Abstract:
Networks and methods are disclosed for providing an indication of the capability of a communication network for serving special number calls. Before a user places a special number call, the communication network determines the capability of the communication network for serving a special number call, and provides the indication of the network capability to the user. The user is thus kept aware of the quality of the special number service available to them through the communication network.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The invention relates to communications and, in particular, to providing an indication to a user of the capabilities of a communication network for handling special number calls, such as 9-1-1 calls, prior to the user placing a special number call over the communication network. 
     2. Statement of the Problem 
     In the United States, basic 9-1-1 service and Enhanced 9-1-1 service (E9-1-1) were developed for landline-based telephony as emergency reporting services where a calling party can dial 9-1-1 in emergency situations. When a 9-1-1 call is placed, the call is answered at a Public Safety Answering Point (PSAP, also known as a “Public Safety Access Point”). An operator at the PSAP converses with the calling party to determine information on the emergency situation. For instance, the operator may ask the calling party for his/her name, the nature of the emergency, the location of the emergency, etc. Based on the gathered information, the operator contacts emergency personnel to respond to the emergency. E9-1-1 has the additional features of automatically providing the operator with some information on the calling party. For instance, E9-1-1 service includes the features of Automatic Number Identification (ANI) and Automatic Location Identification (ALI). With ANI, the operator at the PSAP is automatically provided with the telephone number of the phone placing the 9-1-1 call to allow for call back. With ALI, the PSAP queries an ALI database for information on the physical location of the calling party&#39;s phone. An ALI database stores records of telephone numbers with each record containing information on a physical location (such as a street address) corresponding with a telephone number or another key. Responsive to a query from the PSAP, the ALI database returns the location information for the calling party. With the telephone number and the location information, the operator can more effectively handle the 9-1-1 call. Other countries have emergency services similar to this. 
     E9-1-1 service is more easily implemented for landline phones where a location of a phone is fixed. Mobile devices, such as cell phones, PCS phones, VoIP phones, etc., present another problem. The locations of mobile devices are not fixed by definition, which makes determining their location more of a challenge as compared to landline phones. Regulatory bodies, such as the Federal Communications Commission (FCC) in the United States, have set forth regulations that carrier networks, such as cellular networks, must be able to determine the location of mobile devices for 9-1-1 calls. If a mobile device is GPS enabled, then the device can provide its location to the carrier network. If the mobile device is not GPS enabled, then the carrier network has the duty to determine the location of the mobile device. A wireless carrier network, such as a cellular or PCS network, can estimate the location of a mobile device based on the location of the cell presently providing service to the mobile device, such as through a cell identifier (cell ID). The wireless carrier network may also use triangulation among multiple cells, time of arrival (TOA) information indicating the time it takes for a wireless signal from a mobile device to reach a base station, and other data to more accurately determine the location of the mobile device. The location of the mobile device may then be used to select the appropriate PSAP to handle a 9-1-1 call, and to provide the location of the mobile device to the PSAP. 
     Mobile VoIP also presents a problem of determining the location of the calling party. Some VoIP service providers have a VoIP user predefine a location, such as his/her home address, when the VoIP user signs up for service. If the VoIP user uses their VoIP phone away from their home address, then the VoIP service provider may require that the VoIP user enter their present address when registering with the VoIP network. 
       FIG. 1  illustrates a communication network  100  for providing 9-1-1 service in the prior art. Communication network  100  includes a wireless carrier network  110 , an emergency services network  120 , and a positioning server  132 . Wireless carrier network  110  includes a base station  112  and a Mobile Switching Center (MSC)  114  that provide telephone service to a mobile phone  116 . Positioning server  132  determines the location of mobile phone  116 , and determines where to route 9-1-1 calls based on the location of mobile phone  116 . Positioning server  132  may include the functionality of a Location Information Services (LIS) server, a Position Determining Entity (PDE) server, and/or a Serving Mobile Location Center (SMLC) server. Emergency services network  120  includes a selective router  122 , a PSAP  124 , and an ALI database  126 . 
     The following illustrates a typical 9-1-1 call in communication network  100 . Assume that a user of mobile phone  116  places a 9-1-1 call. Base station  112  receives the call, and transmits the call to MSC  114 . MSC  114  identifies the call as a 9-1-1 call, and transmits an indication of the 9-1-1 call to positioning server  132 . Responsive to the indication of the 9-1-1 call, positioning server  132  determines the location of mobile phone  116 . Based on the location of mobile phone  116 , positioning server  132  generates routing information for the call in order to route the call to a PSAP responsible for mobile phone  116 . The routing information typically includes an Emergency Service Number (ESN) that represents an emergency service zone corresponding with the location of mobile phone  116 , an Emergency Service Routing Key (ESRK), and other information. Positioning server  132  then transmits the routing information to MSC  114 , which routes the 9-1-1 call to selective router  122  based on the routing information. 
     Selective router  122  queries a selective router database (not shown) to select the appropriate PSAP  124  to handle the call based on the ESN. Selective router  122  then routes the call to PSAP  124 . PSAP  124  receives the call that includes the call back number (ANI) of mobile phone  116  and receives the ESRK. PSAP  124  then queries ALI database  126  based on the ESRK of mobile phone  116  to obtain the present location of mobile phone  116 . ALI database  126  communicates with positioning server  132  to obtain the location associated with the ESRK of mobile phone  116 . ALI database  126  then provides the location of mobile phone  116  to PSAP  124 , and an operator at PSAP  124  handles the 9-1-1 call. 
     One problem with present communication networks is that a user may be in an area where the 9-1-1 capabilities of the network are poor, and the user may not know that the 9-1-1 capabilities are poor. In one example, a mobile user may travel to an area where a wireless carrier network is not able to accurately determine the location of the mobile user. As a consequence of not being able to accurately determine the location, the wireless carrier network may not be able to determine where to route a 9-1-1 call. Even if the call is routed correctly, a PSAP serving the 9-1-1 call may not receive accurate location information from the ALI database and may have a hard time determining the actual location of the mobile user. 
     In another example, VoIP service providers sometimes struggle with how to determine the location of VoIP users. Certain areas of VoIP networks are not presently configured to determine the location of a VoIP phone in the event of a 9-1-1 call. Unfortunately, the VoIP user may not have an idea that they are in an area where the VoIP network can only provide limited 9-1-1 capabilities or no 9-1-1 capabilities at all. Similar problems exist for other special number calls or abbreviated dialing calls, such as 1-1-2 calls in Europe. 
     SUMMARY OF THE SOLUTION 
     The invention solves the above and other problems by providing an indication of the capability of a communication network to serve a special number call, such as a 9-1-1 call, to a user of a communication device. The communication device may then provide the indication to the user through one or more LEDs, a text message, a web page, interactive voice, etc. The user can advantageously determine the capabilities of the communication network to serve a special number call before a special number call is actually placed over the communication network. The user is thus kept aware of the network capabilities before an emergency situation or other special number situations are encountered. 
     One embodiment of the invention includes a method of providing the indication of the network capabilities to a user of a communication device. One step of the method includes determining location information for the communication device. Another step of the method includes determining routing information for a simulated special number call to route the simulated special number call to an answering point (e.g., PSAP). Another step of the method includes determining a network capability of the communication network for serving the simulated special number call based on the location information, the routing information, and/or other information. After the network capabilities are determined, another step of the method includes providing an indication of the network capability to the communication device to notify a user of the network capability of the communication network for serving an actual special number call prior to the user placing the actual special number call. For instance, the indication may be “Good”, “Average”, “Poor”, or some other quantifier indicating the network capabilities. The user can advantageously be notified if acceptable network capabilities are available or if poor or no network capabilities are available for special number calls. 
     The invention may include other exemplary embodiments described below. 
    
    
     
       DESCRIPTION OF THE DRAWINGS 
       The same reference number represents the same element or same type of element on all drawings. 
         FIG. 1  illustrates a communication network for providing 9-1-1 service in the prior art. 
         FIG. 2  illustrates a communication network adapted to serve special number calls in an exemplary embodiment of the invention. 
         FIG. 3  is a flow chart illustrating a method of operating a communication network in an exemplary embodiment of the invention. 
         FIG. 4  illustrates a capability determination system in an exemplary embodiment of the invention. 
         FIG. 5  illustrates another communication network adapted to serve an emergency call in an exemplary embodiment of the invention. 
         FIG. 6  illustrates another communication network adapted to serve an emergency call in an exemplary embodiment of the invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       FIGS. 2-6  and the following description depict specific exemplary embodiments of the invention to teach those skilled in the art how to make and use the invention. For the purpose of teaching inventive principles, some conventional aspects of the invention have been simplified or omitted. Those skilled in the art will appreciate variations from these embodiments that fall within the scope of the invention. Those skilled in the art will appreciate that the features described below can be combined in various ways to form multiple variations of the invention. As a result, the invention is not limited to the specific embodiments described below, but only by the claims and their equivalents. 
       FIG. 2  illustrates a communication network  200  adapted to serve a special number call in an exemplary embodiment of the invention. Special number calls, also referred to as abbreviated number calls, are calls to particular numbers where the communication network provides a special service to the calling party. Examples of special number calls include 9-1-1 calls in the United States, and 1-1-2 calls in Europe. Communication network  200  is illustrated as including a communication device  212 , a routing network  214 , and a special number network  220 . Communication device  212  comprises any device adapted to place a special number call to special number network  220 , such as a landline phone, a mobile phone, a VoIP phone, etc. Routing network  214  comprises any network that provides communication between communication device  212  and another network, system, or device. Routing network  214  may be a circuit-switched network or a packet-based network. Special number network  220  comprises any network adapted to serve a special number call or abbreviated number call in some manner. One example of a special number network  220  is an emergency services network adapted to serve emergency calls, such as 9-1-1 calls. Special number network  220  includes an answering point  222  adapted to receive the special number calls, and an ALI database  224  adapted to provide location information to answering point  222 . 
     Communication network  200  is further illustrated as including a capability determination system  232 , a positioning system  234 , and an information system  238 . Capability determination system  232  comprises any system, server, or application adapted to determine the capability of a communication network to serve a special number call as will be described in more detail herein. In making this determination, capability determination system  232  may receive data or information from positioning system  234 , information system  238 , and/or other systems not shown in  FIG. 1 . 
     Positioning system  234  comprises any system, server, or application adapted to determine or identify location information for a communication device, and to determine or identify routing information for a special number call. Examples of positioning system  234  may include a mobile positioning center (MPC), a VoIP positioning center (VPC), a Location Information Services (LIS) server, a Position Determining Entity (PDE) server, a Serving Mobile Location Center (SMLC) server, a switch, a static mapping table that maps user identifiers (i.e., directory numbers) to physical addresses, etc. 
     Information system  238  comprises any system, server, or application adapted to determine or identify some other type of information for a special number call. Capability determination system  232  may process location information and routing information from positioning system  234 , or other information from other systems. Information system  238  represents any other system or systems that generate information used by capability determination system  232  to determine the capability of a communication network to serve a special number call. 
     Prior to a user of communication device  212  placing a special number call, communication network  200  operates as described in  FIG. 3  to determine the capability of communication network  200  to serve a special number call. In other words, communication network  200  determines its capability not in response to the user of communication device  212  placing a special number call, but rather determines its capability responsive to some other trigger. The trigger may be communication device  212  registering with capability determination system  232 , communication device  212  registering with a carrier network (not shown) for communication device  212 , capability determination system  232  detecting movement of communication device  212  over a particular threshold, a time period expiring, or another type of trigger. 
       FIG. 3  is a flow chart illustrating a method  300  of operating communication network  200  in an exemplary embodiment of the invention. The steps of the flow chart in  FIG. 3  are not all inclusive and may include other steps not shown. 
     In step  302 , positioning system  234  determines location information for communication device  212 . The location information may include a physical location of communication device  212 , such as a street address, a latitude/longitude, etc. The location information may also include an uncertainty of the physical location of communication device  212 , where the uncertainty indicates how accurate or precise the physical location is for communication device  212 . For instance, an indication of “10” may indicate that positioning system  234  is confident in the reliability of the location of communication device  212 . An indication of “1” may indicate that positioning system  234  is not confident in the reliability of the location of communication device  212 . The uncertainty may be generated as part of a triangulation algorithm, or may be generated in other desired ways. 
     Positioning system  234  may determine the location information in a variety of ways. In one example, if communication device  212  is a wireline phone, then positioning system  234  may include a table that maps physical addresses to directory numbers. In another example, if communication device  212  is a wireless phone, then positioning system  234  may determine the location of communication device  212  based on GPS information, triangulation among multiple cells, time of arrival (TOA) information, or other data. In another example, if communication device  212  is a VoIP phone, then positioning system  234  may determine the location of communication device  212  based on an address specified by the user upon setup of the VoIP service, based on an address entered by the user when communication device  212  registers with a carrier network, etc. 
     In step  304 , positioning system  234  determines routing information for a simulated special number call from communication device  212  to route the simulated special number call to answering point  222 . Positioning system  234  determines the routing information based on the location of communication device  212  and other information. Because an actual special number call has not been placed at this time, positioning system  234  determines routing information for a “simulated” special number call to mimic how an actual special number call would be routed for communication device  212 . The routing information may indicate an Emergency Service Zone (ESZ), an Emergency Service Number (ESN), or any other information to route the special number call to the appropriate answering point. 
     In step  306 , information system  238  determines other information for a simulated special number call from communication device  212 . Depending on the network capabilities that are to be determined, capability determination system  232  may receive data from positioning system  234  and/or information system  238 . Information system  238  is intended in this embodiment to provide any other information that capability determination system  232  may need or want to determine the network capability. As an example, information system  238  may provide an indication that a wireless carrier network is a Phase 0 network, a Phase 1 network, or a Phase 2 network. In another example, information system  238  may provide an indication of the capability of answering point  222  for handling special number calls. 
     In step  308 , capability determination system  232  determines a network capability of communication network  200  for serving special number calls, such as the simulated special number call, based on the location information provided by positioning system  234 , based on the routing information provided by positioning system  234 , and/or based on other information provided by information system  238 . The network capability represents the level or quality of special number service that communication network  200  could provide communication device  212  for a special number call. 
     In one example, capability determination system  232  may process the location information to identify a location of communication device  212  and an uncertainty of the location of communication device  212 . Capability determination system  232  may further determine the network capability of communication network  200  based on the location of communication device  212  and the uncertainty of the location. 
     In another example, capability determination system  232  may identify an answering point  222  for the simulated special number call and an amount of data that can be provided to answering point  222 . Capability determination system  232  may further determine the network capability of communication network  200  based on the identified answering point  222  and the amount of data that can be provided to answering point  222 . 
     In another example, capability determination system  232  may determine if a call back number is identified for the simulated special number call, and determine the network capability of communication network  200  based on whether a call back number is identified. 
     In another example, capability determination system  232  may identify an answering point  222  to handle the simulated special number call, and determine the capabilities of answering point  222  to handle the simulated special number call. Capability determination system  232  may further determine the network capability of communication network  200  based on the capabilities of answering point  222 . For instance, the capabilities of answering point  222  may include whether answering point  222  can provide a physical address to an operator or can provide a latitude/longitude to an operator. The capabilities of answering point  222  may include what type of data that answering point  222  can handle or process, such as video, text messages, etc. Capability determination system  232  may query a database that stores information on each answering point in communication network  200  to determine the capabilities of answering point  222 . Capability determination system  232  may process any other desired information to determine the network capability. 
     In step  310 , capability determination system  232  provides an indication of the network capability to communication device  212  to notify the user of the network capability of communication network  200  for serving an actual special number call. Capability determination system  232  provides this indication prior to the user placing an actual special number call so that the user is aware of the capability of communication network  200  for serving special number calls. The indication of the network capability may take on many desired forms, such as a signal intended to illuminate one or more LEDs on communication device  212 , a text message, a web page, an interactive voice message, etc. Responsive to receiving the indication, communication device  212  displays or otherwise provides the indication of the network capability to the user to notify the user of the network capability prior to the user placing an actual special number call. 
     According to method  300 , communication network  200  advantageously keeps the user of communication device  212  aware of its capability to serve special number calls. This can particularly be advantageous for mobile users, such as cellular users or VoIP users. Because the capabilities of VoIP networks to serve special number calls are presently an issue, method  300  provides an effective mechanism to keep users aware of the capability of a VoIP network to handle special number calls. 
       FIG. 4  illustrates capability determination system  232  in an exemplary embodiment of the invention. Capability determination system  232  includes a first interface  402  adapted to communicate with communication device  212 , a processing system  404 , and a second interface  406  adapted to communicate with positioning system  234  and/or information system  238 . Processing system  404  comprises any circuitry, logic, single processing device, or a group of inter-operational processing devices operable to execute code or instructions. Processing system  404  may execute one or more algorithms to determine the network capability of communication network  200  to serve special number calls. 
     When in operation, interface  406  receives location information, routing information, and/or other information from positioning system  234  and/or information system  238 . Processing system  404  processes the location information, the routing information, and/or the other information to determine a network capability of communication network  200  for serving special number calls. Interface  402  then provides an indication of the network capability to communication device  212  to notify the user of the network capability of communication network  200  for serving an actual special number call. 
       FIG. 5  illustrates another communication network  500  adapted to serve an emergency call in an exemplary embodiment of the invention. An emergency call may comprise a 9-1-1 call in the United States, a 1-1-2 call in Europe, or another type of emergency call. Although emergency calls are illustrated in this embodiment, communication network  500  may serve other types of special number calls or abbreviated number calls in a similar manner. 
     In this embodiment, communication network  500  includes a VoIP carrier network  510 , an emergency services network  520 , and a gateway  540  between the networks. VoIP carrier network  510  includes a VoIP phone  512 , a VoIP server  514 , and a LIS  516 . Emergency services network  520  includes a selective router  522 , a PSAP  524 , and an ALI database  526 . Communication network  500  is further illustrated as including a capability determination system  532 , a positioning system  534 , and an information system  538 . 
     When in operation, VoIP phone  512  registers with VoIP server  514 . VoIP phone  512  may use Session Initiation Protocol (SIP) to register and communicate with VoIP server  514 . LIS  516  stores location information for VoIP phone  512 . The location information may be pre-defined for VoIP phone  512  as a static location, or may be defined by the user of VoIP phone  512  during registration. Responsive to the registration of VoIP phone  512 , VoIP server  514  transmits a message to capability determination system  532 , which is a trigger for capability determination system  532  to initiate the process of determining the capability of communication network  500  to serve an emergency call. VoIP server  514  also transmits a query or message to positioning system  534  and/or information system  538  as is done for an actual emergency call even though an emergency call has not been placed by VoIP phone  512 . VoIP server  514  initiates the process of serving an emergency call, but the call is a simulated emergency call. 
     Positioning system  534  receives the query from VoIP server  514  and determines location information for VoIP phone  512  (if available). For instance, positioning system  534  may query LIS  516  to identify the location of VoIP phone  512 . Positioning system  534  may also query LIS  516  for an uncertainty of the location, or generate an uncertainty. If positioning system  534  identifies a location for VoIP phone  512 , then positioning system  534  may query the user of VoIP phone  512  to verify the identified location, especially if the uncertainty of the location indicates that the location may be suspect. For instance, positioning system  534  may transmit a web page, a text message, or some other type of information that includes an address identified for the user to VoIP phone  512 . If the address is correct, then the user can verify that the address is correct. If the location is incorrect, then the user can either indicate that the address is incorrect or enter the correct address. In another instance, positioning system  534  may transmit a web page, a text message, or some other type of information to VoIP phone  512  that includes a map indicating the identified location for the user. If the location on the map is correct, then the user can verify that the identified location is correct. If the location on the map is incorrect, then the user can either indicate that the location is incorrect or indicate the correct location on the map. Either way, positioning system  534  has a verified location for the user of VoIP phone  512 . 
     If positioning system  534  is not able to identify a location for VoIP phone  512 , then positioning system  534  may query the user of VoIP phone  512  to provide their present location. For instance, positioning system  534  may transmit a web page, a text message, or some other type of information asking the user to enter his/her present location. Positioning system  534  can then store the provided location information. 
     Positioning system  534  then processes the location information of VoIP phone  512  to determine routing information for the simulated emergency call. The routing information indicates which PSAP  524  is appropriate to serve the emergency call. Each PSAP in the emergency services network  520  is assigned to an emergency service zone. Positioning system  534  identifies the emergency service zone associated with the location of VoIP phone  512 , and assigns an Emergency Service Query Key (ESQK) for the simulated emergency call that is associated with the identified emergency service zone. The ESQK is dynamically assigned to the emergency call to enable routing to the proper PSAP and enable retrieval of a call back number and the location information. Positioning system  534  then transmits the location information and the routing information to capability determination system  532 . Information system  538  may provide other information to capability determination system  532  as needed or desired. 
     Capability determination system  532  determines a network capability of communication network  500  for serving the simulated emergency call based on the location information provided by positioning system  534 , based on the routing information provided by positioning system  534 , and/or based on other information provided by information system  538 . The network capability represents the level or quality of emergency service that communication network  500  could provide VoIP phone  512  for an emergency call. 
     As an example, the network capability may depend on the precision of the location identified for VoIP phone  512 , such as a state, a county, a city, a street address, latitude/longitude, etc. The network capability may depend on whether positioning system  534  can identify a PSAP for the simulated emergency call. The network capability may depend on whether a call back number can be identified for the simulated emergency call. The network capability may depend on whether a dedicated trunk is down or congested between gateway  540  and selective router  522 , or between selective router  522  and PSAP  524 . The network capability may depend on the capabilities of PSAP  524  to handle an emergency call. For instance, the capabilities of PSAP  524  may include whether PSAP  524  can provide a physical address to an operator or can provide a latitude/longitude to an operator. The capabilities of PSAP  524  may include what type of data that PSAP  524  can handle or process, such as video, text messages, etc. There may be many other factors that capability determination system  532  considers in determining the network capability. 
     Capability determination system  532  then provides an indication of the network capability to VoIP server  514 , and VoIP server  514  forwards the indication to VoIP phone  512 . Capability determination system  532  may alternatively provide the indication directly to VoIP phone  512 . Capability determination system  532  provides this indication prior to the user placing an actual emergency call so that the user is aware of the capability of communication network  500  for serving emergency calls. 
     The network capability may be a grade such as “Good”, “Average”, or “Poor”. VoIP phone  512  may have three LEDs (green/yellow/red) associated with the grades “Good”, “Average”, and “Poor”. When VoIP phone  512  receives the indication of network capability from capability determination system  532 , VoIP phone  512  can illuminate the proper LED to indicate the grade of network capability. 
     The VoIP service provider may also use the network capability to restrict communication service to VoIP phone  512 . The VoIP service provider may define capability standards for serving emergency calls that VoIP network  510  has to meet before service is provided to VoIP phone  512 . If the network capability does not meet the defined capability standards, then VoIP server  514  may restrict the VoIP service to VoIP phone  512 . As an example, if capability determination system  532  determines that a location for VoIP  512  cannot be identified or that the precision or certainty of the location is not acceptable, then capability determination system  532  indicates this in the network capability determination, such as giving a “Poor” grade. The VoIP service provider may define that a location of VoIP phone  512  has to be determined with an acceptable precision before VoIP server  514  is allowed to provide VoIP service to VoIP phone  512 . 
       FIG. 6  illustrates another communication network  600  adapted to serve an emergency call in an exemplary embodiment of the invention. Communication network  600  is substantially similar in configuration and operation as communication network  500 , except that there is peer-to-peer communication between VoIP phone  512  and emergency services network  520 . In this embodiment, VoIP phone  512  is a peer-to-peer device that subscribes to an emergency call service, such as a 9-1-1 service in the United States. 
     Although specific embodiments were described herein, the scope of the invention is not limited to those specific embodiments. The scope of the invention is defined by the following claims and any equivalents thereof.