The use of mobile communication systems through which to communicate both voice and non-voice data is increasingly pervasive throughout modern society. Successive generations of mobile communication systems have been developed and deployed. Each successive generation of communication systems has, in general, provided improved, and increased numbers of types of, communication services. For instance, an exemplary, second-generation cellular communication system that provides for code division communication techniques is referred to as a CDMA (Code Division, Multiple-Access) 1× communication system. A CDMA 1× communication system provides for both voice and data communication services. A successor system, referred to as EVDO (Evolution-Data Optimized) also provides for data communication services, but provides for the communication of data at significantly higher data throughput rates.
Backward compatibility is sometimes provided in successor-generation communication systems. That is to say, a mobile station operable in a successor-communication system is sometimes also operable in a corresponding, prior-generation communication system. For instance, a mobile station operable to communicate in a communication system that provides for EVDO sometimes also is constructed to be capable of operation in a CDMA 1× communication system. Generally, due to the communication advantages of a successor-generation network, communications are preferred to be carried out by way of the successor-generation system, if available. If communications are available with the prior-generation communication system but not with the successor-generation system, then communications are effectuable with the prior-generation system due to the backward compatibility of the mobile station.
The coverage areas of the communication networks of different communication systems, such as prior-generation and successor-generation communication systems of the same technology types, are regularly overlaid, or partially overlaid, upon one another. A mobile station, as a result, is sometimes positioned at a location within the coverage areas of two or more communication systems, permitting selection to be made of with which of the available communication systems through which to communicate. And, due to the mobility of the mobile station, the mobile station is subsequently repositionable elsewhere, such as at a location encompassed by the coverage area of the networks of a different number of communication systems. Additionally, a coverage area, such as a cellular coverage area, is not constant, but, instead, is variable, dependent upon, e.g., radio frequency conditions. Such variation in coverage area is sometimes referred to as cell breathing.
Selection of which communication system through which to communicate, therefore, cannot be made based merely upon the location of the mobile station. Analysis of the radio frequency characteristics associated with the available communication systems is required. However, particularly when the mobile station is positioned close to a boundary area at which the cell breathing effects are most noticeable, the selection of communication system through which to communicate is particularly difficult. Existing manners by which to make selection generally do not adequately take into account the uncertainty associated with the radio frequency, communication conditions of a communication system.
An improved manner of making selection of whether to permit communication of a mobile station with a communication system is therefore required.
It is in light of this background information related to communications in a radio communication system that the significant improvements of the present invention have evolved.