Base station and radio communication method

Abstract

Provided is a base station comprising: a transmission / reception unit that transmits and receives a radio signal to and from a terminal to be simultaneously connected to the base station and another base station; and a control unit that requests the other base station to change the base station to which the terminal is to be connected, wherein the control unit requests, from the other base station, the number of counter values for deriving a necessary security key each time the terminal changes the connection with the base station.

Description

Base station and wireless communication method

[0001] The present disclosure relates to a base station and a wireless communication method that supports subsequent mobility.

[0002] The 3rd Generation Partnership Project (3GPP) is developing specifications for the 5th generation mobile communication system (5G, also known as New Radio (NR) or Next Generation (NG)), and is also developing specifications for the next generation of mobile communication systems, known as Beyond 5G, 5G Evolution, or 6G.

[0003] When a User Equipment (UE) performs a Conditional PSCell Change (CPC) to change the primary / secondary cell (PSCell) formed by a Secondary Node (SN), it is necessary to repeatedly acquire and discard cell configuration information. To reduce this acquisition and discarding of configuration information, a method has been proposed in which the UE retains cell configuration information (also known as Secondary Cell Group (SCG) selective activation, or SCG selective activation may be interpreted as selective activation). SCG selective activation can achieve fast CPC and reduce signaling overhead.

[0004] With the proposal of SCG selective activation, its security has also been discussed. A UE acquires in advance from a Master node (MN) a counter value (SN Counter value, hereinafter simply referred to as an SN Counter; the SN Counter may also be read as an sk counter) used to derive a security key required each time it connects to an SN. The SN Counter is set for each SN. When performing CPC, a UE can securely connect to an SN by deriving a security key from an unused SN Counter corresponding to the SN to which it is connected (Non-Patent Document 1).

[0005] “LS on Security Solution for Selective SCG”, S3-233200, 3GPP TSG-SA3 Meeting #111, Berlin, Germany, 22 -26 May 2023

[0006] SCG selective activation is also called subsequent mobility because it is a mobility that does not require Radio Resource Control (RRC) reconfiguration with the base station (gNodeB, gNB) every time the UE changes cells. However, even with subsequent mobility, if the UE runs out of SN Counter due to repeated mobility, it needs to reacquire the SN Counter from the MN.

[0007] However, when the number of SN Counters acquired by a UE is determined by the MN, there is a problem that the SN has no room for involvement in the MN's decision. Regarding changes in the PSCell to which a UE connects, the SN has more detailed information than the MN, and the number of SN Counters determined by the MN may not be appropriate for the actual mobility situation. In addition, when such MN-led mobility is performed, there is a problem that the SN cannot grasp from which SN Counter the UE derives the security key.

[0008] Therefore, the present disclosure has been made in consideration of such circumstances, and aims to provide a base station and a wireless communication method that can participate in MN-led mobility with respect to the SN Counter acquired by the UE.

[0009] One aspect of the disclosure is a base station (gNB100B) comprising: a transceiver unit (transceiver unit 110) that transmits and receives radio signals between the base station and a terminal (UE200) that is simultaneously connected to the base station and another base station (gNB100A); and a control unit (control unit 150) that requests the other base station to change the base station to which the terminal is connected, wherein the control unit requests the other base station the number of counter values ​​for deriving the required security key each time the terminal changes its connection with the base station.

[0010] One aspect of the disclosure is a base station (gNB100B) comprising: a transceiver unit (transceiver unit 110) that transmits and receives radio signals between a terminal (UE200) that is simultaneously connected to the base station and another base station (gNB100A); and a control unit (control unit 150) that requests the other base station to change the base station to which the terminal is connected, wherein the control unit predicts the trajectory of the terminal using a learned learning model based on information related to the terminal or other terminals, and the transceiver unit transmits the trajectory of the terminal to the other base station.

[0011] One aspect of the disclosure is a base station (gNB100A) comprising: a transceiver unit (transceiver unit 110) that transmits a message to another base station (gNB100B) regarding the addition or change of a secondary node to which a terminal (UE200) connects; and a control unit (control unit 150) that includes in the message a security key required for the terminal to connect to the other base station, wherein the control unit includes in the message a counter value used by the terminal to derive the security key.

[0012] One aspect of the disclosure is a wireless communication method comprising a transmission and reception step of transmitting and receiving wireless signals between a terminal (UE200) simultaneously connected to a base station (gNB100A) and another base station (gNB100B), and a control step of requesting the other base station to change the base station to which the terminal is connected, wherein the control step requests the other base station to provide the number of counter values ​​for deriving the security key required each time the terminal changes its connection with the base station.

[0013] FIG. 1 is a diagram showing an overall schematic configuration of a wireless communication system. FIG. 2 is a diagram showing a frequency range used in the wireless communication system. FIG. 3 is a diagram showing an example configuration of a wireless frame, subframe, slot, and symbol used in the wireless communication system. FIG. 4 is a functional block diagram of a base station. FIG. 5 is a functional block diagram of a terminal. FIG. 6 is a diagram showing the relationship between an SN Counter (Sk counter) set in an SN and a change of SN. FIG. 7 is a sequence diagram showing an example of CPC. FIG. 8 is a sequence diagram showing an example of CPC. FIG. 9 is a sequence diagram showing an example of CPC. FIG. 10 is a sequence diagram showing transmission of an SN Addition / Modification Request message. FIG. 11 is a diagram showing an example of IEs included in an SN Modification Required message. FIG. 12 is a diagram showing an example of IEs included in an SN Addition Request message. FIG. 13 is a diagram showing an example of the hardware configuration of a base station and a terminal. FIG. 14 is a diagram showing an example of the configuration of a vehicle.

[0014] Hereinafter, embodiments will be described with reference to the drawings. Note that the same or similar reference numerals are used to designate the same functions or configurations, and descriptions thereof will be omitted as appropriate.

[0015] (1) Overall Schematic Configuration of Wireless Communication System The wireless communication system 10 shown in Fig. 1 is a wireless communication system conforming to a method called 5G. Alternatively, the wireless communication system 10 may be a wireless communication system conforming to a method called Beyond 5G, 5G Evolution, or 6G.

[0016] The wireless communication system 10 can support Massive Multiple-Input Multiple-Output (Massive MIMO), which generates more directional beams by controlling wireless signals transmitted from multiple antenna elements, Carrier Aggregation (CA), which uses multiple component carriers (CCs) as a bundle, and Dual Connectivity (DC), which enables simultaneous communication with two base stations.

[0017] As shown in FIG. 1 , the wireless communication system 10 includes a base station (gNodeB, gNB) 100 connected to a Next Generation-Radio Access Network (NG-RAN) 20, and a terminal (User Equipment, UE) 200 that performs wireless communication with the gNB 100. The NG-RAN 20 is connected to a core network (CN) (not shown). The CN is configured by a network function (NF) such as an access and mobility management function (AMF). The NG-RAN 20 and the CN may be simply referred to as a "network," and may or may not be considered to be included in the wireless communication system 10. Note that the specific configuration of the wireless communication system 10, for example, the number of gNBs 100 and UEs 200, is not limited to the example shown in FIG. 1 .

[0018] In the embodiment, the gNB100 includes a gNB100A constituting an MN and a gNB100B constituting an SN. The UE200 can simultaneously connect to the gNB100A and the gNB100B and execute DC. Furthermore, when performing CPC to change the PSCell formed by the gNB100B, the UE200 can retain the PSCell configuration information without repeatedly acquiring and discarding the PSCell configuration information. This type of mobility may be referred to as subsequent mobility. Subsequent mobility may be interpreted as a concept that includes not only CPC but also Conditional PSCell Addition (CPA) and inter-SN PSCell Lower layer Triggered Mobility (LTM). Therefore, CPC in the following description and drawings may be interpreted as other aspects of subsequent mobility, such as CPA, CPA / CPC (CPAC), and inter-SN PSCell LTM.

[0019] The wireless communication system 10 may also support multiple frequency ranges (FR). That is, as shown in Fig. 2, the wireless communication system 10 may support the following FRs: FR1: 410 MHz to 7.125 GHz FR2-1: 24.25 GHz to 52.6 GHz FR2-2: Over 52.6 GHz to 71 GHz

[0020] In FR1, a subcarrier spacing (SCS) of 15, 30, or 60 kHz and a bandwidth (BW) of 5 to 100 MHz may be used, while in FR2-1, an SCS of 60 or 120 kHz (including 240 kHz) and a BW of 50 to 400 MHz may be used.

[0021] In FR2-2, to avoid an increase in phase noise, Cyclic Prefix-Orthogonal Frequency Division Multiplexing (CP-OFDM) or Discrete Fourier Transform-Spread-Orthogonal Frequency Division Multiplexing (DFT-S-OFDM) with a larger SCS may be applied.

[0022] 3, one slot in the wireless communication system 10 is composed of 14 symbols. If this configuration is maintained, the larger (wider) the SCS, the shorter the symbol period (and slot period). Note that the SCS is not limited to the frequencies shown in FIG. 3 and may be, for example, 480 kHz, 960 kHz, or other frequencies.

[0023] Furthermore, the number of symbols constituting one slot does not necessarily have to be 14, but may be, for example, 28 or 56. Furthermore, the number of slots per subframe may differ depending on the SCS.

[0024] (2) Functional block configuration of wireless communication system (2.1) Functional block configuration of base station As shown in Figure 4, the gNB 100 includes a transceiver unit 110, a generation unit 120, a prediction unit 130, an HO unit 140, and a control unit 150.

[0025] The transmission / reception unit 110 transmits and receives radio signals to and from the UE 200. The transmission / reception unit 110 may include a transmission unit that transmits radio signals to the UE 200 and a reception unit that receives radio signals from the UE 200.

[0026] The transceiver 110 can support DC executed by the UE200. That is, the transceiver 110 of the gNB100 transmits and receives radio signals to and from UE200 simultaneously connected to another gNB100. Note that the gNB100 may be a gNB100A constituting an MN, or a gNB100B constituting an SN. Similarly, the other gNB100 may be a gNB100A constituting an MN, or a gNB100B constituting an SN.

[0027] The transceiver 110 transmits the message generated by the generator 120 to the other gNB100 or the UE200. The transceiver 110 also receives, from the other gNB100 or the UE200, a message generated by the other gNB100 or a measurement report generated by the UE200.

[0028] The generator 120 generates various messages.

[0029] The generation unit 120 included in the gNB100B constituting the SN generates a message related to a change of the SN (gNB100B) to which the UE 200 connects. Specifically, the generation unit 120 generates messages such as Xn messages such as an SN Modification / Change Required message, and AIML Information-based messages (see FIG. 9 ) that are based on the use of Artificial Intelligence Machine Learning (AIML).

[0030] The generation unit 120 included in the gNB 100A constituting the MN generates a message related to the addition or modification of the SN (gNB 100B) to which the UE 200 connects. Specifically, the generation unit 120 generates messages such as an Xn message such as an SN Addition / Modification Request message, an RRC Reconfiguration message, and the like.

[0031] The prediction unit 130 performs various predictions using AIML, specifically, a learning model. The learning model is learned, for example, from a measurement report transmitted from the UE 200. That is, the prediction unit 130 performs various predictions using a learning model that has been learned from the measurement report of the UE 200. Note that the form of the learning model is not limited to this, but a description thereof will be omitted here and will be described in detail in the section on operation examples.

[0032] The various predictions include, for example, the number of counter values ​​for deriving a security key by the UE 200, the number of times the UE 200 changes its connection with the gNB 100, and the trajectory of the UE 200's movement (hereinafter simply referred to as the trajectory of the UE 200). Hereinafter, for convenience of explanation, these predicted parameters (the number of counter values, the number of connection changes, and the movement trajectory) may also be referred to as predicted values. Note that the prediction unit 130 in the embodiment is assumed to be included in the gNB 100B constituting the SN (see Figures 8 and 9), but may also be included in the gNB 100A constituting the MN.

[0033] The HO unit 140 executes handover (HO) of the UE 200. The HO in the embodiment is understood to include subsequent mobility such as the above-mentioned CPC, CPA, and inter-SN PSCell LTM.

[0034] The control unit 150 controls the gNB 100. The control unit 150 controls, for example, the transmission and reception of radio signals by the transceiver unit 110, the generation of various messages by the generation unit 120, various predictions by the prediction unit 130, and the HO by the HO unit 140.

[0035] The control unit 150 included in the gNB 100B constituting the SN checks whether the security key used by the UE 200 when performing CPC is the same as or corresponds to the security key previously acquired from the gNB 100A constituting the MN. Specifically, the control unit 150 checks whether the security key previously acquired from the gNB 100A and the security key transmitted from the UE 200 are the same as or correspond to each other.

[0036] This allows the gNB100B to securely connect to the UE200. In the embodiment, the security key is required every time the UE200 changes its connection with the gNB100B. Note that "changing the connection" may be interpreted as including not only an SN Change that changes the gNB100B to be connected, but also an SN Modification that changes the settings related to the gNB100B to be connected.

[0037] The control unit 150 included in the gNB 100B constituting the SN can request the gNB 100A constituting the MN for the number of counter values ​​for deriving a security key by the UE 200. Specifically, the control unit 150 can include the number of requested counter values ​​or the above-mentioned predicted value in various messages generated by the generation unit 120 (see FIGS. 7 and 8).

[0038] The control unit 150 included in the gNB 100A constituting the MN can determine the number of counter values ​​from which the UE 200 derives a security key. Here, "determining the number of counter values" may mean determining the number of counter values ​​based on a request from the gNB 100B constituting the SN, or may mean deriving the number of counter values ​​based on a predicted value transmitted from the gNB 100B constituting the SN. For example, the control unit 150 may determine the number of counter values ​​transmitted from the gNB 100B constituting the SN as the number of counter values ​​to be set in the gNB 100B and the UE 200. Furthermore, the control unit 150 may derive the number of counter values ​​to be set in the gNB 100B and the UE 200 from the predicted value transmitted from the gNB 100B constituting the SN. Here, "derive" may be interpreted as "determine."

[0039] The number of counter values ​​is set from the gNB 100A constituting the MN to the gNB 100B constituting the SN and the UE 200. Specifically, the control unit 150 included in the gNB 100A constituting the MN can include the determined number of counter values ​​in various messages generated by the generation unit 120 (see Figures 7 to 10). Furthermore, the security key corresponding to the counter value is set in the gNB 100B constituting the SN. That is, the control unit 150 included in the gNB 100A constituting the MN can include not only the security key but also the counter value corresponding to the security key in various messages generated by the generation unit 120 (see Figure 10). In this case, the number of security keys and corresponding counter values ​​is not limited to one, and there may be multiple security keys and corresponding counter values.

[0040] (2.2) Functional Block Configuration of Terminal As shown in FIG. 5, the UE 200 includes a transceiver 210, a generator 220, and a controller 230.

[0041] The transceiver 210 transmits and receives radio signals to and from the gNB 100. The transceiver 210 may include a transmitter that transmits radio signals to the gNB 100 and a receiver that receives radio signals from the gNB 100.

[0042] The transceiver 210 can execute DC by simultaneously connecting to the gNB100A constituting the MN and the gNB100B constituting the SN. In the embodiment, the transceiver 210 transmits a measurement report generated by the generator 120 to the gNB100B. The transceiver 210 also receives a message generated by the gNB100A from the gNB100A. The transceiver 210 may transmit a measurement report to the gNB100A, or may receive a message generated by the gNB100B from the gNB100B.

[0043] The generation unit 220 generates a measurement report. In an embodiment, the measurement report may include not only the reception quality of the cell formed by the gNB100, but also the trajectory of the UE200, the number of times a security key is derived in a predetermined period (the number of times a counter value is used), the number of times a connection with the gNB100 is changed in a predetermined period, and the like.

[0044] The control unit 230 controls the UE 200. The control unit 230 controls, for example, the transmission and reception of radio signals by the transceiver unit 210 and the generation of measurement reports by the generation unit 220.

[0045] The control unit 230 derives a necessary security key from a counter value previously acquired from the gNB 100A constituting the MN each time the connection with the gNB 100B constituting the SN is changed. The control unit 230 derives one security key from one counter value. Note that the counter value is used only once, and the same counter value is not reused to derive a security key. However, if the counter value is reacquired from the gNB 100A constituting the MN due to depletion of the counter value, the same counter value can be reused.

[0046] (3) Counter Value and CPC The counter value and CPC in the embodiment will be described with reference to FIG. 6. Note that the counter value in FIG. 6 is referred to as Sk counter, which has the same meaning as SN Counter. Also, for convenience of explanation, in FIG. 6, the Sk counter assigned to each SN (SN1, SN2, SN3) is not a counter value, but a security key derived from the counter value. Note that the "security key derived from the counter value" may be interpreted as the security key corresponding to the counter value. Similarly, the "counter value from which a security key is derived" may be interpreted as the counter value corresponding to the security key.

[0047] Assuming that UE 200 performs CPC, as shown in the upper part of Fig. 6, three security keys corresponding to Sk counter = 1, 2, 3 are set in SN1, three security keys corresponding to Sk counter = 5, 6, 7 are set in SN2, and three security keys corresponding to Sk counter = 9, 10, 11 are set in SN3. Similarly, nine counter values ​​of Sk counter = 1, 2, 3, 5, 6, 7, 9, 10, 11 are set in UE 200.

[0048] As shown in the lower part of Fig. 6, a case will be described in which UE200 performs CPC in the order of SN1, SN2, SN3, SN2, SN3, SN2, and SN1. First, in order to connect to SN1 in CPC, UE200 derives a security key from a counter value (here, Sk counter = 1) for deriving one of the security keys set in SN1, and securely connects to SN1. Next, UE200 connects to SN2 using Sk counter = 5, and further connects to SN3 using Sk counter = 9.

[0049] Here, when UE200 performs CPC for SN2 again, it uses an unused counter value (here, Sk counter=6) which is a counter value corresponding to the security key set in SN2. Similarly, when UE200 performs CPC for SN3 again, it uses an unused counter value (here, Sk counter=10), and when UE200 performs CPC for SN2 again, it uses an unused counter value (here, Sk counter=7). As a result, the security key set in SN2 and the corresponding counter value are exhausted, so SN2 and UE200 need to reacquire the security key and the corresponding counter value from the MN, respectively. UE200 can perform CPC until the counter value is exhausted. For example, since the security key set in SN1 has not been exhausted, UE200 can reconnect to SN1 by using an unused counter value (here, Sk counter=2).

[0050] Although the example in which the counter values ​​are used in ascending order has been described with reference to FIG. 6, the counter values ​​may be used in descending order, or in another predetermined order.

[0051] (4) Operation of wireless communication system (4.1) Issues In subsequent mobility, where a UE executing DC does not perform RRC Reconfiguration every time it changes its connection with an SN, the number of SN Counters set in the UE to securely connect to the SN may be determined, for example, by the MN. However, in such a case, the following problems may occur.

[0052] That is, when a UE connects to a PSCell, the SN has more detailed information than the MN, and the number of SN Counters determined by the MN may not match the actual mobility situation. Also, the SN cannot grasp which SN Counter the UE is using to derive the security key, and there is a risk that the UE and the SN may not have a common understanding of the security key.

[0053] (4.2) Operational Examples (4.2.1) Operational Example 1 An operational example in which an SN (gNB100B) proposes the number of SN Counters to an MN (gNB100A) will be described with reference to Fig. 7. Note that the SN in Fig. 7 is assumed to be the Source SN, but may also be the Target SN.

[0054] When UE200 performs CPC, gNB100B transmits SN Modification / Change Required to gNB100A (step S11). At this time, gNB100B includes the number of SN Counters requested (e.g., 3) in the SN Modification / Change Required.

[0055] The gNB100A determines the number of SN Counters based on this number of SN Counters (step S12). Note that "determining the number of SN Counters based on the number of SN Counters" may mean determining the number of SN Counters as requested by the gNB100B, or may mean determining the number of SN Counters by partially accepting the request from the gNB100B. For example, the number of SN Counters may be determined by adding or subtracting a predetermined number (e.g., 1) from the number of SN Counters requested by the gNB100B.

[0056] The gNB 100A sets SN Counters corresponding to the determined number of SN Counters in the UE 200 (step S13). In the example of Fig. 6, the determined number of SN Counters is three and there are three candidate SNs, so a total of nine SN Counters (Sk counters) = 1, 2, 3, 5, 6, 7, 9, 10, and 11 are set.

[0057] (4.2.2) Operation Example 2 With reference to Fig. 8, an operation example will be described in which an SN (gNB100B) predicts the number of SN Counters required or the number of times to change the connection with the gNB100 and proposes this predicted value to an MN (gNB100A). Note that the SN in Fig. 8 is assumed to be a Source SN, but may also be a Target SN.

[0058] In this operation example, a measurement report is transmitted in advance from the UE 200 to the gNB 100B (step S21), and the measurement report is trained in a learning model in the gNB 100B (step S22). However, the mode of the learning model is not limited to this. For example, the learning model may be trained based on information from another UE 200. Furthermore, a learning model trained in another gNB 100 based on information from another UE 200 may be used as the learning model used in the gNB 100B. In this case, steps S21 and S22 can be omitted. In other words, the learning model in the gNB 100B may be a learning model trained based on information related to the UE 200 or another UE 200.

[0059] When UE200 performs CPC, UE200 transmits a measurement report to gNB100B (step S23), and gNB100B performs prediction using the learning model (step S24). That is, gNB100B derives a predicted value for the number of SN Counters or the number of times the connection with gNB100 will be changed.

[0060] Next, gNB100B transmits SN Modification / Change Required to gNB100A (step S25). At this time, gNB100B includes the above-mentioned predicted value in the SN Modification / Change Required.

[0061] The gNB100A determines the number of SN counters based on this predicted value (step S26). Note that "determining the number of SN counters based on the predicted value" may mean determining the number of SN counters according to the predicted value of the gNB100B, or may mean determining the number of SN counters by partially accepting the predicted value of the gNB100B. For example, the number of SN counters may be determined by adding or subtracting a predetermined number (e.g., 1) from the predicted value of the gNB100B.

[0062] Step S27 is the same as step S13 described above, and therefore a description thereof will be omitted.

[0063] (4.2.3) Operation Example 3 With reference to Fig. 9, an operation example will be described in which the trajectory of UE200 is predicted from the SN (gNB100B) to the MN (gNB100A), and the MN derives the number of SN Counters based on this predicted value. Note that the SN in Fig. 9 is assumed to be the Source SN, but may also be the Target SN.

[0064] Steps S31 to S33 are the same as steps S21 to S23 described above, and therefore a description thereof will be omitted.

[0065] Then, the gNB100B performs prediction using the learning model (step S34). However, unlike the operation example 2, the gNB100B derives a predicted value of the trajectory of the UE200.

[0066] Next, the gNB100B transmits an AIML Information Response or Update to the gNB100A (step S35). At this time, the gNB100B includes the above-mentioned predicted value in the AIML Information Response or Update.

[0067] The gNB100A derives the number of SN Counters based on this predicted value (step S36). Thereafter, the gNB100A receives an SN Modification / Change Required from the gNB100B (step S37) and proceeds to step S38. Note that step S37 is not necessarily required, and the process may proceed to step S38 in response to steps S35 and S36.

[0068] Steps S38 and S39 are the same as steps S26 and S27 described above, and therefore their explanation will be omitted.

[0069] (4.2.4) Operation Example 4 An operation example in which an MN (gNB100A) transmits an SN Counter corresponding to a security key set in the SN to an SN (gNB100B) will be described with reference to Fig. 10. Note that the SN in Fig. 10 is assumed to be a Source SN, but may also be a Target SN.

[0070] As shown in Figure 10, gNB100A sends an SN Addition / Modification Request to gNB100B. In this operation example, the SN Addition / Modification Request includes multiple security keys configured in gNB100B. In the SN Addition / Modification Request, gNB100A can send SN Counters corresponding to each of the multiple security keys (or the correspondence between which SN Counters correspond to which security keys). This allows gNB100B to understand not only the multiple security keys configured in itself, but also which SN Counters each security key corresponds to.

[0071] (4.2.5) Information Element An example of an information element (IE) indicating the number of SN Counters in the above-described operation example will be described with reference to FIGS.

[0072] First, examples of IEs in operation example 1 will be described with reference to Fig. 11. An IE may be included (or independent) in any of the following ways, but the IEs shown in Fig. 11 are examples of IEs included in SN Modification Required. When included in SN Modification Required: in CPAC Information Required / in another existing list / in another new list / independent IE When included in SN Change Required: in Conditional PSCell Change Information Required / in another existing list / in another new list / independent IE

[0073] Also, maxofSNCounters shown in FIG. 11 may be newly defined as a constant representing the maximum number of SN Counters that can be set simultaneously.

[0074] Next, examples of IEs in Operation Example 4 will be described with reference to Fig. 12. An IE may be included (or independent) in any of the following ways, but the IEs shown in Fig. 12 are examples of IEs included in an SN Addition Request. When included in an SN Addition Request: in a Conditional PSCell Addition Information Request / in another existing list / in another new list / independent IE When included in an SN Modification Request: in a Conditional PSCell Change Information Update > Multiple Target S-NG-RAN Node List > Multipler Target S-NG-RAN Node Item / in another existing list / in another new list / independent IE

[0075] Also, the * mark in the IE shown in FIG. 12 may be interpreted as SN Counter defined in TS 33.501.

[0076] (4.3) Effect By incorporating a proposal from the SN regarding the number of SN Counters to be set in the UE for subsequent mobility, it is possible to reduce signaling overhead and UE resource consumption. In addition, by associating the SN Counters corresponding to the security keys with the security keys set in the SN and transmitting them to the SN, it is possible to have a common understanding of the security keys between the UE and the SN, thereby avoiding a situation where the security keys do not match between the two.

[0077] (5) Other Embodiments The contents of the present invention have been described above in accordance with the embodiments, but it will be obvious to those skilled in the art that the present invention is not limited to these descriptions and that various modifications and improvements are possible.

[0078] In the above-disclosed operation examples 1 and 2, gNB100A determining the number of SN Counters according to the request or predicted value of gNB100B may be interpreted as, for example, the following (using the SN Modification Required message as an example):

[0079] If the CPAP Information Required IE of the S-Node Modification Required message includes the number or predicted value of the SN Counter (or its IE), the M-NG-RAN node (gNB100A) uses this number or predicted value of the SN Counter as the number of sk counters to be configured in the UE200 in the configuration update of the list of PSCells prepared in the target SN (if such operation is supported).

[0080] In the above-disclosed operation examples 1 and 2, gNB100A partially accepts the request or predicted value of gNB100B to determine the number of SN Counters, which may be interpreted as, for example, the following (using the SN Modification Required message as an example):

[0081] If the CPAP Information Required IE in the S-Node Modification Required message includes the number or predicted value of the SN Counter (or the IE), the M-NG-RAN node (gNB100A) considers this request to provide the number of sk counters to be configured in the UE200 in a configuration update of the list of PSCells prepared in the target SN (if such behavior is supported).

[0082] In the above disclosure, the trajectory (movement range) of a UE in subsequent mobility is not limited to adjacent gNBs 100, but may span multiple (non-adjacent) gNBs 100. Therefore, the predicted value of the trajectory of UE 200 may also correspond to this. Furthermore, the predicted value of the trajectory of UE 200 may be based on the cell ID of a cell in which UE 200 is predicted to reside and the time during which UE 200 is predicted to reside in this cell. Then, the number of SN Counters may be determined based on this predicted value (the predicted value of the residency time in the cell in which UE 200 is predicted to reside).

[0083] In the above disclosure, the gNB 100B constituting the SN proposes to the gNB 100A constituting the MN the number of counter values ​​to be set in the gNB 100B and the UE 200. However, the counter values ​​themselves may be proposed in addition to the number of counter values. For example, after the security keys corresponding to SN counters = 5, 6, and 7 are exhausted, SN2 in FIG. 6 may propose the same SN counters = 5, 6, and 7 as counter values ​​corresponding to a newly acquired security key, or may propose different SN counters = 13, 14, and 15. In this case, instead of the counter values, a list containing multiple counter values ​​(e.g., a Candidate SN Counters List) may be proposed. Furthermore, in this case, to avoid duplication of counter values ​​with other SNs, counter values ​​for all SNs may be proposed, not just the counter value for the SN whose security keys have been exhausted.

[0084] In the above disclosure, when the security key of any SN or the corresponding SN Counter is exhausted (for example, SN2 in FIG. 6 ), SN2 (gNB100B) may acquire the security key (and the corresponding SN Counter described in Operation Example 4) from the MN (gNB100A). Accordingly, UE200 may acquire the SN Counter corresponding to the security key from gNB100A. The timing for acquiring the security key and SN Counter may be when the security key set for any SN is exhausted, or when the SN Counter set for UE200 (i.e., the SN Counter corresponding to the security keys of all SNs to which UE200 can securely connect) is exhausted. Note that "(re)acquire" may be interpreted as "update."

[0085] The above-described operation examples may be combined and applied in a composite manner, as long as no contradiction occurs.

[0086] In the above disclosure, configure, activate, update, indicate, enable, specify, and select may be interchangeable. Similarly, link, associate, correspond, and map may be interchangeable, and allocate, assign, monitor, and map may be interchangeable.

[0087] Furthermore, specific, dedicated, UE-specific, and UE-dedicated may be interchangeable. Similarly, common, shared, group-common, UE-common, and UE-shared may be interchangeable.

[0088] The block diagrams (FIGS. 4 and 5) used to explain the above-described embodiments show functional blocks. These functional blocks (components) are realized by any combination of hardware and / or software. Furthermore, the method for realizing each functional block is not particularly limited. That is, each functional block may be realized using a single device that is physically or logically coupled, or may be realized using two or more physically or logically separated devices that are directly or indirectly connected (e.g., wired, wireless, etc.) and these multiple devices. The functional block may be realized by combining software with the single device or multiple devices.

[0089] Functions include, but are not limited to, judgment, determination, judgment, calculation, computation, processing, derivation, investigation, search, confirmation, reception, transmission, output, access, resolution, selection, election, establishment, comparison, assumption, expectation, regard, broadcasting, notifying, communicating, forwarding, configuring, reconfiguring, allocating, mapping, and assignment. For example, a functional block (component) that performs transmission is called a transmitting unit or transmitter. As mentioned above, there are no particular limitations on how each is implemented.

[0090] Furthermore, the above-described gNB 100 and UE 200 (the devices) may function as a computer that performs processing of the wireless communication method of the present disclosure. Figure 13 is a diagram showing an example of the hardware configuration of the devices. As shown in Figure 13, the devices may be configured as a computer including a processor 1001, a memory 1002, a storage 1003, a communication device 1004, an input device 1005, an output device 1006, a bus 1007, etc.

[0091] In the following description, the term "apparatus" can be interpreted as a circuit, a device, a unit, etc. The hardware configuration of the apparatus may be configured to include one or more of the apparatuses shown in the drawings, or may be configured to exclude some of the apparatuses.

[0092] Each functional block of the device (FIGS. 4 and 5) is realized by any hardware element of the computer device or a combination of the hardware elements.

[0093] In addition, each function of the device is realized by loading specified software (programs) onto hardware such as processor 1001 and memory 1002, causing processor 1001 to perform calculations, control communication via communication device 1004, and control at least one of reading and writing data in memory 1002 and storage 1003.

[0094] The processor 1001 controls the entire computer by running, for example, an operating system, and may be configured as a central processing unit (CPU) including an interface with peripheral devices, a control unit, an arithmetic unit, and registers.

[0095] The processor 1001 also reads programs (program codes), software modules, data, etc. from at least one of the storage 1003 and the communication device 1004 into the memory 1002 and executes various processes in accordance with these. The programs used are those that cause a computer to execute at least some of the operations described in the above-described embodiments. Furthermore, the various processes described above may be executed by a single processor 1001, or may be executed simultaneously or sequentially by two or more processors 1001. The processor 1001 may be implemented by one or more chips. The programs may be transmitted from a network via a telecommunications line.

[0096] The memory 1002 is a computer-readable recording medium and may be configured by at least one of, for example, a read-only memory (ROM), an erasable programmable ROM (EPROM), an electrically erasable programmable ROM (EEPROM), a random access memory (RAM), etc. The memory 1002 may also be called a register, a cache, a main memory (primary storage device), etc. The memory 1002 may store a program (program code), a software module, etc., capable of executing a method according to an embodiment of the present disclosure.

[0097] Storage 1003 is a computer-readable recording medium, and may be, for example, at least one of an optical disk such as a Compact Disc ROM (CD-ROM), a hard disk drive, a flexible disk, a magneto-optical disk (e.g., a compact disk, a digital versatile disk, a Blu-ray disc), a smart card, a flash memory (e.g., a card, a stick, a key drive), a floppy disk, a magnetic strip, etc. Storage 1003 may also be referred to as an auxiliary storage device. The above-mentioned recording medium may be, for example, a database, a server, or other suitable medium including at least one of memory 1002 and storage 1003.

[0098] The communication device 1004 is hardware (transmission / reception device) for communicating between computers via at least one of a wired network and a wireless network, and is also called, for example, a network device, a network controller, a network card, or a communication module.

[0099] The communication device 1004 may be configured to include a high-frequency switch, a duplexer, a filter, a frequency synthesizer, etc. to realize, for example, at least one of Frequency Division Duplex (FDD) and Time Division Duplex (TDD).

[0100] The input device 1005 is an input device (e.g., a keyboard, a mouse, a microphone, a switch, a button, a sensor, etc.) that receives input from the outside. The output device 1006 is an output device (e.g., a display, a speaker, an LED lamp, etc.) that outputs to the outside. Note that the input device 1005 and the output device 1006 may be integrated into one device (e.g., a touch panel).

[0101] Furthermore, each device such as the processor 1001 and the memory 1002 is connected to a bus 1007 for communicating information. The bus 1007 may be configured using a single bus, or may be configured using different buses between each device.

[0102] Furthermore, the device may be configured to include hardware such as a microprocessor, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a programmable logic device (PLD), or a field programmable gate array (FPGA), and some or all of the functional blocks may be realized by the hardware. For example, the processor 1001 may be implemented using at least one of these pieces of hardware.

[0103] Furthermore, the notification of information is not limited to the aspects / embodiments described in the present disclosure, and may be performed using other methods. For example, the notification of information may be performed by physical layer signaling (e.g., Downlink Control Information (DCI), Uplink Control Information (UCI)), higher layer signaling (e.g., RRC signaling, Medium Access Control (MAC) signaling), broadcast information (Master Information Block (MIB), System Information Block (SIB)), other signals, or a combination thereof. Furthermore, the RRC signaling may be referred to as an RRC message, and may be, for example, an RRC Connection Setup message, an RRC Connection Reconfiguration message, or the like.

[0104] Each aspect / embodiment described in the present disclosure may be applied to at least one of a system using Long Term Evolution (LTE), LTE-Advanced (LTE-A), SUPER 3G, IMT-Advanced, a 4th generation mobile communication system (4G), a 5th generation mobile communication system (5G), Future Radio Access (FRA), New Radio (NR), W-CDMA (registered trademark), GSM (registered trademark), CDMA2000, Ultra Mobile Broadband (UMB), IEEE 802.11 (Wi-Fi (registered trademark)), IEEE 802.16 (WiMAX (registered trademark)), IEEE 802.20, Ultra-WideBand (UWB), Bluetooth (registered trademark), or other suitable system, and a next-generation system enhanced based on these. Furthermore, a combination of multiple systems (e.g., a combination of at least one of LTE and LTE-A and 5G) may also be applied.

[0105] The order of the procedures, sequences, flowcharts, etc. of each aspect / embodiment described in this disclosure may be changed unless it is consistent. For example, the methods described in this disclosure present elements of various steps using an example order, and are not limited to the particular order presented.

[0106] In the present disclosure, a specific operation described as being performed by a base station may be performed by its upper node in some cases. In a network consisting of one or more network nodes having a base station, it is clear that various operations performed for communication with a terminal may be performed by at least one of the base station and another network node other than the base station (for example, an MME or an S-GW, etc., but are not limited to these). Although the above example illustrates a case where there is one other network node other than the base station, a combination of multiple other network nodes (for example, an MME and an S-GW) may also be used.

[0107] Information, signals (information, etc.) may be output from a higher layer (or a lower layer) to a lower layer (or a higher layer), or may be input / output via multiple network nodes.

[0108] The input and output information may be stored in a specific location (for example, a memory) or may be managed using a management table. The input and output information may be overwritten, updated, or added. The output information may be deleted. The input information may be transmitted to another device.

[0109] The determination may be made based on a value represented by one bit (0 or 1), a Boolean value (true or false), or a numerical comparison (e.g., comparison with a predetermined value).

[0110] The aspects / embodiments described in this disclosure may be used alone, in combination, or switched depending on the implementation. Notification of predetermined information (e.g., notification that "X is true") is not limited to explicit notification, but may be implicit (e.g., not notifying the predetermined information).

[0111] Software shall be construed broadly to mean instructions, instruction sets, code, code segments, program code, programs, subprograms, software modules, applications, software applications, software packages, routines, subroutines, objects, executable files, threads of execution, procedures, functions, etc., whether referred to as software, firmware, middleware, microcode, hardware description language, or otherwise.

[0112] Software, instructions, information, etc. may also be transmitted or received over a transmission medium. For example, if software is transmitted from a website, server, or other remote source using wired technologies (such as coaxial cable, fiber optic cable, twisted pair, Digital Subscriber Line (DSL)), and / or wireless technologies (such as infrared, microwave), then these wired and / or wireless technologies are included within the definition of transmission media.

[0113] The information, signals, etc. described in this disclosure may be represented using any of a variety of different technologies. For example, data, instructions, commands, information, signals, bits, symbols, chips, etc. that may be referred to throughout the above description may be represented by voltages, currents, electromagnetic waves, magnetic fields or magnetic particles, optical fields or photons, or any combination thereof.

[0114] Note that terms described in this disclosure and terms necessary for understanding this disclosure may be replaced with terms having the same or similar meanings. For example, at least one of a channel and a symbol may be a signal (signaling). Furthermore, a signal may be a message. Furthermore, a component carrier (CC) may be called a carrier frequency, a cell, a frequency carrier, etc.

[0115] As used in this disclosure, the terms "system" and "network" are used interchangeably.

[0116] Furthermore, the information, parameters, etc. described in the present disclosure may be expressed using absolute values, may be expressed using relative values ​​from a predetermined value, or may be expressed using other corresponding information. For example, a radio resource may be indicated by an index.

[0117] The names used for the above-described parameters are not intended to be limiting in any way. Furthermore, the mathematical expressions using these parameters may differ from those explicitly disclosed in this disclosure. The various channels (e.g., PUCCH, PDCCH, etc.) and information elements may be identified by any suitable names, and therefore the various names assigned to these various channels and information elements are not intended to be limiting in any way.

[0118] In this disclosure, terms such as "base station (BS)," "radio base station," "fixed station," "NodeB," "eNodeB (eNB)," "gNodeB (gNB)," "access point," "transmission point," "reception point," "transmission / reception point," "cell," "sector," "cell group," "carrier," and "component carrier" may be used interchangeably. Base stations may also be referred to by terms such as macrocell, small cell, femtocell, and picocell.

[0119] A base station can accommodate one or more (e.g., three) cells (also called sectors). When a base station accommodates multiple cells, the overall coverage area of ​​the base station can be divided into multiple smaller areas, and each smaller area can be provided with communication services by a base station subsystem (e.g., a small indoor base station (Remote Radio Head: RRH)).

[0120] The terms "cell" or "sector" refer to part or all of the coverage area of ​​a base station and / or base station subsystem that provides communication services within that coverage area.

[0121] In this disclosure, the terms "Mobile Station (MS)," "user terminal," "User Equipment (UE)," "terminal," etc. may be used interchangeably.

[0122] A mobile station may also be referred to by those skilled in the art as a subscriber station, mobile unit, subscriber unit, wireless unit, remote unit, mobile device, wireless device, wireless communication device, remote device, mobile subscriber station, access terminal, mobile terminal, wireless terminal, remote terminal, handset, user agent, mobile client, client, or some other suitable terminology.

[0123] At least one of the base station and the mobile station may be referred to as a transmitting device, a receiving device, a communication device, etc. At least one of the base station and the mobile station may be a device mounted on a mobile object, the mobile object itself, etc. The mobile object may be a vehicle (e.g., a car, an airplane, etc.), an unmanned mobile object (e.g., a drone, an autonomous vehicle, etc.), or a robot (manned or unmanned). At least one of the base station and the mobile station may also include devices that do not necessarily move during communication operations. For example, at least one of the base station and the mobile station may be an Internet of Things (IoT) device such as a sensor.

[0124] Furthermore, a base station in the present disclosure may be read as a mobile station (user terminal, the same applies hereinafter). For example, the aspects / embodiments of the present disclosure may be applied to a configuration in which communication between a base station and a mobile station is replaced with communication between multiple mobile stations (which may be called, for example, Device-to-Device (D2D) or Vehicle-to-Everything (V2X)). In this case, the mobile station may be configured to have the functions of a base station. Furthermore, terms such as "uplink" and "downlink" may be read as terms corresponding to terminal-to-terminal communication (for example, "side"). For example, terms such as an uplink channel and a downlink channel may be read as a side channel.

[0125] Similarly, a mobile station in the present disclosure may be interpreted as a base station, in which case the base station may have the functions of a mobile station.

[0126] A radio frame may be made up of one or more frames in the time domain, each of which may be called a subframe.

[0127] A subframe may further be composed of one or more slots in the time domain, and may have a fixed time length (e.g., 1 ms) that is independent of numerology.

[0128] Numerology may be communication parameters that apply to the transmission and / or reception of a signal or channel, such as subcarrier spacing (SCS), bandwidth, symbol length, cyclic prefix length, transmission time interval (TTI), number of symbols per TTI, radio frame structure, specific filtering operations performed by the transceiver in the frequency domain, and specific windowing operations performed by the transceiver in the time domain.

[0129] A slot may consist of one or more symbols in the time domain (such as Orthogonal Frequency Division Multiplexing (OFDM) symbols, Single Carrier Frequency Division Multiple Access (SC-FDMA) symbols, etc.) A slot may be a time unit based on numerology.

[0130] A slot may include multiple minislots. Each minislot may consist of one or multiple symbols in the time domain. A minislot may also be called a subslot. A minislot may consist of fewer symbols than a slot. A PDSCH (or PUSCH) transmitted in a time unit larger than a minislot may be called PDSCH (or PUSCH) mapping type A. A PDSCH (or PUSCH) transmitted using a minislot may be called PDSCH (or PUSCH) mapping type B.

[0131] The radio frame, subframe, slot, minislot, and symbol all represent time units for transmitting signals, and may be referred to by other names corresponding to the radio frame, subframe, slot, minislot, and symbol.

[0132] For example, one subframe may be referred to as a transmission time interval (TTI), multiple consecutive subframes may be referred to as a TTI, or one slot or one minislot may be referred to as a TTI. That is, at least one of the subframe and the TTI may be a subframe (1 ms) in existing LTE, a period shorter than 1 ms (e.g., 1-13 symbols), or a period longer than 1 ms. Note that the unit representing the TTI may be referred to as a slot, minislot, etc. instead of a subframe.

[0133] Here, TTI refers to, for example, the smallest time unit for scheduling in wireless communication. For example, in an LTE system, a base station schedules each user terminal to allocate radio resources (such as frequency bandwidth and transmission power that can be used by each user terminal) in TTI units. Note that the definition of TTI is not limited to this.

[0134] The TTI may be a transmission time unit for a channel-encoded data packet (transport block), a code block, a code word, etc., or may be a processing unit for scheduling, link adaptation, etc. When a TTI is given, the time interval (e.g., the number of symbols) to which a transport block, a code block, a code word, etc. is actually mapped may be shorter than the TTI.

[0135] In addition, when one slot or one minislot is called a TTI, one or more TTIs (i.e., one or more slots or one or more minislots) may be the minimum time unit for scheduling. Furthermore, the number of slots (minislots) constituting the minimum time unit for scheduling may be controlled.

[0136] A TTI having a time length of 1 ms may be called a regular TTI (TTI in LTE Rel. 8-12), normal TTI, long TTI, regular subframe, normal subframe, long subframe, slot, etc. A TTI shorter than a regular TTI may be called a shortened TTI, short TTI, partial or fractional TTI, shortened subframe, short subframe, minislot, subslot, slot, etc.

[0137] In addition, a long TTI (e.g., a normal TTI, a subframe, etc.) may be interpreted as a TTI having a time length of more than 1 ms, and a short TTI (e.g., a shortened TTI, etc.) may be interpreted as a TTI having a TTI length shorter than the TTI length of a long TTI and equal to or greater than 1 ms.

[0138] A resource block (RB) is a resource allocation unit in the time domain and the frequency domain, and may include one or more consecutive subcarriers in the frequency domain. The number of subcarriers included in an RB may be the same regardless of numerology, for example, 12. The number of subcarriers included in an RB may be determined based on numerology.

[0139] The time domain of an RB may include one or more symbols and may have a length of one slot, one minislot, one subframe, or one TTI. One TTI, one subframe, etc. may each be composed of one or more resource blocks.

[0140] Note that one or more RBs may also be called a physical resource block (PRB), a sub-carrier group (SCG), a resource element group (REG), a PRB pair, an RB pair, etc.

[0141] Furthermore, a resource block may be composed of one or more resource elements (REs). For example, one RE may be a radio resource region of one subcarrier and one symbol.

[0142] A Bandwidth Part (BWP) (which may also be referred to as a fractional bandwidth) may represent a subset of contiguous common resource blocks (RBs) for a given numerology on a given carrier, where the common RBs may be identified by their index relative to a common reference point of the carrier. PRBs may be defined in a given BWP and numbered within that BWP.

[0143] The BWP may include a BWP for UL (UL BWP) and a BWP for DL ​​(DL BWP). One or more BWPs may be configured for a UE within one carrier.

[0144] At least one of the configured BWPs may be active, and the UE may not expect to transmit or receive a given signal / channel outside the active BWP. Note that the terms "cell," "carrier," etc. in this disclosure may be read as "BWP."

[0145] The above-described structures of radio frames, subframes, slots, minislots, symbols, etc. are merely examples. For example, the number of subframes included in a radio frame, the number of slots per subframe or radio frame, the number of minislots included in a slot, the number of symbols and RBs included in a slot or minislot, the number of subcarriers included in an RB, the number of symbols in a TTI, the symbol length, the cyclic prefix (CP) length, etc. may be variously changed.

[0146] The terms "connected," "coupled," or any variation thereof, refer to any direct or indirect connection or coupling between two or more elements, and may include the presence of one or more intermediate elements between two elements that are "connected" or "coupled" to each other. The coupling or connection between elements may be physical, logical, or a combination thereof. For example, "connected" may be read as "access." As used in this disclosure, two elements may be considered to be "connected" or "coupled" to each other using one or more wires, cables, and / or printed electrical connections, as well as electromagnetic energy having wavelengths in the radio frequency range, microwave range, and optical (both visible and invisible) range, as some non-limiting and non-exhaustive examples.

[0147] The reference signal may also be abbreviated as Reference Signal (RS) and may be called a pilot depending on the applicable standard.

[0148] As used in this disclosure, the phrase "based on" does not mean "based only on," unless expressly stated otherwise. In other words, the phrase "based on" means both "based only on" and "based at least on."

[0149] The "means" in the configuration of each of the above devices may be replaced with "part," "circuit," "device," etc.

[0150] As used in this disclosure, any reference to an element using a designation such as "first," "second," etc. does not generally limit the quantity or order of those elements. These designations may be used in this disclosure as a convenient method of distinguishing between two or more elements. Thus, a reference to a first and a second element does not imply that only two elements may be employed therein or that the first element must precede the second element in some way.

[0151] When the terms "include," "including," and variations thereof are used in this disclosure, these terms are intended to be inclusive, similar to the term "comprising." Furthermore, when the term "or" is used in this disclosure, it is not intended to be an exclusive or.

[0152] In this disclosure, where articles are added by translation, such as a, an, and the in English, the disclosure may include that the nouns following these articles are in the plural form.

[0153] As used in this disclosure, the terms "determining" and "determining" may encompass a wide variety of actions. "Determining" and "determining" may include, for example, judging, calculating, computing, processing, deriving, investigating, looking up, searching, inquiring (e.g., searching a table, database, or other data structure), ascertaining, and the like. "Determining" and "determining" may also include receiving (e.g., receiving information), transmitting (e.g., sending information), input, output, accessing (e.g., accessing data in memory), and the like, all of which are considered to be "determining." "Determining" and "determining" may also include resolving, selecting, choosing, establishing, comparing, and the like, all of which are considered to be "determining." In other words, "judgment" and "decision" can include regarding some action as having been "judged" or "decided." Also, "judgment (decision)" can be interpreted as "assuming," "expecting," "considering," etc.

[0154] In the present disclosure, the term "A and B are different" may mean "A and B are different from each other." The term may also mean "A and B are each different from C." Terms such as "separate" and "coupled" may also be interpreted in the same way as "different."

[0155] 14 shows an example of the configuration of a vehicle 2001. As shown in Fig. 14, the vehicle 2001 includes a drive unit 2002, a steering unit 2003, an accelerator pedal 2004, a brake pedal 2005, a shift lever 2006, left and right front wheels 2007, left and right rear wheels 2008, an axle 2009, an electronic control unit 2010, various sensors 2021 to 2029, an information service unit 2012, and a communication module 2013.

[0156] The drive unit 2002 is composed of, for example, an engine, a motor, or a hybrid of an engine and a motor.

[0157] The steering unit 2003 includes at least a steering wheel (also called a handle) and is configured to steer at least one of the front wheels and the rear wheels based on the operation of the steering wheel operated by the user.

[0158] The electronic control unit 2010 is composed of a microprocessor 2031, a memory (ROM, RAM) 2032, and a communication port (IO port) 2033. Signals are input to the electronic control unit 2010 from various sensors 2021 to 2027 provided in the vehicle. The electronic control unit 2010 may also be called an ECU (Electronic Control Unit).

[0159] The signals from the various sensors 2021 to 2028 include a current signal from a current sensor 2021 that senses the current of the motor, a rotation speed signal of the front and rear wheels obtained by a rotation speed sensor 2022, an air pressure signal of the front and rear wheels obtained by an air pressure sensor 2023, a vehicle speed signal obtained by a vehicle speed sensor 2024, an acceleration signal obtained by an acceleration sensor 2025, an accelerator pedal depression amount signal obtained by an accelerator pedal sensor 2029, a brake pedal depression amount signal obtained by a brake pedal sensor 2026, a shift lever operation signal obtained by a shift lever sensor 2027, and a detection signal for detecting obstacles, vehicles, pedestrians, etc. obtained by an object detection sensor 2028.

[0160] The information service unit 2012 is composed of various devices, such as a car navigation system, an audio system, speakers, a television, and a radio, for providing various types of information such as driving information, traffic information, and entertainment information, and one or more ECUs for controlling these devices. The information service unit 2012 uses information obtained from external devices via the communication module 2013, etc., to provide various types of multimedia information and multimedia services to the occupants of the vehicle 1.

[0161] The driving assistance system unit 2030 is composed of various devices that provide functions for preventing accidents and reducing the driver's driving burden, such as millimeter-wave radar, LiDAR (Light Detection and Ranging), cameras, positioning locators (e.g., GNSS, etc.), map information (e.g., high-definition (HD) maps, autonomous vehicle (AV) maps, etc.), gyro systems (e.g., IMU (Inertial Measurement Unit), INS (Inertial Navigation System), etc.), AI (Artificial Intelligence) chips, and AI processors, as well as one or more ECUs that control these devices. The driving assistance system unit 2030 also transmits and receives various information via the communication module 2013 to realize driving assistance functions or autonomous driving functions.

[0162] The communication module 2013 can communicate with the microprocessor 2031 and components of the vehicle 1 via the communication port. For example, the communication module 2013 transmits and receives data via the communication port 2033 to and from a driving unit 2002, a steering unit 2003, an accelerator pedal 2004, a brake pedal 2005, a shift lever 2006, left and right front wheels 2007, left and right rear wheels 2008, an axle 2009, a microprocessor 2031 and memory (ROM, RAM) 2032 in the electronic control unit 2010, and sensors 2021 to 2028, which are provided in the vehicle 2001.

[0163] The communication module 2013 is a communication device that can be controlled by the microprocessor 2031 of the electronic control unit 2010 and can communicate with an external device. For example, it transmits and receives various information to and from the external device via wireless communication. The communication module 2013 may be located either inside or outside the electronic control unit 2010. The external device may be, for example, a base station, a mobile station, or the like.

[0164] The communication module 2013 transmits, via wireless communication to an external device, a current signal from the current sensor that is input to the electronic control unit 2010. The communication module 2013 also transmits, via wireless communication to an external device, the rotation speed signals of the front and rear wheels acquired by a rotation speed sensor 2022, the air pressure signals of the front and rear wheels acquired by an air pressure sensor 2023, the vehicle speed signal acquired by a vehicle speed sensor 2024, the acceleration signal acquired by an acceleration sensor 2025, the accelerator pedal depression amount signal acquired by an accelerator pedal sensor 2029, the brake pedal depression amount signal acquired by a brake pedal sensor 2026, the shift lever operation signal acquired by a shift lever sensor 2027, and the detection signals for detecting obstacles, vehicles, pedestrians, etc. acquired by an object detection sensor 2028, all of which are input to the electronic control unit 2010.

[0165] The communication module 2013 receives various information (traffic information, traffic signal information, vehicle distance information, etc.) transmitted from external devices and displays it on an information service unit 2012 provided in the vehicle. The communication module 2013 also stores the various information received from the external devices in a memory 2032 that can be used by the microprocessor 2031. Based on the information stored in the memory 2032, the microprocessor 2031 may control the drive unit 2002, steering unit 2003, accelerator pedal 2004, brake pedal 2005, shift lever 2006, left and right front wheels 2007, left and right rear wheels 2008, axle 2009, sensors 2021 to 2028, and the like provided in the vehicle 2001.

[0166] Although the present disclosure has been described in detail above, it is clear to those skilled in the art that the present disclosure is not limited to the embodiments described herein. The present disclosure can be implemented in modified and altered forms without departing from the spirit and scope of the present disclosure as defined by the claims. Therefore, the description of the present disclosure is intended to be illustrative and does not have any limiting meaning on the present disclosure.

[0167] (Additional Note) The above disclosure may be expressed as follows.

[0168] A first feature is a base station comprising: a transceiver unit that transmits and receives radio signals between the base station and a terminal that is simultaneously connected to the base station and another base station; and a control unit that requests the other base station to change the base station to which the terminal is connected, wherein the control unit requests the other base station to provide the number of counter values ​​for deriving a required security key each time the terminal changes its connection with the base station.

[0169] A second feature is a base station in the first feature, wherein the control unit predicts the number of counter values ​​using a learned model that has been learned based on information related to the terminal or other terminals.

[0170] A third feature is a base station according to the first or second feature, wherein the control unit predicts the number of times the terminal will change connection with the base station using a learned model based on information related to the terminal or other terminals.

[0171] A fourth feature is a base station comprising: a transceiver unit that transmits and receives radio signals between the base station and a terminal that is simultaneously connected to another base station; and a control unit that requests the other base station to change the base station to which the terminal is connected, wherein the control unit predicts a trajectory of the terminal using a learning model that has been trained based on information related to the terminal or other terminals, and the transceiver unit transmits the trajectory of the terminal to the other base station.

[0172] A fifth feature is a base station comprising: a transceiver unit that transmits to another base station a message related to the addition or change of a secondary node to which a terminal connects; and a control unit that includes in the message a security key required for the terminal to connect to the other base station, wherein the control unit includes in the message a counter value used by the terminal to derive the security key.

[0173] A sixth feature is a wireless communication method including: a transmitting / receiving step of transmitting and receiving a wireless signal between a base station and a terminal simultaneously connected to another base station; and a control step of requesting the other base station to change the base station to which the terminal is connected, wherein the control step requests the other base station to provide the number of counter values ​​for deriving a necessary security key each time the terminal changes its connection with a base station.

[0174] 10 Wireless communication system 20 NG-RAN 100 gNB 110 Transceiver unit 120 Generation unit 130 Prediction unit 140 HO unit 150 Control unit 200 UE 210 Transceiver unit 220 Generation unit 230 Control unit 1001 Processor 1002 Memory 1003 Storage 1004 Communication device 1005 Input device 1006 Output device 1007 Bus 2001 Vehicle 2002 Drive unit 2003 Steering unit 2004 Accelerator pedal 2005 Brake pedal 2006 Shift lever 2007 Left and right front wheels 2008 Left and right rear wheels 2009 Axle 2010 Electronic control unit 2012 Information service unit 2013 Communication module 2021 Current sensor 2022 Rotation speed sensor 2023 Air pressure sensor 2024 Vehicle speed sensor 2025 Acceleration sensor 2026 Brake pedal sensor 2027 Shift lever sensor 2028 Object detection sensor 2029 Accelerator pedal sensor 2030 Driving assistance system section 2031 Microprocessor 2032 Memory (ROM, RAM) 2033 Communication port

Claims

1. It is a base station, A transmitting unit that sends a message to other base stations regarding the addition of a secondary node to which a terminal will connect, The control unit includes in the message a security key necessary for the terminal to connect with the other base station, Equipped with, The control unit includes in the message a counter value for the terminal to derive the security key. Base station.

2. The control unit includes the security key and the counter value in the Conditional PSCell Addition Information Request in the message. The base station according to claim 1.

3. A receiving unit that receives a counter value from a base station, A control unit that derives a security key necessary to connect to another first base station from the aforementioned counter value, A terminal equipped with the following features.

4. The receiving unit receives from the base station another counter value different from the counter value, The control unit derives from the other counter values ​​other security keys necessary to connect to a second base station different from the other first base station. The terminal according to claim 3.

5. A wireless communication system comprising a base station and other base stations, The aforementioned base station is A transmitting unit that transmits a message to the aforementioned other base station regarding the addition of a secondary node to which a terminal is connected, The control unit includes in the message a security key necessary for the terminal to connect with the other base station, Equipped with, The control unit includes in the message a counter value for the terminal to derive the security key. The other base station includes a receiving unit that receives the message from the base station. Wireless communication system.

6. A wireless communication method performed by a base station, Send a message to other base stations regarding the addition of a secondary node to which the terminal will connect. The message includes the security key necessary for the terminal to connect with the other base station, The message includes a counter value for the terminal to derive the security key. Wireless communication method.