Methods and apparatus for inter-RAT mobility and co-RAT mobility for mobile IAB

Abstract

The present disclosure relates to a 5G or 6G communication system supporting a higher data transmission rate, and provides a method in which a UE performs different RAT mIAB mobility in a communication network, the method comprising: acquiring, from a BS, an SIB including different RAT cell-related information, the inter-RAT cell related information includes at least one of: information about a frequency having one or more mobile IAB cells, or information about a list of one or more mobile IAB cells; and in a case where a heterogeneous RAT mobile IAB cell is detected, regarding a heterogeneous RAT frequency for the inter-RTA mobile IAB cell as having a highest priority for cell reselection.

Description

Technical Field

[0001] Embodiments of this disclosure provide various techniques related to different radio access technologies (RATs) for mobile integrated access backhaul (mIAB) and methods for mobility within the same RAT, such as methods for signaling mIAB auxiliary information for different RATs and within the same RAT in 3GPP 5G New Radio (NR) and NR-based relay networks. Background Technology

[0002] 5G mobile communication technology defines a wide frequency band, enabling high transmission rates and new services. It can be implemented not only in "sub-6GHz" bands such as 3.5GHz, but also in "above 6GHz" bands including 28GHz and 39GHz, known as millimeter waves (mmWave). Furthermore, the implementation of 6G mobile communication technology (referred to as "super 5G systems") in terahertz bands (such as the 95GHz to 3THz band) is being considered, aiming to achieve transmission rates 50 times higher than 5G mobile communication technology and ultra-low latency reduced to one-tenth of 5G mobile communication technology.

[0003] In the early stages of 5G mobile communication technology research and development, to support and meet the performance requirements of services related to enhanced mobile broadband (eMBB), ultra-reliable low-latency communication (URLLC), and massive machine-type communication (mMTC), related standardization work continued to advance. This involved: beamforming and massive MIMO technologies to mitigate mmWave path loss and improve transmission distance; parameter sets (e.g., operating multiple subcarrier spacings) to efficiently utilize mmWave resources and dynamically operate time slot formats; initial access technologies to support multi-beam transmission and broadband; definition and operation of the bandwidth portion (BWP); novel channel coding methods such as low-density parity-check (LDPC) codes for massive data transmission and polar codes for highly reliable transmission of control information; L2 preprocessing; and network slicing to provide dedicated networks for specific services.

[0004] Currently, in view of the services that 5G mobile communication technology needs to support, discussions are being conducted on optimizing and improving the performance of the initial 5G mobile communication technology. The physical layer standardization work involves: vehicle-to-everything (V2X) technology that assists autonomous vehicles in making driving decisions and improves user experience based on vehicle location and status information; New Radio Unlicensed Band (NR-U) technology aimed at adapting to various regulatory requirements of unlicensed frequency bands; NR UE energy-saving technology; non-terrestrial network (NTN) technology that provides communication services for areas not covered by terrestrial networks through direct UE-satellite communication; and positioning technology.

[0005] Meanwhile, in terms of air interface architecture and protocols, standardization efforts involve technologies such as: Industrial Internet of Things (IIoT) technologies to support new services through interoperability and integration with other industries; Integrated Access Backhaul (IAB) technologies to provide nodes for the expansion of network service areas by supporting wireless backhaul links and access links in a converged manner; mobility enhancement technologies that include conditional handover and Dual Active Protocol Stack (DAPS) handover; and two-step random access (2-step RACH for NR) technologies to simplify random access procedures. Standardization is also being advanced at the system architecture and service layer levels, involving: 5G baseline architectures (e.g., service-based architectures or service-based interfaces) for combining Network Functions Virtualization (NFV) and Software-Defined Networking (SDN) technologies, and Mobile Edge Computing (MEC) technologies for UE location-based reception services.

[0006] With the commercialization of 5G mobile communication systems, the number of connected devices will increase exponentially, making the enhancement of 5G functionality and performance, as well as the collaborative operation of access devices, inevitable requirements. To this end, the industry has planned new research directions, including: extended reality (XR) technology for efficiently supporting augmented reality (AR), virtual reality (VR), and mixed reality (MR); 5G performance enhancement and complexity reduction technologies utilizing artificial intelligence (AI) and machine learning (ML); AI service support and metaverse service support technologies; and drone communication technologies.

[0007] Furthermore, this development of 5G mobile communication systems will not only lay the foundation for the development of technologies such as: new waveforms for providing coverage in the terahertz band of 6G mobile communication technology; multi-antenna transmission technologies such as full-dimensional MIMO (FD-MIMO), array antennas, and massive MIMO; metamaterial-based lenses and antennas for improving terahertz signal coverage; high-dimensional spatial multiplexing technologies using orbital angular momentum (OAM) and reconfigurable smart surfaces (RIS); but also for the development of technologies such as: full-duplex technologies for improving the frequency efficiency of 6G mobile communication technology and optimizing system networks; AI-based communication technologies that utilize satellites and artificial intelligence (AI) from the design stage and internalize end-to-end AI support; and next-generation distributed computing technologies for utilizing ultra-high-performance communication and computing resources to achieve complex levels of service beyond the limitations of UE operational capabilities. Summary of the Invention

[0008] [Technical problems solved]

[0009] The purpose of this disclosure is to at least partially solve, eliminate, or mitigate at least one problem and / or defect existing in related technologies, such as at least one problem and / or defect described herein. The purpose of this disclosure is to provide at least one advantage over related technologies, such as at least one advantage described herein.

[0010] Other aspects, advantages and salient features of this disclosure will become apparent to those skilled in the art upon reading the following detailed description in conjunction with the accompanying drawings.

[0011] One aspect of this disclosure provides a method for transmitting different-RAT mIAB auxiliary information or same-RAT mIAB auxiliary information from the network to the network UE in a communication network to achieve mIAB different-RAT or same-RAT mobility.

[0012] The method may include configuring RAT mIAB cell auxiliary information for the UE in an NR mIAB cell when the UE is released to RRC idle mode or RRC inactive mode. The method may also include configuring different RAT mIAB cell auxiliary information for the UE in an E-UTRA cell when the UE is released to RRC idle mode or RRC inactive mode.

[0013] Another aspect of this disclosure provides a communication network that sends different-RAT mIAB auxiliary information or same-RAT mIAB auxiliary information to UEs within the network to enable mIAB different-RAT or same-RAT mobility. Attached Figure Description

[0014] Figure 1 The diagram shows a two-hop IAB network, taken from 3GPP TR 38.874 "Integrated Access and Backhaul Study" V16.0.0 (December 2018). Figure 2 The process of NR to E-UTRAN mobility is illustrated; Figure 3 This indicates the connectivity mode and mobility. Figure 4 This illustrates the RRC release process; Figure 5 This illustrates the RRC connection release process; Figure 6 This diagram illustrates a deployment scenario where a train carrying macro cells and mIAB cells travels within a defined area of ​​macro cell deployment. Figure 7 This shows the eNB that transmits auxiliary information for different RAT mIAB cells; Figure 8After indicating the existence of a mIAB cell, the gNB chooses to broadcast mIAB cell auxiliary information; Figure 9A shows the release of the UE and the configuration of mIAB different RAT priority information or mIAB cell auxiliary information for use in the same RAT and different RAT scenarios. Figure 9B shows how to release the UE and configure it with mIAB different RAT priority information or mIAB cell auxiliary information for use in the same RAT and different RAT scenarios. Figure 10 This example demonstrates how to configure mIAB priority information or mIAB cell auxiliary information for a UE. Figure 11 This example demonstrates how to configure mIAB priority information or mIAB cell auxiliary information for a UE. Figure 12 A flowchart illustrating a method for moving IAB-RAT mobility according to an embodiment of the present disclosure; Figure 13 A flowchart is shown for a mobile IAB-RAT mobility method according to an embodiment of the present disclosure; Figure 14 The structure of a UE according to an embodiment of this disclosure is shown; Figure 15 The structure of a BS according to an embodiment of this disclosure is shown. Detailed Implementation

[0015] In one embodiment, a method for a UE in a wireless communication system is provided, the method comprising: obtaining a system information block (SIB) from a BS (base station), the SIB including information related to different RAT cells, wherein the information related to different RAT cells includes at least one of the following: information about frequencies having one or more mobile IAB cells, or information about a list of one or more mobile IAB cells; and, upon detecting a different RAT mobile IAB cell, treating the different RAT frequency used for the different RAT mobile IAB cell as having the highest priority for cell reselection.

[0016] In one embodiment, the information regarding the frequency of one or more mobile IAB cells indicates that the one or more mobile IAB cells are deployed on the different RAT frequency.

[0017] In one embodiment, the SIB is a type 24 SIB.

[0018] In one embodiment, the method further includes: obtaining SIB 1, which includes information indicating that the different RAT cell is a mobile IAB cell; and identifying the different RAT mobile IAB cell based on the information included in the SIB 1.

[0019] In one embodiment, the BS is an E-UTRAN (Evolved Universal Terrestrial Radio Access Network) cell, the different RAT mobile IAB cell is an NR (New Radio) mobile IAB cell, and the different RAT frequency is an NR frequency.

[0020] In one embodiment, the method further includes: receiving an RRC release message containing auxiliary information of a different RAT mobile IAB cell from the BS; and redirecting to the different RAT mobile IAB cell based on the auxiliary information of the different RAT mobile IAB cell included in the RRC release message.

[0021] In one embodiment, a method of a BS in a wireless communication system is provided, the method comprising: broadcasting an SIB containing information related to an inter-RAT cell, wherein the inter-RAT cell information includes at least one of the following: information about frequencies having one or more mobile IAB cells, or information about a list of one or more mobile IAB cells; and, in the event of an inter-RAT mobile IAB cell being detected, the inter-RAT frequency for the inter-RAT mobile IAB cell is considered to have the highest priority for cell reselection.

[0022] In one embodiment, a UE (User Equipment) is provided in a wireless communication system, the UE comprising: a memory storing one or more instructions; and at least one processor configured to execute the one or more instructions to: obtain a System Information Block (SIB) from a base station (BS), the SIB including Different Radio Access Technology (RAT) cell-related information, wherein the different RAT cell-related information includes at least one of the following: information about frequencies having one or more Mobile Integrated Access Backhaul (IAB) cells, or information about a list of one or more mobile IAB cells; and upon detecting a different RAT mobile IAB cell, treating the different RAT frequencies used for the different RAT mobile IAB cell as having the highest priority for cell reselection.

[0023] In one embodiment, the information regarding the frequency of one or more mobile IAB cells indicates that the one or more mobile IAB cells are deployed on the different RAT frequency.

[0024] In one embodiment, the SIB is a type 24 SIB.

[0025] In one embodiment, the at least one processor is further configured to execute the one or more instructions to: acquire SIB 1, which includes information indicating that the different RAT cell is a mobile IAB cell; and identify the different RAT mobile IAB cell based on the information included in the SIB 1.

[0026] In one embodiment, the BS is an Evolved Universal Terrestrial Radio Access Network (E-UTRAN) cell, the different RAT IAB cell is a New Radio Interface (NR) Mobile IAB cell, and the different RAT frequency is an NR frequency.

[0027] In one embodiment, the at least one processor is further configured to execute the one or more instructions to: receive a Radio Resource Control (RRC) release message from the BS, the RRC release message including inter-RAT Mobile IAB cell assistance information; and redirect to the inter-RAT Mobile IAB cell based on the inter-RAT Mobile IAB cell assistance information included in the RRC release message.

[0028] In one embodiment, a BS (Base Station) is provided in a wireless communication system, the BS comprising: A memory storing one or more instructions; and at least one processor configured to execute the one or more instructions to: broadcast a system information block (SIB) containing information related to different Radio Access Technology (RAT) cells, wherein the different RAT cell information includes at least one of the following: information about frequencies having one or more Mobile Integrated Access Backhaul (IAB) cells, or information about a list of one or more mobile IAB cells; and wherein, in the event of a different RAT mobile IAB cell being detected, the different RAT frequency for the different RAT mobile IAB cell is considered to have the highest priority for cell reselection.

[0029] In one embodiment, the information regarding the frequency of one or more mobile IAB cells indicates that the one or more mobile IAB cells are deployed on the different RAT frequency.

[0030] The following description of embodiments of this disclosure, taken in conjunction with the accompanying drawings, is intended to help in a comprehensive understanding of the disclosure as defined by the claims. Various specific details included in the description are for illustrative purposes only and should be considered exemplary. Therefore, those skilled in the art will recognize that various modifications and variations can be made to the embodiments described herein.

[0031] The following embodiments are applicable to 3GPP 5G and use relevant terminology. However, those skilled in the art should understand that the technology disclosed in this disclosure is not limited to the above embodiments or 3GPP 5G, and can be applied to any suitable communication system or standard, such as one or more existing and / or next-generation wireless communication systems or standards. Those skilled in the art should understand that the technology disclosed in this disclosure can be applied to any existing or future version of 3GPP 5G NR and other relevant standards.

[0032] For example, the functions and other characteristics of the various network entities disclosed in this disclosure can be applied to corresponding or equivalent entities / characteristics in other communication systems or standards. Corresponding or equivalent entities / characteristics refer to entities / characteristics that perform the same or similar functions or operations in the network. For example, the functions of the IAB node in the following example can be applied to other suitable types of entities that perform network node functions.

[0033] Those skilled in the art will understand that this disclosure is not limited to the specific embodiments disclosed herein, such as: The technologies disclosed in this public announcement are not limited to 3GPP 5G; One or more entities in the embodiments disclosed herein may be replaced by one or more alternative entities that perform equivalent or corresponding functions or processes; One or more messages in the embodiments disclosed herein may be replaced by one or more alternative messages, signals or other information carriers that transmit equivalent or corresponding information. One or more additional elements, entities, and / or messages may be added to the embodiments disclosed herein; In some embodiments, one or more non-essential elements, entities, and / or messages may be omitted; The functionality, process, or operation of an entity in one example can be shared by two or more independent entities in an alternative example; The functions, processes, or operations of two or more independent entities in one embodiment may be performed by a single entity in an alternative embodiment; The information carried by a message in one example can be carried by two or more independent messages in an alternative example; The information carried by two or more independent messages in one example can be carried by a single message in an alternative example; Where feasible, the execution order of operations can be adjusted in alternative examples; Information transmission between network entities is not limited to the specific form, type, and / or order of messages described in the embodiments disclosed herein.

[0034] To meet the demands of ultra-high data rates, the 3GPP 5G NR standard uses a relatively high range of communication frequencies from 30GHz to 300GHz, corresponding to the millimeter-wave wavelength range (mmWave communication). This provides mmWave communication with a large available bandwidth and high transmission rates. However, millimeter-wave communication suffers from problems including high signal path loss and weak penetration, resulting in relatively short transmission distances. This necessitates higher base station deployment density.

[0035] Embodiments of this disclosure provide a network or wireless communication system including a first network entity and a second network entity as described in any of the examples, embodiments, aspects and / or claims disclosed herein.

[0036] Embodiments of this disclosure provide a computer program, including instructions that, when executed by a computer or processor, cause the computer or processor to perform the methods described according to any of the examples, embodiments, aspects and / or claims disclosed herein.

[0037] Embodiments of this disclosure provide a computer or processor-readable data carrier having a computer program according to the foregoing examples stored thereon.

[0038] This disclosure also relates to additional methods for transmitting different or the same RAT mIAB auxiliary information in mIAB idle / inactive modes for signaling.

[0039] In the following description, exemplary embodiments may be applied to eNB, gNB, en-gNB, NG-RAN, or NG-eNB. For example, in embodiments, this disclosure is applicable to eNB, but may also be applicable to NG-eNB (eNB connected to EPC, NG-eNB connected to 5GC). In embodiments, methods specifically applicable to NG-eNB, en-gNB, gNB, or NG-RAN may also be provided.

[0040] Integrated Access Backhaul (IAB)

[0041] In the 3GPP 5G New Radio (NR) framework, Integrated Access Backhaul (IAB) is a technology that replaces fiber optic backhaul networks with wireless backhaul. An IAB network consists of IAB nodes whose radio resources are shared between the wireless backhaul link and the access link. This configuration allows nodes to be installed without providing fiber optic data connections, enabling quick and easy network coverage in locations where such data connections are unavailable. Because IAB nodes have limited coverage, backhaul networks typically employ multi-hop networks, requiring backhaul services to traverse multiple IAB nodes.

[0042] Figure 1The two-hop IAB network, defined in 3GPP 5G NR Rel-16, is further enhanced in Rel-17. 3GPP 5G Rel-16 first introduced IAB features, and Rel-17 completes the enhancements and has been finalized. Currently, Rel-18 development is underway to develop and improve IAB-related features compared to previous versions, with the most crucial being the mobility of IAB nodes. Previous versions assumed fixed deployment of IAB nodes.

[0043] Mobile IAB

[0044] Mobile IAB is a research project in 3GPP Release 18, with the core focus on enhancing IAB technology to support mobile IAB. The deployment goal of Mobile IAB is to provide communication connectivity for trains, buses, and other vehicles through IAB Distributed Units (DUs). Mobile IAB does not support dual connectivity (DC) options (i.e., Evolved Universal Terrestrial Radio Access (E-UTRA) NR(EN)-DC or New Radio (NR)-DC). Its core function is to provide robust mobility support. The research project description mentions the following enhancement directions [RP-222671, Mobile IAB for NR (Integrated Access Backhaul), Qualcomm, RAN#97, September 2022]: Define the migration / topology adaptation process to support IAB node mobility, including the migration of the entire mobile IAB node across donor nodes (full migration) [RAN3, RAN2]: Mobile IAB nodes can connect to fixed (intermediate) IAB nodes. Specific optimizations for scenarios where mobile IAB nodes connect to fixed (intermediate) IAB nodes or directly to IAB donor DUs are given lower priority. Mobility optimization for dual-connectivity IAB nodes is given low priority.

[0045] Enhance the mobility of IAB nodes and their served user equipment (UEs), including aspects related to group mobility. No optimization for handover objectives targeting surrounding UEs is studied [RAN3, RAN2].

[0046] Mitigating interference caused by IAB node movement, including avoiding potential conflicts between reference and control signals (e.g., PCI, Random Access Channel (RACH)) [RAN3, RAN2].

[0047] Long Term Evolution (LTE) heterogeneous RAT mobility

[0048] Connection mode

[0049] The handover from NR to the Evolved Universal Telecommunications System Terrestrial Radio Access Network (E-UTRAN) is performed via the Radio Resource Control (RRC) message MobilityFromNRCommand. The RRC message MobilityFromNRCommand contains the handover command based on the specific RAT to which the UE needs to perform the mobility handover. In the case of handover to E-UTRAN, this message contains the E-UTRAN's RRCConnectionReconfiguration message. See [link to details] for further information. Figure 2 .

[0050] A cross-core network (CN) mobility procedure is also triggered when performing so-called cross-system mobility (also sometimes called cross-system mobility). This occurs when moving between two cells belonging to different core networks. An example of this is when moving from the E-UTRAN Evolved Packet Core Network (EPC) to the E-UTRAN 5G Core Network (5GC) or vice versa. In this case, mobility is triggered via the RRCConnectionReconfiguration message. See [example example]. Figure 3 When a UE in E-UTRAN is running in 5GC, the UE uses NR PDCP and SDAP instead of LTE PDCP (i.e., without SDAP).

[0051] Idle mode

[0052] Both LTE and NR support inter-RAT cell reselection in RRC idle mode and RRC inactive mode. In both LTE and NR, there are measurement conditions that support inter-RAT cell reselection.

[0053] If the frequency has a higher priority than the current serving frequency, the UE should always perform measurements on that different RAT frequency. If the priority of the different RAT frequency is equal to or lower than that of the serving cell signal strength, the UE should perform measurements only if the serving cell signal strength meets certain specific thresholds; otherwise, the UE should perform measurements on the different RAT frequency.

[0054] There are also rules for cell reselection to a cell in a different RAT. To select a higher-priority NR frequency, the cell signal strength must remain above a configured threshold for the entire TreselectionRAT cell reselection interval. Reselection of cells with the same priority is based on the order of reselection of cells on the same frequency. Finally, the triggering condition for cell reselection to a cell in a lower-priority frequency in a different RAT is that, during the TreselectionRAT interval, the serving cell signal quality is below a threshold, and the signal strength of adjacent cells remains above a threshold. In all cases, to remain on a cell, the cell must meet the cell selection S criterion.

[0055] In NR, if a UE selects a different RAT cell in RRC inactive mode (RRC_INACTIVE), the UE will switch from RRC_INACTIVE to RRC_IDLE mode.

[0056] In some cell reselection scenarios, the UE is required to remain in the current serving cell for at least 1 second before it can reselect to a new cell.

[0057] In idle mode for different RAT mobility, the following system information will be broadcast: The NR Cell Broadcast System Information Block (SIB) 5 provides cell reselection parameters and information about different RAT E-UTRAN frequencies. The information provided in this SIB includes, for example: List of E-UTRA frequencies and carrier frequencies for E-UTRA cells; T-ReselectionEUTRA; Cell reselection parameters, such as priority, selection threshold, etc., and List of residential communities; SIB24 is broadcast in E-UTRAN cells to perform inter-RAT measurements and cell reselection for NR cells. This SIB provides crucial information about NR cells needed for measurement, such as: List of carrier frequencies for NR frequencies; Cell reselection parameters, such as priority and selection threshold; T-ReselectionNR is the cell reselection timer value. If the UE is camped on an E-UTRA cell, in order to reselect to an NR cell, the signal quality value (Squal) must be higher than ThreshX,HighQ for a longer duration of T-ReselectionNR. The timer value is 0, 1, 2...7 seconds; NR-specific parameters required for detecting and measuring NR cells: SMTC SSB information, such as SSB SCS, SSB location, and SSB measurement timing configuration (SMTC). List of residential communities.

[0058] RRC Release

[0059] NR's RRC release

[0060] One way to enter RRC idle mode or RRC inactive mode is through a network-initiated RRC release procedure. This procedure is initiated when the UE receives an RRCRelease message from the gNB. See details... Figure 4 .

[0061] The RRCRelease message sent by the gNB may be triggered by the gNB itself or by the Access and Mobility Management Function (AMF). This can be triggered, for example, by any of the following reasons: Load balancing; Redirect (applicable to RRC idle mode and RRC inactive mode) to other frequencies or RATs; UE context release triggered by AMF (CN), for example, due to no downlink (DL) or uplink (UL) data in the buffer; A suspend indication is sent to the UE to switch to RRC inactive mode; When the UE recovers from RRC inactive mode to RRC connected mode, obtaining the UE context fails.

[0062] An RRC release message may contain, for example, the following information elements: redirectedCarrierInfo: Information about the carrier to which the carrier needs to be redirected; it can be a frequency of the same RAT or a different RAT. cellReselectionPriorities: Cell reselection priorities—can be specifically configured for the UE in the RRCrease message; suspendConfig: Used for configuring RRC inactive mode; deprioritisationReq; waitTime; measIdleConfig: This is the measurement configuration for idle mode, used to measure and store measurement information that needs to be reported to the network when reconnecting; sdtConfig: Configuration for short data transmission (allows the UE to send typically small amounts of data in RRC inactive mode); srs-PosRRC-Inactive: SRS configuration for RRC inactive mode positioning.

[0063] Includes the following potential timers: - waitTime (T302): A timer that prevents the UE from attempting to access the network; - T320: How long will the cell's reselection priority take before activation? - T380: RAN Notification Area Update based on timer.

[0064] LTE RRC release

[0065] RRC connection release is a procedure used to send the UE to RRC idle mode or RRC idle mode with pending connection. See details for further information. Figure 5 .

[0066] In RRCConnectionRelease (E-UTRAN / LTE version), the following signaling can be sent: Reason for release: load balancing TAU required Other cs-FallbackHighPriority rrc-Suspend RedirectedCarrierInfo: Includes different RAT frequencies, such as EUTRA, GERAN, utra, cdma2000, NR. idleModeMobilityControlInfo: Frequency priority list, used to indicate different carrier frequencies and their cell reselection priorities for different RATs. T320 is used to indicate the duration of activation of the frequency priority list. cellInfoList Provides reselection information for one or more cells on different RAT frequencies, including cell ID, carrier frequency, and system information for cells on other RATs. MeasIdleConfig It conveys information about the measurements to be performed in idle mode, enabling faster carrier aggregation setup; Alternative frequency priority: Instruct the UE to apply alternative cell reselection priority Release idle mode measurement configuration: Instructs the UE to release the configured idle / inactive mode measurement configuration (if configured) for early CA establishment (CA / DC enhancement).

[0067] The first issue with mIAB is the large coverage area of ​​macro cells and the small coverage area of ​​mIAB cells. Because mIAB cells are mobile and their movement can be unpredictable, it may not always be possible to broadcast the correct mIAB information at the appropriate time. This is especially important because system information (particularly cell reselection parameters) typically doesn't change over long periods. Therefore, it may be necessary to provide UEs with more tools to send mIAB cell assistance information in a more specialized way. Deployment examples can be found in [link to deployment example]. Figure 6 The miAB cell passes through only a small portion of the larger macro cell.

[0068] The second issue regarding mIAB is the very close relationship between E-UTRAN / LTE / 4G and NR / 5G, as mobility between them is designed to be efficient and nearly seamless compared to other heterogeneous RATs. If efficient idle-mode mobility from E-UTRAN to NRmIAB cells cannot be achieved, the value of mIAB could be significantly diminished, since most practical deployments heavily rely on both E-UTRAN and NR cells.

[0069] The above information is provided for background information purposes only to aid in understanding this disclosure. It has not been determined and is not claimed whether any of the above content can be considered prior art.

[0070] mIAB's different RAT idle mode and inactive mode mobility

[0071] To enable the network to fully utilize the value of mIAB cells, this disclosure supports performing inter-RAT cell reselection from E-UTRAN (non-mIAB, since there are no IAB E-UTRAN cells) to mIAB NR.

[0072] To enable the UE to efficiently perform inter-RAT cell reselection from E-UTRAN to NR mIAB cells, the network can send inter-RAT mIAB auxiliary information about potential mIAB cells or frequencies in the E-UTRAN nodes. See specific examples. Figure 7 .

[0073] The inter-RAT mIAB auxiliary information about NR mIAB cells transmitted on the E-UTRAN node may include, for example, the following fields: The existence of mIAB cells in terms of frequency: It can be a flag bit to indicate the presence of a mIAB cell on this frequency, and if a mIAB cell is detected, the UE can preferentially select this frequency; List of mIAB cells; TreselectionRAT-mIAB, specifically for mIAB. For example, it can be set to a duration shorter than TreselectionNR to allow faster reselection from EUTRA cells to NR mIAB cells. It can be used for all mIAB cells or dedicated to specific frequencies where mIAB cells exist. mIAB cell-specific reselection threshold: Potential examples include q-RxLevMin (the minimum Rx level for a cell to satisfy the S criterion), threshX-High (a threshold for high-priority frequencies), threshX-Low (a threshold for low-priority frequencies), and threshX-Q. These thresholds are only applicable to mIAB cells at this frequency.

[0074] The aforementioned inter-RAT mIAB auxiliary information fields can be sent via System Information Blocks (SIBs), with SystemInformationBlockType24 being the most suitable SIB. Some inter-RAT mIAB auxiliary information fields (such as the mIAB cell list and the presence of mIAB cells on a given frequency) can be sent by frequency. Some fields (such as the mIAB-specific TreselectionRAT) can be sent for the entire inter-RAT cell reselection parameters. They can also be sent via release messages. See Specification Example 1 below for a specific specification example.

[0075] Because the relevant area for implementing inter-RAT idle mode mobility may be significantly smaller than the size of a mIAB cell, additional information can be sent to indicate when and where inter-RAT mIAB auxiliary information should be applied, or when a mIAB cell should be detected. This information can be regional or temporal. For regional information, it can be represented as a set of geographic coordinates and a radius. For temporal information, it can be a single point in time or a time window. Time and regional information can be sent independently or together.

[0076] In one aspect of this disclosure, when performing a different RAT reselection to a mIAB cell, the UE is not required to comply with the restriction of "waiting 1 second before reselecting to another cell".

[0077] In one aspect of this disclosure, if there are multiple cells that meet the inter-RAT cell reselection criteria, and only one of them is a mIAB cell, then the UE may select the mIAB cell. This means that in inter-RAT cell reselection, the mIAB cell may have higher priority.

[0078] For the method by which the UE identifies a different RAT cell as a mIAB cell, it can either use, for example, the different RAT mIAB auxiliary information sent in SIB24, or the UE can determine the auxiliary information based on the indication of a specific neighboring cell in SIB1.

[0079] An example of how to broadcast potentially needed inter-RAT mIAB auxiliary information is as follows: When there are no nearby mIAB cells, the network may not broadcast specific system-level inter-RAT mIAB auxiliary information (e.g., in SIB24). When the network learns that a mIAB cell may be approaching, it can begin broadcasting system-level inter-RAT mIAB auxiliary information (e.g., using SIB24). Initiating the broadcast of system-level inter-RAT mIAB auxiliary information can be triggered by a neighboring cell or via OAM. If triggered by a neighboring cell, this can be achieved through messages on the Xn interface, using messages such as the NG-RAN NODE CONFIGURATION UPDATE or other new messages. See [link to specific example] for details. Figure 8 .

[0080] Release configuration mIAB cell auxiliary information via RRC

[0081] As mentioned above regarding some issues with mIAB, broadcasting appropriate mIAB cell auxiliary information may be difficult.

[0082] In one aspect of this disclosure, when a UE is released to RRC idle mode or RRC inactive mode, it can be configured with RAT mIAB cell assistance information in an NRmIAB cell. The UE can configure RAT mIAB cell assistance information from the NR gNB. The UE can configure the RAT mIAB cell assistance information, for example, in an RRC message (such as an RRC release message). Based on this RAT mIAB cell assistance information, the UE can subsequently access the NR mIAB cell. A general schematic diagram can be seen in Figure 9, and a specification example can be seen in Specification Example 3 below.

[0083] In one aspect of this disclosure, when a UE is released to RRC idle mode or RRC inactive mode, it can be configured with inter-RAT mIAB cell assistance information in an E-UTRA cell. The UE can configure inter-RAT mIAB cell assistance information from an E-UTRAN eNB. The UE can configure the inter-RAT mIAB cell assistance information in an RRC message (such as an RRCConnectionRelease message). See Figure 9 for details, and specification example 2 below.

[0084] For example, the UE can be redirected to the mIAB cell via auxiliary information of a different RAT mIAB cell or the same RAT mIAB cell in the RRCConnectionRelease message. This method may be more reasonable if there is no X2 or Xn interface (i.e., inter-node interface) between the mIAB cell and the NR / E-UTRA cell.

[0085] In one aspect of this disclosure, when a UE is "redirected" to another frequency and / or a different RAT, mIAB cell assistance information can be configured for it. In a redirection scenario, there may only be one frequency, and the UE subsequently performs cell selection based on this information. The redirection configuration may also include the PCI of the mIAB cell, or a flag indicating that the UE should preferentially select the mIAB cell during redirection (i.e., when performing cell selection).

[0086] In one aspect of this disclosure, when configuring a dedicated priority for a UE, mIAB cell auxiliary information can be configured simultaneously for it. The mIAB cell auxiliary information can be either different RAT mIAB cell auxiliary information or the same RAT mIAB cell auxiliary information. In a further aspect of configuring dedicated mIAB cell auxiliary information for a UE via an RRC release message, the T320 timer can be set to a shorter duration. The T320 timer is used to manage the usage duration of the dedicated priority. In mIAB, due to mIAB cell mobility, maintaining such mIAB cell auxiliary information for an extended period may adversely affect network performance because the information may become outdated. In one aspect, an independent timer can be introduced for different RAT mIAB cell auxiliary information. This timer allows the network to configure significantly shorter or potentially longer durations for the mIAB cell auxiliary information.

[0087] The different or same RAT mIAB cell auxiliary information in the RRCConnectionRelease message can be part of the following configuration: -RedirectionInfo (E-UTRAN version) / RedirectedCarrierInfo (NR version); - Idle mode control information (E-UTRAN) — See Example 2 below for a specific example; - CellReselectionPriorities(NR).

[0088] For gNBs or eNBs that configure the same RAT mIAB cell auxiliary information for the UE, please refer to the application examples of the above aspects of this disclosure. Figure 10 In this example, the gNB can first configure the UE to measure mIAB cells in connected mode. This may be for the eventual handover to a specific mIAB cell. After reporting some measurement results, the UE may have no further DL or UL services, thus triggering the network to release the UE to RRC idle mode or RRC inactive mode. Since the gNB has received measurement results indicating the presence of mIAB cells, the gNB can configure mIAB cell auxiliary information for the UE.

[0089] In one example, the gNB can receive the mIAB onboard indication in RRC connected mode. Afterwards, the network can configure mIAB priority information or RAT mIAB cell auxiliary information for the UE. For example, this can be configured for the UE in the RRC release message. The UE onboard indication is a concept introduced in the 3GPP Rel-18 Mobile IAB workshop. See [link to workshop for details] for more information. Figure 11 .

[0090] In one aspect of this disclosure, the UE may send an indication to the network indicating its desire to access a mIAB cell. This can be achieved via a mIAB-PreferenceIndication message. This message can be configured by the network via otherConfig (which can be sent via an RRC reconfiguration message), and then UE assistance information (RRC message UEAssistanceInformation) is sent in the UL.

[0091] Even non-mIAB gNBs can determine, based on factors such as UE location and historical trajectory, that a UE is likely to need to configure mIAB cell auxiliary information.

[0092] When a UE is released from RRC connected mode to RRC idle mode or RRC inactive mode, the UE may need to perform cell selection (rather than cell reselection) first. In one aspect of this disclosure, when the UE is released and performs cell selection, the UE can preferentially select any mIAB cell in the cell selection algorithm. This is crucial because cell selection algorithms typically do not involve priority—they only consider whether the cell is suitable for camping.

[0093] In one aspect, if a UE is redirected to or connected to a mIAB cell due to release, and the UE is prohibited from accessing the mIAB cell for a certain time interval (e.g., waitTime, as measured by the prohibition timer T302), then the UE can apply that time interval (waitTime) to all mIAB cells. This may help alleviate overload situations, such as when a group of mIAB cells may be overloaded due to active mobility (handover in RRC connected mode) and idle mode mobility released via RRC, as well as idle mode mobility based on broadcast configuration (i.e., cell reselection).

[0094] Considering the time interval applicable to the mIAB cell measured by the T302 timer, this rule can also be executed / applied when the UE camps and subsequently connects to the mIAB cell (i.e., it does not need to be triggered by an RRC release message). This prohibition rule can also be applied to both receiving an RRC release message and receiving an RRC rejection message.

[0095] Standard Example

[0096] Example 1

[0097] The revised specifications are marked in bold. 3GPP 36.331 version 17 V17.5.0, June 2023.

[0098] SystemInformationBlockType24 [Table 1]

[0099] IE SystemInformationBlockType24 It contains information related to inter-RAT cell reselection (i.e., information about the NR frequency used for cell reselection and NR neighboring cells), and can also be used for NR idle / inactive mode measurements. This IE includes general cell reselection parameters for the frequency.

[0100] [Table 1]

[0101] SystemInformationBlockType24 Information Element

[0102] Example 2

[0103] The revised specifications are marked in bold.

[0104] Based on version 7 V17.5.0 (36.331), June 2023.

[0105] RRCConnectionRelease [Table 2]

[0106] RRCConnectionRelease The message is used to command the release of the RRC connection or to complete the UP-EDT process.

[0107] - Signaling radio bearer: SRB1

[0108] - RLC-SAP: AM

[0109] - Logical Channel: DCCH

[0110] - Direction: E-UTRAN to UE

[0111] [Table 2]

[0112] RRCConnectionRelease message

[0113] Example 3

[0114] The revised specifications are marked in bold.

[0115] Version 38.331 17 V17.5.0, June 2023.

[0116] RRCRelease message [Table 3]

[0117] RRCRelease The message is used to command the release of an RRC connection or to suspend an RRC connection.

[0118] Signaling radio bearer: SRB1

[0119] RLC-SAP: AM

[0120] Logical Channel: DCCHA

[0121] Direction: Network to UE.

[0122] [Table 3]

[0123] RRCRelease information

[0124] Figure 12 This is a flowchart of a method 1200 for different RAT mobility for mobile IAB according to an embodiment of the present disclosure.

[0125] Reference Figure 12 In S1210, according to an embodiment, UE 1400 obtains an SIB containing information about different RAT cells from BS (Base Station). The information about different RAT cells includes at least one of the following: information about frequencies having one or more mIAB cells, or information about a list of one or more mobile IAB cells. The information about frequencies having one or more mobile IAB cells indicates that one or more mobile IAB cells are deployed on the different RAT frequency.

[0126] In S1220, if a different RAT mobile IAB cell is detected, UE 1400 will consider the different RAT frequency used for that different RAT mobile IAB cell as having the highest priority for cell reselection.

[0127] Figure 13 This is a flowchart of a method 1300 for different RAT mobility for mobile IAB according to an embodiment of the present disclosure.

[0128] Reference Figure 13 In S1310, according to an embodiment, network entity 1500 may broadcast an SIB containing information about different RAT cells, wherein the information about different RAT cells includes at least one of the following: information about frequencies having one or more mobile IAB cells, or information about a list of one or more mobile IAB cells. The information about frequencies having one or more mobile IAB cells indicates that one or more mobile IAB cells are deployed on the different RAT frequency.

[0129] In S1320, when a different RAT mobile IAB cell is detected, the different RAT frequency used for that different RAT mobile IAB cell is taken as having the highest priority for cell reselection.

[0130] Figure 14 This is a block diagram of a UE 1400 according to another embodiment of the present disclosure.

[0131] Reference Figure 14 UE 1400 may include a processor 1410, a transceiver 1420, and a memory 1430. However, not all illustrated components are necessary. UE 1400 may be derived from... Figure 14 The implementation may use more or fewer components as shown. Furthermore, according to another embodiment, the processor 1410, transceiver 1420, and memory 1430 may be implemented as a single chip.

[0132] The following is a detailed description of the above components: Processor 1410 may include one or more processors or other processing devices for controlling the proposed functions, processes, and / or methods. The operation of UE 1400 described above in this disclosure may be implemented by processor 1410.

[0133] At least one processor 1410 may include various processing circuitry and / or multiple processors. For example, as used herein (including the claims), the term "processor" may include various processing circuitry, including at least one processor, wherein one or more of the at least one processor may be individually and / or distributedly configured to perform the various functions described herein. As used herein, when describing "processor," "at least one processor," and "one or more processors" as configured to perform multiple functions, these terms cover scenarios (e.g., but not limited to): one processor performing some of the functions, another one or more processors performing other of the functions, and a single processor performing all of the functions. Furthermore, at least one processor may include a combination of multiple processors to perform the various described / disclosed functions in a distributed manner. At least one processor may execute program instructions to implement or perform the various functions.

[0134] Transceiver 1420 may include an RF transmitter for up-converting and amplifying the transmitted signal, and an RF receiver for down-converting the received signal. However, according to another embodiment, transceiver 1420 may be implemented with more or fewer components than those illustrated.

[0135] Transceiver 1420 can be connected to processor 1410 and send and / or receive signals, which may include control information and data. Furthermore, transceiver 1420 can receive signals via a wireless channel and output signals to processor 1410; transceiver 1420 can also transmit signals output by processor 1410 via a wireless channel.

[0136] Memory 1430 may store control information or data contained in signals acquired by UE 1400. Memory 1430 may be connected to processor 1410 and store at least one instruction, protocol, or parameter for the proposed function, process, and / or method. Memory 1430 may include read-only memory (ROM) and / or random access memory (RAM) and / or hard disk and / or CD-ROM and / or digital versatile optical disc (DVD) and / or other storage devices.

[0137] Figure 15 This is a block diagram of a network entity 1500 according to an embodiment of the present disclosure.

[0138] Network entity 1500 can be used to implement the DU, CU-UP, CU-CP, gNB, eNB, source base station, target base station, source DU, source CU-UP, target DU, target CU-UP, target CU-CP, main base station, auxiliary base station, OAM, UDM, AMF, SMF or UPF, etc. disclosed herein.

[0139] Reference Figure 15 Network entity 1500 may include at least one processor 1510, transceiver 1520, and memory 1530. However, not all illustrated components are necessary. Network entity 1500 may be composed of... Figure 15 The implementation may involve more or fewer components as shown. Furthermore, according to another embodiment, at least one processor 1510, transceiver 1520, and memory 1530 may be implemented as a single chip.

[0140] The following is a detailed description of the above components: At least one processor 1510 may include one or more processors or other processing devices for controlling the proposed functions, processes, and / or methods. The operation of the network entity 1500 described above in this disclosure may be implemented by processor 1510. Processor 1510 may execute one or more instructions stored in memory 1530 to implement the above operations.

[0141] At least one processor 1510 may include various processing circuitry and / or multiple processors. For example, as used herein (including the claims), the term "processor" may include various processing circuitry, including at least one processor, wherein one or more of the at least one processor may be configured individually and / or distributed to perform the various functions described herein. As used herein, when describing "processor," "at least one processor," and "one or more processors" as configured to perform multiple functions, these terms cover scenarios (e.g., but not limited to): one processor performing some of the functions, another one or more processors performing other of the functions, and a single processor performing all of the functions. Furthermore, at least one processor may include a combination of multiple processors to perform the various described / disclosed functions in a distributed manner. At least one processor may execute program instructions to implement or perform various functions.

[0142] Transceiver 1520 may include an RF transmitter for up-converting and amplifying the transmitted signal, and an RF receiver for down-converting the received signal. However, according to another embodiment, transceiver 1520 may be implemented with more or fewer components than those illustrated.

[0143] Transceiver 1520 can be connected to processor 1510 and send and / or receive signals, which may include control information and data. Furthermore, transceiver 1520 can receive signals via a wireless channel and output signals to processor 1510. Transceiver 1520 can also transmit signals output by processor 1510 via a wireless channel.

[0144] Memory 1530 may store control information or data contained in signals acquired by network entity 1500. Memory 1530 may be connected to processor 1510 and store at least one instruction, protocol, or parameter for the proposed function, process, and / or method. Memory 1530 may include read-only memory (ROM) and / or random access memory (RAM) and / or hard disk and / or CD-ROM and / or DVD and / or other storage devices.

[0145] Certain examples of this disclosure provide apparatus / device / network entities configured to perform one or more defined network functions, and corresponding methods. Such apparatus / device / network entities may include one or more elements (e.g., receivers, transmitters, transceivers, processors, controllers, modules, units, etc.), each element configured to perform one or more corresponding process, operational, and / or method steps to implement the techniques described herein. For example, operation / function of X may be performed by a module (or X module) configured to perform X. Certain examples of this disclosure provide systems (e.g., networks) including one or more such apparatus / device / network entities, and corresponding methods. For example, in the following example, a network may include one or more IAB nodes.

[0146] It should be understood that the examples of this disclosure can be implemented by hardware, software, or a combination of hardware and software. Certain examples of this disclosure may provide a computer program, including instructions or code, which, when executed by a computer or processor, implements the methods, systems, and / or apparatus described in any aspect, claim, example, and / or embodiment thereof. Certain embodiments of this disclosure provide a machine-readable storage medium for storing such programs.

[0147] Identical or similar components may be identified by the same or similar reference numerals, although they may be shown in different figures.

[0148] For the sake of clarity and brevity, and to avoid obscuring the subject matter of this disclosure, detailed descriptions of techniques, structures, constructions, functions, or processes known in the art may be omitted.

[0149] The terms and words used herein are not limited to their bibliographical or standard meanings, but are used only to enable the examples in this disclosure to be understood clearly and consistently.

[0150] Throughout the description and claims, the words “comprising” and “including” and their variations (e.g., “comprising” and “containing”) mean “including but not limited to” and are not intended to (and will not) exclude other features, elements, components, integers, steps, processes, functions, characteristics, etc.

[0151] Throughout the description and claims, the singular form encompasses the plural form unless the context requires otherwise. For example, reference to “object” includes reference to one or more such objects.

[0152] Throughout the description and claims, the general form of “X for Y” (where Y is some action, process, function, activity or step, and X is means for performing that action, process, function, activity or step) covers means X specifically adapted, configured or arranged to perform Y, but is not necessarily limited to performing Y.

[0153] Features, elements, components, integers, steps, processes, functions, characteristics, etc., described in conjunction with a particular aspect, embodiment, example, or claim should be understood to be applicable to any other aspect, embodiment, example, or claim disclosed herein, unless incompatible with it.

[0154] Although this disclosure has been shown and described with reference to certain examples, those skilled in the art will understand that various changes in form and detail may be made without departing from the scope of this disclosure as defined by the appended claims.

[0155] Furthermore, computer-readable storage media can be provided as non-transitory storage media. "Non-transitory storage media" is a tangible device, meaning only that it does not contain signals (e.g., electromagnetic waves). This term does not distinguish between cases where data is semi-permanently stored in a storage medium and cases where data is temporarily stored in a storage medium. For example, a non-transitory recording medium may include a buffer for temporarily storing data.

[0156] The specific examples used to explain embodiments according to this disclosure are merely combinations of various standards, methods, detailed methods, and operations, and the various embodiments described herein can be implemented by combining at least two or more of the various techniques described herein. Furthermore, the method can be performed by combining one or more of the above-described techniques. For example, parts of one embodiment can be combined with parts of another embodiment.

[0157] Abbreviations / Definitions

[0158] In this disclosure, the following abbreviations and definitions in Table 4 may be used: [Table 4]

Claims

1. A method for a user equipment (UE) in a wireless communication system, comprising: The System Information Block (SIB) is obtained from the base station (BS). The SIB includes information related to the Different Radio Access Technology (RAT) cell. The related information of the different RAT cells includes at least one of the following: information about frequencies having one or more Mobile Integrated Access Backhaul (IAB) cells, or information about a list of one or more Mobile IAB cells; and In the event of a different RAT mobile IAB cell being detected, the different RAT frequency used for the different RAT mobile IAB cell is considered to have the highest priority for cell reselection.

2. The method of claim 1, wherein the information regarding the frequency of one or more mobile IAB cells indicates that the one or more mobile IAB cells are deployed on the different RAT frequency.

3. The method according to claim 1, wherein the SIB is a type 24 SIB.

4. The method according to claim 1, further comprising: Acquire SIB 1, including information indicating that the different RAT cell is a mobile IAB cell; as well as Based on the information included in SIB 1, different RAT mobile IAB cells are identified.

5. The method according to claim 1, The BS refers to an Evolved Universal Terrestrial Radio Access Network (E-UTRAN) cell. The aforementioned RATIAB cell is a New Radio Interface (NR) mobile IAB cell, and The different RAT frequency is the NR frequency.

6. The method according to claim 1, further comprising: The BS receives a Radio Resource Control (RRC) release message, which includes auxiliary information for different RAT mobile IAB cells. as well as Based on the auxiliary information of the different RAT mobile IAB cell included in the RRC release message, redirection is performed to the different RAT mobile IAB cell.

7. A method for using a base station (BS) in a wireless communication system, comprising: The System Information Block (SIB) includes information related to Different Radio Access Technologies (RAT) cells. The related information of the different RAT cells includes at least one of the following: information about frequencies having one or more Mobile Integrated Access Backhaul (IAB) cells, or information about a list of one or more Mobile IAB cells; and In the case of detecting a different RAT mobile IAB cell, the different RAT frequency used for the different RAT mobile IAB cell is considered to have the highest priority for cell reselection.

8. A user equipment (UE) in a wireless communication system, comprising: Memory, which stores one or more instructions; as well as At least one processor is configured to execute the one or more instructions to achieve: The System Information Block (SIB) is obtained from the base station (BS). The SIB includes information related to the Different Radio Access Technology (RAT) cell. The related information of the different RAT cells includes at least one of the following: information about the frequency of one or more Mobile Integrated Access Backhaul (IAB) cells, or information about a list of one or more Mobile IAB cells; as well as In the event of a different RAT mobile IAB cell being detected, the different RAT frequencies used for the different RAT mobile IAB cell are considered to have the highest priority for cell reselection.

9. The UE of claim 8, wherein the information regarding the frequency of one or more mobile IAB cells indicates that the one or more mobile IAB cells are deployed on the different RAT frequency.

10. The UE according to claim 8, wherein the SIB is a type 24 SIB.

11. The UE of claim 8, wherein the at least one processor is further configured to execute the one or more instructions to achieve: SIB 1, which includes information indicating that the RAT cell is a mobile IAB cell, is acquired; and Based on the information included in SIB 1, different RAT mobile IAB cells are identified.

12. The UE according to claim 8, The BS refers to an Evolved Universal Terrestrial Radio Access Network (E-UTRAN) cell. The aforementioned RATIAB cell is a New Radio Interface (NR) mobile IAB cell, and The different RAT frequency is the NR frequency.

13. The UE of claim 8, wherein the at least one processor is further configured to execute the one or more instructions to achieve: The BS receives a Radio Resource Control (RRC) release message, which includes inter-RAT Mobile IAB cell assistance information; and Based on the auxiliary information of the different RAT mobile IAB cell included in the RRC release message, redirection is performed to the different RAT mobile IAB cell.

14. A base station (BS) in a wireless communication system, comprising: Memory, which stores one or more instructions; as well as At least one processor is configured to execute the one or more instructions to achieve: The broadcast packet System Information Block (SIB) includes information related to Different Radio Access Technologies (RAT) cells. The related information of the different RAT cells includes at least one of the following: information about frequencies having one or more Mobile Integrated Access Backhaul (IAB) cells, or information about a list of one or more Mobile IAB cells; and In the case of detecting a different RAT mobile IAB cell, the different RAT frequency used for the different RAT mobile IAB cell is considered to have the highest priority for cell reselection.

15. The BS of claim 14, wherein the information regarding the frequency of one or more mobile IAB cells indicates that the one or more mobile IAB cells are deployed on the different RAT frequency.

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