US 12,143,870 B2
Security handling of 5GS to EPC reselection
Dominique Francois Bressanelli, Eschborn (DE); Osama Lotfallah, San Diego, CA (US); Cogol Tina, Mission Viejo, CA (US); Abhishek Bhatnagar, San Diego, CA (US); Vitaly Drapkin, San Diego, CA (US); and Lenaig Genevieve Chaponniere, La Jolla, CA (US)
Assigned to QUALCOMM Incorporated, San Diego, CA (US)
Filed by QUALCOMM Incorporated, San Diego, CA (US)
Filed on May 11, 2022, as Appl. No. 17/662,978.
Claims priority of provisional application 63/187,784, filed on May 12, 2021.
Prior Publication US 2022/0369176 A1, Nov. 17, 2022
Int. Cl. H04W 60/04 (2009.01); H04W 36/00 (2009.01)
CPC H04W 36/0038 (2013.01) [H04W 36/0022 (2013.01)] 23 Claims
OG exemplary drawing
 
1. An apparatus for wireless communication at a user equipment (UE), comprising:
a memory; and
at least one processor coupled to the memory and configured to:
transmit, to a first network entity, a first tracking area update (TAU) request, the first TAU request encoded using a first security context associated with a first radio access technology (RAT), the first TAU request being integrity protected using a first uplink count based on the first security context, and the first TAU request including a first set of information comprising a mapped Evolved Packet System (EPS) Globally Unique Temporary UE Identity (EPS GUTI), an EPS key set identifier (eKSI), and a non-access stratum Message Authentication Code (NAS-MAC);
transmit, to the first network entity in response to a radio link failure, a second TAU request, the second TAU request including the first set of information, wherein the first set of information comprises the EPS GUTI, the eKSI, and the NAS-MAC included in the first TAU request, the second TAU request being integrity protected using a second uplink count;
derive a mapped security context based on the first security context and at least one of the first uplink count or the second uplink count; and
communicate with the first network entity based on the mapped security context.