JP2014064202A - Exchange, exchange control program, exchange control method, radio control device, and mobile communication system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an exchange, exchange control program, and exchange control method that are suitable for providing a mobile terminal with frequency information on a femtocell for by use of a standard field of a standard signal.SOLUTION: An exchange MME and an SGSN obtain in-zone policy information which is information to set whether a mobile terminal UE is preferentially situated in an LTE femtocell or not, terminal specification information on the mobile terminal UE, and position registration area information on a macrocell covering a femtocell situated in the past from a subscriber information server HSS, derive an SPID on the basis of the terminal specification information, convert the derived SPID into a value by which the LTE femtocell is preferentially searched for on the basis of the in-zone policy information and the position registration area information if the in-zone policy information is B mode, and convert the derived SPID into a value by which the LTE femtocell is preferentially searched for if the in-zone policy information is C mode and if the position registration area where the mobile terminal UE is currently situated and the obtained position registration area accord with each other.

Description

  The present invention relates to a technique for preferentially placing a mobile terminal in a small cell in a mobile communication system in which communication networks of a plurality of types of communication systems coexist.

Conventionally, for example, in a mobile communication system configured to include a 3G communication network, for a macro cell that provides a communication service in a relatively large cell (hereinafter referred to as “macro cell”) having a radius of several hundred m to several tens of km. In addition to the radio base stations, femto cell radio base stations that provide communication services in extremely small cells (hereinafter referred to as “femto cells”) having a radius of several m to several tens m are installed.
Such a femtocell radio base station is not installed by a telecommunications carrier, but by a telecommunications carrier subscriber (see Non-Patent Document 1).
For this reason, the frequency band of the macro cell is usually shared by a large number of mobile terminals under the macro cell, whereas the subscriber who installed the radio base station for the femto cell may occupy the frequency band of the femto cell. it can.

  In addition, the femtocell radio base station is connected to the core network of the communication carrier using the subscriber's user line instead of the dedicated line. Therefore, it is possible to reduce the equipment burden on the telecommunications carrier and to reduce the communication fee of the subscriber. In addition, the effect of traffic offload by using the femtocell can be expected.

  In addition, when a subscriber (a registered user of a femtocell) who installed a radio base station for femtocells uses the femtocell for the first time, the macrocell (hereinafter referred to as a cover cell) that usually includes the area of the femtocell. In this area, a procedure for inputting a specific femto cell number to the mobile terminal and making a call is performed. Alternatively, a procedure of transmitting USSD (Unstructured Supplementary Service Data) including a specific number by a menu operation using a mobile terminal is taken (see Patent Document 1). Hereinafter, these procedures are referred to as special number transmission.

  Specifically, as shown in FIG. 14, when a special number is transmitted from a mobile terminal located in a cover cell to an MSC (Mobile Switching Center), an existing connection release process is executed. Then, a control signal including information (such as a femtocell location flag) for transmitting the mobile terminal to the femtocell is sequentially transmitted from the MSC to the IPRNC (Internet Protocol Radio Network Controller) and further from the IPRNC to the mobile terminal. The Thereby, the mobile terminal searches for the corresponding femtocell based on the information included in the control signal. When the mobile terminal finds the corresponding femto cell by the cell search, as shown in FIG. 15, the mobile terminal disconnects from the currently existing cover cell and moves to the corresponding femto cell.

Hereinafter, based on FIG. 16, a specific operation sequence when the special number transmission by the menu operation is performed will be described.
As shown in FIG. 16, by sending a special number by the user's menu operation, first, a USSD including a specific number (for example, * 137 #) is transmitted from the mobile terminal to the MSC on the “Register” signal (S3000). ). Here, transmission and reception of signals between the mobile terminal and the MSC are basically performed via a Macro BTS (Base Transmission Station) and an IPRNC which are base stations corresponding to the macro cell.

  When the MSC receives the “Register” signal, a new USSD code (specific number) is recognized (S3002). When the new USSD code is recognized, an existing connection release process is executed among the MSC, IPRNC, and mobile terminal. First, the MSC stores the frequency search activation in the memory, and then stores the search frequency (initially f = 0) (S3004). Here, when there is storage data of the frequency of the femtocell corresponding to the location registration area (LA (Location Area)) of the corresponding macro cell in the frequency storage processing of system guidance (described later), f = storage frequency is set. Next, a “Release Complete” signal is transmitted from the MSC to the mobile terminal to notify that the connection has been successfully released (S3006). Next, a disconnection signal (“Iu Connection Release” signal) including the frequency information of the femtocell (CSG (Closed Subscriber Group) Carrier Number = f)) is transmitted from the MSC to the IPRNC (S3008). This control signal is a signal of the RANAP (Radio Access Network Application Part) protocol, and the frequency information of the femtocell is, for example, in a unique data field of the communication carrier provided for the “Iu Connection Release” signal. Is set. On the other hand, the IPRNC that has received the “Iu Connection Release” signal transmits an RRC (Radio Resource Control) connection disconnection (release) signal (“RRC Connection Release” signal) including frequency information of the femtocell to the mobile terminal (S3010). ). Thereby, when the RRC connection is released, the mobile terminal performs a cell search using the frequency of the femto cell. Then, when the mobile terminal finds the corresponding femto cell by the cell search, it disconnects from the currently existing macro cell and moves to the corresponding femto cell.

  Thereafter, CS (Circuit Switched) single attach or CS single location registration occurs, and a “Location Updating Request” signal is transmitted from the mobile terminal to the MSC (S3012). Thereby, in MSC and SGSN, the frequency memory | storage process at the time of femto BTS service area is performed (S3014). Specifically, the LAC (Location Area Code) of the macro cell covering the femto cell where the mobile terminal is located and the frequency of the femto cell are stored in the subscriber profile. The LAC of the macro cell at this time is referred to as HomeLAC. Thereafter, existing location registration processing is performed.

Next, a conventional operation sequence for voluntarily guiding a mobile terminal to a femtocell that has been in the area once will be described with reference to FIG.
First, at power-on or location update, the mobile terminal transmits an “Attach Request” signal or a “RAU (Routing Area Update) Request” signal to an SGSN (Serving GPRS Support Node) (S3100). Next, an “Initial UE Message” signal including an LAI (Location Area Identifier) is transmitted from the IPRNC to the SGSN (S3102). Here, the LAI includes a PLMN (Public Land Mobile Network) id and the LAC of the macro cell where the mobile terminal is located. Thereafter, existing location registration processing is performed. First, an “Attach Accept” signal or an “RAU Accept” signal is transmitted from the corresponding SGSN (hereinafter referred to as SGSN # 1) to the mobile terminal (S3102). Next, the “Attach Complete” signal or the “RAU Complete” signal is transmitted from the mobile terminal that has received this signal to the SGSN (S3104). Next, a “GMM information (General Packet Radio Service Mobility Management information)” signal is transmitted from the SGSN that has received this signal to the IPRNC (S3106). Thereafter, the SGSN compares the LAC received by the “Initial UE Message” signal with the HomeLAC of the subscriber profile, and determines whether or not they match (S3108). When it is determined that they match, the SGSN transmits an “Iu Release Command” signal including the femto cell ID (Femto ID) and frequency information (CSG Carrier Number) to the IPRNC (S3110). On the other hand, if it is determined that they do not match, the SGSN transmits a normal “Iu Release Command” signal to the IPRNC (S3112). Thereafter, the IPRNC that has received this signal transmits an “RRC Connection Release” signal including frequency information of the femtocell to the mobile terminal. The mobile terminal that has received this signal performs a cell search using the frequency information of the femto cell and finds the corresponding femto cell, and moves from the currently existing macro cell to the corresponding femto cell.

  On the other hand, a mobile communication system including an LTE (Long Term Evolution) communication network in addition to a 3G communication network belongs to the CSG in the standard specification established by the 3GPP (3rd Generation Partnership Project) standard. There are specifications for a hybrid femtocell that is open to non-users. In particular, in “LTE Release 9,” it is possible to notify whether a hybrid femtocell belongs to a CSG by using a 1-bit flag together with a CSG identifier (ID). That is, when it is determined by the flag that it belongs to the CSG, the communication service is provided only to registered users as in the case of the 3G-type femtocell. On the other hand, when it is determined that the flag does not belong to the CSG, the communication service is also provided to a user who does not belong to the CSG (see Non-Patent Document 2).

  In particular, the femtocell, which is generally released, is installed not only in the registered user's house but also in a shaded area that cannot be covered by a macro cell by a communication carrier. Therefore, it is assumed that more base stations are installed than 3G-type femtocell base stations. Therefore, it can be expected that the effect of traffic offload becomes more remarkable by preferentially guiding the mobile terminal to the LTE femtocell. Moreover, since the number of mobile terminals that can be located in the femtocell is limited, it is possible to increase the data communication capacity per mobile terminal. Therefore, by staying in the femtocell, it is possible to receive a communication service with higher quality than the macrocell.

WO2009 / 148167

NTT DOCOMO Technical Journal Vol.17 No.4 (pp19-25) NTT DOCOMO Technical Journal Vol.18 No.1 (pp48-55)

However, in the above prior art, in order to provide the femto cell frequency information to the mobile terminal, a field uniquely set by the communication carrier for the standard signal is used instead of the standard field of the signal used as a standard. I used it.
In addition, in the above conventional technology, even during packet communication, the process of spontaneously moving to a femtocell that has been in the past is performed, so packet communication is possible regardless of the user's intention. There was a problem of forcibly disconnecting.

  The present invention has been made to solve the above-described problems, and is an exchange, an exchange control program, and an exchange control method suitable for providing femtocell frequency information to a mobile terminal using a standard field of a standard signal. An object of the present invention is to provide a mobile communication system.

[Form 1]
In order to solve the above-described problem, the exchange according to the first aspect of the present invention is configured to include a plurality of mobile communication networks respectively corresponding to a plurality of types of mobile communication schemes, and has a communication area with a mobile terminal. In a mobile communication system configured to include a large cell that is a relatively large cell and a small cell in which the size of the communicable area is smaller than the large cell, the large cell is An exchange having a radio control device for controlling radio communication with the mobile terminal via the small cell and radio communication with the mobile terminal via the small cell,
Location policy information, which is information for setting whether to preferentially reside in the small cell of the mobile terminal set in advance, is acquired from a subscriber information holding device provided in the mobile communication system. Area policy information acquisition unit,
Priority frequency discrimination information that is information for discriminating a frequency band of a cell corresponding to a communication method that the mobile terminal should prevail in, and the location policy information acquired by the location policy information acquisition unit, A discrimination information setting unit for setting priority frequency discrimination information including discrimination information capable of discriminating a frequency band of a cell to be preferentially located based on
A priority frequency discrimination signal transmission unit that transmits a priority frequency discrimination signal, which is a control signal including the priority frequency discrimination information set by the discrimination information setting unit, to the radio network controller.

  With such a configuration, the in-zone policy information acquisition unit can acquire in-zone policy information that is information for setting whether or not the mobile terminal is in a small cell from the subscriber information holding device. It is. Further, the discrimination information setting unit may set priority frequency discrimination information including discrimination information that can discriminate the frequency band of a cell that should prevail based on the priority frequency discrimination information and the location policy information. Is possible. Furthermore, the priority frequency discrimination signal transmission unit can transmit a priority frequency discrimination signal including the priority frequency discrimination information set by the discrimination information setting unit to the radio control apparatus.

  Here, for example, in a 3G communication network, there is a RANAP protocol that is a standard protocol for exchanging control information between a UTRAN (UMTS Terrestrial Radio Access Network) and a core network. The RANAP protocol is used, for example, between a radio network controller (RNC) and an exchange (SGSN) in a W-CDMA communication network. In an LTE communication network, S1-AP (S1 Application Protocol) is a standard protocol for an application layer between a base station (eNodeB) having a function of a radio network controller and an exchange (Mobility Management Entity). is there. In these protocols, SPID (Subscriber Profile ID for Radio Frequency Priority) that can be set in a standard field provided in advance in the control signal is defined as priority frequency discrimination information.

With the above configuration, for example, in a mobile communication system configured to include a 3G communication network and an LTE communication network, a frequency band that should be preferentially located based on SPID and location policy information It is possible to set priority frequency discrimination information including discrimination information corresponding to. As a result, the discriminating information that can discriminate whether or not the small cell is preferentially located by using the standard field of the standard signal without setting the carrier's own field for the standard signal. Including priority frequency discrimination information can be set. And it becomes possible to transmit the control signal containing this priority frequency discrimination | determination information to a radio | wireless control apparatus. Thereby, the effect that the mobile communication system with comparatively high versatility can be constructed is obtained.
Here, the small cell corresponds to, for example, a micro cell, a pico cell, or a femto cell.

  Further, the location policy information includes, for example, (1) the mobile terminal is not preferentially located in the small cell, (2) the mobile terminal is preferentially located for all the small cells, (3) This is information for setting that the mobile terminal is preferentially located in a specific small cell. That is, the discrimination information setting unit sets the priority frequency discrimination information so that the mobile terminal is not preferentially searched for the small cell if the location policy information is (1). Further, the discrimination information setting unit sets the priority frequency discrimination information so as to preferentially search all the small cells in the case of the in-zone policy information of (2). Further, the discrimination information setting unit sets the priority frequency discrimination information so as to preferentially search for a specific small cell if it is the in-zone policy information of (3) above.

[Form 2]
Further, in the exchange of aspect 2, in the configuration of aspect 1, the area policy information includes small cell priority area policy information for preferentially locating the mobile terminal to all the small cells. And
If the determination information setting unit determines that the area policy information is the small cell priority area policy information, it determines that the frequency band of the cell to be preferentially located is the frequency band of the small cell. It is characterized in that priority frequency discrimination information including possible discrimination information is set.

With such a configuration, the discrimination information setting unit can set priority frequency discrimination information including discrimination information that can discriminate the frequency band of a small cell as a frequency band to be preferentially searched.
As a result, it is possible to preferentially place the mobile terminal in the small cell without any manual operation by the user such as special number transmission in any macro cell. Therefore, it is possible to provide a relatively high quality communication service to the user's mobile terminal and to improve the effect of traffic offload.

[Form 3]
Further, in the exchange of mode 3, in the configuration of mode 1 or 2, the location policy information gives priority to the mobile terminal from the specific large cell to the small cell existing in the large cell. Contains specific small cell priority location policy information to be
Based on a control signal related to location registration that occurs in response to the mobile terminal being in the small cell, the identification information of the large cell including the area of the small cell in which the mobile terminal is located A first large cell identification information registration unit for registering certain first large cell identification information in the subscriber information holding device;
A first large cell identification information acquisition unit for acquiring the first large cell identification information from the subscriber information holding device;
A control signal receiving unit that receives a control signal including second large cell identification information that is identification information of the large cell in which the mobile terminal is located from the radio control device;
The discrimination information setting unit determines the content of the location policy information in response to receiving the control signal by the control signal reception unit, and the location policy information is the specific small cell priority location policy information. If it is determined that there is, the first large cell identification information acquired by the first large cell identification information acquisition unit is compared with the second large cell identification information included in the control signal received by the control signal reception unit. If it is determined that the first large cell identification information and the second large cell identification information match, it is possible to determine that the frequency band of the cell to be preferentially located is the frequency band of the small cell When the priority frequency discrimination information including information is set and it is determined that the first large cell identification information and the second large cell identification information do not match, the frequency band of the cell to be preferentially located is the movement Based on device specifications It is characterized by setting the priority frequency discrimination information including a discernable determination information that it is a frequency band of a preset communication method.

  With such a configuration, in the first large cell identification information registration unit, the mobile terminal subscribes to the first large cell identification information of the large cell that includes the small cell when the mobile terminal is located in the small cell. Can be registered in the person information holding device. Further, the first large cell identification information acquisition unit can acquire the first large cell identification information from the subscriber information holding device. Furthermore, the second large cell identification information acquisition unit can acquire the second large cell identification information of the large cell where the mobile terminal is located from the radio control apparatus. Then, the discrimination information setting unit compares the first large cell identification information and the second large cell identification information in response to receiving the control signal by the control signal receiving unit, and determines that the two match, It is possible to set priority frequency discrimination information including discrimination information capable of discriminating a frequency band in which a cell is preferentially searched. On the other hand, if the discrimination information setting unit determines that the two do not match, the discrimination information setting unit may set priority frequency discrimination information including discrimination information that can discriminate a frequency band of a communication scheme set in advance based on the specifications of the mobile terminal. Is possible.

  Thereby, when the mobile terminal is located in a macro cell including a small cell that has been in the past, the mobile terminal can be preferentially located in the small cell. Therefore, since the small cell can be searched only when it has been in a specific large cell including a small cell that has been in the past in the past, In addition to the effect, it is possible to save power consumption.

[Form 4]
Furthermore, in the switching device according to mode 4, in the configuration according to any one of modes 1 to 3, the determination information setting unit is configured such that the frequency band of the cell to be preferentially located is the frequency band of the small cell. When setting the priority frequency discrimination information including discrimination information capable of discriminating that, the frequency that should be located in the next highest priority is the frequency band of the small cell corresponding to a preset communication method as the highest priority The band is a frequency band of a communication system cell set in advance based on the specifications of the mobile terminal, and the frequency band to be preferentially located after the frequency band is set to be a frequency band of another communication system cell. The priority frequency discriminating information including discriminating information capable of discriminating a plurality of frequency bands to which priorities are assigned is set.
With such a configuration, when a small cell is not found by a cell search in the mobile terminal, the mobile terminal can be smoothly switched to a large cell in a preset communication method, a large cell in another communication method, or the like. It is possible to move to the area.

[Form 5]
Further, in the exchange of the form 5, in contrast to the configuration of any one of the forms 1 to 4, the plurality of types of communication methods include a 3G (3rd Generation) method,
The priority frequency discrimination information is an SPID (Radio Access Network Application Part) protocol control signal, which is a communication protocol used in communication between the exchange and the radio network controller, in a 3G communication network. Subscriber Profile ID for Radio Frequency Priority).

  With such a configuration, the SPID included in the control signal of the RANAP protocol can be used as the priority frequency discrimination information in the 3G communication network. As a result, the priority frequency including the discrimination information that can discriminate whether or not the small cell is preferentially located using the standard field without setting the carrier's own field for the standard signal. The effect that the discrimination information can be set is obtained.

[Form 6]
Further, in the exchange of the sixth aspect, the plurality of types of communication schemes include an LTE (Long Term Evolution) scheme for the configuration of any one of the first to fifth aspects,
The priority frequency discrimination information is an SPID (Subscriber) included in a control signal of S1-AP (S1 Application Protocol) which is a communication protocol used in communication between the exchange and the radio control apparatus in an LTE communication network. Profile ID for Radio Frequency Priority).

  With such a configuration, the SPID included in the S1-AP control signal can be used as the priority frequency discrimination information in the LTE communication network. As a result, the priority frequency including the discrimination information that can discriminate whether or not the small cell is preferentially located using the standard field without setting the carrier's own field for the standard signal. The effect that the discrimination information can be set is obtained.

[Form 7]
On the other hand, in order to achieve the above object, the exchange control program according to the seventh aspect of the present invention is configured to include a plurality of mobile communication networks respectively corresponding to a plurality of types of mobile communication systems, and communicate with mobile terminals. In a mobile communication system configured to include a large cell that is a cell having a relatively large possible area size, and a small cell whose size of the communicable area is a cell that is extremely smaller than the large cell, An exchange executed in a computer provided in an exchange having a radio control device under control of radio communication with the mobile terminal via the large cell and radio communication with the mobile terminal via the small cell A control program,
Location policy information, which is information for setting whether to preferentially reside in the small cell of the mobile terminal set in advance, is acquired from a subscriber information holding device provided in the mobile communication system. Zone policy information acquisition step,
Priority frequency determination information that is information for determining a frequency band of a cell corresponding to a communication method that the mobile terminal should be preferentially located in, and the area policy information acquired in the area policy information acquisition step A discrimination information setting step for setting priority frequency discrimination information including discrimination information capable of discriminating a frequency band of a cell to be preferentially located based on
A priority frequency discrimination signal transmission step for transmitting a priority frequency discrimination signal, which is a control signal including the priority frequency discrimination information set in the discrimination information setting step, to the radio network controller. It is characterized by that.
With such a configuration, when the program is read by the computer and the computer executes processing in accordance with the read program, the same operations and effects as those of the exchange described in the first mode can be obtained.

[Form 8]
In order to achieve the above object, the switch control method according to the eighth aspect of the present invention includes a plurality of mobile communication networks respectively corresponding to a plurality of types of mobile communication systems, and communicates with mobile terminals. In a mobile communication system configured to include a large cell that is a cell having a relatively large possible area size, and a small cell whose size of the communicable area is a cell that is extremely smaller than the large cell, An exchange control method for controlling an exchange having a radio control device under control of radio communication with the mobile terminal via the large cell and radio communication with the mobile terminal via the small cell. And
A subscriber information holding device provided in the mobile communication system with location policy information which is information for setting whether or not the exchange preferentially exists in the small cell of the mobile terminal set in advance The location policy information acquisition step acquired from
The switch receives priority frequency discrimination information that is information for discriminating a frequency band of a cell corresponding to a communication scheme that the mobile terminal should prevail in, and the presence policy information acquired in the location policy information acquisition step. A discrimination information setting step for setting priority frequency discrimination information including discrimination information capable of discriminating a frequency band of a cell to be preferentially located based on zone policy information;
The switch includes a priority frequency discrimination signal transmission step of transmitting a priority frequency discrimination signal, which is a control signal including the priority frequency discrimination information set in the discrimination information setting step, to the radio network controller. .
As a result, the same operation and effect as those of the form 1 switch can be obtained.

[Form 9]
In order to achieve the above object, the radio control apparatus according to the ninth embodiment of the present invention includes a plurality of mobile communication networks respectively corresponding to a plurality of types of mobile communication systems, and communicates with mobile terminals. In a mobile communication system configured to include a large cell that is a cell having a relatively large possible area size, and a small cell whose size of the communicable area is a cell that is extremely smaller than the large cell, A radio control apparatus for controlling radio communication with the mobile terminal via the large cell and radio communication with the mobile terminal via the small cell,
Priority frequency discrimination information that is information for discriminating a frequency band of a cell corresponding to a communication scheme that the mobile terminal should prevail from an exchange having the radio control device under control, and the mobile terminal Priority frequency including discriminating information that can be used to determine the frequency band of the cell that should preferentially be set, based on the location policy information that sets whether to preferentially exist in the small cell A priority frequency discrimination signal receiving unit that receives a priority frequency discrimination signal that is a control signal including discrimination information;
Based on priority frequency discrimination information included in the priority frequency discrimination signal received from the exchange, a frequency band discrimination unit that discriminates a frequency band of a cell corresponding to a communication method that the mobile terminal should prevail in, and
A search frequency designation signal transmission unit for transmitting a search frequency designation signal, which is a control signal including information for designating the frequency band determined by the frequency band discrimination unit as a search frequency band of the cell of the mobile terminal, to the mobile terminal; With
The search frequency designation signal transmission unit transmits the search frequency designation signal to the mobile terminal at a timing when the mobile terminal transitions to a standby state.
With such a configuration, it is possible to cause the mobile terminal to perform a small cell search after the mobile terminal transitions to the standby state, thereby preventing the packet communication from being forcibly disconnected. The effect that it can do is acquired.

[Form 10]
In order to achieve the above object, the mobile communication system according to the tenth aspect of the present invention is configured to include a plurality of mobile communication networks respectively corresponding to a plurality of types of mobile communication systems, and communicate with mobile terminals. A mobile communication system configured to include a large cell that is a cell having a relatively large possible area size and a small cell that is an extremely small cell having a size of the communicable area that is smaller than the large cell. And
A radio controller for controlling radio communication with the mobile terminal via the large cell and radio communication with the mobile terminal via the small cell, and an exchange having the radio controller under control thereof, A subscriber information holding device for holding subscriber information;
The subscriber information holding device is:
Resident policy that transmits to the switch, the visited policy information, which is information for setting whether or not the small cell of the mobile terminal is preferentially set in response to an acquisition request from the switch An information transmission unit,
The exchange is
A location policy information acquisition unit that acquires the location policy information from the subscriber information holding device;
Priority frequency discrimination information that is information for discriminating a frequency band of a cell corresponding to a communication method that the mobile terminal should prevail in, and the location policy information acquired by the location policy information acquisition unit, A discrimination information setting unit for setting priority frequency discrimination information including discrimination information capable of discriminating a frequency band to be preferentially located based on
A priority frequency discrimination signal transmission unit that transmits a priority frequency discrimination signal, which is a control signal including the priority frequency discrimination information set by the discrimination information setting unit, to the radio control device;
The wireless control device
Based on priority frequency discrimination information included in the priority frequency discrimination signal received from the exchange, a frequency band discrimination unit that discriminates a frequency band of a cell corresponding to a communication method that the mobile terminal should prevail in, and
A search frequency designation signal transmission unit for transmitting a search frequency designation signal, which is a control signal including information for designating the frequency band determined by the frequency band discrimination unit as a search frequency band of the cell of the mobile terminal, to the mobile terminal; It is characterized by having.
With such a configuration, the same operation and effect as those of the exchange of the first aspect can be obtained.

1 is a schematic configuration diagram of a mobile communication system 1 according to an embodiment. It is a functional block diagram of subscriber information server HSS concerning an embodiment. It is a figure which shows an example of the location policy information which concerns on embodiment. It is a functional block diagram of exchange MME / SGSN which concerns on embodiment. It is a figure which shows an example of the data table which shows the correspondence of the value of SPID and the communication method which the mobile terminal UE should prevail. It is a functional block diagram of the radio | wireless control apparatus eNB / IPRNC which concerns on embodiment. It is a figure which shows an example of the timing which the transmission part 33 of the radio base station eNB and radio | wireless control apparatus IPRNC which concerns on embodiment transmits a search frequency designation | designated signal. It is a functional block diagram of the mobile terminal UE which concerns on embodiment. (A) is a figure which shows an example of the initial location method at the time of setting location policy information to B mode, (b) is a figure which shows an example of the initial location method by special number transmission. It is a figure which shows an example of the memory | storage process of position registration area information. It is a sequence diagram which shows operation | movement of the mobile communication system 1 which concerns on the 1st operation example of this embodiment. It is a flowchart which shows an example of the process sequence of a SPID conversion process. It is a sequence diagram which shows operation | movement of the mobile communication system 1 which concerns on the 2nd operation example of this embodiment. It is a figure which shows the outline | summary of the flow of the signal in the guidance process to the 3G femtocell by the conventional special number transmission. It is a figure which shows a mode that it changes from the 3G macrocell by the conventional special number transmission to 3G femtocell. It is a figure which shows an example of the specific operation | movement sequence at the time of performing the special number transmission by the conventional menu operation. It is a figure which shows an example of the conventional operation | movement sequence which carries out the guidance (system guidance) spontaneously to the femtocell which has visited the mobile terminal UE in the past.

(First embodiment)
Embodiments of an exchange, an exchange control program, an exchange control method, a radio control apparatus, and a mobile communication system according to the present invention will be described below with reference to the drawings. Here, FIG. 1 to FIG. 13 are diagrams showing embodiments of an exchange, an exchange control program, an exchange control method, a radio control apparatus, and a mobile communication system according to the present invention.
(1) Configuration (1-1) Configuration of Mobile Communication System 1 First, the configuration of the mobile communication system 1 will be described with reference to FIG. FIG. 1 is a block diagram showing a schematic configuration of the mobile communication system 1.
The mobile communication system 1 according to the present embodiment is a system including a W-CDMA communication network, which is one 3G method, and an LTE mobile communication network.
Specifically, as shown in FIG. 1, the mobile communication system 1 according to the present embodiment includes a W-CDMA exchange SGSN and a W-CDMA radio controller IPRNC.

The mobile communication system 1 further includes a Macro BTS (hereinafter referred to as a macro BTS) that forms a W-CDMA macro cell, a femto BTS that forms a W-CDMA femto cell, It is comprised including.
The mobile communication system 1 further includes an LTE exchange MME, and a radio base station eNB that is an apparatus that integrates a base station and a radio controller that form LTE and W-CDMA macro cells. The The mobile communication system 1 is further configured to include a femto radio base station HeNB that is an apparatus in which a base station that forms a femto cell of an LTE scheme and a W-CDMA scheme and a radio control apparatus are integrated.

Hereinafter, a W-CDMA macro cell is referred to as a 3G macro cell, and a W-CDMA femto cell is referred to as a 3G femto cell. Further, an LTE macro cell is referred to as an LTE macro cell, and an LTE femto cell is referred to as an LTE femto cell.
The mobile communication system 1 further includes a subscriber information server HSS (Home Subscriber Server) which is a subscriber information holding device connected to the W-CDMA exchange SGSN and the LTE exchange MME.

In this embodiment, the femto BTS is connected to the core network via an HNB-GW (Home Node B-Gateway) that is a gateway device for connecting the femto BTS (HNB (Home Node B)) to the core network. It is good also as a structure to connect. In the present embodiment, the femto radio base station HeNB is connected to the core network via a HeNB-GW (Home EUTRAN Node B-Gateway) that is a gateway device for connecting the femto radio base station HeNB to the core network. It is good also as composition to do.
FIG. 1 shows only the components according to the present embodiment among the components configuring a mobile communication system including a W-CDMA communication network and an LTE mobile communication network. Yes.

(1-2) Example of Functional Configuration of Subscriber Information Server HSS Next, an example of the functional configuration of the subscriber information server HSS according to the present embodiment will be described based on FIG. FIG. 2 is a functional block diagram of the subscriber information server HSS according to the present embodiment.
As shown in FIG. 2, the subscriber information server HSS includes a receiving unit 10, a subscriber profile acquisition unit 11, a subscriber information management unit 12, a subscriber information update unit 13, and a transmission unit 14. Consists of.
The receiving unit 10 receives a control signal from the exchange MME or the exchange SGSN, or receives a subscriber profile update request signal or the like from a cascon server (not shown) that provides a customer control function to the mobile terminal UE. Is configured to do.

Specifically, the receiving unit 10, for example, receives an “Update GPRS Location” signal (location information update signal) transmitted by the W-CDMA exchange SGSN or an “Update Location Request” transmitted by the LTE exchange MME. A control signal such as a signal (position information update signal) is received.
The customer control function is one of the functions of the service, and is a function that allows the user to change various items set in the initial stage at any time. For example, from the mobile terminal UE, setting of a connected user, confirmation of administrator registration contents, confirmation of usage status (log report), password change, and the like can be performed on a website.

In the present embodiment, the user can change the location policy information for the femtocell of the user terminal UE using the customer control function.
Here, FIG. 3 is a diagram showing an example of the in-zone policy information according to the present embodiment.
As shown in FIG. 3, the location policy information in the present embodiment is set in three modes such as an A mode, a B mode, and a C mode. Specifically, the A mode is a mode in which the LTE femto cell is not preferentially searched. That is, when the A mode is set, the mobile terminal UE is caused to perform a normal cell search process according to the SPID value described later. The B mode is a mode for preferentially searching for all LTE femtocells. That is, when the B mode is set, the cell search process is performed so that the mobile terminal UE preferentially searches for the LTE femto cell in any macro cell. The C mode is a mode in which LTE femto cells are preferentially searched only when they are located in a macro cell that covers LTE femto cells that have been in the past. That is, when the C mode is set, the LTE femto cell is preferentially given to the mobile terminal UE only when the mobile terminal UE is in a macro cell that covers an LTE femto cell that has been in the past. The cell search process is performed so as to search.

  Returning to FIG. 2, the subscriber profile acquisition unit 11 acquires a subscriber profile from the subscriber information management unit 12 in accordance with a control signal from the exchange MME or the exchange SGSN. The acquired subscriber profile is output to the transmission unit 14. Further, the subscriber profile acquisition unit 11 receives a control signal including IMEISV (International Mobile Station Equipment Identity) or IMEI (International Mobile Station Equipment Identity) which is an identifier of the mobile terminal UE from the exchange MME or the exchange SGSN. In response to the reception, the subscriber information management unit 12 acquires specification information of the mobile terminal UE corresponding to IMEISV or IMEI (hereinafter referred to as IMEI without distinction). And it is comprised so that the acquired specification information may be output to the transmission part 14. FIG. In the present embodiment, the specification information indicates whether the mobile terminal UE specified by IMEI is a terminal that supports the LTE scheme or a terminal that supports the CSFB (Circuit Switched Fallback) function. Information.

  The subscriber information management unit 12 is configured to manage subscriber information of each mobile terminal UE. For example, the subscriber information management unit 12 manages user contract information (including contract information related to the use of the femtocell) and location information (location registration area) of the mobile terminal UE as subscriber information of each mobile terminal UE. It is configured to manage a subscriber profile such as an address of an exchange that is used and a secret key for authentication. Note that the contract information related to the use of the femtocell is information on a user who has registered the use of the femtocell. The registration information of the 3G femtocell provided by the conventional femtoBTS and the femto radio base station HeNB 3G femtocell and LTE femtocell (dual femtocell) usage registration information provided in FIG.

The subscriber information management unit 12 is further configured to manage, as a subscriber profile, the location policy information of each mobile terminal UE and the identification information of a macro cell that covers a femto cell that has been in the past. .
Specifically, the subscriber information management unit 12 covers the 3G femtocell where the mobile terminal UE is located when the B mode or the C mode is set as the located policy information (when overlaying on the 3G femtocell) The HomeLAC that is the identification information of the 3G macro cell is stored and held. Further, the subscriber information management unit 12 stores and holds a TAC (Tracking Area Code) (hereinafter referred to as HomeTAC) that is identification information of an LTE macro cell that covers the LTE femto cell (also referred to as overlaying the LTE femto cell). It is configured as follows. In the present embodiment, the subscriber information management unit 12 is configured to store and hold a preset number in order from a new one of the HomeLAC or HomeTAC of the macrocell that covers the femtocell that has been in the past. Therefore, when a new HomeLAC or HomeTAC is received in a state where the stored HomeLAC or HomeTAC has reached the preset upper limit number, the oldest one is deleted in order. In addition, since the radio base station eNB is configured to form both the LTE macro cell and the 3G macro cell, when the mobile terminal UE is located in one of the macro cells, the other location registration area It is also possible to know the information. In the present embodiment, the subscriber information management unit 12 stores and holds both HomeLAC and HomeTAC when the macro cell formed by the radio base station eNB is a cover cell.

  Therefore, in this embodiment, when the C mode is set as the in-zone policy information, the LAC or TAC cover that matches the preset number of HomeLACs or HomeTACs stored and held by the subscriber information management unit 12 Only when the mobile terminal UE is located in the cell, the mobile terminal UE is caused to search the LTE femto cell preferentially. In addition, the conventional system guidance is executed in the mobile terminal UE registered for use of the conventional 3G femtocell.

  When the subscriber information update unit 13 acquires the location policy update instruction information included in the received signal via the reception unit 10, the site policy information included in the corresponding subscriber profile in the subscriber information management unit 12. Is updated to contents corresponding to the update instruction information. Furthermore, when the subscriber information update unit 13 acquires the HomeLAC or HomeTAC included in the control signal related to the update of the location information via the reception unit 10, it is included in the corresponding subscriber profile in the subscriber information management unit 12. It is configured to update HomeLAC or HomeTAC.

The transmission unit 14 transmits an “Update Location Answer” signal (location information update response signal) to the exchange MME, or transmits an “Insert Subscriber Data” signal (subscriber information transmission signal) to the exchange SGSN, and receives the response. After that, an “Update GPRS Location Ack” signal (position information update response signal) is transmitted to the exchange SGSN.
FIG. 2 shows only the components according to the present embodiment of the subscriber information server HSS.

Although not shown, the subscriber information server HSS includes a computer system for executing the above functions using software and executing software for controlling hardware necessary for realizing the functions. Yes.
Such a computer system includes a central processing unit (CPU), a random access memory (RAM), a read only memory (ROM), an input / output interface (I / F), and a bus. The CPU, RAM, ROM, and input / output I / F are connected to a bus, and data can be transmitted and received between these connected devices via the bus. Although not shown, the subscriber information server HSS includes a storage device, a display device, an input device, and a communication device connected via an input / output I / F.

(1-3) Functional Configuration Examples of Exchange MME and Exchange SGSN Next, an example of functional configurations of the exchange MME and the exchange SGSN according to the present embodiment will be described based on FIG. FIG. 4 is a functional block diagram of the exchange MME and the exchange SGSN according to the present embodiment.
As shown in FIG. 4, the exchange MME and the exchange SGSN include a reception unit 20, a subscriber profile acquisition unit 21, a subscriber profile management unit 22, a visited macrocell information acquisition unit 23, and a terminal specification information acquisition unit 24. A priority frequency discrimination information setting unit 25, an SPID management unit 26, and a transmission unit 27.

The receiving unit 20 of the exchange MME is configured to receive various control signals from the radio base station eNB and receive various control signals from the subscriber information server HSS.
Specifically, the receiving unit 20 of the exchange MME receives an “Initial UE Message” signal that is an S1-AP control signal from the radio base station eNB, an “Update Location Answer” signal, etc. from the subscriber information server HSS. Or is configured to receive.

The receiving unit 20 of the exchange SGSN is configured to receive various control signals from the radio network controller IPRNC and receive various control signals from the subscriber information server HSS.
Specifically, the receiving unit 20 of the exchange SGSN receives an “Initial UE Message” signal that is a control signal of the RANAP protocol from the radio network controller IPRNC, or receives an “Insert Subscriber Data” signal from the subscriber information server HSS, It is configured to receive an “Update GPRS Location Ack” signal or the like.

The subscriber profile acquisition unit 21 of the exchange MME and the exchange SGSN obtains the subscriber profile included in the control signal from the control signal including the subscriber profile received from the subscriber information server HSS in the reception unit 20. The acquired subscriber profile is output to the subscriber profile management unit 22.
The subscriber profile management unit 22 of the exchange MME and the exchange SGSN is configured to manage the subscriber profile acquired by the subscriber profile acquisition unit 21. Specifically, the subscriber profile management unit 22 of the exchange MME and the exchange SGSN stores the acquired subscriber profile in a storage device (not shown), and stores the subscriber profile in the stored subscriber profile in response to a request from each component. Various types of information included are read from the storage device and output to the requesting component. The subscriber profile managed by the subscriber profile management unit 22 includes the location policy information and the HomeTAC and HomeLAC.

The in-zone macro cell information acquisition unit 23 of the exchange MME includes, in the reception unit 20, the TAC that is the location registration area identification information corresponding to the LTE macro cell in which the mobile terminal UE is located, received from the radio base station eNB. The TAC included in the control signal is acquired from the control signal. Then, the acquired TAC is output to the priority frequency discrimination information setting unit 25.
In addition, the in-zone macrocell information acquisition unit 23 of the exchange SGSN receives LAC, which is received from the radio network controller RNC, in the receiving unit 20, and is LAC that is the location registration area identification information corresponding to the 3G macrocell in which the mobile terminal UE is in the area. LAC included in the control signal is obtained from the control signal including Then, the acquired LAC is output to the priority frequency discrimination information setting unit 25.

  The terminal specification information acquisition unit 24 of the exchange MME receives the control signal from the control signal received from the radio base station eNB by the reception unit 20 in the authentication and concealment processing for the mobile terminal UE performed after receiving the control signal including the TAC. The IMEI included in is acquired. And it is comprised through the transmission part 27 to transmit to the subscriber information server HSS the control signal containing the acquisition request for acquiring the specification information of the mobile terminal UE specified by acquired IMEI.

  Also, the terminal specification information acquisition unit 24 of the exchange SGSN receives the control signal from the control signal received from the RNC by the reception unit 20 in the authentication and concealment processing for the mobile terminal UE performed after receiving the control signal including the LAC. Get the included IMEI. And it is comprised through the transmission part 27 to transmit to the subscriber information server HSS the control signal containing the acquisition request for acquiring the specification information of the mobile terminal UE specified by acquired IMEI.

The terminal specification information acquisition unit 24 of the exchange MME and the exchange SGSN acquires terminal specification information included in the control signal from the control signal including the terminal specification information received from the subscriber information server HSS in the reception unit 20. The acquired terminal specification information is output to the priority frequency discrimination information setting unit 25.
The priority frequency discrimination information setting unit 25 of the exchange MME and the exchange SGSN performs SPID derivation processing based on the terminal specification information after obtaining the terminal specification information. Specifically, the priority frequency discrimination information setting unit 25 of the exchange MME and the exchange SGSN is preferentially located from the SPID management unit 26 corresponding to the terminal specification information from the data table managed by the SPID management unit 26. The SPID value set in advance for the communication method to be acquired is acquired.
Here, FIG. 5 is an example of a data table showing a correspondence relationship between the SPID value according to the present embodiment and a communication method (also referred to as priority RAT (Radio Access Technology)) that the mobile terminal UE should prevail in. FIG.

  As shown in FIG. 5, in the SPID value, “1” corresponds to 3G priority (3G> LTE), and “2” corresponds to LTE priority (LTE> 3G). Specifically, “1” indicates that the cell to which the mobile terminal UE should prevail is a 3G system (W-CDMA system in this embodiment) cell. Further, “2” indicates that the cell to which the mobile terminal UE should prevail is an LTE cell.

As shown in FIG. 5, in the SPID value, “3” corresponds to LTE Femto → 3G → LTE macro, and “4” corresponds to LTE Femto → LTE macro → 3G. Specifically, “3” indicates that the cell to which the mobile terminal UE should be located first is the LTE femto cell, and the cell that should be located next is the 3G cell, This indicates that the cell to be preferentially located is the LTE macro cell. Also, “4” indicates that the cell that the mobile terminal UE should be in the highest priority is the LTE femto cell, the cell that should be in the next priority is the LTE macro cell, and is the next priority. This indicates that the cell to be serviced is a 3G cell.
In the present embodiment, the priority frequency discrimination information setting unit 25 of the exchange MME and the exchange SGSN acquires the SPID value corresponding to the terminal specification information from the data table shown in FIG.

In the present embodiment, the SPID values derived from the terminal specification information of the mobile terminal UE are “1” and “2”. As described above, processing for deriving the SPID value corresponding to either 3G priority or LTE priority has been conventionally performed based on terminal specification information (particularly, whether or not CSFB is capable).
For example, when it is determined from the terminal specification information that the mobile terminal UE has the CSFB function, the priority frequency discrimination information setting unit 25 of the exchange MME and the exchange SGSN obtains “1” as the SPID value from the data table. It is possible to configure. Further, the priority frequency discrimination information setting unit 25 of the exchange MME and the exchange SGSN, for example, determines from the data table that the mobile terminal UE is a terminal compatible with the LTE scheme having no CSFB function. , “2” can be obtained as the SPID value.
In addition, the priority frequency discrimination information setting unit 25 of the exchange MME and the exchange SGSN is not limited to such a configuration, and when it is determined that the mobile terminal UE is compatible with the LTE system, regardless of the presence or absence of the CSFB function, the SPID It is also possible to configure to obtain “2” as a value.

  In the present embodiment, the priority frequency discrimination information setting unit 25 of the exchange MME and the exchange SGSN acquires “1” as the SPID value when the mobile terminal UE determines that the CSFB function is provided, and the mobile terminal UE has the CSFB function. When it is determined that the terminal is a terminal compatible with the LTE system that does not have a SPID value, “2” is acquired as the SPID value.

  Next, the priority frequency discrimination information setting unit 25 of the exchange MME and the exchange SGSN acquires the in-zone policy information managed by the subscriber profile management unit 22. When the priority frequency discrimination information setting unit 25 of the exchange MME and the exchange SGSN determines that the acquired in-zone policy information is the A mode, the acquired SPID value “1” or “2” is directly sent to the transmission unit 27. Output.

On the other hand, if the priority frequency discrimination information setting unit 25 of the exchange MME and the exchange SGSN determines that the acquired in-zone policy information is in the B mode, “1” is set to “1” when the acquired SPID value is “1”. When the acquired SPID value is “2”, “2” is converted to “4”. Then, the converted SPID value is output to the transmitter 27.
If the priority frequency discrimination information setting unit 25 of the exchange MME determines that the acquired in-zone policy information is in the C mode, it acquires all HomeTACs managed by the subscriber profile management unit 22. Then, it is determined whether or not the TAC acquired from the macro cell information acquisition unit 24 matches the HomeTAC. This determination process is performed for all HomeTACs. If the priority frequency discrimination information setting unit 25 of the exchange MME determines that there is a HomeTAC that matches the acquired TAC, if the acquired SPID value is “1”, it converts “1” to “3” and acquires it. If the SPID value is “2”, “2” is converted to “4”. Then, the converted SPID value is output to the transmitter 27.

  Further, if the priority frequency discrimination information setting unit 25 of the exchange SGSN determines that the acquired in-zone policy information is the C mode, it acquires the HomeLAC managed by the subscriber profile management unit 22. Then, it is determined whether the LAC acquired from the macro cell information acquisition unit 24 and the HomeLAC match. This determination process is performed for all HomeLACs. If the priority frequency discrimination information setting unit 25 of the exchange SGSN determines that there is a HomeLAC that matches the acquired LAC, if the acquired SPID value is “1”, it converts “1” to “3” and acquires it. If the SPID value is “2”, “2” is converted to “4”. Then, the converted SPID value is output to the transmitter 27.

In response to a request from the terminal specification information acquisition unit 24, the transmission unit 27 of the exchange MME and the exchange SGSN sends an acquisition request for acquiring the specification information of the mobile terminal UE specified by IMEI to the subscriber information server HSS. It is configured to transmit a control signal including.
Furthermore, the transmission unit 27 of the exchange MME is configured to transmit a control signal including the SPID value acquired from the priority frequency discrimination information setting unit 25 to the radio base station eNB. Specifically, the acquired SPID value is set in the SPID standard field of the S1-AP standard control signal defined by 3GPP. In the present embodiment, the transmission unit 27 of the exchange MME sets the acquired SPID value in the SPID field of the “Initial Context Setup Request” signal of the S1-AP, and includes the “Initial Context Setup” including the SPID value. A “Request” signal is transmitted to the radio base station eNB.

  Further, the transmission unit 27 of the exchange SGSN is configured to transmit a control signal including the SPID value acquired from the priority frequency discrimination information setting unit 25 to the radio network controller IPRNC. Specifically, the acquired SPID value is set in the SPID standard field of the standard control signal of the RANAP protocol defined by 3GPP. In the present embodiment, the transmission unit 27 of the exchange SGSN sets the acquired SPID value in the SPID field of the “Common ID” signal of the RANAP protocol, and wirelessly transmits the “Common ID” signal including the SPID value. Transmit to control device RNC.

  In the present embodiment, the exchange MME performs the above SPID conversion process when receiving the “Attach Request” signal from the radio base station eNB and when returning from the “Preservation” state (from the radio base station eNB to Service Request and (When receiving an “Initial UE Message” signal including TAC information).

  Further, in the present embodiment, the exchange SGSN receives the process of converting the SPID derived based on the in-zone policy information when receiving the “Initial UE Message” signal including the Attach Request and LAC information from the radio network controller IPRNC. It is configured to perform an “Initial UE Message” signal including RAU Request and LAC information from the radio network controller IPRNC.

FIG. 4 shows only components according to the present embodiment among the exchange MME and the exchange SGSN.
In addition, although not shown, the exchange MME and the exchange SGSN include a computer system for executing the above functions using software and executing software for controlling hardware necessary for realizing the functions. Yes.

  Such a computer system includes a central processing unit (CPU), a random access memory (RAM), a read only memory (ROM), an input / output interface (I / F), and a bus. The CPU, RAM, ROM, and input / output I / F are connected to a bus, and data can be transmitted and received between these connected devices via the bus. Further, although not shown, the exchange MME and the exchange SGSN include a storage device, a display device, an input device, and a communication device connected via an input / output I / F.

(1-4) Functional Configuration Example of Radio Base Station eNB and Radio Control Apparatus IPRNC Next, an example of functional configuration of the radio base station eNB and radio control apparatus IPRNC according to the present embodiment will be described based on FIG. FIG. 6 is a functional block diagram of the radio base station eNB and the radio network controller IPRNC according to the present embodiment.
As illustrated in FIG. 6, the radio base station eNB and the radio network controller IPRNC include a reception unit 30, a priority frequency determination unit, a search frequency management unit 32, and a transmission unit 33.
The receiving unit 30 of the radio base station eNB is configured to receive various control signals such as an “Initial Context Setup Request” signal in which the SPID value is set from the exchange MME.

The receiving unit 30 of the radio network controller IPRNC is configured to receive various control signals such as a “Common ID” signal including the SPID value from the exchange SGSN.
Based on the SPID value included in the “Initial Context Setup Request” signal received by the receiving unit 30, the priority frequency determining unit 31 of the radio base station eNB determines the cell of the communication scheme that the mobile terminal UE should prevail in A frequency band (hereinafter referred to as a priority frequency band) is determined.

Further, the priority frequency determination unit 31 of the radio network controller IPRNC is configured to determine the priority frequency band based on the SPID value included in the “Common ID” signal received by the reception unit 30.
Specifically, when the priority frequency determination unit 31 of the radio base station eNB and the radio network controller IPRNC determines that the SPID value is “1”, the priority frequency band is determined to be a frequency band of a 3G cell. Is configured to do.

Also, if the priority frequency determination unit 31 of the radio base station eNB and the radio network controller IPRNC determines that the SPID value is “2”, the priority frequency band is determined to be the frequency band of the LTE cell. It is configured.
In addition, when the priority frequency determination unit 31 of the radio base station eNB and the radio network controller IPRNC determines that the SPID value is “3”, the priority frequency band is the frequency band of the LTE femto cell in descending order of priority → The frequency band of the 3G cell is determined to be the frequency band of the LTE macro cell.

Also, when the priority frequency determination unit 31 of the radio base station eNB and the radio network controller IPRNC determines that the SPID value is “4”, the priority frequency band is the frequency band of the LTE femto cell in descending order of priority → The frequency band of the LTE macro cell is determined to be the frequency band of the 3G cell.
The priority frequency determination unit 31 of the radio base station eNB and the radio network controller IPRNC acquires frequency band information corresponding to the determined priority frequency band (hereinafter referred to as priority frequency band information) from the search frequency management unit 32. The obtained priority frequency band information is output to the transmission unit 33.

  The search frequency management unit 32 of the radio base station eNB and the radio network controller IPRNC manages information on the frequency band of the 3G macro cell, the frequency band of the LTE macro cell, the frequency band of the LTE femto cell, and the frequency band of the 3G femto cell. It is configured. Specifically, the search frequency management unit 32 of the radio base station eNB and the radio network controller IPRNC stores and holds information on various frequency bands in a storage device (not shown), and is necessary according to a request from the priority frequency determination unit 31 It is configured to read out information on the appropriate frequency band from the storage device and output the information to the priority frequency determination unit 31.

The radio base station eNB and the transmission unit 33 of the radio network controller IPRNC are configured to transmit various control signals to the mobile terminal UE. When the transmission unit 33 of the radio base station eNB and the radio network controller IPRNC of the present embodiment acquires the priority frequency band information from the priority frequency determination unit 31, the mobile terminal transmits a search frequency designation signal that is a control signal including the priority frequency band information. It is configured to transmit to the UE. In addition, the transmission unit 33 of the radio base station eNB and the radio network controller IPRNC of the present embodiment transmits a search frequency designation signal to the mobile terminal UE at a timing when the mobile terminal UE shifts to a standby state (transitions to the Idle state). Is configured to do.
Here, FIG. 7 is a diagram illustrating an example of timing at which the transmission unit 33 transmits the search frequency designation signal.

In the present embodiment, the search frequency designation signal is transmitted at the timing of the Idle transition at the location indicated by “◯” in FIG. 7, and the timing for the Idle transition at the location indicated by “X” in FIG. However, the search frequency designation signal is not transmitted.
As illustrated in FIG. 7, the transmission unit 33 of the radio base station eNB transmits a search frequency designation signal at a timing when the state transitions to the Idle state after the Attach process and a timing when the state transitions to the Idle state after the return process from the Preservation state. It has a configuration.

Further, as shown in FIG. 7, the transmission unit 33 of the radio network controller IPRNC transmits a search frequency designation signal at the timing of transition to the Idle state after the RAU process and the timing of transition to the Idle state after the Attach process. It has become.
Here, the Attach process is a position registration process performed after the mobile terminal UE is powered on. In addition, the preservation state means that when the mobile terminal UE is in the packet connection state and the non-communication state continues for a certain time or longer, only the connection in the radio section is released and the mobile terminal UE and the core network side logically connect the packet connection state. It is a state to maintain. The RAU process is a position registration update process performed when the mobile terminal UE in a power-on state moves to a 3G macro cell in a position registration area different from the current one. The TAU process is a location registration update process performed when the mobile terminal UE in a power-on state moves to an LTE macro cell under the management of the exchange MME different from the current one.

  Specifically, in the LTE communication network, a process of transmitting an “Initial Context Setup Request” signal from the exchange MME to the radio base station eNB occurs in the Attach process and the return process from the Preservation state. Therefore, the radio base station eNB can acquire the SPID by executing these processes. Therefore, in this embodiment, the transmission unit 33 of the radio base station eNB includes the priority frequency band information corresponding to the SPID after the conversion process at the timing of the Idle transition after the Attach process and after the return process from the Preservation state. A search frequency designation signal is configured to be transmitted to the mobile terminal UE.

  On the other hand, in the LTE communication network, in the TAU process, the process that crosses the location registration area by handover (HO), and the process that changes the location policy information via the cascon server, the exchange MME sends the radio base station eNB to “ The process of transmitting the “Initial Context Setup Request” signal does not occur. Therefore, even if these processes are executed, the radio base station eNB cannot acquire the SPID. Therefore, in this embodiment, the transmission unit 33 of the radio base station eNB performs Idle transition after TAU processing, after processing that crosses the location registration area by handover, and after processing that changes the location policy information via the cascon server. At this timing, the process of transmitting the search frequency designation signal including the priority frequency band information corresponding to the SPID after the conversion process to the mobile terminal UE is not performed.

  In the 3G communication network, a process of transmitting a “Common ID” signal from the exchange SGSN to the radio network controller IPRNC occurs in the Attach process and the RAU process. Therefore, by executing these processes, the radio network controller IPRNC can acquire the SPID. Therefore, in this embodiment, the transmission unit 33 of the radio network controller IPRNC performs a search frequency designation signal including priority frequency band information corresponding to the SPID after the conversion process at the timing of the Idle transition after the Attach process and the RAU process. Is transmitted to the mobile terminal UE.

  On the other hand, in the return processing from the preservation state in the 3G communication network, a process of transmitting a “Common ID” signal from the exchange SGSN to the radio network controller IPRNC occurs. However, the TAU process is always performed before the return process from the Preservation state is performed. Therefore, in the present embodiment, the transmission unit 33 of the radio network controller IPRNC performs a search frequency designation signal including priority frequency band information corresponding to the SPID after the conversion process at the timing of the Idle transition after the return process from the Preservation state. Is configured not to perform the process of transmitting to the mobile terminal UE. In addition, you may comprise so that the process which transmits the search frequency designation | designated signal containing the priority frequency band information corresponding to SPID after the said conversion process to the mobile terminal UE may be implemented not only in this structure.

  Also, in a 3G communication network, a “Common ID” signal is transmitted from the exchange SGSN to the radio network controller IPRNC in the process of crossing the location registration area by handover and the process of changing the location policy information via the Cascon server. Processing does not occur. Therefore, in these processes, the radio network controller IPRNC cannot acquire the SPID. Therefore, in the present embodiment, the transmission unit 33 of the radio network controller IPRNC performs the above-described Idle transition timing after processing that crosses the location registration area by handover and after processing that changes the location policy information via the cascon server. The process of transmitting the search frequency designation signal including the priority frequency band information corresponding to the SPID after the conversion process to the mobile terminal UE is not performed.

  Here, when the mobile terminal UE shifts to the standby state, a process for releasing the RRC connection is always performed. Therefore, in the present embodiment, the priority frequency band information and the priority of the frequency band corresponding to each communication method and cell type are transmitted at the timing of transmitting the “RRC Connection Release” signal that is an RRC connection release signal to the mobile terminal UE. A control signal including information (hereinafter referred to as priority information) to be transmitted is transmitted.

  Specifically, the radio base station eNB and the transmission unit 33 of the radio network controller IPRNC add priority frequency band information and priority information (Cell Reselection Priority) to “idle Mode Mobility Control Info” which is a data field of the “RRC Connection Release” signal. ) Is set. Then, the “RRC Connection Release” signal after the setting is transmitted as a search frequency designation signal to the mobile terminal UE.

For example, when the SPID values are “3” and “4”, the priority information is information in which three levels of priority are set for the priority frequency band information. That is, when the SPID value is “3”, the frequency band of the LTE femto cell is set to the highest priority, the frequency band of the 3G cell is set to the next highest priority, and the frequency band of the LTE macro cell is set to the lowest priority. Set to degrees. On the other hand, when the SPID value is “4”, the frequency band of the LTE femto cell is set to the highest priority, the frequency band of the LTE macro cell is set to the next highest priority, and the frequency band of the 3G system cell is set to the lowest priority. Set to degrees.
FIG. 6 shows only the components according to the present embodiment among the radio base station eNB and the radio network controller IPRNC.

In addition, although not shown, the radio base station eNB and the radio network controller IPRNC implement the above functions using software, and a computer for executing software that controls hardware necessary for realizing each function Has a system.
Such a computer system includes a central processing unit (CPU), a random access memory (RAM), a read only memory (ROM), an input / output interface (I / F), and a bus. The CPU, RAM, ROM, and input / output I / F are connected to a bus, and data can be transmitted and received between these connected devices via the bus. Although not shown, the radio base station eNB and the radio network controller IPRNC include a storage device, a display device, an input device, and a communication device connected via an input / output I / F.

(1-5) Functional Configuration Example of Mobile Terminal UE Next, an example of a functional configuration of the mobile terminal UE according to the present embodiment will be described based on FIG. FIG. 8 is a functional block diagram of the mobile terminal UE having the CSFB function according to the present embodiment.
As shown in FIG. 8, the mobile terminal UE includes a receiving unit 40, a cell search unit 41, a search frequency management unit 42, a special number transmission unit 43, a located area policy setting unit 44, and a transmission unit 45. It is configured to include.
The receiving unit 40 is configured to receive various control signals from the radio base station eNB, the femto radio base station HeNB, the macro BTS, and the femto BTS. In the present embodiment, the receiving unit 40 is configured to receive a search frequency designation signal (in this embodiment, an “RRC Connection Release” signal) from the radio base station eNB and the macro BTS (radio control apparatus IPRNC). Yes.

  The cell search unit 41 is configured to perform a cell search based on the priority frequency band information and priority information managed by the search frequency information management unit 42. When the mobile terminal UE determines that a corresponding cell is found by cell search, the mobile terminal UE transitions to a cell with the best connection condition (for example, a cell with the smallest propagation loss) among the found cells (moving in the area). It is configured.

  When the cell search unit 41 acquires information corresponding to the SPID value “3” or “4” as the priority frequency band information and the priority information, the LTE femto cell has the highest priority in the currently located macro cell. And search. This cell search is performed for all frequency bands corresponding to the LTE femto cell included in the priority frequency band information. If it is determined that an LTE femto cell is found by this cell search, the mobile terminal UE disconnects from the currently located macro cell and moves to the found LTE femto cell. In addition, the cell search part 41 performs the following cell search processes according to the value of corresponding SPID, when an LTE femto cell is not found.

  If the LTE femtocell is not found, the cell search unit 41, if the priority frequency band information and the priority information managed by the search frequency information management unit 42 are information corresponding to the SPID value “3”, Next, a 3G cell is searched based on frequency band information of the 3G cell (for example, spreading codes of neighboring 3G macro cells). If the cell search unit 41 determines that a 3G cell has not been found by this cell search, the cell search unit 41 then searches for the LTE macro cell based on the LTE macro cell frequency band information (for example, the spreading code of the surrounding LTE macro cell).

On the other hand, if no LTE femto cell is found, the cell search unit 41 determines that the priority frequency band information managed by the search frequency information management unit 42 is information corresponding to the SPID value “4”. The LTE macro cell is searched based on the frequency band information of the LTE macro cell. If the cell search unit 41 determines that the LTE macro cell is not found by this cell search, the cell search unit 41 searches for a 3G cell based on the frequency band information of the 3G cell.
If the cell search unit 41 determines that the priority frequency band information and the priority information managed by the search frequency information management unit 42 are information corresponding to the SPID value “1”, the cell search unit 41 selects a 3G cell. Search with priority. If no 3G cell is found, the cell search unit 41 next searches for an LTE cell.

On the other hand, when the cell search unit 41 determines that the priority frequency band information managed by the search frequency information management unit 42 is information corresponding to the SPID value “2”, the cell search unit 41 preferentially searches for the LTE cell. To do. In addition, when the LTE cell is not found, the cell search unit 41 searches for a 3G cell.
The search frequency information management unit 42 is configured to manage priority frequency band information and priority information included in the search frequency designation signal received by the reception unit 40. Specifically, the search frequency information management unit 42 stores and holds priority frequency band information included in the search frequency designation signal in a storage device (not shown). Then, in response to an acquisition request from the cell search unit 41, the priority frequency band information and the priority information are read from the storage device, and the read priority frequency band information and the priority information are output to the cell search unit 40. ing.

Further, the search frequency information management unit 42 receives the priority frequency band information and the priority information stored in the storage device each time a search frequency designation signal is received by the reception unit 40, and newly receives the search frequency designation. The priority frequency information and the priority information included in the signal are updated.
The special number transmission unit 43 is configured to transmit a specific number input to the user via an operation unit (not shown) or to transmit a specific number by a menu operation via the operation unit (not shown) of the user. .

  The in-zone policy setting unit 44 includes information on the mode selected by the user from among the three modes (A, B, and C) shown in FIG. 3 in response to the menu operation via the operation unit (not shown) of the user. A location policy setting signal that is a control signal is configured to be transmitted to the Cascon server via the transmission unit 45. Thereby, the location policy information included in the subscriber profile of the subscriber information server HSS is updated via the Cascon server. The initial value of the in-zone policy information can be set, for example, by the communication carrier out of the modes A to C.

The transmission unit 45 transmits various control signals to the radio base station eNB, the femto radio base station HeNB, the macro BTS, and the femto BTS. In the present embodiment, the transmission unit 45 is configured to transmit a control signal including a specific number, a control signal including in-zone policy information, and the like.
Although not shown, the mobile terminal UE includes a computer system for realizing the functions described above using software and executing software for controlling hardware necessary for realizing the functions.

Such a computer system includes a central processing unit (CPU), a random access memory (RAM), a read only memory (ROM), an input / output interface (I / F), and a bus. The CPU, RAM, ROM, and input / output I / F are connected to a bus, and data can be transmitted and received between these connected devices via the bus. Although not shown, the mobile terminal UE includes a storage device, a display device, an input device, and a communication device connected via an input / output I / F.
Further, the configuration has been described by taking the mobile terminal UE having the CSFB function as an example. However, in the mobile communication system 1 according to the present embodiment, in addition to the mobile terminal having the CSFB function, mobile terminals supporting only the LTE scheme are also mixed. .

(2) About the initial location method to the femtocell Next, an example of the initial location method to the femtocell of the mobile terminal UE in this embodiment is demonstrated based on FIG. FIG. 9A is a diagram showing an example of the initial location method when the location policy information is set to the B mode, and FIG. 9B is a diagram showing an example of the initial location method by calling a special number. .
As a first initial location method, there is a method of setting the location policy to the B mode.
When the in-zone policy information is set to the B mode, as described above, the LTE femto cell is searched with the highest priority regardless of the in-zone history of the femto cell. Therefore, as shown in FIG. 9 (a), when there is an LTE femtocell that can be located in the currently existing 3G macro cell or LTE macro cell, the mobile terminal UE preferentially finds this femto cell. Move in the area. As a result, the HomeLAC of the 3G macro cell and the HomeTAC of the LTE macro cell covering the LTE femtocell located in the area are transmitted to the subscriber information server HSS via the exchange MME or the exchange SGSN. Then, the subscriber information server HSS stores the 3G macro cell covering the located LTE femtocell and the HomeLAC and HomeTAC of the LTE macrocell.

In addition, as a second initial location method, there is a method (existing function) in which a special number is transmitted from a mobile terminal UE having a CSFB function for which dual femto usage registration is performed.
In this case, when the mobile terminal UE is located in the LTE macro cell, as shown in FIG. 9 (b), (1) the 3G macro cell is transmitted from the LTE macro cell by the CSFB function before making the special number transmission according to the menu operation. Move to the area. Thereafter, (2) special number transmission is performed in the state where the 3G macro cell is located, and guidance to the 3G femto cell is performed by the special number transmission. Thereby, the mobile terminal UE moves from the 3G macro cell to the 3G femto cell. In the example of FIG. 9B, a 3G femto cell and an LTE femto cell are formed by the femto radio base station HeNB. Therefore, in this case, the HomeLAC of the 3G macro cell and the HomeTAC of the LTE macro cell that cover the 3G femtocell located in the area are transmitted to the subscriber information server HSS via the exchange SGSN. Then, in the subscriber information server HSS, HomeLAC and HomeTAC of the 3G macro cell and the LTE macro cell covering the located 3G femto cell are stored.
In addition, although not shown in figure, there is also a method (existing function) by guidance according to the radio wave intensity as a third initial location method.

  Specifically, guidance to the femtocell is also performed when the radio field strength of the femtocell within the communicable range is greater than the radio field strength of the macrocell where the mobile terminal UE is located. Therefore, for example, if the location policy information is set to the C mode, when the location policy moves to the femtocell due to the radio field intensity, the location information is sent to the subscriber information server HSS via the exchange MME or the exchange SGSN. 3G macro cell HomeLAC and LTE macro cell HomeTAC that cover the femto cell. Then, in the subscriber information server HSS, HomeLAC and HomeTAC of 3G macro cell and LTE macro cell covering the located femto cell are stored.

(3) Regarding storage processing of location registration area information for C mode priority activation target Next, based on FIG. 10, information on the location registration area of the macro cell covering the LTE femtocell in the area serving as the priority activation target for C mode An example of the process of storing the will be described. FIG. 10 is a diagram illustrating an example of a process for storing information of a location registration area.
As shown in FIG. 10, the mobile terminal UE, for example, a macro cell #A belonging to the location registration area #A, a macro cell #B belonging to the location registration area #B, a macro cell #C belonging to the location registration area #C, Are moved in this order. As shown in FIG. 9, there is no LTE femto cell in the area of macro cell #A, and LTE femto cell FC # B and LTE femto cell FC # C exist in the areas of macro cell #B and #C, respectively. Further, it is assumed that the mobile terminal UE has never been in the LTE femtocell in the past, and the location policy information is set to the B mode.

  First, it is assumed that the mobile terminal UE is located in the macro cell #A as shown in (1) of FIG. Since the B mode is set as the location policy information, the LTE femtocell priority search is performed. However, since there is no LTE femto cell covered by the macro cell #A, the location registration area information (TAC or LAC) of the macro cell #A is not stored as a priority activation target in the C mode.

Next, as illustrated in (2) of FIG. 10, it is assumed that the mobile terminal UE has moved and is located in the macro cell #B. Here, the LTE femtocell priority search is performed, but since the position of (2) in FIG. 9 is outside the range of the LTE femtocell FC # B, the information on the location registration area of the macrocell #B is in the C mode. It is not stored as a priority activation target.
Next, as shown in (3) of FIG. 10, it is assumed that the mobile terminal UE moves within the macro cell #B and enters the range of the LTE femto cell FC #B. In this case, a priority search of the LTE femto cell is performed, and the mobile terminal UE is located in the LTE femto cell FC # B. Thereby, the information of the location registration area of the macro cell #B is stored as the priority activation target in the C mode.

  Next, as illustrated in (4) of FIG. 10, it is assumed that the mobile terminal UE has moved and is located in the macro cell #C. Here, the LTE femtocell priority search is performed, but since the position of (4) in FIG. 10 is outside the range of the LTE femtocell FC # C, the information on the location registration area of the macrocell #C is in the C mode. It is not stored as a priority activation target. Therefore, the information of the location registration area currently stored as the priority activation target is only for the macro cell #B.

Next, as illustrated in (5) of FIG. 10, it is assumed that the mobile terminal UE moves within the macro cell #C and enters the range of the LTE femto cell FC #C. In this case, a priority search of the LTE femto cell is performed, and the mobile terminal UE is located in the LTE femto cell FC # C. Thereby, the information of the location registration area of the macro cell #C is stored as the priority mode activation target of the C mode. Thereby, the information of the location registration area currently stored as the priority activation target is that of the macro cells #B and #C.
Thereafter, by changing the location policy information to the C mode, the mobile terminal UE is located in the macro cell #B or the macro cell #C belonging to the location registration area to be preferentially activated, so that the LTE femto cell is preferentially searched. Is done. On the other hand, in the macro cell #A that does not belong to the position registration area that is the priority activation target, the LTE femto cell priority search is not performed.

(4) Example of Operation of Mobile Communication System 1 Next, an example of the operation of the mobile communication system 1 of the present embodiment will be described based on FIGS.
Here, FIG. 11 is a sequence diagram showing an operation of the mobile communication system 1 according to the first operation example of the present embodiment. FIG. 12 is a flowchart illustrating an example of a processing procedure of SPID conversion processing. FIG. 13 is a sequence diagram showing an operation of the mobile communication system 1 according to the second operation example of the present embodiment.

  First, a first operation example of the mobile communication system 1 of the present embodiment will be described based on FIG. The first operation example is an operation when returning from the Preservation state in the LTE communication network. It is assumed that the exchange MME has already acquired the subscriber profile from the subscriber information server HSS in the prior Attach process.

As shown in FIG. 11, first, an RRC connection setting process is performed between the mobile terminal UE, the radio base station eNB, and the exchange MME (step S1000). After that, when the RRC connection is established, an “Initial UE Message” signal including Service Request and TAC information, which are S1-AP control signals, is transmitted from the radio base station eNB to the exchange MME (step S1002). . Thereby, the exchange MME acquires the TAC that is information on the location registration area of the LTE macro cell in which the mobile terminal UE is located. Next, an authentication process and a concealment process for the mobile terminal UE are executed between the mobile terminal UE, the radio base station eNB, and the exchange MME (step S1004). After that, when the mobile terminal UE is authenticated, SPID derivation processing is executed in the exchange MME (step S1006). Specifically, the exchange MME uses the IMEI acquired from the mobile terminal UE at the time of authentication processing in the terminal specification information acquisition unit 24 to obtain the terminal specification information of the mobile terminal UE specified by the IMEI from the subscriber information server HSS. get. Then, the priority frequency discrimination information setting unit 25 determines whether the mobile terminal UE has the CSFB function based on the acquired terminal specification information. If it is determined that the CSFB function is provided, “1” is acquired as the SPID value from the SPID management unit. On the other hand, if it is determined that the CSFB function is not provided, “2” is acquired as the SPID value from the SPID management unit.
When the SPID is derived in this way, the exchange MME next executes SPID conversion processing based on the location policy information included in the subscriber profile managed by the subscriber profile management unit 22 ( Step S1008).

Hereinafter, the operation of the SPID conversion process in the priority frequency discrimination information setting unit 25 of the exchange MME will be described with reference to FIG.
As shown in FIG. 12, when the SPID is derived, the priority frequency discrimination information setting unit 25 of the exchange MME first acquires the in-zone policy information via the subscriber profile management unit 22 (step S100). Next, the priority frequency discrimination information setting unit 25 of the exchange MME determines whether or not the A mode is set based on the located area policy information (step S102). If it is determined that the A mode is set (Yes in step S102), the derived SPID value is output to the transmitting unit 27 as it is (step S104). Thereafter, the series of processes is terminated and the process returns to the original process.

  On the other hand, if the priority frequency discrimination information setting unit 25 of the exchange MME determines that the B mode is set (No in S102) instead of the A mode (Yes in Step S106), the derived SPID is next. It is determined whether the value of “1” is “1” (step S108). Accordingly, when it is determined that the derived SPID value is “1” (Yes in step S108), the priority frequency discrimination information setting unit 25 of the exchange MME converts the SPID value “1” into “3”. (Step S110). Then, the converted SPID value “3” is output to the transmitter 27 (step S112). Thereafter, the series of processes is terminated and the process returns to the original process. If it is determined that the derived SPID value is “2” instead of “1” (No in step S108), the priority frequency discrimination information setting unit 25 of the exchange MME sets the SPID value “2” to “4”. (Step S114). Then, the converted SPID value “4” is output to the transmitter 27 (step S116).

  When the priority frequency discrimination information setting unit 25 of the exchange MME determines that the mode is not the B mode but the C mode (No in S106), it is included in the “Initial UE Message” signal received by the reception unit 20 next. TAC is acquired (step S118). The priority frequency discrimination information setting unit 25 of the exchange MME further acquires the HomeTAC included in the subscriber profile via the subscriber profile management unit 22 (step S120). Here, for example, it is assumed that four HomeTACs are acquired assuming that up to four HomeTACs are stored and held. The priority frequency discrimination information setting unit 25 of the exchange MME compares the acquired four HomeTACs with the acquired TACs (step S122). Then, the priority frequency discrimination information setting unit 25 of the exchange MME determines whether there is a HomeTAC that matches the acquired TAC (step S124). As a result, when it is determined that there is a matching HomeTAC (Yes in step S124), processing similar to that in the B mode is executed (steps S108 to S116). Thereafter, the series of processes is terminated and the process returns to the original process.

On the other hand, when the priority frequency discrimination information setting unit 25 of the exchange MME determines that there is no matching HomeTAC (No in step S124), the derived SPID value is directly transmitted to the transmission unit 27 as in the A mode. Output (step S104). Thereafter, the series of processes is terminated and the process returns to the original process.
Returning to FIG. 11, when the SPID conversion process is completed, the exchange MME transmits the SPID of the converted SPID to the SPID data field of the “Initial Context Setup Request” signal, which is the control signal of S1-AP, in the transmitter 27. Set the value. Then, an “Initial Context Setup Request” signal after setting the SPID is transmitted to the radio base station eNB (step S1010).

Thereafter, existing processes are continuously executed among the mobile terminal UE, the radio base station eNB, and the exchange MME (step S1012).
At this time, when receiving the “Initial Context Setup Request” signal from the exchange MME, the radio base station eNB acquires the SPID included in the received “Initial Context Setup Request” signal in the frequency determination unit 31. The frequency determination unit 31 determines a priority frequency band based on the acquired SPID value, and acquires priority frequency band information and priority information corresponding to the determined priority frequency band via the search frequency management unit 32. The frequency determination unit 31 outputs the acquired priority frequency band information and priority information to the transmission unit 33.

Thereafter, the transmission unit 33 transmits an “RRC Connection Release” signal including the priority frequency band information acquired from the frequency determination unit 31 to the mobile terminal UE at a timing of releasing the RRC connection (Step S1014).
Accordingly, when the mobile terminal UE acquires the frequency band information corresponding to the SPID value “1”, the mobile terminal UE searches for the 3G cell with priority. In addition, when the mobile terminal UE acquires frequency band information corresponding to the SPID value “2”, the mobile terminal UE searches for the LTE cell with priority. Also, when the mobile terminal UE acquires the frequency band information corresponding to the SPID value “3”, the mobile terminal UE searches the LTE femto cell with the highest priority, and if no LTE femto cell is found, then the 3G When a 3G cell is not found after searching for a cell of the scheme, the LTE macro cell is finally searched. Also, when the mobile terminal UE acquires the frequency band information corresponding to the SPID value “4”, the mobile terminal UE searches the LTE femto cell with the highest priority, and when the LTE femto cell is not found, When a macro cell is searched and an LTE macro cell is not found, a 3G cell is finally searched.

Next, a second operation example of the mobile communication system 1 of the present embodiment will be described based on FIG. The second operation example is an operation at the time of executing the RAU process in the 3G communication network. The example of FIG. 13 is an operation example when moving from a LTE macro cell or a 3G macro cell to another 3G macro cell having a different location registration area.
As shown in FIG. 13, first, an RRC connection setting process is performed between the mobile terminal UE and the radio network controller IPRNC (step S2000). After that, when the RRC connection is established, an "Initial UE Message" signal including RAU Request and LAC information, which is a control signal of the RANAP protocol, is transmitted from the radio network controller IPRNC to the new exchange SGSG which is a new exchange after moving in the area. Is transmitted (step S2002).

  When the exchange new SGSN receives the “Initial UE Message” signal, if the macro cell that has been in the area before moving to the 3G macro cell is a 3G macro cell, the exchange new SGSN is notified to the exchange old SGSN that is the exchange corresponding to the 3G macro cell. An “Identification Request” signal, which is a signal for acquiring information such as a subscriber profile corresponding to the mobile terminal UE that has moved within the range, is transmitted (step S2004).

On the other hand, when the exchange newSGSN receives the "Initial UE Message" signal, if the macro cell that was in the area before moving to the LTE area is an LTE macro cell, the exchange new SGSN sends an exchange to the exchange oldMME that is an exchange corresponding to the LTE macro cell. Then, a “Context Request” signal that is a signal for acquiring information such as a subscriber profile corresponding to the mobile terminal UE that has moved in the area is transmitted (step S2004).
When receiving the “Identification Request” signal, the exchange old SGSN transmits an ““ Identification Response ”signal including information such as a subscriber profile to the exchange new SGSN (step S2006).

On the other hand, when receiving the “Context Request” signal, the exchange oldMME transmits a “Context Response” signal including information such as a subscriber profile to the exchange newSGSN (step S2006).
Thereby, the exchange newSGSN acquires the subscriber profile including the in-zone policy information and the HomeLAC (up to four) from the exchange oldSGSN or the exchange oldMME.

  Thereafter, an authentication process for the mobile terminal UE is executed among the mobile terminal UE, the radio network controller IPRNC, the exchange newSGSN, and the exchange oldSGSN or the exchange oldMME (step S2008). Then, when the mobile terminal UE is authenticated, SPID deriving processing is executed in the exchange new SGSN (step S2010). Specifically, the exchange new SGSN uses the IMEI acquired from the mobile terminal UE at the time of authentication processing in the terminal specification information acquisition unit 24 to obtain the terminal specification information of the mobile terminal UE specified by the IMEI from the subscriber information server HSS. get. Then, the priority frequency discrimination information setting unit 25 determines whether the mobile terminal UE has the CSFB function based on the acquired terminal specification information. If it is determined that the CSFB function is provided, “1” is acquired as the SPID value from the SPID management unit. On the other hand, if it is determined that the CSFB function is not provided, “2” is acquired as the SPID value from the SPID management unit.

When the SPID is derived in this way, the exchange new SGSN next executes SPID conversion processing based on the location policy information included in the subscriber profile managed by the subscriber profile management unit 22 ( Step S2012).
Note that the SPID conversion process is performed by the priority frequency discrimination information setting unit 25 of the exchange new SGSN in the process of step S1008 in the first operation example, the LAC in which the mobile terminal UE is located, the subscriber The other processes are the same except that the HomeLAC included in the profile is compared. Therefore, the description is omitted.

  Returning to FIG. 13, when the SPID conversion process is completed, the exchange new SGSN sets the SPID value after the conversion process in the SPID data field of the “Common ID” signal that is the control signal of the RANAP protocol in the transmission unit 27. To do. Then, a “Common ID” signal after setting the SPID is transmitted to the radio network controller IPRNC (step S2014).

Thereafter, a concealment process for the mobile terminal UE is performed among the mobile terminal UE, the radio network controller IPRNC, the exchange newSGSN, and the exchange oldSGSN or the exchange oldMME (step S2016).
Thereafter, existing processes are continuously executed among the mobile terminal UE, the radio network controller IPRNC, the exchange new SGSN, and the exchange old SGSN or the exchange oldMME (step S2018).

  At this time, when receiving the “Common ID” signal from the exchange new SGSN, the radio network controller IPRNC acquires the SPID included in the received “Common ID” signal in the frequency discrimination unit 31. The frequency determination unit 31 determines a priority frequency band based on the acquired SPID value, and acquires priority frequency band information and priority information corresponding to the determined priority frequency band via the search frequency management unit 32. The frequency determination unit 31 outputs the acquired priority frequency band information and priority information to the transmission unit 33.

Thereafter, the transmission unit 33 transmits, to the mobile terminal UE, an “RRC Connection Release” signal including the priority frequency band information and priority information acquired from the frequency determination unit 31 at the timing of releasing the RRC connection (Step S2020).
Note that the cell search process in the mobile terminal UE is the same as that in the first operation example, and a description thereof will be omitted.

(5) Operation and effect In the mobile communication system 1 according to the above embodiment, in the subscriber information server HSS, the in-zone policy information set by the user using the customer control function and the femtocell in the past It is possible to store and hold a subscriber profile including information on a location registration area of a macro cell (cover cell) that covers Here, the subscriber information server HSS stores information on the location registration area of the cover cell by a preset upper limit number.

  Furthermore, the subscriber profile can be obtained from the subscriber information server HSS in the exchange MME and the exchange SGSN. Furthermore, in the exchange MME and the exchange SGSN, it is possible to obtain the specification information of the mobile terminal UE specified by IMEI from the subscriber information server HSS using the IMEI obtained from the mobile terminal UE. Furthermore, the SPID can be derived based on the acquired specification information in the exchange MME and the exchange SGSN. Further, in the exchange MME or the exchange SGSN, conversion processing of the derived SPID is executed based on the derived SPID, the location policy information acquired from the subscriber information server HSS, and the information on the location registration area of the cover cell. It is possible.

  Specifically, the SPID conversion process does not convert the derived SPID value when the A mode is set as the in-zone policy information. When the B mode is set as the in-zone policy information, the derived SPID value is converted to a numerical value that causes the LTE femto cell to be searched with the highest priority. Further, when the C mode is set as the in-zone policy information, the location registration area information of the macro cell where the mobile terminal UE is currently located and the previously stored femto cell in the past are covered. The information in the location registration area of the macro cell is compared. Then, the SPID value derived only when there is a match between both is converted into a numerical value that causes the LTE femto cell to be searched with the highest priority.

  Further, the exchange MME sets the SPID value after the conversion process in the SPID field on the standard control signal of the S1-AP standard control signal which is a standard communication protocol with the radio base station eNB. It is possible to transmit a later control signal to the radio base station eNB. Specifically, it is possible to set the SPID value after the conversion process in the SPID field of the “Initial Context Setup Request” signal and transmit the set signal to the radio base station eNB.

  On the other hand, the exchange SGSN sets the SPID value after conversion processing in the standard SPID field of the standard control signal of the RANAP protocol which is a standard communication protocol with the radio network controller IPRNC. Can be transmitted to the radio network controller IPRNC. Specifically, the SPID value after the conversion process can be set in the SPID field of the “Common ID” signal, and the set signal can be transmitted to the radio network controller IPRNC.

Furthermore, when the radio base station eNB and the radio network controller IPRNC receive the control signal including the converted SPID value, the search including the priority frequency band information according to the SPID value is performed based on the SPID included in the received signal. It is possible to transmit a frequency designation signal to the mobile terminal UE.
The radio base station eNB and the radio network controller IPRNC can transmit a search frequency designation signal to the mobile terminal UE at a timing when the mobile terminal UE transitions to the idle state.

As described above, the exchange can set the control signal including the SPID corresponding to the in-zone policy information in the standard SPID dedicated field of the standard signal of the standard protocol and transmit it to the wireless control device. Thereby, the effect that the mobile communication system with comparatively high versatility can be constructed is obtained.
Moreover, since the femtocell can be preferentially searched regardless of the location history by setting the B mode, the frequency with which the mobile terminal UE is located in the femtocell can be increased. Thereby, the effect that the effect of traffic off-load can be improved is acquired.

Also, by setting the C mode, it is possible to preferentially search for femtocells when they are located in a macrocell in an area that matches the location registration area of the macrocell that covers the previously stored femtocell It becomes. Thereby, compared with the case of B mode, the frequency which exists in the femtocell can be made higher than before, suppressing the power consumption of the mobile terminal UE. Therefore, it is possible to improve the traffic offload effect while suppressing battery consumption.
In addition, since the search frequency designation signal corresponding to the SPID can be transmitted at the timing when the mobile terminal UE transitions to the idle state, it is possible to prevent the occurrence of a problem that the packet communication is forcibly disconnected. The effect that it can be obtained.

(6) Modification (6-1) In the above embodiment, when the B mode and the C mode are set, information on the location registration area of the macro cell covering the existing femto cell is preset in the subscriber information server HSS. However, the present invention is not limited to this configuration.
For example, the information on the location registration area of the cover cell may be stored in the subscriber information server HSS only when the C mode is set. In this case, it is desirable to display information indicating that the mobile terminal UE is located in the femto cell by a “GMM information” signal or the like. With this configuration, the user can store the information on the coverage area of the desired femtocell in the subscriber information server HSS by changing to the C mode after staying in the desired femtocell in the B mode. it can. That is, the priority search can be activated only for a desired femtocell.

(6-2) In the above embodiment, in the LTE communication network, the “Initial Context Setup Request” signal is used to transmit the converted SPID to the radio base station eNB. Not limited to. The SPID subjected to the conversion process may be transmitted to the radio base station eNB using another control signal having a standard field dedicated to SPID.

The above embodiments are preferable specific examples of the present invention, and various technically preferable limitations are given. However, the scope of the present invention is described in particular in the above description to limit the present invention. As long as there is no, it is not restricted to these forms. In the drawings used in the above description, for convenience of illustration, the vertical and horizontal scales of members or parts are schematic views different from actual ones.
In addition, the present invention is not limited to the above-described embodiments, and modifications, improvements, equivalents, and the like within the scope that can achieve the object of the present invention are included in the present invention.

(7) Correspondence with the Present Invention In the embodiment described above, the subscriber profile acquisition unit 21 corresponds to the in-zone policy information acquisition unit, and the priority frequency discrimination information setting unit 25 corresponds to the discrimination information setting unit. The transmission unit 27 corresponds to a priority frequency determination signal transmission unit.
Moreover, in the said embodiment, the memory | storage process of the location registration area information of a cover cell via exchange MME and exchange SGSN respond | corresponds to a 1st large cell identification information registration part, and the in-zone macrocell information acquisition part 23 is 1st. Corresponding to the large cell identification information acquisition unit, the reception unit 20 corresponds to the control signal reception unit.
In the above embodiment, the receiving unit 30 corresponds to the priority frequency discrimination signal receiving unit, the priority frequency discrimination unit 31 corresponds to the frequency band discrimination unit, and the transmission unit 33 corresponds to the search frequency designation signal transmission unit. To do.

DESCRIPTION OF SYMBOLS 1 Mobile communication system HSS Subscriber information server MME, SGSN exchange IPRNC radio control apparatus eNB radio base station HeNB femto radio base station UE Mobile terminal 20, 30, 40 Receiving part 21 Subscriber profile acquisition part 23 Location macro cell information acquisition part 24 Terminal specification information acquisition unit 25 Priority frequency discrimination information setting unit 27, 33, 45 Transmission unit 31 Priority frequency discrimination unit 41 Cell search unit 43 Special number transmission unit 44 Location policy setting unit

Claims (10)

A large cell that is configured to include a plurality of mobile communication networks respectively corresponding to a plurality of types of mobile communication systems and that has a relatively large area capable of communicating with a mobile terminal, and the communicable area In a mobile communication system configured to include a small cell that is a cell that is smaller than the large cell, and wireless communication with the mobile terminal via the large cell and the small cell An exchange having a radio control device for controlling radio communication with the mobile terminal.
Location policy information, which is information for setting whether to preferentially reside in the small cell of the mobile terminal set in advance, is acquired from a subscriber information holding device provided in the mobile communication system. Area policy information acquisition unit,
Priority frequency discrimination information that is information for discriminating a frequency band of a cell corresponding to a communication method that the mobile terminal should prevail in, and the location policy information acquired by the location policy information acquisition unit, A discrimination information setting unit for setting priority frequency discrimination information including discrimination information capable of discriminating a frequency band of a cell to be preferentially located based on
An exchange comprising: a priority frequency discrimination signal transmission unit that transmits a priority frequency discrimination signal, which is a control signal including the priority frequency discrimination information set by the discrimination information setting unit, to the radio control device. The location policy information includes small cell priority location policy information that preferentially exists the mobile terminal to all the small cells,
If the determination information setting unit determines that the area policy information is the small cell priority area policy information, it determines that the frequency band of the cell to be preferentially located is the frequency band of the small cell. 2. The exchange according to claim 1, wherein priority frequency discrimination information including possible discrimination information is set. The location policy information includes specific small cell priority location policy information that preferentially exists the mobile terminal from the specific large cell to the small cell existing in the large cell,
Based on a control signal related to location registration that occurs in response to the mobile terminal being in the small cell, the identification information of the large cell including the area of the small cell in which the mobile terminal is located A first large cell identification information registration unit for registering certain first large cell identification information in the subscriber information holding device;
A first large cell identification information acquisition unit for acquiring the first large cell identification information from the subscriber information holding device;
A control signal receiving unit that receives a control signal including second large cell identification information that is identification information of the large cell in which the mobile terminal is located from the radio control device;
The discrimination information setting unit determines the content of the location policy information in response to receiving the control signal by the control signal reception unit, and the location policy information is the specific small cell priority location policy information. If it is determined that there is, the first large cell identification information acquired by the first large cell identification information acquisition unit is compared with the second large cell identification information included in the control signal received by the control signal reception unit. If it is determined that the first large cell identification information and the second large cell identification information match, it is possible to determine that the frequency band of the cell to be preferentially located is the frequency band of the small cell When the priority frequency discrimination information including information is set and it is determined that the first large cell identification information and the second large cell identification information do not match, the frequency band of the cell to be preferentially located is the movement Based on device specifications Exchanger according to claim 1 or claim 2, characterized in that setting the priority frequency discrimination information including a discernable determination information that it is a frequency band of a preset communication method.   The discrimination information setting unit is set in advance when setting the priority frequency discrimination information including discrimination information capable of discriminating that the frequency band of the cell to be preferentially located is the frequency band of the small cell. The frequency band of the small cell corresponding to the communication method is given the highest priority, the frequency band to be preferentially located next is the frequency band of the cell of the communication method set in advance based on the specifications of the mobile terminal, The priority frequency discrimination including discriminating information capable of discriminating a plurality of frequency bands prioritized in a stepwise manner by setting a frequency band to be preferentially located after the frequency band as a frequency band of a cell of another communication method. The exchange according to claim 2 or 3, wherein information is set. The plurality of types of communication methods include a 3G (3rd Generation) method,
The priority frequency discrimination information is an SPID (Radio Access Network Application Part) protocol control signal, which is a communication protocol used in communication between the exchange and the radio network controller, in a 3G communication network. 5. The exchange according to any one of claims 1 to 4, wherein the exchange is a subscriber profile ID for radio frequency priority. The plurality of types of communication methods include an LTE (Long Term Evolution) method,
The priority frequency discrimination information is an SPID (Subscriber) included in a control signal of S1-AP (S1 Application Protocol) which is a communication protocol used in communication between the exchange and the radio control apparatus in an LTE communication network. 6. The exchange according to any one of claims 1 to 5, characterized in that the profile ID for Radio Frequency Priority). A large cell that is configured to include a plurality of mobile communication networks respectively corresponding to a plurality of types of mobile communication systems and that has a relatively large area capable of communicating with a mobile terminal, and the communicable area In a mobile communication system configured to include a small cell that is a cell that is smaller than the large cell, and wireless communication with the mobile terminal via the large cell and the small cell An exchange control program executed in a computer provided in an exchange having a radio control device under control of radio communication with the mobile terminal,
Location policy information, which is information for setting whether to preferentially reside in the small cell of the mobile terminal set in advance, is acquired from a subscriber information holding device provided in the mobile communication system. Zone policy information acquisition step,
Priority frequency determination information that is information for determining a frequency band of a cell corresponding to a communication method that the mobile terminal should be preferentially located in, and the area policy information acquired in the area policy information acquisition step A discrimination information setting step for setting priority frequency discrimination information including discrimination information capable of discriminating a frequency band of a cell to be preferentially located based on
A priority frequency discrimination signal transmission step for transmitting a priority frequency discrimination signal, which is a control signal including the priority frequency discrimination information set in the discrimination information setting step, to the radio network controller. An exchange control program characterized by that. A large cell that is configured to include a plurality of mobile communication networks respectively corresponding to a plurality of types of mobile communication systems, and that has a relatively large area for communication with a mobile terminal, and a larger cell than the large cell In a mobile communication system configured to include a small cell whose size of the communicable area is a very small cell, wireless communication with the mobile terminal via the large cell and via the small cell An exchange control method for controlling an exchange having a radio control device for controlling radio communication with the mobile terminal.
A subscriber information holding device provided in the mobile communication system with location policy information which is information for setting whether or not the exchange preferentially exists in the small cell of the mobile terminal set in advance The location policy information acquisition step acquired from
The switch receives priority frequency discrimination information that is information for discriminating a frequency band of a cell corresponding to a communication scheme that the mobile terminal should prevail in, and the presence policy information acquired in the location policy information acquisition step. A discrimination information setting step for setting priority frequency discrimination information including discrimination information capable of discriminating a frequency band of a cell to be preferentially located based on zone policy information;
The switch includes a priority frequency determination signal transmission step of transmitting a priority frequency determination signal, which is a control signal including the priority frequency determination information set in the determination information setting step, to the radio control apparatus. Switch control method. A large cell that is configured to include a plurality of mobile communication networks respectively corresponding to a plurality of types of mobile communication systems and that has a relatively large area capable of communicating with a mobile terminal, and the communicable area In a mobile communication system configured to include a small cell that is a cell that is smaller than the large cell, and wireless communication with the mobile terminal via the large cell and the small cell A wireless control device for controlling wireless communication with the mobile terminal,
Priority frequency discrimination information that is information for discriminating a frequency band of a cell corresponding to a communication scheme that the mobile terminal should prevail from an exchange having the radio control device under control, and the mobile terminal Priority frequency including discriminating information that can be used to determine the frequency band of the cell that should preferentially be set, based on the location policy information that sets whether to preferentially exist in the small cell A priority frequency discrimination signal receiving unit that receives a priority frequency discrimination signal that is a control signal including discrimination information;
Based on priority frequency discrimination information included in the priority frequency discrimination signal received from the exchange, a frequency band discrimination unit that discriminates a frequency band of a cell corresponding to a communication method that the mobile terminal should prevail in, and
A search frequency designation signal transmission unit for transmitting a search frequency designation signal, which is a control signal including information for designating the frequency band determined by the frequency band discrimination unit as a search frequency band of the cell of the mobile terminal, to the mobile terminal; With
The radio frequency control apparatus, wherein the search frequency designation signal transmission unit transmits the search frequency designation signal to the mobile terminal at a timing when the mobile terminal transitions to a standby state. A large cell that is configured to include a plurality of mobile communication networks respectively corresponding to a plurality of types of mobile communication systems and that has a relatively large area capable of communicating with a mobile terminal, and the communicable area A mobile communication system including a small cell whose size is a cell smaller than the large cell,
A radio controller for controlling radio communication with the mobile terminal via the large cell and radio communication with the mobile terminal via the small cell, an exchange subordinate to the radio controller, and a subscription Subscriber information holding device for holding subscriber information,
The subscriber information holding device is:
Resident policy that transmits to the switch, the visited policy information, which is information for setting whether or not the small cell of the mobile terminal is preferentially set in response to an acquisition request from the switch With an information transmitter
The exchange is
A location policy information acquisition unit that acquires the location policy information from the subscriber information holding device;
Priority frequency discrimination information that is information for discriminating a frequency band of a cell corresponding to a communication method that the mobile terminal should prevail in, and the location policy information acquired by the location policy information acquisition unit, A discrimination information setting unit for setting priority frequency discrimination information including discrimination information capable of discriminating a frequency band to be preferentially located based on
A priority frequency discrimination signal transmission unit that transmits a priority frequency discrimination signal, which is a control signal including the priority frequency discrimination information set by the discrimination information setting unit, to the radio control device;
The wireless control device
A priority frequency discrimination signal receiving unit for receiving the priority frequency discrimination signal from the exchange;
A frequency band for discriminating a frequency band of a cell corresponding to a communication method to be preferentially located by the mobile terminal based on priority frequency discrimination information included in the priority frequency discrimination signal received by the priority frequency discrimination signal receiving unit A discriminator;
A search frequency designation signal transmission unit for transmitting a search frequency designation signal, which is a control signal including information for designating the frequency band determined by the frequency band discrimination unit as a search frequency band of the cell of the mobile terminal, to the mobile terminal; A mobile communication system comprising:

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