Methods and apparatus for supporting optimum call routing in a cellular telecommunications system

• US 6,871,072 B1
• Filed: 09/23/1997
• Issued: 03/22/2005
• Est. Priority Date: 09/23/1997
• Status: Expired due to Fees

• Current Assignee: Nokia Mobile Phones UK Limited (Nokia Corporation)
• Original Assignee: Nokia Corporation
• Inventors: Meche, Paul S
• Primary Examiner(s): Nguyen, Lee
• Application Number:
  US08/933,911
• Time in Patent Office: 2,737 Days
• Field of Search: 455/445, 4554321-4323, 455/433, 455/435.1, 455/458, 455/459, 455/460, 455/461
• US Class Current: 455/445
• CPC Class Codes: H04W 8/06 Registration at serving network Location Register, VLR or user mobility server

Abstract

Disclosed are methods for operating a wireless terminal or mobile station in a wireless telecommunications system. A first method includes steps of (a) transmitting a telephone number that includes an identifier for specifying that a user of the mobile station is calling a second mobile station that is believed to be roaming in a current serving system; (b) receiving the telephone number in the current serving system, typically at a mobile switching center (MSC); (c) detecting the presence of the identifier and, in response, determining if the telephone number is one that is stored in a Visitor Location Register (VLR) of the current serving system. If yes, the method includes a step (d) of paging the second mobile station in the current serving system. In one embodiment the step of transmitting includes an initial step of entering an identifier character into a memory of the mobile station, followed by the telephone number of the second mobile station. In a second embodiment the step of transmitting includes an initial step of entering the telephone number of the second mobile station into the memory of the mobile station, followed by the identifier character. In a second method the MSC automatically determines if a received telephone number is one that is associated with a potential roamer. If yes, the MSC checks to see if the telephone number is present in the MSC'"'"'s VLR. If yes, the mobile station associated with the telephone number is paged.

Claims

1. A method for operating a wireless telecommunications system, comprising the steps of:

providing a telephone number and an identifier for specifying that a caller is calling a mobile station that is believed to be roaming in a particular serving system, where providing the telephone number includes an initial step of entering the telephone number of the called mobile station into a memory of a calling mobile station, followed by an identifier character;

receiving said telephone number and said identifier in the serving system;

detecting the presence of said identifier and, in response, without interrogating another serving system, determining if said telephone number is one that is stored in a Visitor Location Register of said serving system; and

if yes, paging said mobile station in said serving system.

2. A cellular telecommunications system, comprising:

a first mobile station for transmitting a telephone number that includes an identifier specifying that a user of the first mobile station is calling a second mobile station which is believed to be roaming in a current serving system; and

a first base station and mobile switching center (MSC) for receiving the telephone number in the current serving system, said MSC including a controller that detects a presence of the identifier and, in response, determines without interrogating another mobile switching center if the telephone number is one that is stored in a Visitor Location Register of the MSC and, if yes, pages the second mobile station using the first or a second base station, wherein said first mobile station includes a keypad for entering the telephone number of the second mobile station into a memory of the mobile station, followed by an identifier character.

3. A method for operating a wireless telecommunications system, comprising the steps of:

transmitting a telephone number that includes an appended identifier for specifying that a first mobile station is calling a second mobile station that may be roaming in a particular serving system;

receiving the telephone number in the serving system;

detecting the presence of the appended identifier and, in response, without interrogating another serving system, examining a Visitor Location Register of the serving system to determine if the telephone number is one that is associated with a valid roaming mobile station; and

if the telephone number is determined to be one that is associated with a valid roaming mobile station, paging the second mobile station in the serving system, else, performing one of completing the call using a conventional call completion technique or sending a message to the first mobile station for indicating that the telephone number is not one that is associated with a valid roaming mobile station.

4. A method as in claim 3, wherein the step of sending a message includes a further step of terminating the call.

5. A method for operating a wireless telecommunications system, comprising the steps of:

providing a telephone number of a called party;

receiving said telephone number in a serving system, the received telephone number having an appended identifier;

in response to detecting the presence of the appended identifier, determining if said telephone number is for a mobile station potentially roaming in the serving system, without interrogating another serving system;

if yes, determining if said telephone number is stored in a Visitor Location Register of the serving system; and

if yes, paging the mobile station in the serving system.

6. A cellular telecommunications system, comprising:

a first mobile station for transmitting a telephone number that comprises an appended identifier; and

a first base station and mobile switching center (MSC) which receives said telephone number in a serving system, said MSC including a controller which determines based on said appended identifier if said telephone number is associated with a mobile station potentially roaming in said serving system and, without interrogating another mobile switching center, determines if the telephone number is one that is stored in a Visitor Location Register of the MSC and, if yes, pages the roaming mobile station using said first or a second base station.

7. A method for operating a wireless telecommunications system, comprising the steps of:

at a first mobile switching center, receiving a telephone number having an appended identifier, wherein said telephone number is registered in a home location register of a second mobile switching center;

in response to the presence of said appended identifier, checking a visitor location register of said first mobile switching center to determine if said telephone number is a valid roaming number under said first mobile switching center; and

paging a roaming mobile station identified with said telephone number;

wherein said home location register of said second mobile switching center is not accessed.

8. A switching center for mobile cellular telecommunications, comprising:

a visitor location register;

a home location register; and

a controller that controls message switching to at least one base station;

wherein when a received telephone number having an appended pre-translation identifier is received, said controller looks for said telephone number in said visitor location register without communicating with another mobile switching center, and if said telephone number is found in said visitor location register said controller pages a roaming mobile station associated with said telephone number using said base station.