Telecommunications – Radiotelephone system – Zoned or cellular telephone system
Reexamination Certificate
1996-11-04
2001-03-27
Wolfe, Willis R. (Department: 3747)
Telecommunications
Radiotelephone system
Zoned or cellular telephone system
C455S429000, C455S440000
Reexamination Certificate
active
06208857
ABSTRACT:
BACKGROUND OF THE INVENTION
I. Field of the Invention
The invention generally relates to mobile telephone systems and in particular to service provider selection in a mobile telephone system.
II. Description of the Related Art
Satellite-based mobile telecommunications systems are being developed that allow a mobile communications subscriber unit such as a mobile telephone to be used almost anywhere in the world. In one system, illustrated in
FIG. 1
, a fleet of low earth orbit satellites are used along with a set of ground base stations
10
called “gateways”. Signals are transmitted from a subscriber unit
12
to satellites
14
(shown as a single satellite for ease of drawing), then relayed down to gateway
10
for routing to one of a set of local service providers, generally denoted
16
, which provide an interconnection to local land line telephone networks or other communication networks operated by a service provider. Depending upon the nature of the communication, the signals are ultimately routed to, for example, a telephone connected to the land line network, or to a mobile telephone perhaps operating in another part of the world covered by a different gateway, or perhaps to computer system. The signals may encode voice communications such as telephone conversations or data communications such as, for example, facsimile transmissions, Internet connection signals, etc. The subscriber unit
12
may be a hand-held mobile telephone, a mobile telephone mounted in a boat, train or airplane, a laptop computer, a personal data assistant or any other suitable communications unit provided with the proper equipment for communicating with the gateway via the satellite fleet.
A single gateway may handle all telecommunications traffic within an area covering as much as 2000 by 3000 kilometers.
FIG. 2
illustrates an exemplary coverage area
18
for a gateway
20
operating in Europe. As can be seen, the coverage area encompasses many countries. Each country typically has one or more service providers. Depending upon the implementation, each service provider may operate only within one country or perhaps only within a portion of one country. Such restrictions may result from physical limitations on the capability of the service provider system or from contractual or other legal constraints. For example, even though operationally capable of doing so, a service provider in France may not be contractually and/or legally allowed to handle mobile communications for a subscriber unit operating in Italy and vice versa. Hence, for subscriber units in France (such as exemplary unit
22
), the gateway may need to route communications through a French service provider such as TE.SA.M.; whereas, for subscriber units in Italy, the gateway may need to route communications through an Italian service provider such as Finmeccanica. Further, as represented by arrow
24
, subscriber units may move from one country to another. Even within a single country the gateway may need to selectively route communications to different service providers depending upon the location of the subscriber unit within the country. Moreover, the operator of the subscriber unit may be contractually obligated to use certain service providers in certain locations or may be subject to other legal constraints. In addition to any contractual limitations that may prevent telephone connections from the subscriber unit from being connected to particular service providers, the user of the subscriber unit may simply have certain preferences regarding which services provider to employ.
For these and other reasons, it may be desirable for the gateway to be able to reliably coordinate access among numerous service providers and among numerous mobile telephone users over a large geographical area. Heretofore, no adequate system has been developed for that purpose, particularly one which takes into account user preferences. Aspects of the present invention are directed toward providing such a system.
SUMMARY OF THE INVENTION
In accordance with one aspect of the invention, a system is provided for selecting a service provider based upon the location of a subscriber unit or perhaps upon service provider preferences provided by the subscriber unit, or both. The service provider may be alternatively selected based upon the altitude, velocity or speed of the subscriber unit or upon the time of day or date or upon a combination thereof. The system, which may be part of a gateway ground base station, is employed in connection with a mobile communication system or other wireless communication system, such as a satellite-based communication system, having two or more service providers. The system selects one of the service providers for use in receiving signals from, and for routing signals to, a subscriber unit such as a mobile telephone. To this end, the system may interconnect a local Public Switched Telephone Network (PSTN) to the subscriber unit via the selected service provider. Selection of the service provider is performed, for example, as part of set up operations for a telephone connection initiated by the subscriber unit or terminated at the subscriber unit, or as part of a system registration access procedure initiated by the subscriber unit.
In an implementation wherein selection is based upon location, different service providers may handle communications for subscriber units in different geographical areas. Accordingly, the means for selecting one of the service providers may operate to identify the geographical area in which the subscriber unit is disposed and selects a service provider available for handling communications from subscriber units in that geographical area. The geographical areas of the service providers may overlap. Hence, two or more service providers may be available in any particular area. The different geographical areas may be different countries or different parts of the same country. The availability of a service provider to handle mobile communications from the geographical area of the subscriber unit may be constrained, in part, by operational factors or by contractual or other legal factors.
The location of the subscriber unit may be determined in accordance with any one of a variety of techniques. For satellite-based systems, the location may be determined based upon time differences and frequency shifts of signals received by the satellites from the subscriber unit. Alternatively, the subscriber unit may be provided with some means for determining its own location, such as a Global Positioning System (GPS) unit. In one implementation, the location of the subscriber unit is approximated with a degree of confidence and the service provider is selected based, in part, upon the degree of confidence.
The location of the subscriber unit, once determined, is applied to a table, or other means, listing all of the service providers available for handling mobile communications from that location area. The table takes into account the aforementioned constraints, such as contractual or other legal constraints. Based upon the location of the subscriber unit, the table may identify that one service provider is available, no service providers are available or more than one service provider is available for handling communications from the subscriber unit.
If more than one service provider is available, the system operates to select one of the service providers based upon a preference provided by the subscriber unit. The preference may be provided as part of a subscriber unit system access message (used in a subscriber unit origination, response to an incoming call, a system registration access, etc.), or it may be in response to a query by the system. The preference specified by the subscriber unit may be the identification of the last service provider to which the subscriber unit was registered. In the case where the system queries the subscriber unit for the preference, the system sets a timer upon issuing the request, and if the timer elapses before receiving a response, the system terminates further action with
Agre Daniel H.
Quick Roy F.
Spartz Michael K.
Ogrod Gregory D.
Qualcomm Incorporated
Thibault Thomas M.
Wadsworth Phillip R.
Wolfe Willis R.
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