Patent Publication Number: US-2012034899-A1

Title: Communication method and mobile station

Description:
TECHNICAL FIELD 
     The present invention relates to a communication method and a mobile station. 
     BACKGROUND ART 
     A mobile station can be placed in a self mode, during which originating and receiving calls is restricted by disabling (turning off) a radio. The self mode is used as a consideration for medical devices and precision instruments or as a courtesy in hospitals, trains, airplanes, and so on. 
     During the self mode, reading received mails, modifying the configuration of the mobile station, gaming, and so on are typically allowed. However, communication by the mobile station over the network is not allowed, except for an emergency call to a police station, a fire department, or the like (see Japanese Patent Laid-Open Publication No. 2003-224878, for example). 
     DISCLOSURE OF INVENTION 
     Problem(s) to be Solved by the Invention 
     When a mobile station disables the radio during the self mode, in order to originate an emergency call, the mobile station needs to prepare for originating the emergency call according to a predetermined procedure. Specifically, the mobile station needs to enable (turn on) the radio, perform a carrier search, capture a cell after detecting the carrier, obtain broadcast information for the cell, and verify that the mobile station can originate an emergency call. Then, the mobile station originates the emergency call. For this reason, it takes time for a mobile station to originate an emergency call during the self mode. 
     In addition, when a mobile station disables the radio during the self mode, the mobile station cannot receive an emergency message such as ETWS (Earthquake and Tsunami Warning System) or CBS (cell broadcast service). Furthermore, the mobile station can neither receive a message for modifying broadcast information nor receive an incoming call requiring emergency attention. 
     In order to solve the problem related to the self mode, it is a general object of the present invention to allow a mobile station to receive an emergency incoming call such as ETWS during the self mode. 
     Means for Solving the Problem(s) 
     In one aspect of the present invention, there is provided a communication method in a mobile station, including the steps of: 
     placing the mobile station in a self mode; and 
     allowing the mobile station to receive a radio wave during the self mode. 
     In another aspect of the present invention, there is provided a mobile station, comprising: 
     a mode setting unit configured to place the mobile station in a self mode; and 
     a control unit configured to allow the mobile station to receive a radio wave during the self mode. 
     Advantageous Effect of the Invention 
     According to an embodiment of the present invention, a mobile station can receive an emergency incoming call such as ETWS during the self mode. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  shows a block diagram of a mobile station in accordance with an embodiment of the present invention. 
         FIG. 2  shows a sequence diagram of a procedure of placing a mobile station in the self mode in accordance with an embodiment of the present invention. 
         FIG. 3  shows a sequence diagram of a procedure of originating an emergency call and receiving an emergency incoming call in a mobile station in accordance with an embodiment of the present invention. 
         FIG. 4  shows an example of a paging message used in an embodiment of the present invention (in the case of LTE). 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     A self mode is used as a consideration for medical devices and precision instruments, as a courtesy in a public space, or the like. During the self mode, originating and receiving a call by a mobile station is restricted, and accordingly a radio wave is not transmitted from the mobile station. During the self mode, the radio (i.e., a receiver and a transmitter) in the mobile station is typically disabled. When the radio is disabled, in order to originate an emergency call to a police station, a fire department, or the like, the mobile station needs to enable the radio, perform a carrier search, capture a cell after detecting the carrier, obtain broadcast information for the cell, and verify that the mobile station can originate an emergency call. In addition, when the radio is disabled, the mobile station cannot receive an emergency incoming call. For example, the mobile station cannot receive an emergency message such as ETWS or CBS. Furthermore, the mobile station cannot receive an incoming call requiring emergency attention from a police station, a fire department, or the like. 
     According to an embodiment of the present invention, during the self mode, the transmitter in the mobile station is disabled and the receiver in the mobile station is enabled. Specifically, the mobile station is allowed to receive a radio wave during the self mode. Instead of disabling the transmitter in the mobile station during the self mode, a user interface associated with originating a call (except for an emergency call) may be deactivated during the self mode. By allowing the mobile station to receive a radio wave during the self mode, the mobile station can perform a carrier search or a cell reselection during the self mode and obtain broadcast information for the cell. Accordingly, the mobile station can shorten the time to originate an emergency call during the self mode. In addition, by enabling the receiver in the mobile station during the self mode, the mobile station can receive an emergency incoming call. As used herein, an emergency call is a call specified for use in an emergency. For example, an emergency call can be determined based on a telephone number which is registered in advance in the mobile station. As used herein, an emergency incoming call is an incoming call specified for use in an emergency. For example, the emergency incoming call can be determined based on whether a predetermined information element in a paging message indicates an emergency. An emergency incoming call includes an emergency message such as ETWS or CBS and an incoming call requiring emergency attention from a police station, a fire department, or the like. 
     &lt;Block Diagram of a Mobile Station&gt; 
       FIG. 1  shows a block diagram of a mobile station  10  in accordance with an embodiment of the present invention. The mobile station  10  includes a user interface  101 , a control unit  103 , a receiver  105 , and a transmitter  107 . 
     The user interface  101  accepts a setting request for establishing the self mode from a user to place the mobile station  10  in the self mode. The user interface  101  also accepts a release request for releasing the self mode from the user to release the self mode in the mobile station  10 . In addition, the user interface  101  accepts a request for originating a call from the user. As described below, a request for originating a call except for an emergency call is rejected during the self mode. 
     The control unit  103  controls processing in the radio (the transmitter  107  and the receiver  105 ) in the mobile station and controls processing in the user interface  101 . The control unit  103  rejects transmission of radio waves (except for an emergency call) from the transmitter  107  and allows reception of a radio wave by the receiver  105  according to the setting request for establishing the self mode accepted by the user interface  101 . The control unit  103  also allows transmission of a radio wave from the transmitter  107  according to the release request for releasing the self mode accepted by the user interface  101 . For example, the control unit  103  may retain the setting status of the self mode as an ON state according to the setting request for establishing the self mode and deactivate the user interface associated with originating a call (except for an emergency call). At this moment, the control unit  103  may disable the transmitter  107 . The control unit  103  may also retain the setting status of the self mode as an OFF state according to the release request for releasing the self mode and activate the user interface associated with originating a call. At this moment, the control unit  103  may enable the transmitter  107 . 
     During the self mode, the control unit  103  rejects transmission of a radio wave (except for an emergency call) from the transmitter  107 . When the user interface  101  accepts a request for originating an emergency call during the self mode, the control unit  103  allows transmission of the emergency call. For example, whether the requested call is an emergency call may be determined based on whether the telephone number of the requested call matches one of emergency telephone numbers which are registered in advance in the mobile station  10 . 
     During the self mode, the control unit  103  also allows reception of a radio wave by the receiver  105 . Accordingly, even during the self mode, the receiver  105  can receive information necessary for a carrier search or a cell reselection and the control unit  103  can perform the carrier search or the cell reselection. In addition, even during the self mode, the receiver  105  can receive a paging message and the control unit  103  can determine from the paging message whether the paging message is for an emergency incoming call. During the self mode, the control unit  103  rejects an incoming call (except for an emergency incoming call) without responding to the incoming call. When the receiver  105  receives an emergency incoming call during the self mode, the control unit  103  accepts the emergency incoming call and responds to the incoming call. For example, whether the incoming call is an emergency incoming call may be determined based on whether a predetermined information element in the paging message indicates an emergency. As described above, the emergency incoming call includes an emergency message such as ETWS or CBS and an incoming call requiring emergency attention from a police station, a fire department, or the like. In addition, the control unit  103  may allows reception of a broadcast service such as CBS (cell broadcast service) or MBMS (multimedia broadcast and multicast service) during the self mode. 
     When the location registration area is changed due to movements of the mobile station  10  during the self mode, or when a location registration needs to be performed at a predetermined time interval, the control unit  103  defers the location registration, so that transmission of a radio wave associated with the location registration can be rejected. When the self mode is released, the control unit  103  performs the deferred location registration. 
     In addition, the control unit  103  may lengthen a DRX (discontinuous reception) period during the self mode. For example, upon accepting the setting request for establishing the self mode, the control unit  103  may request, via the transmitter  107 , a longer DRX period over the network (for example, to the base station). The controller  103  receives a paging message during the self mode according to a DRX period provided from the network in response to the request. 
     The receiver  105  receives information provided from the network. Since the receiver  105  is enabled during the self mode, the receiver  105  can receive information necessary for a carrier search or a cell reselection, broadcast information, and a paging message. For example, the receiver  105  may receive an emergency paging message. For example, the receiver  105  may receive a paging message for modifying broadcast information, and then receive the broadcast information again. For example, when the mobile station  10  periodically verifies whether broadcast information is modified, the receiver  105  may periodically determine whether broadcast information is modified. 
     The transmitter  107  transmits information (data, voice, control information, etc.) from the mobile station over the network. For example, when the transmitter  107  is disabled during the self mode but the control unit  103  determines that an emergency call is to be originated, the transmitter  107  is enabled to originate the emergency call over the network. As described above, since the receiver  105  can receive information necessary for a carrier search or a cell reselection and broadcast information even during the self mode, the transmitter  107  can promptly originate the emergency call. 
     &lt;Procedure of Placing the Mobile Station in the Self Mode&gt; 
       FIG. 2  shows a sequence diagram of a procedure of placing the mobile station  10  in the self mode. While the sequence diagram shown in  FIG. 2  is described using the components in the mobile station  10  shown in  FIG. 1 , each step of the procedure of placing the mobile station in the self mode may be performed by other components. In addition, the sequence diagram shown in  FIG. 2  may be performed in different order. 
     When the user inputs a setting request for setting the self mode via the user interface  101  (S 101 ), the control unit  103  in the mobile station retains the setting status of the self mode as the ON state (S 104 ). At this moment, the control unit  103  may disable the transmitter  107  (S 105 ). In addition, the control unit  103  deactivates the user interface associated with originating a call (except for an emergency call) (S 107 ). The control unit  103  provides a setting response for establishing the self mode via the user interface  101  to the user, indicating that establishment of the self mode has been completed (S 109 ). According to these steps, the mobile station  10  is placed in the self mode. Upon accepting the setting request for establishing the self mode (S 101 ), the control unit  103  may request a longer DRX period over the network (for example, to the base station) before disabling the transmitter  107  (S 102 ). In response to this request, the control unit  103  receives a DRX period over the network and sets the DRX period (S 103 ). 
     The procedure in the mobile station  10  during the self mode will be described below with reference to  FIG. 3 . 
     When the user inputs a release request for releasing the self mode via the user interface  101  (S 111 ), the control unit  103  in the mobile station retains the setting status of the self mode as the OFF state (S 113 ). When the transmitter  107  is disabled during the self mode, the control unit  103  enables the transmitter  107  (S 115 ). In addition, the control unit  103  activates the user interface associated with originating a call (S 117 ). The control unit  103  provides a release response for releasing the self mode via the user interface  101  to the user, indicating that release of the self mode has been completed (S 119 ). According to these steps, the self mode is released and the mobile station  10  is placed in the normal operating mode. 
     When a location registration is deferred during the self mode (S 121 ), the control unit  103  performs the deferred location registration (S 123 ). 
     &lt;Procedure of Originating an Emergency Call and Receiving an Emergency Incoming Call in the Mobile Station&gt; 
       FIG. 3  shows a procedure of originating an emergency call and receiving an emergency incoming call in the mobile station  10 . While the sequence diagram shown in  FIG. 3  is described using the components in the mobile station  10  shown in  FIG. 1 , each step of the procedure may be performed by other components. In addition, the sequence diagram shown in  FIG. 3  may be performed in different order. 
     First, the mobile station  10  is placed in the self mode according to the procedure shown in  FIG. 2 . During the self mode, the mobile station  10  receives broadcast information by the receiver  105  (S 201 ). In addition, the mobile station  10  may receive may receive a message for modifying broadcast information by the receiver  105  (S 203 ), and then receive the broadcast information again (S 205 ). During the self mode, the mobile station  10  may perform a carrier search or a cell reselection by detecting a predetermined signal sequence. It should be noted that the carrier search or the cell reselection is performed as needed outside the communication area or when the reception level is low, and that reception or second reception of the broadcast information is performed as needed after the carrier search or the cell reselection or at a predetermined time interval. During the self mode, the mobile station  10  may also receive a broadcast service such as CBS or MBMS. 
     During the self mode, when the user inputs a request for originating a call via the user interface  101  (S 211 ), the control unit determines whether the requested call is an emergency call. For example, whether the requested call is an emergency call may be determined based on whether the telephone number of the requested call matches one of emergency telephone numbers which are registered in advance in the mobile station  10 . When the requested call is not an emergency call, the control unit  103  rejects transmission of the call because of being in the self mode (S 213 ). 
     During the self mode, when the user inputs a request for originating an emergency call via the user interface  101  (S 221 ), the control unit determines whether the requested call is an emergency call. When the requested call is an emergency call, the control unit  103  allows transmission of the emergency call regardless of the self mode (S 223 ). 
     During the self mode, when the mobile station  10  receives a paging message for an incoming call (S 231 ), the control unit  103  determines whether the incoming call is an emergency incoming call. When the incoming call is an emergency incoming call, the control unit  103  accepts the emergency incoming call (S 233 ). For example, whether the incoming call is an emergency incoming call may be determined based on whether a predetermined information element in the paging message indicates an emergency. The control unit  103  responds to the emergency incoming call and processes the paging message received by the receiver  105  (S 235 ). For example the control unit  105  may display information about the emergency message on the user interface  101  or may initiate a ring tone in response to the incoming call requiring emergency attention. 
     During the self mode, when the mobile station  10  receives a paging message for an incoming call (S 241 ), the control unit  103  determines whether the incoming call is an emergency incoming call. When the incoming call is not an emergency incoming call, that is, when the incoming call is a normal incoming call, the control unit  103  rejects the incoming call without responding to the incoming call (S 243 ). 
     When the location registration area is changed due to movements of the mobile station  10  during the self mode, or when a location registration needs to be performed at a predetermined time interval (S 251 ), the control unit  103  defers the location registration (S 253 ). 
     &lt;Example of a Paging Message&gt; 
       FIG. 4  shows an example of a paging message used in an embodiment of the present invention. As described above, during the self mode, the mobile station  10  receives a paging message and determines whether the paging message is for an emergency incoming call. For this reason, an information element indicating an emergency is included in the paging message. 
     In an LTE (Long Term Evolution) system, the configuration of a paging message shown in  FIG. 4(A)  is defined in TS 36.331 v840. The descriptions of information elements in the paging message are shown in Table 1. 
     
       
         
           
               
             
               
                 TABLE 1 
               
             
            
               
                   
               
               
                 Descriptions of information elements 
               
               
                 in paging message for LTE system 
               
            
           
           
               
               
               
            
               
                   
                 Information element 
                 Description 
               
               
                   
                   
               
               
                   
                 pagingRecordList 
                 Plural IDs for identifying 
               
               
                   
                   
                 destinations of incoming calls 
               
               
                   
                   
                 are included. 
               
               
                   
                 systemInfoModification 
                 This information element 
               
               
                   
                   
                 indicates whether broadcast 
               
               
                   
                   
                 information is modified. 
               
               
                   
                 Etws-Indication 
                 This information element is 
               
               
                   
                   
                 set when ETWS is provided. 
               
               
                   
                 nonCriticalExtension 
                 This information element is an 
               
               
                   
                   
                 extensible information element 
               
               
                   
                   
                 to maintain backward 
               
               
                   
                   
                 compatibility. When a new 
               
               
                   
                   
                 information element is added 
               
               
                   
                   
                 in the future, the new 
               
               
                   
                   
                 information element is added 
               
               
                   
                   
                 below this information 
               
               
                   
                   
                 element. 
               
               
                   
                 pagingcause 
                 This information element is 
               
               
                   
                   
                 added to indicate whether the 
               
               
                   
                   
                 paging message is for an 
               
               
                   
                   
                 emergency incoming call. In 
               
               
                   
                   
                 the case of an emergency 
               
               
                   
                   
                 incoming call, this 
               
               
                   
                   
                 information element is set to 
               
               
                   
                   
                 an emergency. 
               
               
                   
                   
               
            
           
         
       
     
     For example, as shown in  FIG. 4(B) , in order to set an information element indicating whether the paging message is for an emergency, an information element called “paging cause” may be included in the paging message. The information element “paging cause” may be added below the information element called “nonCriticalExtension”. In the case of an emergency incoming call, the information element “paging cause” may be set to an emergency. 
     By verifying a predetermined information element in the paging message in this manner, the mobile station  10  can determine whether the paging message is for an emergency incoming call. In a UMTS (Universal Mobile Telecommunications System), an information element indicating an emergency can be similarly included in the paging message. The present invention is not limited to an LTE system and a UMTS system, but is also applicable to any communication system using an emergency call (emergency outgoing call) and emergency incoming call. 
     According to an embodiment of the present invention, since the receiver  105  receives information necessary for a carrier search or a cell reselection and broadcast information even during the self mode, the mobile station  10  can shorten the time to originate an emergency call. 
     In addition, since the receiver  105  can receive a paging message even during the self mode, the control unit  103  can verify a predetermined information element in the paging message and receive an emergency message such as ETWS or CBS and an emergency incoming call such as an incoming call from a police station, a fire department, or the like. 
     In addition, even during the self mode, the receiver  105  can receive a message for modifying broadcast information and receive the broadcast information again. 
     In addition, since the control unit  103  defers a location registration during the self mode, transmission of a radio wave from the transmitter  107  can be avoided. When the self mode is released, the location registration is performed and then the mobile station  10  can continue normal operations. 
     In addition, since the control unit  103  lengthens a DRX period during the self mode, power consumption can be reduced. 
     The present international application claims priority from Japanese Patent Application No. 2009-089513 filed on Apr. 1, 2009, the entire contents of which are hereby incorporated herein by reference. 
     DESCRIPTION OF NOTATIONS 
     
         
         
           
               10  mobile station 
               101  user interface 
               103  control unit 
               105  receiver 
               107  transmitter