Improved service continuity across different networks

Abstract

Provided is a communication control device comprising at least one processor that executes: detecting a second network serving as a candidate for a switching destination of a communication instrument connected to a first network by a switching destination candidate detection unit; determining, on the basis of communication between the first network and the second network, whether or not the second network can continuously provide a service provided to the communication instrument by the first network to the communication instrument by a service provision propriety determination unit; and switching the connection destination of the communication instrument from the first network to the second network by a connection control unit if it is determined that the second network can continuously provide the service to the communication instrument (FIG. 2).

Description

[Technical Field]

[0001] The present disclosure relates to improving continuity of services across different networks. [Background technology]

[0002] The number, types, and uses of wireless communication devices, such as smartphones and Internet of Things (IoT) devices, are steadily increasing, and wireless communication standards are continually being expanded and improved. For example, commercial service for the fifth-generation mobile communication system, known as "5G," began in 2018, and standardization is still underway at the Third Generation Partnership Project (3GPP). In addition, efforts have begun to develop standards for the sixth-generation mobile communication system, or "6G," as the next-generation wireless communication standard following 5G.

[0003] Mobile communication (hereinafter also referred to as mobile communication) networks for mobile or portable communication devices (hereinafter collectively referred to as communication devices), such as smartphones and mobile phones, are generally constructed using communication cells (hereinafter also referred to as terrestrial communication cells) provided on the ground by base stations (hereinafter also referred to as terrestrial base stations) installed on the ground. Patent Document 1 discloses a technology for detecting degradation in communication quality between a communication device and a terrestrial base station, and for handing over the other communication device that caused the degradation to another terrestrial base station. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2013-207562 Summary of the Invention [Problem to be solved by the invention]

[0005] Wireless communication standards from 5G onward use terrestrial communication cells of a wide range of sizes, from femtocells with a radius of less than 10 meters to macrocells with a radius of over several hundred meters. Furthermore, in some regions, it may be difficult to install a sufficient number of terrestrial base stations for various reasons, and studies are underway to introduce non-terrestrial networks (NTNs) that provide communication cells on the ground (hereinafter also referred to as non-terrestrial communication cells, and communication cells provided by communication satellites in particular are also referred to as satellite communication cells) using communication satellites and unmanned aerial vehicles flying in outer space or the stratosphere as base stations, in addition to or instead of terrestrial networks (TNs) using terrestrial base stations.

[0006] In a mobile communication network in which a wide variety of base stations and communication cells can exist, handover control based solely on the communication quality of each base station, as in Patent Document 1, may not be appropriate. Furthermore, in a handover between different networks operated by different communication carriers, the communication quality of the destination network may be low, and there is a risk that the continuity of the service that the communication device received in the source network may be lost after the handover.

[0007] The present disclosure has been made in view of the above circumstances, and aims to provide a communication control device and the like that can improve the continuity of services in different networks. [Means for solving the problem]

[0008] In order to solve the above problem, a communication control device of one embodiment of the present disclosure includes at least one processor that performs the following operations: detecting, by a switching destination candidate detection unit, a second network that is a candidate switching destination for a communication device connected to a first network; determining, by a service provision feasibility determination unit, based on communication between the first network and the second network, whether the second network can continuously provide the communication device with the service that the first network provides to the communication device; and, if the connection control unit determines that the second network can continuously provide the service to the communication device, switching the connection destination of the communication device from the first network to the second network.

[0009] In this aspect, when it is determined that the second network can continuously provide the communication device with the services provided by the first network, the communication device's connection destination is switched from the first network to the second network, thereby improving the continuity of services across different networks.

[0010] Another aspect of the present disclosure is a communication control method, comprising: detecting a second network that is a candidate for a switchover destination of a communication device connected to a first network; determining, based on communication between the first network and the second network, whether the second network can continuously provide the communication device with a service currently provided to the communication device by the first network; and, if it is determined that the second network can continuously provide the service to the communication device, switching the communication device from the first network to the second network.

[0011] Yet another aspect of the present disclosure is a storage medium storing a communication control program that causes a computer to execute the following operations: detect a second network that is a candidate for a switchover destination of a communication device connected to a first network; determine, based on communication between the first network and the second network, whether the second network can continuously provide the communication device with a service that the first network provides to the communication device; and, if it is determined that the second network can continuously provide the service to the communication device, switch the connection destination of the communication device from the first network to the second network.

[0012] Any combination of the above components, or any conversion of these expressions into methods, devices, systems, recording media, computer programs, etc., are also encompassed within the present disclosure. [Effects of the Invention]

[0013] According to the present disclosure, it is possible to improve the continuity of services across different networks. [Brief explanation of the drawings]

[0014] [Figure 1] 1 shows a schematic overview of a wireless communication system to which a communication control device is applied. [Figure 2] FIG. 2 is a functional block diagram illustrating a communication control device. [Figure 3] 1 illustrates a schematic representation of a second PLMN that shares some of the network equipment with a first PLMN. [Figure 4] 2 shows a schematic representation of a second PLMN, which is a roaming network; [Figure 5] Four specific examples of service quality information collected by the service quality information collecting unit are shown below. [Figure 6] This diagram shows a schematic example of the procedure when an inquiry and response such as that shown in Figure 5 is made by an AF outside 5GC and an NEF and / or NWDAF within 5GC. DETAILED DESCRIPTION OF THE INVENTION

[0015] The communication control device according to the present disclosure can be applied to a terrestrial network (TN) constructed by terrestrial communication cells provided to the ground by terrestrial base stations installed on the ground, a non-terrestrial network (NTN) constructed by non-terrestrial communication cells provided to the ground by airborne non-terrestrial base stations, and a network in which TNs and NTNs coexist. These base stations and communication cells may belong to the same mobile communication network, public land mobile network (PLMN), mobile network operator (MNO), or mobile virtual network operator (MVNO), or may belong to different mobile communication networks, PLMNs, MNOs, or MVNOs. Hereinafter, mobile communication networks, PLMNs, MNOs, and MVNOs are collectively referred to as PLMNs.

[0016] 1 is a schematic diagram illustrating an overview of a wireless communication system 1 to which a communication control device according to this embodiment is applied. The wireless communication system 1 includes a 5G wireless communication system 11 that conforms to a fifth-generation mobile communication system (5G) that uses NR (New Radio) or 5G NR (Fifth Generation New Radio) as a radio access technology (RAT) and 5GC (Fifth Generation Core) as a core network (CN), a 4G wireless communication system 12 that conforms to a fourth-generation mobile communication system (4G) that uses LTE (Long Term Evolution) or LTE-Advanced as a radio access technology and EPC (Evolved Packet Core) as a core network, and a satellite communication system 13 that handles satellite communication via a communication satellite 131. Although not illustrated, the wireless communication system 1 may include a wireless communication system of a generation earlier than 4G, a wireless communication system of a generation later than 5G (e.g., 6G), or any wireless communication system that is not associated with a generation, such as Wi-Fi (registered trademark). Furthermore, the wireless communication system 1 does not necessarily have to include some or all of the 5G wireless communication system 11, the 4G wireless communication system 12, and the satellite communication system 13.

[0017] The 5G wireless communication system 11 includes communication devices 2A, 2B, 2C, and 2D (hereinafter sometimes collectively referred to as communication devices 2) such as smartphones that are installed on the ground and are also called UE (User Equipment), and multiple 5G base stations 111A, 111B, and 111C (hereinafter sometimes collectively referred to as 5G base stations 111) that can communicate via 5G NR. In 5G, the base station 111 is also called a gNodeB (gNB). The communication range or support area of each of the 5G base stations 111A, 111B, and 111C is called a cell, and is illustrated as 112A, 112B, and 112C, respectively (hereinafter sometimes collectively referred to as 5G cells 112).

[0018] The size of the 5G cell 112 of each 5G base station 111 is arbitrary, but typically ranges from a few meters to tens of kilometers in radius. Although there is no established definition, cells with a radius of a few meters to tens of meters are called femtocells, cells with a radius of tens to tens of meters are called picocells, cells with a radius of tens to hundreds of meters are called microcells, and cells with a radius of more than hundreds of meters are called macrocells. 5G often uses high-frequency radio waves such as millimeter waves, and because of their high line-propagation ability, radio waves can be blocked by obstacles, shortening the communication distance. For this reason, 5G tends to use smaller cells than 4G and earlier generations.

[0019] A communication device 2 can perform 5G communication if it is located within at least one of multiple 5G cells 112A, 112B, and 112C. In the illustrated example, a communication device 2B located within 5G cells 112A and 112B can communicate with both 5G base stations 111A and 111B via 5G NR. Furthermore, a communication device 2C located within 5G cell 112C can communicate with 5G base station 111C via 5G NR. Communication devices 2A and 2D are located outside all of the 5G cells 112A, 112B, and 112C and are therefore unable to communicate via 5G NR. 5G communication via 5G NR between each communication device 2 and each 5G base station 111 is managed by the 5GC, which is a core network. For example, the 5GC handles data transmission and reception between each 5G base station 111, data transmission and reception between EPC, a satellite communication system 13, and external networks such as the Internet, and mobility management of the communication device 2.

[0020] The 4G wireless communication system 12 includes multiple 4G base stations 121 (only one of which is shown in FIG. 1 ) that are installed on the ground and capable of communicating with the communication device 2 via LTE or LTE-Advanced. In 4G, the base station 121 is also called an eNodeB (eNB). Like each 5G base station 111, the coverage area or support area of each 4G base station 121 is also called a cell, and is illustrated as 122.

[0021] If the communication device 2 is located inside the 4G cell 122, it can perform 4G communication. In the illustrated example, communication devices 2A and 2B located inside the 4G cell 122 can communicate with the 4G base station 121 via LTE or LTE-Advanced. Communication devices 2C and 2D are located outside the 4G cell 122 and are therefore unable to communicate via LTE or LTE-Advanced. 4G communication between each communication device 2 and each 4G base station 121 via LTE or LTE-Advanced is managed by the EPC, which is a core network. For example, the EPC handles the exchange of data with each 4G base station 121, the exchange of data with external networks such as 5GC, the satellite communication system 13, and the Internet, and the mobility management of the communication device 2.

[0022] Focusing on each of the communicators 2A, 2B, 2C, and 2D, in the illustrated example, communicator 2A is capable of 4G communication with 4G base station 121, communicator 2B is capable of 5G communication with 5G base stations 111A and 111B and 4G communication with 4G base station 121, and communicator 2C is capable of 5G communication with 5G base station 111C. In cases where there are multiple base stations (111A, 111B, 121) with which communicator 2B can communicate, one base station determined to be optimal in terms of communication quality, etc., is selected under the management of the 5G communication center (5GC) and / or the EPC core network, and communication with communicator 2B is performed. Furthermore, communicator 2D is not capable of communication with any of the 5G base stations 111 and 4G base station 121, and therefore performs communication via satellite communication system 13, which will be described next.

[0023] The satellite communication system 13 is a wireless communication system that uses a communication satellite 131, which is a low-orbit satellite flying in space at an altitude of approximately 500 km to 700 km above the Earth's surface, as a non-terrestrial base station. Similar to the 5G base station 111 and the 4G base station 121, the communication range or support area of the communication satellite 131 is also called a cell and is illustrated as 132. In this way, the communication satellite 131, which is a non-terrestrial base station, provides the satellite communication cell 132, which is a non-terrestrial communication cell, to the ground. A terrestrial communication device 2 can perform satellite communication if it is located inside the satellite communication cell 132. Similar to the 5G base station 111 in the 5G wireless communication system 11 and the 4G base station 121 in the 4G wireless communication system 12, the communication satellite 131, which is a base station in the satellite communication system 13, can wirelessly communicate with the communication device 2 in the satellite communication cell 132 directly or indirectly via an aircraft or the like. The radio access technology that the communication satellite 131 uses for radio communication with the communication device 2 in the satellite communication cell 132 may be 5G NR, the same as the 5G base station 111, or LTE or LTE-Advanced, the same as the 4G base station 121, or any other radio access technology that can be used by the communication device 2. Therefore, the communication device 2 does not need to be provided with special functions or components for satellite communication.

[0024] The satellite communication system 13 includes a gateway 133 as a ground station installed on the ground and capable of communicating with a communication satellite 131. The gateway 133 includes a satellite antenna for communicating with the communication satellite 131, and is connected to a 5G base station 111 and a 4G base station 121 as terrestrial base stations that constitute a terrestrial network via their respective wireless access technologies, such as 5G NR or LTE, or other wired or wireless access technologies or interfaces. In this way, the gateway 133 connects the NTN formed by the communication satellite 131 and the TN formed by the terrestrial base stations 111 and 121 so that they can communicate with each other. When the communication satellite 131 performs 5G communication with the communication device 2 in the satellite communication cell 132 using 5G NR, the 5GC connected via the gateway 133 and the 5G base station 111 (or a 5G radio access network) in the TN is used as the core network, and when the communication satellite 131 performs 4G communication with the communication device 2 in the satellite communication cell 132 using LTE or LTE-Advanced, the EPC connected via the gateway 133 and the 4G base station 121 (or a 4G radio access network) in the TN is used as the core network. In this way, appropriate cooperation is achieved between different wireless communication systems such as 5G communication, 4G communication, and satellite communication via the gateway 133.

[0025] Satellite communication using a communication satellite 131 is primarily used to cover areas where terrestrial base stations such as 5G base station 111 and 4G base station 121 are not installed or are few in number. In the illustrated example, a communication device 2D located outside the communication cells of all terrestrial base stations communicates with the communication satellite 131. Meanwhile, communication devices 2A, 2B, and 2C that can communicate satisfactorily with any terrestrial base station are also within a satellite communication cell 132 and can therefore communicate with the communication satellite 131. However, by communicating with a terrestrial base station rather than the communication satellite 131 as a satellite base station, the limited communication resources (including power) of the communication satellite 131 are conserved for the communication device 2D and the like. The communication satellite 131 improves the quality of communication with the communication device 2D by directing communication radio waves toward the communication device 2D within the satellite communication cell 132 using beamforming.

[0026] The size of the satellite communication cell 132 of the communication satellite 131 as a satellite base station can be set arbitrarily depending on the number of beams emitted by the communication satellite 131; for example, a satellite communication cell 132 with a diameter of approximately 24 km can be formed by combining up to 2,800 beams. As shown in the figure, the satellite communication cell 132 is typically larger than a terrestrial communication cell such as the 5G cell 112 or 4G cell 122, and can include one or more 5G cells 112 and / or 4G cells 122 therein. In the above, a communication satellite 131 flying in space in a low earth orbit (LEO: Low Earth Orbit) at an altitude of about 500 km to 700 km above the earth's surface has been used as an example of a flying non-terrestrial base station, but a communication satellite flying in space in a higher orbit such as a geosynchronous equatorial orbit (GEO: Geosynchronous Equatorial Orbit) or an unmanned or manned aircraft flying in the atmosphere at a lower altitude (for example, about 20 km above the earth's surface) such as the stratosphere may also be used as a non-terrestrial base station in addition to or instead of the communication satellite 131.

[0027] As described above, the wireless communication system 1 according to this embodiment includes terrestrial networks (TN) 11, 12 capable of communicating with the communication devices 2 in the terrestrial communication cells 112, 122 provided on the ground by terrestrial base stations 111, 121 installed on the ground, and a non-terrestrial network (NTN) 13 capable of communicating with the communication devices 2 in the non-terrestrial communication cell 132 provided on the ground by an airborne non-terrestrial base station 131. The communication control device according to this embodiment controls the TN and / or the NTN.

[0028] FIG. 2 is a functional block diagram illustrating a communication control device 3 according to this embodiment. The communication control device 3 includes a movement information acquisition unit 31, an activity history information collection unit 32, a switching destination candidate detection unit 33, a cell information acquisition unit 34, a service quality information collection unit 35, a service provision availability determination unit 36, and a connection control unit 37. These functional blocks are implemented by the cooperation of hardware resources, such as a central processing unit (CPU) of a computer, memory, input devices, output devices, and peripheral devices connected to the computer, and software executed using these resources. Regardless of the type and location of the computer, each of the above functional blocks may be implemented by the hardware resources of a single computer or by a combination of hardware resources distributed across multiple computers. For example, some or all of the functional blocks of the communication control device 3 may be implemented in a distributed or centralized manner by computers and processors provided in a core network (not shown in FIG. 2 ) to which the communication device 2, the terrestrial base stations 111 and 121, the non-terrestrial base station 131, the gateway 133, the terrestrial base stations 111 and 121, and / or the non-terrestrial base station 131 are connected.

[0029] In the example of FIG. 2, the communication device 2 is connected to a first PLMN (shown as "PLMN1" in FIG. 2) as a first network. The first PLMN is a mobile communication network operated by a first communication carrier, which is an MNO or MVNO. For example, the first PLMN is configured by the above-mentioned 5G wireless communication system 11, 4G wireless communication system 12, satellite communication system 13, etc. In the example of FIG. 2, the first PLMN is configured by the 5G wireless communication system 11 or the 4G wireless communication system 12. One terrestrial communication cell 112, 122 (dashed line) formed by one terrestrial base station 111, 121 schematically or symbolically represents the first PLMN as a TN. In addition, the first PLMN in the example of FIG. 2 is a home network to which a user of the communication device 2 subscribes a communication service. Note that the first PLMN may also be a roaming network in which the communication device 2 can roam.

[0030] As will be described later, the communication device 2 is moving out of the first PLMN. To ensure continuous communication service for the communication device 2, the communication device 2 needs to connect to another PLMN before moving out of the first PLMN. Such networks that are candidates for switching destinations for the communication device 2 are hereinafter collectively referred to as second networks or second PLMNs. In the example of FIG. 2, three second PLMNs (shown as "PLMN2-1," "PLMN2-2," and "PLMN2-3," respectively, in FIG. 2) are schematically illustrated. Each second PLMN is a mobile communication network operated by a second communication carrier, which is an MNO or MVNO. The second communication carriers may be the same communication carrier or different communication carriers. Furthermore, each second communication carrier and the first communication carrier may be the same communication carrier or different communication carriers. In this embodiment, it is assumed that the first communication carrier and each second communication carrier are all different communication carriers.

[0031] Each second PLMN is configured by the aforementioned 5G wireless communication system 11, 4G wireless communication system 12, satellite communication system 13, etc. In the example of Fig. 2, the 5G wireless communication system 11 or the 4G wireless communication system 12 configures the 2-1 PLMN (PLMN2-1) and the 2-2 PLMN (PLMN2-2) as TNs, and the satellite communication system 13 configures the 2-3 PLMN (PLMN2-3) as NTN.

[0032] The second-first PLMN, labeled "NW Sharing," is a schematic or symbolic representation of a network that shares some of its network facilities with the first PLMN. Figure 3 illustrates the second-first PLMN. The second-first PLMN (PLMN2-1) shares all or part of its radio access network (RAN) with the first PLMN (PLMN1). However, core networks (CNs) including a unified data management (UDM) and a home subscriber server (HSS) that handle subscriber information are provided separately in the first and second-first PLMNs. This configuration is also called a multi-operator core network (MOCN). The communication device 2 before movement in Figure 2 is connected to the core network of the first PLMN via a shared RAN. When the communication device 2 after movement in Figure 2 connects to the second-first PLMN, it is connected to the core network of the second-first PLMN via a shared RAN. The first and second-first PLMNs can communicate with each other through the shared RAN. Additionally, the first PLMN and the second-1 PLMN may communicate with each other via the core network.

[0033] The second-2 PLMN, which is marked with "Roaming," schematically or symbolically represents a roaming network in which the communication device 2 can roam. FIG. 4 schematically shows the second-2 PLMN. The second-2 PLMN (PLMN2-2) has a radio access network (RAN) and core network (CN) separate from those of the first PLMN (PLMN1). The communication device 2 before movement in FIG. 2 is connected to the core network of the first PLMN via the RAN of the first PLMN. When the communication device 2 after movement in FIG. 2 is connected to the second-2 PLMN, it is connected to the core network of the 2-2 PLMN via the RAN of the 2-2 PLMN. The first PLMN and the second-2 PLMN can communicate with each other between their core networks.

[0034] The second-third PLMN, marked with "NTN," represents the NTN schematically or symbolically. The configuration when the second-third PLMN is a roaming network is the same as that shown in FIG. 4. That is, the second-third PLMN (PLMN2-3) has a radio access network (RAN) and core network (CN) separate from those of the first PLMN (PLMN1). The communication device 2 before movement in FIG. 2 is connected to the core network of the first PLMN via the RAN of the first PLMN. When the communication device 2 after movement in FIG. 2 is connected to the second-third PLMN, it is connected to the core network of the second-third PLMN via the RAN (communication satellite 131 or gateway 133) of the second-third PLMN. The first PLMN and the second-third PLMN can communicate with each other via their core networks.

[0035] The above classifications such as "NW Sharing," "Roaming," and "NTN" are not exclusive, and for example, the second PLMN may be an NTN (NTN) that is a roaming network (Roaming) that shares some of the network facilities with the first PLMN (NW Sharing). In this embodiment, all second PLMNs are considered to be roaming networks, but the second PLMNs may also be home networks.

[0036] The movement information acquisition unit 31 acquires movement information related to the movement of the communication device 2. The movement information includes at least one of the movement route of the communication device 2, the arrival time of the communication device 2 at each position on the movement route, the traffic congestion situation on the movement route, the movement speed of the communication device 2, the movement direction of the communication device 2, and the current position of the communication device 2. Some or all of this movement information can be acquired from the communication device 2 itself. For example, the movement route, the arrival time at each position on the movement route, and the traffic congestion situation on the movement route can be acquired from a map application or a navigation application installed in the communication device 2. In addition, the movement speed, movement direction, and current position can be acquired from a positioning module such as a GPS module installed in the communication device 2.

[0037] The movement information acquisition unit 31 may estimate some or all of the movement information of the communication device 2 based on the activity history information collected by the activity history information collection unit 32. The activity history information collection unit 32 collects activity history information of one or more specific or unspecified communication devices 2. The activity history information collected by the activity history information collection unit 32 is also used by the switching destination candidate detection unit 33, which will be described later.

[0038] For example, the NWDAF (Network Data Analytics Function) and LMF (Location Management Function), which are introduced in 5GC as the 5G core network CN, can be used as the activity history information collector 32. The NWDAF is responsible for collecting and analyzing data on a network, including 5G. Specifically, the NWDAF collects and stores activity history information (including history information on the base stations to which the communication devices 2 are connected and the locations of the communication devices 2) regarding various activities performed on the network by a large number of communication devices 2 connected to the network, and uses the analysis results for, for example, traffic control on the network. The LMF manages the physical locations of a large number of communication devices 2 on a network, including 5G. It is anticipated that functions similar to the NWDAF and / or LMF may be provided under different names in other wireless communication systems, including wireless communication systems of generations after 5G. In this embodiment, such similar functions may be used instead of or in addition to the NWDAF and / or LMF.

[0039] Additionally, a server used by a service provider that provides map services, navigation services, location tracking services, etc. to a large number of communication devices 2 connected to a network can also be used as the activity history information collection unit 32. These servers can also collect activity history information (including history information related to the locations of the communication devices 2) related to various activities performed by a large number of communication devices 2 connected to the network in relation to the services provided.

[0040] From the NWDAF, LMF, and service provider servers acting as activity history information collection units 32, statistical information (including statistical information on the base stations to which they are connected) and / or history information on the physical locations of an unspecified number of communication devices 2 connected to the network can be obtained.

[0041] Based on the activity history information (including network and / or physical congestion information and traffic jam information) of these unspecified number of communication devices 2 for each time period, the movement information acquisition unit 31 can accurately estimate the location and movement state at current or future times of the communication devices 2 that are the subject of communication control by the communication control device 3, and the switching destination candidate detection unit 33 can reliably detect the second PLMN (PLMN2-1, PLMN2-2, PLMN2-3) to which the communication device 2 will move.

[0042] For example, if, in the current or future time period when the movement information acquisition unit 31 estimates the movement information of the communication device 2, a specific area among a plurality of areas where the communication device 2 may be located has a significantly large amount of past communication traffic or a significantly large number of communication devices 2, it can be estimated that the area is likely to contain the communication device 2 to be estimated. Similarly, in the current or future time period when the switching destination candidate detection unit 33 detects the second PLMN, if a specific communication cell among a plurality of communication cells to which the communication device 2 may be connected has a significantly large amount of past communication traffic or a significantly large number of communication devices 2, it can detect the network to which the communication cell belongs as the second PLMN.

[0043] From the NWDAF, LMF, and service provider server serving as the activity history information collection unit 32, it is possible to acquire not only an unspecified number of communication devices 2, but also statistical information (including statistical information on the base station to which the communication device 2 is connected) on the network of the communication device 2 itself that is the subject of estimation or communication control, and / or history information on the physical location. Based on the activity history information of the communication device 2 itself for each time period, the movement information acquisition unit 31 can estimate with high accuracy the location and movement state of the communication device 2 at the current or future time, and the switching destination candidate detection unit 33 can detect an appropriate second PLMN by referring to the history of communication cells to which the communication device 2 has previously connected.

[0044] For example, if the frequency with which the communication device 2 was in a particular area is high during the current or future time period when the movement information acquisition unit 31 estimates the movement information of the communication device 2, it can be estimated that there is an extremely high possibility that the communication device 2 to be estimated is in that area. Similarly, if the frequency with which the communication device 2 was connected to a particular communication cell is high during the current or future time period when the switching destination candidate detection unit 33 detects a second PLMN, it can preferentially detect the network to which that communication cell belongs as the second PLMN.

[0045] Furthermore, in addition to or instead of the activity history information for a different day in the past as described above, the movement information acquisition unit 31 and / or the switching destination candidate detection unit 33 may use activity history information of the communication device 2 itself immediately before (e.g., within one hour) estimating the movement information of the communication device 2 and / or immediately before (e.g., within one hour) detecting the second PLMN. For example, if the communication device 2 was moving in a specific direction within a specific area 30 minutes before the movement information acquisition unit 31 estimated the movement information of the communication device 2, it can be estimated that there is an extremely high possibility that the communication device 2 to be estimated is in that area or a nearby area that can be moved from that area in that direction within 30 minutes. Similarly, if the communication device 2 was connected to a specific communication cell 30 minutes before the switching destination candidate detection unit 33 detected the second PLMN, it can preferentially detect a network to which a communication cell overlaps and / or is adjacent to that communication cell as the second PLMN.

[0046] The switching destination candidate detection unit 33 detects one or more second PLMNs that are candidates for switching destinations of the communication device 2 connected to the first PLMN. In the example of Fig. 2, the switching destination candidate detection unit 33 detects multiple second PLMNs (PLMN2-1, PLMN2-2, PLMN2-3) that are candidates for switching destinations of the communication device 2, based on various types of cell information such as movement information acquired by the movement information acquisition unit 31, activity history information collected by the activity history information collection unit 32, and cell layout information acquired by the cell information acquisition unit 34.

[0047] The cell information acquisition unit 34 acquires cell layout information regarding the layout of communication cells of one or more second PLMNs detected by the handover destination candidate detection unit 33. The cell information acquisition unit 34 acquires the terrestrial layout of the communication cells of each of the multiple second PLMNs (PLMN2-1, PLMN2-2, PLMN2-3) as shown in Fig. 2, for example, from each base station that provides each communication cell or from a core network CN that collectively manages information related to each communication cell. This cell layout information not only enables the recognition of the center position and shape and size of each communication cell's coverage area (communication range), but also the presence or absence of communication cells in each terrestrial area, the type of communication cell (terrestrial communication cell or non-terrestrial communication cell), the density of communication cells, the continuity or overlap of communication cells, the distance from the center position or edge of the communication cell, etc. The switching destination candidate detection unit 33 detects a second PLMN that is a candidate for the switching destination of the communication device 2 by referring to this cell allocation information together with other information (such as the movement information of the communication device 2 acquired by the movement information acquisition unit 31).

[0048] The above has individually described various types of information that the switching destination candidate detection unit 33 can refer to when detecting second PLMNs. In practice, the switching destination candidate detection unit 33 comprehensively takes into consideration or considers this information (movement information acquired by the movement information acquisition unit 31, activity history information collected by the activity history information collection unit 32, cell placement information acquired by the cell information acquisition unit 34, etc.) and then detects one or more second PLMNs that are deemed optimal under certain criteria. For this purpose, the switching destination candidate detection unit 33 may be configured using artificial intelligence that has undergone machine learning using comprehensive training data or learning data.

[0049] The service quality information collection unit 35 collects service quality information in one or more second PLMNs (PLMN2-1, PLMN2-2, PLMN2-3) detected by the handover destination candidate detection unit 33. The service quality information collection unit 35 is preferably provided in the radio access network (RAN) or core network (such as the NWDAF in FIG. 6) of the second PLMN itself. Examples of the service quality information collected by the service quality information collection unit 35 include information on the service quality in the second PLMN, the area (coverage range) of the second PLMN, the service provision method in the second PLMN, and the handover method from the first PLMN to the second PLMN.

[0050] 5 shows four specific examples of service quality information collected by the service quality information collection unit 35. In the example of this figure, in response to an inquiry from the first PLMN to the second PLMN shown in the left column, service quality information in the second PLMN shown in the right column is shared from the second PLMN to the first PLMN.

[0051] The first service quality information relates to the service quality in the second PLMN. First, the first PLMN notifies the second PLMN of the content and type of service being received by the communication device 2 connected to the first PLMN as an inquiry to the second PLMN. In response to this notification, the second PLMN directly or indirectly shares with the first PLMN its assumption of the quality of service (QoS) that it will provide to the communication device 2 when providing the service.

[0052] When the second PLMN is a 5G network, the information related to QoS in the second PLMN includes various QoS parameters specified by a 5QI (5G QoS Identifier), etc. Examples of the QoS parameters include whether or not a bit rate is guaranteed, a priority level, a packet delay budget, a packet error rate, an ARP (Allocation and Retention Priority), a Guaranteed Flow Bit Rate (GFBR), a Maximum Flow Bit Rate (MFBR), an Aggregate Maximum Bit Rate (AMBR), and a maximum packet loss rate.

[0053] 5QI defines recommended combinations of the various QoS parameters mentioned above for typical use cases. Use cases are broadly categorized into three resource types: non-guaranteed bitrate (Non-GBR), guaranteed bitrate (GBR), and delay-critical GBR. Each resource type is subdivided into multiple different QoS levels, and a recommended combination of QoS parameters is defined for each QoS level, with a unique 5QI set to specify that combination. Among these three resource types, the required QoS level generally increases in the order of Non-GBR, GBR, and delay-critical GBR.

[0054] The second service quality information relates to the area (coverage range) of the second PLMN. First, the first PLMN notifies the second PLMN of geographical information such as the current location of the communication device 2 connected to the first PLMN as an inquiry to the second PLMN. In response to this notification, the second PLMN directly or indirectly shares with the first PLMN information such as its own cell, PLMN, tracking area (location registration area) where it provides service to the communication device 2.

[0055] The third service quality information relates to a service provision method in the second PLMN. In response to an inquiry about the service provision method from the first PLMN, the second PLMN directly or indirectly shares with the first PLMN information such as the network slice used to provide the service to the communication device 2 and billing information for the service provision.

[0056] The fourth type of service quality information relates to a switching method from the first PLMN to the second PLMN. In response to an inquiry from the first PLMN about the switching method, the second PLMN directly or indirectly shares with the first PLMN switching methods such as handover and redirection, and supporting information such as neighboring cells and frequency bands used or referenced during the switching.

[0057] The above-described service quality information collected by the service quality information collection unit 35 preferably corresponds to the actual communication mode of the communication device 2 in the second PLMN. For example, in the 2-1 PLMN in Fig. 3, the network shared communication quality information in communication using the network with the first PLMN is preferably collected by the service quality information collection unit 35 as service quality information distinguished from service quality information in communication not using the network shared (not shown). Also, in the 2-2 PLMN in Fig. 4, the roaming communication quality information in communication using roaming is preferably collected by the service quality information collection unit 35 as service quality information distinguished from service quality information in communication not using roaming (not shown).

[0058] The query and response shown in Figure 5 may be performed via any interface or communication path between the first PLMN and the second PLMN. For example, in the case of a shared network as shown in Figure 3, the query and response shown in Figure 5 may be performed via shared network equipment such as a RAN. Furthermore, the query and response shown in Figure 5 may be performed between the core networks of the first PLMN and the second PLMN, including the case of a shared network as shown in Figure 3 and the case of roaming as shown in Figure 4.

[0059] The query and response shown in Figure 5 may be performed through the NEF in 5G. Figure 6 shows a schematic example of a procedure when the query and response shown in Figure 5 are performed by an Application Function (AF) outside 5GC and a Network Exposure Function (NEF) and / or NWDAF within 5GC. AF is a general term for external functions realized by applications outside 5GC. The NEF provides the AF with an Application Programming Interface (API) for various functions within 5GC, including the NWDAF.

[0060] In the illustrated example, a first PLMN (PLMN1) as a query source functions as an AF and requests service quality information of a second PLMN (PLMN2) as a query destination from the NEF of the second PLMN using "Analytics Exposure," one of the NEF's APIs (step "1" in the illustration). At this time, the AF (first PLMN) or the NEF may add identification information to the query indicating that the query is from a PLMN different from the second PLMN. The NEF transmits the request for service quality information from the AF to the NWDAF of the second PLMN using the interface "Analytics Subscription" (step "2" in the illustration). At this time, the NEF may generate a request for service quality information based on the information provided by the AF in step "1" in the illustration, based on the mapping in step "0" in the illustration, and transmit the request to the NWDAF in step "2" in the illustration.

[0061] The NWDAF, functioning as the service quality information collector 35, generates or collects the service quality information (corresponding to the right column in FIG. 5) in the second PLMN requested in illustrated steps "1" and / or "2" (corresponding to the left column in FIG. 5). This service quality information in the second PLMN is provided from the NWDAF to the NEF in illustrated step "3" and further provided from the NEF to the AF (first PLMN) in illustrated step "4".

[0062] In order to promptly provide the above-described service quality information in the second PLMN in response to an inquiry from the first PLMN, the service quality information collecting unit 35 preferably periodically collects the service quality information in advance, regardless of whether or not an inquiry from the first PLMN has been received. Furthermore, the service quality information collecting unit 35 may periodically share the service quality information in the second PLMN with the first PLMN even when no inquiry from the first PLMN has been received. This often eliminates the need for the first PLMN to inquire about service quality information from the second PLMN, allowing for prompt transition to subsequent processing in the service provision availability determining unit 36 and the connection control unit 37, which will be described later. In this manner, the service quality information collecting unit 35 preferably collects the service quality information in the second PLMN in advance before the connection control unit 37 starts the procedure for switching the communication device 2 from the first PLMN to the second PLMN. Furthermore, the service quality information in the second PLMN collected by the service quality information collecting unit 35 is preferably shared between the first PLMN and the second PLMN in advance before the connection control unit 37 starts the procedure for switching the communication device 2 from the first PLMN to the second PLMN.

[0063] The service provision availability determination unit 36 determines, based on communication between a first PLMN from which the communication device 2 is switched and a second PLMN to which the communication device 2 is switched, whether the second PLMN can continuously provide the communication device 2 with the service that the first PLMN is providing to the communication device 2. Specifically, the service provision availability determination unit 36 determines, based on service quality information collected by the service quality information collection unit 35 and shared between the first PLMN and each second PLMN (PLMN2-1, PLMN2-2, PLMN2-3) via any of the interfaces and communication paths exemplified with reference to Figures 3 to 6, whether each second PLMN can continuously provide the service to the communication device 2. The service provision availability determination unit 36 determines, based on a comprehensive consideration of various types of service quality information in the right column in Figure 5, whether each second PLMN can continuously provide the service to the communication device 2.

[0064] The service provision determination unit 36 may compare the service quality information of all second PLMNs that are candidates for the communication device 2 to switch to, and determine the second PLMN that provides the highest service quality among them. Furthermore, when the communication device 2 remains within the coverage area of the first PLMN, the service quality currently provided to the communication device 2 by the first PLMN may be compared with the service quality information of all second PLMNs that are candidates for the communication device 2 to switch to, and determine the PLMN that provides the highest service quality among them. If it is determined that the service quality of the first PLMN is higher than that of any of the second PLMNs, the connection control unit 37 (described later) does not switch the communication device 2 to the second PLMN, and the communication device 2 maintains its connection to the first PLMN.

[0065] The service provision availability determination unit 36 may determine whether the second PLMN can continuously provide service to the communication device 2 based on service quality information collected by the service quality information collection unit 35 and shared from a second PLMN that is a candidate for switching during a switching procedure such as handover or redirection of the communication device 2 from the first PLMN by the connection control unit 37. Also, the service provision availability determination unit 36 may determine whether the second PLMN can continuously provide service to the communication device 2 based on service quality information collected by the service quality information collection unit 35 and shared from the second PLMN in response to an inquiry from the first PLMN as shown in Figures 5 and 6.

[0066] For the 2-1 PLMN in Fig. 3 that shares part of the network facilities with the 1 PLMN, the service provision availability determination unit 36 determines whether the 2-1 PLMN can continuously provide service to the communication device 2 based on network shared communication quality information shared between the 1 PLMN and the 2-1 PLMN. Also, for the 2-2 PLMN in Fig. 4 that is a roaming network, the service provision availability determination unit 36 determines whether the 2-2 PLMN can continuously provide service to the communication device 2 based on roaming communication quality information shared between the 1 PLMN and the 2-2 PLMN.

[0067] When the service provision availability determination unit 36 determines that the second PLMN can continuously provide service to the communication device 2, the connection control unit 37 switches the connection destination of the communication device 2 from the first PLMN to the second PLMN. When there are multiple second PLMNs that are candidates for the switching destination of the communication device 2 (e.g., PLMN 2-1, PLMN 2-2, PLMN 2-3 in FIG. 2), the connection control unit 37 switches the connection destination of the communication device 2 to one of the second PLMNs determined to be able to continuously provide service to the communication device 2. For example, the connection control unit 37 switches the connection destination of the communication device 2 to the second PLMN determined by the service provision availability determination unit 36 to achieve the highest service quality among the multiple second PLMNs. When switching the connection destination of the communication device 2 to the roaming network 2-2 PLMN in FIG. 4, the connection control unit 37 causes the communication device 2 to roam to the 2-2 PLMN.

[0068] According to this embodiment, when the service provision feasibility determination unit 36 determines that the second PLMN can continuously provide the service provided by the first PLMN to the communication device 2, the connection destination of the communication device 2 is switched from the first PLMN to the second PLMN by the connection control unit 37, thereby improving the continuity of services in different PLMNs.

[0069] The present disclosure has been described above based on the embodiments. Various modifications are possible to the combinations of the components and processes in the exemplary embodiments, and it will be obvious to those skilled in the art that such modifications are included within the scope of the present disclosure.

[0070] 2 illustrates the switching of PLMNs for a mobile communication device 2, but the present disclosure can also be applied to the switching of PLMNs for a stationary communication device 2 and / or a communication device 2 that remains within the coverage area of a first PLMN. If the service quality in the first PLMN to which the communication device 2 is connected deteriorates due to congestion or other reasons, the connection control unit 37 can switch the communication device 2 to a second PLMN whose coverage area overlaps with that of the first PLMN. Because the service provision availability determination unit 36 has determined that the second PLMN to which the communication device 2 is connected can continuously provide service to the communication device 2, the continuity of service in different PLMNs can be improved.

[0071] The configuration, operation, and function of each device and method described in the embodiments can be realized by hardware resources, software resources, or a combination of hardware and software resources. Examples of hardware resources include processors, ROMs, RAMs, and various integrated circuits. Examples of software resources include operating systems, applications, and other programs.

[0072] This disclosure may be expressed in the following terms:

[0073] Item 1: detecting, by a switching destination candidate detection unit, a second network that is a switching destination candidate for a communication device connected to the first network; determining, by a service provision availability determination unit, whether or not the second network can continuously provide the communication device with the service currently being provided by the first network to the communication device, based on communication between the first network and the second network; when it is determined by the connection control unit that the second network can continuously provide the service to the communication device, switching the connection destination of the communication device from the first network to the second network; A communication control device comprising at least one processor that executes the above. Item 2: the at least one processor further performs, by a service quality information collection unit, collecting service quality information in the second network; the service provision availability determination unit determines whether the second network can continuously provide the service to the communication device based on the service quality information shared between the first network and the second network. Item 1. The communication control device according to item 1. Item 3: the service quality information collection unit is provided in the second network, the service provision availability determination unit determines whether the second network can continuously provide the service to the communication device based on the service quality information shared from the second network in a switching procedure from the first network of the communication device by the connection control unit. Item 2. A communication control device. Item 4: the service quality information collection unit is provided in the second network, the service provision availability determination unit determines whether the second network can continuously provide the service to the communication device based on the service quality information shared from the second network in response to an inquiry from the first network. Item 4. The communication control device according to item 2 or 3. Item 5: 5. The communication control device according to item 4, wherein the inquiry is made via a Network Exposure Function (NEF). Item 6: A communication control device described in any of items 2 to 5, wherein the service quality information in the second network includes at least one of information regarding service quality, area, service provision method, and switching method from the first network to the second network. Item 7: 7. The communication control device according to any one of items 2 to 6, wherein the service quality information collection unit collects the service quality information according to a communication mode in the second network. Item 8: the service quality information collecting unit collects roaming communication quality information in roaming communication as the service quality information according to the communication mode in the second network; the switching destination candidate detection unit detects the second network, which is a roaming network that is a switching destination candidate of the communication device connected to the first network, which is a home network; the service provision availability determination unit determines whether the second network can continuously provide the service to the communication device based on the roaming communication quality information shared between the first network and the second network; the connection control unit, when it is determined that the second network can continuously provide the service to the communication device, causes the communication device to roam to the second network; Item 7. The communication control device according to item 7. Item 9: the service quality information collecting unit collects, as the service quality information according to the communication mode in the second network, network shared communication quality information in communication using a part of network equipment of the first network and the second network; the service provision availability determination unit determines whether the second network can continuously provide the service to the communication device based on the network shared communication quality information shared between the first network and the second network. Item 9. The communication control device according to item 7 or 8. Item 10: A communication control device described in any of items 2 to 9, wherein the service quality information collection unit collects the service quality information in the second network in advance before the connection control unit starts a switching procedure from the first network of the communication device. Item 11: Item 11. A communication control device according to item 10, wherein the service quality information is shared in advance between the first network and the second network before the connection control unit initiates a switching procedure from the first network of the communication device. Item 12: the at least one processor further executes acquiring, by a movement information acquiring unit, movement information related to movement of the communication device; the switching destination candidate detection unit detects the second network as a destination of the communication device; 12. A communication control device according to any one of items 1 to 11. Item 13: 13. The communication control device according to any one of items 1 to 12, wherein a first communication carrier that operates the first network and a second communication carrier that operates the second network are different from each other. Item 14: one of the first network and the second network is a home network to which a user of the communication device subscribes for a communication service; the other of the first network and the second network is a roaming network in which the communication device can roam; 14. A communication control device according to any one of items 1 to 13. Item 15: 14. The communication control device according to any one of items 1 to 13, wherein the first network and the second network are roaming networks in which the communication device can roam. Item 16: 16. The communication control device according to any one of items 1 to 15, wherein the first network and the second network share a portion of network equipment. Item 17: the switching destination candidate detection unit detects a plurality of the second networks; the service provision availability determination unit determines whether the second networks can continuously provide the service to the communication device; the connection control unit switches the connection destination of the communication device to any one of the second networks determined to be able to continuously provide the service to the communication device. 17. A communication control device according to any one of items 1 to 16. Item 18: Detecting a second network that is a candidate for a switching destination of a communication device connected to the first network; determining, based on communication between the first network and the second network, whether the second network can continue to provide the communication device with the service that the first network provides to the communication device; If it is determined that the second network can continuously provide the service to the communication device, switching the connection destination of the communication device from the first network to the second network; A communication control method comprising: Item 19: Detecting a second network that is a candidate for a switching destination of a communication device connected to the first network; determining, based on communication between the first network and the second network, whether the second network can continue to provide the communication device with the service that the first network provides to the communication device; If it is determined that the second network can continuously provide the service to the communication device, switching the connection destination of the communication device from the first network to the second network; A storage medium that stores a communication control program that causes a computer to execute the above. [Industrial Applicability]

[0074] The present disclosure relates to improving continuity of services across different networks. [Explanation of symbols]

[0075] 1 wireless communication system, 2 communication device, 3 communication control device, 11 5G wireless communication system, 12 4G wireless communication system, 13 satellite communication system, 31 movement information acquisition unit, 32 activity history information collection unit, 33 switching destination candidate detection unit, 34 cell information acquisition unit, 35 service quality information collection unit, 36 service provision availability determination unit, 37 connection control unit, 111 5G base station, 112 5G cell, 121 4G base station, 122 4G cell, 131 communication satellite, 132 satellite communication cell, 133 gateway.

Claims

1. detecting, by a switching destination candidate detection unit, a second network that is a switching destination candidate for a communication device connected to the first network; determining, by a service provision availability determination unit, whether or not the second network can continuously provide the communication device with the service currently being provided to the communication device by the first network, based on communication between the first network and the second network; when it is determined by the connection control unit that the second network can continuously provide the service to the communication device, switching the connection destination of the communication device from the first network to the second network; collecting service quality information in the second network by a service quality information collecting unit; at least one processor executing the service provision availability determination unit determines whether the second network can continuously provide the service to the communication device based on the service quality information shared between the first network and the second network; the service quality information collecting unit collects the service quality information according to a communication mode in the second network; the service quality information collecting unit collects roaming communication quality information in roaming communication as the service quality information according to the communication mode in the second network; the switching destination candidate detection unit detects the second network, which is a roaming network that is a switching destination candidate of the communication device connected to the first network, which is a home network; the service provision availability determination unit determines whether the second network can continuously provide the service to the communication device based on the roaming communication quality information shared between the first network and the second network; the connection control unit, when it is determined that the second network can continuously provide the service to the communication device, causes the communication device to roam to the second network; the service quality information collecting unit collects, as the service quality information according to the communication mode in the second network, network shared communication quality information in communication using a part of network equipment of the first network and the second network; the service provision availability determination unit determines whether the second network can continuously provide the service to the communication device based on the network shared communication quality information shared between the first network and the second network; The service quality information collecting unit collects the roaming communication quality information and the network shared communication quality information as the service quality information that is distinguished from each other.

2. the service quality information collection unit is provided in the second network, the service provision availability determination unit determines whether the second network can continuously provide the service to the communication device based on the service quality information shared from the second network in a switching procedure from the first network of the communication device by the connection control unit. The communication control device according to claim 1 .

3. the service quality information collection unit is provided in the second network, the service provision availability determination unit determines whether the second network can continuously provide the service to the communication device based on the service quality information shared from the second network in response to an inquiry from the first network. The communication control device according to claim 1 .

4. The communication control device according to claim 3 , wherein the inquiry is made through a Network Exposure Function (NEF).

5. The communication control device according to claim 1 , wherein the service quality information in the second network includes at least one of information on service quality, area, service providing method, and switching method from the first network to the second network.

6. The communication control device according to claim 1 , wherein the service quality information collection unit collects the service quality information in the second network in advance before the connection control unit starts a procedure for switching the communication device from the first network.

7. The communication control device according to claim 6 , wherein the service quality information is shared in advance between the first network and the second network before the connection control unit starts a procedure for switching the communication device from the first network.

8. the at least one processor further executes acquiring, by a movement information acquiring unit, movement information related to movement of the communication device; the switching destination candidate detection unit detects the second network as a destination of the communication device; The communication control device according to claim 1 .

9. The communication control device according to claim 1 , wherein a first communication carrier that operates the first network and a second communication carrier that operates the second network are different from each other.

10. the switching destination candidate detection unit detects a plurality of the second networks; the service provision availability determination unit determines whether the second networks can continuously provide the service to the communication device; the connection control unit switches the connection destination of the communication device to any one of the second networks determined to be able to continuously provide the service to the communication device. The communication control device according to claim 1 .

11. Detecting a second network that is a candidate for a switching destination of a communication device connected to the first network; determining, based on communication between the first network and the second network, whether the second network can continue to provide the communication device with the service that the first network provides to the communication device; If it is determined that the second network can continuously provide the service to the communication device, switching the connection destination of the communication device from the first network to the second network; collecting quality of service information in the second network; Equipped with determining whether the second network can continuously provide the service to the communication device based on the service quality information shared between the first network and the second network; The collecting includes collecting the service quality information according to a communication mode in the second network, collecting includes collecting roaming communication quality information in roaming communication as the service quality information according to the communication mode in the second network; The detecting includes detecting the second network, which is a roaming network that is a candidate for a switching destination of the communication device connected to the first network, which is a home network; The determining step includes determining whether the second network can continuously provide the service to the communication device based on the roaming communication quality information shared between the first network and the second network; The switching includes roaming the communication device to the second network if it is determined that the second network can continue to provide the service to the communication device; the collecting includes collecting network shared communication quality information in communication using a part of network equipment of the first network and the second network as the service quality information according to the communication mode in the second network; The determining step includes determining whether the second network can continuously provide the service to the communication device based on the network shared communication quality information shared between the first network and the second network; The communication control method includes collecting the roaming communication quality information and the network shared communication quality information as the service quality information that are distinguished from each other.

12. Detecting a second network that is a candidate for a switching destination of a communication device connected to the first network; determining, based on communication between the first network and the second network, whether the second network can continue to provide the communication device with the service that the first network provides to the communication device; If it is determined that the second network can continuously provide the service to the communication device, switching the connection destination of the communication device from the first network to the second network; collecting quality of service information in the second network; A communication control program that causes a computer to execute the above is stored, determining whether the second network can continuously provide the service to the communication device based on the service quality information shared between the first network and the second network; The collecting includes collecting the service quality information according to a communication mode in the second network, collecting includes collecting roaming communication quality information in roaming communication as the service quality information according to the communication mode in the second network; The detecting includes detecting the second network, which is a roaming network that is a candidate for a switching destination of the communication device connected to the first network, which is a home network; The determining step includes determining whether the second network can continuously provide the service to the communication device based on the roaming communication quality information shared between the first network and the second network; The switching includes roaming the communication device to the second network if it is determined that the second network can continue to provide the service to the communication device; the collecting includes collecting network shared communication quality information in communication using a part of network equipment of the first network and the second network as the service quality information according to the communication mode in the second network; The determining step includes determining whether the second network can continuously provide the service to the communication device based on the network shared communication quality information shared between the first network and the second network; A storage medium storing the communication control program executed by the computer, in which the collecting includes collecting the roaming communication quality information and the network shared communication quality information as the service quality information that are distinguished from each other.

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