Wireless communication device, wireless communication system, and information management method

Abstract

A wireless communication device (100) has a control unit (120) that, when establishing communication with another wireless communication device (200) in a non-communication mode, can perform control: to generate, regardless of whether the other wireless communication device (200) retains second identification information among identification information for enabling simultaneous identification of the own device (100) and the other wireless communication device (200), first identification information among the identification information; and to notify the other wireless communication device (200) of the generated first identification information.

Description

[Technical field]

[0001] The present invention relates to a wireless communication device, a wireless communication system, and an information management method. [Background technology]

[0002] Generally, in a wireless communication system, processing of the RRC (Radio Resource Control) layer is performed. In the RRC layer processing, for example, connection setting, change, release, etc. are performed between a base station device and a terminal device. For example, in LTE (Long Term Evolution) or LTE-A (LTE-Advanced), which are standard technologies for 4G, RRC connected mode (RRC_CONNECTED) and RRC idle mode (RRC_IDLE) are specified as the states of the RRC layer. The RRC connected mode is, for example, a mode in which data communication can be performed between a base station device and a terminal device. The RRC idle mode is, for example, a mode in which data communication is not performed between a base station device and a terminal device, and a mode in which the terminal device is in a power saving state.

[0003] In the fifth generation mobile communication (5G or NR (New Radio)), in addition to the RRC connected mode and the RRC idle mode, the RRC inactive mode (RRC_INACTIVE) is introduced. The RRC inactive mode is a mode that has the same low power consumption as the RRC idle mode and can quickly transition to the RRC connected mode when transmitting data. In the RRC inactive mode, the context of the terminal device (hereinafter referred to as "UE context") is held in the base station device. The UE context is identification information that identifies information about the terminal device, such as the location, communication capabilities, and various parameters of the terminal device. In this way, since the UE context is held in the base station device, even in the RRC inactive mode, the terminal device is considered to be connected to the base station device by the core network. As a result, when the terminal device returns from the RRC inactive mode to the RRC connected mode, the transmission and reception of signals between the base station device and the core network is omitted, and a quick transition to the RRC connected mode is realized. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Special Publication No. 2020-512762 [Patent Document 2] Special Publication No. 2019-535201 [Non-patent literature]

[0005] [Non-Patent Document 1] 3GPP TS36.133 V17.1.0(2021-03) [Non-Patent Document 2] 3GPP TS36.211 V16.5.0(2021-03) [Non-Patent Document 3] 3GPP TS36.212 V16.5.0(2021-03) [Non-Patent Document 4] 3GPP TS36.213 V16.5.0(2021-03)

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[0006] Incidentally, for example, when a terminal device moves during the RRC inactive mode and returns to the RRC connected mode within the communication range of a different base station device, the destination base station device requests and acquires a UE context from the source base station device (e.g., referred to as an "anchor" base station). The destination base station device then resumes communication with the terminal device using the UE context acquired from the source base station device. Similarly, for example, when the upper device of the core network under its jurisdiction is changed due to the movement of the terminal device, the destination upper device acquires the UE context from the source upper device.

[0007] However, the above-mentioned UE context management method has a problem that a communication delay occurs due to a search for a UE context, and the method has low adaptability. That is, for example, when a terminal device in an RRC inactive mode moves across base station devices or upper devices, the destination base station device or upper device searches for a base station device or upper device that holds the UE context, and acquires the UE context from the base station device or upper device. Therefore, when the terminal device returns to the RRC connected mode under the destination base station device or upper device, a delay occurs until the terminal device returns to the RRC connected mode and starts communication.

[0008] In addition, when the UE context is transferred, signaling related to the transfer of the UE context occurs between the base station device or upper device of the destination and the base station device or upper device of the source, and the processing load of the base station device and the upper device increases with the increase in signaling. Thus, the above-mentioned UE context management method has a problem of low adaptability to various situations, since communication delays occur and the processing load increases when a situation occurs, such as when the terminal device moves.

[0009] The disclosed technology has been made in consideration of the above points, and has an object to provide a wireless communication device, a wireless communication system, and an information management method that can improve adaptability to various situations. [Means for solving the problem]

[0010] In one aspect, the wireless communication device disclosed in the present application has a control unit that, when establishing communication with another wireless communication device in a non-communication mode, generates first identification information among identification information that can simultaneously identify the device itself and the other wireless communication device, regardless of whether the other wireless communication device holds second identification information among the identification information, and is capable of controlling the generation of the generated first identification information to be notified to the other wireless communication device. Effect of the Invention

[0011] According to one aspect of the wireless communication device, the wireless communication system, and the information management method disclosed in the present application, it is possible to improve adaptability to various situations. [Brief description of the drawings]

[0012] [Figure 1] FIG. 1 is a diagram illustrating an example of a configuration of a wireless communication system according to a first embodiment. [Diagram 2] FIG. 2 is a diagram illustrating a configuration example of a wireless communication system according to the second embodiment. [Diagram 3] FIG. 3 is a block diagram showing the configuration of the base station device. [Figure 4] FIG. 4 is a block diagram showing the configuration of a terminal device. [Diagram 5] FIG. 5 is a sequence diagram showing an information management method according to the second embodiment. [Figure 6] FIG. 6 is a sequence diagram showing a specific example of a procedure for registering a context. [Figure 7] FIG. 7 is a sequence diagram showing the paging process. [Figure 8] FIG. 8 is a sequence diagram showing an information management method according to the third embodiment. [Figure 9] FIG. 9 is a diagram showing a specific example of movement of a terminal device. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] Hereinafter, embodiments of a wireless communication device, a wireless communication system, and an information management method disclosed in the present application will be described in detail with reference to the drawings. Note that the present invention is not limited to the embodiments.

[0014] (Embodiment 1) Fig. 1 is a diagram showing a configuration example of a wireless communication system according to embodiment 1. The wireless communication system shown in Fig. 1 includes a plurality of base station devices 100 and terminal devices 200 connected to a core network. The core network also includes a first higher level device 10 and a second higher level device 20.

[0015] The first higher level equipment 10 manages sessions related to communication of the terminal device 200. The second higher level equipment 20 manages security and the location of the terminal device 200. A plurality of second higher level equipment 20 are arranged in the core network, and each second higher level equipment 20 accepts registration of a UE context for each SIM (Subscriber Identity Module) of the terminal device 200 and holds the registered UE context. Therefore, a plurality of UE contexts can be registered in the core network for the SIM of one terminal device 200.

[0016] The base station apparatus 100 is a wireless communication apparatus that is connected to a core network and can wirelessly communicate with a terminal apparatus 200 located within a communication range. Although not shown in the figure, the base station apparatus 100 is connected to each other by, for example, an X2 interface or an Xn interface. When establishing communication with a terminal apparatus 200 in a non-communication mode such as an RRC inactive mode, the base station apparatus 100 can generate a UE context for the terminal apparatus 200 and notify the terminal apparatus 200 of the UE context, regardless of whether the terminal apparatus 200 already holds a UE context. That is, the base station apparatus 100 can generate a new UE context and notify the terminal apparatus 200 of the UE context, regardless of whether another base station apparatus 100 has already notified the terminal apparatus 200 of the UE context. In addition, the base station apparatus 100 holds a UE context related to the notification to the terminal apparatus 200. For this reason, multiple UE contexts can be held by multiple base station apparatuses 100 for the SIM of one terminal apparatus 200.

[0017] The UE context held by the base station device 100 for the terminal device 200 is identified by identification information capable of simultaneously identifying the base station device 100 and the terminal device 200. As such identification information, for example, an I-RNTI (Inactive-Radio Network Temporary Identifier) ​​can be used. In this way, since the UE context can be identified by, for example, the I-RNTI, it is possible to uniquely identify each of the multiple UE contexts related to the SIM of one terminal device 200.

[0018] The terminal device 200 is a wireless communication device capable of wireless communication with the base station device 100. The terminal device 200 can operate by switching between a communication mode such as an RRC connected mode and a non-communication mode such as an RRC inactive mode. When establishing communication with the base station device 100 in the non-communication mode, the terminal device 200 can be notified of identification information of a UE context generated by the base station device 100, regardless of whether the terminal device 200 already holds a UE context. That is, the terminal device 200 can hold identification information of a UE context notified from a new base station device 100, regardless of whether the terminal device 200 has already been notified of identification information of a UE context from another base station device 100.

[0019] When the terminal device 200 connects to the first base station device 100, the first base station device 100 generates identification information of a UE context capable of simultaneously identifying the terminal device 200 and the first base station device 100, holds the UE context, and notifies the identification information to the terminal device 200. The terminal device 200 holds the identification information of the UE context notified from the first base station device 100.

[0020] Then, for example, when the terminal device 200 moves and connects to the second base station device 100, the second base station device 100 generates identification information of a UE context that can simultaneously identify the terminal device 200 and the second base station device 100, regardless of whether the terminal device 200 already holds identification information of the UE context, and can hold the UE context and notify the identification information to the terminal device 200. The terminal device 200 can hold the identification information of the UE context notified from the second base station device 100.

[0021] As described above, according to the present embodiment, when a terminal device connects to a base station device or a higher-level device, regardless of whether or not the identification information of the UE context has already been held, the identification information of the UE context can be newly generated and notified to the terminal device. In other words, for the SIM of one terminal device, multiple UE contexts can be held by multiple base station devices, and the identification information of these UE contexts is notified to the terminal device. Therefore, even when a terminal device connects to multiple base station devices or higher-level devices, each base station device or higher-level device holds the UE context, so that the transfer of the UE context is not required when communicating with the terminal device, and adaptability to various situations can be improved.

[0022] (Embodiment 2) Fig. 2 is a diagram showing a configuration example of a wireless communication system according to embodiment 2. In Fig. 2, the same components as in Fig. 1 are denoted by the same reference numerals. The wireless communication system shown in Fig. 2 has a plurality of base station devices 100 and terminal devices 200 connected to a core network. In addition, the core network has a Session Management Function (SMF) 15 and an Access and Mobility management Function (AMF) 25.

[0023] The SMF 15 manages sessions related to communication of the terminal device 200. Specifically, when downlink data (hereinafter abbreviated as "DL data") addressed to the terminal device 200 occurs, the SMF 15 notifies the AMF 25 that the DL data has occurred.

[0024] The AMF 25 manages the security and location of the terminal device 200. Each AMF 25 accepts registration of a UE context for each SIM of the terminal device 200 and holds the registered UE context. When the AMF 25 is notified of the occurrence of DL data from the SMF 15, it executes paging to call the terminal device 200 that is the destination of the DL data.

[0025] Fig. 3 is a block diagram showing a configuration of a base station device 100 according to embodiment 2. The base station device 100 shown in Fig. 3 includes a network interface (hereinafter abbreviated as "network IF") 110, a processor 120, a memory 130, and a wireless communication unit 140.

[0026] The network IF 110 is connected to the core network by wire, and transmits and receives signals to and from devices such as the AMF 25 that constitute the core network.

[0027] The processor 120 is a control unit that includes, for example, a CPU (Central Processing Unit), an FPGA (Field Programmable Gate Array), or a DSP (Digital Signal Processor), and generally controls the entire base station device 100. In addition, when establishing communication with the terminal device 200 in a non-communication mode such as an RRC inactive mode, the processor 120 can generate a UE context for the terminal device 200 and notify the terminal device 200 of the identification information of the UE context, regardless of whether the terminal device 200 already holds the identification information of the UE context. That is, the processor 120 can generate a new UE context and notify the terminal device 200 of the identification information, regardless of whether the identification information of the UE context has already been notified to the terminal device 200 from another base station device 100.

[0028] The memory 130 includes, for example, a random access memory (RAM) or a read only memory (ROM), and stores information used in processing by the processor 120.

[0029] The wireless communication unit 140 executes wireless communication with the opposing terminal device 200. The wireless communication unit 140 transmits, for example, identification information of a UE context generated by the processor 120 to the terminal device 200. The wireless communication unit 140 also receives data transmitted from the terminal device 200. Note that the wireless communication unit 140 can execute predetermined communication with the terminal device 200 even when the opposing terminal device 200 is in a non-communication mode.

[0030] 4 is a block diagram showing a configuration of a terminal device 200 according to Embodiment 2. The terminal device 200 shown in FIG.

[0031] The wireless communication unit 210 performs wireless communication with the opposing base station device 100. The wireless communication unit 210 transmits and receives various signals for switching the communication mode and non-communication mode of the terminal device 200 with the base station device 100. For example, the wireless communication unit 210 receives identification information of a UE context notified from the base station device 100 when the terminal device 200 establishes communication with the base station device 100. Note that the wireless communication unit 210 can perform predetermined communication with the base station device 100 even when the terminal device 200 is in the non-communication mode.

[0032] The processor 220 is a control unit that includes, for example, a CPU, an FPGA, or a DSP, and controls the entire terminal device 200. The processor 220 also switches the mode of the terminal device 200 between, for example, a communication mode such as an RRC connected mode and a non-communication mode such as an RRC inactive mode. When establishing communication with the base station device 100 during the non-communication mode, the processor 220 can be notified of the identification information of the UE context generated by the base station device 100, regardless of whether the terminal device 200 already holds the identification information of the UE context. That is, the processor 220 holds the identification information of the UE context notified from the new base station device 100, regardless of whether the identification information of the UE context has already been notified from another base station device 100.

[0033] The memory 230 includes, for example, a RAM or a ROM, and stores information used in processing by the processor 220.

[0034] Next, an information management method in the wireless communication system configured as above will be described with reference to Fig. 5. In the following description, it is assumed that the wireless communication system has base station devices 100-1 and 100-2 having a configuration equivalent to base station device 100, and AMFs 25-1 and 25-2 having a configuration equivalent to AMF 25.

[0035] When the terminal device 200 establishes communication with the base station device 100-1, an access stratum (AS) message (hereinafter referred to as an "AS message") requesting a connection is transmitted from the terminal device 200 to the base station device 100-1 (step S101). Examples of this AS message include an RRC connection request and a connection resume request.

[0036] In response to this AS message, the base station device 100-1 transmits an AS message for predetermined settings to the terminal device 200 (step S102), and the terminal device 200 transmits an AS message notifying the base station device 100-1 of the completion of connection (step S103).

[0037] When a connection between the terminal device 200 and the base station device 100-1 is thus established, a Non-Access Stratum (NAS) message (hereinafter referred to as a "NAS message") for registration (e.g., location registration) is transmitted from the terminal device 200 to the AMF 25-1 that manages the base station device 100-1 via the base station device 100-1 (step S104). When the UE context of the terminal device 200 is registered by the AMF 25-1, a NAS message indicating that the registration has been accepted is transmitted from the AMF 25-1 to the terminal device 200 via the base station device 100-1 (step S105).

[0038] Furthermore, in the base station device 100-1, a UE context related to the terminal device 200 is generated. Then, temporary identification information including identification information of the terminal device 200 and identification information of the base station device 100-1 is generated as identification information of the UE context. As this temporary identification information, for example, the I-RNTI can be used. The I-RNTI is 40-bit identification information capable of simultaneously identifying the terminal device and the base station device. That is, the I-RNTI can be expressed as follows. I-RNTI = base station device identification information + terminal device identification information Since the I-RNTI is 40-bit identification information, if the number of bits allocated to the base station device identification information is increased, the number of identifiable base station devices increases but the number of identifiable terminal devices decreases. Conversely, if the number of bits allocated to the base station device identification information is decreased, the number of identifiable base station devices decreases but the number of identifiable terminal devices increases.

[0039] The generated UE context is held by the base station device 100-1, and identification information of the UE context is notified to the terminal device 200 by, for example, an AS message for releasing the connection (step S106). Upon receiving this notification, the terminal device 200 holds the identification information of the UE context and releases the connection with the base station device 100-1. At this time, the terminal device 200 may transition to, for example, an RRC inactive mode.

[0040] Then, for example, when the terminal device 200 moves and establishes communication with the base station device 100-2, the terminal device 200 transmits an AS message requesting a connection to the base station device 100-2 (step S107). In response to this AS message, the base station device 100-2 transmits an AS message for predetermined settings to the terminal device 200 (step S108), and the terminal device 200 transmits an AS message notifying the base station device 100-2 of the completion of the connection (step S109).

[0041] Here, the terminal device 200 according to the present embodiment already holds the identification information of the UE context notified from the base station device 100-1, but does not notify the base station device 100-2 of the UE context that it holds when newly establishing a connection with the base station device 100-2. That is, the terminal device 200 can establish a connection with the base station device 100-2 in the same procedure as that in which the connection with the base station device 100-1 was established, regardless of whether or not the terminal device 200 already holds the identification information of the UE context. Similarly, the terminal device 200 according to the present embodiment has already been registered (e.g., location registration) in the AMF 25-1, but does not notify the base station device 100-2 of information identifying the AMF 25-1. That is, the terminal device 200 can establish a connection with the base station device 100-2 in the same procedure as that in which the connection with the base station device 100-1 was established, regardless of whether or not the UE context has been registered in the AMF 25-1.

[0042] When a connection between the terminal device 200 and the base station device 100-2 is established in this manner, a NAS message for registration (e.g., location registration) is transmitted from the terminal device 200 to the AMF 25-2 that manages the base station device 100-2 via the base station device 100-2 (step S110). When the UE context of the terminal device 200 is registered by the AMF 25-2, a NAS message indicating that the registration has been accepted is transmitted from the AMF 25-2 to the terminal device 200 via the base station device 100-2 (step S111).

[0043] Furthermore, in the base station device 100-2, a UE context related to the terminal device 200 is generated. That is, the base station device 100-2 can generate temporary identification information including identification information of the terminal device 200 and identification information of the base station device 100-2 as identification information of the UE context, regardless of whether the terminal device 200 already holds identification information of the UE context. As this temporary identification information, for example, the I-RNTI can be used, like the identification information generated by the base station device 100-1.

[0044] The generated UE context is held by the base station device 100-2, and identification information of the UE context is notified to the terminal device 200 by, for example, an AS message for releasing the connection (step S112). Upon receiving this notification, the terminal device 200 holds the identification information of the UE context and releases the connection with the base station device 100-2. At this time, the terminal device 200 may transition to, for example, an RRC inactive mode.

[0045] In this way, when the terminal device 200 establishes a connection with the base station device 100-2, even if the terminal device 200 already holds the identification information of the UE context notified from the base station device 100-1, the terminal device 200 acquires and holds new identification information of the UE context from the base station device 100-2. Furthermore, even if the terminal device 200 already holds the identification information of the UE context notified from the base station device 100-1, the base station device 100-2 can generate a new UE context and notify the identification information. Furthermore, even if the UE context of the terminal device 200 has already been registered in the AMF 25-1, the AMF 25-2 can register a new UE context. As a result, even if the terminal device 200 in the RRC inactive mode moves from the communication range of the base station device 100-1 to the communication range of the base station device 100-2 and returns to the RRC connected mode, the transfer of the UE context between the base station devices or between the AMFs is not required. As a result, it is possible to suppress a communication delay when the terminal device 200 returns to the RRC connected mode, and to reduce a processing load due to signaling related to the transfer of the UE context. In other words, it is possible to improve adaptability to various situations.

[0046] Note that the generation of a UE context by the base station devices 100-1 and 100-2, or the registration of a UE context by the AMFs 25-1 and 25-2 is not executed only when the terminal device 200 moves. For example, even when the terminal device 200 is stationary, a UE context may be generated by each of the multiple base station devices 100-1 and 100-2 to which the terminal device 200 can be connected, or a UE context may be registered in each of the multiple AMFs 25-1 and 25-2. That is, the processes of steps S101 to S106 and the processes of steps S107 to S112 shown in FIG. 5 may be executed in parallel at the same time.

[0047] In the above description, the UE context is registered by the AMFs 25-1 and 25-2, but the context corresponding to this UE context is also registered in the SMF 15. That is, for example, as shown in FIG. 6, when a registration request is transmitted from the terminal device 200 to the AMF 25-1 via the base station device 100-1, an AUSF (Authentication Server Function) and a UDM (Unified Data Management) are selected by the AMF 25-1. After that, the context is updated from the AMF 25-1 to the SMF 15.

[0048] Next, a paging process in a case where the base station devices 100-1 and 100-2 and the AMFs 25-1 and 25-2 each hold a UE context related to the terminal device 200 will be described with reference to a sequence diagram shown in FIG.

[0049] When DL data addressed to the terminal device 200 occurs, the SMF 15 transmits a message notifying the occurrence of DL data to the AMFs 25-1 and 25-2 in which the UE context of the terminal device 200 is registered in order to call the terminal device 200 (step S201). That is, in this embodiment, since the UE context of the terminal device 200 is registered in both the AMFs 25-1 and 25-2, the SMF 15 notifies the AMFs 25-1 and 25-2 of the occurrence of DL data addressed to the terminal device 200.

[0050] The AMF 25-1 that has received the notification executes paging to call the terminal device 200 via the base station device 100-1 (step S202). Similarly, the AMF 25-2 that has received the notification executes paging to call the terminal device 200 via the base station device 100-2 (step S203). In this way, since the UE context related to the terminal device 200 is held in each of the AMFs 25-1 and 25-2 and the base station devices 100-1 and 100-2, it is possible to call the terminal device 200 via a plurality of routes, and it is possible to improve the reliability of paging. For example, it is expected to improve characteristics such as a higher possibility that the terminal device 200 can receive paging and a faster response to paging.

[0051] The terminal device 200 that has received the page starts a service request procedure (step S204) and selects a path that passes through one of the base station devices 100-1 and 100-2 that have received the page. That is, since the paging message is received from multiple paths that pass through the base station devices 100-1 and 100-2, the terminal device 200 selects one of the paths. Here, the description will be continued assuming that the path that passes through the base station device 100-1 is selected.

[0052] When a path passing through the base station device 100-1 is selected in the service request procedure, DL data is transmitted from, for example, a UPF (User Plane Function) of the core network through the selected path (step S205). Note that uplink data may be transmitted and received through the selected path passing through the base station device 100-1. Furthermore, since the terminal device 200 has selected the path passing through the base station device 100-1, the terminal device 200 may transmit a NAS message requesting deregistration to the AMF 25-2 through the unselected path (step S206). In response to this, the AMF 25-2 deletes the registration of the terminal device 200 and also deletes the UE context. As a result, a U-plane data path passing through the base station device 100-1 can be uniquely established between the terminal device 200 and the AMF 25-1.

[0053] In this way, since the AMFs 25-1 and 25-2 each hold a UE context related to the terminal device 200, paging can be performed across the tracking areas of both the AMFs 25-1 and 25-2, and the reliability of paging can be improved. Note that the terminal device 200 monitors paging for multiple paths passing through the base station devices 100-1 and 100-2, so the power consumption of the terminal device 200 increases. For this reason, the terminal device 200 may compare the reception levels from the base station devices 100-1 and 100-2, and when the difference in the reception levels is equal to or greater than a predetermined threshold, monitor paging only for the path passing through the base station device with the higher reception level. In this way, the terminal device 200 can monitor paging from a closer base station device and can reduce the power consumption related to monitoring paging.

[0054] As described above, according to the present embodiment, when a terminal device establishes a connection with a base station device, even if the terminal device already holds identification information of a UE context notified from another base station device, the terminal device acquires and holds identification information of the UE context from the newly connected base station device, and the AMF registers a new UE context even if the UE context of the terminal device has already been registered in another AMF, and the base station device can notify identification information of the new UE context even if the terminal device already holds identification information of a UE context notified from another base station device. Therefore, even if the base station device that is the communication partner of the terminal device is changed or the terminal device moves across tracking areas managed by different AMFs, the transfer of the UE context does not occur. Therefore, it is possible to suppress communication delays of the terminal device and reduce the processing load due to signaling related to the transfer of the UE context. In other words, it is possible to improve adaptability to various situations.

[0055] (Embodiment 3) In the above-mentioned second embodiment, when the terminal device 200 establishes a connection with the base station devices 100-1 and 100-2, it is registered (e.g., location registered) in the AMFs 25-1 and 25-2. However, when the base station devices 100-1 and 100-2 are connected under one AMF 25, it is possible to omit the registration in the AMF 25. Therefore, in the third embodiment, an operation in the case where the base station devices 100-1 and 100-2 are connected to one AMF 25 will be described.

[0056] The configuration of the wireless communication system according to the third embodiment and the configurations of the base station device 100 and the terminal device 200 are the same as those of the second embodiment (FIGS. 2 to 4), and therefore description thereof will be omitted. FIG. 8 is a sequence diagram showing an information management method in the wireless communication system according to the third embodiment. In FIG. 8, the same parts as those in FIG. 5 are given the same reference numerals. In the following description, it is assumed that the wireless communication system has base station devices 100-1 and 100-2 having the same configuration as the base station device 100, and that both base station devices 100-1 and 100-2 are connected under AMF 25.

[0057] When the terminal device 200 establishes communication with the base station device 100-1, an AS message requesting a connection is transmitted from the terminal device 200 to the base station device 100-1 (step S101). Examples of this AS message include an RRC connection request and a connection resume request.

[0058] In response to this AS message, the base station device 100-1 transmits an AS message for predetermined settings to the terminal device 200 (step S102), and the terminal device 200 transmits an AS message notifying the base station device 100-1 of the completion of connection (step S103).

[0059] When a connection between the terminal device 200 and the base station device 100-1 is established in this manner, a NAS message for registration (e.g., location registration) is transmitted from the terminal device 200 to the AMF 25 that manages the base station device 100-1 via the base station device 100-1 (step S104). When the terminal device 200 is registered by the AMF 25, a NAS message indicating that the registration has been accepted is transmitted from the AMF 25 to the terminal device 200 via the base station device 100-1 (step S105). As a result, the UE context is registered (established) between the AMF 25 and the terminal device 200.

[0060] Furthermore, in the base station device 100-1, a UE context related to the terminal device 200 is generated. Then, temporary identification information including identification information of the terminal device 200 and identification information of the base station device 100-1 is generated as identification information of the UE context. As this temporary identification information, for example, the I-RNTI can be used. The I-RNTI is 40-bit identification information capable of simultaneously identifying the terminal device and the base station device.

[0061] The generated UE context is held by the base station device 100-1, and identification information of the UE context is notified to the terminal device 200 by, for example, an AS message for releasing the connection (step S106). Upon receiving this notification, the terminal device 200 holds the identification information of the UE context and releases the connection with the base station device 100-1. At this time, the terminal device 200 may transition to, for example, an RRC inactive mode.

[0062] Then, for example, when the terminal device 200 moves and establishes communication with the base station device 100-2, the terminal device 200 transmits an AS message requesting a connection to the base station device 100-2 (step S107). In response to this AS message, the base station device 100-2 transmits an AS message for predetermined settings to the terminal device 200 (step S108), and the terminal device 200 transmits an AS message notifying the base station device 100-2 of the completion of the connection (step S109).

[0063] Here, the base station device 100-2 is connected under the same AMF 25 as the base station device 100-1 that has already notified the terminal device 200 of the identification information of the UE context. Therefore, when the terminal device 200 establishes a connection with the base station device 100-2, the registration with the AMF 25 is omitted. Therefore, no NAS message is transmitted and received between the terminal device 200 and the AMF 25, and the UE context related to the terminal device 200 is generated in the base station device 100-2. That is, the base station device 100-2 can generate temporary identification information including the identification information of the terminal device 200 and the identification information of the base station device 100-2 as the identification information of the UE context, regardless of whether the terminal device 200 already holds the identification information of the UE context. As the temporary identification information, for example, the I-RNTI can be used, like the identification information generated by the base station device 100-1.

[0064] The generated UE context is held by the base station device 100-2, and identification information of the UE context is notified to the terminal device 200 by, for example, an AS message for releasing the connection (step S112). Upon receiving this notification, the terminal device 200 holds the identification information of the UE context and releases the connection with the base station device 100-2. At this time, the terminal device 200 may transition to, for example, an RRC inactive mode.

[0065] In this way, when the terminal device 200 establishes a connection with the base station device 100-2, even if the terminal device 200 already holds the identification information of the UE context notified from the base station device 100-1, the terminal device 200 newly acquires and holds the identification information of the UE context from the base station device 100-2. Also, even if the terminal device 200 already holds the identification information of the UE context notified from the base station device 100-1, the base station device 100-2 generates a new UE context and notifies the identification information. As a result, even if the terminal device 200 in the RRC inactive mode moves from the communication range of the base station device 100-1 to the communication range of the base station device 100-2 and returns to the RRC connected mode, the transfer of the UE context between the base station devices is not required. As a result, it is possible to suppress a delay in communication when the terminal device 200 returns to the RRC connected mode, and it is possible to reduce the processing load due to the signaling related to the transfer of the UE context. In other words, it is possible to improve adaptability to various situations.

[0066] Furthermore, when the base station devices 100-1 and 100-2 are connected under one AMF 25, the terminal device 200 registers with the AMF 25 via the base station device 100-1, and omits registration with the AMF 25 when establishing a connection with the base station device 100-2. This makes it possible to omit unnecessary registrations and reduce the load on the wireless communication system.

[0067] Fig. 9 is a diagram showing a specific example of data communication when the terminal device 200 moves. As shown in Fig. 9, the terminal device 200 establishes a connection with, for example, the base station device 100-1, and is registered in the AMF 25, whereby a UE context related to the terminal device 200 is generated. In addition, the terminal device 200 is notified of identification information of the UE context from the base station device 100-1. Then, it is assumed that the terminal device 200 transitions to, for example, an RRC inactive mode within the communication range of the base station device 100-1, and moves into the communication range of the base station device 100-2 during the RRC inactive mode.

[0068] For example, when the terminal device 200 returns to the RRC connected mode within the communication range of the base station device 100-2, the terminal device 200 establishes a connection with the base station device 100-2. At this time, since the base station device 100-2 is connected under the same AMF 25 as the base station device 100-1, the terminal device 200 omits registration with the AMF 25 and receives a notification of the identification information of the UE context from the base station device 100-2. That is, the base station device 100-2 generates new identification information of the UE context and notifies the terminal device 200 of the identification information without transferring the UE context between the base station device 100-1 to which the terminal device 200 was most recently connected. Then, communication is started between the terminal device 200 and the base station device 100-2. Therefore, communication between the terminal device 200 and the base station device 100-2 is quickly started without transferring the UE context between the base station devices, and the processing load due to the signaling related to the transfer of the UE context can be reduced.

[0069] Furthermore, when establishing a connection with the base station device 100-2, registration of the terminal device 200 to the AMF 25 is omitted, so that unnecessary registration does not occur and the load on the wireless communication system can be reduced.

[0070] As described above, according to the present embodiment, when a terminal device establishes a connection with a base station device, even if the terminal device already holds identification information of a UE context notified from another base station device, the terminal device acquires and holds identification information of the UE context from the newly connected base station device, and the base station device can notify identification information of a new UE context even if the terminal device already holds identification information of a UE context notified from another base station device. Therefore, even if the base station device that is the communication partner of the terminal device is changed, the transfer of the UE context does not occur. Therefore, it is possible to suppress a delay in communication of the terminal device and to reduce a processing load due to signaling related to the transfer of the UE context. In other words, it is possible to improve adaptability to various situations.

[0071] In addition, even if the base station device to which the terminal device communicates is changed, if the upper AMF is not changed, the terminal device omits registration to the AMF. Therefore, unnecessary registration does not occur, and the load on the wireless communication system can be reduced.

[0072] In the above-mentioned embodiments, the downlink communication has been described by taking as an example the paging process in the case where the base station device 100 and the AMF 25 each hold the UE context related to the terminal device 200, but it goes without saying that the uplink communication may be performed. When the uplink communication is performed, the communication is started from a request to establish an RRC connection instead of the paging process. [Explanation of symbols]

[0073] 110 Network Interface 120, 220 processors 130, 230 Memory 140, 210 Wireless communication section

Claims

1. A control unit capable of controlling, when establishing communication with another wireless communication device in a non-communication mode, to generate first identification information among identification information capable of simultaneously identifying the device itself and the other wireless communication device, regardless of whether the other wireless communication device holds second identification information among the identification information, and to notify the other wireless communication device of the generated first identification information. A wireless communication device comprising:

2. The control unit is notifying the other wireless communication device of the first identification information together with a message for releasing the connection with the other wireless communication device; 2. The wireless communication device according to claim 1.

3. The identification information is It is an I-RNTI (Inactive-Radio Network Temporary Identifier) ​​that can simultaneously identify a pair of wireless communication devices that wirelessly communicate with each other.

2. The wireless communication device according to claim 1.

4. A control unit capable of controlling, when establishing communication with another wireless communication device during a non-communication mode, to notify from the other wireless communication device of first identification information among identification information capable of simultaneously identifying the own device and the other wireless communication device, the first identification information being generated by the other wireless communication device, regardless of whether the own device holds second identification information among the identification information. A wireless communication device comprising:

5. The control unit is The first identification information is notified from the other wireless communication device together with a message for releasing the connection with the other wireless communication device.

5. The wireless communication device according to claim 4.

6. The identification information is It is an I-RNTI (Inactive-Radio Network Temporary Identifier) ​​that can simultaneously identify a pair of wireless communication devices that wirelessly communicate with each other.

5. The wireless communication device according to claim 4.

7. A wireless communication system having a first wireless communication device and a second wireless communication device, The first wireless communication device is a first control unit that can control, when establishing communication with the second wireless communication device in a non-communication mode, to generate first identification information among identification information capable of simultaneously identifying the device and the second wireless communication device, regardless of whether the second wireless communication device holds second identification information among the identification information, and to notify the second wireless communication device of the generated first identification information; The second wireless communication device is and a second control unit that can control, when establishing communication with the first wireless communication device during a non-communication mode, to transmit the first identification information generated by the first wireless communication device from the first wireless communication device regardless of whether the device holds the second identification information.

1. A wireless communication system comprising:

8. 1. An information management method executed by a wireless communication device, comprising: When establishing communication with another wireless communication device in a non-communication mode, generating first identification information among identification information capable of simultaneously identifying the wireless communication device and the other wireless communication device, regardless of whether the other wireless communication device holds second identification information among the identification information; Notifying the other wireless communication device of the generated first identification information.

23. An information management method comprising the steps of:

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