Method for computing current time on a cellular mobile system

• US 5,920,824 A
• Filed: 09/02/1997
• Issued: 07/06/1999
• Est. Priority Date: 03/08/1995
• Status: Expired due to Fees

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Jenness, Robert V., Pitts, Michael A., Beatty, Dana L.
• Primary Examiner(s): Bost, Dwayne D.
• Assistant Examiner(s): MAUNG, NAY AUNG
• Application Number:
  US08/923,548
• Time in Patent Office: 672 Days
• Field of Search: 455/418, 455/419, 455/422, 455/425, 455/432, 455/550, 455/552, 455/556, 455/566, 368/21, 368/22, 368/47
• US Class Current: 455/425
• CPC Class Codes: H04W 4/02 Services making use of location information
• CPC Class Codes: H04W 4/029 Location-based management or tracking services
• CPC Class Codes: H04W 88/02 Terminal devices

Abstract

A method is disclosed for computing the local time and date of a mobile computer, when a user has traveled to a time zone different from his or her home time zone is disclosed. A system identification number is received through a cellular transceiver which is associated with an antenna. The system identification number is received by the mobile computer through a cellular modem. A database is provided within the mobile computer listing all of the system identification numbers throughout the North American Cellular Network. The database also provides the geographic location and time zone for each system identification number. Also listed in the database is information whether daylight savings time is observed in the geographic location associated with the system identification number. The computer, upon receiving a system identification number, searches the database for the same identification number. If a match is found, the computer obtains the relevant information and calculates the current local system time from the home system time previously stored in the computer. If no match is found, the user has the option to update the database, to include the new system identification number.

Claims

1. A method for computing a local system time for a mobile computer, when a user has traveled to a time zone different from his or her home time zone, said mobile computer having a home system time and home time zone entered in said mobile computer, said mobile computer also having a database stored within, said database containing a list of system identification numbers, said database also providing time zone information for each system identification number listed, said method comprising the steps of:

(a) querying and storing the current mode of operation of a subscriber unit;

(b) changing the mode of said subscriber unit to cellular mode, if the current mode of operation is other than cellular;

(c) receiving a connected cellsite'"'"'s system information, including a system identification number;

(d) deciphering the system identification number from the system information;

(e) searching the list of system identification numbers stored within the database for the connected system identification number to obtain relevant time zone information;

(f) querying the mobile computer to obtain the system time; and

(g) selecting a matching system identification number from the database and calculating the local system time based on the entered home system time and the information received from the matching system identification number if a match for the connected system identification number is stored within the database; and

if a matching system identification number for the connected system identification number is not stored in the database, entering the connected system identification number and its relevant time zone information to the list of system identification numbers and calculating the local system time based on the entered home system time and the time zone information of the connected system identification number.

2. The method of claim 1 further including the step of updating the home system time by setting the calculated local system time as a new home system time.

3. The method of claim 2 further including the step of displaying the calculated local system time.

4. The method of claim 3 further including the steps of obtaining SID geographic location information from said database and displaying the SID geographic location on said screen.

5. The method of claim 2 wherein the step of calculating the local system time comprises either subtracting or adding to the home system time based on the information received from the database to determine the local time.

6. A method of computing a local time for a mobile computer when the mobile computer is moved from its home area, the mobile computer having a home time and a home time zone stored within, the mobile computer being cellular capable, wherein data signals are communicated between the mobile computer and a base station, said mobile computer having stored therein a database containing a plurality of system identification data, each system identification associated with either a system carrier A or a system carrier B, each system identification data in said database including time zone information, said mobile computer being operable in an idle mode, wherein the mobile computer receives control messages including system identification data and system carrier information from the base station, the method comprising the steps of:

(a) transmitting to said mobile computer, from the base station serving the service cell in which said mobile computer is located, the base station'"'"'s system information, including a system identification code and a system carrier information;

(b) deciphering the system identification code and the system carrier information from the system information received from the base station;

(c) determining if a matching system identification code and associated system carrier information are stored within the database; and

(d) selecting the matching system identification code and computing the local time of the mobile computer based on the stored home time and stored home time zone and from the information stored in the database associated with the matching system identification code and system carrier information; and

if the deciphered system identification code is not previously listed in said database, entering the deciphered system identification code and associated system carrier information to the database and computing the local time of the mobile computer based on the stored home time and stored home time zone and from the deciphered system identification code and associated system carrier information.

7. The method of claim 6 further including the step of storing the computed local time within the mobile computer.

8. The method of claim 6 further including the step of displaying the computed local time on a screen associated with the mobile computer.

9. The method of claim 7 further including the step of displaying the computed local time on a screen associated with the mobile computer.

10. An apparatus for use in a cellular capable mobile computer wherein data signals are communicated between the mobile computer and a base station, said mobile computer having stored therein a database containing a plurality of system identification data, each system identification associated with either a system carrier A or a system carrier B, each system identification data in said database including time zone information, said mobile computer being operable in an idle mode, wherein the mobile computer receives control messages including system identification data and system carrier information from the base station, said apparatus comprising:

means for receiving control messages from the base station;

means for deciphering the system identification data and the system carrier information from the received control message;

system identification data and system carrier detecting means associated with said mobile computer for detecting if the system identification data and system carrier information deciphered from the control messages matches a system identification data and associated carrier information stored within the database;

means for selecting a matched system identification data from the database;

computing means for determining a second time based on a first time and time zone initially stored within the mobile computer, said computing means utilizing the time zone information stored within the database that is associated with the matched system identification data and system carrier information for computing the second time; and

means for updating the database to include the deciphered system identification code and associated system carrier information if the deciphered system identification code is not previously listed in said database.

11. A method for computing a second time for a mobile computer, when a user has traveled, with the mobile computer, from his or her based area, said mobile computer having a first time and first time zone stored within said mobile computer, said method comprising the steps of:

(a) obtaining system information from a cellular base station in the vicinity of the mobile computer, said system information including a System Identification Number (SID);

(b) obtaining said SID from the system information;

(c) looking up said SID in a database stored within said mobile computer for deriving SID time zone information; and

(d) selecting a matching SID from the database and computing the second time from the first time and first time zone stored within the mobile computer and the SID time zone information derived from the database; and

if a matching SID is not found in the database, entering the SID including a time zone information obtained from the cellular base station to the database and computing the second time from the first time and first time zone stored within the mobile computer and the SID time zone information.

12. The method of claim 11 further including the step of storing the computed second time within the mobile computer.

13. The method of claim 11 further including the step of displaying the computed second time on a screen associated with the mobile computer.

14. The method of claim 12 further including the step of displaying the computed second time on a screen associated with the mobile computer.

15. The method of claim 13 further including the steps of obtaining SID geographic location information from said database and displaying the SID geographic location on said screen.

16. The method of claim 11 further including the step of updating the first time by setting the computed second time as a new first time.