Backward update strategy for location management

• US 7,171,219 B2
• Filed: 11/15/2004
• Issued: 01/30/2007
• Est. Priority Date: 05/21/2004
• Status: Expired due to Fees

• Current Assignee: BenQ Corporation (Qisda Corporation)
• Original Assignee: BenQ Corporation (Qisda Corporation)
• Inventors: Hu, Chih-Lin
• Primary Examiner(s): Kincaid, Lester G.
• Assistant Examiner(s): Zewari, Sayed T.
• Application Number:
  US10/989,068
• Publication Number:
  US 20050261005A1
• Time in Patent Office: 806 Days
• Field of Search: 4554561-4566, 455/414.2, 455/415, 455/440
• US Class Current: 455/456.5
• CPC Class Codes: H04W 4/14 Short messaging services, e.g. short message services [SMS] or unstructured supplementary service data [USSD]
• CPC Class Codes: H04W 8/04 Registration at HLR or HSS [Home Subscriber Server]
• CPC Class Codes: H04W 8/06 Registration at serving network Location Register, VLR or user mobility server
• CPC Class Codes: H04W 8/12 between location registers or mobility servers
• CPC Class Codes: H04W 8/20 Transfer of user or subscriber data
• CPC Class Codes: H04W 8/22 Processing or transfer of terminal data, e.g. status or physical capabilities
• CPC Class Codes: H04W 92/24 between backbone network devices

Abstract

A backward location update method for location management in wireless PCNs is provided. The VLR employs an intelligent micro procedure to determine different types of location update requests and performs a backward location update in the HLR only when required by call or short message delivery. Accordingly, the VLR avoids unnecessary location updates in the HLR.

Claims

1. A backward location update method for location management in a personal communication service (PCS) network, comprising:

detecting movement of a mobile station (MS) in the PCS network from a first location area (LA) to a second LA;

determining a location update type of the MS according to an update message received by a first visitor location register (VLR), wherein the location update type comprises an inter-LA or inter-MSC movement denoting the first and second LAs are connected to the same mobile switch center (MSC) or different MSCs respectively;

updating a record stored in the first VLR corresponding to the MS, wherein the record is updated according to addresses of the second LA and a current MSC and a flag in the record is set if the location update type is an inter-MSC movement; and

preventing instantaneous notification to a home location register (HLR) of the change of the record until a mobile station roaming number (MSRN) interrogation corresponding to the MS is received by the first VLR or when a record stored in the HLR is expired.

2. The backward location update method according to claim 1, further comprising:

receiving the MSRN interrogation corresponding to the MS by the first VLR;

checking if the flag in the record stored in the first VLR is set; and

backward updating a record stored in the HLR corresponding to the MS by sending a backward location update message from the first VLR to the HLR if the flag is set.

3. The backward location update method according to claim 2, further comprising resetting the flag after updating the record stored in the HLR.

4. The backward location update method according to claim 2, wherein the backward location update message comprises international mobile subscriber identity (IMSI) of the MS, addresses of the current MSC, and the first VLR.

5. The backward location update method according to claim 1, wherein the location update type further comprises an inter-VLR movement denoting that the first and second LAs belong to MSCs connected to different VLRs, and the second LAs corresponding to a second VLR.

6. The backward location update method according to claim 5, while the location update type is an inter-VLR movement, the method further comprises:

dispatching an identification message from the second VLR to the first VLR;

responding with the record stored in the first VLR corresponding to the MS to the second VLR;

creating a record stored in the second VLR for the MS;

forwarding a location update message to the HLR;

updating the record stored in the HLR corresponding to the MS upon receiving the location update message; and

instructing the first VLR to delete the record stored in the first VLR corresponding to the MS.

7. The backward location update method according to claim 1, further comprising:

forwarding a short message from a short message system gateway MSC (SMS-GMSC) to the MSC by using an MSC number derived from interrogation of the HLR;

sending a request message from the MSC to the first VLR;

checking the flag in the record stored in the first VLR corresponding to the MS upon receiving the request message;

updating the location information of the MS in the HLR if the flag is set; and

initiating a retransmission of the message after updating the HLR.

8. The backward location update method according to claim 7, further comprising sending a failure report to the SMS-GMSC and the HLR while the VLR updating the location information of the MS in the HLR, wherein the failure report comprises an erroneous case generated by the VLR to indicate a short message transfer attempt failing.

9. The backward location update method according to claim 1, wherein the flag in the record stored in the first VLR comprises one bit.

10. The backward location update method according to claim 1, wherein the MSRN interrogation is initiated by a local exchange or a gateway mobile switch center (GMSC) interrogating the HLR for routing information of the MS.