Patent ID: 7962135

Claim:
In a mobile station including a preferred roaming list, a method for an efficient selection system for registration/acquisition of wireless communications systems that avoids time consuming acquisition of a signal that takes up to about 20 seconds, comprising: a) maintaining a list of unusable wireless communications systems, each entry of a wireless communications system in the list of unusable wireless communications systems including a system identifier and corresponding avoidance criterion that is equal to a current time plus an avoidance duration time from a look-up table that includes an entry for each of a plurality of communications failures and corresponding avoidance durations for not using the wireless communications system, wherein at least one of said unusable wireless communications systems is included on the preferred roaming list; b) selecting a wireless communications system from the preferred roaming list of wireless communications systems in accordance with a predetermined system acquisition sequence, each entry of a wireless communications system in the preferred roaming list including a system identifier; c) determining whether the selected wireless communications system from the preferred roaming list is a useable wireless communications system or an unusable wireless communications system; by using system avoidance data and corresponding avoidance criteria to identify unusable systems; adding systems to system avoidance data in response to a communications failure, and removing systems from the system avoidance data when correspondence avoidance criteria is no longer satisfied; d) acquiring and registering with the selected wireless communications system when the selected wireless communications system is determined to be a useable wireless communications system; and e) repeating the step of selecting, before attempting to acquire and register with the selected wireless communications system, when the selected wireless communications system is determined to be an unusable wireless communications system, wherein said system identifier for the selected wireless communications system includes a SID/NID pair that uniquely identifies a wireless communications system that matches a system identifier in the list of unusable wireless communications systems to determine when avoidance criterion corresponding to the system identifier in the list of unusable wireless communications systems is satisfied.