WO2000054484A1

WO2000054484A1 - System and method for local number portability routing improvement

Info

Publication number: WO2000054484A1
Application number: PCT/SE2000/000377
Authority: WO
Inventors: Raul Davalos
Original assignee: Telefonaktiebolaget Lm Ericsson (Publ)
Priority date: 1999-03-05
Filing date: 2000-02-25
Publication date: 2000-09-14
Also published as: AU3686200A

Abstract

A system and method for routing a call from a non-Local Number Portability (non-LNP) telecommunications network calling party subscriber to a ported party located within an LNP telecommunications network is disclosed. The system comprises a non-LNP area Calling Exchange CE (470) and an LNP area Donor Exchange DE (340) associated with the ported party. The system may include a Service Control Point SCP (465) associated with the LNP area DE. The method comprises sending a call setup origination message (390) from a non-LNP area Calling Exchange (400, 410) to the LNP area Donor Exchange associated with the ported party; obtaining the Location Routing Number from the Service Control Point associated with the LNP area DE; sending a reroute message (540) from the LNP area DE to the non-LNP area CE; and establishing a trunk (270) connection between the non-LNP area CE and an LNP area Recipient Exchange RE (350) associated with the ported party which is not required to pass through the LNP area DE or some other LNP area exchange, as the reroute message is interpreted by the non-LNP area CE. Typically, the directory number or Mobile Identification Number associated with the ported party is used to identify the ported party to the LNP area DE.

Description

SYSTEM AND METHOD FOR LOCAL NUMBER PORTABILITY ROUTING IMPROVEMENT

BACKGROUND OF THE INVENTION Technical Field

This invention relates generally to Local Number Portability (LNP) call routing procedures, and more particularly, to a method for improving LNP call routing when a non-LNP area calling party attempts to reach a ported party that is part of an LNP network.

History of Related Art

With the advent of telecommunications systems, users are no longer physically bound to fixed locations for network communications. In addition, using the added capabilities of roaming and interoffice handoffs, mobile subscribers may travel between multiple Public Land Mobile Networks utilizing the same telephone number and the same mobile station to originate outgoing calls and to receive incoming calls. Thus, a subscriber may access telecommunications services from multiple locations using multiple service providers with all incurred fees charged to a single subscription. Further, calling parties do not necessarily have to know where any particular subscriber is physically located in order to establish a call connection. Data signals between a Visitor Location Register (VLR) and a Home Location Register (HLR) automatically update and store subscriber information, and more particularly, mobile subscriber location information, which enables the network to reroute incoming calls to the appropriate Mobile Switching Center (MSC) serving the roaming mobile subscriber. Regardless of which MSC is currently serving the roaming mobile station, the VLR associated with the serving MSC communicates with the HLR assigned to the mobile station to retrieve the requisite subscriber data, including subscriber feature data and billing data, enabling uniform mobile services for the mobile station.

However, with an increasingly mobile society and a global business environment, many subscribers wish to change their home geographic location on a long-term basis, without giving up their established fixed location directory number or Mobile Identification Number (MIN), also referred to as the phone number dialed by the calling party. Local Number Portability (LNP), widely established throughout the United States, has been implemented as a solution to this problem.

LNP enables the user to change from his original service provider to a different provider without having to change the number dialed by the calling party.

For this to happen, the original service provider becomes a "donor switch," and the new provider becomes the "recipient switch," and the user becomes the "ported party. " By using an intelligent network (IN) configuration, calls dialed to the subscriber's phone number that are received at the donor switch are automatically routed toward the recipient switch and the ported party.

Turning now to Fig. 1, there is shown a prior art LNP-network nodal operations diagram. Consider a set of interconnected nodes contained entirely within an LNP area 10, with no nodes located in the non-LNP area 20, namely, LNP-only network 30 . That is, the Calling Exchange (CE) 60, the Donor Exchange (DE) 40 and the Recipient Exchange (RE) 50 all utilize the LNP protocols , and are all located within the LNP area 10. For example, the CE 60 may be located in Dallas, Texas, the DE 40 may be located in New York City, New York, and the Recipient Exchange may be located in Los Angeles, California.

The first step in placing a call from the calling party 70 to the ported party 80, associated with CE 60 and RE 50, respectively, occurs when the calling party

70 originates a call connection by dialing a telephone directory number associated with the ported party 80 (which may be the MIN associated with a roaming party). A call set-up origination message 90, usually communicated using the Signaling System 7 (SS7) protocol, and containing the directory number of the ported party 80, is sent to the DE 40, in accord with the numbering plan in effect for the geographic area in which the DE 40 is located. For illustration purposes, all of the signaling messages described as a part of the inventive method are assumed to be sent and received using the SS7 protocol. However, other protocols well known in the art may be substituted for the SS7 protocol when carrying out the inventive method. In addition, Donor and Recipient exchanges may be referred to as gateway mobile service centers to which the ported party 80 previously subscribed, and currently subscribes, respectively.

The DE 40 queries its local Service Control Point (SCP) 165 by way of the SCP query message 100 to get the Location Routing Number (LRN), which in this case points to the RE 50 (i.e. , the exchange to which the ported party has been ported), and the SCP 165 returns the LRN of the ported party 80 to the DE 40 by way of the SCP response message 110. The LRN is routed onward toward the CE 60 by way of DE LRN response message 120. Of course, the LRN may also be routed directly from the SCP 165 to the CE 60 by way of the SCP LRN response message 130, and in fact, the SCP 165 may be set up so that trigger flags in the signaling message from the CE 60 operate to retrieve the ported party 80 LRN directly from the SCP 165 (without any operation of the DE 40).

Once the LRN of the ported party 80 is communicated to the CE 60, the call is forwarded to the RE 50 by way of the CE LRN request message 140. The RE 50 then determines that the ported party 80 current location may be serviced directly by the RE 50, and the request message 140 is accompanied by a request for resources from the RE 50. In return, the RE 50 sends the RE resource allocation response 150 to the CE 60 and a trunk 160 connection is established. At this time, voice communications between the calling party 70 and the ported party 80 may commence. Thus, when ported party communications occur entirely within an LNP area 10, routing occurs directly between the CE 60 and the RE 50. No extraneous trunk connections, such as between the CE 60 and the DE 40, for example, are required.

A problem occurs, however, when the calling party 70 is located in a non-LNP area 20. Turning now to Fig. 2, there is shown a prior art nodal network operations diagram, wherein the process of completing a call from a non-LNP area calling party 370 , located in a non-LNP area 20, to a ported party 80 located in an LNP area 10, is illustrated.

As described previously, the non-LNP area calling party 370 originates a call connection by dialing a directory number (which may be a MIN) associated with the ported party 80. The call set-up origination message 90 containing the directory number of the ported party 80 is sent from the non-LNP area CE 170 to the LNP area DE 40, a signaling transfer point (STP), or some other LNP area exchange which may access the SCP 165 directly from the non-LNP area CE 170 in accord with the numbering plan in effect for the geographic area in which the LNP area DE

40 is located. Assuming the LNP area DE 40 is accessed, the LNP area DE 40 then queries its local Service Control Point (SCP) 165 by way of the SCP query message 100 to get the Location Routing Number (LRN) which points to the LNP area RE 50, and the SCP 165 returns the LRN of the ported party 80 to the LNP area DE 40 by way of the SCP response message 110.

At this point in the progress of the call connection process, the situation changes somewhat from that described above. In this case, even though the LNP area DE 40 has the LRN of the ported party 80, the LRN, along with the directory number for the ported party 80 is sent to the LNP area RE 50 by way of a LNP DE LRN request message 180. The LNP RE resource allocation response 190 is sent from the LNP area RE 50 to the LNP area DE 40, and a first trunk 200 is established. To complete the call connection process, the LNP DE resource request message 210 is sent from the LNP area DE 40 to the non-LNP area CE 170, and a second trunk 220 is established (assuming again that the LNP area RE 50 services the ported party 80 directly). At this time, voice communications between the non-LNP area calling party 370 and the ported party 80 may commence. This process is necessary because the non-LNP area CE 170 can not directly receive the LRN to re-route the call, so the call will always be routed through an LNP area exchange or node prior to reaching the LNP RE 50 along a trunk connection path similar to, or identical to, the trunk connection path 215. As can be seen, the attempt by a non-LNP area calling party 370 to contact an LNP area 10 ported party 80 is routed by way of two trunks, namely, the first trunk 200 and the second trunk 220. With respect to distance and resource utilization, this solution is inefficient. However, this problem exists whenever a call is made from a non-LNP area 20 to an LNP area 10. If the originating switch or exchange is not part of the LNP network, then the call is never routed directly to the recipient switch from the originating switch (unless the ported party is currently served by a RE which is located along the trunk connection path to the DE). While inefficient routing for parties located entirely within the LNP system has been eliminated, such inefficiency exists whenever calls from a non-LNP subscriber are made to an LNP area subscriber that has been ported to a different location.

Therefore, what is needed is an improved method of routing calls from a non-LNP area subscriber to an LNP ported party which has been ported to a different home location. Such a method should not only reduce the distance traversed during routing, if possible, but also act to minimize the number of trunks established between the non-LNP area CE 170 and the LNP area RE 50, associated with the ported roaming party 80.

SUMMARY OF THE INVENTION A system for routing a call from a non-Local Number Portability (non-LNP) telecommunications network calling party subscriber to a ported party located within a LNP telecommunications network includes a non-LNP area CE, and a LNP area Donor Exchange (DE) associated with the ported party. The non-LNP area CE is adapted to send a call setup origination message to the ported party using a first number, which may be the mobile identification number, or a telephone directory number, identifying the ported party. Upon determining that the non-LNP area CE is not within the LNP network, the DE is adapted to send a reroute message including a second number (usually the Location Routing Number) identifying a Recipient Exchange (RE) associated with the ported party back to the non-LNP area CE. The system may also include a Service Control Point (SCP) associated with the DE, the SCP being adapted to receive a query message from the DE including the first number, and further adapted to respond with a message including the second number back to the DE. A method for routing a call from a non-Local Number Portability (non-LNP) telecommunications network calling party subscriber to a ported party within a LNP telecommunications network allows a trunk to be established directly from the calling party to the ported party Recipient Exchange (RE), without necessarily having to route the call through the Donor Exchange (DE) or some other exchange or node in the LNP area. This is accomplished by querying the DE associated with the ported party, after an origination message is received from the non-LNP area Calling Exchange (CE) to establish a connection. The DE sends a query message to its SCP, containing the directory number or MIN of the ported party. The SCP response message, which includes the LRN of the RE associated with the ported party, is sent to the LNP area DE. Once the LNP area DE determines that the non-LNP area CE is outside of the LNP service area, a reroute message which determines the trunk connection path is then sent from the DE to the non-LNP CE, directing the non-LNP CE to route the call directly to the LNP area RE. The non-LNP area CE sends a resource allocation request message to the LNP area RE once it determines the new route, so that a trunk connection path can be established directly between the non-LNP CE and the LNP area RE.

BRIEF DESCRIPTION OF THE DRAWINGS

A more complete understanding of the structure and operation of the present invention may be had by reference to the following detailed description when taken in conjunction with the accompanying drawings, wherein:

Fig. 1 , previously described, is a prior art nodal network operations diagram illustrating communications between a calling party and a ported party which occur entirely within an LNP area; Fig. 2, previously described, is a prior art nodal network operations diagram illustrating communications between a non-LNP area calling party and a LNP area ported party; and

Fig. 3 is a nodal network operations diagram illustrating the method of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

Turning now to Fig. 3, a nodal network operations diagram illustrating the method of the present invention can be seen. In this case, the call setup origination message 390 (containing the directory number or MIN of the LNP area ported party 380) from the non-LNP area CE 470 to the LNP area DE 340 is sent after the non-LNP area calling party 370 dials the directory number or MIN of the LNP area ported party 380. It should be noted that the non-LNP area calling party 370 is located in a non-LNP area 320, while the LNP area ported party 380, which has been ported from the LNP area DE 340 to the LNP area RE 350, is located in the LNP area 310. After the LNP area DE 340 receives the call set-up origination message 390, the SCP query message 400 is sent to the SCP 465 from the LNP area DE 340. In return, the SCP response message 410, containing the LRN of the ported party 380 (which points to the LNP area RE 350), is received by the LNP area DE 340 from the SCP 465. At this point in the process of completing a call from the non-LNP area calling party 370 to the LNP area ported party 380, a reroute message 540 is sent from the LNP area DE 340 to the non-LNP area CE 470, along with the LRN of the LNP area ported party 380. The CE resource allocation request 550 is sent to the LNP area RE 350 by the non-LNP area CE 470 once the new route is determined by the non-LNP area CE 470, and the RE resource allocation response message 560 is returned to the non-LNP CE 470. Once the RE resource allocation response message 560 is received by the non-LNP area CE 470 , the non-LNP to LNP trunk 270, which may not pass through the LNP area DE 340, can be established. At this time, voice communication between the non-LNP area calling party 370 and the LNP area ported party 380 may commence. Thus, using the method of the present invention, non-LNP area callers attempting to contact LNP area subscribers that have been ported to other exchanges within an LNP area may now complete telephone calls without necessarily routing through the donor exchange, or some other LNP area exchange or node. Thus the trunk connection path 275 between the non-LNP area CE 470 and the LNP area RE 350 is now determined by the non-LNP area CE 470 after the reroute message is received, and does not require routing via an extraneous exchange within the LNP area. While the trunk connection path 275 may indeed be routed through the LNP area DE 340, or some other LNP area exchange or node, this will now only occur as determined by the reroute message as interpreted by the CE, and not as determined by the first-encountered LNP area exchange or node.

While the commonly used terms MIN and LRN have been used to describe identification numbers for various entities within the networks, other data can be used for identification, and can be generically characterized as a first number, and a second number, respectively. Further, the non-LNP area CE 470 may comprise a mobile service center, or a local exchange serving a wire line calling party terminal, as may the LNP area RE 350. In fact, the non-LNP area CE 470, the LNP area DE 340 , and the LNP area RE 350 may also be characterized as a non-LNP area node, a first LNP area node, and a second LNP area node, respectively. As mentioned above, the first LNP area node may also comprise an STP or some other exchange located in the LNP area, including an LNP area node that is adapted to serve as a gateway between the non-LNP area 320 and the LNP area 310.

Although the invention has been described with reference to specific embodiments, this description is not meant to be construed in a limited sense. The various modifications of the disclosed embodiments, as well as alternative embodiments of the invention, will become apparent to persons skilled in the art upon reference to the description of the invention. It is, therefore, contemplated that the appended claims will cover such modifications that fall within the scope of the invention, or their equivalents.

Claims

WHAT IS CLAIMED IS:

1. A method for routing a call from a non-Local Number Portability (non-LNP) telecommunications network calling party subscriber to a ported party located within a LNP telecommunications network comprising the steps of: sending an origination message from a non-LNP area node to a first

LNP area node so as to establish a call connection with a ported LNP-area party, said origination message having a first number identifying the ported party; sending a reroute message including a second number identifying a second LNP area node associated with the ported party from the first LNP area node to the non-LNP area node; sending a resource allocation message including the first and second numbers from the non-LNP area node to the second LNP area node; sending a resource allocation response message from the second LNP area node to the non-LNP area node in response to the resource allocation message; and establishing a trunk connection path between the non-LNP area node and the second LNP area node determined by the reroute message as interpreted by the non-LNP area node.

2. The method of claim 1 wherein the non-LNP area node is a non-LNP area Calling Exchange.

3. The method of claim 1 wherein the first LNP area node is a LNP area Donor Exchange or another LNP area node adapted to serve as a gateway between the non-LNP area and the LNP area.

4. The method of claim 1 wherein the second LNP area node is a LNP area Recipient Exchange.

5. The method of claim 1 wherein said first number includes a directory number associated with the ported party.

6. The method of claim 1 wherein said first number includes a Mobile Identification Number (MIN) associated with the ported party.

7. The method of claim 1 wherein the second number includes a Location Routing Number (LRN) associated with the second LNP area node.

8. The method of claim 1 , further comprising the step of sending a message including the first number from the calling party to the non-LNP area node .

9. The method of Claim 1, further comprising the steps of: sending a Service Control Point (SCP) query message including the first number from the first LNP area node to a SCP associated with the first LNP area node; and receiving a SCP response message by the first LNP area node including a second number identifying the second LNP area node in response to the SCP query message.

10. The method of claim 9 wherein the step of receiving a SCP response message further comprises the step of sending a reroute message including the second number from the first LNP area node to the non-LNP area node.

11. A system for routing a call from a non-Local Number Portability (non-LNP) telecommunications network calling party subscriber to a ported party located within a LNP telecommunications network comprising: a non-LNP area node adapted to send a call setup origination message to establish a call connection with a ported LNP area party having a first number identifying the ported party; and a first LNP area node associated with the ported party adapted to send a reroute message including a second number identifying a second LNP area node associated with the ported party to the non-LNP area node, wherein the non-LNP area node uses the reroute message to determine a trunk connection path between the non-LNP area node and the second LNP area node.

12. The system of claim 11 wherein the non-LNP area node is a non-LNP area Calling Exchange.

13. The system of claim 11 wherein the first LNP area node is a LNP area Donor Exchange.

14. The system of claim 11 wherein the second LNP area node is a LNP area Recipient Exchange.

15. The system of Claim 11 , further comprising a Service Control Point

(SCP) associated with the first LNP area node, the SCP adapted to receive a query message from the first LNP area node including the first number, and further adapted to send a SCP response message including the second number identifying the second LNP area node.

16. The system of Claim 11 wherein the second number includes a Location Routing Number (LRN) associated with the second LNP area node.

17. The system of Claim 11 , wherein the first LNP area node is adapted to determine that the non-LNP area node is not located within the LNP telecommunications network.

18. The system of claim 11 wherein said first number includes a directory number associated with the ported party.

19. The system of claim 11 wherein said first number includes a Mobile Identification Number (MIN) associated with the ported party.