Network controlled repeater, radio access network node, and methods therefor

Abstract

A network controlled repeater (1) includes a repeater unit (11) and a controller (12). The repeater unit (11) is provided with a radio frequency (RF) component and configured to amplify and forward an RF signal. The controller (12) is coupled to the repeater unit (11) and configured to provide an NCR mobile termination (NCR-MT). The controller (12) is configured to, in order to determine whether a cell satisfies a cell selection standard or not, use second minimum required reception power or minimum required quality level specific to the NCR-MT in the cell, which is different from first minimum required reception power or minimum required quality level in the cell for normal user equipment (UE) that is not NCR-MT. This can contribute, for example, to the regulation of access to the cell by the controller of the NCR.

Description

Network-controlled repeater, radio access network node, and methods thereof

[0001] The present disclosure relates to wireless communication systems and to a Network Controlled Repeater (NCR).

[0002] For the 3rd Generation Partnership Project (3GPP®) Release 18, 3GPP is discussing the Network Controlled Repeater (NCR) (see, for example, Non-Patent Documents 1-6). The NCR is a Radio Frequency (RF) repeater that has been enhanced to have the capability to receive and process side control information from the network. The RF repeater is a type of network node that simply amplifies and forwards the received signal. The NCR is sometimes called a smart repeater.

[0003] The NCR has an NCR-Forwarding (NCR-Fwd) function and an NCR-Mobile termination (NCR-MT) function. The NCR-Fwd may also be called an NCR Repeater Unit (NCR-RU) or an NCR Radio Unit (NCR-RU). The NCR-MT may also be called an NCR-Mobile terminal, controller, or NCR controller. The NCR-Fwd is defined as a functional entity that amplifies and forwards uplink (UL) and downlink (DL) RF signals between the gNB and the User Equipment (UE) via the backhaul link and access link. The NCR-MT is defined as a functional entity that communicates with the gNB via the control link to enable the exchange of control information (e.g., side control information for controlling at least the NCR-Fwd). The operation of the NCR-Fwd is controlled according to the side control information received from the gNB.

[0004] ZTE Corporation, "New SI: Study on NR Network-controlled Repeaters", RP-213700, 3GPP TSG RAN Meeting #94e, December 6-17, 2021 3GPP TR 38.867 V1.0.0 (2022-09) "3rd Generation Partnership Project; Technical Specification Group Radio Access network; Study on NR network-controlled repeaters; (Release 18)", September 2022 Huawei, HiSilicon, "Discussions on side control information to enable NR network-controlled repeaters", R1-2203133, 3GPP TSG RAN WG1 Meeting #109-e, May 9-20, 2022 ZTE, "Discussion on side control information to enable NR network-controlled repeaters", R1-2203237, 3GPP TSG RAN WG1 Meeting #109-e, May 9-20, 2022 Vivo, "Discussion on side control information to enable NR network-controlled repeaters", R1-2203578, 3GPP TSG RAN WG1 Meeting #109-e, May 9-20, 2022 Samsung, "Side control information to enable NR network-controlled repeaters", R1-2203921, 3GPP TSG RAN WG1 Meeting #109-e, May 9-20, 2022

[0005] The inventors have studied NCR and found various problems. One of these problems relates to the restriction of cell access by NCR-MT. Non-Patent Documents 1-6 do not disclose a method for restricting cell access by NCR-MT.

[0006] One of the objectives to be achieved by the embodiments disclosed in this specification is to provide an apparatus, a method, and a program that contribute to regulating access to a cell by a controller of a network-controlled repeater (e.g., NCR-MT). It should be noted that this objective is only one of the objectives to be achieved by the embodiments disclosed in this specification. Other objectives or problems and novel features will become apparent from the description of this specification or the accompanying drawings.

[0007] In a first aspect, an NCR comprises a repeater unit and a controller. The repeater unit comprises RF components and is configured to amplify and forward RF signals. The controller is coupled to the repeater unit and configured to provide an NCR-MT. The controller is further configured to use a second minimum required received power or minimum required quality level specific to the NCR-MT in a cell to determine whether the cell satisfies a cell selection criterion. The second minimum required received power or minimum required quality level is different from a first minimum required received power or minimum required quality level in the cell for normal user equipment (UE) that is not an NCR-MT.

[0008] In a second aspect, the method performed by the NCR includes using a second NCR-MT-specific minimum required received power or minimum required quality level at a cell to determine whether the cell satisfies the cell selection criteria, the second minimum required received power or minimum required quality level being different from a first minimum required received power or minimum required quality level at the cell for non-NCR-MT normal user equipment (UE).

[0009] In a third aspect, a Radio Access Network (RAN) node is configured to broadcast cell selection information in a cell. The cell selection information includes a first parameter and further includes a second parameter or a third parameter. The first parameter represents a first minimum required received power or a minimum required quality level in the cell used for cell selection by a normal UE other than an NCR-MT. The second parameter represents a second minimum required received power or a minimum required quality level in the cell used for cell selection by the NCR-MT. The third parameter is used by the NCR-MT to determine the second minimum required received power or minimum required quality level from the first parameter.

[0010] In a fourth aspect, a method performed by a RAN node includes broadcasting cell selection information in a cell, the cell selection information including a first parameter and further including a second parameter or a third parameter, the first parameter representing a first minimum required received power or minimum required quality level in the cell used for cell selection by a normal UE other than an NCR-MT, the second parameter representing a second minimum required received power or minimum required quality level in the cell used for cell selection by the NCR-MT, and the third parameter being used by the NCR-MT to determine the second minimum required received power or minimum required quality level from the first parameter.

[0011] In a fifth aspect, an NCR comprises a repeater unit and a controller. The repeater unit comprises an RF component and is configured to amplify and forward RF signals between a RAN node and UEs. The controller is coupled to the repeater unit and configured to communicate with the RAN node via a control link to exchange control information. The controller is configured to receive a Radio Resource Control (RRC) release message from the RAN node requesting release of an RRC connection in a cell and indicating an access restriction period. The controller is further configured not to initiate a random access procedure to the cell when a received power or reception quality level in the cell is lower than a threshold, at least until the access restriction period has elapsed.

[0012] In a sixth aspect, a method performed by an NCR includes the steps of: (a) receiving an RRC release message from a RAN node requesting release of an RRC connection in a cell and indicating an access restriction period; and (b) if a received power or received quality level in the cell is lower than a threshold, not initiating a random access procedure to the cell until at least the access restriction period has elapsed.

[0013] In a seventh aspect, a RAN node is configured to determine release of an RRC connection in a cell for an NCR in response to a decrease or lack of a received power or received quality level of the NCR in the cell, and to send an RRC release message to the NCR indicating an access barring period, the RRC release message causing the NCR not to initiate a random access procedure to the cell if the received power or received quality level in the cell is below a threshold value, at least until the access barring period has elapsed.

[0014] In an eighth aspect, a method performed by a RAN node includes determining to release an RRC connection in a cell for an NCR in response to a decrease or lack of received power or received quality level of the NCR in the cell, and sending an RRC release message to the NCR indicating an access barring period, the RRC release message causing the NCR to not initiate a random access procedure to the cell if the received power or received quality level in the cell is below a threshold value until at least the access barring period has elapsed.

[0015] In a ninth aspect, an NCR comprises a repeater unit and a controller. The repeater unit comprises RF components and is configured to amplify and forward RF signals between a RAN node and UEs. The controller is coupled to the repeater unit and configured to communicate with the RAN node via a control link to exchange control information. The controller is configured to send an RRC setup or resumption message requesting establishment or resumption of an RRC connection in a cell. The RRC setup or resumption message indicates measurements of the cell recorded when the NCR was in RRC_IDLE or RRC_INACTIVE.

[0016] In a tenth aspect, a method performed by an NCR includes transmitting an RRC setup or resumption message requesting establishment or resumption of an RRC connection in a cell, the RRC setup or resumption message indicating measurements for the cell recorded when the NCR was in RRC_IDLE or RRC_INACTIVE.

[0017] In an eleventh aspect, the RAN node is configured to receive an RRC setup or resumption message from an NCR requesting the establishment or resumption of an RRC connection in a cell, the RRC setup or resumption message indicating measurements for the cell recorded when the NCR was in RRC_IDLE or RRC_INACTIVE.

[0018] In a twelfth aspect, a method performed by a RAN node includes receiving an RRC setup or resumption message from an NCR requesting establishment or resumption of an RRC connection in a cell, the RRC setup or resumption message indicating measurements for the cell recorded when the NCR was in RRC_IDLE or RRC_INACTIVE.

[0019] In a thirteenth aspect, an NCR comprises a repeater unit and a controller. The repeater unit comprises RF components and is configured to amplify and forward RF signals between a RAN node and UEs. The controller is coupled to the repeater unit and configured to communicate with the RAN node via a control link to exchange control information. The controller is configured to send an RRC setup or resumption complete message indicating completion of establishment or resumption of an RRC connection in a cell. The RRC setup or resumption complete message indicates measurement results for the cell that were recorded when the NCR was in RRC_IDLE or RRC_INACTIVE.

[0020] In a fourteenth aspect, a method performed by an NCR includes transmitting an RRC Setup or Resumption Complete message indicating completion of establishment or resumption of an RRC connection in a cell, the RRC Setup or Resumption Complete message indicating measurements for the cell recorded when the NCR was in RRC_IDLE or RRC_INACTIVE.

[0021] In a fifteenth aspect, the RAN node is configured to receive an RRC Setup or Resumption Complete message from an NCR indicating completion of establishment or resumption of an RRC connection in a cell, the RRC Setup or Resumption Complete message indicating measurements for the cell recorded when the NCR was in RRC_IDLE or RRC_INACTIVE.

[0022] In a sixteenth aspect, a method performed by a RAN node includes receiving an RRC setup or resumption complete message from an NCR indicating completion of establishment or resumption of an RRC connection in a cell, the RRC setup or resumption complete message indicating measurements for the cell recorded when the NCR was in RRC_IDLE or RRC_INACTIVE.

[0023] A seventeenth aspect is directed to a program, the program including a set of instructions (software code) that, when loaded into a computer, causes the computer to perform the method according to the second, fourth, sixth, eighth, tenth, twelfth, fourteenth, or sixteenth aspect.

[0024] According to the above-described aspects, it is possible to provide an apparatus, a method, and a program that contribute to restricting access to a cell by a controller (eg, NCR-MT) of a network-controlled repeater.

[0025] 1 is a diagram illustrating an example of the configuration of a wireless communication system according to an embodiment. FIG. 2 is a diagram illustrating an example of the configuration of an NCR according to an embodiment. FIG. 3 is a diagram for explaining the operation of an NCR according to an embodiment. FIG. 4 is a flowchart illustrating an example of the operation of an NCR according to an embodiment. FIG. 5 is a sequence diagram illustrating an example of the operation of a gNB and an NCR according to an embodiment. FIG. 6 is a sequence diagram illustrating an example of the operation of a gNB and an NCR according to an embodiment. FIG. 7 is a block diagram illustrating an example of the configuration of a gNB according to an embodiment. FIG. 8 is a diagram illustrating an example of the configuration of an NCR-MT or a controller according to an embodiment.

[0026] Hereinafter, specific embodiments will be described in detail with reference to the drawings. In each drawing, the same or corresponding elements are designated by the same reference numerals, and for clarity of explanation, duplicate explanations will be omitted as necessary.

[0027] The following embodiments are described with respect to the 3GPP 5th generation mobile communication system (5G system) and its evolution, but may also be applied to other wireless communication systems that use network-controlled repeaters.

[0028] As used herein, depending on the context, "if" may be interpreted to mean "when," "at or around the time," "after," "upon," "in response to determining," "in accordance with a determination," or "in response to detecting." These expressions may be interpreted to have the same meaning, depending on the context.

[0029] First, the configurations and operations of multiple network elements common to multiple embodiments will be described. Figure 1 shows an example configuration of a wireless communication system according to multiple embodiments. Each of the elements shown in Figure 1 is a network function, and provides an interface defined by, for example, 3GPP. Each element (network function) shown in Figure 1 can be implemented, for example, as a network element on dedicated hardware, as a software instance running on dedicated hardware, or as a virtualized function instantiated on an application platform.

[0030] The network system shown in FIG. 1 includes an NCR 1, a gNB 2, and a UE 3. The gNB 2 may be referred to as a radio access network (RAN) node, base station, radio station, or access point. The UE 3 may be referred to by other terms, such as a wireless terminal, mobile terminal, mobile station, or wireless transmit receive units (WTRUs). The gNB 2 may be a combination of a gNB-Central Unit (gNB-CU) and one or more gNB-Distributed Units (gNB-DUs) in a cloud RAN (C-RAN) deployment. The C-RAN is also referred to as a CU / DU split. Furthermore, the gNB-CU may include a Control Plane (CP) Unit (i.e., gNB-CU-CP) and one or more User Plane (UP) Units (i.e., gNB-CU-UPs).

[0031] The NCR 1 includes an NCR-Forwarding (NCR-Fwd) 11 and an NCR-Mobile termination (NCR-MT) 12. The NCR-Fwd 11 may also be referred to as an NCR Repeater Unit (NCR-RU) or an NCR Radio Unit (NCR-RU). The NCR-MT 12 may also be referred to as an NCR-Mobile terminal, controller, or NCR controller. The NCR-Fwd 11 is defined as a functional entity that amplifies and forwards UL and DL RF signals between the gNB 2 and the UE 3 via a backhaul link and an access link. The NCR-MT 12 is defined as a functional entity that communicates with the gNB 2 via a control link to enable the exchange of control information (e.g., side control information for controlling at least the NCR-Fwd 11). The operation of the NCR-Fwd 11 is controlled according to the side control information received from the gNB 2. NCR-MT 12 may provide side control information received from gNB 2 to NCR-Fwd 11. NCR-MT 12 may control the operation of NCR-Fwd 11 according to the side control information received from gNB 2.

[0032] The control link between the NCR-MT 12 and the gNB 2 may reuse legacy beam management mechanisms. It is reasonable to assume that heavy data transmission other than beam management reports is not performed on the control link. Therefore, the NCR-MT 12 does not necessarily need to be a full-featured UE. For example, it may support the functionality defined for Reduced Capability (RedCap) UEs in 3GPP Release 17. RedCap UEs have reduced functionality compared to non-RedCap UEs, aiming for low complexity. RedCap UEs are required to support a maximum UE channel bandwidth of 20 MHz in FR1 (i.e., sub-6 GHz bands) and 100 MHz in FR2 (i.e., millimeter wave (mmWave) bands). Meanwhile, Carrier Aggregation (CA), Multi-Radio Dual Connectivity (MR-DC), Dual Active Protocol Stack (DAPS), and Integrated Access and Backhaul (IAB)-related features are not supported by RedCap UEs. For RedCap UEs, the minimum number of UE Reception (Rx) branches and the maximum number of Downlink (DL) Multiple Input Multiple Output (MIMO) layers are reduced or relaxed compared to those for non-RedCap UEs.

[0033] FIG. 2 shows an example configuration of the NCR 1. In the example of FIG. 2, the NCR-RU or NCR-Fwd 11 includes a downlink RF chain (or branch) including an amplifier 13 and an uplink RF chain (or branch) including an amplifier 14. The downlink RF chain may include other RF components. For example, the downlink RF chain may include one or more bandpass filters, multiple mixers (upconverters and downconverters), and one or more amplifiers. Similarly, the uplink RF chain may include other RF components, such as one or more bandpass filters, multiple mixers (upconverters and downconverters), and one or more amplifiers. Note that FIG. 2 illustrates the NCR for Time Division Duplex (TDD) mode. Therefore, connections to the gNB side antenna 15 and the UE side antenna 16 are switched between the downlink RF chain and the uplink RF chain according to a UL-DL TDD configuration. The NCR-Fwd 11 and the NCR-MT 12 share the gNB side antenna 15 and parts of the downlink and uplink RF chains.

[0034] First Embodiment This embodiment provides details of cell selection performed by the NCR (or NCR-MT). In this embodiment, the NCR-MT 12 uses an NCR-MT-specific second minimum required received power or minimum required quality level for a cell, which is different from the first minimum required received power or minimum required quality level for a normal UE that is not an NCR-MT, to determine whether the cell of the gNB 2 satisfies the cell selection criteria. Note that the NCR-MT 12 may perform cell selection using both the NCR-MT-specific second minimum required received power level and the NCR-MT-specific second minimum required received quality level. The minimum required received power level for a cell determines a minimum required level of Reference Signal Received Power (RSRP) for the cell. The minimum required received quality level for a cell determines a minimum required level of Reference Signal Received Quality (RSRQ) for the cell. The RSRP may be Synchronization Signal (SS) RSRP. The RSRQ may be SS-RSRQ.

[0035] Network operators may have NCR-specific requirements for backhaul links to ensure performance of NCR deployments. For example, NCR may be deployed only in areas where a measurement level greater than a second minimum required received power or minimum required quality level specific to NCR-MTs is obtained. More specifically, as shown in FIG. 3, the second minimum required received power or minimum required quality level specific to NCR-MTs may be defined to be greater than the first minimum required received power or minimum required quality level for non-NCR-MT UEs (or normal UEs).

[0036] 4 shows an example of the operation of NCR-MT 12. In step 401, NCR-MT 12 receives cell selection information broadcast in a cell. In step 402, NCR-MT 12 determines whether a cell satisfies the cell selection criteria using an NCR-MT-specific second minimum required received power (or minimum required quality) level in the cell, which is different from the first minimum required received power (or required quality level) in the cell for the normal UE. As described above, NCR-MT 12 may perform cell selection using both the NCR-MT-specific second minimum required received power level and the NCR-MT-specific second minimum required received quality level.

[0037] The gNB 2 broadcasts cell selection information in the cell. In a first implementation, the cell selection information may include a first parameter (e.g., q-RxLevMin, q-QualMin) representing a first minimum required received power or a minimum required quality level, as well as a second parameter (e.g., q-RxLevMin_NCR, q-QualMin_NCR) representing a second minimum required received power or a minimum required quality level. In this case, the NCR-MT 12 uses the second minimum required received power or minimum required quality level indicated by the second parameter to determine whether the cell satisfies the cell selection criteria.

[0038] In a second implementation, the cell selection information includes a first parameter representing a first minimum required received power or a minimum required quality level, as well as a third parameter (e.g., an offset) for deriving a second minimum required received power or a minimum required quality level from the first parameter. In this case, the NCR-MT 12 calculates the second minimum required received power or a minimum required quality level using the first parameter and the third parameter. The NCR-MT 12 then uses the obtained second minimum required received power or a minimum required quality level to determine whether the cell satisfies the cell selection criteria.

[0039] In a third implementation, a third parameter is defined in the specification. In other words, the third parameter (e.g., an offset) is preset in the NCR-MT 12. Therefore, in the third implementation, the cell selection information includes a first parameter representing a first minimum required received power or a minimum required quality level, but does not include either the second parameter or the third parameter. In this case, the NCR-MT 12 derives a second minimum required received power or a minimum required quality level from the first parameter using the predefined third parameter (e.g., an offset). The NCR-MT 12 then uses the obtained second minimum required received power or minimum required quality level to determine whether the cell satisfies the cell selection criteria.

[0040] 5 shows an example of the operation of NCR 1 and gNB 2 in the first or second implementation described above. In step 501, gNB 2 broadcasts cell selection information in its cell. The cell selection information includes a first parameter for non-NCR-MT UEs (normal UEs) and a second or third parameter for NCR-MTs. In step 503, NCR 1 (NCR-MT 12) uses the second or third parameter to determine whether the cell satisfies the cell selection criteria.

[0041] The cell selection criterion for NCR-MTs may be the same as the existing cell selection criterion S in the 5G system. For example, the cell selection criterion for NCR-MTs is satisfied when Srxlev > 0 AND Squal > 0. Srxlev and Squal are as follows: Srxlev = Q rxlevmeas - (Q rxlevmin_NCR + Q rxlevminoffset ) - P compensation - Qoffset temp , and Squal = Q qualmeas - (Q qualmin_NCR + Q qualminoffset ) - Qoffset temp .

[0042] Q rxlevmin_NCR is the second minimum required received power level for NCR-MT. qualmin_NCRis the second minimum required reception quality level for NCR-MT. Q rxlevminoffset and Q qualminoffset is the offset used to search for higher priority PLMNs when the UE is camped on a Visited Public Land Mobile Network (VPLMN). Therefore, in the cell selection criteria for NCR-MT, Q rxlevminoffset and Q qualminoffset may be zero or omitted. For NCR-MT, P compensation Qoffset can be zero. temp is the offset applied when the RRC connection establishment fails, and is indicated by the connEstFailOffset field in the ConnEstFailureControl information element in System Information Block Type 1 (SIB1). If there is no such field in SIB1, Qoffset temp A value of infinity is applied to Qoffset temp The period for which this applies is indicated by the connEstFailOffsetValidity field in the ConnEstFailureControl information element.

[0043] Q rxlevmin_NCR and Q qualmin_NCR Only one of these may be used. For example, Q rxlevmin_NCR is used, and Q qualmin_NCR may not be used. In this case, Q qualmin_NCR Instead of Q for non-NCR-MT UE (normal UE) qualmin may be used.

[0044] According to the operation described in this embodiment, the NCR-MT 12 can determine whether a cell satisfies the cell selection criteria using the minimum required received power or minimum required quality level specific to the NCR-MT, which can contribute to restricting access to the cell of the NCR 1 (NCR-MT 12) according to the cell selection criteria specific to the NCR-MT, which are different from those for the normal UE.

[0045] Second Embodiment This embodiment provides an improved RRC release procedure. Figure 6 shows an example of the operations of NCR1 (NCR-MT 12) and gNB2. In step 601, gNB2 sends an RRC Release message to NCR1 (NCR-MT 12) indicating an access restriction period. The RRC Release message requests NCR1 (NCR-MT 12) to release the Radio RRC connection in the cell. In addition, if the received power (e.g., RSRP) or received quality (e.g., RSRQ) level in the cell is lower than a threshold, the RRC Release message causes NCR1 (NCR-MT 12) to refrain from initiating a random access procedure to the cell until at least the access restriction period has elapsed. The RRC Release message may further indicate the threshold. NCR1 (NCR-MT 12) may perform threshold determination for both the received power (e.g., RSRP) level and the received quality (e.g., RSRQ) level. In this case, the RRC release message may indicate two thresholds for the received power (eg, RSRP) level and the received quality (eg, RSRQ) level, respectively.

[0046] In step 602, the NCR 1 (NCR-MT 12) releases the RRC connection in the cell, and if the received power or received quality level in the cell is lower than a threshold, the NCR 1 (NCR-MT 12) operates not to initiate a random access procedure to the cell until at least the access restriction period has elapsed.

[0047] The access restriction period may be one hour or more. For example, the access restriction period may indicate one of 1 hour, 2 hours, 4 hours, 8 hours, 16 hours, 1 day, 3 days, and 7 days.

[0048] In response to a decrease or insufficiency in the received power or received quality level of NCR 1 (NCR-MT 12), gNB 2 may decide to release the RRC connection in the cell for NCR 1 (NCR-MT 12). In this case, the RRC release message of step 601 may indicate that the cause of the release of the RRC connection is a decrease or insufficiency in the received power or received quality level in the cell.

[0049] The gNB 2 may provide a measurement configuration to the NCR-MT 12 that is RRC_CONNECTED in the cell. The measurement configuration may include at least a measurement object for serving cell measurements and a reporting configuration associated with the measurement object. The reporting configuration may specify Event A2 (i.e., Serving becomes worse than threshold). The serving cell measurement value may be RSRP, RSRQ, or Signal to Interference Noise Ratio (SINR). RSRP, RSRQ, and SINR may be SS-RSRP, SS-RSRQ, or SS-SINR. In this case, the gNB 2 may receive a measurement report triggered by Event A2 from the NCR-MT 12 and decide to release the RRC connection of the NCR-MT 12 based on the serving cell measurement value indicated by the measurement report.

[0050] Alternatively, the gNB 2 may send a Logged Measurement Configuration to the NCR-MT 12 that is RRC_CONNECTED in the cell. The Logged Measurement Configuration configures the NCR-MT 12 to perform logging of measurement results when in the RRC_IDLE or RRC_INACTIVE state. The Logged Measurement Configuration may specify an Event L1 trigger, which is similar to Event A2 for measurements in RRC_CONNECTED. If the reportType field in the Logged Measurement Configuration is set to eventTriggered and the eventType field is set to eventL1, the NCR-MT 12 performs logging when the cell on which the NCR-MT 12 is camped (i.e., the serving cell) in the normal camped state satisfies event L1 (i.e., the camping cell becomes worse than the threshold). When logging, the NCR-MT 12 records measurements of the cell on which the NCR-MT 12 is camped. In this case, after NCR-MT 12 transitions to RRC_CONNECTED, gNB 2 may request NCR-MT 12 to report information about logged measurements using the UE Information procedure, and gNB 2 may decide to release the RRC connection of NCR-MT 12 based on the serving cell measurement results recorded when NCR-MT 12 was in RRC_IDLE or RRC_INACTIVE.

[0051] Alternatively, the gNB 2 may provide the Idle / inactive Measurement configuration to the NCR-MT 12 in an RRC Release message (sent before step 601, different from step 601) for moving the NCR-MT 12 from RRC_CONNECTED to RRC_IDLE or RRC_INACTIVE. The Idle / inactive Measurement configuration configures the NCR-MT 12 to measure the last serving cell (or the current camped cell in the normal camped state) in the RRC_IDLE and RRC_INACTIVE states. When in RRC_IDLE or RRC_INACTIVE, the NCR-MT 12 records measurements of the cell on which the NCR-MT 12 is camped (i.e., the serving cell). In this case, after the NCR-MT 12 transitions to RRC_CONNECTED, the gNB 2 may request the NCR-MT 12 to report information about the Idle / inactive Measurements using the UE Information procedure. Then, gNB 2 may decide to release the RRC connection of NCR-MT 12 based on the serving cell measurement results recorded when NCR-MT 12 is in RRC_IDLE or RRC_INACTIVE.

[0052] According to the operation described in this embodiment, when gNB 2 releases the RRC connection of NCR 1 whose control link quality is low (and therefore whose backhaul link quality is also expected to be low), it can control NCR 1 not to attempt cell access until the quality recovers or the access restriction period has elapsed. This can contribute to restricting access to the cell of NCR 1 (NCR-MT 12) whose control link quality is low.

[0053] Third Embodiment This embodiment provides an improvement to the RRC setup procedure. Figure 7 shows an example of the operation of NCR 1 (NCR-MT 12) and gNB 2. In step 701, NCR 1 (NCR-MT 12) transmits an RRC Setup Request message or an RRC Resume Request message. The RRC Setup Request message is transmitted to request establishment of an RRC connection in a cell when NCR 1 (NCR-MT 12) is in RRC_IDLE. The RRC Resume Request message is transmitted to request resumption of an RRC connection in a cell when NCR 1 (NCR-MT 12) is in RRC_INACTIVE.

[0054] The RRC setup or resumption request message in step 701 indicates the measurement results of the cell (i.e., the cell on which NCR-MT 12 is camped, the serving cell) recorded when NCR 1 (NCR-MT 12) was in RRC_IDLE or RRC_INACTIVE. The measurement results of the cell indicate measurements of the received power (e.g., RSRP) or quality (e.g., RSRQ, SINR) of the serving cell. The measurement results of the cell may be recorded based on the logged measurement configuration or based on the idle / inactive measurement configuration. The logged measurements and idle / inactive measurements may be performed in the same way as those described in the second embodiment.

[0055] The RRC setup or resumption request message of step 701 can provide the gNB 2 with measurement results of the serving cell (i.e., the cell on which the NCR-MT 12 is camped) earlier than using the existing UE information procedure. In one example, the gNB 2 can obtain the measurement results before establishing or resuming the RRC connection and can decide whether to reject the RRC connection establishment or resumption based on the measurement results.

[0056] By way of example and not limitation, gNB 2 may perform steps 702 and 703. In step 702, gNB 2 decides to reject the request message of step 701 based on the provided measurement results. In step 703, gNB 2 sends an RRC rejection message to NCR 1 (NCR-MT 12). The RRC rejection message may indicate that the rejection of the RRC connection establishment or resumption is due to insufficient received power or received quality level in the cell.

[0057] Additionally or alternatively, the RRC rejection message may indicate an access restriction period. In this case, if the received power (e.g., RSRP) or received quality (e.g., RSRQ) level at the cell is lower than a threshold, the RRC rejection message triggers the NCR 1 (NCR-MT 12) to refrain from initiating a random access procedure to the cell until at least the access restriction period has elapsed. The RRC rejection message may further indicate the threshold. The NCR 1 (NCR-MT 12) may perform threshold determination for both the received power (e.g., RSRP) level and the received quality (e.g., RSRQ) level. In this case, the RRC rejection message may indicate two thresholds, one for the received power (e.g., RSRP) level and the other for the received quality (e.g., RSRQ) level. If the received power or received quality level at the cell is lower than a threshold, the NCR 1 (NCR-MT 12) refrains from initiating a random access procedure to the cell until at least the access restriction period has elapsed. The access restriction period may be one hour or more. For example, the access restriction period may indicate one of 1 hour, 2 hours, 4 hours, 8 hours, 16 hours, 1 day, 3 days, or 7 days.

[0058] According to the operations of steps 702 and 703, gNB 2 can reject the establishment or resumption of an RRC connection for NCR 1 whose control link quality is low (and therefore whose backhaul link quality is also expected to be low), and can control NCR 1 not to attempt cell access until the quality recovers or the access restriction period has elapsed. This can contribute to restricting access to a cell for NCR 1 (NCR-MT 12) whose control link quality is low.

[0059] Fourth Embodiment This embodiment provides an improvement to the RRC setup procedure. Figure 8 shows an example of the operation of the NCR 1 (NCR-MT 12) and the gNB 2. In step 801, the NCR 1 (NCR-MT 12) transmits an RRC Setup Complete message or an RRC Resume Complete message. The RRC Setup Complete message indicates that the NCR 1 (NCR-MT 12) has completed the establishment of the RRC connection. In other words, the RRC Setup Complete message is transmitted when the NCR 1 (NCR-MT 12) has transitioned from RRC_IDLE or RRC_INACTIVE to RRC_CONNECTED. The RRC Resume Complete message indicates that the NCR 1 (NCR-MT 12) has completed the resumption of the RRC connection. In other words, the RRC Resume Complete message is transmitted when the NCR 1 (NCR-MT 12) has transitioned from RRC_INACTIVE to RRC_CONNECTED.

[0060] The RRC Setup or Resumption Complete message in step 801 indicates the measurement results of the cell (i.e., the cell on which NCR-MT 12 is camped or the serving cell of NCR-MT 12) recorded when NCR 1 (NCR-MT 12) was in RRC_IDLE or RRC_INACTIVE. The measurement results of the cell indicate measurements of the received power (e.g., RSRP) or quality (e.g., RSRQ, SINR) of the serving cell of NCR-MT 12. The measurement results of the cell may be recorded based on the Logged Measurement Configuration or the Idle / inactive Measurement configuration. The logged measurements and idle / inactive measurements may be performed in the same manner as those described in the second embodiment.

[0061] The RRC setup or resumption complete message of step 801 can provide the serving cell measurement results to gNB 2 earlier than using the existing UE information procedure. In one example, gNB 2 can obtain the measurement results immediately after the establishment or resumption of the RRC connection is completed, and can decide whether to release the RRC connection based on the measurement results.

[0062] By way of example and not limitation, gNB 2 may perform steps 802 and 803. In step 802, gNB 2 decides to release the RRC connection based on the provided measurement results. In step 803, gNB 2 sends an RRC release message to NCR 1 (NCR-MT 12). The RRC release message may indicate that the rejection of the RRC connection establishment or resumption is due to insufficient received power or received quality level in the cell.

[0063] Additionally or alternatively, the RRC release message may indicate an access restriction period. This RRC release message may be similar to the RRC release message described in the second embodiment. Specifically, if the received power (e.g., RSRP) or received quality (e.g., RSRQ) level in the cell is lower than a threshold, the RRC release message causes the NCR 1 (NCR-MT 12) to not initiate a random access procedure to the cell until at least the access restriction period has elapsed. The RRC release message may further indicate the threshold. The NCR 1 (NCR-MT 12) may perform threshold determination for both the received power (e.g., RSRP) level and the received quality (e.g., RSRQ) level. In this case, the RRC release message may indicate two thresholds, one for the received power (e.g., RSRP) level and the other for the received quality (e.g., RSRQ) level. If the received power or received quality level in the cell is lower than a threshold, the NCR 1 (NCR-MT 12) operates not to initiate a random access procedure to the cell until at least the access restriction period has elapsed. The access restriction period may be one hour or more. For example, the access restriction period may indicate one of 1 hour, 2 hours, 4 hours, 8 hours, 16 hours, 1 day, 3 days, or 7 days.

[0064] According to the operations of steps 802 and 803, gNB 2 can release the RRC connection of NCR 1 whose control link quality is low (and therefore whose backhaul link quality is also expected to be low) and control NCR 1 not to attempt cell access until the quality recovers or the access restriction period has elapsed. This can contribute to restricting access to the cell of NCR 1 (NCR-MT 12) whose control link quality is low.

[0065] Fifth Embodiment This embodiment relates to cell reselection. The NCR 11 is assumed to be stationary and has no mobility. As described above, the NCR-MT 12 may support functions defined for RedCap UEs. Therefore, in this embodiment, the NCR-MT 12 supports functions that are the same as or similar to the relaxed measurement (or relaxed monitoring for cell reselection) defined for RedCap UEs in 3GPP Release 17.

[0066] More specifically, the NCR-MT 12 may support the same or similar function as the Relaxed measurement criterion for a stationary RedCap UE. The threshold parameter SSearchDeltaP-Stationary for the Relaxed measurement criterion for a stationary RedCap UE may be reused. Alternatively, a threshold parameter different from SSearchDeltaP-Stationary (e.g., SSearchDeltaP-Stationary2) may be newly defined.

[0067] Additionally or alternatively, the NCR-MT 12 may support functionality identical to or similar to the Relaxed measurement criterion for a stationary RedCap UE not at the cell edge. SearchThresholdP2 may be reused. Alternatively, S SearchThresholdP2 threshold parameters (e.g., S SearchThresholdP3 ) may be newly defined.

[0068] Other Embodiments In one implementation, similar to the Integrated Access and Backhaul (IAB) MT, the NCR-MT 12 ignores cellBarred, cellReservedForOperatorUse, cellReservedForFutureUse, and intraFreqReselection, i.e., the NCR-MT 12 treats intraFreqReselection as if it were set to allowed.

[0069] Additionally or alternatively, in some implementations, NCR-MT 12 ignores cellReservedForOtherUse for cell barring decisions. In other words, if NCR-MT 12 supports a Non-Public Network (NPN), NCR-MT 12 considers cellReservedForOtherUse for NPN-only cell decisions.

[0070] Next, exemplary configurations of the gNB 2 and the NCR-MT 12 according to the above-described embodiments will be described below. FIG. 9 is a block diagram showing an exemplary configuration of the gNB 2 according to the above-described embodiments. Referring to FIG. 9, the gNB 2 includes a Radio Frequency (RF) transceiver 901, a network interface 903, a processor 904, and a memory 905. The RF transceiver 901 performs analog RF signal processing for communication with UEs. The RF transceiver 901 may include multiple transceivers. The RF transceiver 901 is coupled to an antenna array 902 and a processor 904. The RF transceiver 901 receives modulation symbol data from the processor 904, generates a transmit RF signal, and provides the transmit RF signal to the antenna array 902. The RF transceiver 901 also generates a baseband receive signal based on the receive RF signal received by the antenna array 902 and provides the baseband receive signal to the processor 904. The RF transceiver 901 may include an analog beamformer circuit for beamforming. The analog beamformer circuitry includes, for example, multiple phase shifters and multiple power amplifiers.

[0071] The network interface 903 is used to communicate with network nodes (e.g., other RAN nodes, and control plane nodes and user plane nodes of the core network), and may include, for example, a network interface card (NIC) compliant with the IEEE 802.3 series.

[0072] The processor 904 performs digital baseband signal processing (data plane processing) and control plane processing for wireless communication. The processor 904 may include multiple processors. For example, the processor 904 may include a modem processor (e.g., a Digital Signal Processor (DSP)) that performs digital baseband signal processing and a protocol stack processor (e.g., a Central Processing Unit (CPU) or a Micro Processing Unit (MPU)) that performs control plane processing.

[0073] For example, digital baseband signal processing by the processor 904 may include signal processing for the Service Data Adaptation Protocol (SDAP) layer, Packet Data Convergence Protocol (PDCP) layer, Radio Link Control (RLC) layer, Medium Access Control (MAC) layer, and Physical (PHY) layer. Control plane processing by the processor 904 may also include processing of Non-Access Stratum (NAS) messages, RRC messages, Medium Access Control (MAC) Control Elements (CEs), and Downlink Control Information (DCI). Control plane processing by the processor 904 may also include processing of application layer signaling protocols such as XnAP, F1AP, and NGAP.

[0074] The processor 904 may include a digital beamformer module for beamforming, which may include a Multiple Input Multiple Output (MIMO) encoder and precoder.

[0075] The memory 905 is configured by a combination of volatile memory and non-volatile memory. The volatile memory is, for example, Static Random Access Memory (SRAM), Dynamic RAM (DRAM), or a combination thereof. The non-volatile memory is, for example, Mask Read Only Memory (MROM), Electrically Erasable Programmable ROM (EEPROM), flash memory, or a hard disk drive, or any combination thereof. The memory 905 may include storage located remotely from the processor 904. In this case, the processor 904 may access the memory 905 via the network interface 903 or an I / O interface.

[0076] The memory 905 may store one or more software modules (computer programs) 906 including instructions and data for performing the processing by the gNB 2 described in the above embodiments. In some implementations, the processor 904 may be configured to read and execute the software modules 906 from the memory 905 to perform the processing by the gNB 2 described in the above embodiments.

[0077] Note that if gNB 2 is a gNB-CU or CU-CP, gNB 2 may not include RF transceiver 901 (and antenna array 902).

[0078] 10 is a block diagram showing an example of the configuration of the NCR-MT 12. Referring to FIG.

[0079] The processor 1001 may include multiple processors. The processor 1001 performs processing related to the NCR-MT 12 described in the above embodiments. The processor 1802 performs digital baseband signal processing (data plane processing) and control plane processing for wireless communication. For example, the processor 1001 may include a modem processor (e.g., a Digital Signal Processor (DSP)) that performs digital baseband signal processing and a protocol stack processor (e.g., a Central Processing Unit (CPU) or a Micro Processing Unit (MPU)) that performs control plane processing. The digital baseband signal processing may include signal processing of the RLC, MAC, and PHY layers. The control plane processing may include processing of MAC CEs and DCIs.

[0080] The memory 1002 is configured by a combination of volatile memory and non-volatile memory. The memory 1002 may include multiple physically independent memory devices. The volatile memory is, for example, SRAM or DRAM, or a combination thereof. The non-volatile memory is MROM, EEPROM, flash memory, or a hard disk drive, or any combination thereof. For example, the memory 1002 may include an external memory device accessible from the processor 1001. The memory 1002 may also include an internal memory device integrated within the processor 1001. Furthermore, the memory 1002 may include memory within a Universal Integrated Circuit Card (UICC).

[0081] The memory 1002 may store one or more software modules (computer programs) 1003 including instructions and data for performing the processing of the NCR-MT 12 described in the above-described embodiments. In some implementations, the processor 1001 may be configured to read and execute the software modules 1003 from the memory 1002 to perform the processing of the NCR-MT 12 described in the above-described embodiments.

[0082] As described with reference to FIGS. 9 and 10 , each of the processors included in the gNB 2 and NCR-MT 12 according to the above-described embodiments can execute one or more programs including instructions for causing a computer to perform the algorithms described with reference to the drawings. The programs include instructions (or software code) that, when loaded into a computer, cause the computer to perform one or more functions described in the embodiments. The programs may be stored on a non-transitory computer-readable medium or a tangible storage medium. By way of example and not limitation, computer-readable media or tangible storage media include random-access memory (RAM), read-only memory (ROM), flash memory, solid-state drive (SSD) or other memory technology, CD-ROM, digital versatile disk (DVD), Blu-ray® disk or other optical disk storage, magnetic cassette, magnetic tape, magnetic disk storage, or other magnetic storage device. The programs may also be transmitted on a transitory computer-readable medium or communication medium. By way of example and not limitation, transitory computer-readable media or communication media include electrical, optical, acoustic, or other forms of propagated signals.

[0083] The above-described embodiments are merely examples of application of the technical ideas obtained by the inventors of the present invention. In other words, the technical ideas are not limited to the above-described embodiments, and various modifications are possible.

[0084] For example, some or all of the above embodiments can be described as, but are not limited to, the following supplementary notes.

[0085] (Supplementary Note 1) A Network Controlled Repeater (NCR) comprising: a repeater unit comprising a Radio Frequency (RF) component and configured to amplify and forward an RF signal; and a controller coupled to the repeater unit and configured to provide an NCR mobile termination (MT), wherein the controller is configured to use an NCR-MT-specific second minimum required received power or minimum required quality level at a cell to determine whether the cell satisfies a cell selection criterion, the second minimum required received power or minimum required quality level being different from a first minimum required received power or minimum required quality level at the cell for normal User Equipment (UE) that is not NCR-MT. (Supplementary Note 2) The NCR according to Supplementary Note 1, wherein the second minimum required received power or minimum required quality level is greater than the first minimum required received power or minimum required quality level. (Supplementary Note 3) The NCR according to Supplementary Note 1 or 2, wherein the controller is configured to receive cell selection information broadcasted in the cell, the cell selection information including a first parameter and a second parameter, the first parameter representing the first minimum required received power or minimum required quality level, and the second parameter representing the second minimum required received power or minimum required quality level. (Supplementary Note 4) The NCR according to Supplementary Note 1 or 2, wherein the controller is configured to receive cell selection information broadcasted in the cell, the cell selection information including a first parameter and a third parameter, the first parameter representing the first minimum required received power or minimum required quality level, and the third parameter being used by the controller to derive the second minimum required received power or minimum required quality level from the first parameter.(Supplementary Note 5) The NCR according to Supplementary Note 1 or 2, wherein the controller is configured to receive cell selection information broadcast in the cell, the cell selection information including a first parameter, the first parameter representing the first minimum required received power or minimum required quality level, and the controller is configured to derive the second minimum required received power or minimum required quality level from the first parameter. (Supplementary Note 6) The NCR according to any one of Supplements 1 to 5, wherein the repeater unit is configured to forward the RF signals between a Radio Access Network (RAN) node and User Equipments (UEs), and the NCR-MT is adapted to communicate with the RAN node via a control link to exchange control information. (Supplementary Note 7) A Radio Access Network (RAN) node comprising: means for broadcasting cell selection information in a cell, the cell selection information including a first parameter and further including a second parameter or a third parameter, the first parameter representing a first minimum required received power or minimum required quality level in the cell used for cell selection by normal User Equipment (UE) that is not a Network Controlled Repeater (NCR) mobile termination (MT), the second parameter representing a second minimum required received power or minimum required quality level in the cell used for cell selection by the NCR-MT, and the third parameter being used by the NCR-MT to determine the second minimum required received power or minimum required quality level from the first parameter. (Supplementary Note 8) The RAN node according to Supplementary Note 7, wherein the second minimum required received power or minimum required quality level is greater than the first minimum required received power or minimum required quality level. (Supplementary Note 9) The RAN node according to Supplementary Note 7 or 8, wherein the NCR-MT is a mobile termination function in an NCR configured to forward Radio Frequency (RF) signals between the RAN node and UEs.(Supplementary Note 10) A method performed by a Network Controlled Repeater (NCR), comprising using a second minimum required received power or minimum required quality level specific to NCR-MT in a cell to determine whether the cell satisfies a cell selection criterion, wherein the second minimum required received power or minimum required quality level is different from a first minimum required received power or minimum required quality level in the cell for normal User Equipment (UE) that is not NCR-MT. (Supplementary Note 11) A method performed by a Radio Access Network (RAN) node, comprising broadcasting cell selection information in a cell, the cell selection information including a first parameter and further including a second parameter or a third parameter, the first parameter representing a first minimum required received power or minimum required quality level in the cell used for cell selection by a normal User Equipment (UE) that is not a Network Controlled Repeater (NCR) mobile termination (MT), the second parameter representing a second minimum required received power or minimum required quality level in the cell used for cell selection by the NCR-MT, and the third parameter being used by the NCR-MT to determine the second minimum required received power or minimum required quality level from the first parameter. (Supplementary Note 12) A program for causing a computer to perform a method for a Network Controlled Repeater (NCR), the method comprising using a second minimum required received power or minimum required quality level specific to an NCR-MT in a cell that is different from a first minimum required received power or minimum required quality level in the cell for normal User Equipment (UE) that is not an NCR mobile termination (MT), to determine whether the cell satisfies a cell selection criterion.(Supplementary Note 13) A program for causing a computer to perform a method for a Radio Access Network (RAN) node, the method comprising controlling the RAN node to broadcast cell selection information in a cell, the cell selection information including a first parameter and further including a second parameter or a third parameter, the first parameter representing a first minimum required received power or minimum required quality level in the cell used for cell selection by normal User Equipment (UE) that is not a Network Controlled Repeater (NCR) mobile termination (MT), the second parameter representing a second minimum required received power or minimum required quality level in the cell used for cell selection by the NCR-MT, and the third parameter being used by the NCR-MT to determine the second minimum required received power or minimum required quality level from the first parameter. (Supplementary Note 14) A Network Controlled Repeater (NCR) comprising: a repeater unit having a Radio Frequency (RF) component and configured to amplify and forward RF signals between a Radio Access Network (RAN) node and User Equipments (UEs); and a controller coupled to the repeater unit and configured to communicate with the RAN node via a control link to exchange control information, wherein the controller is configured to: receive a Radio Resource Control (RRC) release message from the RAN node requesting release of an RRC connection in a cell and indicating an access restriction period; and if a received power or reception quality level in the cell is lower than a threshold, not initiate a random access procedure to the cell until at least the access restriction period has elapsed. (Supplementary Note 15) The NCR according to Supplementary Note 14, wherein the access restriction period is one hour or more.(Supplementary Note 16) The NCR according to Supplementary Note 14 or 15, wherein the RRC release message further indicates the threshold. (Supplementary Note 17) The NCR according to any one of Supplementary Notes 14 to 16, wherein the RRC release message indicates that the cause of the release of the RRC connection is a decrease or insufficiency of a received power or a received quality level in the cell. (Supplementary Note 18) A Radio Access Network (RAN) node, comprising: means for determining release of a Radio Resource Control (RRC) connection in the cell for the NCR in response to a decrease or insufficiency of a received power or a received quality level of a Network Controlled Repeater (NCR) in the cell; and means for sending an RRC release message to the NCR, indicating an access restriction period, wherein the RRC release message causes the NCR not to initiate a random access procedure to the cell until at least the access restriction period has elapsed, if the received power or the received quality level in the cell is lower than a threshold. (Supplementary Note 19) The RAN node according to Supplementary Note 18, wherein the access restriction period is one hour or more. (Supplementary Note 20) The RAN node according to Supplementary Note 18 or 19, wherein the RRC release message further indicates the threshold. (Supplementary Note 21) The RAN node according to any one of Supplements 18 to 20, wherein the RRC release message indicates that the release of the RRC connection is caused by a decrease or insufficiency of a received power or a received quality level in the cell. (Supplementary Note 22) A method performed by a Network Controlled Repeater (NCR), comprising: receiving an RRC release message from a Radio Access Network (RAN) node requesting release of a Radio Resource Control (RRC) connection in a cell and indicating an access restriction period; and if the received power or received quality level in the cell is lower than a threshold, not initiating a random access procedure to the cell until at least the access restriction period has elapsed.(Supplementary Note 23) A method performed by a Radio Access Network (RAN) node, comprising: in response to a decrease or lack of received power or received quality level of a Network Controlled Repeater (NCR) in a cell, deciding to release a Radio Resource Control (RRC) connection in the cell for the NCR, and sending an RRC release message to the NCR indicating an access restriction period, the RRC release message causing the NCR to not initiate a random access procedure to the cell until at least the access restriction period has elapsed if the received power or received quality level in the cell is lower than a threshold. (Supplementary Note 24) A program causing a computer to perform a method for a Network Controlled Repeater (NCR), the method comprising: receiving a Radio Resource Control (RRC) release message from a radio access network node requesting release of an RRC connection in a cell and indicating an access restriction period; and if a received power or a received quality level in the cell is lower than a threshold, not initiating a random access procedure to the cell until at least the access restriction period has elapsed. (Supplementary Note 25) A program for causing a computer to perform a method for a Radio Access Network (RAN) node, the method comprising: determining to release a Radio Resource Control (RRC) connection in a cell for a Network Controlled Repeater (NCR) in response to a decrease or lack of a received power or a received quality level of the NCR in the cell, and sending an RRC release message to the NCR indicating an access restriction period, the RRC release message causing the NCR to not initiate a random access procedure to the cell until at least the access restriction period has elapsed if the received power or received quality level in the cell is lower than a threshold.(Supplementary Note 26) A Network Controlled Repeater (NCR), comprising: a repeater unit having a Radio Frequency (RF) component and configured to amplify and forward RF signals between a Radio Access Network (RAN) node and User Equipments (UEs); and a controller coupled to the repeater unit and configured to communicate with the RAN node via a control link to exchange control information, wherein the controller is configured to send an RRC Setup or Resume Request message to request establishment or resumption of a Radio Resource Control (RRC) connection in a cell, the RRC Setup or Resume Request message indicating measurement results for the cell that were recorded when the NCR was in RRC_IDLE or RRC_INACTIVE. (Supplementary Note 27) The NCR of Supplementary Note 26, wherein the controller is configured to: receive an RRC rejection message after transmitting the RRC setup or resumption request message, the RRC rejection message indicating a rejection of the establishment or resumption of the RRC connection and indicating an access restriction period; and if a received power or a received quality level at the cell is lower than a threshold, not initiate a random access procedure to the cell until at least the access restriction period has elapsed. (Supplementary Note 28) The NCR of Supplementary Note 27, wherein the access restriction period is one hour or more. (Supplementary Note 29) The NCR of Supplementary Note 27 or 28, wherein the RRC rejection message further indicates the threshold. (Supplementary Note 30) The NCR of any one of Supplements 27 to 29, wherein the RRC rejection message indicates that the rejection of the establishment or resumption of the RRC connection is due to insufficient received power or received quality level at the cell.(Supplementary Note 31) A Radio Access Network (RAN) node comprising: means for receiving, from a Network Controlled Repeater (NCR), an RRC SETUP or RESUME REQUEST message requesting the establishment or resumption of a Radio Resource Control (RRC) connection in a cell, the RRC SETUP or RESUME REQUEST message indicating measurement results for the cell that were recorded when the NCR was in RRC_IDLE or RRC_INACTIVE. (Supplementary Note 32) The RAN node according to Supplementary Note 31, further comprising means for sending an RRC REJECT message to the NCR indicating a rejection of the RRC connection establishment or resumption and indicating an access restriction period if it is determined based on the measurement results for the cell that a received power or a received quality level of the NCR in the cell is insufficient, the RRC REJECT message causing the NCR to not initiate a random access procedure to the cell until at least the access restriction period has elapsed if the received power or received quality level in the cell is lower than a threshold. (Supplementary Note 33) The RAN node according to Supplementary Note 32, wherein the access restriction period is equal to or greater than one hour. (Supplementary Note 34) The RAN node according to Supplementary Note 32 or 33, wherein the RRC rejection message further indicates the threshold. (Supplementary Note 35) The RAN node according to any one of Supplements 32 to 34, wherein the RRC rejection message indicates that the rejection of the RRC connection establishment or resumption is due to insufficient received power or received quality level in the cell. (Supplementary Note 36) A method performed by a Network Controlled Repeater (NCR), comprising transmitting an RRC Setup or Resumption Request message to request establishment or resumption of a Radio Resource Control (RRC) connection in a cell, the RRC Setup or Resumption Request message indicating measurement results for the cell that were recorded when the NCR was in RRC_IDLE or RRC_INACTIVE.(Supplementary Note 37) A method performed by a Radio Access Network (RAN) node, comprising receiving, from a Network Controlled Repeater (NCR), an RRC Setup or Resume Request message requesting establishment or resumption of a Radio Resource Control (RRC) connection in a cell, the RRC Setup or Resume Request message indicating measurements of the cell that were recorded when the NCR was RRC_IDLE or RRC_INACTIVE. (Supplementary Note 38) A program for causing a computer to perform a method for a Network Controlled Repeater (NCR), the method comprising sending an RRC Setup or Resume Request message requesting establishment or resumption of a Radio Resource Control (RRC) connection in a cell, the RRC Setup or Resume Request message indicating measurements of the cell that were recorded when the NCR was RRC_IDLE or RRC_INACTIVE. (Supplementary Note 39) A program for causing a computer to perform a method for a Radio Access Network (RAN) node, the method comprising receiving, from a Network Controlled Repeater (NCR), a Radio Resource Control (RRC) Setup or Resumption Request message requesting establishment or resumption of an RRC connection in a cell, the RRC Setup or Resumption Request message indicating measurements of the cell recorded when the NCR was in RRC_IDLE or RRC_INACTIVE.(Supplementary Note 40) A Network Controlled Repeater (NCR), comprising: a repeater unit having a Radio Frequency (RF) component and configured to amplify and forward RF signals between a Radio Access Network (RAN) node and User Equipments (UEs); and a controller coupled to the repeater unit and configured to communicate with the RAN node via a control link to exchange control information, wherein the controller is configured to send a Radio Resource Control (RRC) Setup or Resumption Complete message indicating completion of establishment or resumption of an RRC connection in a cell, the RRC Setup or Resumption Complete message indicating measurement results for the cell that were recorded when the NCR was RRC_IDLE or RRC_INACTIVE. (Supplementary Note 41) The NCR of Supplementary Note 40, wherein the controller is configured to: receive an RRC release message after transmitting the RRC setup or resumption complete message, the RRC release message indicating release of the RRC connection and indicating an access restriction period; and if a received power or a received quality level in the cell is lower than a threshold, not initiate a random access procedure to the cell until at least the access restriction period has elapsed. (Supplementary Note 42) The NCR of Supplementary Note 41, wherein the access restriction period is one hour or more. (Supplementary Note 43) The NCR of Supplementary Note 41 or 42, wherein the RRC release message further indicates the threshold. (Supplementary Note 44) The NCR of any one of Supplements 41 to 43, wherein the RRC release message indicates that the release of the RRC connection is due to insufficient received power or received quality level in the cell.(Supplementary Note 45) A Radio Access Network (RAN) node comprising: means for receiving, from a Network Controlled Repeater (NCR), an RRC SETUP OR RESULT COMPLETE message indicating completion of establishment or resumption of a Radio Resource Control (RRC) connection in a cell, wherein the RRC SETUP OR RESULT COMPLETE message indicates measurement results for the cell that were recorded when the NCR was in RRC_IDLE or RRC_INACTIVE. (Supplementary Note 46) The RAN node according to Supplementary Note 45, further comprising means for sending an RRC release message to the NCR, when it is determined based on the measurement results for the cell that a received power or a received quality level of the NCR in the cell is insufficient, indicating release of the RRC connection and indicating an access restriction period, wherein the RRC release message causes the NCR to not initiate a random access procedure to the cell until at least the access restriction period has elapsed, if the received power or received quality level in the cell is lower than a threshold. (Supplementary Note 47) The RAN node according to Supplementary Note 46, wherein the access restriction period is one hour or more. (Supplementary Note 48) The RAN node according to Supplementary Note 46 or 47, wherein the RRC release message further indicates the threshold. (Supplementary Note 49) The RAN node according to any one of Supplements 46 to 48, wherein the RRC release message indicates that the cause of the release of the RRC connection is insufficient received power or received quality level in the cell. (Supplementary Note 50) A method performed by a Network Controlled Repeater (NCR), comprising transmitting an RRC Setup or Resumption Complete message indicating completion of establishment or resumption of a Radio Resource Control (RRC) connection in a cell, wherein the RRC Setup or Resumption Complete message indicates measurement results for the cell that were recorded when the NCR was RRC_IDLE or RRC_INACTIVE.(Supplementary Note 51) A method performed by a Radio Access Network (RAN) node, comprising receiving, from a Network Controlled Repeater (NCR), an RRC Setup or Resumption Complete message indicating completion of establishment or resumption of a Radio Resource Control (RRC) connection in a cell, wherein the RRC Setup or Resumption Complete message indicates measurements of the cell that were recorded when the NCR was RRC_IDLE or RRC_INACTIVE. (Supplementary Note 52) A program for causing a computer to perform a method for a Network Controlled Repeater (NCR), comprising sending an RRC Setup or Resumption Complete message indicating completion of establishment or resumption of a Radio Resource Control (RRC) connection in a cell, wherein the RRC Setup or Resumption Complete message indicates measurements of the cell that were recorded when the NCR was RRC_IDLE or RRC_INACTIVE. (Supplementary Note 53) A program for causing a computer to perform a method for a Radio Access Network (RAN) node, the method comprising receiving, from a Network Controlled Repeater (NCR), an RRC Setup or Resumption Complete message indicating completion of establishment or resumption of a Radio Resource Control (RRC) connection in a cell, the RRC Setup or Resumption Complete message indicating measurement results for the cell that were recorded when the NCR was in RRC_IDLE or RRC_INACTIVE.

[0086] This application claims priority based on Japanese Patent Application No. 2022-155435, filed on September 28, 2022, the disclosure of which is incorporated herein in its entirety.

[0087] 1 NCR 2 gNB 3 UE 11 NCR-Fwd 12 NCR-MT 904 Processor 905 Memory 906 Module 1001 Processor 1002 Memory 1003 Module

Claims

1. A Network Controlled Repeater (NCR), comprising: a repeater unit including a Radio Frequency (RF) component and configured to amplify and forward an RF signal; a controller coupled to the repeater unit and configured to provide NCR mobile termination (MT); Equipped with The controller is configured to use a second NCR-MT specific minimum required received power or minimum required quality level at the cell to determine whether the cell satisfies a cell selection criterion; The second minimum required received power or minimum required quality level is different from the first minimum required received power or minimum required quality level in the cell for normal User Equipment (UE) that is not NCR-MT. NCR.

2. The controller is configured to receive cell selection information broadcast in the cell; The cell selection information includes a first parameter and a second parameter; the first parameter represents the first minimum required received power or minimum required quality level; the second parameter represents the second minimum required received power or minimum required quality level; The NCR of claim 1.

3. The controller is configured to receive cell selection information broadcast in the cell; the cell selection information includes a first parameter and a third parameter; the first parameter represents the first minimum required received power or minimum required quality level; the third parameter is used by the controller to derive the second minimum required received power or minimum required quality level from the first parameter. The NCR of claim 1.

4. The controller is configured to receive cell selection information broadcast in the cell; the cell selection information includes a first parameter; the first parameter represents the first minimum required received power or minimum required quality level; the controller is configured to derive the second minimum required received power or minimum required quality level from the first parameter. The NCR of claim 1.

5. 1. A Radio Access Network (RAN) node, comprising: means for broadcasting cell selection information in a cell; The cell selection information includes a first parameter and further includes a second parameter or a third parameter; The first parameter represents a first minimum required received power or a minimum required quality level in the cell used for cell selection by a normal User Equipment (UE) that is not a Network Controlled Repeater (NCR) mobile termination (MT); The second parameter represents a second minimum required received power or a minimum required quality level in the cell used for cell selection by the NCR-MT; The third parameter is used by the NCR-MT to determine the second minimum required received power or minimum required quality level from the first parameter. RAN node.

6. A method performed by a Network Controlled Repeater (NCR), comprising: using a second minimum required received power or minimum required quality level specific to an NCR-MT in a cell to determine whether the cell satisfies a cell selection criterion; The second minimum required received power or minimum required quality level is different from the first minimum required received power or minimum required quality level in the cell for normal User Equipment (UE) that is not NCR-MT. method.

7. 1. A method performed by a Radio Access Network (RAN) node, comprising: broadcasting cell selection information in the cell; The cell selection information includes a first parameter and further includes a second parameter or a third parameter; The first parameter represents a first minimum required received power or a minimum required quality level in the cell used for cell selection by a normal User Equipment (UE) that is not a Network Controlled Repeater (NCR) mobile termination (MT); The second parameter represents a second minimum required received power or a minimum required quality level in the cell used for cell selection by the NCR-MT; The third parameter is used by the NCR-MT to determine the second minimum required received power or minimum required quality level from the first parameter. method.

8. A Network Controlled Repeater (NCR), comprising: a repeater unit comprising a Radio Frequency (RF) component and configured to amplify and forward RF signals between a Radio Access Network (RAN) node and User Equipments (UEs); a controller coupled to the repeater unit and configured to communicate with the RAN node over a control link to exchange control information; Equipped with The controller: receiving a Radio Resource Control (RRC) release message from the RAN node requesting release of an RRC connection in a cell and indicating an access restriction period; If the reception power or reception quality level in the cell is lower than a threshold, a random access procedure to the cell is not initiated until at least the access restriction period has elapsed. It is configured as follows: NCR.

9. 1. A Radio Access Network (RAN) node, comprising: means for determining release of a Radio Resource Control (RRC) connection in a cell for a Network Controlled Repeater (NCR) in response to a decrease or lack of a reception power or reception quality level of said NCR in said cell; means for sending an RRC release message indicating an access restriction period to the NCR; The RRC release message causes the NCR to not initiate a random access procedure to the cell if the received power or received quality level in the cell is below a threshold value until at least the access restriction period has elapsed. RAN node.

10. A method performed by a Network Controlled Repeater (NCR), comprising: receiving a Radio Resource Control (RRC) release message from a Radio Access Network (RAN) node requesting release of an RRC connection in the cell and indicating an access restriction period; and If a reception power or reception quality level in the cell is lower than a threshold, not initiating a random access procedure to the cell until at least the access restriction period has elapsed; A method for providing the above.

11. 1. A method performed by a Radio Access Network (RAN) node, comprising: determining a release of a Radio Resource Control (RRC) connection in the cell for a Network Controlled Repeater (NCR) in response to a decrease or deficiency in a reception power or reception quality level of the NCR in the cell and sending an RRC release message to the NCR indicating an access restriction period; The RRC release message causes the NCR to not initiate a random access procedure to the cell if the received power or received quality level in the cell is below a threshold value until at least the access restriction period has elapsed. method.

12. A Network Controlled Repeater (NCR), comprising: a repeater unit comprising a Radio Frequency (RF) component and configured to amplify and forward RF signals between a Radio Access Network (RAN) node and User Equipments (UEs); a controller coupled to the repeater unit and configured to communicate with the RAN node over a control link to exchange control information; Equipped with The controller is configured to send a Radio Resource Control (RRC) SETUP or RESUME REQUEST message to request establishment or resumption of an RRC connection in a cell; The RRC SETUP or RESUME REQUEST message indicates measurement results of the cell recorded when the NCR is RRC_IDLE or RRC_INACTIVE. NCR.

13. The controller: receiving an RRC rejection message indicating a rejection of the establishment or resumption of the RRC connection and indicating an access restriction period after transmitting the RRC setup or resumption request message; If the reception power or reception quality level in the cell is lower than a threshold, a random access procedure to the cell is not initiated until at least the access restriction period has elapsed. It is configured as follows: The NCR of claim 12.

14. 1. A Radio Access Network (RAN) node, comprising: means for receiving an RRC setup or resumption request message from a Network Controlled Repeater (NCR) for requesting establishment or resumption of a Radio Resource Control (RRC) connection in a cell; The RRC SETUP or RESUME REQUEST message indicates measurement results of the cell recorded when the NCR is RRC_IDLE or RRC_INACTIVE. RAN node.

15. If it is determined based on the measurement result of the cell that the reception power or reception quality level of the NCR in the cell is insufficient, a means for sending an RRC rejection message to the NCR indicating a rejection of the establishment or resumption of the RRC connection and indicating an access restriction period, The RRC rejection message causes the NCR to not initiate a random access procedure to the cell if the received power or received quality level in the cell is below a threshold value until at least the access restriction period has elapsed.

15. The RAN node of claim 14.

16. A method performed by a Network Controlled Repeater (NCR), comprising: transmitting an RRC SETUP or RESUME REQUEST message to request establishment or resumption of a Radio Resource Control (RRC) connection in a cell; The RRC SETUP or RESUME REQUEST message indicates measurement results of the cell recorded when the NCR is RRC_IDLE or RRC_INACTIVE. method.

17. 1. A method performed by a Radio Access Network (RAN) node, comprising: receiving an RRC setup or resumption request message from a Network Controlled Repeater (NCR) for requesting establishment or resumption of a Radio Resource Control (RRC) connection in a cell; The RRC SETUP or RESUME REQUEST message indicates measurement results of the cell recorded when the NCR is RRC_IDLE or RRC_INACTIVE. method.

18. A Network Controlled Repeater (NCR), comprising: a repeater unit comprising a Radio Frequency (RF) component and configured to amplify and forward RF signals between a Radio Access Network (RAN) node and User Equipments (UEs); a controller coupled to the repeater unit and configured to communicate with the RAN node over a control link to exchange control information; Equipped with The controller: configured to transmit an RRC setup or resumption complete message indicating completion of establishment or resumption of a Radio Resource Control (RRC) connection in the cell; The RRC setup or resumption complete message indicates the measurement results of the cell recorded when the NCR was RRC_IDLE or RRC_INACTIVE. NCR.

19. The controller: receiving an RRC release message indicating release of the RRC connection and indicating an access restriction period after transmitting the RRC setup or resumption complete message; If the reception power or reception quality level in the cell is lower than a threshold, a random access procedure to the cell is not initiated until at least the access restriction period has elapsed. It is configured as follows: The NCR of claim 18.

20. 1. A Radio Access Network (RAN) node, comprising: means for receiving an RRC setup or resumption complete message from a Network Controlled Repeater (NCR), indicating completion of establishment or resumption of a Radio Resource Control (RRC) connection in a cell; The RRC setup or resumption complete message indicates the measurement results of the cell recorded when the NCR is RRC_IDLE or RRC_INACTIVE. RAN node.

21. If it is determined that the reception power or reception quality level of the NCR in the cell is insufficient based on the measurement result of the cell, an RRC release message indicating release of the RRC connection and indicating an access restriction period is sent to the NCR, The RRC release message causes the NCR to not initiate a random access procedure to the cell if the received power or received quality level in the cell is below a threshold value until at least the access restriction period has elapsed.

21. The RAN node of claim 20.

22. A method performed by a Network Controlled Repeater (NCR), comprising: transmitting an RRC setup or resumption complete message indicating completion of establishment or resumption of a Radio Resource Control (RRC) connection in the cell; The RRC setup or resumption complete message indicates the measurement results of the cell recorded when the NCR was RRC_IDLE or RRC_INACTIVE. method.

23. 1. A method performed by a Radio Access Network (RAN) node, comprising: receiving an RRC setup or resumption complete message from a Network Controlled Repeater (NCR) indicating completion of establishment or resumption of a Radio Resource Control (RRC) connection in a cell; The RRC setup or resumption complete message indicates the measurement results of the cell recorded when the NCR is RRC_IDLE or RRC_INACTIVE. method.