length of time may be different in a first mobility state (e.g., a high-mobility state) than in a second mobility state (e.g., a normal-mobility state).

As shown by reference number725, the UE may perform a cell selection or reselection operation based at least in part on the onboard status and based at least in part on the cell being associated with the mobile IAB status. Details regarding the cell selection operation and the cell reselection operation are provided below.

In some aspects, the UE may prioritize selecting or reselecting cells associated with the mobile IAB status over stationary cells. For example, the UE may perform this prioritization by assigning a higher (or highest) absolute priority to cells or frequencies associated with the mobile IAB status. In this example, a rule may be defined indicating to assign a highest priority to cells associated with a mobile IAB status (or to associated frequencies), or appropriate parameters may be configured (e.g., offsets, or scaling factors, or absolute values) for application to cells associated with mobile IAB status (or associated frequencies). In some aspects, the higher absolute priority may be configurable (e.g., the UE may assign a configured absolute priority to a given cell or frequency that is associated with the mobile IAB status). As another example, when ranking cells for cell reselection (e.g., based at least in part on RSRP measurements of the cells), cells associated with a mobile IAB status may be assigned a higher (e.g., configurable) or highest rank relative to stationary cells. In this example, a rule can be defined indicating to assign a highest rank to cells associated with a mobile IAB status (or to associated frequencies), or appropriate parameters may be configured (e.g., offsets, or scaling factors, or absolute values) for ranking of cells associated with mobile IAB status (or associated frequencies). As yet another example, the UE may select a cell having a mobile IAB status for which a value (e.g., an R value, which may be derived from an RSRP measurement quantity Qmeas, a Qoffset value, and/or a Qoffsettempvalue) is within a range (e.g., a range indicated by a rangeToBestCell parameter or a parameter similar to rangeToBestCell) of a cell having a best value.

In some aspects, the UE may determine a mobility state (as described above) based at least in part on the onboard status. For example, upon identifying an onboard status, the UE may assume a changed mobility state. For example, the UE may be camped on a stationary cell, and may determine a medium-mobility state or a high-mobility state. Upon entering the onboard status, the UE may determine a normal-mobility state (e.g., on the expectation that the UE will be camping for a relatively longer period of time on the same cell since the UE has an onboard status with regard to the cell). This may have an impact on reselection timers or hysteresis values of the cell selection operation or the cell reselection operation, as described elsewhere herein. For example, the UE may modify the reselection timer or hysteresis value. In some aspects, a parameter used to determine the mobility state may be based at least in part on the onboard status. For example, a parameter used to determine the mobility state (such as a time duration or a number of reselections) may be adjusted or selected in accordance with the mobility state (e.g., different values of the parameters may be used for different mobility states). As another example, a rule may be defined such that a reselection between cells associated with onboard statuses does not count toward a parameter used to determine the mobility state. For example, the UE may not consider consecutive reselections of mobile IAB cells for mobility state detection criteria. This may avoid unnecessary elevation of the mobility state when a mobile IAB cell's cell identifier changes, for example, due to the mobile IAB cell's DU switching from one CU to another CU.

In some aspects, as mentioned above, the UE may reselect from a first cell associated with a mobile IAB node to a second cell associated with a mobile IAB node. For example, the UE may have the onboard status with regard to the first cell. This may occur, for example, because a DU of the mobile IAB node may migrate from a first CU to a second CU (leading to a change in a cell identifier from the first cell to the second cell), or because of a cell identifier collision causing a change in a cell identifier from the first cell to the second cell. In this example, the UE may maintain the onboard status when reselecting from a first cell associated with a mobile IAB node to a second cell associated with a mobile IAB node. Additionally, or alternatively, the UE may reset a timer associated with the onboard status (e.g., the second threshold length of time), and may identify whether the UE is associated with an onboard status with regard to the second cell. For example, the UE may reset its timer and attempt to determine whether the UE has the onboard status with respect to a newly selected mobile IAB cell.

In some aspects, the UE may relax measurements, or refrain from relaxing measurements, based at least in part on the onboard status. Typically, a UE can relax measurements (referred to herein as using a baseline measurement configuration) when in a low-mobility state (which is different than the normal-mobility, medium-mobility, and high-mobility states mentioned above), which may be defined as observing less than a threshold variation in a measurement on a serving cell for a length of time, or when the UE is not near a cell edge, which may be defined as observing a measurement (e.g., RSRP or RSRQ) of a serving cell being above a threshold for a length of time. These conditions may be satisfied after camping on a cell with an onboard status, leading to a relaxed measurement schedule (e.g., a decreased frequency of cell measurements for reselection operations). The configuration for performing relaxed measurements may be indicated by system information (e.g., SIB2). However, a cell identifier of the cell may change (e.g., as a result of a migration of an IAB DU from one CU to another CU). If the cell identifier changes frequently, then a timer parameter for cell reselection (e.g., TSearchDeltaP) may reset frequently, leading to a lack of relaxation of measurements, which may be desirable when the cell identifier changes frequently. Conversely, if the cell identifier does not change frequently, the UE may relax measurements, which may conserve power. However, there are situations in which the cell identifier changes frequently enough that a non-relaxed measurement schedule may be beneficial, but not so frequently that the UE avoids the low-mobility state. Therefore, the UE may relax measurements when the UE would actually benefit from performing more frequent measurements due to the changing cell identifier. In some aspects, the UE may not relax measurements while camped on a cell having an onboard status, which ensures that the UE can measure the cell in the event of a changed cell identifier. In some other aspects, the UE may perform cell measurements according to a measurement configuration corresponding to the onboard status. For example, upon identifying the onboard condition, the UE may apply parameters for declaring the low-mobility state or the “near a cell edge” state (e.g., detection parameters, measurement parameters, and/or evaluation parameters) that correspond to the onboard status. As another example, the UE may apply a scaling factor to a configuration for relaxed measurements, such as to reduce a duration of the relaxed measurements or to shorten the periodicity of measurements in the relaxed measurement state. As yet another example, a configuration (e.g., a relaxedMeasurement parameter in SIB2) may indicate a configuration for relaxed measurement that is specific for cells associated with the mobile IAB status (e.g., mobile IAB cells), or may indicate a configuration for relaxed measurement in a cell-specific manner (for a particular cell) or a frequency-specific manner (for a particular frequency). In some aspects, the UE may receive signaling (e.g., configuration information) indicating whether the UE should perform measurement relaxation according to a typical procedure (as defined above) or based at least in part on the onboard status.

In some aspects, the UE may not be associated with an onboard status with regard to a cell. For example, the UE may determine that a condition of the onboard status is not satisfied (as described above). In this example, the UE may use a legacy procedure for cell selection or cell reselection (e.g., a procedure that is not based on the onboard status). Alternatively, the UE may deprioritize selection or reselection to a cell associated with a mobile IAB status, which reduces the likelihood of the UE performing frequent cell reselection due to camping on a mobile IAB cell that is likely to move away from the UE.

The signaling illustrated with regard toFIG.7can be performed using any combination of system information (e.g., SIB1 or remaining minimum system information) transmitted by the cell having the onboard status, system information (e.g., SIB2, SIB3, SIB4, or another SIB) broadcasted by another cell (e.g., a stationary cell, a neighbor cell), or a dedicated RRC message (e.g., an RRC release message) provided by a serving cell of the UE. In some aspects, any one or more parameters or values described with regard toFIG.7may be defined by a preconfiguration or by a wireless communication specification.

FIG.8is a diagram illustrating an example process800performed, for example, by a UE, in accordance with the present disclosure. Example process800is an example where the UE (e.g., UE120) performs operations associated with mobility for a mobile IAB cell.

As shown inFIG.8, in some aspects, process800may include receiving an indication that a cell is associated with a mobile IAB status (block810). For example, the UE (e.g., using reception component902and/or communication manager906, depicted inFIG.9) may receive an indication that a cell is associated with a mobile IAB status, as described above. The mobile IAB status may indicate that the cell is a mobile cell.

As further shown inFIG.8, in some aspects, process800may include performing a cell selection or reselection operation based at least in part on an onboard status between the UE and the cell and based at least in part on the cell being associated with the mobile IAB status (block820). For example, the UE (e.g., using communication manager906, depicted inFIG.9) may perform a cell selection or reselection operation based at least in part on an onboard status between the UE and the cell and based at least in part on the cell being associated with the mobile IAB status, as described above. The onboard status may indicate that the UE is onboard a moving entity.

In a first aspect, process800includes detecting the cell for a first threshold length of time, wherein the onboard status is based at least in part on detecting the cell for the first threshold length of time.

In a second aspect, alone or in combination with the first aspect, the onboard status is based at least in part on detecting the cell for the first threshold length of time while the UE is camped on another cell not associated with the mobile IAB status.

In a third aspect, alone or in combination with one or more of the first and second aspects, process800includes receiving configuration information indicating the first threshold length of time.

In a fourth aspect, alone or in combination with one or more of the first through third aspects, performing the cell selection or reselection operation further comprises selecting the cell for camping based at least in part on the onboard status.

In a fifth aspect, alone or in combination with one or more of the first through fourth aspects, process800includes receiving information indicating a set of candidate cells, including the cell, that are potentially associated with the mobile IAB status.

In a sixth aspect, alone or in combination with one or more of the first through fifth aspects, process800includes camping on the cell for a second threshold length of time, wherein the onboard status is based at least in part on camping on the cell for the second threshold length of time.

In a seventh aspect, alone or in combination with one or more of the first through sixth aspects, the cell is a first cell, and performing the cell selection or reselection operation based at least in part on the onboard status further comprises reselecting a second cell associated with the mobile IAB status, and maintaining the onboard status with regard to the second cell.

In an eighth aspect, alone or in combination with one or more of the first through seventh aspects, the cell is a first cell, and performing the cell selection or reselection operation based at least in part on the onboard status further comprises reselecting a second cell associated with the mobile IAB status, and resetting a timer associated with the second threshold length of time.

In a ninth aspect, alone or in combination with one or more of the first through eighth aspects, performing the cell selection or reselection operation based at least in part on the onboard status further comprises prioritizing selection or reselection of cells associated with the mobile IAB status.

In a tenth aspect, alone or in combination with one or more of the first through ninth aspects, performing the cell selection or reselection operation based at least in part on the onboard status further comprises modifying a reselection timer or a hysteresis timer based at least in part on entering the onboard status.

In an eleventh aspect, alone or in combination with one or more of the first through tenth aspects, modifying the reselection timer is based at least in part on a mobility state parameter of the UE.

In a twelfth aspect, alone or in combination with one or more of the first through eleventh aspects, performing the cell selection or reselection operation based at least in part on the onboard status further comprises modifying a parameter used to determine a mobility state parameter of the UE based at least in part on the onboard status.

In a thirteenth aspect, alone or in combination with one or more of the first through twelfth aspects, performing the cell selection or reselection operation is based at least in part on a mobility state parameter, and reselection between cells associated with the mobile IAB status does not count toward a parameter used to determine the mobility state parameter.

In a fourteenth aspect, alone or in combination with one or more of the first through thirteenth aspects, performing the cell selection or reselection operation based at least in part on the onboard status further comprises performing cell measurements according to a baseline measurement configuration based at least in part on the onboard status.

In a fifteenth aspect, alone or in combination with one or more of the first through fourteenth aspects, performing the cell selection or reselection operation based at least in part on the onboard status further comprises performing cell measurements according to a measurement configuration corresponding to the onboard status.

In a sixteenth aspect, alone or in combination with one or more of the first through fifteenth aspects, process800includes receiving information indicating to use the measurement configuration corresponding to the onboard status.

In a seventeenth aspect, alone or in combination with one or more of the first through sixteenth aspects, the measurement configuration is specific to at least one of: cells associated with the mobile IAB status, a particular cell, or a particular frequency.

In an eighteenth aspect, alone or in combination with one or more of the first through seventeenth aspects, performing the cell selection or reselection operation based at least in part on the onboard status further comprises reselecting another cell not associated with the onboard status.

In a nineteenth aspect, alone or in combination with one or more of the first through eighteenth aspects, process800includes performing another cell selection or reselection operation deprioritizing cells associated with the mobile IAB status.

FIG.9is a diagram of an example apparatus900for wireless communication, in accordance with the present disclosure. The apparatus900may be a UE, or a UE may include the apparatus900. In some aspects, the apparatus900includes a reception component902, a transmission component904, and/or a communication manager906, which may be in communication with one another (for example, via one or more buses and/or one or more other components). In some aspects, the communication manager906is the communication manager140described in connection withFIG.1. As shown, the apparatus900may communicate with another apparatus908, such as a UE or a network node (such as a CU, a DU, an RU, an IAB node, or a base station), using the reception component902and the transmission component904.

The communication manager906may support operations of the reception component902and/or the transmission component904. For example, the communication manager906may receive information associated with configuring reception of communications by the reception component902and/or transmission of communications by the transmission component904. Additionally, or alternatively, the communication manager906may generate and/or provide control information to the reception component902and/or the transmission component904to control reception and/or transmission of communications.

The reception component902may receive an indication that a cell is associated with a mobile IAB status. The communication manager906may perform a cell selection or reselection operation based at least in part on an onboard status between the UE and the cell and based at least in part on the cell being associated with the mobile IAB status.

The communication manager906may detect the cell for a first threshold length of time, wherein the onboard status is based at least in part on detecting the cell for the first threshold length of time.

The reception component902may receive configuration information indicating the first threshold length of time.

The reception component902may receive information indicating a set of candidate cells, including the cell, that are potentially associated with the mobile IAB status.

The communication manager906may camp on the cell for a second threshold length of time, wherein the onboard status is based at least in part on camping on the cell for the second threshold length of time.

The reception component902may receive information indicating to use the measurement configuration corresponding to the onboard status.

The communication manager906may perform another cell selection or reselection operation deprioritizing cells associated with the mobile IAB status.

Aspect 1: A method of wireless communication performed by a user equipment (UE), comprising: receiving an indication that a cell is associated with a mobile integrated access and backhaul (IAB) status indicating that the cell is a mobile cell; and performing a cell selection or reselection operation based at least in part on an onboard status between the UE and the cell and based at least in part on the cell being associated with the mobile IAB status, wherein the onboard status indicates that the UE is onboard a moving entity.

Aspect 2: The method of Aspect 1, further comprising: detecting the cell for a first threshold length of time, wherein the onboard status is based at least in part on detecting the cell for the first threshold length of time.

Aspect 3: The method of Aspect 2, wherein the onboard status is based at least in part on detecting the cell for the first threshold length of time while the UE is camped on another cell not associated with the mobile IAB status.

Aspect 4: The method of Aspect 2, further comprising receiving configuration information indicating the first threshold length of time.

Aspect 5: The method of any of Aspects 1-4, wherein performing the cell selection or reselection operation further comprises selecting the cell for camping based at least in part on the onboard status.

Aspect 6: The method of any of Aspects 1-5, further comprising receiving information indicating a set of candidate cells, including the cell, that are potentially associated with the mobile IAB status.

Aspect 7: The method of any of Aspects 1-6, further comprising: camping on the cell for a second threshold length of time, wherein the onboard status is based at least in part on camping on the cell for the second threshold length of time.

Aspect 8: The method of Aspect 7, wherein the cell is a first cell, and wherein performing the cell selection or reselection operation based at least in part on the onboard status further comprises reselecting a second cell associated with the mobile IAB status; and maintaining the onboard status with regard to the second cell.

Aspect 9: The method of Aspect 7, wherein the cell is a first cell, and wherein performing the cell selection or reselection operation based at least in part on the onboard status further comprises reselecting a second cell associated with the mobile IAB status; and resetting a timer associated with the second threshold length of time.

Aspect 10: The method of any of Aspects 1-9, wherein performing the cell selection or reselection operation based at least in part on the onboard status further comprises prioritizing selection or reselection of cells associated with the mobile IAB status.

Aspect 11: The method of any of Aspects 1-10, wherein performing the cell selection or reselection operation based at least in part on the onboard status further comprises modifying a reselection timer or a hysteresis timer based at least in part on entering the onboard status.

Aspect 12: The method of Aspect 11, wherein modifying the reselection timer is based at least in part on a mobility state parameter of the UE.

Aspect 13: The method of any of Aspects 1-12, wherein performing the cell selection or reselection operation based at least in part on the onboard status further comprises modifying a parameter used to determine a mobility state parameter of the UE based at least in part on the onboard status.

Aspect 14: The method of any of Aspects 1-13, wherein performing the cell selection or reselection operation is based at least in part on a mobility state parameter, and wherein reselection between cells associated with the mobile IAB status does not count toward a parameter used to determine the mobility state parameter.

Aspect 15: The method of any of Aspects 1-14, wherein performing the cell selection or reselection operation based at least in part on the onboard status further comprises performing cell measurements according to a baseline measurement configuration based at least in part on the onboard status.

Aspect 16: The method of any of Aspects 1-15, wherein performing the cell selection or reselection operation based at least in part on the onboard status further comprises performing cell measurements according to a measurement configuration corresponding to the onboard status.

Aspect 17: The method of Aspect 16, further comprising receiving information indicating to use the measurement configuration corresponding to the onboard status.

Aspect 18: The method of Aspect 16, wherein the measurement configuration is specific to at least one of: cells associated with the mobile IAB status, a particular cell, or a particular frequency.

Aspect 19: The method of any of Aspects 1-18, wherein performing the cell selection or reselection operation based at least in part on the onboard status further comprises reselecting another cell not associated with the onboard status.

Aspect 20: The method of Aspect 19, further comprising performing another cell selection or reselection operation deprioritizing cells associated with the mobile IAB status.