A METHOD FOR A RADIOTELEPHONE TO SCAN FOR HIGHER PRIORITY PUBLIC LAND MOBILE NETWORK

摘要

A method for a radiotelephone to scan for a higher priority (including home) public land mobile network (PLMN) without searching in all possible RATs and frequencies includes a first step of establishing an inclusive list of all frequencies in all radio access technologies (RATs) in use by the higher priority or home public land mobile network. A next step includes camping the radiotelephone on the higher priority or home PLMN. A next step includes obtaining the inclusive list from the establishing step by the camped radiotelephone from the higher priority or home PLMN. Afterwards, when the radiotelephone roams to a lower priority visited PLMN, it can begin scanning for the home (and higher priority) PLMN using only those frequencies from the inclusive list, thereby saving battery power.