Patent ID: 9713080
Date: 2017-07-18
CPC Classifications: H04W

Claim:
1. A communication device of handling a public land mobile network (PLMN) selection in a roaming country, comprising: a storage unit, for storing instructions of: determining that the communication device is roaming; selecting a preferred roaming PLMN with a preferred roaming PLMN ID to camp on, if the preferred roaming PLMN ID stored in a subscriber identity module (SIM) of the communication device; and selecting a first roaming PLMN with a first roaming PLMN ID to camp on, if the preferred roaming PLMN ID is not stored in the SIM of the communication device, or the communication device does not find the preferred roaming PLMN and the first roaming PLMN ID is associated with a first home PLMN ID of the communication device; searching and registering to a second roaming PLMN in the roaming country, wherein a second roaming PLMN ID of the second roaming PLMN is not stored in the communication device or the communication device fails to register to the first roaming PLMN; associating the second roaming PLMN ID with the first home PLMN ID; storing an association between the second roaming PLMN ID and the first home PLMN ID in the communication device; receiving a third roaming PLMN ID of a third roaming PLMN, a second home PLMN ID and an association between the third roaming PLMN ID and the second home PLMN ID from a server; storing the third roaming PLMN ID, the second home PLMN ID and the association between the third roaming PLMN ID and the second home PLMN ID in the communication device; and a processing means, coupled to the storage unit, configured to execute the instructions stored in the storage unit.