ROAMING SERVICE FOR MOBILE COMMUNICATIONS

摘要

A method of automatically establishing a roaming service for a mobile telephone, that includes a pre-programmed SIM card, performs a Location Update in the following order. 1. Registered Public Land Mobile Network ("RPLMN"), i.e. the last registered network as stored in the SIM directory EFLOCI (EF6F7E). 2. Home PLMN ("HPLMN"). 3. PLMNs contained in a "PLMN Selector" data field based on the "Operator List". 4. User - defined preferred PLMN. 5. Other PLMNs with received signal level above a predetermined strength in random order; and 6. All other PLMNs in order of descending signal strength.