If we have national roaming, the UE which operator will select?
Is there any specific criteria or priority?
When roaming, a UE obtains services from a VPLMN other than its HPLMN.
For example, the UE may obtain services from a PLMN in another country (an international roaming area).
When the UE with the roaming service moves out of the coverage area of its HPLMN, the UE can obtain services from another PLMN according to the PLMN information stored on the USIM.
The operator determines whether roaming is allowed for a UE.
After the UE registers with a VPLMN by roaming, it periodically searches for its HPLMN and attempts to return to it.
The time interval between consecutive searches for the HPLMN is defined by the operator and stored on the USIM.
SIM has priority of operators built in.
It follows that order.
As i know, the UE will select the best coverage operator.
From my own experience there is strict priority and UEs follows that.
Only checks next operator if goes out of coverage in one.