JP6847995B2 - Mobile communication systems, mobility control methods and programs - Google Patents

Description

The present invention relates to mobility control in a mobile communication system including a plurality of base stations having different wireless communication methods with a terminal device.

The first base station (eNodeB) using the 4th generation LTE (Long Term Evolution) wireless communication system (hereinafter, also referred to as “LTE system”) can handle one or more frequency bands. The second base station (gNodeB) that uses a newer generation (for example, the fifth generation; hereinafter also referred to as “NG”) wireless communication system (hereinafter, also referred to as “NR system”) is one of the first base stations or Multiple frequencies can be used as anchors. Hereinafter, an LTE base station that is not used as an anchor is also referred to as a “non-anchor LTE base station”, and a frequency band that is not used as an anchor is also referred to as a “non-anchor frequency band”.

An NSA (Non-Standalone) type NG-compatible mobile communication system in which an LTE first base station and an NG second base station are mixed in a common area is known (see, for example, Non-Patent Document 1). In this NSA mobile communication system, the LTE core network and the NR system are used via the LTE first base station (anchor LTE base station) without newly establishing an NG core network (hereinafter, also referred to as “NGC”). Control data can be communicated with the second base station, and the terminal device (also referred to as "user device (UE)") is connected to the first LTE base station and the second NR system. It is possible to connect to a base station and communicate user data by the LTE method and the NR method via each base station.

3GPP TR 38.801 V14.0.0 (2017-03), Technical Specification Group Radio Access Network; Study on new radio access technology: Radio access architecture and interfaces (Release 14)

In the above-mentioned NSA mobile communication system, a plurality of first base stations (eNodeB) serving as anchor LTE base stations and non-anchor LTE base stations coexist in a common area, and terminal devices that can be connected to the second base station are non-anchor LTE. When located in the area of a base station, the terminal device cannot be connected to the second base station. In this case, the first base station operating as a non-anchor LTE base station (including the first base station using the non-anchor frequency band as the frequency band capable of wireless communication) is the first base station operating as the anchor LTE base station (including the first base station using the non-anchor frequency band). It is necessary to detect (including a first base station that uses an anchor frequency band as a frequency band capable of wireless communication) and connect a terminal device that can be connected to the second base station to the anchor LTE base station.
The first base station operating as a non-anchor LTE base station needs a means to know the first base station operating as an anchor LTE base station mixed in a common area and register its own station as a non-anchor LTE base station. However, conventionally, there is only a method of manually registering in advance by overlapping simulation of areas.

The mobile communication system according to one aspect of the present invention is a terminal using a first base station that wirelessly communicates with a terminal device using a first wireless communication method and a second wireless communication method different from the first wireless communication method. This is a mobile communication system in which a second base station that wirelessly communicates with the device is provided in a common area. In the mobile communication system, a plurality of the first base stations are provided in the common area, and among the plurality of first base stations, some first base stations are located between the core network and the second base station. The other first base station is a non-anchor type first base station that does not relay control data between the core network and the second base station. Is. When the other first base station detects a cell of the anchor type first base station that overlaps with the cell of the own station, the other first base station sets the own station as the non-anchor type first base station.

In the mobile communication system, the anchor type first base is based on the information acquired by the direct communication between the base stations or the communication between the core network and the base station and the measurement report (MR) received from the terminal device. The cell of the station may be detected.

In the mobile communication system, when the non-anchor type first base station is a terminal device connected to its own station, the terminal device can be connected to the second base station by the second wireless communication method. The terminal device may be controlled so as to preferentially hand over the terminal device from the non-anchor type first base station to the anchor type first base station.
In the mobile communication system, the overlapping area of the cell of the second base station and the cell of the anchor type first base station in the unconnected mode in the terminal device that can be connected to the second base station by the second wireless communication method. When located in, the anchor-type first base station may be preferentially connected by the terminal device.
In the mobile communication system, when the terminal device connected to the own station is located at the end of the cell of the second base station, the anchor type first base station attaches the terminal device to the anchor type first base station. It may be controlled so that one base station preferentially hands over to the non-anchor type first base station.
In the mobile communication system, the anchor type first base station and the non-anchor type first base station are used when the terminal device connected to the own station is located outside the cell of the second base station. It may be controlled so that the cell of the first base station is handed over according to the priority set.

In the mobile communication system, the anchor type first base station and the non-anchor type first base station are the anchor type first base station when the terminal device connected to the own station is in the unconnected mode. The unconnected mode mobility control information (IMMCI) for preferentially connecting to the station may be transmitted to the terminal device. Here, the valid time of the unconnected mode mobility control information (IMMCI) may be longer than the update cycle of the tracking area by the terminal device.

In the mobile communication system, it is determined whether or not the terminal device is a terminal device that can be connected to the second base station based on at least one of the terminal identification information and the terminal capability information stored in the terminal device. You may.
In the mobile communication system, the measurement of the received signal for the cell of the second base station by the terminal device is performed when the cell is connected to the anchor type first base station, and the anchor type first base station is connected to the cell. It may not be done when not connected to.

In the mobile communication system, the anchor type first base station, the non-anchor type first base station, and the second base station may be base stations of the same vendor, respectively.
In the mobile communication system, the vendors of the anchor type first base station and the second base station and the vendors of the non-anchor type first base station may be different from each other.

In the mobile communication system, the frequency bands used for the plurality of first base stations and the second base station may be different from each other.
In the mobile communication system, data communication by ENDC (Eutra NR Dual Connectivity) may be performed between each of the anchor type first base station and the second base station and the terminal device.
In the mobile communication system, data communication by carrier aggregation may be performed between each of the anchor type first base station and the non-anchor type first base station and the terminal device.
In the mobile communication system, a plurality of the non-anchor type first base stations may be provided, and data communication by carrier aggregation may be performed between each of the non-anchor type first base stations and the terminal device.

In the mobile communication system, the first wireless communication system is a wireless communication system compliant with the fourth generation LTE, and the second wireless communication system is a fifth generation or later newer than the fourth generation LTE. It may be a next-generation wireless communication system.

The base station according to another aspect of the present invention is a first base station that wirelessly communicates with a terminal device using the first wireless communication method. The first base station wirelessly communicates with a terminal device using a second wireless communication method different from the first wireless communication method, and wirelessly communicates with the terminal device using the first wireless communication method. It is an anchor type base station that is provided in a common area together with other first base stations and relays control data between the second base station and the core network.

In the mobility control method according to still another aspect of the present invention, a plurality of first base stations that wirelessly communicate with the terminal device using the first wireless communication system and a second wireless communication system different from the first wireless communication system are used. This is a mobility control method in a mobile communication system in which a second base station that wirelessly communicates with a terminal device is provided in a common area. In the mobility control method, the terminal device connected to a non-anchor type first base station that does not relay control data between the core network and the second base station among the plurality of first base stations is described. It is determined whether or not the terminal device can be connected to the second base station by the second wireless communication method, and the terminal device can be connected to the second base station by the second wireless communication method. When it is determined that the above is the case, control is performed so that the anchor type first base station that relays the control data between the core network and the second base station among the plurality of first base stations is preferentially handed over. Including, and.
In the mobility control method according to still another aspect of the present invention, a plurality of first base stations that wirelessly communicate with the terminal device using the first wireless communication system and a second wireless communication system different from the first wireless communication system are used. This is a mobility control method in a mobile communication system in which a second base station that wirelessly communicates with a terminal device is provided in a common area. The mobility control method is to determine whether or not the terminal device in the unconnected mode is a terminal device that can be connected to the second base station by the second wireless communication method, and the terminal device is the first. 2 Anchor that relays control data between the core network and the second base station among the plurality of first base stations when it is determined that the terminal device can be connected to the second base station by the wireless communication method. It includes controlling so as to preferentially connect to the first base station of the type.

A program according to still another aspect of the present invention uses a plurality of first base stations that wirelessly communicate with a terminal device using the first wireless communication system and a second wireless communication system different from the first wireless communication system. It is a program executed by a computer or a processor provided in a part of the plurality of first base stations in a mobile communication system in which a terminal device and a second base station for wireless communication are provided in a common area. The program includes a program code for functioning as a non-anchor type first base station that does not relay control data between the core network and the second base station, and a terminal device connected to the own station. A program code for determining whether or not the terminal device can be connected to the second base station by the second wireless communication method, and the terminal device can be connected to the second base station by the second wireless communication method. When it is determined that the terminal device is suitable, the anchor type first base station that relays control data between the core network and the second base station among the plurality of first base stations is preferentially handed over. It has a program code for controlling such as.
A program according to still another aspect of the present invention uses a plurality of first base stations that wirelessly communicate with a terminal device using the first wireless communication system and a second wireless communication system different from the first wireless communication system. This is a program executed by a computer or processor provided in a mobile communication system in which a terminal device and a second base station for wireless communication are provided in a common area. The program includes a program code for determining whether or not the terminal device in the unconnected mode is a terminal device that can be connected to the second base station by the second wireless communication method, and the terminal device is the terminal device. When it is determined that the terminal device can be connected to the second base station by the second wireless communication method, the control data is relayed between the core network and the second base station among the plurality of first base stations. It has a program code for controlling so as to preferentially connect to an anchor type first base station.
A program according to still another aspect of the present invention uses a plurality of first base stations that wirelessly communicate with a terminal device using the first wireless communication system and a second wireless communication system different from the first wireless communication system. This is a program executed by a computer or processor provided in a mobile communication system in which a terminal device and a second base station for wireless communication are provided in a common area. In the program, a non-anchor type first base station that does not relay control data between the core network and the second base station among the plurality of first base stations communicates directly between the base stations or the core network and the base. Based on the information acquired by communication with the station and the measurement report received from the terminal device, the program code for detecting the cell of the anchor type first base station and the core of the plurality of first base stations. It has a program code for preferentially connecting to the anchor type first base station that relays control data between the network and the second base station.

According to the present invention, in an NSA mobile communication system in which a first base station of a first wireless communication system and a second base station of a second wireless communication system different from the first wireless communication system coexist in a common area, a non-anchor is used. The first base station of the type automatically detects the first base station of the anchor type in the non-anchor frequency band, and efficiently controls the connection between the terminal device connectable to the second base station and the second base station. It becomes possible.

The explanatory view which shows an example of the schematic structure of the NSA type mobile communication system which concerns on embodiment. The flowchart which shows an example of the automatic setting of an anchor LTE base station and a non-anchor LTE base station. The sequence diagram which shows an example of the connection processing to an anchor LTE base station in an NR correspondence UE. The sequence diagram which shows an example of the handover processing from a non-anchor LTE base station to an anchor LTE base station in an NR-corresponding UE. The explanatory view which shows an example of the mobility operation of the UE (terminal device) in the mobile communication system of FIG. The explanatory view which shows another example of the schematic structure of the NSA type mobile communication system which concerns on embodiment. The explanatory view which shows an example of the mobility operation of the UE (terminal device) in the mobile communication system of FIG. The explanatory view which shows still another example of the schematic structure of the NSA type mobile communication system which concerns on embodiment. The explanatory view which shows an example of the mobility operation of the UE (terminal device) in the mobile communication system of FIG.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is an explanatory diagram showing an example of a schematic configuration of an NSA (Non-Standalone) type mobile communication system 10 according to the present embodiment. The mobile communication system 10 of the present embodiment includes a core network (hereinafter referred to as "EPC" (Evolved Packet Core)) 11 corresponding to the LTE system as the first wireless communication system of the 4th generation LTE, and the LTE system. A plurality of first base stations (hereinafter referred to as "LTE base stations") 31 to 34 that wirelessly communicate with a user device (hereinafter referred to as "UE") 21 and 22 as a terminal device by using the following, which is different from the LTE system. It includes a second base station (hereinafter referred to as “NR base station”) 41 that wirelessly communicates with the UE 21 by using the NR (New Radio) method as the second wireless communication method in the generation (fifth generation) NG.

LTE base stations 31 to 34 and NR base stations 41 are provided in a common area. For example, the LTE base stations 31 to 34 and the NR base station 41 are arranged so that the center position of each cell is the center position of the common area, and at least a part of each cell has a layered cell configuration in which they overlap. ..

The LTE base stations 31 to 34 and the NR base station 41 are each connected to an optical overhang radio unit (RRH) having an antenna and an optical overhang radio device (RRH) via a high-speed transmission cable such as an optical fiber cable. It may be configured by using the controlled / baseband device (BBU: Base Band Unit), and the RRH antenna of each base station may be arranged so as to be at the center position of the common area. Further, the LTE base stations 31 to 34 and the NR base station 41 may be configured as individual devices separated from each other, or at least a part of the LTE base stations 31 to 34 and the NR base station 41 may be integrally configured. You may.

The EPC 11 has nodes and elements such as an MME (Mobile Management Gateway), an S-GW (Serving Gateway), and a P-GW (Packet data gateway Gateway). The MME functions as an access gateway for the control plane (Control-Plane) that handles network control. The S-GW functions as a gateway that handles the user plane (User-plane) of user data. The P-GW functions as a gateway for connecting to an external network.

The EPC 11 is also referred to as an LTE base station (“eNode B” or “eNB”) that constitutes an LTE wireless network E-UTRAN (Evolved Universal Terrestrial Radio Access Network) via a predetermined interface (for example, the S1 interface). It is called.) 31 to 34 are connected.

The EPC 11 can transmit and receive various information / data (for example, UE information, control data, user data, etc.) by communicating with a plurality of LTE base stations 31 to 34 via the predetermined interface.

Further, the plurality of LTE base stations 31 to 34 directly communicate with each other via a predetermined interface (for example, X2 interface) to transmit various information / data (for example, UE information, control data, user data, etc.). You can send and receive.

Further, an NR base station (also referred to as "gNode B" or "gNB") 41 is connected to the EPC 11 via an anchor LTE base station 31 set as a part of a plurality of LTE base stations 31 to 34. ing. The anchor LTE base station 31 and the NR base station 41 are connected via a predetermined interface (for example, an X2 interface). By communicating with the EPC 11 and the NR base station 41 via the anchor LTE base station 31, various information / data (for example, UE information, control data, user data, etc.) can be transmitted / received.

The user data may be directly transmitted and received between the EPC 11 and the NR base station 41 via a predetermined interface (for example, the S1 interface).

The plurality of LTE base stations 31 to 34 and the NR base station 41 may be configured by base stations of the same vendor, or may be configured by base stations of a plurality of vendors. In the example of FIG. 1, LTE base stations 31, 32 and NR base stations 41 are vendor A base stations, and LTE base stations 33 and 34 are vendor B base stations different from vendor A.

Of the plurality of LTE base stations 31 to 34, the LTE base station 31, which is a part of the first base station, is an anchor type LTE base station that relays control data between the EPC 11 and the NR base station 41 (hereinafter, It is called "anchor LTE base station"). The other first base stations, LTE base stations 32 to 34, are non-anchor type LTE base stations (hereinafter, referred to as "non-anchor LTE base stations") that do not relay data between the EPC 11 and the NR base station 41. ). Further, a frequency band used as an anchor when connecting to an NR base station is referred to as an "anchor frequency band", and a frequency band not used as an anchor is referred to as a "non-anchor frequency band". Further, in the following description, when the LTE base station supports both the anchor frequency band and the non-anchor frequency band, the LTE base station when the non-anchor frequency band is used is the "non-anchor LTE base station". It is assumed that the LTE base station when using the anchor frequency band is included in the "anchor LTE base station".

Although FIG. 1 shows a case where there is only one anchor LTE base station 31, a plurality of anchor LTE base stations may be provided in a common area.

The anchor LTE base station 31, the non-anchor LTE base stations 32, 33, 34 and the NR base station 41 use different frequency bands F31, F32, F33, F34 and F41 for wireless communication with the UE, respectively. The frequency bands F31, F32, F33, and F34 used by the anchor LTE base stations 31 and the non-anchor LTE base stations 32, 33, and 34 are, for example, as "E-UTRA operating bands" in the technical specifications of 3GPP: TS 36.101. Of the predetermined bandwidth of the allocated LTE bands (eg, band 1 (B1), band 3 (B3), band 8 (B8), band 28 (B28), band 41 (B41), band 42 (B42)) It can be used by assigning a frequency band. Further, as the frequency band used by the NR base station 41, for example, a frequency band having a predetermined bandwidth in any of 3.7 GHz band, 4.5 GHz band, and 28 GHz band, which is higher than the LTE band, is assigned and used. be able to.

The UE 21 in FIG. 1 is a UE (hereinafter, also referred to as “NR non-compliant UE”) that supports wireless communication by the LTE system but does not support wireless communication by the NR system, and is an anchor LTE base station 31. And wireless communication by the LTE method can be performed between the non-anchor LTE base stations 32 to 34. On the other hand, the UE 22 is an ENDC (Etra NR Dual Connectivity) terminal (hereinafter, also referred to as “NR compatible UE”) that supports both LTE wireless communication and NR wireless communication. The UE 22 can perform wireless communication by the NR method with the NR base station 41 and wireless communication by the LTE method with the anchor LTE base station 31. The UE 22 can also perform LTE wireless communication with the non-anchor LTE base stations 32 to 34.

The UE 21 and UE 22 are provided with control information including communication control parameters as predetermined communication control setting information by a telecommunications carrier that is a provider of mobile communication services, and an SPID (subscriber) that functions as user identification information or terminal identification information. Another identifier) and control information are given. The control information and SPID information are used as a part of the system information (for example, SIB (system information block)) included in the broadcast information at the time of cell selection after the UE is powered on or reset, for example. It is transmitted from stations 31 to 34 and 41 to UEs 21 and 22, and is stored in the internal memory of UEs 21 and 22 or a USIM card as a detachable recording medium mounted on the UE.

The communication control parameters of the control information given to the UE 21 and the UE 22 include "ENDC Capability" as the terminal capability information and "IMMCI (Idle Mode Mobility Control Information)" as the unconnected mode mobility control information. The "ENDC Capacity" is information that can identify whether or not the terminal has a function as an ENDC terminal that supports both LTE wireless communication and NR wireless communication. “IMMCI” is priority information regarding a base station or cell to which UEs 21 and 22 in the unconnected mode (idle mode) are preferentially connected. For example, as the IMMCI for the UE 22 of the ENDC, information for preferentially connecting to the anchor LTE base station 31 is set. On the other hand, as the IMMCI for the UE 21, information for preferentially connecting to a base station designated based on the normal LTE cell priority is set.

The type of UE can be identified by the SPID information held in UEs 21 and 22. For example, according to the SPID information, the UE to which the SPID is assigned is the UE 21 that supports only the wireless communication by the LTE method, or the ENDC that supports both the wireless communication by the LTE method and the wireless communication by the NR method. It is possible to identify whether it is the UE 22 of.

The UE 21 and the UE 22 hold an individual timer T320 preset for each SPID. The timer T320 is a setting that defines the effective time of the communication control parameter of the control information set in the UEs 21 and 22 (for example, the time from when a new value is set in the communication control parameter until the value returns to the initial value). Information.

In the present embodiment, as the value of the timer T320 held in the UE 22 which is an ENDC terminal, for example, a communication control parameter including an IMMCI for preferentially connecting to the anchor LTE base station 31 specially set for the UE 22. However, a value longer than the TA (tracking area) update cycle is set so that it does not return to the initial value.

When a plurality of LTE base stations (eNodeB) serving as anchor LTE base stations 31 and non-anchor LTE base stations 32, 33, and 34 coexist as in the NSA mobile communication system having the above configuration, there are the following problems.
That is, when the terminal device 22 that can be connected to the NR base station 41 is located in the area of the non-anchor LTE base stations 32, 33, 34, the terminal device 22 cannot be connected to the NR base station 41.
An LTE base station operating as a non-anchor LTE base station 32, 33, 34 (including an LTE base station that uses a non-anchor frequency band as a frequency band capable of wireless communication) is an anchor LTE base station 31 (a frequency band capable of wireless communication). It is necessary to detect (including an LTE base station using an anchor frequency band) and connect a terminal device 22 that can be connected to the NR base station 41 to the anchor LTE base station 31.
The non-anchor LTE base stations 32, 33, and 34 need a means to know the anchor LTE base stations 31 mixed in the common area and register their own stations as non-anchor LTE base stations. There is only a method of manual registration in advance by simulation.

Therefore, in the present embodiment, the anchor LTE base station 31 and the non-anchor LTE base stations 32 to 34 are automatically detected and set as shown below.

FIG. 2 is a flowchart showing an example of automatic setting of the anchor LTE base station 31 and the non-anchor LTE base stations 32 to 34.
In FIG. 2, among the plurality of LTE base stations 31 to 34, the LTE base station 31 of the vendor A acquires peripheral cell information from the EPC 11 or the NR base station 41 via the S1 interface or the X2 interface, and a plurality of LTE base stations 31 from the UE 22. Receives the measurement report (MR) of the peripheral cells measured in the frequency band (S101). When the LTE base station 31 detects the cell (NR cell) of the NR base station 41 of the same vendor A as its own station based on the information of the peripheral cell and the measurement report (MR) of the peripheral cell (in S102). YES), set your own station as an anchor LTE base station (S103).

The detection of the cell (NR cell) of the NR base station 41 and the setting as the anchor LTE base station of the own station are based on either the information of the peripheral cell or the measurement report (MR) of the peripheral cell. You may go. Further, the information that the own station is set as the anchor LTE base station may be transmitted from the anchor LTE base station 31 to another base station, or the server provided in the EPC 11 from the anchor LTE base station 31 (for example, each). It may be sent to the base station management server (base station management server) that manages the base station information and registered.

Further, the anchor LTE base station 31 receives and measures for handover with respect to the frequency bands F31 to F34 and F41 including the frequency band F41 used by the cell (NR cell) of the NR base station 41 by the UE 22 connected to its own station. The designation information of the frequency band to be measured may be transmitted to the UE 22 so as to perform the above.

Further, when the UE 22 is located in the central portion other than the end portion in the NR cell, the anchor LTE base station 31 uses the frequency band F31 of its own station and the frequency band F41 of the NR base station 41 at the same time. May be set for data communication by ENDC (Eutra NR Dual Connectivity).

On the other hand, when the UE 22 is located at the end of the NR cell, the radio wave from the NR base station 41 is weak, so that the anchor LTE base station 31 is a non-anchor LTE of the same vendor A as the frequency band F31 used by the own station. The UE 22 may be set to perform data communication by CA (carrier aggregation) by simultaneously using the frequency band F32 used by the base station 32. Here, when there are a plurality of combinations of frequency bands used by anchor LTE base stations and non-anchor LTE base stations of the same vendor that can be used for CA, the UE 22 can obtain the highest throughput from the combinations of the plurality of types. A combination of frequency bands to be used may be selected and determined, and used for data communication by the above CA.

Next, of the plurality of base stations 31 to 34, the remaining other base stations 32 to 34 acquire information on the base stations of the peripheral cells from the EPC 11 or the anchor LTE base station 31 via the S1 interface or the X2 interface, respectively. , Receives measurement reports (MR) of peripheral cells measured in a plurality of frequency bands from UE 22 (S104). When each of the base stations 32 to 34 detects the existence of the anchor LTE base station 31 or its cell based on the information of the peripheral cell and the measurement report (MR) of the peripheral cell (YES in S105), the base station 32 to 34 sets their own station. It is set as a non-anchor LTE base station (S106).

The detection of the existence of the anchor LTE base station 31 or its cell and the setting of the own station as a non-anchor LTE base station are based on either the information of the peripheral cell or the measurement report (MR) of the peripheral cell. You may go there. Further, the information that the own station is set as the non-anchor LTE base station may be transmitted from each of the non-anchor LTE base stations 32 to 34 to another base station, or from each of the non-anchor LTE base stations 32 to 34. It may be transmitted to a server provided in EPC 11 (for example, a base station management server that manages information of each base station) and registered.

Further, each of the base stations 32 to 34 obtains information that the anchor LTE base station 31 is located in the same common area as its own station by accessing a server provided in the EPC 11 (for example, the above-mentioned base station management server). You may.

In addition, the non-anchor LTE base stations 32 to 34 perform reception measurement for handover by the UE 21 connected to the own station for the frequency bands F31 to F34 used other than the cell (NR cell) of the NR base station 41. Regarding the frequency band F41 used in the cell (NR cell) of the NR base station 41, the specified information of the frequency band to be measured may be transmitted to the UE 21 so that the reception measurement for handover is not performed.

Further, when the UE 21 is located in the cell of its own station, the non-anchor LTE base stations 33 and 34 simultaneously use the frequency bands F33 and F34 of the non-anchor LTE base stations 33 and 34 of the same vendor B to be used by the UE 21. Settings may be made for data communication by CA (Carrier Aggregation). Here, when there are a plurality of combinations of frequency bands used by non-anchor LTE base stations of the same vendor that can be used for CA, the non-anchor LTE base station from which the UE 21 can obtain the highest throughput from the plurality of combinations. The combination of frequency bands used in the above may be selected and determined, and may be used for data communication by the above CA.

FIG. 3 is a sequence diagram showing an example of connection processing of the NR-compatible UE 22 to the anchor LTE base station 31 in the present embodiment.
In FIG. 3, when the power of the UE is turned on or reset (S201), the UE 22 measures the received signals from the peripheral cells in the frequency bands F31 to F34 and F41 when the cell in the unconnected state (idle state) is selected. , The measurement report (MR) is transmitted to the anchor LTE base station 31 initially connected to the UE 22 (S202). The anchor LTE base station 31 (or non-anchor LTE base station) to which the UE 22 is initially connected confirms whether or not the UE 22 is an NR-compatible UE (ENDC terminal) based on the SPID or terminal capability information (ENDC Capacity) of the UE 22. Then (S203), it is determined whether or not the UE 22 is in the NR cell based on the measurement report (MR) of the UE 22 (S204).

When the UE 22 is an NR compatible UE (ENDC terminal) (S203) and the UE 22 is in the NR cell (S204), the UE 22 is in the CONNECT state connected to the anchor LTE base station 31 (S205).

Next, when the dual connection control information for additional connection to the NR base station 41 is received from the anchor LTE base station 31 (S206), the UE 22 enters the CONNECT state connected to the NR base station 41 (S207). It becomes a dual connection state connected to the anchor LTE base station 31 and the NR base station 41. As a result, the UE 22 can perform LTE data communication via the anchor LTE base station 31 and NR data communication via the NR base station 41, and the frequency band used by the anchor LTE base station 31 can be used. Data communication by LTE using F31 and the frequency band F41 used by the NR base station 41 at the same time becomes possible.

Next, when the UE 22 moves to the end of the NR cell (S208), the received signal from the NR cell becomes weak, and the UE 22 is in a state where the connection with the NR base station 41 is disconnected (S209). When the dual connection control information for additional connection to the non-anchor LTE base station 32 of the same vendor A is received from the anchor LTE base station 31 (S210), the UE 22 enters the CONNECT state connected to the non-anchor LTE base station 32. (S211), a dual connection state is established in which the anchor LTE base station 31 and the non-anchor LTE base station 32 are connected. As a result, the UE 22 can perform LTE data communication via the anchor LTE base station 31 and the non-anchor LTE base station 32, and the frequency band F31 of the anchor LTE base station 31 and the non-anchor LTE base station 32, Data communication by LTE using F32 at the same time becomes possible.

Next, when the communication with each cell of the LTE base stations 31 and 32 is completed and the Inactivity timer expires, the UE 22 is disconnected from the anchor LTE base station 31 and the non-anchor LTE base station 32, and is in a dual connection state. In the unconnected state (idle state) from (S212). At the timing when the dual connection state or the connected state changes to the unconnected state (idle state), the UE 22 updates the unconnected mode mobility control information (IMMCI) and preferentially connects to the anchor LTE base station 31. Information is set (S213). After this setting, when the UE 22 is in the unconnected state (idle state), the UE 22 is controlled to preferentially connect to the anchor LTE base station 31 based on the unconnected mode mobility control information (IMMCI).

FIG. 4 is a sequence diagram showing an example of handover processing from the non-anchor LTE base station of the NR-compatible UE 22 to the anchor LTE base station in the present embodiment.
In FIG. 4, when the UE 22 is connected to its own station (S301), the non-anchor LTE base station 32 determines whether the UE 22 is an NR-compatible UE (ENDC terminal) based on the SPID of the UE 22 or the ENDC Category of the UE 22. (S302), the measurement report (MR) of the reception signal of the peripheral cell is received from the UE 22 (S303), and based on the measurement report (MR), the UE 22 is located in the anchor base station capable of END C with the NR cell. Judge whether to do (S304)

When the UE 22 is an NR-compatible UE (ENDC terminal) (S302) and the UE 22 is in the NR cell (S304), the non-anchor LTE base station 32 determines the handover to the anchor LTE base station 31 (S304). S305), a handover request is transmitted to the anchor LTE base station 31 via the X2 interface (S306), and a handover instruction is transmitted to the UE 22 (S307). As a result, the UE 22 enters the CONNECT state connected to the anchor LTE base station 31 (S308).

The control and processing (S309 to S316) after the UE 22 is connected to the anchor LTE base station 31 are the same as those of S206 to S213 in FIG. 3, and thus the description thereof will be omitted.

FIG. 5 is an explanatory diagram showing an example of the mobility operation of the UE (terminal device) in the mobile communication system of FIG. FIG. 5 shows the NR cell 41C and the cell of the anchor LTE base station 31 (hereinafter, “anchor LTE cell”) with respect to the common area in the radial direction from the center of the cell of the NR base station 41 (hereinafter, also referred to as “NR cell”) 41C. Also referred to as) 31C and cells of non-anchor LTE base stations 32 to 34 (hereinafter, also referred to as “non-anchor LTE cells”) 32C to 34C are shown. Area 41C'from C1 to C2 in FIG. 5 is an area of an end portion (edge portion) of the NR cell 41C. Further, the right end areas 31C'to 34C'of the anchor LTE cells 31C and the non-anchor LTE cells 32C to 34C in FIG. 5 are areas located outside the service area of the NR cell, respectively.

At least the antennas of the NR base station 41, the anchor LTE base station 31 and the non-anchor LTE base stations 32 to 34 in FIG. 5 are arranged so as to be located at the center C0 of the NR cell 41C. The NR base station 41, the anchor LTE base station 31 and the non-anchor LTE base station 32 are vendor A base stations, and the non-anchor LTE base stations 33 and 34 are vendor B base stations.

As shown in FIG. 2 above, the LTE base station 31 automatically sets its own station as an anchor LTE base station when it detects the cell (NR cell) 41C of the NR base station 41 of the same vendor A as its own station. .. Further, when the other LTE base stations 32 to 34 detect the presence of the anchor LTE base station 31 or its anchor LTE cell 31C in the own cells 32C to 34C, the other LTE base stations 32 to 34 automatically set the own station as a non-anchor LTE base station. ..

In FIG. 5, the NR-compatible UE 22 (1) located in the anchor LTE cell 31C of the vendor A is connected to the anchor LTE base station 31 and the NR base station 41, and is connected to the frequency band F31 of the anchor LTE cell 31C. And data communication by LTE using the frequency band F41 of the NR cell 41C at the same time can be performed.

Further, when the NR-compatible UE 22 (2) is in the non-anchor LTE cell 32C of the vendor A, as shown in FIG. 4 above, the non-anchor LTE base station is the SPID or ENDC of the UE 22 (2). Anchor that determines that the UE 22 (2) is an NR-compatible UE (ENDC terminal) based on the capacity and allows the UE 22 (2) to extend to the NR cell 41C based on the measurement report (MR) received from the UE 22 (2). When it is determined that the base station 31 is in the service area, the handover to the anchor LTE base station 31 is determined, the handover request is transmitted to the anchor LTE base station 31, and the handover instruction is transmitted to the UE 22 (2). As a result, the handover from the non-anchor LTE cell 32C to the anchor LTE cell 31C (HO in the vendor) is performed, and the UE 22 (2) is in the CONNECT state preferentially connected to the anchor LTE base station 31.

When the NR-compatible UE 22 (2) is in the unconnected state (idle state), as shown in FIG. 3 above, the SPID of the UE 22 (2), the terminal capability information (ENDC Capacity), or the unconnected mode mobility control information (IMMCI). ), It is controlled to preferentially connect to the anchor LTE base station 31.

In FIG. 5, the NR-compatible UE 22 (4) located in the portion corresponding to the NR cell end area 41C'of the non-anchor LTE cell 32C is the non-anchor LTE cell 32C, similarly to the UE 22 (2) described above. Handover to the anchor LTE cell 31C (HO in the vendor) is performed, and the CONNECT state is preferentially connected to the anchor LTE base station 31.

In the end area 41C'of the NR cell, the electric field strength of the transmission signal from the NR base station 41 is weak and the throughput may decrease. In order to prevent this decrease in throughput, the NR-compatible UE 22 (3) located in the portion of the anchor LTE cell 31C corresponding to the NR cell end area 41C'is an anchor LTE base station 31 and a non-anchor LTE base station. Data communication by CA (Carrier Aggregation) may be performed by connecting to each of the 32 and using the frequency bands F31 and F32 of the anchor LTE cell 31C and the non-anchor LTE cell 32C at the same time.

Further, the NR non-compliant UE 21 (1) located in the non-anchor LTE cell 33C of the vendor B is connected to each of the non-anchor LTE base stations 33 and 34, and the frequency bands F33 of the non-anchor LTE cells 33C and 34C are connected. Data communication by CA (Carrier Aggregation) in the vendor is performed using F34 at the same time.

Outside the service area of the NR cell 41C in FIG. 5, the NR-compatible UEs 22 (5) and 22 (6) located in the anchor LTE cell 31C'and the non-anchor cell 32C' of the vendor A have their normal LTE cell priorities, respectively. According to this, the mobility operation is executed, and the vendor B is controlled to perform a handover (inter-vendor HO) to the non-anchor LTE cell 33C'for example.

FIG. 6 is an explanatory diagram showing another example of the schematic configuration of the NSA type mobile communication system according to the embodiment. FIG. 7 is an explanatory diagram showing an example of the mobility operation of the UE (terminal device) in the mobile communication system of FIG. The parts common to FIGS. 1 to 5 in FIGS. 6 and 7 will not be described.

In the examples of FIGS. 6 and 7, the non-anchor LTE base station 35 of the vendor B is arranged in place of the non-anchor LTE base station 32 of the vendor A in FIGS. 1 to 5, and the non-anchor LTE base station 35 of the vendor B is arranged in the LTE cells 33C to 35C of the vendor B. This is an example of preferentially executing CA (Carrier Aggregation).

When the LTE base station 35 detects the presence of the anchor LTE base station 31 or its anchor LTE cell 31C in its own cell 35C, the LTE base station 35 automatically sets its own station as a non-anchor LTE base station.

In FIG. 7, when the NR-compatible UE 22 (2) is in the non-anchor LTE cell 35C of the vendor B, as shown in FIG. 4 above, the non-anchor LTE base station 35 is the UE 22 (2). The UE 22 (2) is determined to be an NR compatible UE (ENDC terminal) based on the SPID or the ENDC Capacity, and the UE 22 (2) is the NR cell 41C based on the measurement report (MR) received from the UE 22 (2). When it is determined that the user is in the anchor base station 31 capable of ENDC, a handover request to the anchor LTE base station 31 is determined, a handover request is transmitted to the anchor LTE base station 31, and a handover instruction is given to the UE 22 (2). Send. As a result, the handover from the non-anchor LTE cell 35C to the anchor LTE cell 31C (inter-vendor HO) is performed, and the UE 22 (2) is in the CONNECT state preferentially connected to the anchor LTE base station 31.

When the NR-compatible UE 22 (2) is in the unconnected state (idle state), as shown in FIG. 3 above, the SPID of the UE 22 (2), the terminal capability information (ENDC Capacity), or the unconnected mode mobility control information (IMMCI). ), It is controlled to preferentially connect to the anchor LTE base station 31.

Further, the NR non-compliant UE 21 (1) located in the non-anchor LTE cell 35C of the vendor B is connected to each of the non-anchor LTE base stations 33, 34, 35, and the non-anchor LTE cells 33C, 34C, 35C. Data communication by CA (Carrier Aggregation) using the frequency bands F33, F34, and F35 at the same time is performed.

In FIG. 7, in the end area 41C'of the NR cell, the electric field strength of the transmission signal from the NR base station 41 is weak and the throughput may decrease. In order to prevent this decrease in throughput, the NR-compatible UE 22 (3) located in the portion corresponding to the NR cell end area 41C'of the anchor LTE cell 31C of the vendor A is transferred from the anchor LTE cell 31C to the non-anchor LTE. Handover to cell 35C (inter-vendor HO) is performed.

Further, in order to prevent a decrease in throughput in the end area 41C'of the NR cell, the NR-compatible UE 22 (which is located in the portion corresponding to the NR cell end area 41C' of the non-anchor LTE cell 35C of the vendor B ( 4) is connected to each of the non-anchor LTE base stations 33, 34, 35 of the vendor B, and uses the frequency bands F33, F34, F35 of the non-anchor LTE cells 33C, 34C, 35C at the same time to carry out CA (carrier aggregation) in the vendor. ) For data communication.

Outside the service area of the NR cell 41C in FIG. 7, the NR-compatible UEs 22 (5) and 22 (6) located in the anchor LTE cell 31C'of the vendor A and the non-anchor cell 35C' of the vendor B are the normal LTE, respectively. The mobility operation is executed according to the cell priority, and is controlled to, for example, perform a handover (inter-vendor HO) to the non-anchor LTE cell 33C'of the vendor B. Further, the NR-compatible UE 22 (7) and the non-NR-compatible UE 21 (2) located in the non-anchor LTE cell 33C'of the vendor B are connected to the non-anchor LTE base stations 33 and 34 of the vendor B, respectively, and are non-anchor. Data communication by CA (Carrier Aggregation) in Vendor B is performed by using the frequency bands F33 and F34 of LTE cells 33C and 34C at the same time.

FIG. 8 is an explanatory diagram showing another example of the schematic configuration of the NSA type mobile communication system according to the embodiment. FIG. 9 is an explanatory diagram showing an example of the mobility operation of the UE (terminal device) in the mobile communication system of FIG. The parts common to FIGS. 1 to 7 in FIGS. 8 and 9 will not be described.

In FIGS. 8 and 9, the NR base station 42, the anchor LTE base station 36, and the non-anchor LTE base station 35 are the vendor B base stations, and the non-anchor LTE base stations 37 and 38 are the vendor A base stations. is there.

As shown in FIG. 2 above, the LTE base station 36 automatically sets its own station as an anchor LTE base station when it detects the cell (NR cell) 42C of the NR base station 42 of the same vendor B as its own station. .. Further, when the other LTE base stations 35, 37, 38 detect the presence of the anchor LTE base station 36 or its anchor LTE cell 36C in the own cells 35C, 37C, 38C, respectively, the other LTE base stations make their own stations non-anchor LTE base stations. Automatically set as.

In FIG. 9, the NR-compatible UE 22 (1) located in the anchor LTE cell 36C of the vendor B is connected to the anchor LTE base station 36 and the NR base station 42, and is connected to the frequency band F36 of the anchor LTE cell 36C. And CA (Carrier Aggregation) data communication using the frequency band F42 of the NR cell 42C at the same time can be performed.

Further, when the NR-compatible UE 22 (2) is in the non-anchor LTE cell 37C of the vendor A, as shown in FIG. 4 above, the UE 22 (2) is NR based on the SPID of the UE 22 (2). When it is determined that the UE (ENDC terminal) is compatible, the vendor B determines the handover to the anchor LTE base station 36, transmits the handover request to the anchor LTE base station 36, and transmits the handover instruction to the UE 22 (2). .. As a result, a handover (inter-vendor HO) is performed from the non-anchor LTE cell 37C of the vendor A to the anchor LTE cell 36C of the vendor B, and the UE 22 (2) is preferentially connected to the anchor LTE base station 36 in the CONNECT state. become.

When the NR-compatible UE 22 (2) is in the unconnected state (idle state), as shown in FIG. 3 above, the SPID of the UE 22 (2), the terminal capability information (ENDC Capacity), or the unconnected mode mobility control information (IMMCI). ), It is controlled to preferentially connect to the anchor LTE base station 36.

In FIG. 9, the NR-compatible UE 22 (3) located in the portion corresponding to the NR cell end area 42C'of the non-anchor LTE cell 37C of the vendor A is the vendor A, similarly to the UE 22 (2) described above. Handover (inter-vendor HO) from the non-anchor LTE cell 37C of the above to the anchor LTE cell 36C of the vendor B is performed, and the CONNECT state is preferentially connected to the anchor LTE base station 36.

In the end area 42C'of the NR cell, the electric field strength of the transmission signal from the NR base station 42 is weak and the throughput may decrease. In order to prevent this decrease in throughput, the NR-compatible UE 22 (4) located in the portion corresponding to the NR cell end area 42C'of the anchor LTE cell 37C is the non-anchor LTE base station 37, 38 of the vendor A. It is connected to each and performs data communication by CA (Carrier Aggregation) using the frequency bands F37 and F38 of the non-anchor LTE cells 37C and 38C at the same time.

Similarly, the NR non-compliant UE 21 (1) located in the non-anchor LTE cell 37C of the vendor A is connected to each of the non-anchor LTE base stations 37 and 38 of the vendor A, and the non-anchor LTE cells 37C and 38C are connected. Data communication by CA (Carrier Aggregation) using the frequency bands F37 and F38 at the same time is performed.

Outside the service area of the NR cell 42C in FIG. 9, the NR-compatible UEs 22 (5) and 22 (6) located in the anchor LTE cell 36C'and the non-anchor cell 35C' of the vendor B have normal LTE cell priorities, respectively. According to this, the mobility operation is executed, and is controlled to perform a handover (inter-vendor HO) to the non-anchor LTE cell 37C'of the vendor A, for example. Further, the NR-compatible UE 22 (7) and the non-NR-compatible UE 21 (2) located in the non-anchor LTE cell 37C'of the vendor A are connected to the non-anchor LTE base stations 37 and 38 of the vendor A, respectively, and are non-anchor. Data communication by CA (Carrier Aggregation) in Vendor A is performed by using the frequency bands F33 and F34 of LTE cells 37C and 38C at the same time.

As described above, according to the present embodiment, the LTE base station (first base station) of the LTE system (first wireless communication system) and the NR base station (second base station) 41 of the NR system (second wireless communication system), In the NSA mobile communication system in which 42 and 42 coexist in a common area, the anchor type LTE base stations 31 and 36 automatically detect the NR cells 41C and 42C overlapping the own station's cell and set the own station as the anchor type LTE. However, the non-anchor type LTE base station automatically detects the cells of the anchor type LTE base stations (including the anchor LTE base stations using the non-anchor frequency band) 32 to 38 that overlap with the cells of the own station, and the own station. Can be set as a non-anchor type LTE base station, so that manual registration of the anchor type LTE base station and the non-anchor type LTE base station becomes unnecessary, and the terminal device 22, which can be connected to the NR base stations 41 and 42, 22 (1) to 22 (7) can be efficiently connected to the NR base stations 41 and 42 via the anchor type LTE base station.

The processing process described in the present specification and components such as a mobile communication system, a terminal device, and a terminal device (UE) can be implemented by various means. For example, these steps and components may be implemented in hardware, firmware, software, or a combination thereof.

Regarding hardware implementation, means such as a processing unit used to realize the above steps and components in an entity (for example, various wireless communication devices, eNodeB, gNodeB, terminal, hard disk drive device, or optical disk drive device). Is one or more application-specific ICs (ASICs), digital signal processors (DSPs), digital signal processing devices (DSPDs), programmable logic devices (PLDs), field programmable gate arrays (FPGAs). , Processors, controllers, microcontrollers, microprocessors, electronic devices, other electronic units designed to perform the functions described herein, computers, or combinations thereof. ..

For firmware and / or software implementation, means such as processing units used to implement the above components are programs (eg, procedures, functions, modules, instructions) that perform the functions described herein. , Etc.) may be implemented. Generally, any computer / processor readable medium that clearly embodies the firmware and / or software code is a means such as a processing unit used to implement the steps and components described herein. May be used to implement. For example, the firmware and / or software code may be stored in memory and executed by a computer or processor, for example, in a control device. The memory may be implemented inside the computer or processor, or may be implemented outside the processor. Further, the firmware and / or software code may be, for example, a random access memory (RAM), a read-only memory (ROM), a non-volatile random access memory (NVRAM), a programmable read-only memory (PROM), or an electrically erasable PROM (EEPROM). ), FLASH memory, floppy (registered trademark) discs, compact discs (CDs), digital versatile discs (DVDs), magnetic or optical data storage devices, etc. Good. The code may be executed by one or more computers or processors, or the computers or processors may be made to perform functional embodiments described herein.

Further, the medium may be a non-temporary recording medium. Further, the code of the program may be read and executed by a computer, a processor, or another device or device machine, and the format thereof is not limited to a specific format. For example, the code of the program may be any of source code, object code, and binary code, or may be a mixture of two or more of these codes.

Also, the description of the embodiments disclosed herein is provided to allow one of ordinary skill in the art to manufacture or use the disclosure. Various amendments to this disclosure will be readily apparent to those of skill in the art and the general principles defined herein are applicable to other variations without departing from the spirit or scope of this disclosure. Therefore, this disclosure is not limited to the examples and designs described herein, but should be accepted in the broadest range consistent with the principles and novel features disclosed herein.

10: Mobile communication system 11: Core network (EPC)
21,21 (1), 21 (2): UE (terminal device) that does not support NR
22, 22 (1) to 22 (7): NR compatible UE (terminal device)
31: Vendor A anchor LTE base station (first base station)
32, 37, 38: Vendor A non-anchor LTE base station (first base station)
33, 34, 35: Vendor B non-anchor LTE base station (first base station)
36: Vendor B anchor LTE base station (first base station)
31C to 38C: LTE cell 31C'to 38C': Part located outside the NR cell range of the LTE cell 41: Vendor A's NR base station (second base station)
41C: NR cell 41C': End of NR cell 42: Vendor B NR base station (second base station)
42C: NR base station cell 43C': NR base station cell end

Claims (13)

A first base station that wirelessly communicates with a terminal device using the first wireless communication method and a second base station that wirelessly communicates with the terminal device using a second wireless communication method different from the first wireless communication method. A mobile communication system installed in a common area
A plurality of the first base stations are provided in the common area.
Of the plurality of first base stations, some first base stations are anchor-type first base stations that relay control data between the core network and the second base station, and the other first base station. The base station is a non-anchor type first base station that does not relay control data between the core network and the second base station.
The other first base station is characterized in that when it detects a cell of the anchor type first base station that overlaps with the cell of its own station, it sets its own station as the non-anchor type first base station. Mobile communication system. In the mobile communication system of claim 1,
The cell of the anchor type first base station is detected based on the information acquired by the direct communication between the base stations or the communication between the core network and the base station and the measurement report (MR) received from the terminal device. A mobile communication system characterized by this. In the mobile communication system according to claim 1 or 2.
The non-anchor type first base station refers to the non-anchor type first base station when the terminal device connected to the own station is a terminal device that can be connected to the second base station by the second wireless communication method. A mobile communication system characterized in that control is performed so that an anchor-type first base station is preferentially handed over to the anchor-type first base station. In the mobile communication system according to any one of claims 1 to 3.
When the terminal device that can be connected to the second base station by the second wireless communication method is located in the overlapping area of the cell of the second base station and the cell of the anchor type first base station in the unconnected mode, the said An anchor type first base station is a mobile communication system characterized in that it is preferentially connected by the terminal device. In the mobile communication system according to any one of claims 1 to 4.
When the terminal device connected to the own station is located at the end of the cell of the second base station, the anchor type first base station causes the terminal device to be removed from the anchor type first base station. A mobile communication system characterized in that it is controlled so that an anchor type first base station is preferentially handed over. In the mobile communication system according to any one of claims 1 to 5.
The anchor type first base station and the non-anchor type first base station are of the first base station when the terminal device connected to the own station is located outside the cell of the second base station. A mobile communication system characterized in that mobility is controlled according to a priority set for a cell. In the mobile communication system according to any one of claims 1 to 6.
The anchor type first base station and the non-anchor type first base station are preferentially connected to the anchor type first base station when the terminal device connected to the own station is in the unconnected mode. A mobile communication system comprising transmitting unconnected mode mobility control information (IMMCI) to the terminal device. In the mobile communication system of claim 7,
A mobile communication system characterized in that the valid time of the unconnected mode mobility control information (IMMCI) is longer than the update cycle of the tracking area by the terminal device. In the mobile communication system according to any one of claims 1 to 8.
It is characterized in that it is determined whether or not the terminal device is a terminal device that can be connected to the second base station based on at least one of the terminal identification information and the terminal capability information stored in the terminal device. Mobile communication system. In the mobile communication system according to any one of claims 1 to 9.
The measurement of the received signal for the cell of the second base station by the terminal device is performed when it is connected to the anchor type first base station, and when it is not connected to the anchor type first base station. A mobile communication system characterized in that it is not performed. A plurality of first base stations that wirelessly communicate with the terminal device using the first wireless communication method and a second base station that wirelessly communicates with the terminal device using a second wireless communication method different from the first wireless communication method. It is a mobility control method in a mobile communication system provided in a common area.
Of the plurality of first base stations, a terminal device connected to a non-anchor type first base station that does not relay control data between the core network and the second base station is subjected to the second wireless communication method. Determining whether or not the terminal device can be connected to the second base station
When it is determined that the terminal device is a terminal device that can be connected to the second base station by the second wireless communication method, between the core network and the second base station among the plurality of first base stations. A mobility control method comprising: controlling so as to preferentially hand over to an anchor-type first base station that relays control data in the above. A plurality of first base stations that wirelessly communicate with the terminal device using the first wireless communication method and a second base station that wirelessly communicates with the terminal device using a second wireless communication method different from the first wireless communication method. It is a mobility control method in a mobile communication system provided in a common area.
Determining whether or not the terminal device in the unconnected mode is a terminal device that can be connected to the second base station by the second wireless communication method.
When it is determined that the terminal device is a terminal device that can be connected to the second base station by the second wireless communication method, between the core network and the second base station among the plurality of first base stations. A mobility control method comprising: controlling so as to preferentially connect to an anchor type first base station that relays control data. A plurality of first base stations that wirelessly communicate with the terminal device using the first wireless communication method and a second base station that wirelessly communicates with the terminal device using a second wireless communication method different from the first wireless communication method. A program executed by a computer or processor provided in a part of the plurality of first base stations in a mobile communication system provided in a common area.
A program code for functioning as a non-anchor type first base station that does not relay control data between the core network and the second base station, and
A program code for determining whether or not the terminal device connected to the own station is a terminal device that can be connected to the second base station by the second wireless communication method.
When it is determined that the terminal device is a terminal device that can be connected to the second base station by the second wireless communication method, between the core network and the second base station among the plurality of first base stations. A program characterized by having a program code for controlling so as to preferentially hand over to an anchor type first base station that relays control data in the above.

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