Call processing system

A call processing system for handling a call comprising a signaling interface configured to receive an initial address message wherein the initial address message identifies a calling party number, a processing system configured to process the calling party number to determine if the calling party number is in a first format accepted by a routing system and modify the initial address message if the calling party number is in a second format not accepted by the routing system, and the signaling interface further configured to transmit the modified initial address message to the routing system.

RELATED APPLICATIONS

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FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

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MICROFICHE APPENDIX

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BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention is related to the communications field, and in particular, to call processing systems and methods.

2. Description of the Prior Art

Mobile communications carriers typical handle calls connected from a mobile carrier network to destinations located on other networks such as the public switched telephone network (PSTN). To connect such a call destined for the PSTN, a mobile carrier routes the call from a mobile switch of their mobile network to a domestic switch of the PSTN. For example, the mobile carrier could route the call to a class 4 switch of the PSTN such as the DMS-250 offered by Nortel Networks, Inc.

During call setup, the mobile switch transmits call signaling to the domestic switch for call processing. The call signaling indicates the calling party number for the mobile phone which is used by the domestic switch to determine whether or not to connect the call and how to connect the call. For instance, the domestic switch might reject the call if the calling party number (CPN) indicates a customer that has delinquent bills. However, a problem arises when the CPN adheres to a format incompatible with a format recognized by the domestic switch therefore precluding the domestic switch from conducting call processing based on the CPN. For example, the DMS-250 class 4 switch recognizes CPNs that adhere to the North American Dialing Plan (NADP). If the CPN does not fit the NADP, the DMS-250 class 4 switch rejects the call.

Mobile carriers desire to provide international roaming services to customers, but these customers have calling party numbers that adhere to international formats and not the NADP. Thus, when the mobile carrier switch attempts to connect an international roaming call to the PSTN, the domestic switch of the PSTN does not recognize the international format of the calling party number and cannot conduct call processing based on the CPN. Lacking the ability to process the CPN, the domestic switch rejects the call.

SUMMARY OF THE INVENTION

An embodiment of the invention includes a call processing system for handling a call comprising a signaling interface configured to receive an initial address message wherein the initial address message identifies a calling party number, a processing system configured to process the calling party number to determine if the calling party number is in a first format accepted by a routing system and modify the initial address message if the calling party number is in a second format not accepted by the routing system, and the signaling interface further configured to transmit the modified initial address message to the routing system.

In some embodiments of the invention, the routing system comprises a switch of a public switched telephone network (PSTN).

In some embodiments of the invention, the signaling interface receives the initial address message from a mobile carrier switch.

In some embodiments of the invention, the processing system is configured to determine if a field of the initial address message is populated and populate the field if the field is not populated.

In some embodiments of the invention, the field comprises a charge number field and the charge number field is populated with a charge number.

In some embodiments of the invention, the field comprises an originating line identification field and the originating line identification field is populated with an originating line identification number.

In some embodiments of the invention, the routing system is configured to receive the modified initial address message and allow the call based on the charge number.

In some embodiments of the invention, the routing system is configured to receive the modified initial address message and allow the call based on the originating line identification number.

In some embodiments of the invention, the first format is compatible with the North American Dialing Plan.

In some embodiments of the invention, the call processing system comprises a service control point (SCP).

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

First Embodiment Configuration and Operation

FIG. 1illustrates communication system100in an embodiment of the invention. Communication system100includes call processing system110connected to call routing system120. Call processing system could comprise a service control point (SCP) or other similar call processing equipment. Call routing system120could comprise a switch of the Public Switched Telephone Network (PSTN).

FIG. 2illustrates a flowchart describing the operation of communication system100in an embodiment of the invention. Call processing system110receives a message (Step200) and determines if the message is an initial address message (IAM) (Step210). If the message is not an IAM, call processing system110transmits the message for any remaining call processing (Step240) to routing system120. If the message is an IAM, call processing system110determines if the calling party number stored in the calling party number field of the IAM is in an acceptable format (Step220). If the format is acceptable, call processing system110transmits the message for any remaining call processing (Step240) to routing system120. If the format is not acceptable, call processing system110modifies the IAM (Step230). Next, call processing system110transmits the message for any remaining call processing (Step240) to routing system120.

Second Embodiment Configuration and Operations

FIG. 3illustrates communication system300in an embodiment of the invention. Communication system300includes call origination system310, call routing system320, call processing system330, and destination system340. Call processing system330is coupled to call origination system310and call routing system320. Call routing system320is connected to call origination system310and destination system340. Call origination system310could comprise a switch of the public switched telephone network (PSTN) or a mobile telephone switch operated by a wireless telecommunications carrier. Call routing system320comprises a collection of switches in the PSTN. Call processing system330comprises a service control point (SCP). Destination system340could comprise a switch, a mobile switch, a destination device such as a telephone, or a combination of such elements.

FIG. 4illustrates the operation of communication system300in an embodiment of the invention. Call origination system310transmits an initial address message (IAM) for a call to call routing system320. Call routing system320receives the IAM and sends the IAM to call processing system330. Call processing system330receives the IAM and processes the calling number field in the IAM to determine if the calling party number fits an acceptable format. If the calling party does not fit an acceptable format, call processing system330modifies the IAM. The IAM is modified based upon requirements of call routing system320to allow call connection through routing system320to destination system340. Call processing system330sends the modified IAM to call routing system320. The call is then connected from call origination system310to destination system340.

FIG. 5illustrates the operation of communication system300in an embodiment of the invention. Call origination system310transmits an initial address message (IAM) for a call to call processing system330. Call processing system330receives the IAM and processes the calling number field in the IAM to determine if the calling party number fits an acceptable format. If the calling party does not fit an acceptable format, call processing system330modifies the IAM. The IAM is modified based upon requirements of call routing system320to allow call connection through routing system320to destination system340. Call processing system330sends the modified IAM to call routing system320. The call is then connected from call origination system310to destination system340.

Third Embodiment Configuration and Operations

FIG. 6illustrates communication system600in an embodiment of the invention. Communication system600includes cell phone610, mobile carrier switch621, signal transfer point (STP)625, international roaming service provider system (IRSP)630, class 4 switch622, local switch624, and called party640. Cell phone610connects to mobile carrier switch621by a wireless connection. Class 4 switch622is connected to mobile carrier switch621and local switch624. STP625is connected to mobile carrier switch621, class 4 switch622, and IRSP630. STP625could also be connected to local switch624although that is not shown for clarity. IRSP630comprises an SCP. Called party640is connected to local switch624. Local switch624could comprise a central office switch, a central branch exchange (CBX), or any other similar type of switching equipment that connects called party640to the PSTN.

FIG. 7illustrates the operation of communication system600in an embodiment of the invention. In this embodiment, cell phone610is a foreign device roaming on a domestic network. Cell phone610sends a called number to mobile carrier switch621. Mobile carrier switch621typically sends an integrated services digital network user part (ISUP) message to STP625. STP625receives the ISUP message and passes the ISUP message to IRSP630. STP625passes the ISUP message to IRSP630based upon a determination that the OPC included in the ISUP message indicates that the ISUP message originated from mobile carrier switch621. Alternatively, STP625could pass the ISUP message to IRSP630based upon a determination that destination point code (DPC) included in the ISUP message indicates IRSP630as the destination for the ISUP message.

IRSP receives the ISUP message and passes any ISUP message that is not an IAM to class 4 switch622without any further processing. If the ISUP message is an IAM, IRSP630inspects the calling number in the IAM to determine if the calling number fits an acceptable format. If the calling number fits the appropriate format, IRSP630sends the unmodified IAM to class 4 switch622. If the calling number does not fit the appropriate format, IRSP630modifies the IAM. The IAM is modified based upon requirements of DSM250switch622. If the calling number fits an international format, IRSP630modifies the IAM so that class 4 switch622will connect the call. Class 4 switch622receives the modified IAM, proceeds with call setup messaging, and connects the call from cell phone610to called party640.

FIG. 8illustrates a flowchart that describes the operation of communication system600in an embodiment of the invention. Mobile carrier621passes an ISUP message to STP625. STP625passes the ISUP message to ISRP for SS7 ISUP stack processing (Step800). IRSP determines if the message is an IAM (Step810). If the ISUP message is not an IAM, IRSP updates the DPC and OPC (Step880), completes any remaining SS7 ISUP stack processing (Step890), and transmits the ISUP message to class 4 switch625(Step899).

If the ISUP message is an IAM, IRSP630determines if the calling party number (CPN) in the calling party field of the IAM is in an international format (Step820). If the CPN is not in an international format, IRSP updates the destination point code (DPC) and origination point code (OPC) (Step880), completes any remaining SS7 ISUP stack processing (Step890), and transmits the ISUP message to class 4 switch625(Step899). If the CPN is in an international format, IRSP next determines if the charge number field of the IAM is populated (Step830).

If the charge number field is populated, IRSP updates the DPC and OPC (Step880), completes any remaining SS7 ISUP stack processing (Step890), and transmits the ISUP message to class 4 switch625(Step899). If the charge number field is not populated, IRSP630creates a copy of the IAM message (Step840) and populates the charge number field with a pseudo charge number (Step850).

Next, IRSP630determines if the originating line information (OLI) field is populated (Step860). If the OLI field is populated, IRSP updates the DPC and OPC (Step880), completes any remaining SS7 ISUP stack processing (Step890), and transmits the ISUP message to class 4 switch625(Step899). If the OLI field is not populated, IRSP630populates the OLI field with a pseudo OLI (Step870), updates the DPC and OPC (Step880), completes any remaining SS7 ISUP stack processing (Step890), and transmits the ISUP message to class 4 switch625(Step899).

Class 4 switch625receives the ISUP message and connects the call. Advantageously, adding information to the charge number field and the OLI field to a 15 digit CPN allows class 4 switch625to complete the call to an end location with the calling party number intact. Class 4 switch625will connect the call even though the calling party number fits an international format because a populated charge number field indicates the call can be charged to a customer. Similarly, a populated OLI field indicates to class 4 switch625a line from which calls should be connected. The call could terminate within the PSTN or to an international location. If the call terminates to an international location, the class 4 switch625would connect the call to a DMS300switch for transport to an international telecommunication network. A DMS300switch could also support the operation described byFIG. 7.

FIG. 9illustrates call processing system900in an embodiment of the invention. Call processing system900includes signaling interface920, processing system930, storage system940, and software950. Storage system940stores software950. Processing system930is linked to signaling interface920. Call processing system900could be comprised of a programmed general-purpose computer, although those skilled in the art will appreciate that programmable or special purpose circuitry and equipment may be used. Call processing system900may use a client server architecture where operations are distributed among a server system and client devices that together comprise elements920-950.

Signaling interface920could comprise a network interface card, modem, port, or some other communication device. Signaling interface920may be distributed among multiple communication devices. Processing system930could comprise a computer microprocessor, logic circuit, or some other processing device. Processing system930may be distributed among multiple processing devices. Storage system940could comprise a disk, tape, integrated circuit, server, or some other memory device. Storage system940may be distributed among multiple memory devices.

Processing system930retrieves and executes software950from storage system940. Software950may comprise an operating system, utilities, drivers, networking software, and other software typically loaded onto a general-purpose computer. Software950could also comprise an application program, firmware, or some other form of machine-readable processing instructions. When executed by the processing system930, software950directs processing system930to operate as described for call processing system110,330, and IRSP630.