Communication terminal, base station, terminal program, base station program, communication system, and communication method

Abstract

This communication terminal comprises a terminal communication unit that performs a wireless communication with a base station, and a terminal control unit that controls the terminal communication unit. The terminal control unit: causes the terminal communication unit to transmit a first message of the wireless communication to the base station without including, in the first message, specific terminal information indicating that the communication terminal is a specific communication terminal the use of which may be limited by the base station; receives, from the base station via the terminal communication unit, a second message serving as a response to the first message; and causes the terminal communication unit to transmit a subsequent message including a third message serving as a response to the second message to the base station, with the specific terminal information included in the subsequent message.

Description

[Technical Field]

[0001] The present disclosure relates to a communication terminal, a base station, a terminal program, a base station program, a communication system, and a communication method. [Background technology]

[0002] Currently, the 3GPP (registered trademark) (Third Generation Partnership Project) is considering the use of various communication terminals such as IoT (Internet of Things) devices. For this reason, RedC, a standard that limits part of the NR (New Radio) functions of certain communication terminals, is being developed. AP is being considered.

[0003] One example of a restriction based on RedCap (Reduced Capability) is to limit the available bandwidth of a specific communication terminal. RedCap is also being considered to limit the number of antennas that a base station with MIMO (Multi-Input Multi-Output) functionality can assign to a specific communication terminal. RedCap is also being considered to limit the communication speed of a specific communication terminal.

[0004] The specific communication terminal is called, for example, RedCap UE (User Equipment). RedCap UE is expected to be connected to many UEs such as IoT devices, and therefore, in the event of an emergency, it is desirable that the use of its communication functions be restricted.

[0005] In addition, the 3GPP (Third Generation Partnership Project) is currently discussing an early indication function. The early indication function is a function that is used to transmit messages in the Random Access Channel (RACH) process that is the first step that a communication terminal performs to communicate with a base station. This is a function that notifies the network (NW) that it is a specific communication terminal by using a message.

[0006] Therefore, the communication terminal transmits to the base station a message including specific terminal information, for example, RedCap information, that indicates to the base station that the communication terminal is a specific communication terminal. This allows the base station to recognize that the communication terminal is a specific communication terminal, for example, a RedCap UE. As a result, the base station executes, for example, the processes described in the following (1) and (2).

[0007] (1) Perform configuration to restrict the communication functions of RedCap UE in the network.

[0008] (2) When an emergency such as a disaster occurs, in order to reduce the load on the network, the system executes a process to quickly disconnect communication with the RedCap UE that has requested connection to the base station.

[0009] The reason for performing the above process (2) is that in the event of an emergency, communication between a UE with a high level of urgency and the base station may be disrupted by a RedCap UE connected to a large number of UEs. [Prior art documents] [Patent documents]

[0010] [Patent Document 1] International Publication No. WO2021 / 161622A1 Summary of the Invention [Problem to be solved by the invention]

[0011] Currently, when an emergency occurs due to a disaster such as an earthquake, the base station uniformly denies connection to any RedCap UE. As a result, even special-purpose RedCap UEs that are highly required to connect to the base station in the event of an emergency are unable to connect to the base station. Examples of special-purpose RedCap UEs include mobile phones used by rescuers who are carrying out relief efforts for disaster victims, or wearable devices that transmit vital signs of injured or sick people.

[0012] In other words, when normal RedCap UE communication is restricted due to the occurrence of an emergency, the communication functions of the special-purpose RedCap UE described above cannot be used, even for safety confirmation or life support.

[0013] The present disclosure has been made in consideration of the above-mentioned problems. An object of the present disclosure is to enable a specific communication terminal to use its communication function even in an emergency. This specification discloses a communication terminal, a base station, a terminal program, and a base station program that can achieve such an object, as well as a communication system including them and a communication method using them. [Means for solving the problem]

[0014] The communication terminal of the present disclosure is a communication terminal comprising a terminal communication unit that performs wireless communication with a base station and a terminal control unit that controls the terminal communication unit, wherein the terminal control unit causes the terminal communication unit to transmit a first message of the wireless communication to the base station without including specific terminal information indicating that the communication terminal is a specific communication terminal that may be restricted in use by the base station, receives a second message in response to the first message from the base station via the terminal communication unit, and causes the terminal communication unit to include the specific terminal information in subsequent messages from a third message onwards in response to the second message and transmit the subsequent messages to the base station.

[0015] The base station of the present disclosure is a base station comprising a base communication unit that performs wireless communication with a communication terminal, and a base control unit that controls the base communication unit, wherein the base control unit receives a first message of the wireless communication from the communication terminal via the base communication unit, and if the first message does not include specific terminal information indicating that the communication terminal is a specific communication terminal that may be restricted in use by the base station, causes the base communication unit to send a second message to the communication terminal in response to the first message, receives subsequent messages from the communication terminal, including a third message in response to the second message, and if the subsequent messages include the specific terminal information, causes the communication terminal to use the communication functions of the specific communication terminal.

[0016] The terminal program of the present disclosure is a computer-readable terminal program for causing a computer to operate as a terminal control unit that controls a terminal communication unit in a communication terminal that performs wireless communication with a base station, wherein the terminal control unit causes the terminal communication unit to send a first message of the wireless communication to the base station without including specific terminal information indicating that the communication terminal is a specific communication terminal that may be restricted in use by the base station, receives a second message in response to the first message from the base station via the terminal communication unit, includes the specific terminal information in subsequent messages from a third message onwards in response to the second message, and causes the terminal communication unit to send the subsequent messages to the base station.

[0017] The base program disclosed herein is a computer-readable base program for causing a computer to operate as a base control unit that controls a base communication unit that performs wireless communication with a communication terminal in a base station, wherein the base control unit receives a first message of the wireless communication from the communication terminal via the base communication unit, and if the first message does not include specific terminal information indicating that the communication terminal is a specific communication terminal that may be restricted in use by the base station, causes the base communication unit to send a second message to the communication terminal in response to the first message, receives subsequent messages from the communication terminal, including a third message in response to the second message, and if the subsequent messages include the specific terminal information, causes the communication terminal to use the communication function of the specific communication terminal.

[0018] The communication system of the present disclosure is a communication system including a communication terminal and a base station that performs wireless communication with the communication terminal, wherein the communication terminal transmits a first message of the wireless communication to the base station without including specific terminal information indicating that the communication terminal is a specific communication terminal that may be restricted in use by the base station, the base station receives the first message from the communication terminal and transmits a second message to the communication terminal in response to the first message, the communication terminal receives the second message from the base station and includes the specific terminal information in subsequent messages, such as a third message and subsequent messages in response to the second message, and transmits the subsequent messages to the base station, and the base station receives the subsequent messages from the communication terminal and, if the specific terminal information is included in the subsequent messages, allows the communication terminal to use the communication functions of the specific communication terminal.

[0019] The communication method disclosed herein is a communication method between a communication terminal and a base station that performs wireless communication with the communication terminal, wherein the communication terminal transmits a first message of the wireless communication to the base station without including specific terminal information indicating that the communication terminal is a specific communication terminal that may be restricted in use by the base station, the base station receives the first message from the communication terminal and transmits a second message to the communication terminal in response to the first message, the communication terminal receives the second message from the base station and includes the specific terminal information in subsequent messages, such as a third message and subsequent messages in response to the second message, and transmits the subsequent messages to the base station, and the base station receives the subsequent messages from the communication terminal and, if the specific terminal information is included in the subsequent messages, allows the communication terminal to use the communication functions of the specific communication terminal. [Brief explanation of the drawings]

[0020] [Figure 1] 1 is a schematic diagram illustrating a communication system and a network according to an embodiment; [Figure 2] 2 is a block diagram showing the internal configuration of each of a communication terminal and a base station that constitute the communication system of the embodiment. FIG. [Figure 3] 10 is a sequence diagram for explaining a mode of message transmission and reception in an emergency between a communication terminal and a base station that constitute a communication system according to an embodiment. FIG. [Figure 4] 1 is a schematic diagram for explaining a communication terminal that can communicate with a base station in an emergency state in a communication system according to an embodiment and a communication terminal that cannot communicate with a base station in an emergency state. [Figure 5] FIG. 10 is a sequence diagram for explaining a mode of message transmission and reception in an emergency between a communication terminal and a base station that constitute a communication system of a comparative example. [Figure 6] 10 is a schematic diagram for explaining a communication terminal that cannot communicate with a base station in an emergency state in a communication system of a comparative example. FIG. [Figure 7]10 is a flowchart illustrating a process executed by a terminal control unit of a communication terminal in the communication system according to the embodiment. [Figure 8] 10 is a flowchart illustrating a process executed by a base station control unit of a base station in the communication system according to the embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0021] Hereinafter, a communication terminal, a base station, a terminal program, a base station program, a communication system including them, and a communication method using them according to embodiments of the present disclosure will be described with reference to the drawings. Note that in the drawings, the same or equivalent elements are designated by the same reference numerals, and redundant descriptions of the same or equivalent elements will not be repeated.

[0022] FIG. 1 is a schematic diagram showing a communication system CS and a network NW according to an embodiment.

[0023] As shown in Fig. 1, the base stations gNB constituting the communication system CS are connected to each other via a network NW so as to be able to communicate wirelessly or wired. The communication system CS includes a communication terminal UE and a base station gNB. The communication terminal UE and the base station gNB are connected to each other so as to be able to communicate wirelessly. In this embodiment, the network NW is a telecommunications network called the Internet, but may be another telecommunications network.

[0024] The communication terminal UE is a RedCap UE, which is an example of a specific communication terminal that complies with the standards of a 5G (Fifth Generation) mobile communication system. However, the communication terminal UE may also be one that complies with standards other than the standards of a 5G mobile communication system, such as standards of a 3G, 4G, or 6G mobile communication system. The communication terminal UE is, for example, a mobile terminal such as a smartphone. However, the communication terminal UE may be any communication device that can communicate with a base station gNB in ​​a communication system CS, such as one called IoT (Internet of Things). The communication terminal UE may also be any RedCap UE that can communicate with a base station gNB, such as a surveillance camera, a sensor, or a wearable device, whose use can be restricted by the base station gNB in ​​an emergency.

[0025] A base station gNB (next generation Node B) is a base station that complies with the standards of a 5G mobile communication system. The base station gNB is a base station newly designed for the 5G communication system and has functions different from those of the base station (eNB: evolved Node B) used in the 4G communication system EPS. However, the base station gNB may also comply with standards other than the 5G mobile communication system, such as 3G, 4G, or 6G mobile communication systems.

[0026] FIG. 2 is a block diagram showing the internal configuration of each of the communication terminal UE and the base station gNB that constitute the communication system CS according to the embodiment.

[0027] As shown in FIG. 2, the communication terminal UE includes a terminal communication unit TC, a terminal operation unit TO, a terminal storage unit TM, and a terminal control unit TP.

[0028] The terminal communication unit TC receives a message transmitted from the base station gNB and transmits the received message to the terminal control unit TP. The terminal communication unit TC includes at least one antenna.

[0029] The terminal operation unit TO has a function as a switch operated by a user of the communication terminal UE. The terminal operation unit TO transmits a signal based on the operation to the terminal control unit TP. The terminal operation unit TO may be any device, such as a physical push button switch or an icon displayed on a touch pad, as long as it can transmit a signal indicating that the current state is an emergency to the terminal control unit TP when operated by the user.

[0030] The terminal storage unit TM stores terminal programs that cause the terminal control unit TC to execute various processes. The terminal storage unit TM is a non-transitory tangible storage medium. The terminal storage unit TM may be any type of memory, such as a RAM (Random Access Memory) or a ROM (Read Only Memory).

[0031] The terminal control unit TP executes the following processes based on the terminal program stored in the terminal storage unit TM. The terminal control unit TP executes a process to receive a message transmitted from the base station gNB via the terminal communication unit TC. The terminal control unit TP executes a process to generate a response message to the received message. The terminal control unit TP executes a process to make the terminal communication unit TC transmit the response message to the communication terminal UE. The terminal control unit TP is built into hardware called a computer and is configured by a processor that can read the terminal program from a computer.

[0032] In this embodiment, the communications terminal UE is provided with a terminal operation unit TO that is operated by a user. When the user performs a predetermined operation, the terminal operation unit TO transmits state information indicating whether the current state is a normal state or an emergency state to the terminal control unit TC. However, the communications terminal UE does not have to be provided with the terminal operation unit TO. In this case, the terminal control unit TP receives state information indicating whether the current state is a normal state or an emergency state, for example, information notifying an emergency state such as a disaster issued by the government, from outside the terminal device UE via the terminal communication unit TC. In either case, the terminal control unit TP executes processing to determine whether the current state is a normal state or an emergency state (see S101 in FIG. 7). However, if the communications terminal UE is configured to be always used in an emergency state mode, that is, if it is never used in a normal state mode, the terminal control unit TP does not need to perform processing to determine whether the current state is a normal state or an emergency state.

[0033] An emergency state is a state in which, for example, a disaster such as an earthquake, fire, tsunami, or explosion occurs, and it is expected that an extremely large number of communication terminals UE attempt to communicate via a single base station gNB. Another emergency state is a state in which, for example, a fireworks display, a concert, or other event attracting many people is held, and it is expected that an extremely large number of communication terminals UE attempt to communicate via a single base station gNB. In such an emergency state, if all communication terminals UE attempting to communicate with other communication terminals UE via a single base station gNB are forced to use their communication functions, communication failures or the like may occur in the network NW. Therefore, in an emergency state, it is preferable for the base station gNB to not allow a specific communication terminal, such as a RedCap UE, to use its communication function as that specific communication terminal. Specifically, it is preferable for the base station gNB to refuse connection of the specific communication terminal to the base station gNB.

[0034] However, as described above, it is preferable that some specific communication terminals be allowed to use the functions of the specific communication terminal via the network NW even in an emergency state. Therefore, the communication terminal UE, which is the specific communication terminal of this embodiment, is configured to be able to use the functions of the specific communication terminal even in an emergency state. Furthermore, the base station gNB of this embodiment is configured to be able to allow the communication terminal UE, which is the specific communication terminal, to use the functions of the specific communication terminal even in an emergency state.

[0035] On the other hand, the normal state is a state that is not the above-mentioned emergency state. Therefore, the normal state is a state in which the base station gNB makes the communication terminal UE use the communication functions of the communication terminal UE, regardless of whether the communication terminal UE is a normal communication terminal that is not a specific communication terminal or a specific communication terminal. More specifically, in the normal state, if the communication terminal UE is a normal communication terminal that is not a specific communication terminal, the base station gNB is configured to make the communication terminal UE use the communication functions of a normal communication terminal. Also, if the communication terminal UE is a specific communication terminal, the base station gNB is configured to make the communication terminal UE use the communication functions of a specific communication terminal.

[0036] The base station gNB includes a base communication unit BC, a base memory unit BM, a base operation unit BO, and a base control unit BP.

[0037] The base communication unit BC receives messages transmitted from the communication terminal UE and transmits the received messages to the base control unit BP. The base communication unit BC includes at least one antenna.

[0038] The base station operation unit BO functions as a switch operated by a user who manages the base station gNB. The base station operation unit BO transmits a signal based on the operation to the base station control unit BP. The base station operation unit BO may be any device, such as a physical push button switch or an icon displayed on a touchpad, that can transmit a predetermined signal, for example, a signal indicating that the current status is an emergency, to the base station control unit BP when operated by the user.

[0039] The base memory unit BM stores base programs that cause the base control unit BP to execute various processes. The base memory unit BM is a non-transitory tangible storage medium. The base memory unit BM may be any type of memory, such as RAM or ROM.

[0040] The base control unit BP executes the following processes based on the base program stored in the base memory unit BM. The base control unit BP executes a process to receive a message transmitted from the communication terminal UE via the base communication unit BC. The base control unit BP executes a process to generate a response message to the received message. The base control unit BP executes a process to make the base communication unit BC transmit the response message to the communication terminal UE. The base control unit BP is built into hardware called a computer, and is composed of a processor that can read the base program from a computer.

[0041] In this embodiment, the base station gNB is equipped with a base operation unit BO that is operated by a user. When the user performs a predetermined operation, the base operation unit BO transmits status information indicating whether the current status is a normal status or an emergency status to the base control unit BP. However, the base station gNB does not necessarily have to be equipped with a base operation unit BO. In this case, the base control unit BP receives status information indicating whether the current status is a normal status or an emergency status, for example, information issued by the government informing of an emergency status such as a disaster, from outside the base station gNB via a base communication unit BC. In either case, the base control unit BP determines whether the current status is a normal status or an emergency status (see S202 in FIG. 8).

[0042] FIG. 3 is a sequence diagram for explaining a mode of message transmission and reception in an emergency state between a communication terminal UE and a base station gNB that constitute a communication system CS of an embodiment.

[0043] In the communication system CS of this embodiment, in step S1, the communication terminal UE transmits a first message Msg-1 to the base station gNB. At this time, the communication terminal UE does not include specific terminal information in the first message Msg-1 of wireless communication. This specific terminal information is information indicating that the communication terminal UE is a specific communication terminal whose use may be restricted by the base station gNB. In addition, the specific terminal information is also information indicating that some of the communication functions of the specific communication terminal are restricted compared to the communication functions of a normal communication terminal.

[0044] The specific terminal information may indicate, for example, that the specific communication terminal uses a bandwidth equal to or less than a predetermined value. However, the specific terminal information may also indicate that the communication speed of the specific communication terminal is equal to or less than a predetermined value. Furthermore, the specific terminal information may also indicate that the number of antennas allocated by the base station for the specific communication terminal is less than the number of antennas allocated to normal communication terminals.

[0045] In this embodiment, the specific communication terminal is a RedCap UE defined in the 5G communication standard. The bandwidth equal to or less than the predetermined value is the RedCap bandwidth defined in the 5G communication standard. The specific terminal information is RedCap information defined in the 5G communication standard.

[0046] In step S2, the base station gNB receives a first message Msg-1 from the communication terminal UE. In step S3, the base station gNB performs configuration on the communication terminal UE to allow it to use the communication functions of a normal communication terminal in the network NW, i.e., a normal UE. A normal communication terminal is a communication terminal that is not a specific communication terminal. In step S4, the base station gNB transmits a second message Msg-2 to the communication terminal UE as a response to the first message Msg-1.

[0047] In step S5, the communication terminal UE receives a second message Msg-2 from the base station gNB. In step S6, the communication terminal UE includes the above-mentioned specific terminal information in a third message Msg-3 as a response to the second message Msg-2, and transmits the third message Msg-3 to the base station gNB. However, the communication terminal UE may also include the above-mentioned specific terminal information in a subsequent message after the third message Msg-3, for example, a fifth message Msg-5.

[0048] Next, in step S7, the base station gNB receives a third message Msg-3 including specific terminal information from the communication terminal UE. In step S8, if the specific terminal information is included in the third message Msg-3, the base station gNB configures the communication terminal UE to use the communication functions as a specific communication terminal in the network NW, even if the current state is an emergency state. However, if the specific terminal information is included in a subsequent message after the third message, for example, a fifth message Msg-5, the base station gNB may configure the communication terminal UE to use the communication functions as a specific communication terminal in the network NW. In step S9, the base station gNB transmits a fourth message Msg-4 to the communication terminal UE as a response to the third message Msg-3. In step S10, the communication terminal UE receives the fourth message Msg-4.

[0049] In addition, the base station gNB performs the same processes as steps S7 to S9 even when specific terminal information is included in a subsequent message after the third message Msg-3, for example, a fifth message Msg-5 (not shown).

[0050] FIG. 4 is a schematic diagram for explaining a communication terminal UE that can communicate with the base station gNB in ​​an emergency state of the communication system CS of the embodiment and a communication terminal UE that cannot communicate with the base station gNB in ​​the emergency state.

[0051] As can be seen from FIG. 4, communication terminals UE1, UE2, UE3, and UES connect to a base station gNB. The communication terminal UE1 has a surveillance camera function, and the communication terminal UE2 is a wearable device with functions similar to those of a normal smartphone. The communication terminal UE3 is a sensor in a factory or an IoT device. The communication terminal UES is a wearable device with a function to acquire a person's medical vital sign information and transmit it to the base station gNB. The communication terminals UE1, UE2, UE3, and UES are all RedCap UEs. The communication terminals UE1, UE2, and UE3 are communication terminals that are unlikely to need to connect to the base station gNB in ​​an emergency. Therefore, the communication terminals UE1, UE2, and UE3 are configured to include RedCap information in the first message Msg-1. On the other hand, the communication terminal UES is a communication terminal that transmits medical vital sign information, and therefore is a communication terminal that is preferably able to connect to the base station gNB even in an emergency. Therefore, as explained using FIG. 3, the communications terminal UES is configured to include RedCap information in the third message Msg-3, not in the first message Msg-1.

[0052] As can be seen from Figure 4, for example, a communication terminal UES that transmits medical vital information can communicate with the base station gNB using the communication method described with reference to Figure 3, even if the use of RedCap UE is restricted in an emergency state. That is, the communication terminal UES can communicate with other communication terminals via the network NW using the communication function as RedCap UE. On the other hand, in an emergency state, since the use of RedCap UE is restricted, each of the communication terminals UE1, UE2, and UE3 cannot communicate with the base station gNB. That is, each of the communication terminals UE1, UE2, and UE3 cannot communicate with other communication terminals via the network NW using the communication function as RedCap UE.

[0053] FIG. 5 is a sequence diagram for explaining a mode of message transmission and reception in an emergency state between a communication terminal UE and a base station gNB that constitute a communication system CS of a comparative example.

[0054] As can be seen from Fig. 5, in step S11, the communications terminal UE includes specific terminal information, for example, RedCap information, in the first message Msg-1 and transmits the first message Msg-1 to the base station gNB. In step S12, the base station gNB receives the first message Msg-1. In step S13, if the current state is a normal state, the base station gNB performs configuration on the communications terminal UE, which is a RedCap UE, to allow the communications terminal UE to use the communication functions as a RedCap UE. Thereafter, in step S14, the base station gNB transmits a second message Msg-2 to the communications terminal UE.

[0055] Therefore, according to the communication system of the comparative example shown in Fig. 5, the communication terminal UE as RedCap UE can receive the second message Msg-2 in step S15 when the current state is a normal state. Furthermore, the base station gNB receives the third message Msg-3 in step S17, and transmits the fourth message Msg-4 in step S19. Therefore, the communication terminal UE as RedCap UE can transmit the third message Msg-3 to the base station gNB in ​​step S16, and receive the fourth message Msg-4 in step S20.

[0056] On the other hand, in step 13, if the current state is an emergency state, the base station gNB rejects the communication terminal UE that has transmitted the first message Msg-1 including RedCap information. In this case, the base station gNB does not transmit the second message Msg-2 to the communication terminal UE in step S14, or transmits to the communication terminal UE a message indicating that communication with the communication terminal UE is rejected instead of the second message Msg-2 in step S14. Therefore, if the current state is an emergency state, the communication terminal UE as a RedCap UE cannot transmit the third message Msg-3 to the base station gNB in ​​step S16 shown in FIG. 5. In other words, the communication terminal UE is rejected from connection by the base station gNB, and therefore cannot use the function as a RedCap UE. Note that even in this case, normal communication terminals that are not RedCap UEs can communicate with the base station gNB.

[0057] FIG. 6 is a schematic diagram for explaining a communication terminal UE that can communicate with a base station gNB in ​​an emergency state and a communication terminal UE that cannot communicate with a base station gNB in ​​an emergency state in a communication system CS of a comparative example.

[0058] The communication terminal UE1, the communication terminal UE2, the communication terminal UE3, and the communication terminal UES shown in FIG. 6 are all specific communication terminals, for example, RedCap UEs, similar to those shown in FIG.

[0059] As can be seen from Fig. 6, according to the communication method described using Fig. 5, in an emergency state, not only the communication terminals UE1, UE2, and UE3 but also the communication terminal UES that transmits medical vital information cannot communicate with the base station gNB. Therefore, in an emergency state, the medical vital information becomes unavailable, which may result in a situation where appropriate medical care cannot be provided.

[0060] In other words, according to the communication method of Figure 5, in an emergency state, none of the communication terminals UE, UE2, UE3, and UES as RedCap UEs can communicate with other communication terminals via the base station gNB and the network NW.

[0061] From the above, it can be seen that according to the communication methods of Figures 3 and 4, unlike the communication methods of the comparative examples of Figures 5 and 6, a communication terminal UE as a RedCap UE can use the communication functions as a RedCap UE even if its current state is an emergency state.

[0062] 7 is a flowchart illustrating a process executed by a terminal control unit TP of a communication terminal UE of a communication system CS according to an embodiment. The process illustrated in FIG. 7 is a Random Access Channel (RACH) process that is first performed by a communication terminal UE to communicate with a base station gNB in ​​a 5G mobile communication system.

[0063] In step S101, the terminal control unit TP of the communications terminal UE determines whether the current state is a normal state or an emergency state.

[0064] In this embodiment, the user determines whether the state is normal or emergency based on disaster information and the like notified by the government. By operating the terminal operation unit TO, state information indicating whether the current state is normal or emergency is transmitted to the terminal control unit TP. This allows the user of the RedCap UE to select whether to use the communication function of the RedCap UE in an emergency.

[0065] However, as described above, the terminal control unit TP may automatically determine whether the state is normal or emergency, for example, based on disaster information notified by the government, etc. In this case, in step S101, the terminal control unit TC receives state information indicating whether the current state is normal or emergency from outside the communications terminal UE via the terminal communications unit TC.

[0066] If it is determined in step S101 that the current state is a normal state, then in step S102 the terminal control unit TP includes RedCap information in a first message Msg-1 and causes the terminal communication unit TC to transmit the first message Msg-1 to the base station gNB. On the other hand, if it is determined in step S101 that the current state is an emergency state, then in step S103 the terminal control unit TP includes RedCap information in a third message Msg-3 and causes the terminal communication unit TC to transmit the third message Msg-3 to the base station gNB.

[0067] However, the terminal control unit TP of the communications terminal UE may always include RedCap information in the third message Msg-3 and transmit the third message Msg-3 to the base station gNB without executing the determination process shown in Fig. 7. This allows the user of this RedCap UE to always use the communication functions of the RedCap UE in an emergency state without changing any settings of the communications terminal UE.

[0068] 8 is a flowchart illustrating a process executed by a base station control unit BP of a base station gNB of a communication system CS according to an embodiment. The process illustrated in FIG. 8 is a RACH process that is first performed by a base station gNB to communicate with a communication terminal UE in accordance with the 5G mobile communication system standard.

[0069] In step S201, the base control unit BP determines whether or not specific terminal information, for example, RedCap information, is included in the first message Msg-1 transmitted from the communication terminal UE and received by the base communication unit BC. If it is determined in step S201 that specific terminal information is included in the first message Msg-1, the base control unit BP determines in step S202 whether the current state is a normal state or an emergency state. Specifically, the base control unit BP determines whether or not connection to the network NW of a specific communication terminal, for example, a communication terminal UE as a RedCap UE, is restricted.

[0070] In this embodiment, for example, based on disaster information notified by the government, the user determines whether the state is normal or emergency. Then, by operating the base operation unit BO, status information indicating either the normal state or the emergency state is transmitted to the base control unit BP.

[0071] However, as described above, the base station control unit BP may automatically determine whether the state is normal or emergency, for example, based on disaster information notified by the government, etc. In this case, in step S202, the base station control unit BP receives state information indicating whether the state is normal or emergency from outside the base station gNB via the base station communication unit BC.

[0072] If the current state is an emergency state in step S202, the base station controller BP does not allow the communication terminal UE to use the communication function as a specific communication terminal in step S203. More specifically, if the connection of the specific communication terminal to the network NW is restricted in step S202, the base station controller BP rejects the connection of the communication terminal UE as a RedCap UE to the network NW in step S203. Therefore, the communication terminal UE cannot communicate with other communication terminals etc. via the base station gNB.

[0073] On the other hand, if the current state is a normal state in step S202, the base station control unit BP performs configuration in step S204 to cause the communication terminal UE to use a communication function as a specific communication terminal. More specifically, if the connection of the specific communication terminal is not restricted in step S202, the base station control unit BP performs configuration in step S204 to cause the communication terminal UE to use a communication function as a RedCap UE. This allows the communication terminal UE as a RedCap UE to communicate with other communication terminals via the base station gNB.

[0074] Furthermore, if it is determined in step S201 that the first message Msg-1 does not include specific terminal information, then in step S205 the base control unit BP performs configuration on the communications terminal UE to allow it to use the communications functions of a normal communications terminal. More specifically, if it is determined that the first message Msg-1 does not include RedCap information, then in step S205 the base control unit BP performs configuration on the communications terminal UE to allow it to use the communications functions of a normal communications terminal. Therefore, the base control unit BP causes the base communication unit BT to transmit a message Msg-2 to the communications terminal UE. Thereafter, the base control unit BP receives a third message Msg-3 from the communications terminal UE. As a result, in step S206 the base control unit BP determines whether or not specific terminal information is included in the third message Msg-3 received by the base communication unit BT.

[0075] If it is determined in step S206 that the third message Msg-3 contains specific terminal information, then in step S204 the base station controller BP performs configuration to cause the communication terminal UE to use the communication function as a RedCap UE. This allows the communication terminal UE as a RedCap UE to communicate with other communication terminals, etc., via the base station gNB. On the other hand, if it is determined in step S206 that the third message Msg-3 does not contain specific terminal information, then in step S207 the base station controller BP continues configuration to cause the communication terminal UE to use the communication function as a normal communication terminal. Therefore, the base controller BP causes the base communication unit BT to transmit a message Msg-4 to the communication terminal UE.

[0076] The characteristic configuration of the communication method by the communication system CS of the above embodiment is as follows.

[0077] (1) The communication terminal UE includes a terminal communication unit TC that performs wireless communication with the base station gNB and a terminal control unit TP that controls the terminal communication unit. The terminal control unit TP causes the terminal communication unit TC to transmit a first message Msg to the base station gNB in ​​the wireless communication without including specific terminal information indicating that the communication terminal UE is a specific communication terminal that may be restricted in use by the base station gNB. The terminal control unit TP receives a second message Msg-2 as a response to the first message Msg-1 from the base station gNB via the terminal communication unit TC. The terminal control unit TP includes the specific terminal information in subsequent messages, such as a third message Mg-3 as a response to the second message Msg-2, and causes the terminal communication unit TC to transmit the subsequent messages to the base station gNB. According to this, since the first message Msg-1 does not include the specific terminal information, the base station gNB will not reject the connection with the communication terminal UE if the first message Msg-1 includes the specific terminal information. Therefore, the communication terminal UE can use the communication function of the specific communication terminal even in an emergency.

[0078] (2) The terminal control unit TP determines whether the current state is a normal state or an emergency state different from the normal state. In the normal state, the terminal control unit TP includes specific terminal information in a first message Msg-1 and causes the terminal communication unit TC to transmit the first message Msg-1 to the base station gNB. On the other hand, in the emergency state, the terminal control unit TP includes specific terminal information in a subsequent message and causes the terminal communication unit TC to transmit the subsequent message to the base station gNB. In this way, the communication terminal UE is switched to either the usage mode used in the normal state or the usage mode used in the emergency state.

[0079] (3) The communications terminal UE further comprises a terminal operation unit TO that is operated by the user. When the user performs a predetermined operation, the terminal operation unit TO transmits state information indicating whether the current state is a normal state or an emergency state to the terminal control unit TP. This allows the user of the communications terminal UE to set either the normal state or the emergency state as the current state of the communications terminal UE by himself / herself. Therefore, the user of the communications terminal UE can select, at his / her own discretion, whether or not to use the communication functions of the communications terminal UE, which is a specific communications terminal, in an emergency state.

[0080] (4) The terminal control unit TP receives state information indicating either a normal state or an emergency state from outside the communications terminal UE via the terminal communication unit TC. This allows the terminal control unit TP to automatically distinguish whether the current state is a normal state or an emergency state without the user's decision. As a result, the communications terminal UE automatically switches to either the normal state usage mode or the emergency state usage mode without the user's decision.

[0081] (5) The specific terminal information is information indicating that some of the communication functions of the specific communication terminal are restricted compared to the communication functions of a normal communication terminal that is not a specific communication terminal. Even if the communication terminal UE is a specific communication terminal in which some of the communication functions are restricted compared to the communication functions of a normal communication terminal, the user of the communication terminal UE can use the communication functions of the specific communication terminal in an emergency.

[0082] (6) The base station gNB includes a base communication unit BC that performs wireless communication with the communication terminal UE and a base control unit BP that controls the base communication unit BC. The base control unit BP receives a first wireless communication message Msg-1 from the communication terminal UE via the base communication unit BC. The first message Msg-1 may not include specific terminal information indicating that the communication terminal UE is a specific communication terminal whose use may be restricted by the base station gNB. In this case, the base control unit BP causes the base communication unit PC to transmit a second message Mg-2 to the communication terminal UE as a response to the first message Msg-1. The base control unit BP receives subsequent messages from the communication terminal UE, including a third message Mg-3 as a response to the second message Mg-2. If the subsequent messages include specific terminal information, the base control unit BP can allow the communication terminal UE to use the communication functions of the specific communication terminal. This allows the base station gNB to allow the communication terminal UE to use the communication functions of the specific communication terminal even in an emergency.

[0083] (7) The base control unit BP determines whether the current state is a normal state or an emergency state different from the normal state. In the normal state, the base control unit BP allows the communication terminal UE to use the communication functions as a specific communication terminal even if the first message Msg-1 includes specific terminal information. On the other hand, in the emergency state different from the normal state, the base control unit BP does not allow the communication terminal UE to use the communication functions as a specific communication terminal if the first message Msg-1 includes specific terminal information. Furthermore, the base control unit BP allows the communication terminal UE to use the communication functions as a specific communication terminal if the subsequent message includes specific terminal information. According to this, the base station gNB is switched to either a response mode for the communication terminal UE in the normal state or a response mode for the communication terminal UE in the emergency state.

[0084] (8) The base station gNB further includes a base station operation unit BO that is operated by a user. When the user performs a predetermined operation, the base station operation unit BO transmits state information indicating whether the current state is a normal state or an emergency state to the base station control unit BP. This allows the administrator of the base station gNB to select, at its own discretion, either the normal state response mode or the emergency state response mode as the current state of the base station gNB. Therefore, the administrator of the base station gNB can select, at its own discretion, whether or not to allow a communication terminal UE, which is a specific communication terminal, to use the communication functions of the specific communication terminal in an emergency state.

[0085] (9) The base station controller BP receives state information indicating whether the base station gNB is in a normal state or a regular state from outside the base station gNB via the base station communication unit BC. This allows the base station controller BP to automatically distinguish whether the current state is a normal state or an emergency state without the user's decision. As a result, the response mode of the base station gNB automatically switches to either the normal state response mode or the emergency state response mode without the user's decision.

[0086] (10) If the subsequent message does not include specific terminal information, the base station control unit BP allows the communication terminal UE to use the communication functions of a normal communication terminal, not a specific communication terminal. According to this, the base station gNB can allow a normal communication terminal, not a specific communication terminal, to use the communication functions of a normal communication terminal, both in a normal state and an emergency state.

[0087] (11) The specific terminal information is information indicating that some of the communication functions of the specific communication terminal are restricted. Even if the communication terminal UE is a specific communication terminal in which some of the communication functions are restricted compared to the communication functions of a normal communication terminal that is not a specific communication terminal, the administrator of the base station gNB can allow the communication terminal UE to use the communication functions as a specific communication terminal in an emergency.

[0088] (12) The terminal program is for causing a computer to operate as each part of the above-mentioned communication terminal UE.

[0089] (13) The base station program is intended to cause a computer to operate as each part of the base station gNB described above.

[0090] (14) The communication system CS includes the communication terminal UE and the base station gNB.

[0091] (15) The communication method is carried out between the communication terminal UE and the base station gNB.

Claims

1. a terminal communication unit that performs wireless communication with a base station; A communication terminal including a terminal control unit that controls the terminal communication unit, The terminal control unit causing the terminal communication unit to transmit the first message of the wireless communication to the base station without including specific terminal information indicating that the communication terminal is a specific communication terminal that may be restricted in use by the base station; receiving a second message as a response to the first message from the base station via the terminal communication unit; causing the terminal communication unit to include the specific terminal information in subsequent messages after a third message as a response to the second message and transmit the subsequent messages to the base station; Furthermore, the terminal control unit determining whether the current state is a normal state or an emergency state different from the normal state; In the normal state, the specific terminal information is included in the first message, and the terminal communication unit transmits the first message to the base station, In the emergency state, the subsequent message includes the specific terminal information, and the subsequent message is transmitted to the base station by the terminal communication unit. Communications terminal.

2. Further comprising a terminal operation unit operated by a user, 2. The communication terminal according to claim 1, wherein the terminal operation unit transmits, when a predetermined operation is performed by a user, state information indicating whether a current state is the normal state or the emergency state to the terminal control unit.

3. The communication terminal according to claim 1 , wherein the terminal control unit receives state information indicating whether the communication terminal is in the normal state or the emergency state from outside the communication terminal via the terminal communication unit.

4. A communication terminal according to any one of claims 1 to 3, wherein the specific terminal information is information indicating that some of the communication functions of the specific communication terminal are restricted compared to the communication functions of a normal communication terminal that is not the specific communication terminal.

5. a base communication unit that performs wireless communication with the communication terminal; a base station control unit that controls the base communication unit, The base control unit receiving a first message of the wireless communication from the communication terminal via the base communication unit; when the first message does not include specific terminal information indicating that the communication terminal is a specific communication terminal that may be restricted in use by the base station, causing the base station communication unit to transmit a second message to the communication terminal as a response to the first message; receiving subsequent messages from the communication terminal in response to the second message; If the specific terminal information is included in the subsequent message, the communication terminal is caused to use a communication function as the specific communication terminal; The base control unit determining whether the current state is a normal state or an emergency state different from the normal state; In the normal state, even if the first message includes the specific terminal information, the communication terminal is allowed to use a communication function as the specific communication terminal, In the emergency state, if the specific terminal information is included in the first message, the communication terminal is not allowed to use the communication function as the specific communication terminal, but if the specific terminal information is included in the subsequent message, the communication terminal is allowed to use the communication function as the specific communication terminal. Base station.

6. Further provided is a base operation unit operated by a user, 6. The base station according to claim 5, wherein the base operation unit transmits, to the base control unit, status information indicating whether the current status is the normal status or the emergency status when a predetermined operation is performed by a user.

7. The base station according to claim 5, wherein said base station control unit receives state information indicating whether said base station is in said normal state or said emergency state from outside said base station via said base station communication unit.

8. When the specific terminal information is not included in the subsequent message, the base station control unit causes the communication terminal to use a communication function as a normal communication terminal other than the specific communication terminal. The base station according to any one of claims 5 to 7.

9. The specific terminal information is information indicating a communication terminal in which some of the communication functions of the specific communication terminal are restricted compared to a normal communication terminal that is not the specific communication terminal. The base station according to any one of claims 5 to 7.

10. A computer-readable terminal program for causing a computer to operate as a terminal control unit that controls a terminal communication unit that performs wireless communication with a base station in a communication terminal, The terminal control unit causing the terminal communication unit to transmit the first message of the wireless communication to the base station without including specific terminal information indicating that the communication terminal is a specific communication terminal that may be restricted in use by the base station; receiving a second message as a response to the first message from the base station via the terminal communication unit; causing the terminal communication unit to include the specific terminal information in subsequent messages after a third message as a response to the second message and transmit the subsequent messages to the base station; Furthermore, the terminal control unit determining whether the current state is a normal state or an emergency state different from the normal state; In the normal state, the specific terminal information is included in the first message, and the terminal communication unit transmits the first message to the base station, In the emergency state, the subsequent message includes the specific terminal information, and the subsequent message is transmitted to the base station by the terminal communication unit. Terminal program.

11. A computer-readable base station program for causing a computer to operate as a base station control unit that controls a base communication unit that performs wireless communication with a communication terminal in a base station, The base control unit receiving a first message of the wireless communication from the communication terminal via the base communication unit; when the first message does not include specific terminal information indicating that the communication terminal is a specific communication terminal that may be restricted in use by the base station, causing the base station communication unit to transmit a second message to the communication terminal as a response to the first message; receiving subsequent messages from the communication terminal in response to the second message; If the specific terminal information is included in the subsequent message, the communication terminal is caused to use a communication function as the specific communication terminal; Furthermore, the base control unit determining whether the current state is a normal state or an emergency state different from the normal state; In the normal state, even if the first message includes the specific terminal information, the communication terminal is allowed to use a communication function as the specific communication terminal, In the emergency state, if the specific terminal information is included in the first message, the communication terminal is not allowed to use the communication function as the specific communication terminal, but if the specific terminal information is included in the subsequent message, the communication terminal is allowed to use the communication function as the specific communication terminal. Base program.

12. A communication system comprising a communication terminal and a base station that performs wireless communication with the communication terminal, the communication terminal transmits a first message of the wireless communication to the base station without including specific terminal information indicating that the communication terminal is a specific communication terminal that may be restricted in use by the base station in the first message of the wireless communication; Furthermore, the communication terminal determining whether the current state is a normal state or an emergency state different from the normal state; In the normal state, the specific terminal information is included in the first message, and the first message is transmitted to the base station; In the emergency state, the subsequent message includes the specific terminal information, and the subsequent message is transmitted to the base station; the base station receives the first message from the communication terminal and transmits a second message to the communication terminal as a response to the first message; the communication terminal receives the second message from the base station, includes the specific terminal information in the subsequent messages after a third message as a response to the second message, and transmits the subsequent messages to the base station; the base station receives the subsequent message from the communication terminal, and when the subsequent message includes the specific terminal information, causes the communication terminal to use a communication function as the specific communication terminal; Furthermore, the base station determining whether the current state is a normal state or an emergency state different from the normal state; In the normal state, even if the first message includes the specific terminal information, the communication terminal is allowed to use a communication function as the specific communication terminal, In the emergency state, if the specific terminal information is included in the first message, the communication terminal is not allowed to use the communication function as the specific communication terminal, but if the specific terminal information is included in the subsequent message, the communication terminal is allowed to use the communication function as the specific communication terminal. Communication system.

13. A communication method between a communication terminal and a base station that performs wireless communication with the communication terminal, The communication terminal transmitting a first message of the wireless communication to the base station without including specific terminal information indicating that the communication terminal is a specific communication terminal that may be restricted in use by the base station; Furthermore, the communication terminal determines whether the current state is a normal state or an emergency state different from the normal state; In the normal state, the specific terminal information is included in the first message, and the first message is transmitted to the base station; In the emergency state, the subsequent message includes the specific terminal information, and the subsequent message is transmitted to the base station; the base station receives the first message from the communication terminal and transmits a second message to the communication terminal as a response to the first message; the communication terminal receives the second message from the base station, includes the specific terminal information in the subsequent messages after a third message as a response to the second message, and transmits the subsequent messages to the base station; the base station receives the subsequent message from the communication terminal, and when the subsequent message includes the specific terminal information, causes the communication terminal to use a communication function as the specific communication terminal; Furthermore, the base station determining whether the current state is a normal state or an emergency state different from the normal state; In the normal state, even if the first message includes the specific terminal information, the communication terminal is allowed to use a communication function as the specific communication terminal, In the emergency state, if the specific terminal information is included in the first message, the communication terminal is not allowed to use the communication function as the specific communication terminal, but if the specific terminal information is included in the subsequent message, the communication terminal is allowed to use the communication function as the specific communication terminal. Communication method.

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