T-Mobile USA, Inc.

William Michael Hooker

Shujaur Rehman Mufti

Hsin-Fu Henry Chiang

Boris Antsev

Shelby Seward

Adrian T Synal

Mohammed Al-Mehdar

Michele Kinsey

Gunjan Nimbavikar

Christopher Harvey Joul

Suresh Thanneeru

Alexandru Catalin Ionescu

Lin Zhang

Hang Hoi Yau

Tong Luo

Hyung Keun Choi

Srinivasa Rao Bodapotula

Suryo Sukendro

Syed Hassan Raza

Anthony James Wageman

Solutions for placing an emergency call over a wireless network improve speed and reliability by prioritizing using an internet protocol (IP) multimedia subsystem (IMS) packet data network (PDN) or protocol data unit (PDU) network (PDN/PDU) over domain reselection when a call attempt fails over an emergency PDN/PDU (EPDN/EPDU). Examples include establishing an IMS PDN/PDU session for a user equipment (UE) over a wireless network; attempting, by the UE, an emergency call using an EPDN/EPDU over the wireless network; and based on at least a failure of the emergency call over the EPDN/EPDU, reattempting the emergency call using the IMS PDN/PDU over the wireless network. Based on at least a failure of the emergency call over the IMS PDN/PDU, the UE performs domain reselection and reattempts the emergency call using a second wireless network. In some examples, wireless networks transmit a network policy for handling the emergency call to the UE.

IMS PDN/PDU for emergency call

The system receives a SIP call from a UE associated with a user, where the SIP call includes multiple fields, and where a field among the multiple fields indicates that the SIP call is the open-line call. The system receives a first indication that the UE associated with a callee has generated a notification to the callee of the SIP call. Upon identifying the SIP call as the open-line call and receiving the first indication, the system sends a first message to the UE associated with the caller that the UE associated with the callee has generated the notification. The first message indicates to the UE associated with the caller to generate a first inaudible notification indicating that the UE associated with the callee generated the notification.

Inaudibly notifying a caller of a status of an open-line call

The system receives a SIP call from a UE associated with the user. The SIP call includes a call setup phase and a data transfer phase, where the call setup phase precedes the data transfer phase. The call setup phase includes an exchange of multiple header fields. The system obtains the multiple header fields from the SIP call. The system determines that the call is an open-line call by identifying an optional field within the multiple header fields, where the optional field indicates that the call is the open-line call. The open-line call indicates that the user of the UE cannot engage in a conversation with a receiver of the open-line call. Upon determining that the call is the open-line call, the system notifies an operator receiving the SIP call to not engage in an audible conversation with the user.

Automatically identifying a call associated with a wireless telecommunication network as an open-line call

Techniques for determining a location of a roaming device on a host telecommunications network are described herein. The host telecommunications network can implement a location server to determine a geographical location of a user equipment (UE) that generates an emergency message to an emergency service center. The location server can exchange data representing device information, network information, or user information with a subscriber server of a home telecommunications network, and use the data to initiate determination of the geographical location. The location server can initiate, establish, maintain, or otherwise determine a geographical location of the UE for sending to the emergency service center (e.g., to enable the UE to exchange text communications with a Public Service Answering Point).

Roaming device location determination for emergency communications

An emergency route back number (ERBN) may be assigned for use in emergency calls. A telecommunication network associated that may be associated with a wireless service provider, may identify an emergency call directed to an emergency number (e.g., 9-1-1) that originated from a device that is not associated with a unique phone number such as a shared line, or a communication that utilizes some other indicator to establish the emergency call (e.g., an email address, or some other identifier). When an emergency call is detected that does not have a dedicated phone number, an ERBN is assigned to the communication. This ERBN may be reserved for some period of time after the emergency call ends such that emergency contact centers are able to reach callers back in case of dropped calls, fails, and/or additional emergency services that may need to reach the callers directly.

Temporary assignment of emergency route back

Text based 911 communication

Techniques for handling emergency calls in a fifth generation (5G) telecommunication network are discussed herein. Some 5G-compatible user equipment (UEs) support 5G emergency calls, while other 5G-compatible UEs do not support 5G emergency calls. If a UE supports 5G emergency calls, the 5G telecommunication network may instruct the UE during network registration to use the 5G telecommunication network for any emergency calls attempted later. However, if a UE does not support 5G emergency calls, the 5G telecommunication network may instruct the UE during network registration to instead use Long-Term Evolution (LTE) emergency fallback procedures for emergency calls. Such LTE emergency fallback procedures can cause the 5G telecommunication network to steer the UE to LTE for an emergency call almost immediately after receiving a service request from the UE, even though the 5G telecommunication network itself supports emergency calls.

Emergency service fallback based on user equipment capability

One or more timers can be used by an originating UE during setup of a communication session. The timer(s) can be triggered by an originating UE receiving a response from a node of a telecommunications network. The timer(s) can further be terminated by a particular termination event during a remainder of the session setup, so long as the termination event occurs before timeout of the timer(s).

Call setup timer triggered by network response

Systems and methods are described herein for handling a request for a text message session on an IP multimedia subsystem (IMS) capable network. For example, a device is communicatively coupled at a location of the IMS capable network. The method includes receiving a request from the device for a text message session on the IMS capable network and determining whether the IMS capable network supports next generation 911 (NG911) or interim text-to-911 at the location of the device. Upon determining that the IMS capable network is incapable of supporting NG911, redirecting the request for the text message session to a text control center (TCC). The method further includes causing the TCC to establish the text message session with a public safety answering point (PSAP) that supports text-to-911.

Modernized messaging compatibility with interim text-to-911

Systems and methods for testing a text-to-911 system of a public safety answering point (PSAP) are described herein. The systems and methods provide for an administrative line that the PSAP, whereby a user can test the PSAP and determine if information that would be used by the PSAP in the case of an emergency is correct.

Testing emergency text services

A system and method for performing an emergency call route failover between an Emergency Call Session Control Function (E-CSCF) and multi-homed remote end-point functions such as Border Gateway Control Function (BGCF)/Media Gateway Control Function (MGCF) or Interconnection Border Control Function (IBCF) in an Internet Protocol Multimedia Subsystem (IMS) uses Session Initiation Protocol (SIP) and/or Domain Name System (DNS) methods. The E-CSCF and/or a DNS server monitors the availability of the remote end-points to create a peer list of route options. The E-CSCF or the DNS server selects a route option from the peer list to route an emergency call to an appropriate Public Safety Answering Point (PSAP). In the event that the route option fails, the E-CSCF fails over to the next available route option to route the emergency call.

Systems and methods for emergency call route failover

Multiple timers used by a device during setup of a communication session may include a first timer and a second timer, each configured to expire after different periods of time, and each configured to start in response to the device sending a Session Initiation Protocol (SIP) request using a SIP INVITE method. The first timer is stopped on receipt of the first SIP response, which may include a 100. Trying SIP response, while the second timer is stopped on receipt of a non-100 Trying SIP response. If the first timer expires, the device may send an additional SIP request using the SIP INVITE method as a retry mechanism while the second timer continues to run. If the second timer expires, the device may halt the session setup and reattempt using a different type of access network.

Call setup logic with emerg-request-non-100 timer

One or more timers can be used by an originating UE during setup of a communication session. The timer(s) can be triggered by an originating UE sending a request or receiving a response that uses a first signaling protocol. The timer(s) can further be terminated by the originating UE sending a request or receiving a response that uses a second signaling protocol different from the first signaling protocol, so long as the request/response using the second signaling protocol occurs before timeout of the timer(s).

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Bellevue, WA, United States of America

William Michael Hooker