US 12,267,911 B2
Deterministic PLMN selection during disaster roaming
Sudeep Manithara Vamanan, Munich (DE); Haijing Hu, Cupertino, CA (US); and Vivek G. Gupta, Cupertino, CA (US)
Assigned to APPLE INC., Cupertino, CA (US)
Filed by APPLE INC., Cupertino, CA (US)
Filed on Jul. 6, 2022, as Appl. No. 17/810,891.
Claims priority of provisional application 63/203,946, filed on Aug. 5, 2021.
Prior Publication US 2023/0043617 A1, Feb. 9, 2023
Int. Cl. H04W 8/12 (2009.01); H04W 60/04 (2009.01); H04W 84/04 (2009.01)
CPC H04W 8/12 (2013.01) [H04W 60/04 (2013.01); H04W 84/042 (2013.01)] 20 Claims
OG exemplary drawing
 
1. A method for a user equipment (UE) to perform public land mobile network (PLMN) selection for disaster roaming, the method comprising:
determining a disaster condition at a first PLMN, wherein the UE is a subscriber of the first PLMN;
determining an availability of a second PLMN for the disaster roaming;
selecting the second PLMN and attempting registration on the second PLMN for the disaster roaming;
in response to attempting the registration on the second PLMN for the disaster roaming, receiving a registration reject message comprising a cause value corresponding to a registration failure for the disaster roaming on the second PLMN due to the disaster condition on the first PLMN;
waiting for a first period of time before again attempting to register for the disaster roaming on the second PLMN for the first PLMN with the disaster condition;
in response to the registration reject message, incrementing a disaster roaming registration failure counter;
if the disaster roaming registration failure counter has exceeded a threshold, attempting to register on a third PLMN for the disaster roaming due to the disaster condition on the first PLMN; and
if the disaster roaming registration failure counter has not exceeded the threshold, waiting for a second period of time before attempting to register on the second PLMN for the disaster roaming due to another disaster condition on a fourth PLMN.