Abstract:
A method of identifying an emergency call received on a mobile device includes receiving a call from an emergency call center. In association with the call, an emergency signal is received, indicating that the call is an emergency call. Information is displayed on the mobile device to identify the emergency call.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This is a continuation of U.S. patent application Ser. No. 11/591,230, filed Nov. 1, 2006 now U.S. Pat. No. 7,412,225, which is a continuation of U.S. patent application Ser. No. 11/350,219, filed Feb. 8, 2006 (now U.S. Pat. No. 7,139,549), which is a continuation of U.S. patent application Ser. No. 10/730,144, filed Dec. 8, 2003 (now U.S. Pat. No. 7,050,785), all three applications hereby incorporated herein by reference. 
    
    
     TECHNICAL FIELD 
     This application relates to emergency calls communicated on a mobile communication device. 
     BACKGROUND 
     When a mobile station places an emergency call, the network typically routes the call to an emergency call centre such as Public Safety Answering Point (PSAP). When the emergency call ends, the MS typically stays in an emergency callback mode for at least the duration of time known as the emergency callback period. During this time, the Emergency Call Centre may attempt to callback the MS. 
     Mobile stations that subscribe to caller id may attempt to determine that an incoming call is a callback from an emergency call centre by screening the caller id of incoming calls. However, this may not work if the caller id is not recognized as belonging to an emergency call centre. Furthermore, this will not work if the user of the mobile station has not subscribed to the caller id service, or even having subscribed to the caller id service, if a caller invokes caller id restriction when placing a call to the user during the emergency callback period. In addition, if the user does not subscribe to the call-waiting feature, this may prevent the emergency call centre from reaching the user if the user decides to take a non-emergency voice call. This could also happen at any time outside of emergency callback period. 
     Consequently, there is a need for a standard mechanism on mobile stations to adequately differentiate between an incoming call from an Emergency Call Centre, and an incoming non-emergency call. 
     SUMMARY 
     According to one aspect of the present application, there is provided a method of explicitly indicating that a mobile station terminated call is from an emergency call centre, the method comprising the steps of: forming an emergency signal in relation to the mobile station terminated call; sending said emergency signal to the mobile station on behalf of the emergency call centre; and detecting said emergency signal at the mobile station. 
     According to another aspect of the present application, there is provided an apparatus for explicitly indicating that a mobile station terminated call is from an emergency call centre, the apparatus comprising: emergency signal forming means for forming an emergency signal in relation to the mobile station terminated call; emergency signal sending means for sending said emergency signal to the mobile station on behalf of the emergency call centre; and emergency signal detecting means for detecting said emergency signal at the mobile station. 
     Other aspects and features of the present application will become apparent to those ordinarily skilled in the art upon review of the following description of specific embodiments of an apparatus and method of explicit indication of call from emergency call centre in conjunction with the accompanying figures. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Embodiments of the present application will now be described, by way of example only, with reference to the attached figures, wherein: 
         FIG. 1  is a block diagram illustrating a mobile station in one embodiment of the apparatus and method of the current application; 
         FIG. 2  is a block diagram illustrating in greater detail the apparently continuous emergency call aspect provided in accordance with one embodiment of the apparatus and method of the current application; 
         FIG. 3  is a block diagram illustrating in greater detail the location privacy aspect provided in accordance with one embodiment of the apparatus and method of the current application; and 
         FIG. 4  is a block diagram illustrating in greater detail the emergency notification aspect provided in accordance with one embodiment of the apparatus and method of the current application. 
     
    
    
     Same reference numerals are used in different figures to denote similar elements. 
     DESCRIPTION 
     Referring to  FIG. 1 ,  FIG. 1  is a block diagram illustrating a mobile station in one embodiment of the apparatus and method of the current application. When a mobile station  10  places an emergency call  20 , the wireless network  30  typically routes the call to an emergency call centre  40  such as a Public Safety Answering Point (PSAP). After the emergency call  20  ends, due to normal termination or fading, the mobile station  10  typically stays in emergency callback mode  35  for a certain duration. The idea is to stay on the system so that emergency call centre  40  can call the subscriber  80  back if necessary. 
     Advantageuosly, by providing a new emergency signal  60  in accordance with the apparatus and method of the present application,  FIG. 1  shows that mobile station  10  is enabled to adequately differentiate between an incoming non-emergency call  60  and an incoming call from emergency call centre  40 , such as emergency callback  70 . 
     Further advantageously, mobile station  10  is enabled to block any non-emergency calls destined to the mobile station  10 , such as but not limited to non-emergency call  50 , while mobile station  10  is in emergency callback mode  35 . 
     Yet further advantageously, subscriber  80  operating mobile station  10  has not had to rely on caller id in order to determine that an incoming call, such as one of call  50  and call  70 , is from an emergency call centre  40 , and this even if caller  90  invokes caller id restriction when placing call  50  to the subscriber  80 . 
     Yet further still advantageously, even if subscriber  80  did not subscribe to a call-waiting feature for mobile station  10 , emergency call centre  40  is systematically enabled to callback mobile station  10 . Stated otherwise, in the absence of emergency signal  60  provided in accordance with the apparatus and method of the present application, the lack of call-waiting may traditionally prevent emergency call centre  40  from reaching the subscriber  80  if the subscriber decides to take a non-emergency voice call. 
     These advantages can work together to enable an apparently continuous emergency call  100  whereby mobile station originated emergency call  20 , mobile station terminated emergency call  70 , and any subsequent mobile station terminated emergency calls thereto can be made to appear to subscriber  80  as though one continuous emergency call  100  results from mobile originated emergency call  20 , and this independent of fade-outs, non-emergency call attempts, such as  50 , to reach the mobile station  10 , the presence or absence of call waiting functionality at the mobile station  10 , and the presence or absence of caller id functionality at the mobile station  10 . This is analagous to how a “911” call is handled on fixed line circuit switched phone call, i.e. the circuit remains “open” to provide a life line to the caller. 
     Turning now to  FIG. 2 ,  FIG. 2  is a block diagram illustrating in greater detail the apparently continuous emergency call aspect provided in accordance with one embodiment of the apparatus and method of the current application. During emergency calls  210 , such as emergency call  20  and emergency callback  70  of  FIG. 1 , mobile station  10  maintains an emergency callback timer  220  controlled by emergency continuity controller  230 . Emergency continuity controller monitors the start of all calls  240 , the end of all calls  250 , as well as detecting emergency signal  60 , to ensure that if subscriber  80  sets emergency options  230  to appear continuous, regardless of how many mobile originated or mobile terminated calls occur in emergency calls  210 , these substantially appear as a single continuous emergency call  100  to subscriber  80 . 
     Operationally, when subscriber  80  makes an emergency call, such as emergency call  20  of  FIG. 1 , emergency continuity controller  220  monitors the start call start  240 , determines that an emergency call has been requested, and prepares to monitor the call end  250 . When the emergency call ends, emergency continuity controller  230  starts emergency callback timer  220 , which places the mobile station  10  in emergency callback mode  35 . 
     When an incoming call arrives, emergency continuity controller  230  determines if emergency signal  60  was detected to indicate that the incoming call, such as emergency callback  70 , was from emergency call centre  40 . If so determined, emergency continuity controller examines the emergency options  230  to determine if the emergency calls  210  should appear continuous. If so determined, emergency continuity controller  230  handles call set up on behalf of subscriber  80 , for example by answering the call automatically if subscriber  80  does not answer within certain time and/or by enabling speakerphone capability if mobile station  10  is so equipped. Emergency continuity controller  230  may additionally determine if the emergency callback mode  35  is still active, and if so, resets the emergency callback timer  220  once the incoming emergency call starts. 
     Conversely, if emergency signal  60  was not detected, emergency continuity controller can rely on other traditional techniques such as caller id and call waiting to assist subscriber  80 , or block the incoming call to ensure that emergency call centre  40  is able to reach subscriber  80  for at least the duration of emergency callback timer  220 . 
     Given the ability to make one or more emergency calls  210  substantially appear as one continuous emergency call, it is envisaged to be within the scope of the present application to have a mobile station deliberately terminate either of the mobile originated or mobile terminated emergency calls. In one CDMA embodiment, since some CDMA frequencies can interfere with GPS frequencies, it is envisaged that the mobile station deliberately terminates an emergency call so as to turn its CDMA transmitter off to make accurate GPS measurements for emergency location services. Once the GPS measurements have been taken the mobile station turns it&#39;s CDMA transmitter back on and awaits to detect an emergency signal from the emergency call centre, or originates a new call to the emergency call centre to provide location information and benefit from location based services. Since it is the mobile station which is performing these acts on behalf of the subscriber, it appears to the subscriber as if one continuous emergency call is in progress. 
     It is also envisaged to be within the scope of the present application to have the emergency call centre or wireless network deliberately discontinue either of the mobile originated or mobile terminated emergency calls. In one exemplary embodiment for example, it is envisaged that the emergency call centre deliberately drop the emergency call in order to enable first responders, such as the fire department, police, or ambulance, to be able to reach the mobile station and communicate with the subscriber. 
     It is also further envisaged to combine both of these deliberate termination of emergency calls so as to first enable the mobile station to determine it&#39;s location, to provide the mobile station location to the emergency call centre, and then enable the emergency call centre to hand the mobile station off to a first responder which is nearest to the determined location of the mobile station, all the while maintaining the appearance of a single emergency call to the mobile station subscriber. 
     Turning now to  FIG. 3 ,  FIG. 3  is a block diagram illustrating in greater detail the location privacy aspect provided in accordance with one embodiment of the apparatus and method of the current application. In  FIG. 3 , the presence of an explicit indication that the call is indeed from an emergency call centre, such as the presence of emergency signal  60 , can advantageously enable the resolution of privacy issues associated with location services  320 . For example, the subscriber  80  can decide to allow location services  220  if he/she gets a call  370  from emergency call centre  40  outside of emergency callback period. In the exemplary embodiment shown in  FIG. 3 , if the emergency callback timer  220  expires, then the locator  340  that provides location services  320  is disabled. An example locator is a GPS measurement device, which makes measurements of GPS signals and conveys these measurements to the wireless network to process and send back location information. In  FIG. 3 , mobile station  10  is not currently operating in emergency callback mode when location privacy controller  360  detects emergency signal  60 . If location service options  350  configure location privacy controller  360  to allow location services outside emergency callback mode, then locator  340  and location services  320  are enabled. Conversely, if location privacy controller  360  is configured not to allow location services outside emergency callback mode, then also advantageously locator  340  and location services  320  are disabled. Regardless of location service options, location privacy controller  360  preferably enforces any requirements mandated by law, such as for example ensuring locator  340  and location services  320  are enabled during emergency callback mode, if so required. This is illustrated in greater detail in  FIG. 4 . 
     Turning to  FIG. 4 ,  FIG. 4  is a block diagram illustrating in greater detail the emergency notification aspect provided in accordance with one embodiment of the apparatus and method of the current application. The detection of an emergency signal can improve emergency roaming conditions when the subscriber may not even understand the language of local emergency call centre service, but may still want to allow location services  320  if there is an explicit language-independent indication from the network. 
     Referring to  FIG. 4 , the subscriber  80  can decide to allow location services  320 , such as GPS location services, if he/she gets a call  370  from the emergency call centre  40  outside of emergency callback period so long as that call includes emergency signal  60 . Emergency notification controller  410  determines if there is an explicit network indication that the call is indeed from emergency call centre  40 . If so determined, emergency notification controller  410 , depending on notification options  420 , can decide to allow location services  320  if mobile station  10  gets a call from emergency call centre outside of emergency callback period. Advantageously, notification options  420  include the preferred locale of subscriber  80 , so that emergency notification controller  410  localizes localizable emergency information  430  to provide useable emergency information  440  to subscriber  80 . 
     The precise nature of the emergency information  440  may further depend on the notification options  420  as configured through emergency operation  450  by subscriber  80 , either prior to or during emergency calls. Emergency information  440  is preferably adapted to the preferred locale of the subscriber  80  so that when subscriber  80  observes emergency information  440  it is in a form that is readily understood. 
     For example, consider a subscriber  80  who&#39;s preferred locale is “English (U.S.)”, as illustrated in notification options  420 . Regardless of where subscriber  80  is roaming with his mobile station  10 , localized emergency information that is readily understood by the subscriber, such as the “English (U.S.)” localized message “Emergency Call”, is observed in emergency information  440 . Another subscriber who&#39;s preferred locale is “Français” would observe a message such as “Appel d&#39;urgence”, while yet another subscriber who&#39;s preferred locale is “Español” would observe a message such as “Llamad de emergencia”. 
     One of many mechanisms that can be used at the mobile station  10  to accomplish this is to use tables to store the various localized emergency information, and then use the locale to look up the localized emergency information within the tables. To continue with the example “Emergency Call” message above, a table EMERGENCY_CALL could be provided in localizable emergency information  430 . EMERGENCY_CALL could include the following emergency information messages {“Emergency Call”, “Emergency Call”, “Emergency Call”, “Emergency Call”, “Appel d&#39;urgence”, “Llamada de emergencia”, “Chiamata di emergenza”, “Notruf”} each of which corresponds to the following locales {“English (U.S.)”, “English”, “English (United Kingdom)”, “English (Nederland)”, “Français”, “Español”, “Italiano”, “Dutch”}. 
     Although not expressly shown in  FIG. 4 , instead of indicating a single preferred locale in notification options  420 , it is envisaged that subscriber  80  may want to rank them in order of preference. Thus, using the list of locales as an example of a preferred ranking, if emergency notification controller  410  cannot find localizable emergency information  440  corresponding to the preferred locale of the subscriber  80 , emergency notification controller proceeds to attempt to find localizable emergency information  440  for each of the next preferred locales in order, i.e. it tries “English (U.S.)”, “English”, “English (United Kingdom)”, “English (Nederland)”, “Français”, “Español”, “Italiano”, and finally “Dutch”. If no localizable emergency information can be located after exhausting the preferred ranking of locales, pre-programmed default emergency information is used. 
     Although not expressly shown in the drawings, it is contemplated that localizable emergency information may further depend on the nature of the emergency. For example, if emergency signal  60  carries an emergency code to qualify the nature of the emergency, then emergency notification controller  410  advantageously provides localized emergency information to enable subscriber  80  to better cope with the nature of the specific emergency. The emergency call centre could have, for example, determined the emergency signal code corresponding to the nature of the emergency, and may even update the code during the emergency call or callback. Thus, the specific emergency information observed by a subscriber who has just experienced a car collision could be different than the specific emergency information observed by a subscriber who is attempting to deliver a baby. 
     Although messages were used in the above example for localizable emergency information, localizable non-textual emergency information may also be included in localizable emergency information  430 . The types of emergency information  440  which may be observed by subscriber  80  include, but is not limited to, text, audio, audible signals, icons, graphics, pictures, pictograms, guidelines, instructions or just about any other type of information which may be helpful in assisting the subscriber during the emergency. 
     One mechanism which could accomplish this flexibility would be to provide a list of localizable URLs so that the mobile station could fetch the various types of emergency information using a highly standardized emergency browser. These URLs could either be stored locally in the mobile station, or preferably be updated automatically, either prior to or during an emergency call. In the latter case, the URLs could, for example, be included along with the above mentioned emergency code in the emergency signal. 
     Furthermore, to enforce the apparent continuity of emergency services, it is envisaged that some notifications remain observable throughout multiple emergency calls. For example, the message “Emergency Call” may be continually displayed transparently over the visual interface, while an audible repetitive “Beep” may be heard. The specific type of notification may also further be limited depending on the nature of the emergency. For instance, it may be detrimental to the subscriber if the repetitive “Beep” is heard if the nature of the emergency requires the subscriber to remain silent. As another example, instead of talking to the subscriber, the nature of the emergency may suggest that the emergency centre use short messaging service instead of a voice call to communicate emergency information to the subscriber. 
     Thus subscriber  80  is thus enabled to receive emergency services under roaming conditions even when the user may not understand the language of local emergency call centre service, but may still allow location services if there is an explicit language-independent indication from the network. 
     Returning now to the concept of the emergency signal, any explicit indication that is conveyed to the subscriber of a mobile station for mobile station terminated calls from an emergency centre is a valid alternative. With such a mechanism provided, in view of the present application, then the subscriber will be able to make better decisions whether to take an incoming call or not when he/she is expecting a call from the emergency centre. This concept can be applied to a first incoming call as well as any call-waiting call. 
     In case of a cdma2000 standards based embodiment, an explicit indication, i.e. an emergency signal, can be provided as follows. Define a new information record to indicate global emergency callback, similar to current Global Emergency Call Record defined in ballot version of IS-2000 release D for mobile-originated calls. The network includes this new record when it sends “Alert/Flash with Info” (AWI/FWI) message to alert the user of incoming call from emergency call centre. If the subscriber does not have call-waiting, then he/she can decide whether to take a call during emergency callback period or anytime after that. The network includes this new record when it sends Flash with Info message to alert the user of incoming call-waiting call from an emergency call centre when the user is in call. This is applicable when the user has call-waiting feature. 
     The details of a specific exemplary cdma2000 standard embodiment are made clearer by considering some changes that could be made to the cdma2000 standard in order to support the techniques of this application. First, consider the proposed change to Table 3.7.5-1: 
                                                       Proposed Information Record                Record                       Information   Type   Message           P_REV_IN       Record   (binary)   Type   f-csch   f-dsch   _USE 1                 Global   00010111   AWI   N   Y   ≧11       Emergency       FWI   N   Y       Call                    
Next, consider the addition of paragraph 3.7.5.24:
 
     3.7.5.24 Global Emergency Call
         This information record allows the network to inform the mobile station that a call is an emergency callback call from the PSAP   This information record includes no type-specific fields.       

     The above-described embodiments of the present application are intended to be examples only. Those of skill in the art may effect alterations, modifications and variations to the particular embodiments without departing from the scope of the application.