US 11,743,704 B2
Emergency service fallback based on user equipment capability
Suresh Thanneeru, Redmond, WA (US); Christopher H. Joul, Bellevue, WA (US); Boris Antsev, Bothell, WA (US); and William Michael Hooker, Seattle, WA (US)
Assigned to T-Mobile USA, Inc., Bellevue, WA (US)
Filed by T-Mobile USA, Inc., Bellevue, WA (US)
Filed on Feb. 9, 2021, as Appl. No. 17/171,969.
Claims priority of provisional application 62/975,149, filed on Feb. 11, 2020.
Prior Publication US 2021/0250745 A1, Aug. 12, 2021
Int. Cl. H04W 4/90 (2018.01); H04W 4/029 (2018.01); H04W 8/22 (2009.01); H04W 60/00 (2009.01); H04W 84/04 (2009.01)
CPC H04W 4/90 (2018.02) [H04W 4/029 (2018.02); H04W 8/22 (2013.01); H04W 60/00 (2013.01); H04W 84/042 (2013.01)] 17 Claims
OG exemplary drawing
 
1. A method performed by a first telecommunication network, the method comprising:
receiving, from a user equipment (UE), a network registration message comprising a UE voice capability indicator;
determining, during a network registration process and based on the UE voice capability indicator, that the UE does not support emergency calls via the first telecommunication network;
transmitting, during the network registration process and to the UE in response to the network registration message, an emergency call instruction that configures the UE to use second telecommunication network emergency fallback procedures,
the emergency call instruction causing the UE to include an emergency service fallback indicator in a service request for an emergency call sent by the UE to the first telecommunication network;
receiving the service request from the UE;
in response to receiving the service request:
refraining from performing call setup operations associated with the emergency call via the first telecommunication network; and
steering the UE directly to a second telecommunication network for the emergency call, based on the emergency service fallback indicator in the service request,
the first telecommunication network is a fifth generation (5G) telecommunication network, and
the second telecommunication network is a Long-Term Evolution (LTE) telecommunication network.