Terminal, network device, wireless communication system, and wireless communication method

Abstract

This terminal comprises: a reception unit that receives, from a first network, a paging signal requesting connection to the first network; and a control unit that executes a procedure for connection to the first network in accordance with the paging signal. After connecting to the first network, the reception unit receives, from the first network, information requesting connection to a second network different from the first network.

Description

Terminal, network device, wireless communication system, and wireless communication method

[0001] The present disclosure relates to a terminal, a network device, a wireless communication system, and a wireless communication method that support migration between two or more networks.

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

[0003] Prior to 5G, coordination between 4G Radio Access Network (RAN) and 5G RAN was studied in dual connectivity, in which a terminal (UE: User Equipment) connects to a 4G RAN node and a 5G RAN node (for example, Non-Patent Document 1).

[0004] 3GPP TS 36.423 V17.6.0, 3rd Generation Partnership Project,Technical Specification Group Radio Access Network, Evolved Universal Terrestrial Radio Access Network (E-UTRAN), X2 application protocol (X2AP) (Release 17)

[0005] Incidentally, in the migration from existing technology (hereinafter referred to as 5G) to new technology (hereinafter referred to as 6G), it is expected that the 5G core network (hereinafter referred to as 5GC) and the 6G core network (hereinafter referred to as 6GC) will cooperate with each other.

[0006] As a result of careful consideration, the inventors have found that when a function for cooperation between 5GC and 6GC is adopted and a case is assumed in which paging is sent in response to the arrival of DL data for the UE, it is necessary to consider a mechanism for appropriately triggering a configuration (dual stack) in which the UE connects to both 5GC and 6GC.

[0007] Therefore, the present disclosure has been made to solve the above-mentioned problems, and aims to provide a terminal, a network device, a wireless communication system, and a wireless communication method that can appropriately trigger a configuration (dual stack) in which the UE connects to both 5GC and 6GC when a case is assumed in which paging is sent in response to the arrival of DL data for the UE.

[0008] The disclosed aspect is a terminal comprising: a receiving unit that receives a paging signal from a first network requesting connection to the first network; and a control unit that executes a connection procedure to the first network in response to the paging signal, wherein the receiving unit receives information from the first network requesting connection to a second network different from the first network after connecting to the first network.

[0009] An aspect of the disclosure is a network device comprising: a transmitter in a cell belonging to a first network that transmits a paging signal requesting connection to the first network; and a control unit that assumes that a terminal will execute a connection procedure to the first network in response to the paging signal, wherein the transmitter transmits information to the terminal requesting connection to a second network different from the first network after the terminal connects to the first network.

[0010] An aspect of the disclosure is a wireless communication system comprising a terminal and a first network device provided in a first network, wherein the first network device transmits a paging signal requesting connection to the first network, the terminal executes a connection procedure to the first network in response to the paging signal, and the first network device transmits information to the terminal requesting connection to a second network different from the first network after the terminal connects to the first network.

[0011] An aspect of the disclosure is a wireless communication method comprising the steps of receiving a paging signal from a first network requesting connection to the first network, performing a connection procedure to the first network in response to the paging signal, and, after connecting to the first network, receiving information from the first network requesting connection to a second network different from the first network.

[0012] FIG. 1 is a diagram illustrating an overall schematic configuration of a wireless communication system 10. FIG. 2 is a diagram illustrating frequency ranges used in a cellular network. FIG. 3 is a diagram illustrating an example configuration of radio frames, subframes, and slots used in a cellular network. FIG. 4 is a functional block configuration diagram of a UE 200. FIG. 5 is a functional block configuration diagram of a network device 50. FIG. 6 is a diagram illustrating the problem and background. FIG. 7 is a diagram illustrating the problem and background. FIG. 8 is a diagram illustrating the problem and background. FIG. 9 is a diagram illustrating the problem and background. FIG. 10 is a diagram illustrating the problem and background. FIG. 11 is a diagram illustrating the problem and background. FIG. 12 is a diagram illustrating the problem and background. FIG. 13 is a diagram illustrating the problem and background. FIG. 14 is a diagram illustrating the problem and background. FIG. 15 is a diagram illustrating the problem and background. FIG. 16 is a diagram illustrating the problem and background. FIG. 17 is a diagram illustrating Operation Example 1. FIG. 18 is a diagram illustrating Operation Example 2. FIG. 19 is a diagram illustrating Operation Example 3. Fig. 20 is a diagram for explaining operation example 4. Fig. 21 is a diagram for explaining operation example 5. Fig. 22 is a diagram for explaining operation example 6. Fig. 23 is a diagram for explaining operation example 7. Fig. 24 is a diagram for explaining operation example 8. Fig. 25 is a diagram showing an example of the hardware configuration of the gNB 100 and the UE 200. Fig. 26 is a diagram showing an example of the configuration of a vehicle 2001.

[0013] 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.

[0014] [Embodiment] (1) Overall Schematic Configuration of Wireless Communication System Fig. 1 is an overall schematic configuration diagram of a wireless communication system 10 according to an embodiment. The wireless communication system 10 includes a terminal 200 (hereinafter referred to as UE (User Equipment) 200), a first network 10A, and a second network 10B.

[0015] The first network 10A has a radio access network 20A and a core network 30A. The radio access network 20A includes a base station 100A that performs radio communication with the UE 200. Note that the first network 10A may not have the radio access network 20A but may have the base station 100A. The first network 10A may not have the core network 30A. The base station 100A may be configured by a DU (Distributed Unit) and a CU (Central Unit). The DU may perform processing of layers below the MAC layer. The CU may perform processing above the PDCP layer.

[0016] The first network 10A may be a network conforming to a new technology (6G). 6G may be referred to as Beyond 5G or 5G Evolution. The first network 10A may be a network conforming to an existing technology (5G). 5G may be referred to as 5G New Radio (NR).

[0017] The second network 10B has a radio access network 20B and a core network 30B. The radio access network 20B includes a base station 100B that performs radio communication with the UE 200. Note that the second network 10B may not have the radio access network 20B but may have the base station 100B. The second network 10B may not have the core network 30B. The base station 100B may be configured by a DU and a CU.

[0018] The second network 10B may be a network conforming to existing technology (5G), which may be referred to as 5G New Radio (NR). The second network 10B may be a network conforming to new technology (6G), which may be referred to as Beyond 5G or 5G Evolution.

[0019] Here, the first network 10A and the second network 10B may have different radio access schemes. For example, the radio access scheme may be a cellular network radio access scheme called 5G, Beyond 5G, 5G Evolution, 6G, or the like.

[0020] First, the cellular network may support multiple frequency ranges (FR) as shown in Figure 2. For example, as shown in Figure 2, the cellular network may support FR1 and FR2. The frequency bands of each FR are as follows:

[0021] ・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 FR1 may use a sub-carrier spacing (SCS) of 15, 30, or 60 kHz and a bandwidth (BW) of 5 to 100 MHz. FR2 is a higher frequency than FR1, and may use an SCS of 60 kHz or 120 kHz (including 240 kHz) and a bandwidth (BW) of 50 to 400 MHz.

[0022] Furthermore, cellular networks may also support higher frequency bands than the FR2 frequency band, specifically, frequency bands above 52.6 GHz up to 71 GHz or 114.25 GHz.

[0023] Second, the cellular network may correspond to the radio frames, subframes and slots shown in FIG.

[0024] As shown in Figure 3, one slot consists of 14 symbols, and the larger (wider) the SCS, the shorter the symbol period (and slot period). In addition to 15 kHz, 30 kHz, 60 kHz, 120 kHz, and 240 kHz, the SCS may also use 480 kHz, 960 kHz, etc.

[0025] Furthermore, the number of symbols constituting one slot does not necessarily have to be 14 (for example, 28 symbols or 56 symbols). Furthermore, the number of slots per subframe may differ depending on the SCS.

[0026] The time direction (t) shown in Fig. 3 may be called a time domain, a symbol period, a symbol time, etc. The frequency direction may be called a frequency domain, a resource block, a subcarrier, a bandwidth part (BWP), etc.

[0027] (2) Functional Block Configuration of Wireless Communication System The functional block configuration of the wireless communication system 10 will be described below.

[0028] First, the functional block configuration of the UE 200 will be described.

[0029] Fig. 4 is a functional block diagram of UE 200. As shown in Fig. 4, UE 200 includes radio signal transmitting / receiving unit 210, amplifier unit 220, modem unit 230, control signal / reference signal processing unit 240, encoding / decoding unit 250, data transmitting / receiving unit 260, and control unit 270.

[0030] The radio signal transmission / reception unit 210 transmits and receives radio signals conforming to NR. The radio signal transmission / reception unit 210 supports Massive MIMO, CA that uses a bundle of multiple CCs, and DC that simultaneously communicates between a UE and two NG-RAN nodes.

[0031] The amplifier unit 220 is configured by a PA (Power Amplifier) / LNA (Low Noise Amplifier), etc. The amplifier unit 220 amplifies the signal output from the modulation / demodulation unit 230 to a predetermined power level. The amplifier unit 220 also amplifies the RF signal output from the radio signal transmission / reception unit 210.

[0032] The modem unit 230 performs data modulation / demodulation, transmission power setting, resource block allocation, etc. for each predetermined communication destination (gNB 100 or another gNB). The modem unit 230 may apply Cyclic Prefix-Orthogonal Frequency Division Multiplexing (CP-OFDM) / Discrete Fourier Transform - Spread (DFT-S-OFDM). Furthermore, DFT-S-OFDM may be used not only for the uplink (UL) but also for the downlink (DL).

[0033] The control signal and reference signal processor 240 executes processing related to various control signals transmitted and received by the UE 200 and processing related to various reference signals transmitted and received by the UE 200 .

[0034] Specifically, the control signal / reference signal processing unit 240 receives various control signals, for example, control signals of a radio resource control layer (RRC), transmitted via a predetermined control channel from the gNB 100. In addition, the control signal / reference signal processing unit 240 transmits various control signals to the gNB 100 via a predetermined control channel.

[0035] The control signal / reference signal processing unit 240 performs processing using reference signals (RS) such as a Demodulation Reference Signal (DM-RS) and a Phase Tracking Reference Signal (PT-RS).

[0036] DM-RS is a terminal-specific reference signal (pilot signal) known between the base station and the terminal to estimate the fading channel used for data demodulation. PT-RS is a terminal-specific reference signal intended to estimate phase noise, which is an issue in high frequency bands.

[0037] In addition to DM-RS and PT-RS, the reference signals may also include a Channel State Information-Reference Signal (CSI-RS), a Sounding Reference Signal (SRS), and a Positioning Reference Signal (PRS) for location information.

[0038] The channels include control channels and data channels, such as a PDCCH (Physical Downlink Control Channel), a PUCCH (Physical Uplink Control Channel), a RACH (Random Access Channel), a Downlink Control Information (DCI) including a Random Access Radio Network Temporary Identifier (RA-RNTI), and a Physical Broadcast Channel (PBCH).

[0039] Furthermore, the data channel includes a PDSCH (Physical Downlink Shared Channel) and a PUSCH (Physical Uplink Shared Channel). Data refers to data transmitted via the data channel. The data channel may be interpreted as a shared channel.

[0040] Here, the control signal and reference signal processor 240 may receive downlink control information (DCI). The DCI includes existing fields for storing DCI Formats, Carrier indicator (CI), BWP indicator, FDRA (Frequency Domain Resource Assignment), TDRA (Time Domain Resource Assignment), MCS (Modulation and Coding Scheme), HPN (HARQ Process Number), NDI (New Data Indicator), RV (Redundancy Version), and the like.

[0041] The value stored in the DCI Format field is an information element that specifies the format of the DCI. The value stored in the CI field is an information element that specifies the CC to which the DCI applies. The value stored in the BWP indicator field is an information element that specifies the BWP to which the DCI applies. The BWP that can be specified by the BWP indicator is set by an information element (BandwidthPart-Config) included in the RRC message. The value stored in the FDRA field is an information element that specifies the frequency domain resource to which the DCI applies. The frequency domain resource is identified by the value stored in the FDRA field and an information element (RA Type) included in the RRC message. The value stored in the TDRA field is an information element that specifies the time domain resource to which the DCI applies. The time domain resource is identified by the value stored in the TDRA field and information elements (pdsch-TimeDomainAllocationList, pusch-TimeDomainAllocationList) included in the RRC message. The time domain resource may be identified by the value stored in the TDRA field and a default table. The value stored in the MCS field is an information element that specifies the MCS to which the DCI applies. The MCS is identified by the value stored in the MCS and an MCS table. The MCS table may be specified by an RRC message or may be determined by RNTI scrambling. The value stored in the HPN field is an information element that specifies the HARQ process to which the DCI is applied. The value stored in the NDI field is an information element for specifying whether the data to which the DCI is applied is initial transmission data. The value stored in the RV field is an information element that specifies the redundancy of the data to which the DCI is applied.

[0042] The encoding / decoding unit 250 performs data division / concatenation and channel coding / decoding for each predetermined communication destination (gNB100 or another gNB).

[0043] Specifically, the encoding / decoding unit 250 divides the data output from the data transmitting / receiving unit 260 into pieces of a predetermined size, performs channel coding on the divided data, decodes the data output from the modem unit 230, and concatenates the decoded data.

[0044] The data transmitter / receiver 260 transmits and receives Protocol Data Units (PDUs) and Service Data Units (SDUs). Specifically, the data transmitter / receiver 260 assembles and disassembles PDUs / SDUs in multiple layers (such as a Medium Access Control layer (MAC), a Radio Link Control layer (RLC), and a Packet Data Convergence Protocol layer (PDCP)). The data transmitter / receiver 260 also performs data error correction and retransmission control based on Hybrid Automatic Repeat Request (HARQ).

[0045] The control unit 270 controls each functional block constituting the UE 200. The control unit 270 may execute communication to connect to at least one of the first network 10A and the second network 10B individually without assuming coordination between the first network 10A and the second network 10B. The control unit 270 may execute communication to connect to both the first network 10A and the second network 10B, assuming coordination between the first network 10A and the second network 10B.

[0046] In the embodiment, the control unit 270 may be configured as a control unit that, when receiving a paging signal from the first network 10A requesting connection to the first network 10A, executes a procedure for connecting to the first network 10A in response to the paging signal. The radio signal transceiver 210 may be configured as a receiving unit that receives a paging signal from the first network 10A requesting connection to the first network 10A. After the UE 200 connects to the first network 10A, the radio signal transceiver 210 may receive information (hereinafter, a connection request) from the first network 10A requesting connection to a second network 10B different from the first network 10A. The connection request may be included in an RRC message, a MAC CE, or information (e.g., DCI) transmitted via the PDCCH.

[0047] The procedure for connecting to the first network 10A in response to the paging signal may include a random access procedure (RA procedure). The RA procedure may include a 4-step RA procedure or a 2-step RA procedure.

[0048] The 4-step RA procedure may include transmitting Msg1, receiving Msg2, transmitting Msg3, receiving Msg4, and transmitting Msg5. Msg1 may be transmitted via a Physical Random Access Channel (PRACH). Msg1 may be referred to as a PRACH Preamble. Msg2 may be transmitted via a PDSCH. Msg2 may be referred to as a Random Access Response (RAR). Msg3 may be transmitted via a PUSCH. Msg3 may be referred to as an RRC Connection Request. Msg4 may be transmitted via a PDSCH. Msg4 may be referred to as an RRC Connection Setup. Msg5 may be transmitted via a PUSCH. Msg5 may be referred to as an RRC Setup Complete.

[0049] The 2-step RA procedure may include transmitting MsgA, receiving MsgB, and transmitting RRC Setup Complete. MsgA may include content that performs the same function as Msg1 and Msg3. MsgA may be transmitted via the PRACH. MsgB may include content that performs the same function as Msg2 and Msg4. MsgB may be transmitted via the PDSCH.

[0050] In the embodiment, aggregation of the first network 10A and the second network 10B may be assumed. The aggregation of the first network 10A and the second network 10B may be read as aggregation of the core network 30A and the core network 30B (CN Aggregation). CN Aggregation may be read as Dual Stack or Dual Registration. CN Aggregation may be aggregation of the UPF of the first network 10A and the UPF of the second network 10B. In such a case, the UPF of the first network 10A and the UPF of the second network 10B may be configured by a single UPF (Combo UPF). The UPF of the first network 10A and the UPF of the second network 10B may be configured by separate UPFs, and the separate UPFs may cooperate with each other.

[0051] Second, the functional block configuration of the network device 50 will be described. For example, the network device 50 is provided in the first network 10A or the second network 10B. That is, the network device 50 may be the base station 100A, may be a CU that constitutes part of the base station 100A, or may be a DU that constitutes part of the base station 100A. The network device 50 may be the base station 100B, may be a CU that constitutes part of the base station 100B, or may be a DU that constitutes part of the base station 100B.

[0052] As shown in FIG. 5, the network device 50 includes a receiving unit 51 , a transmitting unit 52 , and a control unit 53 .

[0053] The receiver 51 receives various signals from the UE 200. The receiver 51 may receive a control signal (PUCCH) or a data signal (PUSCH).

[0054] The transmitter 52 transmits various signals to the UE 200. The transmitter 52 may transmit a control signal (PDCCH) or a data signal (PDSCH).

[0055] In the embodiment, when the network device 50 is provided in the first network 10A, the transmitter 52 may configure a transmitter that transmits, in a cell belonging to the first network 10A, a paging signal requesting connection to the first network 10A. After the UE 200 connects to the first network 10A, the transmitter 52 may transmit, to the UE 200, information (a connection request) requesting connection to a second network 10B different from the first network 10A. The connection request may be included in an RRC message, a MAC CE, or information (e.g., DCI) transmitted via the PDCCH.

[0056] The control unit 53 controls each block constituting the network device 50. For example, when the network device 50 is provided in the first network 10A, the control unit 130 controls communication in the first network 10A. When the network device 50 is provided in the second network 10B, the control unit 130 controls communication in the second network 10B. In the embodiment, when the network device 50 is provided in the first network 10A, the control unit 53 may configure a control unit that assumes that the terminal executes a procedure for connecting to the first network 10A in response to a paging signal.

[0057] (3) Background and Issues First, we will explain the background to migration from existing technologies (4G, 5G, etc.) to new technologies (6G). When 6G is introduced, the following options are expected:

[0058] In Option 1, as shown in FIG. 6, a case is assumed in which 5G RAN, 6G RAN, 5GC, and 6GC are provided, and coordination between the 5G RAN and 6G RAN is performed.

[0059] In Option 2, as shown in FIG. 7, a case is assumed in which 5G RAN, 6G RAN, 5GC, and 6GC are provided, and coordination between 5GC and 6GC is performed.

[0060] In Option 3, as shown in FIG. 8, a case is assumed in which 5G RAN, 6G RAN, and 5GC are provided, and coordination between 5GC and 6GC is performed.

[0061] In Option 4, as shown in FIG. 9, a case is assumed in which 5G RAN, 6G RAN, and 6GC are provided, and coordination between 5GC and 6GC is performed.

[0062] In Option 5, as shown in FIG. 10 , a case is assumed in which 4G RAN, 5G RAN, 6G RAN, 4GC, 5GC, and 6GC are provided, and coordination is performed between the 4G RAN, 5G RAN, and 6G RAN.

[0063] In Option 6, as shown in FIG. 11 , a case is assumed in which 4G RAN, 5G RAN, 6G RAN, 4GC, 5GC, and 6GC are provided, and coordination between the 4GC, 5GC, and 6GC is performed.

[0064] In Option 7, as shown in FIG. 12, a case is assumed in which 4G RAN, 5G RAN, 6G RAN, and 5GC are provided, and coordination is performed between the 4G RAN, 5G RAN, and 6G RAN.

[0065] In Option 8, as shown in FIG. 13, a case is assumed in which 4G RAN, 5G RAN, 6G RAN, and 6GC are provided, and coordination is performed between the 4G RAN, 5G RAN, and 6G RAN.

[0066] In Option 9, as shown in FIG. 14, a case is assumed in which 4G RAN, 5G RAN, 6G RAN, and 4GC are provided, and coordination is performed between the 4G RAN, 5G RAN, and 6G RAN.

[0067] In the above-described case (e.g., option 2), as shown in Fig. 15, UE200 may register to both 5GC and 6GC (dual registration). Alternatively, UE200 may register to either 5GC or 6GC. In such a case, UE200 has a 5G protocol stack (physical layer (PHY), medium access control layer (MAC), radio link control layer (RLC), packet data convergence protocol layer (PDCP), radio resource control layer (RRC), and non-access layer (NAS)) and a 6G protocol stack (PHY, MAC, RLC, PDCP, RRC, and NAS) (dual stack). Note that coordination between 5G RAN and 6G RAN is not required.

[0068] Furthermore, as shown in Figure 16, the 5G UPF and the 6G UPF may be configured as one UPF (5G / 6G Combo UPF). The 5G / 6G Combo UPF may have a function of integrating data signals received via the 5G RAN and data signals received via the 6G RAN. The 5G / 6G Combo UPF may have a function of separating data signals transmitted via the 5G RAN and data signals transmitted via the 6G RAN.

[0069] Secondly, we will explain the issues that are expected in the above-mentioned coordination of 5GC and 6GC (CN Aggregation).

[0070] As a result of careful consideration, the inventors have found that when a function for cooperation between 5GC and 6GC is adopted and a case is assumed in which paging is sent in response to the arrival of DL data for the UE, it is necessary to consider a mechanism for appropriately triggering a configuration (dual stack) in which the UE connects to both 5GC and 6GC.

[0071] (4) Operational Example In order to solve the above-described problem, that is, to appropriately trigger a configuration in which a UE connects to both 5GC and 6GC (Dual Stack), the following operational example may be adopted.

[0072] (4.1) Operation Example 1 In Operation Example 1, a case will be described in which a paging signal is transmitted from either the first network 10A or the second network 10B. Since the paging signal is transmitted from either the first network 10A or the second network 10B, it is possible to reduce paging resources.

[0073] In Operation Example 1, a case will be described in which a Combo 5G / 6G SMF (Session Management System), a Combo 5G / 6G UPF, a 5G AMF (Access and Mobility Management Function), a 6G AMF, a 5G RAN, and a 6G RAN are provided. The 5G RAN is an example of a first network, and the 6G RAN is an example of a second network. A base station provided in the 5G RAN is an example of a first network device, and a base station provided in the 6G RAN is an example of a second network device. The 6G AMF is an example of an upper node of the second network. In Operation Example 1, the following operations are performed.

[0074] As shown in FIG. 17, in step S1-1, the 5G AMF transmits a paging signal (Paging) to the 5G RAN.

[0075] In step S1-2, the 5G RAN transmits a paging signal. In response to the paging signal, the UE performs a connection procedure (RA procedure) to the 5G RAN. In response to the connection to the 5G RAN, the UE transitions from the RRC IDLE state to the RRC CONNECTED state.

[0076] In step S1-3, the 5G RAN transmits information (connection request) requesting connection to the 6G RAN to the UE. The connection request may be considered as information instructing Dual Stack. The connection request may be included in an RRC message, a MAC CE, or information transmitted via the PDCCH (e.g., DCI).

[0077] Here, the 5G RAN may transmit a connection request when conditions are met. The conditions may include a first condition that the amount of DL data remaining in a RAN node buffer of the 5G RAN exceeds a threshold. The conditions may include a second condition that a measurement report reported from the UE to the 5G RAN indicates that there is a 6G cell that is better than a threshold. The conditions may include both the first condition and the second condition.

[0078] In step S1-4, the UE performs a procedure for connecting to the 6G RAN (RA procedure) in response to the connection request. The UE transmits a cause for connecting to the 6G RAN to the 6G RAN. The cause may be that Dual Stack is indicated. When a 4-step RA procedure is applied, the cause may be included in Msg1, Msg3, or Msg5. When a 2-step RA procedure is applied, the cause may be included in MsgA or RRC Setup Complete.

[0079] In step S1-5, the 6G RAN sends the reason for receiving from the UE to the 6G AMF. The reason may be included in an Initial UE message. The Initial UE message may include information identifying the UE.

[0080] In the first operational example, the UE executes a procedure for connecting to the 6G RAN (RA procedure) in response to a connection request. However, the first operational example is not limited to this. The UE may execute the procedure for connecting to the 6G RAN (RA procedure) without a connection request when a condition is met. The condition may include a third condition that the amount of UL data remaining in the UE's buffer exceeds a threshold. The condition may include a second condition that there is a 6G cell whose quality measured by the UE is better than a threshold. The condition may include both the third and fourth conditions. Even in such a case, the UE transmits a reason (Cause) for connecting to the 6G RAN to the 6G RAN. The reason may be due to dual stack.

[0081] (4.2) Operation Example 2 In Operation Example 2, a case will be described in which a paging signal is transmitted from either the first network 10A or the second network 10B. Since the paging signal is transmitted from either the first network 10A or the second network 10B, it is possible to reduce paging resources.

[0082] In Operation Example 2, a case will be described in which a Combo 5G / 6G SMF, a Combo 5G / 6G UPF, a 5G AMF, a 6G AMF, a 5G RAN, and a 6G RAN are provided. The 6G RAN is an example of a first network, and the 5G RAN is an example of a second network. A base station provided in the 6G RAN is an example of a first network device, and a base station provided in the 5G RAN is an example of a second network device. The 5G AMF is an example of an upper node of the second network. In Operation Example 2, the following operations are performed.

[0083] As shown in FIG. 18, in step S2-1, the 6G AMF transmits a paging signal (Paging) to the 6G RAN.

[0084] In step S2-2, the 6G RAN transmits a paging signal. In response to the paging signal, the UE performs a connection procedure (RA procedure) to the 6G RAN. In response to the connection to the 6G RAN, the UE transitions from the RRC IDLE state to the RRC CONNECTED state.

[0085] In step S2-3, the 6G RAN transmits information (connection request) requesting connection to the 5G RAN to the UE. The connection request may be considered as information instructing Dual Stack. The connection request may be included in an RRC message, a MAC CE, or information transmitted via the PDCCH (e.g., DCI).

[0086] Here, the 6G RAN may transmit a connection request when conditions are met. The conditions may include a first condition that the amount of DL data remaining in a RAN node buffer of the 6G RAN exceeds a threshold. The conditions may include a second condition that a measurement report reported from the UE to the 6G RAN indicates that there is a 5G cell that is better than a threshold. The conditions may include both the first condition and the second condition.

[0087] In step S2-4, the UE performs a procedure for connecting to the 5G RAN (RA procedure) in response to the connection request. The UE transmits a cause for connecting to the 5G RAN to the 5G RAN. The cause may be a reason that Dual Stack is indicated. When a 4-step RA procedure is applied, the cause may be included in Msg1, Msg3, or Msg5. When a 2-step RA procedure is applied, the cause may be included in MsgA or RRC Setup Complete.

[0088] In step S2-5, the 5G RAN transmits the reason for receiving from the UE to the 5G AMF. The reason may be included in an Initial UE message. The Initial UE message may include information identifying the UE.

[0089] In the second operation example, the UE executes a procedure for connecting to the 5G RAN (RA procedure) in response to a connection request. However, the second operation example is not limited to this. The UE may execute the procedure for connecting to the 5G RAN (RA procedure) without a connection request when conditions are met. The conditions may include a third condition that the amount of UL data remaining in the UE's buffer exceeds a threshold. The conditions may include a second condition that there is a 5G cell whose quality measured by the UE is better than a threshold. The conditions may include both the third and fourth conditions. Even in such a case, the UE transmits a reason (Cause) for connecting to the 5G RAN to the 5G RAN. The reason may be for dual stack.

[0090] (4.3) Operation Example 3 In Operation Example 3, a case will be described in which a paging signal is transmitted from either the first network 10A or the second network 10B. Since the paging signal is transmitted from either the first network 10A or the second network 10B, it is possible to reduce paging resources.

[0091] In Operation Example 3, a case will be described in which a Combo 5G / 6G SMF, a Combo 5G / 6G UPF, a 5G / 6G AMF, a 5G RAN, and a 6G RAN are provided. The 5G RAN is an example of a first network, and the 6G RAN is an example of a second network. A base station provided in the 5G RAN is an example of a first network device, and a base station provided in the 6G RAN is an example of a second network device. The 5G / 6G AMF is an example of an upper node of the second network. In Operation Example 3, the following operations are performed.

[0092] As shown in FIG. 19, in step S3-1, the 5G / 6G AMF transmits a paging signal (Paging) to the 5G RAN.

[0093] In step S3-2, the 5G RAN transmits a paging signal. In response to the paging signal, the UE performs a connection procedure (RA procedure) to the 5G RAN. In response to the connection to the 5G RAN, the UE transitions from the RRC IDLE state to the RRC CONNECTED state.

[0094] In step S3-3, the 5G RAN transmits information (connection request) requesting connection to the 6G RAN to the UE. The connection request may be considered as information instructing Dual Stack. The connection request may be included in an RRC message, a MAC CE, or information transmitted via the PDCCH (e.g., DCI).

[0095] Here, the 5G RAN may transmit a connection request when conditions are met. The conditions may include a first condition that the amount of DL data remaining in a RAN node buffer of the 5G RAN exceeds a threshold. The conditions may include a second condition that a measurement report reported from the UE to the 5G RAN indicates that there is a 6G cell that is better than a threshold. The conditions may include both the first condition and the second condition.

[0096] In step S3-4, the UE performs a procedure for connecting to the 6G RAN (RA procedure) in response to the connection request. The UE transmits a cause for connecting to the 6G RAN to the 6G RAN. The cause may be a reason that Dual Stack is indicated. When a 4-step RA procedure is applied, the cause may be included in Msg1, Msg3, or Msg5. When a 2-step RA procedure is applied, the cause may be included in MsgA or RRC Setup Complete.

[0097] In step S3-5, the 6G RAN sends the reason for receiving from the UE to the 5G / 6G AMF. The reason may be included in an Initial UE message. The Initial UE message may include information identifying the UE.

[0098] In the third operation example, the UE executes a procedure for connecting to the 6G RAN (RA procedure) in response to a connection request. However, the third operation example is not limited to this. The UE may execute the procedure for connecting to the 6G RAN (RA procedure) without a connection request when conditions are met. The conditions may include a third condition that the amount of UL data remaining in the UE's buffer exceeds a threshold. The conditions may include a second condition that there is a 6G cell whose quality measured by the UE is better than a threshold. The conditions may include both the third and fourth conditions. Even in such a case, the UE transmits a reason (Cause) for connecting to the 6G RAN to the 6G RAN. The reason may be due to dual stack.

[0099] (4.4) Operation Example 4 In Operation Example 4, a case will be described in which a paging signal is transmitted from either the first network 10A or the second network 10B. Since the paging signal is transmitted from either the first network 10A or the second network 10B, it is possible to reduce paging resources.

[0100] In Operation Example 4, a case will be described in which a Combo 5G / 6G SMF, a Combo 5G / 6G UPF, a 5G / 6G AMF, a 5G RAN, and a 6G RAN are provided. The 6G RAN is an example of a first network, and the 5G RAN is an example of a second network. A base station provided in the 6G RAN is an example of a first network device, and a base station provided in the 5G RAN is an example of a second network device. The 5G / 6G AMF is an example of an upper node of the second network. In Operation Example 4, the following operations are performed.

[0101] As shown in FIG. 20, in step S4-1, the 5G / 6G AMF transmits a paging signal (Paging) to the 6G RAN.

[0102] In step S4-2, the 6G RAN transmits a paging signal. In response to the paging signal, the UE performs a connection procedure (RA procedure) to the 6G RAN. In response to the connection to the 6G RAN, the UE transitions from the RRC IDLE state to the RRC CONNECTED state.

[0103] In step S4-3, the 6G RAN transmits information (connection request) requesting connection to the 5G RAN to the UE. The connection request may be considered as information instructing Dual Stack. The connection request may be included in an RRC message, a MAC CE, or information transmitted via the PDCCH (e.g., DCI).

[0104] Here, the 6G RAN may transmit a connection request when conditions are met. The conditions may include a first condition that the amount of DL data remaining in a RAN node buffer of the 6G RAN exceeds a threshold. The conditions may include a second condition that a measurement report reported from the UE to the 6G RAN indicates that there is a 5G cell that is better than a threshold. The conditions may include both the first condition and the second condition.

[0105] In step S4-4, the UE performs a procedure for connecting to the 5G RAN (RA procedure) in response to the connection request. The UE transmits a cause for connecting to the 5G RAN to the 5G RAN. The cause may be a reason that Dual Stack is indicated. When a 4-step RA procedure is applied, the cause may be included in Msg1, Msg3, or Msg5. When a 2-step RA procedure is applied, the cause may be included in MsgA or RRC Setup Complete.

[0106] In step S4-5, the 5G RAN transmits the reason for receiving from the UE to the 5G / 6G AMF. The reason may be included in an Initial UE message. The Initial UE message may include information identifying the UE.

[0107] In Operation Example 4, the UE executes a procedure for connecting to the 5G RAN (RA procedure) in response to a connection request. However, Operation Example 4 is not limited to this. The UE may execute the procedure for connecting to the 5G RAN (RA procedure) without a connection request when conditions are met. The conditions may include a third condition that the amount of UL data remaining in the UE's buffer exceeds a threshold. The conditions may include a second condition that there is a 5G cell whose quality measured by the UE is better than a threshold. The conditions may include both the third and fourth conditions. Even in such a case, the UE transmits a reason (Cause) for connecting to the 5G RAN to the 5G RAN. The reason may be due to dual stack.

[0108] (4.5) Operation Example 5 In Operation Example 5, a case will be described in which a paging signal is transmitted from both the first network 10A and the second network 10B. Since a paging signal is transmitted from both the first network 10A and the second network 10B, Operation Example 5 will describe a case in which Combo 5G / 6G SMF, Combo 5G / 6G UPF, 5G AMF, 6G AMF, 5G RAN, and 6G RAN are provided. In Operation Example 5, the following operations are performed.

[0109] As shown in FIG. 21, in step S5-1, the 5G AMF transmits a paging signal (Paging) to the 5G RAN.

[0110] In step S5-2, the 5G RAN transmits a paging signal. The paging signal may include information indicating Dual Stack. In response to the paging signal, the UE performs a connection procedure (RA procedure) to the 5G RAN. In response to the connection to the 5G RAN, the UE transitions from the RRC IDLE state to the RRC CONNECTED state.

[0111] Here, the UE may transmit a cause for connecting to the 5G RAN to the 5G RAN. The cause may be that Dual Stack is indicated. When a 4-step RA procedure is applied, the cause may be included in Msg1, Msg3, or Msg5. When a 2-step RA procedure is applied, the cause may be included in MsgA or RRC Setup Complete.

[0112] In step S5-3, the 6G AMF transmits a paging signal (Paging) to the 6G RAN.

[0113] In step S5-4, the 6G RAN transmits a paging signal. The paging signal may include information indicating Dual Stack. In response to the paging signal, the UE executes a procedure for connecting to the 6G RAN (RA procedure). In response to the connection to the 6G RAN, the UE transitions from the RRC IDLE state to the RRC CONNECTED state.

[0114] Here, the UE may transmit a cause for connecting to the 6G RAN to the 6G RAN. The cause may be that Dual Stack is indicated. When a 4-step RA procedure is applied, the cause may be included in Msg1, Msg3, or Msg5. When a 2-step RA procedure is applied, the cause may be included in MsgA or RRC Setup Complete.

[0115] In the sixth operational example, the processes of steps S5-1 and S5-2 may be performed after the processes of steps S5-3 and S5-4, or may be performed simultaneously with the processes of steps S5-1 and S5-2.

[0116] (4.6) Operation Example 6 In Operation Example 6, a case will be described in which a paging signal is transmitted from both the first network 10A and the second network 10B. Since a paging signal is transmitted from both the first network 10A and the second network 10B, Operation Example 6 will describe a case in which Combo 5G / 6G SMF, Combo 5G / 6G UPF, 5G AMF, 6G AMF, 5G RAN, and 6G RAN are provided. In Operation Example 6, the following operations are performed.

[0117] As shown in FIG. 22, in step S6-1, the 5G AMF transmits a paging signal (Paging) to the 5G RAN.

[0118] In step S6-2, the 5G RAN transmits a paging signal. The paging signal may include information indicating Dual Stack. In response to the paging signal, the UE performs a connection procedure (RA procedure) to the 5G RAN. In response to the connection to the 5G RAN, the UE transitions from the RRC IDLE state to the RRC CONNECTED state.

[0119] Here, the UE may transmit a cause for connecting to the 5G RAN to the 5G RAN. The cause may be that Dual Stack is indicated. When a 4-step RA procedure is applied, the cause may be included in Msg1, Msg3, or Msg5. When a 2-step RA procedure is applied, the cause may be included in MsgA or RRC Setup Complete.

[0120] In step S6-3, the 5G RAN forwards a paging signal to the 6G RAN. For example, the 5G RAN forwards the paging signal to the 6G RAN via the XN interface. The processing of step S6-3 may be performed before step S6-2.

[0121] In step S6-4, the 6G RAN transmits a paging signal. The paging signal may include information indicating Dual Stack. In response to the paging signal, the UE performs a connection procedure (RA procedure) to the 6G RAN. In response to the connection to the 6G RAN, the UE transitions from an RRC IDLE state to an RRC CONNECTED state for the 6G RAN.

[0122] Here, the UE may transmit a cause for connecting to the 6G RAN to the 6G RAN. The cause may be that Dual Stack is indicated. When a 4-step RA procedure is applied, the cause may be included in Msg1, Msg3, or Msg5. When a 2-step RA procedure is applied, the cause may be included in MsgA or RRC Setup Complete.

[0123] In Operation Example 6, the paging signal is transmitted from the 5G AMF to the 5G RAN and forwarded from the 5G RAN to the 6G RAN, but Operation Example 6 is not limited thereto. For example, the paging signal may be transmitted from the 6G AMF to the 6G RAN and forwarded from the 6G RAN to the 5G RAN.

[0124] (4.7) Operation Example 7 In Operation Example 7, a case will be described in which a paging signal is transmitted from both the first network 10A and the second network 10B. Since a paging signal is transmitted from both the first network 10A and the second network 10B, Operation Example 7 will describe a case in which a combo 5G / 6G SMF, a combo 5G / 6G UPF, a 5G / 6G AMF, a 5G RAN, and a 6G RAN are provided. In Operation Example 7, the following operations are performed.

[0125] As shown in FIG. 23, in step S7-1, the 5G / 6G AMF transmits a paging signal (Paging) to the 5G RAN.

[0126] In step S7-2, the 5G RAN transmits a paging signal. The paging signal may include information indicating Dual Stack. In response to the paging signal, the UE performs a connection procedure (RA procedure) to the 5G RAN. In response to the connection to the 5G RAN, the UE transitions from the RRC IDLE state to the RRC CONNECTED state.

[0127] Here, the UE may transmit a cause for connecting to the 5G RAN to the 5G RAN. The cause may be that Dual Stack is indicated. When a 4-step RA procedure is applied, the cause may be included in Msg1, Msg3, or Msg5. When a 2-step RA procedure is applied, the cause may be included in MsgA or RRC Setup Complete.

[0128] In step S7-3, the 5G / 6G AMF transmits a paging signal (Paging) to the 6G RAN.

[0129] In step S7-4, the 6G RAN transmits a paging signal. The paging signal may include information indicating Dual Stack. In response to the paging signal, the UE performs a connection procedure (RA procedure) to the 6G RAN. In response to the connection to the 6G RAN, the UE transitions from the RRC IDLE state to the RRC CONNECTED state.

[0130] Here, the UE may transmit a cause for connecting to the 6G RAN to the 6G RAN. The cause may be that Dual Stack is indicated. When a 4-step RA procedure is applied, the cause may be included in Msg1, Msg3, or Msg5. When a 2-step RA procedure is applied, the cause may be included in MsgA or RRC Setup Complete.

[0131] In the seventh operational example, the processes of steps S7-1 and S7-2 may be performed after the processes of steps S7-3 and S7-4, or may be performed simultaneously with the processes of steps S7-1 and S7-2.

[0132] (4.8) Operation Example 8 In Operation Example 8, a case will be described in which a paging signal is transmitted from both the first network 10A and the second network 10B. Since a paging signal is transmitted from both the first network 10A and the second network 10B, Operation Example 8 will describe a case in which a combo 5G / 6G SMF, a combo 5G / 6G UPF, a 5G / 6G AMF, a 5G RAN, and a 6G RAN are provided. In Operation Example 8, the following operations are performed.

[0133] As shown in FIG. 24, in step S8-1, the 5G / 6G AMF transmits a paging signal (Paging) to the 5G RAN.

[0134] In step S8-2, the 5G RAN transmits a paging signal. The paging signal may include information indicating Dual Stack. In response to the paging signal, the UE performs a connection procedure (RA procedure) to the 5G RAN. In response to the connection to the 5G RAN, the UE transitions from the RRC IDLE state to the RRC CONNECTED state.

[0135] Here, the UE may transmit a cause for connecting to the 5G RAN to the 5G RAN. The cause may be that Dual Stack is indicated. When a 4-step RA procedure is applied, the cause may be included in Msg1, Msg3, or Msg5. When a 2-step RA procedure is applied, the cause may be included in MsgA or RRC Setup Complete.

[0136] In step S8-3, the 5G RAN forwards a paging signal to the 6G RAN. For example, the 5G RAN forwards the paging signal to the 6G RAN via the XN interface. The processing of step S8-3 may be performed before step S8-2.

[0137] In step S8-4, the 6G RAN transmits a paging signal. The paging signal may include information indicating Dual Stack. In response to the paging signal, the UE performs a connection procedure (RA procedure) to the 6G RAN. In response to the connection to the 6G RAN, the UE transitions from an RRC IDLE state to an RRC CONNECTED state for the 6G RAN.

[0138] Here, the UE may transmit a cause for connecting to the 6G RAN to the 6G RAN. The cause may be that Dual Stack is indicated. When a 4-step RA procedure is applied, the cause may be included in Msg1, Msg3, or Msg5. When a 2-step RA procedure is applied, the cause may be included in MsgA or RRC Setup Complete.

[0139] In Operation Example 8, the paging signal is transmitted from the 5G AMF to the 5G RAN and forwarded from the 5G RAN to the 6G RAN, but Operation Example 8 is not limited thereto. For example, the paging signal may be transmitted from the 6G AMF to the 6G RAN and forwarded from the 6G RAN to the 5G RAN.

[0140] (4.9) UE Capability In order to apply the above-described operation examples 1 to 4, the following new UE capability and report signaling (and RRC configuration) may be defined for each UE / FR / FC, etc.

[0141] Whether or not to support the execution of a procedure to connect to 6G RAN (RA procedure) in response to a connection request (Operation Example 1, Operation Example 3) Whether or not to support the execution of a procedure to connect to 6G RAN autonomously by the UE when conditions are met (Operation Example 1, Operation Example 3) Whether or not to support the transmission of a reason (Cause) for connecting to 6G RAN (Operation Example 1, Operation Example 3) Whether or not to support the execution of a procedure to connect to 5G RAN in response to a connection request (RA procedure) (Operation Example 2, Operation Example 4) Whether or not to support the execution of a procedure to connect to 5G RAN autonomously by the UE when conditions are met (Operation Example 2, Operation Example 4) Whether or not to support the transmission of a reason (Cause) for connecting to 5G RAN (Operation Example 2, Operation Example 4)

[0142] (5) Actions and Effects In the embodiment, when the UE 200 receives a paging signal requesting connection to the first network 10A, the UE 200 executes a connection procedure to the first network 10A, and after connecting to the first network 10A, receives information (a connection request) from the first network 10A requesting connection to the second network 10B (see Operation Example 1-4). With this configuration, the connection request can be a dual stack instruction, so that dual stack can be appropriately triggered while suppressing paging signal resources.

[0143] In the embodiment, the UE 200 receives paging signals from both the first network 10A and the second network 10B (see Operational Example 5-8). Furthermore, a method for transmitting the paging signal is clarified. With this configuration, the Dual Stack can be appropriately triggered.

[0144] In the embodiment, when the UE 200 connects to the second network 10B in response to a connection request received from the first network 10A, the UE 200 transmits a reason for connecting to the second network 10B to the second network 10B. With this configuration, the second network 10B can determine whether the connection does not assume coordination between the first network 10A and the second network 10B, or whether the connection assumes coordination between the first network 10A and the second network 10B.

[0145] (6) 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.

[0146] 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.

[0147] 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.

[0148] Furthermore, the above-described network device 50 and UE 200 (the device) may function as a computer that performs processing of the wireless communication method of the present disclosure. Fig. 25 is a diagram showing an example of the hardware configuration of the device. As shown in Fig. 25, the device 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.

[0149] 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.

[0150] Each functional block of the device (see FIG. 4) is realized by any hardware element of the computer device or a combination of the hardware elements.

[0151] 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.

[0152] 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.

[0153] 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.

[0154] 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.

[0155] 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.

[0156] 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.

[0157] 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).

[0158] 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).

[0159] 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.

[0160] 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.

[0161] 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.

[0162] 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.

[0163] 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.

[0164] 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.

[0165] 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.

[0166] 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.

[0167] 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).

[0168] 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).

[0169] 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.

[0170] 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.

[0171] 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.

[0172] 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.

[0173] As used in this disclosure, the terms "system" and "network" are used interchangeably.

[0174] 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.

[0175] 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.

[0176] 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.

[0177] 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)).

[0178] 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.

[0179] In this disclosure, the terms "Mobile Station (MS)," "user terminal," "User Equipment (UE)," "terminal," etc. may be used interchangeably.

[0180] 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.

[0181] 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.

[0182] 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.

[0183] 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.

[0184] A radio frame may be made up of one or more frames in the time domain, each of which may be called a subframe.

[0185] 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.

[0186] 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.

[0187] 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.

[0188] 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.

[0189] 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.

[0190] 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.

[0191] 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.

[0192] 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.

[0193] 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.

[0194] 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.

[0195] 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.

[0196] 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.

[0197] 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.

[0198] 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.

[0199] 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.

[0200] 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.

[0201] 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.

[0202] At least one of the configured BWPs may be active, and the UE may not expect to transmit or receive a predetermined signal / channel outside the active BWP. Note that the terms "cell," "carrier," etc. in this disclosure may be read as "BWP."

[0203] 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.

[0204] 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.

[0205] The reference signal may also be abbreviated as Reference Signal (RS) and may be called a pilot depending on the applicable standard.

[0206] 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."

[0207] The "means" in the configuration of each of the above devices may be replaced with "part," "circuit," "device," etc.

[0208] 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.

[0209] 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.

[0210] 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.

[0211] 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 in 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. Furthermore, "judgment" and "decision" can include regarding resolving, selecting, choosing, establishing, comparing, etc. as having been "judged" or "decided." In other words, "judgment" and "decision" can include regarding some action as having been "judged" or "decided." Furthermore, "judgment (decision)" can be interpreted as "assuming," "expecting," "considering," etc.

[0212] 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."

[0213] 26 shows an example of the configuration of a vehicle 2001. As shown in Fig. 26, 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.

[0214] The drive unit 2002 is composed of, for example, an engine, a motor, or a hybrid of an engine and a motor.

[0215] 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.

[0216] 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).

[0217] 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.

[0218] 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.

[0219] 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.

[0220] 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.

[0221] 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.

[0222] 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.

[0223] 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.

[0224] 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.

[0225] (Additional Note) The above disclosure may be expressed as follows.

[0226] A first feature is a terminal comprising: a receiving unit that receives a paging signal from a first network requesting connection to the first network; and a control unit that executes a procedure for connecting to the first network in response to the paging signal, wherein the receiving unit receives information from the first network requesting connection to a second network different from the first network after connecting to the first network.

[0227] A second feature is that, in the first feature, the terminal further includes a transmitting unit that transmits a reason for connecting to the second network to the second network after receiving information requesting connection to the second network.

[0228] A third feature is a network device comprising: a transmitter that transmits, in a cell belonging to a first network, a paging signal requesting connection to the first network; and a control unit that assumes that a terminal will execute a procedure for connecting to the first network in response to the paging signal, wherein the transmitter transmits, to the terminal, information requesting connection to a second network different from the first network after the terminal connects to the first network.

[0229] A fourth feature is a wireless communication system comprising a terminal and a first network device provided in a first network, wherein the first network device transmits a paging signal requesting connection to the first network, the terminal executes a connection procedure to the first network in response to the paging signal, and the first network device transmits information to the terminal requesting connection to a second network different from the first network after the terminal connects to the first network.

[0230] A fifth feature is the wireless communication system of the fourth feature, further comprising a second network device provided in the second network, wherein the terminal, after receiving information requesting connection to the second network, transmits a reason for connecting to the second network to the second network device, and the second network device transmits the reason received from the terminal to an upper node of the second network.

[0231] A sixth feature is a wireless communication method including the steps of receiving a paging signal from a first network requesting connection to the first network, performing a connection procedure to the first network in response to the paging signal, and, after connecting to the first network, receiving information from the first network requesting connection to a second network different from the first network.

[0232] 10 Wireless communication system 10A First network 10B Second network 20A, 20B Wireless access network 30A, 30B Core network 50 Network device 51 Receiving unit 52 Transmitting unit 53 Control unit 100A, 100B Base station 200 UE 210 Wireless signal transmitting / receiving unit 220 Amplifying unit 230 Modulation / demodulation unit 240 Control signal / reference signal processing unit 250 Encoding / decoding unit 260 Data transmitting / receiving unit 270 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 RPM 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 unit 2031 Microprocessor 2032 Memory (ROM, RAM) 2033 Communication port

Claims

1. A terminal comprising: a receiving unit that receives a paging signal from a first network requesting connection to the first network; and a control unit that executes a procedure for connecting to the first network in response to the paging signal, wherein the receiving unit receives information from the first network requesting connection to a second network different from the first network after connecting to the first network.

2. The terminal according to claim 1, further comprising a transmitting unit that transmits a reason for connecting to the second network to the second network after receiving information requesting connection to the second network.

3. A network device comprising: a transmitter in a cell belonging to a first network that transmits a paging signal requesting connection to the first network; and a control unit that assumes that a terminal will execute a procedure for connecting to the first network in response to the paging signal, wherein the transmitter transmits information to the terminal requesting connection to a second network different from the first network after the terminal has connected to the first network.

4. A wireless communication system comprising a terminal and a first network device provided in a first network, wherein the first network device transmits a paging signal requesting connection to the first network, the terminal executes a procedure for connecting to the first network in response to the paging signal, and the first network device transmits information to the terminal requesting connection to a second network different from the first network after the terminal has connected to the first network.

5. The wireless communication system according to claim 4, further comprising a second network device provided in the second network, wherein the terminal, after receiving information requesting connection to the second network, transmits a reason for connecting to the second network to the second network device, and the second network device transmits the reason received from the terminal to an upper node of the second network.

6. A wireless communication method comprising the steps of: receiving a paging signal from a first network requesting connection to the first network; performing a connection procedure to the first network in response to the paging signal; and, after connecting to the first network, receiving information from the first network requesting connection to a second network different from the first network.

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