Home location register and method of routing calls to portable numbers in a radio telecommunications network

• US 6,226,517 B1
• Filed: 08/28/2000
• Issued: 05/01/2001
• Est. Priority Date: 10/07/1997
• Status: Expired due to Term

• Current Assignee: Telefonaktiebolaget LM Ericsson
• Original Assignee: Telefonaktiebolaget LM Ericsson
• Inventors: Bishai, Nadia, Britt, Margaret
• Primary Examiner(s): Chang, Vivian
• Assistant Examiner(s): NGUYEN, DUC M
• Application Number:
  US09/650,466
• Time in Patent Office: 246 Days
• Field of Search: 455/445, 455/433, 455/434, 455/435, 455/422, 455/423, 455/458, 455/461, 379/207, 379/219, 379/220, 379/221, 379/230
• US Class Current: 455/445
• CPC Class Codes: H04Q 3/005 Personal communication services, e.g. provisions for portability of subscriber numbers
• CPC Class Codes: H04W 8/28 Number portability ; Network address portability

Abstract

A home location register (HLR) and method of routing a call directed to a portable directory number in a radio telecommunications network. The network includes an originating mobile switching center (O-MSC) and a Number Portability Database (NPDB). The O-MSC first sends a Location Request (LOCREQ) message to the HLR requesting a routing number. The LOCREQ message includes a dialed directory number. The HLR determines whether a routing number is assigned to the dialed directory number. If not, the HLR sends a Number Portability Request (NPREQ) message to the NPDB and includes the dialed directory number. A location routing number (LRN) assigned to the dialed directory number is then retrieved from the NPDB and sent to the HLR. The HLR forwards the LRN to the O-MSC, which then routes the call to the LRN.

Claims

1. A method of routing a call directed to a portable directory number in a radio telecommunications network having an originating mobile switching center (O-MSC), a home location register (HLR), and a Number Portability Database (NPDB), said method comprising the steps of:

sending a first routing number request from the O-MSC to the HLR, said first routing number request including a dialed directory number;

determining in the HLR whether a routing number is assigned to the dialed directory number;

sending a second routing number request from the HLR to the NPDB upon determining that a routing number is not assigned to the dialed directory number in the HLR, said second routing number request including the dialed directory number;

retrieving from the NPDB, a location routing number (LRN) assigned to the dialed directory number;

sending the LRN from the NPDB to the HLR in a first response message;

sending the LRN from the HLR to the O-MSC in a second response message; and

routing the call to the LRN.

2. The method of routing a call directed to a portable directory number of claim 1 further comprising, upon determining in the HLR that a routing number is assigned to the dialed directory number, the step of sending the routing number from the HLR to the O-MSC.

3. A home location register (HLR) for providing a routing number to an originating mobile switching center (O-MSC) when an incoming call is directed to a portable directory number in a radio telecommunications network, said network including a Number Portability Database (NPDB) that stores a plurality of location routing numbers (LRNs), said HLR comprising:

a signaling mechanism that;

receives from the O-MSC, a first routing number request that includes a dialed directory number;

sends to the NPDB, a second routing number request that includes the dialed directory number;

receives from the NPDB, an LRN assigned to the dialed directory number in response to the second routing number request; and

sends to the O-MSC, the LRN in response to the first routing number request; and

means for determining whether a routing number is assigned to the dialed directory number, said routing number determining means directing the signaling mechanism to send the second routing number request to the NPDB upon determining that a routing number is not assigned to the dialed directory number.