Abstract:
A call processing system is configured to receive a call request for a first call from a mobile device operated by a user, wherein the call request comprises a user input and a caller identification, transfer a key and the caller identification to a call conference server, transfer the caller identification, the key, and a service number to a public safety answering point, and transfer the service number to the mobile device. The call conference server is configured to store the key and the caller identification, receive a second call from the public safety answering point that includes the key, receive a third call from a telecommunications relay service that includes the caller identification, and connect the third call to the second call based on the caller identification and the key.

Description:
TECHNICAL BACKGROUND 
     Telecommunication carriers provide customers with emergency calling services. In an emergency, a caller dials 911 from a telephone and the call is routed by the carrier to a public safety answering point (PSAP) facility. In addition, when an emergency call is placed a location process is automatically initiated in order to determine the location of the telephone. For instance, landline callers can be located based on their phone number. In the case of a wireless caller, the location can be determined by a variety of different methods, such as such as providing the location of the cell tower servicing a call to a PSAP, triangulation techniques, and a global position system (GPS) located within the mobile phone. 
     However, if a hearing or speech impaired individual dials 911, his or her location can be determined but he or she will not be able to communicate with the 911 operator. Alternatively, a hearing or speech impaired individual can place an emergency call to a telecommunications relay service (TRS). TRS (also known as Relay Service, or IP-Relay) allows people who are hearing impaired or speech disabled to place calls to standard telephone users. In an emergency, a hearing impaired person places an emergency call to the TRS, which in turn places a call to the PSAP. The TRS operator then relays typed messages from the hearing impaired caller as voice messages to the PSAP, and vice-versa. 
     While it is possible to determine the location of a caller who places an emergency call by dialing 911 regardless of whether a landline or mobile phone is used, present systems cannot determine the location of an emergency call placed by a caller who places an emergency call through a TRS. Therefore, if a hearing impaired individual needs to call 911, the TRS operator must ask for the street address, city, and state that the call is originating from. If this information is not provided, then the TRS operator will be unable to process the call. 
     OVERVIEW 
     Generally, a communication system comprising a call processing system and a call conference server is described herein. The call processing system is configured to receive a call request for a first call from a mobile device operated by a user, wherein the call request comprises a user input and a caller identification, transfer a key and the caller identification to a call conference server, transfer the caller identification, the key, and a service number to a public safety answering point, and transfer the service number to the mobile device. The call conference server is configured to store the key and the caller identification, receive a second call from the public safety answering point that includes the key, receive a third call from a telecommunications relay service that includes the caller identification, and connect the third call to the second call based on the caller identification and the key. A method of operating a communication system is also described herein. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a block diagram illustrating communication system  100 . 
         FIG. 2  is a flow diagram illustrating the operation of communication system  100 . 
         FIG. 3  is a block diagram illustrating communication system  300 . 
         FIG. 4  is a flow diagram illustrating the operation of communication system  300 . 
         FIG. 5  is a flow diagram illustrating the operation of communication system  300 . 
     
    
    
     DETAILED DESCRIPTION 
       FIG. 1  is a block diagram illustrating communication system  100 . Communication system  100  includes mobile communication device  101 , communication network  102 , call processing system  104 , call conference server  106 , public safety answering point  108 , and telecommunications relay service  110 . Mobile communication device  101  communicates with communication network  102 . Communication network  102  is coupled to call processing system  104 , call conference server  106 , public safety answering point  108 , and telecommunications relay service  110 . Call processing system  104  communicates with call conference server  106 , public safety answering point  108 , and telecommunications relay service  110  through communication network  102 . Call conference server  106  communicates with public safety answering point  108  and telecommunications relay service  110  through communication network  102 . Thus, mobile communication device  101  communicates with public safety answering point  108  and telecommunications relay service  110  over the systems and networks described above. 
       FIG. 2  is a flow diagram illustrating the operation of communication system  100 . As shown in  FIG. 2 , call processing system  104  receives a call request from mobile communication device  101 . The call request comprises a caller identification. The caller identification could be a telephone number associated with mobile communication device  101 , a name associated with the telephone number of mobile communication device  101 , or both. 
     Call processing system  104  then transmits a key and the caller identification to call conference server  106 . The key will be used going forward to identify the call. In response, call conference server  106  stores the key and the caller identification. Call processing system  104  also transmits a service number to mobile communication device  101 . Additionally, call processing system  104  transmits call setup signaling to public safety answering point  108 . The call setup signaling comprises the key, the caller identification, and the service number. 
     After call processing system  104  transmits the call setup signaling to public safety answering point  108 , call conference server  106  receives a call from public safety answering point  108 . The call from public safety answering point  108  is made using the service number received from call processing system  104 . Additionally, the call comprises the key. 
     Mobile communication device  101  transmits a telecommunications relay service (TRS) request to telecommunications relay service  110 . The TRS request comprises the service number and the caller identification. Additionally, after the TRS request is received by telecommunications relay service  110 , a TRS session is established between mobile communication device  101  and telecommunications relay service  110 . The TRS session allows the hearing impaired or speech disabled user of mobile communication device  101  to communicate with an operator at telecommunications relay service  110  via a telephone typewriter (TTY), a voice carry over (VCO), a personal computer, or any other type of assistive telephone device. 
     After telecommunications relay service  110  receives the TRS request call from mobile communication device  101 , call conference server  106  receives a call from telecommunications relay service  110 . The call from telecommunications relay service  110  is made using the service number received from mobile communication device  101 . Additionally, the call comprises the caller identification, which is used by call conference server  106  to connect telecommunications relay service  110  to the conference bridge used to host the conference call with public safety answering point  108 . After receiving the calls from public safety answering point  108  and telecommunications relay service  110 , call conference server  106  connects the calls to each other to create a conference call. 
     Upon completion of the conference call setup between public safety answering point  108  and telecommunications relay service  110 , the user of mobile communication device  101  will be able to communicate with the telecommunications relay service  110  operator with an assistive telephone device. Accordingly, this will allow the user to provide information relating to the emergency call to the operator at telecommunications relay service  110 , who can in turn relay that information to the operator at public safety answering point  108 . 
     Referring back to  FIG. 1 , mobile communication device  101  comprises Radio Frequency (RF) communication circuitry and an antenna. The RF communication circuitry typically includes an amplifier, filter, modulator, and signal processing circuitry. Mobile communication device  101  may also include a user interface, memory device, software, processing circuitry, or some other communication components. Mobile communication device  101  is any device capable of placing an emergency call to communication network  102 . Mobile communication device  101  may be a mobile phone, a personal computer, a laptop, or a personal digital assistant (PDA), as well other types or combinations of mobile communication devices. 
     Communication network  102  comprises wireless communication networks, wireline communication networks, or packet communication networks, as well as any combination or variation thereof. Communication network  102  communicates with mobile communication device  101 , call processing system  104 , call conference server  106 , public safety answering point  108 , and telecommunications relay service  110 . 
     Call processing system  104  comprises a computer system and a communication interface. Call processing system  104  may also include other components such a router, server, data storage system, and power supply. Call processing system  104  may reside in a single device or may be distributed across multiple devices. Call processing system  104  could be a mobile switching center, an IP multimedia subsystem, a base station controller, an access service node, or any other type, combination, or variation of call processing systems. Call processing system  104  communicates with mobile communication device  101 , call conference server  106 , and public safety answering point  108 . 
     Call conference server  106  comprises a computer system and a communication interface that allows telecommunications relay service  110  to communicate with public safety answering point  108 . In operation, call conference server  106  receives calls from public safety answering point  108  and telecommunications relay service  110 . Call conference server  106  then connects the calls from public safety answering point  108  and telecommunications relay service  110  so that an operator at public safety answering point  108  and an operator at telecommunications relay service  110  can exchange communications relating to an emergency call placed by the use of mobile communication device  101 . Call conference server  106  communicates with call processing system  104 , public safety answering point  108 , and telecommunications relay service  110 . 
     Public safety answering point  108  is any system or collection of systems capable of dispatching emergency services to the location of mobile communication device  101 . Additionally, public safety answering point  108  is capable of placing a call to call conference server  106  in response to receiving call setup signaling from call processing system  104 . Public safety answering point  108  communicates with call processing system  104  and call conference server  106 . Public safety answering point  108  also communicates with telecommunications relay service  110  through call conference server  106 . 
     Telecommunications relay service  110  comprises a computer system and a communication interface that allows hearing impaired or speech disabled users to place calls to standard telephone users via an assistive telephone device, such as a telecommunications device for the deaf (TDD), telephone typewriter (TTY), personal computer, laptop, mobile phone, PDA, or any other type of assistive telephone device. Telecommunications relay service  110  allows a hearing impaired user of mobile communication device  101  to request emergency services from public safety answering point  108 . Additionally, telecommunications relay service  110  is capable of placing a call to call conference server  106  in response to receiving a TRS request from mobile communication device  101 . Telecommunications relay service  110  communicates with mobile communication device  101 . Telecommunications relay service  110  also communicates with public safety answering point  108  through call conference server  106 . 
     In operation, communication system  100  allows a hearing or speech impaired user of mobile communication device  101  to communicate with an operator at PSAP  108 . In an example, a hearing impaired user places an emergency call to call processing system  104 . In response, call processing system  104  transmits call setup signaling to PSAP  108  and transmits a service number to mobile communication device  101 . Additionally, when the hearing impaired user places the emergency call, a TRS request is sent to TRS  110  and a TRS session is established between the user and an operator at TRS  110 . Call conference server  106  then receives calls from PSAP  108  and TRS  110  and connects the calls to each other to create a conference call. This conference call allows the hearing impaired user to communicate via an assistive keyboard device with the TRS operator, who then can relay typed messages from the user as voice messages to the PSAP operator. Likewise, the TRS operator can also relay voice messages from the PSAP operator to the user. 
       FIG. 3  is a block diagram illustrating communication system  300 . Communication system  300  includes mobile communication device  301 , communication network  302 , call processing system  304 , call conference server  306 , public safety answering point  308 , telecommunications relay service  310 , location determination system  312 , and base transceiver station  314 . Mobile communication device  301  communicates with communication network  302  through base transceiver station  314 . Communication network  302  is coupled to call processing system  304 , call conference server  306 , public safety answering point  308 , and telecommunications relay service  310 . Call processing system  304  communicates with call conference server  306 , public safety answering point  308 , and telecommunications relay service  310  through communication network  302 . Call processing system  304  communicates with location determination system  312 . Call conference server  306  communicates with public safety answering point  308  and telecommunications relay service  310  through communication network  302 . Thus, telecommunications relay service  310  communicates with mobile communication device  301  and public safety answering point  308  over the systems and networks described above. 
     Mobile communication device  301  comprises Radio Frequency (RF) communication circuitry and an antenna. The RF communication circuitry typically includes an amplifier, filter, modulator, and signal processing circuitry. Mobile communication device  301  may also include a user interface, memory device, software, processing circuitry, or some other communication components. Mobile communication device  301  is any device capable of placing an emergency call to communication network  302 . Mobile communication device  301  may be a mobile phone, a personal computer, a laptop, or a personal digital assistant (PDA), as well other types or combinations of mobile communication devices. 
     Communication network  302  comprises wireless communication networks, wireline communication networks, or packet communication networks, as well as any combination or variation thereof. Communication network  302  communicates with mobile communication device  301 , call processing system  304 , call conference server  306 , public safety answering point  308 , and telecommunications relay service  310 . 
     Call processing system  304  comprises a computer system and a communication interface. Call processing system  304  may also include other components such a router, server, data storage system, and power supply. Call processing system  304  may reside in a single device or may be distributed across multiple devices. Call processing system  304  could be a mobile switching center, an IP multimedia subsystem, a base station controller, an access service node, or any other type, combination, or variation of call processing systems. Call processing system  304  communicates with mobile communication device  301 , call conference server  306 , and public safety answering point  308 . 
     Call conference server  306  comprises interfaces and circuitry that allows telecommunications relay service  310  to communicate with public safety answering point  308 . In operation, call conference server  306  receives calls from public safety answering point  308  and telecommunications relay service  310 . Call conference server  306  then connects the calls from public safety answering point  308  and telecommunications relay service  310  so that an operator at public safety answering point  308  and an operator at telecommunications relay service  310  can exchange communications relating to an emergency call placed by the use of mobile communication device  301 . Call conference server  306  communicates with call processing system  304 , public safety answering point  308 , and telecommunications relay service  310 . 
     Public safety answering point  308  is any system or collection of systems capable of dispatching emergency services to the location of mobile communication device  301 . Additionally, public safety answering point  308  is capable of placing a call to call conference server  306  in response to receiving call setup signaling from call processing system  304 . Public safety answering point  308  communicates with call processing system  304  and call conference server  306 . Public safety answering point  308  also communicates with telecommunications relay service  310  through call conference server  306 . 
     Telecommunications relay service  310  comprises interfaces and circuitry that allow hearing impaired or speech disabled people to place calls to standard telephone users via an assistive device, such as a TDD, a TTY, personal computer, laptop, mobile phone, PDA, or any other type of assistive telephone device. Telecommunications relay service  310  allows a hearing impaired user of mobile communication device  301  to request emergency services from public safety answering point  308 . Additionally, telecommunications relay service  310  is capable of placing a call to call conference server  306  in response to receiving a TRS request from mobile communication device  301 . Telecommunications relay service  310  communicates with mobile communication device  301 . Telecommunications relay service  310  also communicates with public safety answering point  308  through call conference server  306 . 
     Location determination system  312  is any system or collection of systems capable of providing location provisioning services for emergency calls placed by mobile communication device  301 . Location determination system  312  communicates with call processing system  304 . 
     Base transceiver station  314  comprises interfaces and circuitry that allows wireless communications to be exchanged between mobile communication device  301  and communication network  302 . Base transceiver station  314  communicates with mobile communication device  301  and communication network  302 . 
       FIG. 4  is a flow diagram illustrating the operation of communication system  300 . As shown in  FIG. 4 , call processing system  304  receives an emergency call from mobile communication device  301 . The emergency call could be in the form of dialed digits, such as 9-1-1 or 9-1-1-7-1-1. Alternatively, the user input could be an emergency call button located on mobile communication device  301 . The emergency call comprises a caller identification. The caller identification could be a telephone number associated with mobile communication device  301 , a name associated with the telephone number of mobile communication device  301 , or both. The caller identification may be used to determine that the caller is hearing impaired or speech disabled. Additionally, call processing system  304  may contain a database that lists telephone numbers, user names, and whether the user is hearing impaired. In an example, call processing system  304  would use the database and the caller identification to determine that the user of mobile communication device  301  is hearing impaired. 
     Call processing system  304  then transfers a key request to location determination system  312 . The key request includes the caller identification. Location determination system  312  processes the key request to select a key that will be used going forward to identify the call. Location determination system  312  returns a key response to call processing system  304  indicating the key. Location determination system  312  also stores the caller identification in association with the key for later queries by other systems. Additionally, location determination system  312  determines the location of mobile communication device  301 , such as by employing GPS, triangulation, or other such location schemes. 
     Call processing system  304  then transmits the key and the caller identification to call conference server  306 . In response, call conference server  306  stores the key and the caller identification. Call processing system  304  also transmits a service number to mobile communication device  301 . Additionally, call processing system  304  transmits call setup signaling to public safety answering point  308 . The call setup signaling comprises the key, the caller identification, and the service number. In an example, the service number is contained in the call back number field of an initial address message. 
     After call processing system  304  transmits the call setup signaling to public safety answering point  308 , call conference server  306  receives a call from public safety answering point  308 . The call from public safety answering point  308  is made using the service number received from call processing system  304 . Additionally, the call comprises the key. 
     Public safety answering point  308  also transmits a location request to location determination system  312 . The location request indicates the key. Location determination system  312  processes the key to determine the caller identification associated with the key. Location determination system  312  then returns a response to public safety answering point  308  that indicates the location of mobile communication device  301 . Additionally, a dispatcher communicates the location of the call to response personnel responding to the emergency. 
     Mobile communication device  301  transmits a telecommunications relay service (TRS) request to telecommunications relay service  310 . The TRS request comprises the service number and the caller identification. Additionally, after the TRS request is received by telecommunications relay service  310 , a TRS session is established between mobile communication device  301  and telecommunications relay service  310 . The TRS session allows the hearing impaired or speech disabled user of mobile communication device  301  to communicate with an operator at telecommunications relay service  310  via an assistive telephone device, such as a TTY or a personal computer. 
     After telecommunications relay service  310  receives the TRS request call from mobile communication device  301 , call conference server  306  receives a call from telecommunications relay service  310 . The call from telecommunications relay service  310  is made using the service number received from mobile communication device  301 . Additionally, the call comprises the caller identification, which is used by call conference server  306  to connect telecommunications relay service  310  to the conference bridge used to host the conference call with public safety answering point  308 . After receiving the calls from public safety answering point  308  and telecommunications relay service  310 , call conference server  306  connects the calls to each other to create a conference call. 
     Upon completion of the conference call setup between public safety answering point  308  and telecommunications relay service  310 , the user of mobile communication device  301  will be able to communicate with the telecommunications relay service  310  operator with an assistive telephone device. Accordingly, this will allow the user to provide information relating to the emergency call to the operator at telecommunications relay service  310 , who can in turn relay that information to the operator at public safety answering point  308 . 
       FIG. 5  is a flow diagram illustrating the operation of communication system  300 . As shown in  FIG. 5 , call processing system  304  receives an emergency call from mobile communication device  301 . The emergency call could be in the form of dialed digits, such as 9-1-1, 9-1-1-7-1-1, 1+911-711, *(star)-911-711, or #-911-711, including any combinations or variations thereof. It should be understood that digits other than those described could be dialed to make an emergency call. Alternatively, the user input could be an emergency call button located on mobile communication device  301 . The emergency call comprises a caller identification. In this example, the caller identification is a telephone number associated with mobile communication device  301 . 
     Call processing system  304  then transfers a key request to location determination system  312 . The key request includes the caller identification. Location determination system  312  processes the key request to select a key that will be used going forward to identify the call. Location determination system  312  returns a key response to call processing system  304  indicating the key. Location determination system  312  also stores the caller identification in association with the key for later queries by other systems. Additionally, location determination system  312  determines the location of mobile communication device  301 , such as by employing GPS, triangulation, or other such location schemes. 
     Call processing system  304  then transmits the key and the caller identification to call conference server  306 . In response, call conference server  306  stores the key and the caller identification. Additionally, call processing system  304  transmits call setup signaling to public safety answering point  308 . The call setup signaling comprises the key, the caller identification, and a service number. In an example, the service number is a phone number that will be transmitted to public safety answering point  308  and telecommunications relay service  310 . 
     After call processing system  304  transmits the call setup signaling to public safety answering point  308 , call conference server  306  receives a call from public safety answering point  308 . The call from public safety answering point  308  is made using the service number received from call processing system  304 . Additionally, the call comprises the key. 
     Public safety answering point  308  also transmits a location request to location determination system  312 . The location request indicates the key. Location determination system  312  processes the key to determine the caller identification associated with the key. Location determination system  312  then returns a response to public safety answering point  308  that indicates the location of mobile communication device  301 . Additionally, a dispatcher communicates the location of the call to response personnel responding to the emergency. 
     Call processing system  304  transmits a telecommunications relay service (TRS) request to telecommunications relay service  310 . The TRS request comprises the service number and the caller identification. Additionally, after the TRS request is received by telecommunications relay service  310 , a TRS session is established between mobile communication device  301  and telecommunications relay service  310 . The TRS session allows the hearing impaired or speech disabled user of mobile communication device  301  to communicate with an operator at telecommunications relay service  310  via an assistive telephone device, such as a TTY or a personal computer. 
     After telecommunications relay service  310  receives the TRS request call from call processing system  304 , call conference server  306  receives a call from telecommunications relay service  310 . The call from telecommunications relay service  310  is made using the service number received from call processing system  304 . Additionally, the call comprises the caller identification, which is used by call conference server  306  to connect telecommunications relay service  310  to the conference bridge used to host the conference call with public safety answering point  308 . After receiving the calls from public safety answering point  308  and telecommunications relay service  310 , call conference server  306  connects the calls. 
     Upon completion of the conference call setup between public safety answering point  308  and telecommunications relay service  310 , the user of mobile communication device  301  will be able to communicate with the telecommunications relay service  310  operator with an assistive telephone device. Accordingly, this will allow the user to relate information relating to the emergency call to the operator at telecommunications relay service  310 , who can in turn relay that information to the operator of the public safety answering point  308 . 
     Advantageously, communication systems  100  and  300  allow for the ability to recognize if a caller is hearing impaired or speech disabled and to allow the caller to communicate with an emergency PSAP operator through a TRS operator. The TRS operator can understand both the text communications from the caller and the voice communications from the PSAP operator and can relay information between the caller and the PSAP operator. Furthermore, communication system  300  also allows for automatic location determination of the caller to be initiated upon receipt of an emergency call without the need for the caller to communicate their location to the TRS or PSAP operators. 
     The above description and associated figures teach the best mode of the invention. The following claims specify the scope of the invention. Note that some aspects of the best mode may not fall within the scope of the invention as specified by the claims. Those skilled in the art will appreciate that the features described above 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 above, but only by the following claims and their equivalents.