JP2018029273A - Radio base station and communication device - Google Patents

Abstract

[PROBLEMS] To reduce the possibility that Full Configuration is performed in handover.
A radio base station eNB1 capable of radio communication with a terminal device UE, and when the terminal device UE is handed over from the radio base station eNB2 to the radio base station eNB1, the radio base station eNB2 has the radio base station eNB1 Determining whether or not to have a function different from the function, and deletion of setting information related to radio communication with the radio base station eNB2 for the terminal device UE when the result of the determination by the determination unit 12 is affirmative A radio base station eNB1, comprising: an instruction unit 13 for instructing
[Selection] Figure 10

Description

  The present invention relates to a radio base station and a communication device.

  In recent years, introduction and deployment of wireless communication systems compliant with LTE (Long Term Evolution) standards have been promoted. The LTE standard is sequentially revised and released by 3GPP (Third Generation Partnership Project). For this reason, radio base stations eNB with different releases are mixed in a plurality of radio base stations eNB (evolved Node B) provided in a radio communication system compliant with the LTE standard. Therefore, in order for the terminal device UE (User Equipment) to communicate with the radio base station eNB, setting information (configuration) related to communication with the radio base station eNB set in the terminal device UE is set to the radio base station eNB. The content needs to conform to the release (an example of “type of radio base station”).

  By the way, when the terminal device UE performs handover between the radio base stations eNB, the configuration set in the terminal device UE for communication with the source radio base station S-eNB that is the handover source, and the target radio base that is the handover destination The difference information (hereinafter may be simply referred to as “difference information”) between the configuration to be set in the terminal apparatus UE for communication with the station T-eNB is transmitted from the target radio base station T-eNB to the terminal apparatus UE. “Delta Configuration”, which is a process of notifying to (see Non-Patent Document 1), is defined.

  FIG. 1 is an explanatory diagram for explaining handover with Delta Configuration. In FIG. 1, as an example, it is assumed that the source radio base station S-eNB conforms to Release 11 (Rel-11) and the target radio base station T-eNB conforms to Release 12 (Rel-12). ing.

  When the source radio base station S-eNB starts handover with Delta Configuration, as shown in (A1) of FIG. 1, the source radio base station S-eNB performs handover to the target radio base station T-eNB by X2AP (X2 Application Protocol). A Handover Request (HO request) including Preparation Information (HO Prep Info) is transmitted. The HO Prep Info includes information indicating a configuration related to communication between the terminal apparatus UE and the source radio base station S-eNB.

When receiving the HO request, the target radio base station T-eNB, based on the HO Prep Info included in the received HO request, the configuration related to the communication between the terminal device UE and the source radio base station S-eNB, and the terminal device UE Difference information required for starting communication with the target radio base station T-eNB, and a handover command (HO command) including the difference information is generated.
Then, the target radio base station T-eNB transmits a Handover Request Ack (HO request Ack) including the HO command to the source radio base station S-eNB by X2AP as shown in (A2) of FIG. To do.

The source radio base station S-eNB transfers the HO command transmitted from the target radio base station T-eNB to the terminal apparatus UE, as shown in (A3) of FIG.
When the terminal apparatus UE receives the HO command from the source radio base station S-eNB, as illustrated in (A4) of FIG. 1, the terminal apparatus UE and the target radio base station T-eNB are based on the difference information included in the HO command. The configuration for performing the communication is set. Thereby, as shown to (A5) of FIG. 1, the terminal device UE releases the bearer established between source radio base station S-eNB, and communicates with target radio base station T-eNB. Start.

  Thus, according to the handover with Delta Configuration, the target radio base station T-eNB notifies the terminal apparatus UE of the difference information, and thus the target radio base station T-eNB notifies the terminal apparatus UE of the target radio. The data size of the HO command can be reduced as compared with the case where all configurations related to communication with the base station T-eNB are notified.

By the way, the configuration included in the HO Prep Info transmitted from the source radio base station S-eNB may include an information element that cannot be understood by the target radio base station T-eNB. For example, when the configuration included in the HO Prep Info includes an information element that conforms to a release newer than the release that the target radio base station T-eNB complies with, the target radio base station T-eNB cannot understand the information element. Probability is high.
However, in the handover with Delta Configuration, even if the configuration included in HO Prep Info includes an information element that cannot be understood by the target radio base station T-eNB, the difference information is not taken into account. Is generated. Therefore, in the handover with Delta Configuration, communication between the terminal apparatus UE and the target radio base station T-eNB is performed in a state where information elements that are not understood by the target radio base station T-eNB are set in the terminal apparatus UE. Since it may be started, a problem may occur in the communication.

  For this reason, in 3GPP, when the terminal device UE is handed over from the source radio base station S-eNB to the target radio base station T-eNB, in the terminal device UE, the terminal device UE and the source radio base station S-eNB “Full Configuration”, which is a process for deleting a configuration related to communication, is defined (see Non-Patent Document 1).

  FIG. 2 is an explanatory diagram for explaining handover with full configuration. In FIG. 2, as an example, it is assumed that the source radio base station S-eNB conforms to Release 12 (Rel-12) and the target radio base station T-eNB conforms to Release 11 (Rel-11). ing.

  When the source radio base station S-eNB starts handover with Full Configuration, as shown in (B1) of FIG. 2, the source radio base station S-eNB sends HO Prep Info having ue-ConfigRelease to the target radio base station T-eNB. Send a HO request containing. Here, ue-ConfigRelease is information (an example of “type information”) indicating a release that the function of the source radio base station S-eNB complies with. In other words, ue-ConfigRelease is information indicating a release that conforms to the configuration set in the terminal apparatus UE for communication with the source radio base station S-eNB.

When the target radio base station T-eNB receives the HO request, as shown in (B2) of FIG. 2, the target radio base station T-eNB determines whether or not full configuration needs to be performed based on the ue-ConfigRelease included in the HO request. To do.
Specifically, the target radio base station T-eNB determines whether or not the release indicated by the ue-ConfigRelease received from the source radio base station S-eNB is newer than the release to which the target radio base station T-eNB complies. to decide. Then, when the release indicated by ue-ConfigRelease is newer than the release that the target radio base station T-eNB complies with, the target radio base station T-eNB determines that the Full Configuration needs to be performed.

  Next, the target radio base station T-eNB transmits a HO request Ack including the HO command to the source radio base station S-eNB, as shown in (B3) of FIG. In addition, the target radio base station T-eNB includes a configuration to be set in the terminal device UE for communication with the target radio base station T-eNB with respect to the HO command when performing handover with Full Configuration. Make it. In addition, when the target radio base station T-eNB executes a handover with the full configuration, the target radio base station T-eNB includes fullConfig-r9 (information instructing execution of the full configuration) in the HO command.

As illustrated in (B4) of FIG. 2, the source radio base station S-eNB transfers the HO command transmitted from the target radio base station T-eNB to the terminal device UE.
When receiving the HO command including fullConfig-r9 (information instructing implementation of Full Configuration) as shown in (B5) of FIG. 2, the terminal apparatus UE receives a C-RNTI (Cell-Radio Network Temporary Identifier) and security. The configuration related to the communication with the source radio base station S-eNB excluding the information related to is deleted, and the bearer established with the source radio base station S-eNB is released. And the terminal device UE sets configuration regarding communication with the target radio base station T-eNB based on the received HO command. Thereby, as shown to (B6) of FIG. 2, the terminal device UE starts communication with the target radio base station T-eNB.

3GPP TS36.331

  As described above, in handover with Full Configuration, Delta Configuration is used to transmit all configurations related to communication with the target radio base station T-eNB from the target radio base station T-eNB to the terminal device UE. Compared with a handover involving a HO command, the data size of the HO command increases, and there is a high possibility that radio resources will be constrained. Further, in handover with Full Configuration, user data transmitted from the terminal apparatus UE to the source radio base station S-eNB cannot be transferred to the target radio base station T-eNB, so compared with handover with Delta Configuration. Thus, there is a high possibility that the user data needs to be retransmitted to the target radio base station T-eNB.

  The present invention has been made in view of the above-described circumstances, and an object of the present invention is to provide a technique that can reduce the possibility that Full Configuration is performed in handover.

  In order to solve the above problems, a radio base station according to the present invention is a radio base station capable of radio communication with a terminal device, and when the terminal device is handed over from another radio base station to the radio base station. A determination unit that determines whether or not the other radio base station has a function different from the function of the radio base station, and if the result of the determination is affirmative, An instruction unit for instructing deletion of setting information related to wireless communication with the wireless base station.

  According to the present invention, it is possible to reduce the possibility that Full Configuration is performed in handover.

It is explanatory drawing for demonstrating the handover accompanying Delta Configuration. It is explanatory drawing for demonstrating the handover accompanying Full Configuration. It is explanatory drawing which shows an example of the radio | wireless communications system SYS which concerns on 1st Embodiment of this invention. It is a functional block diagram which shows an example of a structure of radio base station eNB1. It is a functional block diagram which shows an example of a structure of radio base station eNB2. It is a block diagram which shows an example of the hardware constitutions of radio base station eNB1. It is a block diagram which shows an example of the hardware constitutions of radio base station eNB2. It is a block diagram which shows an example of the hardware constitutions of the terminal device UE. 10 is a sequence chart showing an example of operation of the wireless communication system SYS. It is a flowchart which shows an example of operation | movement of the radio base station eNB1 in a full configuration implementation determination process. It is explanatory drawing for demonstrating a function presence determination process. It is explanatory drawing for demonstrating a function presence determination process. It is a functional block diagram which shows an example of a structure of radio base station eNB1-A which concerns on 2nd Embodiment. It is a flowchart which shows an example of operation | movement of radio base station eNB1-A in a full configuration implementation determination process. It is explanatory drawing for demonstrating the base station function information Dat which concerns on the modification 1. FIG. It is explanatory drawing for demonstrating the function presence determination process which concerns on the modification 1. FIG.

<< A. First embodiment >>
Embodiments according to the present invention will be described below with reference to the drawings. In the drawings, the dimensions and scales of each part are appropriately different from actual ones. Further, since the embodiments described below are preferable specific examples of the present invention, various technically preferable limitations are attached thereto. However, the scope of the present invention is particularly limited in the following description. Unless otherwise stated, the present invention is not limited to these forms.

<< 1. Configuration of wireless communication system >>
Hereinafter, an outline of the wireless communication system SYS according to the present embodiment will be described.

  FIG. 3 is an explanatory diagram showing an example of the wireless communication system SYS according to the present embodiment.

  As shown in FIG. 3, the radio communication system SYS is a radio communication system compliant with the LTE standard, and includes a plurality of radios including a terminal device UE such as a mobile phone or a smartphone, a radio base station eNB1, and a radio base station eNB2. A base station eNB, and an upper node ND such as an S-GW (Serving Gateway) and an MME (Mobility Management Entity). In the present embodiment, it is assumed that the terminal apparatus UE is handed over from the radio base station eNB2 to the radio base station eNB1. That is, in the present embodiment, it is assumed that the radio base station eNB1 operates as a target radio base station and the radio base station eNB2 operates as a source radio base station. In the present embodiment, it is assumed that the radio base station eNB1 conforms to Release 11 (Rel-11) and the radio base station eNB2 conforms to Release 12 (Rel-12).

FIG. 4 is a functional block diagram showing an example of the configuration of the radio base station eNB1 according to the present embodiment.
As illustrated in FIG. 4, the radio base station eNB1 performs radio communication for performing radio communication with the control unit 10 that controls the entire radio base station eNB1, a storage unit 110 that stores various types of information, and the terminal device UE. Unit 120 and a wired communication unit 130 for communicating with the radio base station eNB2 and the upper node ND.

  The storage unit 110 stores various types of information including the control program PRG1 of the radio base station eNB1 and base station function information Dat1 representing the function of the radio base station eNB1.

The control unit 10 includes an information acquisition unit 11, a determination unit 12, and an instruction unit 13.
Among these, the information acquisition unit 11 acquires information transmitted from the radio base station eNB2. In addition, when the terminal unit UE is handed over from the radio base station eNB2 to the radio base station eNB1, the determination unit 12 does not have the radio base station eNB1 among the functions possessed by the radio base station eNB2. A function presence / absence determination process, which is a process for determining whether or not a function exists, is executed. Further, the instruction unit 13 instructs the terminal device UE to perform Full Configuration based on the determination result in the determination unit 12 when the terminal device UE is handed over from the radio base station eNB2 to the radio base station eNB1. .

FIG. 5 is a functional block diagram showing an example of the configuration of the radio base station eNB2 according to the present embodiment.
As illustrated in FIG. 5, the radio base station eNB2 performs radio communication for performing radio communication with the control unit 20 that controls the entire radio base station eNB2, a storage unit 210 that stores various types of information, and the terminal device UE. Unit 220 and a wired communication unit 230 for communicating with the radio base station eNB1 and the upper node ND.

The storage unit 210 stores various types of information including the control program PRG2 of the radio base station eNB2 and base station function information Dat2 representing the function of the radio base station eNB2. Hereinafter, the base station function information Dat1 and Dat2 are collectively referred to as base station function information Dat. That is, in the present embodiment, each radio base station eNB provided in the radio communication system SYS has base station function information Dat representing a function of the radio base station eNB in a storage unit provided in the radio base station eNB. Is remembered.
The control unit 20 includes a handover processing unit 21 that performs various processes for handing over the terminal device UE from the radio base station eNB2 to the radio base station eNB1.

In this embodiment, the case where the radio base station eNB1 operates as a target radio base station and the radio base station eNB2 operates as a source radio base station will be described as an example. However, the radio base station eNB1 The radio base station eNB2 may be operable as a target radio base station. That is, the control unit 10 may include a handover processing unit 21, and the control unit 20 may include an information acquisition unit 11, a determination unit 12, and an instruction unit 13.
In the present embodiment, the case where the communication between the radio base stations eNB and the communication between the radio base station eNB and the upper node ND is wired communication is exemplified, but the present invention is limited to such an aspect. The communication between the radio base stations eNB and the communication between the radio base station eNB and the upper node ND may be radio communication.
Each function (component) shown in FIGS. 4 and 5 may be realized by hardware, software, or a combination of hardware and software. Each of the functions shown in FIGS. 4 and 5 may be realized by one device physically or logically coupled, or two or more devices separated physically or logically may be directly or indirectly. For example, it may be realized by the two or more devices connected by wire or wireless.

  FIG. 6 is a configuration diagram illustrating an example of a hardware configuration of the radio base station eNB1 according to the present embodiment.

As illustrated in FIG. 6, the radio base station eNB1 includes a processor 1000 that controls the entire radio base station eNB1, a memory 1001 and a storage 1002 that store various types of information, and an input device 1003 that receives input of various types of information. , An output device 1004 for outputting various information, a communication device 1005 for performing communication with the outside of the radio base station eNB1, and a bus 1006 for transmitting information inside the radio base station eNB1.
The memory 1001 is, for example, a volatile memory such as a RAM (Random Access Memory) that functions as a work area of the processor 1000, and an EEPROM (Electrically Erasable Programmable Read-Only) that stores various information such as the control program PRG1 of the radio base station eNB1. And a non-volatile memory such as a memory, and provides a function as the storage unit 110.
The processor 1000 is, for example, a CPU (Central Processing Unit), executes the control program PRG1 stored in the memory 1001, and operates according to the control program PRG1, thereby obtaining the information acquisition unit 11, the determination unit 12, and the instruction unit 13. It functions as the control part 10 containing these.
The communication device 1005 is hardware for performing communication with the radio base station eNB2 and the terminal device UE via one or both of the wired network and the wireless network, and functions as the wireless communication unit 120 and the wired communication unit 130. provide.

  FIG. 7 is a configuration diagram illustrating an example of a hardware configuration of the radio base station eNB2 according to the present embodiment.

As illustrated in FIG. 7, the radio base station eNB2 includes a processor 2000 such as a CPU that controls the entire radio base station eNB2, a memory 2001 and a storage 2002 that store various information, and an input for receiving input of various information. A device 2003, an output device 2004 for outputting various information, a communication device 2005 for performing communication with the outside of the radio base station eNB2, a bus 2006 for transmitting information inside the radio base station eNB2, Is provided.
The memory 2001 includes, for example, a volatile memory such as a RAM that functions as a work area of the processor 2000, and a nonvolatile memory such as an EEPROM that stores various information such as the control program PRG2 of the radio base station eNB2. As a function.
The processor 2000 is a CPU, for example, and functions as the control unit 20 including the handover processing unit 21 by executing the control program PRG2 stored in the memory 2001 and operating according to the control program PRG2.
The communication device 2005 is hardware for performing communication with the radio base station eNB1 and the terminal device UE via one or both of the wired network and the wireless network, and functions as the wireless communication unit 220 and the wired communication unit 230. provide.

  FIG. 8 is a configuration diagram illustrating an example of a hardware configuration of the terminal device UE according to the present embodiment.

  As illustrated in FIG. 8, the terminal device UE includes a processor 3000 such as a CPU that controls the entire terminal device UE, a memory 3001 and a storage 3002 that store various information, and an input device 3003 that receives input of various information. And an output device 3004 for outputting various information, a communication device 3005 for communicating with the outside of the terminal device UE, and a bus 3006 for transmitting information inside the terminal device UE.

<< 2. Operation of wireless communication system >>
Hereinafter, the operation of the wireless communication system SYS will be described with reference to FIGS.

<< 2.1. About handover >>
FIG. 9 is a sequence chart showing an example of the operation of the radio communication system SYS when the terminal apparatus UE is handed over from the radio base station eNB2 to the radio base station eNB1.

As illustrated in FIG. 9, before the handover is performed, the terminal apparatus UE transmits user data (Packet Data) to the upper node ND via a bearer established between the terminal apparatus UE and the radio base station eNB2. Or user data is received from the upper node ND (S10).
Further, the terminal device UE periodically measures the reception quality of the radio wave received from the radio base station eNB1, for example, the received power of the radio wave, and includes information indicating the measurement result for the radio base station eNB2. Measurement Report is transmitted (S11).

  As illustrated in FIG. 9, the handover processing unit 21 of the radio base station eNB2 determines whether or not to hand over the terminal device UE to the radio base station eNB1 based on the Measurement Report received from the terminal device UE (S12). . In FIG. 9, it is assumed that the handover processing unit 21 determines in step S12 that the terminal apparatus UE is to be handed over to the radio base station eNB1.

  When the handover processing unit 21 of the radio base station eNB2 determines to hand over the terminal device UE to the radio base station eNB1, the HO request and the base station function information Dat2 are sent to the radio base station eNB1 by X2AP. Each part of the radio base station eNB2 is controlled so as to transmit (S13). In the present embodiment, it is assumed that the handover processing unit 21 stores the base station function information Dat2 in a predetermined field of the HO request and transmits it to the radio base station eNB1. However, the handover processing unit 21 may transmit the base station function information Dat2 to the radio base station eNB1 as a message separate from the HO request. The HO request includes HO Prep Info having ue-ConfigRelease indicating a release to which each function of the radio base station eNB2 complies.

  As illustrated in FIG. 9, the radio base station eNB1 is a process of determining whether to perform Full Configuration based on the base station function information Dat2 transmitted from the radio base station eNB2 in Step S13. Execution determination processing is executed (S14).

FIG. 10 is a flowchart showing the operation of the radio base station eNB1 when the full configuration execution determination process in step S14 is executed.
As illustrated in FIG. 10, the information acquisition unit 11 of the radio base station eNB1 acquires the base station function information Dat2 transmitted from the radio base station eNB2 in step S13 (S100). Specifically, the information acquisition unit 11 temporarily stores the base station function information Dat2 in the storage unit 110.
Next, the determination unit 12 of the radio base station eNB1 has the radio base station eNB2 based on the base station function information Dat1 stored in the storage unit 110 and the base station function information Dat2 acquired in step S100. A function presence / absence determination process, which is a process of determining whether or not a function that the radio base station eNB1 does not exist among the functions being performed, is executed (S110). Details of the function presence / absence determination process and details of the base station function information Dat1 and Dat2 will be described later.
And when the determination result of step S110 is affirmative, the instruction | indication part 13 of the wireless base station eNB1 produces | generates the information which instruct | indicates implementation of Full Configuration (S120). Specifically, in step S120, the instruction unit 13 sets the terminal device UE for communication between fullConfig-r9, which is information for instructing execution of Full Configuration, and the radio base station eNB1 that is the target radio base station. An HO command including information indicating a configuration to be generated is generated.
On the other hand, when the determination result of step S110 is negative, the instruction unit 13 of the radio base station eNB1 generates information for instructing execution of Delta Configuration (S130). Specifically, in step S130, the instruction unit 13 sets the configuration set in the terminal device UE for communication with the radio base station eNB2 that is the source radio base station, and the radio base station that is the target radio base station. Difference information between the configuration to be set in the terminal device UE for communication with the eNB 1 is generated, and an HO command including the difference information is generated.

  As illustrated in FIG. 9, the control unit 10 of the radio base station eNB1 transmits the HO request Ack including the HO command generated in step S120 or S130 to the radio base station eNB2. Each part is controlled (S15).

  The handover processing unit 21 of the radio base station eNB2 transmits RRC Connection Reconfiguration (RRC Conn Reconf) including the HO command transmitted from the radio base station eNB1 to the terminal device UE (S16).

When receiving the RRC Conn Reconf, the terminal device UE sets a configuration for performing communication with the radio base station eNB1 based on the HO command included in the RRC Conn Reconf (S17).
Specifically, in step S17, when the determination result in step S110 is affirmative and the instruction unit 13 instructs execution of Full Configuration, the terminal device UE excludes information related to C-RNTI and security. While deleting the configuration related to the communication with the radio base station eNB2, the configuration for performing the communication with the radio base station eNB1 is set based on the HO command included in the RRC Conn Reconf.
On the other hand, in Step S17, when the determination result in Step S110 is negative and the instruction unit 13 instructs execution of Delta Configuration, the terminal device UE is based on the difference information of the HO command included in the RRC Conn Reconf. The configuration for performing communication with the radio base station eNB1 is set.

Next, the terminal device UE transmits RRC Connection Reconfiguration Complete indicating that the configuration setting related to communication with the radio base station eNB1 is completed to the radio base station eNB1 (S18). Thereby, a bearer is established between the terminal device UE and the radio base station eNB1.
Thereafter, the terminal device UE transmits user data (Packet Data) to the upper node ND via a bearer established between the terminal device UE and the radio base station eNB1, or the user data is transmitted to the upper node. Received from the ND (S19).

<< 2.2. Function presence / absence judgment processing >>
Hereinafter, the function presence / absence determination process executed in step S110 will be described with reference to FIGS.

FIG. 11 is an explanatory diagram for explaining a function presence / absence determination process when the radio base station eNB1 and the radio base station eNB2 have different functions. In FIG. 11, it is assumed that the radio base station eNB1 operating as the target radio base station complies with Release 11, and the radio base station eNB2 operating as the source radio base station complies with Release 12. In FIG. 11, the radio base station eNB1 has a function F [1] compliant with release 9, a function F [2] compliant with release 10, and a function F [3] compliant with release 11. Then, it is assumed that the radio base station eNB2 has a function F [4] based on Release 12 in addition to the functions F [1] to F [3].
In the following, as shown in FIG. 11, when the source radio base station is a newer release than the target radio base station, and the source radio base station has a function that the target radio base station does not have, This is referred to as the “first case”.

As shown in FIG. 11, in this embodiment, the base station function information Dat indicating the function of the radio base station eNB may be implemented for a plurality of radio base stations eNB provided in the radio communication system SYS. A certain function F [1] to F [M] and M flags Flag corresponding one-to-one (M is a natural number of 2 or more).
In the present embodiment, in the base station function information Dat indicating the function possessed by one radio base station eNB, “1” is set in the flag Flag corresponding to the function F [m] possessed by the one radio base station eNB. (M is a natural number satisfying 1 ≦ m ≦ M). Further, in the base station function information Dat indicating the function of one radio base station eNB, the function F [m implemented in any one of the plurality of radio base stations eNB provided in the radio communication system SYS In other words, “0” is set in the flag Flag corresponding to the function F [m] that the one radio base station eNB does not have. Further, in the base station function information Dat indicating the function of one radio base station eNB, a flag corresponding to the function F [m] that is not implemented in any of the plurality of radio base stations eNB provided in the radio communication system SYS “Null” is set in the Flag, for example, the Flag Flag corresponding to the function F [m] that may be implemented in any radio base station eNB in the future.
However, the data format of the base station function information Dat in the present embodiment is merely an example, and the base station function information Dat has any data format as long as it can indicate the functions provided in each radio base station eNB. May be.

  In FIG. 11, the functions F [1] to F [4] are functions implemented in any of the plurality of radio base stations eNB provided in the radio communication system SYS, and the functions F [5] to F [M ] Is assumed to be a function that is not implemented in any of the plurality of radio base stations eNB provided in the radio communication system SYS. In FIG. 11, it is assumed that the radio base station eNB1 has functions F [1] to F [3] and the radio base station eNB2 has functions F [1] to F [4]. . Therefore, in FIG. 11, “1” is set in the flag Flag corresponding to each of the functions F [1] to F [3] in the base station function information Dat1, and the flag corresponding to the function F [4]. The flag is set to “0”, and the flag Flag corresponding to each of the functions F [5] to F [M] is set to “Null”. In the base station function information Dat2, “1” is set in the flag Flag corresponding to each of the functions F [1] to F [4], and each of the functions F [5] to F [M] is supported. “Null” is set in the flag Flag to be executed.

The determination unit 12 according to the present embodiment is a function F [m] corresponding to the flag Flag set to “0” in the base station function information Dat1 in the function presence / absence determination process in step S110, and the base station function When there is a function F [m] corresponding to the flag Flag set to “1” in the information Dat2, it is determined that the radio base station eNB2 has a function that the radio base station eNB1 does not have (S110). ; YES).
In FIG. 11, the flag Flag corresponding to the function F [4] in the base station function information Dat1 is set to “0”, and the flag Flag corresponding to the function F [4] in the base station function information Dat2 is “1”. Therefore, the determination result in step S110 is affirmative, and handover with full configuration is executed.

FIG. 12 shows a case where the radio base stations eNB1 and eNB2 conform to the same release, the radio base stations eNB1 and eNB2 have the same function, and the functions of the radio base stations eNB1 and eNB2 FIG. 10 is an explanatory diagram for explaining a function presence / absence determination process in a case where a function based on a release newer than a release based on the radio base stations eNB1 and eNB2 is included. In FIG. 12, it is assumed that both the radio base station eNB1 operating as the target radio base station and the radio base station eNB2 operating as the source radio base station comply with Release 11. Further, in FIG. 12, the radio base stations eNB1 and eNB2 have a function F [1] compliant with Release 9, a function F [2] compliant with Release 10, a function F [3] compliant with Release 11, It is assumed that the function F [4] conforming to the release 12 is included. That is, in FIG. 12, the radio base stations eNB1 and eNB2 have a function F [4] that conforms to a release “12” that is newer than the release “11” that the radio base stations eNB1 and eNB2 conform to.
In the following, as shown in FIG. 12, when the source radio base station and the target radio base station conform to the same release, the source radio base station and the target radio base station have the same function, and When the functions of the source radio base station and the target radio base station include a function that conforms to a release that is newer than the release that the source radio base station and the target radio base station conform to, ".

  In FIG. 12, in the base station function information Dat1 and Dat2, the flag Flag corresponding to each of the functions F [1] to F [4] is set to “1”, and the functions F [5] to F [M] “Null” is set in the flag Flag corresponding to each.

The determination unit 12 according to the present embodiment is a function F [m] corresponding to the flag Flag set to “0” in the base station function information Dat1 in the function presence / absence determination process in step S110, and the base station function When there is no function F [m] corresponding to the flag Flag set to “1” in the information Dat2, it is determined that the radio base station eNB1 has all the functions of the radio base station eNB2 (S110). NO).
In FIG. 12, the flag Flag corresponding to each of the functions F [1] to F [4] in the base station function information Dat1 is set to “1”, and the functions F [1] to F of the base station function information Dat2 are set. Since the flag Flag corresponding to each of [4] is set to “1”, the determination result in step S110 is negative, and handover with Delta Configuration is executed.

<< 2.3. Contrast with conventional handover >>
Hereinafter, in order to clarify the effect in the present embodiment, the handover according to the conventional operation mode described in FIGS. 1 and 2 (hereinafter referred to as “conventional example”) is the first described in FIGS. 11 and 12. A case of executing in the second case and the second case will be described.

  As described with reference to FIGS. 1 and 2, in the conventional example, whether or not Full Configuration is necessary is determined based on ue-ConfigRelease. Therefore, in the first case illustrated in FIG. 11, when the handover according to the conventional example is executed, the latest value “12” of the release indicated by ue-ConfigRelease is newer than the release “11” of the radio base station eNB1, A handover with full configuration will be executed. Also, in the second case illustrated in FIG. 12, even when handover is performed according to the conventional example, the latest release value “12” indicated by ue-ConfigRelease is newer than the release “11” of the radio base station eNB1. , Handover with Full Configuration is executed.

  On the other hand, in the present embodiment, as described above, in the first case illustrated in FIG. 11, handover with Full Configuration is executed, whereas in the second case illustrated in FIG. Perform handover with Configuration. That is, in the present embodiment, when the target radio base station can understand the configuration set in the terminal device UE for communication with the source radio base station, as in the second case illustrated in FIG. Thus, handover by Delta Configuration can be executed while avoiding implementation of Full Configuration. In other words, in this embodiment, as in the second case illustrated in FIG. 12, when Full Configuration is not necessary, it is possible to execute handover by Delta Configuration while avoiding implementation of Full Configuration.

<< 3. Effects of the first embodiment >>
In general, handover with Full Configuration notifies the terminal device UE of the entire configuration for communication with the target radio base station, so the data size of RRC Conn Reconf is larger than that with handover with Delta Configuration. Become. For this reason, the handover with Full Configuration has a longer RRC Conn Reconf transmission time than the handover with Delta Configuration, and the success probability of handover may be reduced.
On the other hand, since the radio base station eNB1 according to the present embodiment performs handover by Delta Configuration when Full Configuration is unnecessary, the success probability of handover due to execution of unnecessary Full Configuration It is possible to suppress the decrease.

In addition, since handover with Full Configuration has a larger RRC Conn Reconf data size than handover with Delta Configuration, there is a high possibility that radio resources that can be used in the user plane will be constrained.
On the other hand, since the radio base station eNB1 according to the present embodiment performs handover by Delta Configuration when Full Configuration is not required, radio resources are tight due to execution of unnecessary Full Configuration. It is possible to reduce the possibility of being performed.

Further, the handover with Full Configuration deletes the configuration related to the communication between the terminal apparatus UE and the source radio base station, so that user data transmitted from the terminal apparatus UE to the source radio base station is transferred from the terminal apparatus UE to the target radio. There are cases where it is necessary to retransmit to the base station.
On the other hand, the radio base station eNB1 according to the present embodiment suppresses occurrence of retransmission of user data from the terminal apparatus UE to the target radio base station because handover is performed by Delta Configuration when Full Configuration is not required. It becomes possible to do.

<< B. Second Embodiment >>
Hereinafter, a second embodiment of the present invention will be described. In addition, about the element whose effect | action and function are the same as that of 1st Embodiment in each form and each modification illustrated below, the detailed description of each is abbreviate | omitted suitably using the code | symbol used in 1st Embodiment. To do.

  In the first embodiment described above, the full configuration execution determination process for determining whether or not to perform Full Configuration is executed based on the base station function information Dat2 without using ue-ConfigRelease. On the other hand, in the second embodiment, the full configuration execution determination process is executed based on ue-ConfigRelease in addition to the base station function information Dat2.

  FIG. 13 is a functional block diagram illustrating a configuration of the radio base station eNB1-A according to the second embodiment. In 2nd Embodiment, the case where the terminal device UE is handed over from radio base station eNB2 to radio base station eNB1-A is assumed. Note that the hardware configuration of the radio base station eNB1-A is the same as that of the radio base station eNB1 according to the first embodiment shown in FIG. In the second embodiment, a plurality of radio base stations eNB included in the radio communication system SYS includes the radio base station eNB1-A.

  As shown in FIG. 13, the radio base station eNB1-A according to the first embodiment shown in FIG. 4 in that the storage unit 110 stores the control program PRG1-A instead of the control program PRG1. It is different from the radio base station eNB1. The radio base station eNB1-A includes a control unit 10A that is a function realized by the processor 1000 executing the control program PRG1-A. The control unit 10A is provided with a release information comparison unit 14 that compares a release indicated by ue-ConfigRelease transmitted from the radio base station eNB2 and a release that the radio base station eNB1-A complies with, in the first embodiment. It differs from the control part 10 with which the radio base station eNB1 which concerns is comprised.

  FIG. 14 is a flowchart showing the operation of the radio base station eNB1-A when the full configuration execution determination process according to the second embodiment is executed. In addition, in the handover according to the second embodiment, in step S14 shown in FIG. 9, the second implementation shown in the flowchart of FIG. 14 is performed instead of the full configuration execution determination process according to the first embodiment shown in the flowchart of FIG. This is the same as the handover according to the first embodiment except that the full configuration execution determination process according to the embodiment is executed. Further, the flowchart shown in FIG. 14 is the same as the flowchart shown in FIG. 10 except that step S200 is included instead of step S100, and step S210 is included. The description will be omitted as appropriate.

As illustrated in FIG. 14, the information acquisition unit 11 of the radio base station eNB1-A acquires the base station function information Dat2 and ue-ConfigRelease included in the HO request transmitted from the radio base station eNB2 in step S13. (S200).
Next, the release information comparison unit 14 of the radio base station eNB1-A indicates that the latest release that the function of the radio base station eNB2 indicated by ue-ConfigRelease acquired in step S200 is compliant is the radio base station eNB1-A. It is determined whether the release is newer than the compliant release (S210).
When the latest release indicated by ue-ConfigRelease is newer than the release that the radio base station eNB1-A complies with (an example of “when a predetermined condition is satisfied”), the release information comparison unit 14 (S210 YES), the process proceeds to step S110. As described above, in step S110, the function presence / absence determination, which is a process of determining whether or not the function that the radio base station eNB1-A has among the functions that the radio base station eNB2 has is present. Processing is executed.
On the other hand, if the latest release indicated by ue-ConfigRelease is not newer than the release that the radio base station eNB1-A complies with (S210; NO), the release information comparison unit 14 advances the process to step S130.

  As described above, the radio base station eNB1-A according to the present embodiment performs the function presence / absence determination process when the latest release indicated by ue-ConfigRelease is newer than the release to which the radio base station eNB1-A complies. Execute. For this reason, even if the latest release indicated by ue-ConfigRelease is newer than the release compliant with the radio base station eNB1-A, if Full Configuration is not necessary, avoid performing Full Configuration, Handover by Delta Configuration can be executed.

<< C. Modification >>
Each of the above forms can be variously modified. Specific modifications are exemplified below. Two or more aspects arbitrarily selected from the following examples can be appropriately combined within a range that does not contradict each other. In addition, about the element which an effect | action and a function are equivalent to embodiment in the modification illustrated below, the code | symbol referred by the above description is diverted and each detailed description is abbreviate | omitted suitably.

<< Modification 1 >>
In the embodiment described above, the base station function information Dat is information for managing presence / absence of functions in each radio base station eNB for all functions implemented in a plurality of radio base stations eNB provided in the radio communication system SYS. However, the present invention is not limited to such an aspect, and the base station function information Dat is a part of functions implemented in a plurality of radio base stations eNB provided in the radio communication system SYS. May be information for managing the presence or absence of a function in each radio base station eNB. For example, the base station function information Dat may be information for managing the presence / absence of a function in each radio base station eNB targeting only functions corresponding to information elements having a predetermined property.

Hereinafter, as illustrated in FIG. 15, information elements included in the configuration related to communication with the radio base station eNB set in the terminal device UE are classified into the following three types according to the properties of the information elements.
The first type of information element is an information element that is deleted by the terminal apparatus UE at the time of executing handover with Full Configuration, and is autonomous by the terminal apparatus UE at the time of executing handover with Delta Configuration. An information element to be deleted. For example, information elements belonging to the first type may include information elements whose Conditional Presence is set to “Need OR” and altCQI-Table-r12. In addition, when Conditional Presence of the information element is set to “Need OR”, the terminal apparatus UE deletes the setting of the information element in the handover with Delta Configuration.
The second type of information element is an information element that is deleted by the terminal apparatus UE at the time of executing handover with Full Configuration, and the setting at the terminal apparatus UE is maintained at the time of executing handover with Delta Configuration. Information element. That is, the second type of information element is an information element that is not a target of autonomous deletion by the terminal device UE when executing a handover with Delta Configuration. For example, as the information element belonging to the second type, an information element in which Conditional Presence is set to “Need ON” can be exemplified. In addition, when Conditional Presence of the information element is set to “Need ON”, the terminal device UE maintains the setting of the information element in the handover with Delta Configuration.
The third type of information element is an information element in which the setting in the terminal apparatus UE is maintained at the time of execution of handover with Full Configuration, and is set in the terminal apparatus UE even at the time of execution of handover with Delta Configuration. Is an information element that is maintained. For example, as information elements belonging to the third type, C-RNTI and information related to security can be exemplified.

In the base station function information Dat according to the above-described embodiment, functions corresponding to all information elements belonging to the first to third types are set as management targets of presence / absence of functions in each radio base station eNB (in FIG. 15). “Subject 1”). On the other hand, the base station function information Dat according to the present modified example has functions corresponding to information elements belonging to some of the first to third types as to whether or not there is a function in each radio base station eNB. It becomes management object.
Specifically, the base station function information Dat according to the present modification includes at least a function corresponding to the information element belonging to the second type as a management target of the presence / absence of the function in each radio base station eNB, and at least the first The function corresponding to the information element belonging to the type 1 is excluded from the management target of the presence or absence of the function in each radio base station eNB.
For example, the base station function information Dat is a function corresponding to the information element belonging to the second type or the third type, as in “Target 2” in FIG. The function corresponding to the information element belonging to the first type may be excluded from the management target of the presence / absence of the function in each radio base station eNB.
Further, for example, the base station function information Dat has a function corresponding to the information element belonging to the second type as a “target 3” in FIG. 15 as a management target of the presence / absence of the function in each radio base station eNB, The function corresponding to the information element belonging to the first type or the third type may be excluded from the management target of the presence / absence of the function in each radio base station eNB.
In the present modification, when the base station function information Dat excludes the predetermined function from the management target of the presence / absence of the function in the radio base station eNB, “Null” is set in the flag Flag corresponding to the predetermined function. It will be set.

Hereinafter, the function presence / absence determination process in the present modification will be described with reference to FIG.
In FIG. 16, it is assumed that the radio base station eNB1 operating as the target radio base station complies with Release 11, and the radio base station eNB2 operating as the source radio base station complies with Release 12. In addition, the radio base station eNB1 has a function F [1] compliant with Release 9, a function F [2] compliant with Release 10, and a function F [3] compliant with Release 11, Assume that the station eNB2 has a function F [4] based on Release 12 in addition to the functions F [1] to F [3]. The functions F [1] to F [3] are functions corresponding to information elements belonging to the second type, and the function F [4] is a function corresponding to information elements belonging to the first type. Assume that the functions F [5] to F [M] are functions that are not implemented in the wireless communication system SYS. That is, in FIG. 16, the function F [4] that is a function that the radio base station eNB1 does not have among the functions that the radio base station eNB2 has is a function that corresponds to the information element that belongs to the first type. Suppose.
In the following, a case where the function that the target radio base station does not have among the functions that the source radio base station has as shown in FIG. 16 is a function that corresponds to the information element belonging to the first type, This is referred to as “Case 3”.
In FIG. 16, the radio base station eNB1 is illustrated as an example of the target radio base station. However, the present modification is not limited to such an aspect, and the radio base station eNB1- A may be adopted.

In FIG. 16, among the base station function information Dat1, the flag Flag corresponding to each of the functions F [1] to F [3] corresponding to the information element belonging to the second type is set to “1”. “Null” is set in the flag Flag corresponding to the function F [4] corresponding to the information element belonging to one type. Also for the base station function information Dat2, the flag Flag corresponding to each of the functions F [1] to F [3] corresponding to the information elements belonging to the second type is set to “1”, and the first “Null” is set in the flag Flag corresponding to the function F [4] corresponding to the information element belonging to the type.
Therefore, the determination unit 12 according to this modification determines that the radio base station eNB1 has all the functions of the radio base station eNB2 in the function presence / absence determination process in step S110. As a result, the determination result in step S110 is negative, and handover with Delta Configuration is executed.

  In the third case illustrated in FIG. 16, when the handover according to the conventional example is executed, the latest release value “12” indicated by ue-ConfigRelease is newer than the release “11” of the radio base station eNB1, A handover with full configuration will be executed.

  As described above, according to the first modification, the function corresponding to the information element belonging to the first type deleted in the handover with Delta Configuration is provided in the source radio base station, and the target radio base station In the case where it is not provided, it is possible to execute the handover by the Delta Configuration while avoiding the implementation of the Full Configuration.

<< Modification 2 >>
In the embodiment and the modification described above, the radio base station eNB1 (or eNB1-A) acquires the base station function information Dat2 from the radio base station eNB2 after the radio base station eNB2 starts handover. Is not limited to such an embodiment.
For example, the radio base station eNB1 (or eNB1-A) may acquire the base station function information Dat2 from a database that manages the base station function information Dat of each radio base station eNB. Here, the database for managing the base station function information Dat may be provided in the upper node ND, may be provided in an OAM (Operationing and Management) system, or exists outside the wireless communication system. It may be provided in an external server.
Also, the radio base station eNB1 (or eNB1-A) acquires the base station function information Dat2 from the radio base station eNB2, for example, by exchanging information during X2 Setup before the radio base station eNB2 starts handover. May be.

<< Modification 3 >>
In the embodiment and the modification described above, the X2 handover performed between the radio base stations eNB is exemplified as the handover. However, the present invention is not limited to such an aspect, and the S1 handover performed via the MME. It may be. In this case, the base station function information Dat of the source radio base station is transmitted from the source radio base station to the target radio base station via the MME communicating with the source radio base station and the MME communicating with the target radio base station. It only has to be supplied.

<< Modification 4 >>
The hardware configurations of the radio base station eNB1, the radio base station eNB2, and the terminal device UE described in FIGS. 6 to 8 are examples, and can be variously modified.

For example, in the embodiment and the modification described above, the radio base station eNB1 and eNB1-A include a single processor 1000, but may include a plurality of processors 1000. In this case, various processes executed in the control unit 10 or 10A may be executed simultaneously or sequentially by the plurality of processors 1000.
Similarly, in the embodiment and the modification described above, the radio base station eNB2 includes a single processor 2000, but may include a plurality of processors 2000, and various processes executed in the control unit 20 include a plurality of processes. It may be executed simultaneously or sequentially by the processor 2000.

The processors 1000, 2000, and 3000 include hardware such as a DSP (Digital Signal Processor), an FPGA (Field Programmable Gate Array), a PLD (Programmable Logic Device), an ASIC (Application Specific Integrated Circuit), and a microprocessor. It may be comprised including. In this case, some or all of the functions realized by the processors 1000, 2000, and 3000 may be realized by hardware such as a DSP.
Further, the processors 1000, 2000, and 3000 may be mounted on a single chip or a plurality of chips.

  The memories 1001, 2001, and 3001 may be any computer-readable recording medium. For example, ROM (Read Only Memory), EPROM (Erasable Programmable ROM), EEPROM (Electrically Erasable Programmable ROM), RAM (Random (Access Memory) or the like. The memories 1001, 2001, and 3001 may be referred to as registers, caches, main memory (main storage device), or the like.

  The storages 1002, 2002, and 3002 may be any computer-readable recording medium, such as an optical disc such as a CD-ROM (Compact Disc ROM), a hard disc drive, a flexible disc, or a magneto-optical disc (eg, a compact disc). Disk, digital versatile disk, Blu-ray (registered trademark) disk, smart card, flash memory (for example, card, stick, key drive), floppy (registered trademark) disk, magnetic strip, etc. It may be configured by one. The storages 1002, 2002, and 3002 may be referred to as auxiliary storage devices.

  The communication devices 1005, 2005, and 3005 may be hardware (transmission / reception devices) for performing communication via one or both of a wired network and a wireless network. Note that the communication apparatuses 1005, 2005, and 3005 may be referred to as network devices, network controllers, network cards, or communication modules.

  The input devices 1003, 2003, and 3003 are input devices that accept input from the outside, such as a keyboard, a mouse, a microphone, a switch, a button, and a sensor. The output devices 1004, 2004, and 3004 are output devices that perform output to the outside, such as a display, a speaker, and an LED lamp. Note that the input device and the output device may be configured as a single unit, such as a touch panel.

<< Modification 5 >>
In the embodiment and the modification described above, the case where the wireless communication system SYS is a wireless communication system compliant with the LTE standard is exemplified. However, the present invention is not limited to such a mode, and the wireless communication system SYS is used. May be a fourth or later generation wireless communication system such as LTE-Advanced.

<< Modification 6 >>
In the embodiment and the modification described above, the case where the terminal device UE such as a mobile phone or a smartphone capable of wireless communication with the wireless base station is handed over from the source wireless base station to the target wireless base station has been described as an example. The present invention is not limited to such an aspect, and can be widely applied when the communication destination of a terminal device capable of communicating with a communication device is switched from a certain communication device to the certain different wireless device.
Here, as the terminal device, in addition to “User Equipment” such as a mobile phone or a smartphone, a personal computer having a communication function, a network device, and other communication devices in general can be employed. In addition to the radio base station eNB, devices such as S-GW and MME that are higher-level nodes ND, server devices having a communication function, and the like can be employed as communication devices that can communicate with terminal devices. Further, communication between the terminal device and the communication device is not limited to wireless communication, and may be wired communication.

DESCRIPTION OF SYMBOLS 10 ... Control part, 11 ... Information acquisition part, 12 ... Determination part, 13 ... Instruction part, 20 ... Control part, 21 ... Handover processing part, eNB1 ... Radio base station, eNB2 ... Radio base station.

Claims (5)

A wireless base station capable of wireless communication with a terminal device,
When handing over the terminal device from another radio base station to the radio base station,
A determination unit for determining whether or not the other radio base station has a function different from the function of the radio base station;
If the result of the determination is affirmative,
An instruction unit that instructs the terminal device to delete setting information related to wireless communication with the other wireless base station,
Comprising
A wireless base station characterized by that. The other radio base station is
Notifying the radio base station of base station function information indicating a function corresponding to setting information that the terminal apparatus does not autonomously delete in the handover among setting information related to radio communication between the terminal apparatus and the other radio base station And
The determination unit
Making the determination based on the base station function information;
The radio base station according to claim 1, wherein: An acquisition unit for acquiring type information indicating the type of the other radio base station;
The determination unit
The determination is performed when the type indicated by the type information satisfies a predetermined condition.
The radio base station according to claim 1 or 2, wherein The instruction unit includes:
If the result of the determination is negative,
Notifying the terminal device of information representing a difference between setting information related to wireless communication with the other wireless base station and setting information for performing wireless communication with the wireless base station,
The radio base station according to claim 1, wherein the radio base station is any one of claims 1 to 3. A communication device capable of communicating with a terminal device,
When switching the communication destination of the terminal device communicating with another communication device to the communication device,
A determination unit that determines whether the other communication device has a function different from the function of the communication device;
If the result of the determination is affirmative,
An instruction unit that instructs the terminal device to delete setting information related to communication with the other communication device;
Comprising
A communication device.

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