Use of an audit message sent to mobile stations to confirm the location thereof

• US 5,247,698 A
• Filed: 02/26/1990
• Issued: 09/21/1993
• Est. Priority Date: 02/26/1990
• Status: Expired due to Term

• Current Assignee: Telefonaktiebolaget LM Ericsson
• Original Assignee: Telefonaktiebolaget LM Ericsson
• Inventors: Wong, Janice, Sawyer, Francois
• Primary Examiner(s): Eisenzopf, Reinhard J.
• Assistant Examiner(s): Faile, Andrew
• Application Number:
  US07/485,130
• Time in Patent Office: 1,303 Days
• Field of Search: 455/33, 455/34, 455/54, 455/56, 455/67-68, 379/59, 379/60, 379/63, 340/992, 340/993
• US Class Current: 455/435.1
• CPC Class Codes: H04W 60/00 Affiliation to network, e.g. registration; Terminating affiliation with the network, e.g. de-registration
• CPC Class Codes: H04W 60/06 De-registration or detaching
• CPC Class Codes: H04W 8/12 between location registers or mobility servers

Abstract

A mobile communications system includes at least one subscriber; a home exchange for the at least one subscriber; at least two exchanges, which may include the home exchange, that may be accessed by the at least one subscriber; and means for ensuring that the at least one subscriber has registered as being located within only one of the at least two exchanges. A method according to the teachings of the present invention includes the steps of cancelling all but the last registration when more than one registration is effected and correctly reestablishing mobile station registration and location data by sending an audit message from the exchanges in which a registration was cancelled to a mobile when the registration was cancelled within a predetermined period of time after being established.

Claims

1. A mobile communications system comprising:

at least one subscriber;

a home exchange for said at least one subscriber, said home exchange maintaining location data for said at least one subscriber;

at least two exchanges, one of which may be said home exchange, within which said at least one subscriber may be located; and

means for ensuring said at least one subscriber is registered as being located in only one of said at least two exchanges, wherein said means for ensuring said at least one subscriber is registered as being in only one of said at least two exchanges comprises;

means included with said at least one subscriber for registering as being located within either one of said at least two exchanges;

means included with said home exchange for determining whether said at least one subscriber is simultaneously registered as being located in more than one exchange, the occurrence of which is an erroneous indication of registration status; and

means for correcting the erroneous indication of registration status within said home exchange.

2. A system as recited in claim 1, wherein said means for correcting the erroneous indication of registration status within said home exchange comprises:

means for cancelling all but the last registration when said at least one subscriber is registered as being located in more than one exchange; and

means, triggered by a registration cancellation, for registration to be re-established by either one of said at least two exchanges in which said at least one subscriber is actually located.

3. A system as recited in claim 2, wherein said means triggered by a registration cancellation for registration to be re-established by an exchange in which said at least one subscriber is actually located comprises an audit message sent by each of said exchanges to a mobile whose registration was cancelled within a predetermined period after registration was established, and wherein a registration is re-established if and only if a response to said audit message is received by one of said exchanges.

4. A system as recited in claim 3 wherein said predetermined period is brief.

5. A system as recited in claim 4 wherein said predetermined period is on the order of 5 seconds.

6. A system as recited in claim 4, wherein said audit message is a page request.

7. A method of ensuring a mobile subscriber having a home exchange is registered as being located in only one exchange, said home exchange receiving location reports from exchanges in which said mobile subscriber may roam, comprising the steps of:

cancelling all but the last registration when more than one registration has been made because more than one exchange simultaneously reports said mobile subscriber to be located therein, said last registration becoming a retained registration; and

performing an auditing function in each exchange in which a registration was cancelled, wherein said auditing function creates a new registration that supercedes the retained, last registration if said mobile subscriber is actually located in an exchange in which a registration was cancelled.

8. A method as recited in claim 7, wherein said step of performing an auditing function comprises the steps of:

sending an audit message from the exchanges in which a registration was cancelled to said mobile station when said registration was cancelled within a predetermined period of time after said registration was established; and

using a response from said mobile station, or lack of such a response, to confirm the mobile station registration or to confirm cancellation of registration for said mobile station, respectively.

9. A method as recited in claim 8, wherein said audit message is a page request.

10. A radiotelephone exchange in a system of cooperating exchanges through which mobile subscribers may roam, each of said mobile subscribers having a home exchange, a mobile subscriber appropriately registered only in one exchange, said exchange corresponding to the one in which said mobile subscriber is physically located, said radiotelephone exchange comprising:

means for determining whether a time interval between registration of a mobile subscriber and cancellation of said registration by said mobile subscriber'"'"'s home exchange is less than a predetermined amount; and

means for auditing said mobile subscriber if said time interval between registration of said mobile subscriber and cancellation of said registration of said mobile subscriber by the mobile subscriber'"'"'s home exchange is less than said predetermined amount so as to be able to register said mobile.

11. An exchange as recited in claim 10, wherein said predetermined amount of time is on the order of five seconds.

12. An exchange as recited in claim 10, wherein said mobile subscriber has a mobile station, and wherein said means for auditing comprises means for sending a page request to said mobile station of said mobile subscriber.

13. A radiotelephone exchange having home subscribers in a system of cooperating exchanges which may be accessed by one or more of said home subscribers, said radiotelephone exchange comprising:

means for determining whether a home subscriber of said home subscribers is registered in more than one of said cooperating exchanges; and

means for cancelling all but the last of such multiple registrations in said cooperating exchanges upon determining such multiple registrations exist.