Tracking systems occasionally use radio communications to discover the whereabouts of mobile units. One example of such a tracking system is used by a communication network which provides communication services through mobile radio transceivers. Radio communication messages, which are transparent to radio users, keep a central controller informed of the locations of the mobile transceivers receiving communication services through the network.
Location data are extremely valuable to a communication network. Knowledge of mobile unit location allows the network to most advantageously route communications through nodes of the network. In addition, it allows the network to conform to diverse rules and procedures which may be imposed by diverse political entities within whose jurisdictions the network may operate. For example, one jurisdiction may permit network operations only within a first set of frequencies while an adjacent jurisdiction may permit network operations only within a second set of frequencies. In addition, different tariffs or taxes may apply to communication services utilized by mobile units operating in different jurisdictions.
The more accurate the location data, the better. More accurate data allow the network to better ascertain when mobile units cross from one jurisdiction into another. However, costs generally increase in proportion to the accuracy of the location data, and an intense need to keep costs as low as possible and revenues as high as possible exists. One cost, which is of particular concern, is the amount of communication resources which are consumed in maintaining current location data. As more resources are consumed in maintaining current location data, fewer resources are available for use by communication service subscribers and for generating revenues. In addition, mobile units are often battery operated, and an excessive quantity of communications leads to an excessive use of available battery power.