Subscribers database proofing using a checksum in a telecommunications system

• US 20020177439A1
• Filed: 05/23/2001
• Published: 11/28/2002
• Est. Priority Date: 05/23/2001
• Status: Active Grant

• Current Assignee: Unwired Planet LLC (JP Morgan Chase & Co)
• Original Assignee: Telefonaktiebolaget LM Ericsson
• Inventors: Hansson, Rolf Elis Gustaf, Karlsson, Bernt
• Granted Patent: US 7,058,402 B2
• Time in Patent Office: Days
• US Class Current: 455/433
• CPC Class Codes: H04W 24/02 Arrangements for optimising operational condition

Abstract

The present invention is a method and system for updating location information of mobile stations. A mobile station moves from an area controlled by a first mobile services switching center (MSC) to an area controlled by a second MSC. The mobile station then registers with the second MSC, and, in response, the mobile station is added to a second MSC database. The second MSC recalculates a second MSC checksum to include the newly registered mobile station. Next, the HLR sends an HLR checksum to the second MSC. The second MSC compares the HLR checksum and the second MSC checksum. If the checksums are equal, then the second MSC sends the location registration signal to the mobile station. If the checksums are unequal, then the second MSC sends an error signal to the HLR, and also sets the second MSC database equal to a previous correct database. Next, the HLR sends all logged erasures to the second MSC. The second MSC then appropriately subtracts and adds each erased and newly registered mobile station to the database of the second MSC and recalculates the second MSC checksum until both checksums are equal.

Claims

1. A method in a second mobile services switching center for updating location information of a mobile station when said mobile station has moved from an area controlled by a first mobile services switching center to an area controlled by a second mobile services switching center, said method comprising:

adding said mobile station to a second mobile services switching center database in response to said mobile station registering with said second mobile services switching center;

calculating a second mobile services switching center checksum so as to include the said mobile station;

sending a home location register checksum to said second mobile services switching center from a home location register;

comparing said home location register checksum and said second mobile services switching center checksum; and

sending a location registration signal from said second mobile services switching center to said mobile station.

2. The method as recited in claim 1, wherein said step of comparing said home location register checksum and said second mobile services switching center checksum further comprises the additional steps of:

sending an error signal from said second mobile services switching center to said home location register when said home location register checksum and said second mobile services switching center checksum are not equal;

setting said second mobile services switching center database equal to a previous correct database when said home location register checksum and said second mobile services switching center checksum are not equal;

sending all logged mobile stations that have been erased from said home location register to said second mobile services switching center after receiving said error signal at said home location register from said second mobile services switching center; and

subtracting each erased mobile station and adding each newly registered mobile station identities to said previous correct database;

appropriately adding and subtracting each of said mobile station identities until said home location register checksum and said second mobile services switching center checksum are equal.

3. A method in an first mobile services switching center for updating location information of a mobile station, said method comprising:

sending a home location register checksum from a home location register to said first mobile services switching center;

subtracting said mobile station from a first mobile services switching center database;

recalculating a first mobile services switching center checksum to account for the subtracted mobile station;

sending an erasure acknowledge signal from said first mobile services switching center to said home location register; and

comparing said first mobile services switching center checksum to said home location register checksum.

4. The method of claim 3, wherein said step of comparing said first mobile services switching center checksum to said home location register checksum further comprises the additional steps of:

sending a negative acknowledge signal from said first mobile services switching center to said home location register when said home location register checksum and said first mobile services switching center checksum are not equal;

setting said first mobile services switching center database equal to a previous correct database when said home location register checksum and said first mobile services switching center checksum are not equal;

sending all logged mobile stations that have been erased from said home location register to said first mobile services switching center after receiving said error signal at said home location register from said first mobile services switching center;

subtracting each erased mobile station and adding each newly registered mobile station to said previous correct database;

appropriately adding and subtracting each of said mobile stations until said home location register checksum and said first mobile services switching center checksum are equal;

erasing the mobile stations that are resent in said logged erasures; and

stopping said sending of a negative acknowledge signal from said first mobile services switching center to said home location register when said first mobile services switching center checksum and said home location register checksum are equal.

5. A system for updating location information of a mobile station in a second mobile services switching center when said mobile station moves from an area controlled by a first mobile services switching center to an area controlled by a second mobile services switching center, said system comprising:

a first mobile services switching center for communicating with said mobile station and comprising;

a compare checksum procedure; and

a means for calculating a checksum stored in said first mobile services switching center;

a second mobile services switching center for communicating with said mobile station and comprising;

a compare checksum procedure; and

a means for calculating a checksum stored in said second mobile services switching center; and

a home location register for providing data to a plurality of mobile services switching centers.