Patent Publication Number: US-2021185751-A1

Title: Communication apparatus, control method for communication apparatus, and non-transitory computer-readable storage medium

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a Continuation of International Patent Application No. PCT/JP2019/039902, filed Oct. 9, 2019, which claims the benefit of Japanese Patent Application No. 2018-196884, filed Oct. 18, 2018, both of which are hereby incorporated by reference herein in their entirety. 
    
    
     BACKGROUND OF THE INVENTION 
     Field of the Invention 
     The present invention relates to a communication apparatus, a control method for a communication apparatus, and a non-transitory computer-readable storage medium. 
     Background Art 
     The 3rd generation partnership project (3GPP) release 12 (Rel-12) standard specifies Dual connectivity (DC) that allow simultaneous communication with a plurality of base stations. The Dual connectivity allows User Equipment (UE) to perform simultaneous transmission using Component Carriers (CCs) provided by the plurality of base stations, thus increasing the user throughput (PTL1). Specifically, the UE divides one Evolved Packet System (EPS) bearer or packet sequence, and simultaneously transmits the divided packet sequences to the CCs provide by the plurality of base stations. More specifically, the UE transmits the divided packet sequences to a master base station serving as a master node (MN), and a secondary base station serving as a secondary node (SN). After receiving the packets, the master base station or the secondary base station reconfigures the packet sequences from the UE by reordering its own received packet sequence, and the packet sequence received from the other base station. After reconfiguring the packet sequence, the master base station or the secondary base station transfers the reconfigured packet sequence to a core node (CN). 
     5G which is the next generation communication standard currently being formulated in 3GPP, also specifies DC that can be used in a non-standalone mode in which 5G and Long Term Evolution (LTE), which are different wireless systems, cooperate with each other. This allows UE to simultaneously perform LTE communication and 5G communication, whereby the user throughput is improved. 
     CITATION LIST 
     Patent Literature 
     PTL 1: Japanese Patent Laid-Open No. 2016-127383 
     As described above, when UE simultaneously performs LTE communication and 5G communication, the performance can be expected to be enhanced by DC. On the other hand, the power consumption is expected to be increased as a result of performing data communication by simultaneously using communication circuits for the plurality of systems. For example, when a digital camera as UE uploads captured images to a server by simultaneously performing LTE communication and 5G communication, the digital camera may run out of battery earlier than when using only LTE communication. That is, when the digital camera is in the state of constantly activating DC, the digital camera may run out of battery early. This reduces the usability by the user because the image capturing function, which is the major function of the digital camera, can no longer be used. 
     SUMMARY OF THE INVENTION 
     In view of the above-described problem, the present disclosure provides a technique for controlling the function of Dual connectivity, taking power consumption into consideration. 
     According to one aspect of the present invention, there is provided a communication apparatus capable of performing data communication with one or more base stations, the apparatus comprises: a determination unit configured to determine whether or not to also perform communication with a secondary base station, in addition to a master base station, for the data communication; a measurement unit configured to measure a first quality, which is a quality of a signal received from the master base station, and a second quality, which is a quality of a signal received from the secondary base station; and a transmission unit configured to transmit a measurement report including the first quality and the second quality to the master base station in a case where it is determined by the determination unit to also perform communication with the secondary base station, and transmitting a measurement report including the first quality and not including the second quality to the master base station in a case where it is determined by the determination unit not to perform communication with the secondary base station. 
     Further features of the present invention will become apparent from the following description of exemplary embodiments with reference to the attached drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate embodiments of the invention and, together with the description, serve to explain principles of the invention. 
         FIG. 1  is a diagram showing an exemplary hardware configuration of a digital camera according to an embodiment. 
         FIG. 2  is a diagram showing an exemplary software functional configuration of the digital camera according to the embodiment. 
         FIG. 3  is a diagram showing an exemplary network configuration according to the embodiment. 
         FIG. 4  is an operation flowchart of DC start processing according to the embodiment. 
         FIG. 5  is an operation flowchart of DC stop processing according to the embodiment. 
         FIG. 6  is a diagram showing an operation sequence performed in the digital camera and two base stations according to the embodiment. 
     
    
    
     DESCRIPTION OF THE EMBODIMENTS 
     Hereinafter, the present invention will be described in detail based on an exemplary embodiment thereof. It should be appreciated that the configurations in the following embodiment are merely illustrative, and the present invention is not limited to the configurations shown in the drawings. 
     (Network Configuration) 
       FIG. 3  shows an exemplary network configuration according to the present embodiment. The network configuration shown in  FIG. 3  is composed of a digital camera  301 , an LTE base station  302 , and a 5G base station  303 . The LTE base station  302  is capable of performing communication in accordance with an LTE communication system conforming to a 3GPP standard, and the 5G base station  303  is capable of performing communication in accordance with a 5G communication system conforming to the 3GPP standard. The digital camera  301  serving as UE is located in each of the cells (communicable ranges) of the LTE base station  302  and the 5G base station  303 , and supports the Dual connectivity (DC) capability of simultaneously communicating with these base stations. In the present embodiment, the digital camera  301  transmits captured image data to the LTE base station  302  and the 5G base station  303  using DC in order to upload the captured image data to a network apparatus (not shown) such as a server connected to a core network  304 . The LTE base station  302  and the 5G base station  303  transmit the captured image data received from the digital camera  301  to the network apparatus (not shown) connected to the core network  304 . 
     In the present embodiment, the LTE base station  302  functions as a master base station (MN), and the 5G base station  303  functions as a secondary base station (SN). In DC communication, the LTE base station  302  serving as the master base station controls simultaneous communication between the digital camera  301 , and the LTE base station  302  and the 5G base station  303 , and also controls communication between the digital camera  301  and the upper core network  304 . 
     (Configuration of Digital Camera) 
       FIG. 1  shows an exemplary hardware configuration of the digital camera  301  according to the present embodiment. The digital camera includes, as an exemplary hardware configuration, a control unit  101 , a storage unit  102 , a wireless communication unit  103 , a display unit  104 , an antenna control unit  105 , an antenna  106 , an input unit  107 , and an image capturing unit  108 . The control unit  101  performs overall control of the digital camera  301  by executing a control program stored in the storage unit  102 . The storage unit  102  stores the control program executed by the control unit  101 , and various types of information such as captured image data, communication parameter(s), and authentication information. The communication parameter(s) and authentication information may be used when connecting with the LTE base station  302  and the 5G base station  303 . Various operations of the digital camera  301 , which will be described later, may be performed by the control unit  101  executing the control program stored in the storage unit  102 . The wireless communication unit  103  performs cellular network communication using LTE, 5G or the like, or wireless communication using Wi-Fi or the like. The display unit  104  has a function capable of outputting visually recognizable information, such as that of an LCD or an LED, or a function capable of outputting sound, such as that of a speaker, and performs various displays. The antenna control unit  105  controls the antenna  106  in order to perform wireless communication. The input unit  107  has an operational function for operating the digital camera  301 , and receives various inputs/operations or the like performed by the user. The input unit  107  and the display unit  104  may also be configured as a user interface (UI) by being combined so as to function together. The image capturing unit  108  has an image capturing function, and performs image capturing processing to generate captured image data. 
       FIG. 2  shows an exemplary software functional configuration of the digital camera  301  according to the present embodiment. The digital camera includes, as an exemplary software functional configuration, a transmission unit  201 , a reception unit  202 , a connection control unit  203 , a determination unit  204 , a measurement unit  205 , a DC control unit  206 , a display control unit  207 , and a data transfer control unit  208 . 
     The transmission unit  201  and the reception unit  202  each transmit signals (e.g., various types of messages/information and captured image data) to a counterpart apparatus via the wireless communication unit  103 , and receive signals (e.g., various types of messages/information). The connection control unit  203  performs control and management relating to connection with the LTE base station  302  and the 5G base station  303 . The determination unit  204  determines whether or not execution of DC by the digital camera  301  is necessary. The measurement unit  205  measures the quality of the radio environment by performing measurement processing for the signals received from the LTE base station  302  and the 5G base station  303  via the reception unit  202 . The DC control unit  206  controls execution of DC by the digital camera  301 , based on the signals or the like received by the reception unit  202 . For example, the DC control unit  206  determines, for example, whether or not execution of DC by the digital camera  301  is possible, or whether or not the digital camera  301  is executing DC, and performs processing according to the determination. The display control unit  207  performs control relating to displays on the display unit  104 . When the display unit  104  functions as an UI together with the input unit  107 , the display control unit  207  may perform control for that UI. The data transfer control unit  208  performs control and management of transmission (transfer) of the captured image data stored in the storage unit  102 . 
     (Flow of Processing) 
     Next, the operation of the digital camera  301  according to the present embodiment will be described with reference to  FIGS. 4 and 5 . First, DC start processing performed by the digital camera  301  will be described.  FIG. 4  is an operation flowchart of the DC start processing according to the present embodiment. First, the connection control unit  203  starts processing for connecting to a public network (network by the LTE base station  302 /5G base station  303 ) (S 401 ). Here, the connection control unit  203  starts the processing for connecting to the public network, for example, in response to an instruction given by the control unit  101 . The control unit  101  may instruct the connection control unit  203  to star the connection processing, based on a user operation performed on the input unit  107 . When the control unit  101  is executing an application for transferring captured image data, the control unit  101  may instruct the connection control unit  203  to start the connection processing at an appropriate timing in the program of the application being executed. Specifically, in S 401 , the connection control unit  203  controls the transmission unit  201  and the reception unit  202  so as to allow the digital camera  301  to perform communication using both the LTE and 5G communication systems. 
     Because the digital camera  301  is present in the cells of the LTE base station  302  and the 5G base station  303 , the reception unit  202  then receives broadcast information from each of the LTE base station  302  and the 5G base station  303  (S 402 ). After receiving broadcast information from each of the two base stations, the connection control unit  203  performs RRC connection processing for the LTE base station  302 , and establishes an RRC connection with the LTE base station  302 . Note that RRC is an abbreviation for radio resource control, which is a protocol for controlling a wireless network. After the RRC connection has been established, the transmission unit  201  transmits an attach request message (not shown) for authentication to the core network  304 . Here, the transmission unit  201  may include, in the attach request message, information indicating that the apparatus supports the DC capability. 
     Then, in S 404 , the determination unit  204  determines whether or not execution of DC by the digital camera  301  is necessary. For example, the determination is performed based on the form (condition) of data transmission scheduled to be performed via the established RRC connection. Specifically, if the data transmission requires high-speed communication, the determination unit  204  may determine that execution of DC is necessary. The data transmission that requires high-speed data communication is a form of data transmission that requires time to complete the data communication if ordinary data communication is used, including, for example, uploading of a high-resolution image or a large amount of moving images. The determination unit  204  may also determine that execution of DC is necessary if the data transmission requires redundant communication using a plurality of communication paths. The data transmission that requires redundant communication using a plurality of communication paths is a form of data transmission, including, for example, real-time video transmission. As an implementation in which the above-described determination is performed based on the form (condition) of data transmission may be realized by the determination unit  204  determining, when the control unit  101  is executing an application for transferring captured image data, whether or not the application requires high-speed data communication, or whether or not the application requires redundant communication using a plurality of communication paths. Note that the determination performed by the determination unit  204  is not limited to those based on the form of data transmission. For example, the determination unit  204  may determine whether or not to execute DC, based on an instruction given by the user through the input unit  107 . For example, whether DC is to be enabled or disabled may be allowed to be set on a UI configured by the display unit  104  and the input unit  107  functioning together, and the determination unit  204  may determine that execution of DC is necessary in response to the user setting DC to be enabled. 
     If the determination unit  204  determines that execution of DC is not necessary (No in S 404 ), the reception unit  202  receives, in S 411 , from the LTE base station  302  serving as MN, an instruction to measure the reception quality (communication quality) for the signals from the base station around the digital camera  301 . Consequently, the measurement unit  205  is activated. Then, when broadcast information is received by the reception unit  202  from the LTE base station  302  and the 5G base station  303 , which are the surrounding base stations, the measurement unit  205  measures the reception quality of the signals of each of the base stations (each of the cells), based on the received broadcast information. For example, the measurement unit  205  measures the reference signal received power (RSRP), the reference signal received quality (RSRQ), and the signal-to-interference-plus-noise ratio (SINR). In S 413 , the transmission unit  201  transmits, as a measurement result, a measurement report including the reception quality measured in S 412 . Here, because it is determined that execution of DC in the digital camera  301  is not necessary (NO in S 404 ), the transmission unit  201  includes only the reception quality of the LTE base station  302  in the measurement report to be transmitted. That is, the transmission unit  201  transmits the measurement report without including therein the reception quality of the 5G base station  303 . If any LTE base station other than the LTE base station  302  is present around the digital camera  301 , the transmission unit  201  may include the reception quality of the other LTE base station in the measurement report. If any 5G base station other than the 5G base station  303  is present around the digital camera  301 , the transmission unit  201  does not also include the reception quality of the other 5G base station in the measurement report. After S 413 , the processing returns to S 404 , and the processing in S 404 , S 411 , S 412 , and S 413  is repeated until it is determined that execution of DC is necessary. In parallel with this, the digital camera  301  may transmit captured image data to the LTE base station  302  via the established RRC connection. 
     On the other hand, if the determination unit  204  determines that execution of DC is necessary (YES in S 404 ), the processing proceeds to S 405 . In S 405 , the reception unit  202  receives broadcast information from the base station around the digital camera  301 , and the measurement unit  205  measures the reception quality. The processing in S 405  is the same as the processing in S 412 , and therefore the description thereof is omitted. After the reception quality has been measured by the measurement unit  205 , the DC control unit  206 , in S 406 , analyzes the radio environment around the digital camera  301 , and determines whether or not execution of DC by the digital camera  301  is possible. For example, the DC control unit  206  determines whether or not execution of DC is possible, based on whether or not broadcast information has been successfully received from the 5G base station  303  by the reception unit  202  in S 405 . In this case, the DC control unit  206  determines that execution of DC is possible if broadcast information has been successfully received from the 5G base station  303  by the reception unit  202  in S 405 . Note that the 5G base station is not limited to the 5G base station  303 . If any 5G base station other than the 5G base station  303  is present in the surroundings, and the reception unit  202  can receive the broadcast information from the other 5G base station, the DC control unit  206  may determine that execution of DC is possible. 
     If it is determined that execution of DC is not possible (NO in S 406 ), the processing returns to S 405 , and the reception unit  202  again attempts to receive the broadcast information from the surrounding base station. If it is determined that execution of DC is possible (YES in S 406 ), the processing proceeds to S 407 . In S 407 , the transmission unit  201  transmits, as a measurement result, a measurement report including the reception quality to the base station. Here, because it is determined that execution of DC in the digital camera  301  is necessary (YES in S 404 ), the transmission unit  201  transmits the measurement report by including therein the reception quality of the LTE base station  302  and the reception quality of the 5G base station  303 . If any LTE base station other than the LTE base station  302  is present around the digital camera  301 , the transmission unit  201  may include the reception quality of the other LTE base station in the measurement report. Similarly, if any 5G base station other than the 5G base station  303  is present around the digital camera  301 , the transmission unit  201  may include the reception quality of the other 5G base station in the measurement report. After the transmission unit  201  has transmitted the measurement report, the processing proceeds to S 408 . 
     In S 408 , the reception unit  202  determines whether or not an RRC connection reconfiguration message has been received as a predetermined signal for reconfiguring the RRC connection. The RRC connection reconfiguration message here is a message transmitted by the LTE base station  302  to perform, in order to add the 5G base station  303  as a SN in DC, SN adding processing between the LTE base station  302  and the 5G base station  303 , and reconfigure (reconstruct) the RRC connection after completion of the processing. When the reception unit  202  receives the RRC connection reconfiguration message (YES in S 408 ), the processing proceeds to S 409 . In S 409 , the connection control unit  203  performs RRC connection reconfiguring processing by controlling the transmission unit  201  and the reception unit  202 , and completes the RRC reconfiguration. When the connection control unit  203  completes the RRC connection reconfiguring processing, the transmission unit  201  transmits, as a complete message, an RRC connection reconfiguration complete message to the LTE base station  302 . Then, the processing proceeds to S 410 , in which a random access procedure is performed as a synchronization establishing procedure between the digital camera  301  and the 5G base station  303 , whereby the digital camera  301  can perform data communication using DC via the established RRC connection. 
     After the processing in S 410 , the display control unit  207  may notify the user that DC has been started by displaying the notification on the display unit  104  (or the UI configured by the display unit  104  and the input unit  107  functioning together). In this case, the display control unit  207  may provide the notification to the user using a pop-up on the display unit  104  or the UI, or provide the notification using an icon. 
     If it has been determined before the processing in S 401  that execution of DC in the digital camera  301  is not necessary, the connection control unit  203 , in S 401 , may control the transmission unit  201  and the reception unit  202  so as to allow the digital camera  301  to perform communication using only the LTE communication system. In this case, before the reception unit  202  performs the processing for receiving the broadcast information in S 405 , the connection control unit  203  may control the transmission unit  201  and the reception unit  202  so as to allow the digital camera  301  to perform communication using both the LTE and 5G communication systems. 
     Next, the DC stop processing performed by the digital camera  301  will be described.  FIG. 5  is an operation flowchart of the DC stop processing according to the present embodiment. It is assumed that the digital camera  301  is performing data communication via a public network. First, the data transfer control unit  208  determines whether or not the data communication has ended (S 501 ). For example, when the control unit  101  is executing an application for transferring captured image data, the data transfer control unit  208  may determine that the data communication has ended, at a suitable timing in the program of the application, or in response to completion of the application. The data transfer control unit  208  may determine that the data communication has ended, based on a user instruction to the input unit  107 . If it is determined that the data communication has ended (YES in S 501 ), the processing proceeds to S 502 . 
     In S 502 , the DC control unit  206  determines whether or not the digital camera  301  is executing DC. The DC control unit  206  may determine whether or not DC is being executed, for example, according to the state of the transmission unit  201  and the reception unit  202 . If it is determined that DC is being executed (YES in S 502 ), the processing proceeds to S 503 . If it is determined that DC is not being executed (NO in S 502 ), the processing proceeds to S 508 . In S 503 , the DC control unit  206  determines to stop DC. In S 503 , rather than determining to stop DC, the DC control unit  206  may determine to continue DC, taking resumption of the data communication using DC into consideration. In that case, after resumption of the data communication, the digital camera  301  returns to S 501  to perform the determination processing again. 
     In S 504 , the reception unit  202  receives broadcast information from the surrounding base station, and the measurement unit  205  measures the reception quality. The processing in S 503  is the same as the processing in S 412  of  FIG. 4 , and therefore the description thereof is omitted. In S 505 , the transmission unit  201  then transmits the measurement report to the base station. Here, because it is determined to stop DC in the digital camera  301  (S 503 ), the transmission unit  201  transmits the measurement report by only including therein the reception quality of the LTE base station  302 . That is, the transmission unit  201  transmits the measurement report without including therein the reception quality of the 5G base station  303 . If any LTE base station other than the LTE base station  302  is present in the surrounding, the transmission unit  201  may include the reception quality of the other LTE base station in the measurement result. If any 5G base station other than the 5G base station  303  is present in the surroundings, the transmission unit  201  will not include the reception quality of the other 5G base station in the measurement result. Then, the processing proceeds to S 506 . 
     In S 506 , the reception unit  202  determines whether or not an RRC connection reconfiguration message has been received in the digital camera  301 . The RRC reconfiguration message here is a message transmitted by the LTE base station  302  after completion of processing performed for cancelling registration as SN in DC for the 5G base station  303 . When the reception unit  202  receives the RRC connection reconfiguration message (YES in S 506 ), the processing proceeds to S 507 . In S 507 , the connection control unit  203  performs the RRC connection reconfiguring processing by controlling the transmission unit  201  and the reception unit  202 , thus establishing an RRC connection only with the LTE base station  302 . When establishment of the RRC connection is completed, the random access procedure is performed as a synchronization establishing procedure between the digital camera  301  and the LTE base station  302 , whereby communication via the LTE base station  302  is performed. Then, the processing proceeds to S 508 . 
     After the processing in S 507 , the display control unit  207  may notify the user that DC has been stopped (that DC has been disconnected) by displaying the notification on the display unit  104  (or the UI configured by the display unit  104  and the input unit  107  functioning together). In this case, the display control unit  207  may provide the notification to the user using a pop-up on the display unit  104  or the UI, or provide the notification using an icon. 
     In S 508 , the connection control unit  203  determines whether or not a public network disconnection instruction is received. The connection control unit  203  may receive the public network disconnection instruction in accordance with a user instruction to the input unit  107 . When the control unit  101  is executing an application for transferring captured image data, the public network disconnection instruction may be given to the connection control unit  203  at an appropriate timing in the program of the application being executed. The connection control unit  203  may determine that the public network disconnection instruction is received, based on the occurrence of some error or the like in the digital camera  301 . In the state of S 508 , the processing may return to the processing for determining the necessity of execution of DC, which is the processing in S 404  shown in  FIG. 4 . In this case, the processing in S 405  to S 410  will be performed when execution of DC becomes necessary again (YES in S 404 ). If the connection control unit  203  receives the public network disconnection instruction (YES in S 508 ), the connection control unit  203  performs processing for disconnecting connection with the public network (S 509 ), and the public network connection of the digital camera  301  ends. 
     Next, the flow of signals during execution of DC according to the present embodiment will be described with reference to  FIG. 6 .  FIG. 6  shows a processing operation sequence at the time of execution of DC performed between the digital camera  301  and the LTE base station  302  and the 5G base station  303 . Note that  FIG. 6  shows a sequence necessary to describe the present embodiment. Not all of the sequences relating to the public network connection are described, and some of the sequences are omitted in the drawing. 
     First, the digital camera  301  starts a public network connection (F 601 ). In the present example, it is assumed that at the time when the digital camera  301  starts the public network connection, it is determined that execution of DC is not necessary. Then, the digital camera  301  receives the broadcast information (F 602 ) from the LTE base station  302 , and the broadcast information (F 603 ) from the 5G base station  303 . After receiving the broadcast information, the digital camera  301  connects to the LTE base station  302  by performing the RRC connection (F 604 ) processing. After completion of the connection, the digital camera  301  transmits an attach request message (not shown) for authentication to the core network. Here, the digital camera  301  may transmit the attach request message by including therein the fact that the digital camera  301  supports the DC capability. 
     Next, the digital camera  301  determines whether or not execution of DC is necessary (F 605 ). As described above, the digital camera  301  determines that execution of DC is not necessary at this point. Then, in response to receiving the measurement instruction (F 606 ) relating to the reception quality of the base station around the digital camera  301  from the LTE base station  302  serving as the MN, the digital camera  301  measures the reception quality based on a subsequently received broadcast information (not shown, the same as those in F 602 , F 603 ). After measuring the reception quality, the digital camera  301  transmits a measurement report including the reception quality (F 607 ). Because the digital camera  301  determines that execution of DC is not necessary at this point, the digital camera  301  transmits the measurement report by including therein only measurement result of the reception quality of the LTE base station  302 . 
     Upon receiving the measurement report from the digital camera  301 , the LTE base station  302  analyzes the content of the measurement report on the core network  304  side. At that time, because the measurement report includes only the reception quality of the LTE base station  302 , it is determined that the digital camera  301  cannot execute DC via the 5G base station  303 . As a result, an instruction to start DC will not be notified to the digital camera  301  from the LTE base station  302  serving as the MN, and DC will not be executed. 
     Here, it is assumed that execution of a “moving picture upload” application (service) is instructed by the user on the digital camera  301 , and execution of the application is started (F 608 ). Because the “moving picture upload” application requires a large amount of data communication, the digital camera  301  determines that execution of DC is necessary. Then, the digital camera  301  receives broadcast information (not shown, the same as those in F 602 , F 603 ) from the surrounding base station, measures the reception quality, and transmits a measurement report including the reception quality to the base station (F 610 ). Because the digital camera  301  determines that execution of DC is necessary at this time, the digital camera  301  transmits a measurement report including the reception quality of the LTE base station  302  and the reception quality of the 5G base station  303 . 
     Upon receiving the measurement report from the digital camera  301 , the LTE base station  302  analyzes the content of the measurement report on the core network  304  side. At that time, because the measurement report includes the reception quality of the 5G base station  303  in addition to the reception quality of the LTE base station  302 , it is determined that the digital camera  301  can execute DC via the 5G base station  303 . Then, in order to add the 5G base station  303  as a SN, the LTE base station  302  performs the SN adding processing (F 611 ) between the LTE base station  302  and the 5G base station  303 . Upon completion of the SN adding processing, in order to reconstruct the RRC connection with the digital camera  301 , the LTE base station  302  transmits an RRC connection reconfiguration message (F 612 ) to the digital camera  301 . 
     Upon receiving the RRC connection reconfiguration message, the digital camera  301  performs the RRC connection reconfiguring processing based on that message, whereby the reconstruction is completed. Upon completion of the reconstruction of the RRC connection, the digital camera  301  transmits, as a completion message, an RRC connection reconfiguration complete message (F 613 ) to the LTE base station  302 . 
     Upon receiving the RRC connection reconfiguration complete message from the digital camera  301 , the LTE base station  302  notifies the 5G base station  303  that the addition as a SN is completed (F 614 ). Upon completion of the processing for adding the 5G base station  303  as an SN in DC for the digital camera  301 , the random access procedure (F 615 ) is then performed as a synchronization establishing procedure. Thereafter, data communication using DC can be performed on the digital camera  301  via the LTE base station  302  and the 5G base station  303 . 
     In the above-described description, after starting the public network connection in F 601 , execution of the “moving picture upload” application is started in F 608 . However, this order may be reversed. That is, the digital camera  301  may perform a public network connection after execution of the “moving picture upload” application has been started. In this case, the digital camera  301  determines the necessity of execution of DC upon connecting to the LTE base station  302 , and transmits the measurement report by also including therein the reception quality of the 5G base station  303 , upon determination that execution of DC is necessary. This allows the digital camera  301  to notify the LTE base station  302  that the digital camera  301  is in the state of capable of executing DC, immediately after connecting to the public network. 
     As described thus far, according to the present embodiment, as for the measurement report used to determine whether or not DC is executed on the base station side, the information included in the measurement report is changed based on the condition on the User Equipment (UE) side. Thus, the activation of DC by the base station can be controlled. Accordingly, DC can be executable only when DC is necessary on the UE side, and it is possible to reduce unnecessary power consumption as compared with when DC is constantly executed, thus improving the ease of use for the user. 
     (Modification 1) 
     In the embodiment described above, the digital camera  301  transmits the measurement report upon determining that execution of DC is necessary. However, the timing for determining the necessity of execution of DC is not limited thereto. For example, the digital camera  301  may determine whether or not execution of DC is necessary each time when a measurement instruction is received from the LTE base station  302  serving as the MN. This make is possible to determine the necessity of execution of DC using, as a trigger for determining the necessity of execution of DC, not only the processing performed on the user equipment side, but also an instruction from the base station side. 
     (Modification 2) 
     In the embodiment described above, the digital camera  301  transmits measurement report without including therein the reception quality of the 5G base station  303 , if the digital camera  301  determines that execution of DC is not necessary. However, the operation performed when it is determined that execution of DC is not necessary is not limited thereto. For example, the digital camera  301  may notify the measurement result using a low value as the measurement value of the reception quality of the 5G base station  303  such that the LTE base station  302  as the MN determines not to execute DC. This allows the digital camera  301  to periodically notify the MN that the digital camera  301  supports the 5G communication. 
     (Modification 3) 
     In the embodiment described above, the digital camera  301  transmits the measurement report to the LTE base station  302 . However, the present invention is not limited thereto. For example, the digital camera  301  may transmit the measurement report to the LTE base station serving as the MN via the 5G base station  303  serving as the SN. 
     (Modification 4) 
     In the above embodiment, a case where the MN is an LTE base station, and the SN is a 5G base station is described. However, the present invention is not limited thereto. The MN may be a 5G base station, and the SN may be an LTE base station. In that case, the 5G base station and the LTE base station according to the present embodiment can be applied by being replaced with each other. 
     According to the present invention, it is possible to control the function of Dual connectivity, taking power consumption into consideration. 
     OTHER EMBODIMENTS 
     Embodiment(s) of the present invention can also be realized by a computer of a system or apparatus that reads out and executes computer executable instructions (e.g., one or more programs) recorded on a storage medium (which may also be referred to more fully as a ‘non-transitory computer-readable storage medium’) to perform the functions of one or more of the above-described embodiment(s) and/or that includes one or more circuits (e.g., application specific integrated circuit (ASIC)) for performing the functions of one or more of the above-described embodiment(s), and by a method performed by the computer of the system or apparatus by, for example, reading out and executing the computer executable instructions from the storage medium to perform the functions of one or more of the above-described embodiment(s) and/or controlling the one or more circuits to perform the functions of one or more of the above-described embodiment(s). The computer may comprise one or more processors (e.g., central processing unit (CPU), micro processing unit (MPU)) and may include a network of separate computers or separate processors to read out and execute the computer executable instructions. The computer executable instructions may be provided to the computer, for example, from a network or the storage medium. The storage medium may include, for example, one or more of a hard disk, a random-access memory (RAM), a read only memory (ROM), a storage of distributed computing systems, an optical disk (such as a compact disc (CD), digital versatile disc (DVD), or Blu-ray Disc (BD)™), a flash memory device, a memory card, and the like. 
     While the present invention has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. The scope of the following claims is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures and functions.