Invention Grant
- Patent Title: System and method for determining establishment causes for emergency sessions
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Application No.: US16729051Application Date: 2019-12-27
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Publication No.: US11310288B2Publication Date: 2022-04-19
- Inventor: Chen Ho Chin , Richard C. Burbidge
- Applicant: BlackBerry Limited
- Applicant Address: CA Waterloo
- Assignee: BlackBerry Limited
- Current Assignee: BlackBerry Limited
- Current Assignee Address: CA Waterloo
- Agency: Fish & Richardson P.C.
- Main IPC: H04W4/90
- IPC: H04W4/90 ; H04L65/1016 ; H04W76/50 ; H04W76/27 ; H04W76/12

Abstract:
A method for initiating a Packet Switched emergency call using a user equipment (UE) is presented. The UE includes a plurality of protocol layers. The plurality of protocol layers including an IMS sublayer, a non-access stratum (NAS) layer and an access stratum (AS) layer. The method includes generating an ATTACH REQUEST using the UE. The ATTACH REQUEST has an attach type. The method includes retrieving the attach type of the ATTACH REQUEST using the NAS layer of the UE, and generating an RRC CONNECTION REQUEST. The RRC CONNECTION REQUEST includes an RRC establishment cause based upon the attach type of the attach request.
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