T-mobile Usa, Inc.

Karthik Chandrasekaran

Venkata Kondeti

Muhilan Vamadevan

Srinivasan Sridharan

Systems may establish a Session Initiated Protocol (SIP) session during a Home Subscriber Server (HSS) outage. The systems may include Network Functions (NF) that perform steps for establishing the SIP session and/or bypassing the HSS experiencing the outage. For instance, an Interrogating (I)-Call Session Control Function (CSCF) may modify a terminating message received from a User Equipment (UE) to generate a modified terminating message, and send one or more instances (e.g., forks) of the modified terminating message to one or more candidate Serving (S)-CSCFs. A particular S-CSCF of the candidate S-CSCFs may comprise the registered S-CSCF and may respond to an instance of the modified terminating message. In some embodiments, the I-CSCF may establish the SIP session by sending an instance of the modified terminating message to a designated S-CSCF. The designated S-CSCF may determine which candidate S-CSCF comprises the registered S-CSCF, for instance, by querying the candidate S-CSCFs.

Session initiated protocol (SIP) session establishment with a home subscriber server (HSS) outage

Described herein are techniques, devices, and systems for handling Session Initiation Protocol (SIP) messages with malformed header fields. A communication device that receives a SIP message from an additional communication device may identify one or more identified header fields of a plurality of first header fields in a message header of the SIP message that correspond to (e.g., match) one or more second header fields in a list of second header fields accessible to the communication device. If the communication device determines that the one or more identified header fields are not malformed, the communication device may process the SIP message without regard to remaining header fields in the message header. If, however, the communication device determines that at least one identified header field of the one or more identified header fields is malformed, the communication device may reject the SIP message.

Handling SIP messages with malformed header fields

Techniques for optimizing terminating access domain selection (TADS) flow for a Fifth Generation (5G) standalone (SA) capable interworking device with legacy Fourth Generation (4G) voice over long term evolution (VoLTE) network are discussed herein. A 5G SA capable user equipment (UE) may receive a voice call from any generation network. To receive a 5G voice call on an IP Multimedia Subsystem (IMS) network, a terminating UE must be currently connected to a 5G SA network. However, the system has to determine the currently connected radio access technology (RAT) type before establishing a connection; otherwise, attempts to establish a 5G NR connection would result in network call completion errors. The system may configure a home subscriber server to receive a TADS request for the terminating UE and return a TADS status.

Optimizing terminating access domain selection for a 5G SA interworking device with legacy network

Methods, a system, and computer readable media are disclosed to provide an enhanced Communication Waiting applications service. Enhancements include a method for handling an incoming communication received before an outgoing communication is acknowledged and a method to handle a second incoming communications to a user device before the first incoming communication is acknowledged by the user. Such methods remove limitations on existing techniques by allowing users to select between pending and new incoming calls. In some embodiments, calls not selected by the users are placed on hold or routed to voicemail.

Handling incoming communication during communication set up

Systems and methods are described herein for recharging prepaid accounts within a telecommunications provider, such as a network carrier, using information provided by postpaid account subscribers. For example, the systems and methods facilitate the receipt of instructions from mobile devices associated with postpaid accounts. Upon receipt of the messages, the systems and methods (such as systems within a charging system of the network carrier or provider) identify intended or recipient mobile devices associated with prepaid accounts. Once identified, the systems and methods recharge the prepaid accounts, based on the instructions received from the postpaid account mobile devices.

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Bellevue, WA, United States of America

Karthik Chandrasekaran