Abstract:
A system, method, and computer readable medium comprising instructions for providing temporary callback number for emergency calls is disclosed. A determination is made as to whether a restriction is imposed on a mobile user for incoming calls. A temporary callback number for the mobile user is generated if the restriction is imposed. A request for a callback to the mobile user comprising the temporary callback number is detected. The callback is routed to the mobile user using the temporary callback number.

Description:
FIELD OF THE INVENTION 
       [0001]    The present disclosure is generally related to an emergency service communications network, and more particularly to providing temporary callback numbers for calls to emergency services in an emergency service communications network. 
       BACKGROUND OF THE INVENTION 
       [0002]    In an emergency situation, persons involved or bystanders often contact emergency services by placing a 9-1-1 emergency call from their home or cellular phone. An emergency operator at a public safety answering point (PSAP) who received the call takes the information provided by the caller and may initiate or coordinate the dispatching of the necessary emergency service providers to handle the situation. Common emergency service providers that are dispatched include the police, the fire department, emergency medical services (EMS), and the like. 
         [0003]    However, some callers may have call restrictions placed on their phones or their phones have an address or phone number that cannot be dialed over the PSTN or represented as a ten-digit North American numbering plan number. For example, a phone may be restricted as to what numbers it may call and who can call that phone. A child&#39;s phone may be setup so that the child can only call 911 or the parents and can only receive calls from the phone numbers associated with the parents. Calls and text messages to and from other phone numbers may be blocked. While these features may be advantageous to some callers, a problem exists when emergency calls are placed and a callback is initiated by emergency service providers. Because the phone number of an emergency service provider is not an “allowed number”, an incoming call from the emergency service provider may be blocked. Therefore, what is needed is the ability to provide a method to call back these restricted phones by use of a temporary call back number. 
       SUMMARY OF THE INVENTION 
       [0004]    The present disclosure provides a method, a system, and computer instructions for providing temporary callback number for emergency calls in an emergency service communications network. 
         [0005]    The present disclosure describes a method for providing temporary callback numbers for emergency calls. A determination is made as to whether a restriction is imposed on a mobile user for incoming calls or for some other reason the PSAP may have difficulties returning a call to this caller with the native address of the device. A temporary callback number for the caller is allocated if the system determines there may be difficulties in successfully returning the call to the caller. If a callback using the temporary callback number is attempted, the call will be routed to a gateway where it will be relayed to the true address or phone number of the caller. If the caller is restricted from receiving specific calls, the system will allow the call through because of special pre-determined identifiers such as a special value for the ANI (Automatic number identification) or the Calling Party Number 
         [0006]    The present disclosure describes a system for providing temporary callback numbers for emergency calls. The system comprises a mobile unit, a mobile switching center (MSC) communicably coupled to the mobile unit and the emergency call voice network, a gateway mobile location center (GMLC) or Mobile Positioning Center (MPC) for determining the routing of an emergency call. The GMLC or MPC is communicably coupled to the mobile switching center (MSC) and emergency service data network, a temporary callback number gateway which is communicably coupled to the GMLC/MPC and a telephone network, and a public safety answering point for initiating a callback to the mobile unit through the telephone network, the public safety answering point is communicably coupled to the emergency call voice network and the emergency call data network. The system further comprises a database for storing user information of the mobile unit, the database is communicably coupled to the GMLC/MPC. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0007]      FIG. 1  depicts an exemplary emergency service communications network; 
           [0008]      FIG. 2  depicts a system for providing temporary callback numbers for emergency calls to emergency service providers in accordance with one embodiment of the present disclosure; 
           [0009]      FIG. 3  depicts a diagram illustrating call flows for providing temporary callback numbers for emergency calls in accordance with one embodiment of the present disclosure; 
           [0010]      FIG. 4  depicts a flowchart of a process for providing a temporary callback number for emergency calls in accordance with one embodiment of the present disclosure; and 
           [0011]      FIG. 5  depicts a flowchart of a process for routing a callback from the PSAP to a caller. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0012]    Referring now to  FIG. 1 , an exemplary emergency service communications network is depicted. In emergency service communications network  100 , a caller  102  places an emergency call, for example, by dialing 9-1-1, using a wired telephone  104 . Central office  106 , which is connected to telephone  104 , recognizes from the dialed number that this call requires emergency treatment. Central office  106  then seizes a trunk  108  to selective router  110  and transmits the telephone number (TN) of telephone  104  to selective router  110 . Telephone number (TN) uniquely identifies telephone  104  in emergency service communications network  100  and may be used interchangeably with directory number (DN) as an automatic number identification when the directory number is sent from one network component to another. 
         [0013]    Once selective router  110  receives the call with the telephone number (TN), it selects the appropriate PSAP  114 , based upon the TN, and forwards the call to that Public Safety Answering Point (PSAP). When PSAP  114  receives the call from telephone  104 , it queries the Automatic Location Identification  112  with the TN that it received from the selective router  110 . The ALI  112  then performs a database lookup using the TN as a key and retrieves records associated with the TN. Examples of records retrieved include caller&#39;s location information, such as, a street address, geo-location coordinates, and the like. ALI  112  then forwards these records to PSAP  114  for its use in providing proper emergency response. 
         [0014]    In addition to a wired telephone call, caller  102  may place an emergency call using a cellular phone  118 . Cellular phone  118  transmits the call to a cellular tower  120 , which forwards the call to a mobile switching center (MSC)  122  within a mobile communications network  124 . In some embodiments, subscribers may place voice calls, transmit/receive data, and/or send short messages from their respective cellular phones. In addition to cellular phone  118 , caller  102  may place emergency call or other calls via other devices, such as Voice over Internet Protocol (IP) devise or other devices that do not have a traditional telephone number. An example is an international caller who is calling from a 13-digit phone number. 
         [0015]    The mobile switching center (MSC)  122  receives the call and contacts a mobile positioning center (MPC) or Gateway Mobile Location Center (GMLC)  126  to obtain routing instruction on how to route the call. The MPC may query the Position Determining Entity (PDE) or Serving Mobile Location Center (SMLC)  128  in order to establish a geographical area for routing the call to an appropriate PSAP. 
         [0016]    Once the location is determined, MPC/GMLC  126  returns an emergency service routing key (ESRK) to the MSC  122 . This ESRK will ultimately be used by the PSAP  114  to identify the emergency call. This ERSK will also be used by the MSC  122  to route the call to the appropriate selective router  110  and for the selective router  110  to route the call to the appropriate PSAP  114 . MSC  122  then sends the call identified by the ESRK to selective router  110 . Selective router  110  determines the appropriate PSAP to route the call based upon the ESRK that it received. The selective router  110  routes the call to the appropriate PSAP and passes along the ESRK with the call. 
         [0017]    Similar to the wired call, PSAP  114  uses the ESRK of cellular phone  118  as a key to query ALI  112  for records associated with cellular phone  118 . ALI  112  forwards the ESRK to MPC/GMLC  126 , which returns the cached caller information which typically includes information such as the caller&#39;s carrier, their PSTN phone number and their location. This information is returned to the PSAP  114  for its use in providing proper emergency response. 
         [0018]    Cellular phone  118 , however, may have restrictions placed in it, which prevents calls and text messages to and from phone numbers that are not designated as “allowed numbers”. In that case, PSAP  114  may not be able to initiate a callback to cellular phone  118 , which significantly impacts the efficiency of emergency services provided by PSAP  114 . Aspect of the present disclosure provides a system for providing temporary callback numbers to PSAPs, such that callbacks may be initiated without being blocked. 
         [0019]      FIG. 2  provides a system for providing temporary callback numbers for emergency calls to emergency service providers. Similar to system  100 , caller  202  may place a 9-1-1 emergency call using a cellular phone  204 . Cellular phone  204  transmits the call to a cellular tower  206 , which forwards the call to a mobile switching center (MSC)  208 . The MSC  208  queries the MPC/GMLC  210  for routing instructions. The MPC/GMLC  210  queries a database  216  to help determine if the subscriber needs to have a temporary callback number assigned. Database  116  may be a database of a mobile service provider comprising of all users, groups of users, classes of users or users that may have some form of a restriction. If the MPC/GMLC  210  determines that a temporary callback number needs to be assigned, because the current callback number can not be use to callback the caller, the MPC/GMLC  210  will assign a temporary callback number for this call and will store that number for later use. 
         [0020]    The MPC/GMLC  210  will then return the routing information to the MSC  208  so that it can route the call to the Emergency Services Voice network  224 . The Emergency Services Voice network  224  will route the call to the appropriate PSAP. The emergency services voice network  224  may be implemented as a Selective router  110  or similar device. Upon receiving the call, the PSAP  218  sends a query to MPC/GMLC  210 , through the Emergency Services Data network  234  for the callback number and location information of cellular phone  204 . In this example, the callback number has been replaced with the temporary callback number by the MPC/GMLC  210 . 
         [0021]    Upon receiving the temporary callback number and location information, the PSAP  218  stores the information for later use. After some time has passed, PSAP  218  initiates a call back to the cellular phone  204  over the telephone network  254  using the temporary callback number as the destination number. The telephone network  254  routes the call to the Temporary Callback Number Gateway  244 . The temporary callback number gateway  244  then sends a query to MPC/GMLC  210  for the actual callback number of cellular phone  204 . When GMLC  210  returns the actual callback number, the Temporary Callback Number Gateway  244  acts as an intermediary and routes the callback to MSC  208  over the PSTN or a dedicated network. The Temporary Callback Number Gateway  244  replaced the Calling Party Number of the incoming call from the PSAP  218  with a predetermined value known by the MSC that will allow the call to be delivered to the cellular phone  204 . Upon receiving the call, MSC  208  allows the call back to reach cellular phone  204  without being blocked. 
         [0022]    Referring to  FIG. 3 , a diagram illustrating call flows for providing temporary callback numbers for emergency calls is depicted in accordance with an embodiment of the present disclosure. All or some of the steps in  FIG. 3  may be implemented as computer instructions executing within one or more of the depicted modules. User equipment  302  dials an emergency 9-1-1 call  304 . MSC  306  detects the 9-1-1 emergency call  304  and launches an initial address message (IAM)  308  to GMLC  310 . In one exemplary implementation, IAM message  308  comprises multiple fields but only three relevant fields are shown: CdPN, CgPN, and GDP. CdPN may comprise a mobile station integrated service digital network (MSISDN) of user equipment  302 . MSISDN is a unique public telephone network identifier assigned to cellular phone  204  or equipment entity  302 . CdPN may comprise “911” or similar identifier indicating an emergency call. GPD may comprise an emergency service routing number (ESRN), which is a 10-digit number identifying the cell site the 9-1-1 call was initiated on. 
         [0023]    Upon receiving the IAM message  308 , GMLC  310  determines if restrictions are imposed on user equipment  302  which will block or redirect callbacks from the PSAP by initiating a query  312  to the User Info database  314 . The user info database  314  may be a local database, carrier database, Home Location Register or other similar database containing user information and call restrictions. The query  312  may contain the users MSISDN, IMSI or other unique identifying value that identifies user equipment  302 . The user info database  314  returns back any restrictions  316  that may be imposed upon the user equipment  302  which may prevent the PSAP from calling back the user equipment  302 . 
         [0024]    If restrictions are imposed on user entity  302  for incoming calls or the GMLC  310  believes that for some other reason the may not be able to call back the user equipment  302  or have enough information to call back the user equipment  302 , the GMLC  310  allocates a temporary callback number (TCBNUM) that will be used as a callback number to ultimately reach user equipment  302  for 9-1-1 emergency call  304 . The duration of TCBNUM may be predefined and last for a period of time, for example, several minutes, hours or days. Once the TCBNUM is allocated, GMLC  310  returns an IAM message  318  to MSC  306  to complete the loop around call. In one exemplary implementation, TAM message  318  comprises at least two fields: CdPN and CgPN, both of which comprise the emergency service routing key (ESRK). 
         [0025]    Based on the routing information provided by GMLC  310 , the MSC  306  routes the 9-1-1 emergency call to emergency services voice network  322  and eventually to the interconnected PSAP. In this example, the call may be routed by sending an TAM message  320  to the emergency services voice network  322 . In other embodiments of the present disclosure, other methods to route the call may be used such as MultiFrequency signaling and Voice over Internet Protocol. TAM message  320  comprises at least a CdPN and CgPN. CdPN comprises a “911” or other identifier indicating an emergency call. CgPN may comprises an ESRK identifying the PSAP to which the emergency call is routed and an identifier of the caller. In other embodiments of this invention, other identifiers of an emergency call may be used including but not limited to ESRD and MSISDN. Upon receiving the TAM message, emergency services data network  324  of PSAP sends a query to GMLC  310  for location and callback information of user equipment  302 . The query may be sent via an ESPOSREQ message  326  that contains at least the ESRK. 
         [0026]    Upon receiving the query, GMLC  310  returns the location and callback information of user equipment  302 . In this example, the temporary callback number will be returned in place of the actual callback number. The information may be enclosed in an esposreq message  328 . In this way, the PSAP will use the temporary callback number to initiate the callback instead of the actual callback number. In addition, the esposreq message  328  comprises location information of user equipment  302 . 
         [0027]    After the emergency call, the PSAP initiates a callback to user equipment  302 . The PSAP places a call to the temporary callback number through the PSTN or other dedicated network. The temporary callback number (TCBNUM) is one of the numbers in a pool of numbers hosted by the temporary callback number gateway  332 . The call is routed to temporary callback number gateway  332  over the PSTN or other dedicated network. 
         [0028]    After receiving the call  330 , temporary callback number gateway  332  sends a query  334  to GMLC  310  for the actual callback number of user equipment  302 . The query  334  comprises the temporary callback number assigned by GMLC  310 . GMLC  310  then identifies the corresponding actual callback number and returns the actual callback number to the temporary callback number gateway  332  in a cb_req message  336 . The actual callback number is the MSISDN or some other routable identifier that can be used to route to the user equipment  302 . In turn, temporary callback number gateway  332  tandems the call back to the user equipment  302  based upon the MSISDN or other routable identifier. The temporary callback number gateway  332  will replace the received Calling Party number information or similar information with some predetermined value that will inform the MSC to allow the call to be connected to the user equipment  302 . The callback  338  is routed to the MSC  306  over PSTN or other dedicated network. When MSC  306  receives the IAM message  338 , it allows the callback to reach user equipment  02  based on the unique pre-determined ANI enclosed in the calling party number. In this way, callbacks initiated from PSAP may reach the user equipment  302  without being blocked or redirected. 
         [0029]    Referring to  FIG. 4 , a flowchart of a process for providing a temporary callback number for emergency calls is depicted in accordance with an embodiment of the present disclosure. Process  400  may be but is not limited to be implemented as computer instructions executing within the gateway mobile location center (GMLC)  310 . In this example, process  400  begins at step  402  when the GMLC detects the initiation of a 9-1-1 from the MSC. Next, process  400  continues to step  404  to send a query for user information to the user information database. 
         [0030]    Process  400  then continues to step  406  to determine if a restriction is imposed on the user based on the user information. If a restriction is imposed, process  400  continues to step  408  to allocate a temporary callback number for the user which will replace the normal callback number in step  414 . Process  400  then continues to step  410  to return routing information to the MSC. If no restriction is imposed, process  400  continues to step  410 . 
         [0031]    Process  400  then continues to  412  where GMLC detects a query for callback and location information from the PSAP. This query is initiated as a result of a callback request from the PSAP. Process  400  then completes at step  414  to send the temporary callback number allocated for the user to the PSAP. 
         [0032]    Referring to  FIG. 5 , a flowchart of a process for routing a callback from the PSAP to a caller is depicted in accordance with an embodiment of the present disclosure. Process  500  may be but is not limited to be implemented as computer instructions executing within the temporary callback number gateway  244 . In this example, process  500  begins at step  502  where after some time the PSAP decides to initiate a callback to the caller. Once the callback call is initiated, process  500  then continues to step  504  to receive a callback request from 911 telephone network  254 . The callback request includes the temporary callback number allocated by GMLC. Process  500  then continues to step  506  to query the actual callback number from MPC/GMLC  210 . Once the actual callback number is obtained, process  500  continues to step  508  to replace the calling party number with a predetermined value that will inform the MSC to allow the call to be connected to the caller. 
         [0033]    Process  500  then completes at step  510  to route the callback to the MSC  306  over PSTN or other dedicated network, which then tandems the call to the MSC by using a unique identifier so that the MSC will allow the call through. Using the temporary callback number, the PSAP may reach the user without being blocked or redirected by the restriction imposed on the user. 
         [0034]    In summary, aspects of the present disclosure provide a method, system, and computer readable media comprising instructions for providing a temporary callback number for emergency calls. By allocating a temporary callback number in place of the actual callback number, emergency callbacks may be initiated by PSAP to user with call restrictions without being blocked or redirected. 
         [0035]    It is noted that the present disclosure is not limited to the application of wired or wireless calls or to emergency service use. For example, the caller may be using a Voice over IP device that does not have a phone number but a Session Initiation Protocol address such as john@smith.us. Instead of the SIP address, a temporary callback number may be assigned to the Voice over IP device for a later callback from the PSTN. 
         [0036]    The present disclosure may also be used by an international caller with a 13-digit phone number. Because the PSAP can only display ten digits, a temporary callback number may be assigned to this 13-digit number for the PSTN to initiate a later callback. 
         [0037]    In addition to the above discussion in the context of a GSM network, aspects of the present disclosure may be implemented in other types of telecommunications network, such as a code division multiple access network. 
         [0038]    Systems, methods, and computer readable media comprising instructions have been shown and/or described in the above embodiments for providing temporary callback numbers for emergency calls. Although the above descriptions set forth preferred embodiments, it will be understood that there is no intent to limit the invention by such disclosure, but rather, it is intended to cover all modifications, substitutions, and alternate implementations falling within the spirit and scope of the invention. Furthermore, the embodiments are intended to cover capabilities and concepts whether they be via a loosely coupled set of components or they be converged into one or more integrated components, devices, circuits, and/or software programs.