JP7523927B2 - Repeater - Google Patents

Description

The present invention relates to a relay device that relays information for call control between a terminal belonging to a specific communication network and a call control device.

For example, a service is provided in which a terminal (e.g., a fixed telephone device) belonging to a specific communication network established within a company base, etc., is connected to a mobile phone network, thereby connecting the fixed telephone device and a mobile phone as an internal line. In providing such a service, a relay device that relays various information for call control is provided between a control device group that performs call control between the mobile phone network and the fixed telephone device, and the fixed telephone device. The control device group includes a call control device having a PBX function for connecting a fixed telephone device in a specific communication network and a specific mobile phone as an internal line. In order for each terminal to be controlled by the call control device, the information of the terminal needs to be registered in the call control device. For example, Patent Document 1 describes a technology in which, in response to a register registration request for a terminal, a server registers the registration information included in the register registration request in a table in association with the outside line number of the terminal.

JP 2006-174110 A

In order to relay appropriate information between the call control device and the terminal, the relay device recognizes the correspondence between the call control device and the terminal based on a response signal returned from the call control device in response to a registration request from the terminal. Meanwhile, a redundant configuration may be adopted for call control devices with PBX functionality in preparation for failures, etc. Some call control devices in a redundant configuration may not return a response signal to a registration request from the terminal. In such cases, the relay device cannot recognize the association between some of the call control devices and the terminal, and cannot relay appropriate information.

The present invention was made in consideration of the above problems, and aims to provide a relay device that enables call control by appropriately relaying information related to call control, even if some of the call control devices in a redundant configuration are not recognized.

In order to solve the above problem, a relay device according to one embodiment of the present invention is a relay device that relays information for call control between a terminal belonging to a specific communication network and a plurality of call control devices including at least a first call control device and a second call control device that are configured to perform call control for the terminal and are configured to be redundant with each other, and includes a request unit that transmits a registration request to the call control device based on a request from the terminal to have the terminal recognized as a target of call control, a registration information registration unit that stores registration information that associates the terminal with the call control device in a predetermined storage means when a response signal is returned from the call control device in response to the registration request, and a relay unit that relays the incoming call request to the terminal when an incoming call request for the terminal is received from the call control device and the registration information that associates the call control device with the terminal is stored in the storage means, and when an incoming call request for the terminal is received from the second call control device and the registration information that associates the second call control device with the terminal is not stored in the storage means, the relay unit relays the incoming call request to the terminal when the registration information that associates the first call control device with the terminal is stored in the storage means.

According to the above embodiment, when an incoming call request for a terminal is received from a second call control device, even if registration information associating the second call control device with the terminal is not stored in advance, registration information associating the first call control device having a redundant relationship with the second call control device with the terminal is searched for, and if registration information related to the first call control device is stored, the incoming call request is relayed to the terminal. Therefore, even if information related to the second call control device based on the reception of a response signal is not held in advance and the association between the second call control device and the terminal is not recognized, the incoming call request for the terminal can be appropriately relayed. In addition, since there is no need to store information related to the second call control device in advance, resources for storing information are saved.

It is possible to provide a relay device that enables call control by appropriately relaying information related to call control even if some of the redundantly configured call control servers are not recognized.

1 is a diagram illustrating an example of a network configuration and a device configuration of a communication system including a relay device according to an embodiment of the present disclosure. FIG. 2 is a functional block diagram showing a functional configuration of a relay device according to the present embodiment. FIG. 2 is a hardware block diagram of a relay device. 4 is a timing chart showing an operation of the relay device. 4A and 4B are diagrams illustrating an example of the configuration of registration information stored in a registration information storage unit and an example of stored data. FIG. 11 is a diagram illustrating an example of correspondence information. FIG. 4 is a diagram showing a configuration of a relay program.

An embodiment of a relay device according to the present invention will be described with reference to the drawings. Whenever possible, identical parts will be given the same reference numerals and duplicated descriptions will be omitted.

FIG. 1 is a diagram illustrating a schematic network configuration and device configuration of a communication system including a relay device 10 according to an embodiment of the present disclosure. As shown in FIG. 1, the relay device 10 is configured to relay information via a communication network between base networks N1, N2 established at specific bases and a control server group SV.

The base network N (N1, N2) is a communication network constructed, for example, at a base of a company or the like. The base network N may include a PBX device PX, a fixed telephone T1 which is an example of a terminal T, and a mobile terminal T2 which is an example of a terminal T. The PBX device PX is an exchange for the telephone lines of the base network N, and provides the fixed telephone T1 with the function of an internal telephone by performing call control, etc. for the fixed telephone T1. As described later, the mobile terminal T2 can communicate as a so-called external line with a communication terminal belonging to the mobile phone network MN through control by a SIP server SP, etc. included in the control server group SV, and can also function as an internal terminal within the base of a company or the like.

The control server group SV is a server group for performing call control for terminals T belonging to the base network N, and includes a SIP server SP (call control device). The control server group SV is located between the base network N and the mobile phone network MN, and performs call control for incoming and outgoing calls for the fixed telephone T1 and mobile terminal T2 within the base network N.

The SIP server SP employs a redundant configuration, and in this embodiment, for example, includes two SIP servers, SIP server (1) SP1 (first call control device) and SIP server (2) SP2 (second call control device). In the redundant SIP server SP, for example, the SIP server (1) SP1 is operated as the active system, and in the event of a failure such as a breakdown in the SIP server (1) SP1, the backup SIP server (2) SP2 is operated.

The SIP server SP functions as a virtual PBX device that performs line switching for the fixed telephone T1 and mobile terminal T2 within the base network N, outside the base network N. In other words, the SIP server SP can provide the fixed telephone T1 and mobile terminal T2 with the function of an internal telephone.

The SIP server SP needs to recognize the terminal T in order to control the calls of the terminal T. To make the SIP server SP recognize the terminal T, the SIP server SP receives a registration request sent from the terminal T and registers the terminal T related to the received registration request as a terminal under its control. When the registration is complete, the SIP server SP returns a response signal to the terminal T that sent the registration request.

Figure 2 is a functional block diagram showing the functional configuration of the relay device 10 of this embodiment. The relay device 10 is called an SBC (Session Border Controller) and is a device that relays information for call control between a terminal T and a SIP server SP as a call control device. As shown in Figure 2, the relay device 10 includes a registration request acquisition unit 11, a request unit 12, a response signal acquisition unit 13, a registration information registration unit 14, an incoming request reception unit 15, and a relay unit 16. The relay device 10 may also include a registration information storage unit 18 for storing the registration information. In this embodiment, the registration information storage unit 18 is configured in the relay device 10, but may also be configured in another device configured to be able to communicate with the relay device 10.

As part of the relay process for information for call control, the relay device 10 performs processes such as conversion between network addresses in the base network N and network addresses in the control server group SV. To perform such relay process, the relay device 10 needs to recognize the association between the SIP server SP and the terminal T.

Specifically, the relay device 10 stores registration information associating the SIP server SP with the terminal T in the registration information storage unit 18, and when relaying information between the SIP server SP and the terminal T, it refers to the registration information storage unit 18 to search for registration information associating the SIP server SP with the terminal T, and relays the information if the registration information is registered.

When the relay device 10 receives a response signal returned by the SIP server SP in response to a registration request from the terminal T, it generates registration information that associates the terminal T with the SIP server SP, and stores the generated registration information in the registration information storage unit 18.

The block diagram shown in FIG. 2 shows functional blocks. These functional blocks (components) are realized by any combination of hardware and/or software. Furthermore, there are no particular limitations on the means of realizing each functional block. That is, each functional block may be realized by one device that is physically and/or logically coupled, or may be realized by two or more devices that are physically and/or logically separated and directly and/or indirectly (e.g., wired and/or wirelessly) connected to each other and these multiple devices.

Functions include, but are not limited to, judgement, determination, judgment, calculation, computation, processing, derivation, investigation, search, confirmation, reception, transmission, output, access, resolution, selection, selection, establishment, comparison, assumption, expectation, regard, broadcasting, notifying, communicating, forwarding, configuring, reconfiguring, allocating, mapping, and assignment. For example, a functional block (component) that performs the transmission function is called a transmitting unit or transmitter. As mentioned above, there are no particular limitations on the method of realization for either of these.

For example, the relay device 10 in one embodiment of the present invention may function as a computer. FIG. 3 is a diagram showing an example of the hardware configuration of the relay device 10 according to this embodiment. The relay device 10 may be physically configured as a computer device including a processor 1001, a memory 1002, a storage 1003, a communication device 1004, an input device 1005, an output device 1006, a bus 1007, etc.

In the following description, the term "apparatus" may be interpreted as a circuit, device, unit, etc. The hardware configuration of the relay device 10 may be configured to include one or more of the devices shown in FIG. 3, or may be configured to exclude some of the devices.

Each function of the relay device 10 is realized by loading a specific software (program) onto hardware such as the processor 1001 and memory 1002, causing the processor 1001 to perform calculations and control communication by the communication device 1004 and the reading and/or writing of data in the memory 1002 and storage 1003.

The processor 1001, for example, runs an operating system to control the entire computer. The processor 1001 may be configured as a central processing unit (CPU) including an interface with peripheral devices, a control unit, an arithmetic unit, registers, etc. The processor 1001 may also be configured to include a GPU (Graphics Processing Unit). For example, the functional units 11 to 16 shown in FIG. 2 may be realized by the processor 1001.

The processor 1001 also reads out programs (program codes), software modules, and data from the storage 1003 and/or the communication device 1004 into the memory 1002, and executes various processes according to these. The programs used are those that cause a computer to execute at least some of the operations described in the above-mentioned embodiments. For example, the functional units 11 to 16 of the relay device 10 may be realized by a control program stored in the memory 1002 and operated by the processor 1001. Although the above-mentioned various processes have been described as being executed by one processor 1001, they may be executed simultaneously or sequentially by two or more processors 1001. The processor 1001 may be implemented in one or more chips. The programs may be transmitted from a network via a telecommunications line.

The memory 1002 is a computer-readable recording medium, and may be composed of at least one of, for example, a read only memory (ROM), an erasable programmable ROM (EPROM), an electrically erasable programmable ROM (EEPROM), a random access memory (RAM), etc. The memory 1002 may also be called a register, a cache, a main memory (primary storage device), etc. The memory 1002 can store executable programs (program codes), software modules, etc., for implementing a relay method according to one embodiment of the present invention.

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

The communication device 1004 is hardware (transmitting/receiving device) for communicating between computers via a wired and/or wireless network, and is also referred to as, for example, a network device, a network controller, a network card, a communication module, etc.

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

In addition, each device, such as the processor 1001 and memory 1002, is connected by a bus 1007 for communicating information. The bus 1007 may be configured as a single bus, or may be configured as different buses between the devices.

The relay device 10 may also be configured to include hardware such as a microprocessor, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a programmable logic device (PLD), or a field programmable gate array (FPGA), and some or all of the functional blocks may be realized by the hardware. For example, the processor 1001 may be implemented by at least one of these pieces of hardware.

The functional units of the relay device 10 will be described with reference to Figures 2 and 4. Figure 4 is a timing chart showing the operation of the relay device 10 of this embodiment. In addition to the relay device 10, Figure 4 shows the operation of terminal A (T), SIP server (1) SP1, and SIP server (2) SP2.

The terminal A (T) shown in FIG. 4 is a terminal T identified by an identifier A, and may be either a landline telephone T1 or a mobile terminal T2.

The SIP server SP is configured redundantly with two SIP servers, SIP server (1) SP1 and SIP server (2) SP2, each of which is identified by the number (1) and the number (2) as identification information. In the example shown in FIG. 4, the SIP server (1) SP1 is operated as the active system.

In step S1, terminal A (T) transmits a registration request to have the SIP server (1) SP1 recognize terminal A (T). The registration request acquisition unit 11 of the relay device 10 acquires the registration request transmitted from terminal A (T).

In step S2, the request unit 12 sends a registration request to the SIP server (1) SP1 based on the registration request from the terminal A (T).

In step S3, in response to the registration request relayed and transmitted by the relay device 10, the SIP server (1) SP1 recognizes and registers the terminal A (T) as a terminal to be controlled, and returns a response signal to the relay device 10 indicating that registration has been completed.
The response signal acquisition unit 13 of the relay device 10 receives the response signal returned from the SIP server (1) SP1.

In step S4, the registration information registration unit 14 generates registration information (terminal A-SIP server (1)) that associates terminal A (T), which is the sender of the registration request related to the response signal, with SIP server (1) SP1, which is the sender of the response signal and recognizes terminal A (T) as a control target, based on the received response signal, and stores the generated registration information in the registration information storage unit 18.

Figure 5 is a diagram showing an example of the configuration of registration information stored in the registration information storage unit 18 and the data stored therein. As shown in Figure 5, the registration information storage unit 18 stores "A", which is the identification information of the terminal A (T) related to the registration information, in association with the number "1", which is the identification information of the SIP server.

In step S5, the response signal acquisition unit 13 transmits the acquired response signal to terminal A(T).

In step S6, terminal A (T) transmits a registration request to SIP server (2) SP2, which is a backup SIP server, to recognize terminal A (T). The registration request acquisition unit 11 of the relay device 10 acquires the registration request sent from terminal A (T) and addressed to SIP server (2) SP2.

In step S7, the request unit 12 sends a registration request to the SIP server (2) SP2 based on the registration request from the terminal A (T).

The backup SIP server may be configured not to return a response signal in response to a registration request. In this embodiment, the SIP server (2) SP2 does not return a response signal in response to a registration request relayed and transmitted by the relay device 10.

After terminal T has been registered with the SIP server, while call control for incoming and outgoing calls to the terminal is being performed, a failure (AC) may occur in the active SIP server (1) SP1. In such a case, the SIP server (2) SP2 configured as the backup system is switched to the active system.

When the SIP server (2) SP2 is operated as the active system in this way, incoming calls to terminal A (T) from the mobile phone network MN, etc. are accepted by the SIP server (2) SP2 (step S11).

In step S12, the SIP server (2) SP2 sends an incoming call request for terminal A (T) to the relay device 10. The incoming call request receiving unit 15 of the relay device 10 receives the incoming call request sent from the SIP server (2) SP2.

When the relay unit 16 receives an incoming call request from the SIP server SP to the terminal T, if registration information associating the SIP server SP with the terminal T is stored in the registration information storage unit 18, the relay unit 16 relays the incoming call request to the terminal T.

In step S13 illustrated in the timing chart of FIG. 4, the relay unit 16 refers to the registration information storage unit 18 to search for registration information that associates terminal A, which is the destination of the incoming request received in step S12, with the SIP server (2) SP2, which is the sender of the incoming request. However, as shown in FIG. 5, the registration information storage unit 18 does not have any registration information that associates terminal A with the SIP server (2) SP2, so at this point in time, the relay device 10 cannot recognize terminal A as a target to which information from the SIP server SP should be relayed.

When the relay unit 16 receives an incoming call request from the SIP server (2) SP2 to the terminal A (T), if the registration information associating the SIP server (2) SP2 with the terminal A (T) is not stored in the registration information storage unit 18, and if the registration information associating the SIP server (1) SP1, which is a SIP server SP that has a redundant relationship with the SIP server (2) SP2, with the terminal A (T) is stored in the registration information storage unit 18, the relay unit 16 relays the incoming call request to the terminal A (T).

Specifically, in step S14, the relay unit 16 calculates a number by adding or subtracting 1 from the number that is the identification information of the SIP server (2) included in the incoming request, and searches for whether or not registration information that associates the identification information "A" of terminal A (T) with the calculated number that is the identification information of the SIP server is stored in the registration information storage unit 18.

More specifically, if the number of the identification information included in the incoming request is an odd number, the relay unit 16 adds 1 to the number of the identification information to calculate the number of the identification information for re-searching, and if the number of the identification information included in the incoming request is an even number, the relay unit 16 subtracts 1 from the number of the identification information to calculate the number of the identification information for re-searching.

In step S14 of this embodiment, the relay unit 16 subtracts 1 from the number "2", which is the identification information of the SIP server (2) included in the incoming request, to calculate the number "1", which is the identification information for a second search. The relay unit 16 then searches whether or not registration information that associates the identification information "A" of the terminal A (T) with the calculated number "1", which is the identification information that identifies the SIP server (1) SP1, is stored in the registration information storage unit 18. As shown in FIG. 5, the registration information storage unit 18 has registration information that associates the terminal A with the SIP server (1) SP1 registered, and the relay device 10 can recognize the terminal A as a target to which information from the SIP server SP should be relayed.

In step S15, the relay unit 16 relays and transmits the incoming call request to terminal A(T).

In the example described with reference to FIG. 4, the relay unit 16 adds or subtracts 1 from the number of the identification information included in the incoming request to calculate the identification information for re-searching the registration information storage unit 18, but the present invention is not limited to this example. The relay unit 16 may obtain the identification information of the SIP server for re-searching the registration information storage unit 18 by referring to correspondence information that associates SIP servers that are in a redundant relationship with each other.

Figure 6 is a diagram showing an example of correspondence information that associates SIP servers that are in a redundant relationship with each other. The correspondence information may be stored, for example, in a storage means accessible from the relay device 10.

Specifically, when the relay unit 16 receives an incoming call request from the SIP server (2) SP2 to the terminal A (T), if the registration information associating the SIP server (2) SP2 with the terminal A (T) is not stored in the registration information storage unit 18, the relay unit 16 refers to the correspondence information shown in FIG. 6 to obtain that the SIP server (1) is associated as a SIP server having a redundant relationship with the SIP server (2), and searches whether the registration information associating the SIP server (1) SP1 with the terminal A (T) is stored in the registration information storage unit 18.

Then, when registration information associating the SIP server (1) SP1 with the terminal A (T) is stored in the registration information storage unit 18, the relay unit 16 can recognize the terminal A as a target to which information from the SIP server SP should be relayed, and therefore relays the incoming call request to the terminal A (T).

Next, we will explain the relay program that causes a computer to function as the relay device 10 of this embodiment. Figure 7 is a diagram showing the configuration of the relay program P1.

The relay program P1 is configured to include a main module m10 that controls the relay process in the relay device 10, a registration request acquisition module m11, a request module m12, a response signal acquisition module m13, a registration information registration module m14, an incoming request receiving module m15, and a relay module m16. The modules m11 to m16 realize the functions of the registration request acquisition unit 11, the request unit 12, the response signal acquisition unit 13, the registration information registration unit 14, the incoming request receiving unit 15, and the relay unit 16 in the relay device 10. The relay program P1 may be transmitted via a transmission medium such as a communication line, or may be stored in a recording medium M1 as shown in FIG. 7.

In the relay device 10 of the present embodiment described above, when an incoming request for terminal T is received from SIP server (2) SP1, even if registration information associating the SIP server (2) SP2 with the terminal T is not stored in advance, the relay device 10 searches for registration information associating the SIP server (1) having a redundant relationship with the SIP server (2) SP2 with the terminal T, and if registration information related to the SIP server (1) SP1 is stored, the incoming request is relayed to terminal T. Therefore, even if the relay device 10 does not have information about the SIP server (2) SP2 based on the reception of a response signal in advance and does not recognize the association between the SIP server (2) SP2 and terminal T, it can appropriately relay the incoming request for terminal T. In addition, since there is no need to store information about the SIP server (2) SP2 in advance, resources for storing information are saved.

In another embodiment of the relay device 10, each of the multiple call control devices is identified by a number, and each number is associated with each call control device as identification information, the registration information associates a terminal with the identification information of the call control device, the incoming call request includes the identification information of the sender call control device, and when the relay unit receives an incoming call request for a terminal from a second call control device, if the registration information associating the identification information of the second call control device included in the incoming call request with the terminal is not stored in the storage means, the relay unit may calculate a number obtained by adding or subtracting 1 from the number of the identification information included in the incoming call request as the identification information of the first call control device, and relay the incoming call request to the terminal if the registration information associating the terminal with the identification information of the first call control device is stored in the storage means.

According to the above embodiment, the identification information of the first call control device is calculated by adding or subtracting 1 from the number of the identification information included in the incoming call request. Therefore, with a simple configuration, it is possible to obtain the identification information for re-searching the registered information.

In another embodiment of the relay device 10, if the identification information included in the incoming request is an odd number, the relay unit may add 1 to the identification information number to calculate the identification information of the first call control device, and if the identification information included in the incoming request is an even number, the relay unit may subtract 1 from the identification information number to calculate the identification information of the first call control device.

According to the above embodiment, if the identification information of the redundant call control devices is configured to form a pair of odd and even numbers, when the identification information included in the acquired incoming request is an odd or even number, it is possible to reliably and easily obtain the identification information for re-searching the registered information by adding or subtracting 1 from the number of the identification information.

In another embodiment of the relay device 10, when an incoming call request for a terminal is received from a second call control device, if registration information associating the second call control device with the terminal is not stored in the storage means, the relay unit may refer to correspondence information associating call control devices that are in a redundant relationship with each other to obtain information about the first call control device associated with the second call control device, and if registration information associating the first call control device with the terminal is stored in the storage means, relay the incoming call request to the terminal.

According to the above embodiment, by referencing pre-stored correspondence information, information regarding the first call control device that is in a redundant relationship with the second call control device can be obtained, so that identification information for re-searching for registered information can be easily obtained.

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

The notification of information is not limited to the aspects/embodiments described in the present disclosure, and may be performed using other methods. For example, the notification of information may be performed by physical layer signaling (e.g., Downlink Control Information (DCI), Uplink Control Information (UCI)), higher layer signaling (e.g., Radio Resource Control (RRC) signaling, Medium Access Control (MAC) signaling, broadcast information (Master Information Block (MIB), System Information Block (SIB))), other signals, or a combination of these. In addition, the RRC signaling may be called an RRC message, and may be, for example, an RRC Connection Setup message, an RRC Connection Reconfiguration message, etc.

Each aspect/embodiment described in this disclosure may be applied to at least one of systems utilizing LTE (Long Term Evolution), LTE-Advanced (LTE-A), SUPER 3G, IMT-Advanced, 4G (4th generation mobile communication system), 5G (5th generation mobile communication system), FRA (Future Radio Access), NR (new Radio), W-CDMA (registered trademark), GSM (registered trademark), CDMA2000, UMB (Ultra Mobile Broadband), IEEE 802.11 (Wi-Fi (registered trademark)), IEEE 802.16 (WiMAX (registered trademark)), IEEE 802.20, UWB (Ultra-WideBand), Bluetooth (registered trademark), or other suitable systems, and next generation systems enhanced based on these. Additionally, multiple systems may be combined (for example, a combination of at least one of LTE and LTE-A with 5G, etc.).

The processing steps, sequences, flow charts, etc. of each aspect/embodiment described in this disclosure may be reordered unless inconsistent. For example, the methods described herein present elements of various steps in an example order and are not limited to the particular order presented.

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

Information, etc. may be output from a higher layer (or a lower layer) to a lower layer (or a higher layer). It may also be input and output via multiple network nodes.

The input and output information may be stored in a specific location (e.g., memory) or may be managed in a management table. The input and output information may be overwritten, updated, or added to. The output information may be deleted. The input information may be sent to another device.

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

Each aspect/embodiment described in this disclosure may be used alone, in combination, or switched depending on the execution. In addition, notification of specific information (e.g., notification that "X is the case") is not limited to being done explicitly, but may be done implicitly (e.g., not notifying the specific information).

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

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

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

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

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

In addition, the information, parameters, etc. described in this disclosure may be represented using absolute values, may be represented using relative values from a predetermined value, or may be represented using other corresponding information. For example, radio resources may be indicated by an index.

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

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

A base station can accommodate one or more (e.g., three) cells. When a base station accommodates multiple cells, the entire coverage area of the base station can be divided into multiple smaller areas, and each smaller area can also provide communication services by a base station subsystem (e.g., a small indoor base station (RRH: Remote Radio Head). The term "cell" or "sector" refers to a part or the entire coverage area of at least one of the base station and base station subsystems that provide communication services in this coverage.

In this disclosure, terms such as "Mobile Station (MS)," "user terminal," "User Equipment (UE)," and "terminal" may be used interchangeably.

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

At least one of the base station and the mobile station may be called a transmitting device, a receiving device, a communication device, etc. At least one of the base station and the mobile station may be a device mounted on a moving body, the moving body itself, etc. The moving body may be a vehicle (e.g., a car, an airplane, etc.), an unmanned moving body (e.g., a drone, an autonomous vehicle, etc.), or a robot (manned or unmanned). At least one of the base station and the mobile station may include a device that does not necessarily move during communication operation. For example, at least one of the base station and the mobile station may be an IoT (Internet of Things) device such as a sensor.

In addition, the base station in the present disclosure may be read as a user terminal. For example, each aspect/embodiment of the present disclosure may be applied to a configuration in which communication between a base station and a user terminal is replaced with communication between multiple user terminals (which may be called, for example, D2D (Device-to-Device) or V2X (Vehicle-to-Everything)). In this case, the user terminal may be configured to have the functions of the above-mentioned base station. Furthermore, terms such as "uplink" and "downlink" may be read as terms corresponding to terminal-to-terminal communication (for example, "side"). For example, the uplink channel, downlink channel, etc. may be read as a side channel.

Similarly, the user terminal in this disclosure may be interpreted as a base station. In this case, the base station may be configured to have the functions of the user terminal described above.

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

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

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

When designations such as "first," "second," and the like are used in this disclosure, any reference to that element is not intended to generally limit the quantity or order of those elements. These designations may be used herein as a convenient way to distinguish between two or more elements. Thus, a reference to a first and a second element does not imply that only two elements may be employed therein or that the first element must precede the second element in some way.

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

To the extent that the terms "include," "including," and variations thereof are used herein in the specification or claims, these terms are intended to be inclusive, similar to the term "comprising." Further, the term "or" as used herein is not intended to be an exclusive or.

In this disclosure, where articles have been added through translation, such as a, an, and the in English, this disclosure may include that the nouns following these articles are in the plural form.

10... relay device, 11... registration request acquisition unit, 12... request unit, 13... response signal acquisition unit, 14... registration information registration unit, 15... incoming call request reception unit, 16... relay unit, 18... registration information storage unit, M1... recording medium, m10... main module, m11... registration request acquisition module, m12... request module, m13... response signal acquisition module, m14... registration information registration module, m15... incoming call request reception module, m16... relay module, MN... mobile phone network, N, N1, N2... base network, P1... relay program, PX... PBX device, SP, SP1, SP2... SIP server, T... terminal.

Claims (2)

A relay device that relays information for call control between a terminal belonging to a specific communication network and a plurality of call control devices including at least a first call control device and a second call control device that are configured to be redundant with each other and perform call control of the terminal,
a request unit that transmits a registration request to the call control device based on a request from the terminal, for causing the terminal to be recognized as a target of call control;
a registration information registration unit that stores, in a predetermined storage means, registration information that associates the terminal with the call control device when a response signal is returned from the call control device in response to the registration request;
a relay unit that relays an incoming call request to the terminal when the registration information associating the call control device with the terminal is stored in the storage means when the call control device receives an incoming call request to the terminal from the call control device,
Each of the plurality of call control devices is identified by a number, and each number is associated with each call control device as identification information;
the registration information associates the terminal with the identification information of the call control device;
the call termination request includes the identification information of the call control device that is a source of the call termination request,
when the relay unit receives the incoming call request from the second call control device to the terminal, if the registration information associating the identification information of the second call control device included in the incoming call request with the terminal is not stored in the storage means, the relay unit calculates a number obtained by adding or subtracting 1 from the number of the identification information included in the incoming call request as the identification information of the first call control device, and if the registration information associating the terminal with the identification information of the first call control device is stored in the storage means, relays the incoming call request to the terminal.
Relay device. When the identification information included in the incoming call request is an odd number, the relay unit calculates a number obtained by adding 1 to the number of the identification information as the identification information of the first call control device, and when the identification information included in the incoming call request is an even number, the relay unit calculates a number obtained by subtracting 1 from the number of the identification information as the identification information of the first call control device.
The relay device according to claim 1 .

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