SG178646A1 - Ctsp incoming call termination control - Google Patents

Abstract

A Mobile subscriber call forwards their mobile phone numbers to a local pilot number of a DID trunk group or trunk group eliminating the need to provide dedicated DID numbers for each subscriber wishing to use the service and the calls are automatically re-forwarded to a remote SIM card number purchased at the distant location by the subscriber eliminating inbound roaming charges to the mobile subscriber being called. The distant Call Termination Service Provider (CTSP) must determine the original number forwarded to the pilot number since there is no direct relationship between the DID selected by the pilot number and subscriber number. By inspecting the called number call processing databases POP to POP using known SS7 control channel commands of the type, MAP, TCAP or ISUP and combinations of such commands to ascertain the original call forwarded number and then mapping the original call forwarded number to the appropriate remote purchased SIM card by way of translation table setup by the provider of the remote SIM (CTSP) and sending that new termination number to the terminating switch so that the final leg of the call can be established to the purchased remote SIM card even though the caller dialed the callers original SIM card number eliminating the inbound roaming charge.

Description

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INTREGEN File No. GRP 05271001

CTSP INCOMING CALL TERMINATION CONTROL

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This is the first application filed for the present invention.

MICROFICHE APPENDIX

[0002] Not Applicable.

TECHNICAL FIELD

The present disclosure relates to a system and method of managing of inbound voice calls intended for a mobile subscriber who is outside the subscriber home location (roaming) allowing the subscriber to receive Inbound voice calls on the subscribers mobile device without incurring inbound mobile roaming charges.

BACKGROUND OF THE INVENTION

Wireless devices connect to switching or IP networks without the use of wires and can transfer both voice and data information and interconnect to other wireless and land line devices by interconnecting wirelessly to a mobile network provider that interconnects the devices. Wireless devices usually connect to the mobile network provider by sending . signals in an analog or digital format to a radio tower often called a cell tower which in turn connects to a switching center usually referred to as a MSC or Mobile Switching Center by interconnection to radio towers, a common example is . the Mobile Phone or Cell Phone.

There are many examples of wireless devices (WD) and many formats such as mobile telephone devices commonly referred to as mobile phones, cellular phones, satellite phones, SmartPhones, PDA’s, tablets, of which these are just a few examples and wireless devices that are not considered telephones but capable of making wireless telephone calls such as laptops. desktop computers, inboard automobile computers.

Herein the term wireless device (WD) or mobile device (MD) means any device with wireless connectivity capabilities.

These wireless devices interoperate with a variety of network technologies such as TDMA, CDAM, UMTS, EDGE, HSCD,

GPRS,AMPS, and many other network technologies that are constantly evolving and designed to improve the interconnection efficiency of the mobile device with the mobile network provider. These examples are only some of the technologies that may be deployed to interconnect the mobile device to the mobile network operator.

A subscriber is the owner or user of a wireless device who enters into a contract with a local mobile network operator for access rights to the operator’s network which enables the wireless device to interconnect with other wireless devices locally and around the world. :

When a subscriber makes a voice call using a WD to another subscriber, we refer to the calling subscriber as the Calling

Party or CP and the PSTN number associated with CP as Calling Party Number CPN.

The local mobile network operator that the subscriber has a contractual arrangement with for right to access the local network is called the “Home Location Network” (HLN } and a HLN associated database called a HLR or “Home Location

Registry” and the geographic area that the HLN covers is the Home Location or HL. When a subscribers turns on their WD the subscriber connects to the HLN 20 through a series of interconnected cellular radio towers and the HLN 20 identifies the wireless device and checks with the HLR 20c to ensure that the WD 4 has a valid subscription to operate on the HLN

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. 20. If the subscriber is outside the range of the HLN 20 and connects to another mobile network operator's network they are considered “roaming” and any mobile network other than the Home Location Network 20 is a “Roaming Location

Network” (RLN) 35 and mobile device connectivity to a RLN 35 incurs an additional per usage charge called a roaming fee. Roaming fees can be much higher that the total monthly subscription rates hence there is a desire by subscribers to reduce roaming fees.

In order to interconnect with other wireless devices or land lines a common PSTN number scheme is deployed and the subscriber is provided a PSTN number by their HLN 20 operator and embedded in the HLN 20 operator provided subscriber SIM card along with the Subscriber Identity information. A PSTN number is any number that is supported by the PSTN 22 and can be interconnected by any device connected to the PSTN 22. Herein we will refer to a Mobile Phone

PSTN number embedded in the Mobile SIM card provided by the HLN operator as a Home Number or HN and a remote

SIM number embedded PSTN number provided by a RLN operator as the Roaming Number or RN. When referring to an

RN in regards to CLI ISUP message content, the RN is often referred to in the industry as the Redirecting Number. For the purpose of this document when we refer to the Redirecting Number we will use the word Redirecting Number or acronym ReN and when we mean Roaming Number we will use the acronym RN.

A condition in which roaming fees can be charged is when inbound calls to a subscriber are forwarded to the roaming subscriber over the roaming network. An incoming call is routed from the home network to the roaming network that is providing access to the subscriber at the point in time the inbound call is received by the home network. The roaming subscriber is charged a roaming fee for this service and these fees can be in excess of the monthly subscriber's home network fees and many subscribers believe these fees are excessive, but subscribers accept such excessive roaming fees because of the convenience of the service. There is a need therefore for a system and method that eliminates excessive . inbound roaming fees while maintaining the convenience of the mobile device. . Telephone Service providers routinely provide a service called DID trunking. The purpose of the service is to allow PBX and Centrex users inexpensive telephone numbers that can be called directly rather than extensions off a PBX. The PSTN telephone service provider connects a DID trunk to an exchange such as a PBX for Centrex. The Telephone service provider allocates a range of dedicated numbers associated with the PBX or Centrex and associated DID trunk. When any telephone connected to the PSTN dials one of the associated DID range of numbers the telephone service provider recognizes that the DID number belongs to a associated DID trunk and forwards the call from the exchange directly to the PBX or exchange associated telephone and the caller is directly connected to the PBX or exchange telephone extension that rings in directly just like a regular PSTN number. There are long distance service providers who aggregate inexpensive DID telephone numbers from around the world and will sell banks of DID numbers from any country offering

DID and forwarding of these numbers to any destination number over inexpensive wholesale TDM or VoIP networks. We refer to these service providers as Call Forwarding Service Providers CFSP. As is known in the art there are many configurations for deploying such a service, such as a using switches and gateways, and whatever the configuration of technology deployed to provide the service of DID call forwarding receiving DID trunks and numbers from the local

Telco’s and forwarding the calls to the DID numbers or number banks over VolP or TDM facilities to a distant end recipient of the forwarded calls we refer to as the CFSP.

There is a known system and methodology to eliminate inbound roaming fees for mobile phone users comprising the steps of a roaming mobile phone subscriber purchasing a RN and then forwarding their HN to a home location local dedicated DID telephone number provided by a local Call Forwarding Service Provider (CFSP) and having the CFSP subsequently re-forward the DID number over Long Distance Service Provider (LDSP) voice network to the RN.

DID numbers are very inexpensive and home so DID number forwarding is popular and effective but not convenient.

[0006] While methods of redirecting and forwarding telephone calls to DEDICATED DiD number assignments, one for each subscriber RN is known in the art, it would be advantageous to publish a single DID number for each country that subscribers wishing to use to eliminate roaming charges as described above could use. In practice a single DID number called a DID pilot number can be assigned to provide DID call forwarding service for all subscribers in a country or HL. A

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Tr 1

DID Pilot number represents an entire range of DID numbers. Many subscribers can call a DID number at the same time and not incur a busy condition, because the busy condition is limited to the underlying DID trunking as engineered by the

CFSP. When a DID Pilot number called a DID number from the CFSP reserved DID number bank is selected at random provided it is unused at the time of selection, and a unused or free DID trunk is also selected and the connection is made between the PSTN switch providing the DID facilities and the CFSP and the DID number rings into the CFSP switch. When a Calling Party calls the subscribers HN and the HL mobile phone number has been forwarded to an in-country CFSP DID

Pilot number, the pilot number will select a specific and dedicated DID number for that subscriber for that specific phone call. The CTSP could provide a terminating IP address or VoIP gateway to the CFSP so that the HN calls could be forwarded to the CFSP DID Pilot number reserved for the CTSP over an inexpensive VoIP circuit but with existing technology and systems, there is no way for the CTSP to know which incoming call should be forwarded on to which RN number as the DiD numbers are not assigned to specific RN’s but chosen at random after a DID Pilot number is called and the VoIP circuit normally only provides simple calling iD (CID) not called party so there is no way to associate the HN with the incoming call to complete a DID call forwarded to a RN in such a scheme.

There is a need then to invent a system and method to be able to determine which forwarded incoming calls should be routed to which RN's when a pool of shared DID numbers represented by a single shared Pilot number are ringing in to a

CTSP so the CTSP can route an incoming call to the correct RN when there is no apparent and direct relationship between the incoming VolP call and the RN.

In order to route the incoming VolP call to the correct CTSP Subscriber RN number the CTSP must first know the HN 22f not the Calling Party Number (CPN). There is a need to invent a system and method for determining OCN or HN 22f using the CP 8 number for VolP forwarded calls. In accordance with the invention given the differences in the national level for deployment of ISUP messages there is a need to develop an automatic system and method to probe S57 network components of the call setup for OCN from VoIP CID information so that HL Numbers Call Forwarded as VoIP calls to a remote CTSP can be redirected by the terminating CTSP to the correct RN.

Summary of the Invention

It is therefore an object of the invention to provide a system and method for a CTSP which provides RN to subscribers to offer subscribers a shared DID Pilot number per country or per home location that all subscribers from the same country or HL can forward their HN to which re-forwards over inexpensive DID circuits to a CTSP provided RN

The introduction of common control channel signaling CCS has created a standardization of methodology for PSTN call setup. The ITU-T defines a core set of widely used ISDN services in the Q.730 - Q .739 series of specifications using ISUP network signaling. The actual specifications of these services at the national level can vary. In addition networks often offer services outside of those that are specified by the ITU-T. ISUP provides the flexibility to accommodate these differences using a rich message set in a large set of optional parameters.

It is an object of the invention to use CCS messaging to query the origins of a CCS Network originated call but non CCS terminated call to determine the CCS Network stored information from the original SSP and use this information to overcome the limitations of lack of called number information from DID forwarded VoIP calls.

Itis a further object of the invention to create a method for the CTSP to determine the HN called for each forwarded incoming VoIP call from the CFSP so that the HN can be matched to the RN and the HN call forwarded to the RN to complete the incoming VolP call.

The invention will be CHARACTERIZED BY;

A system and method of using the incoming VoIP CID information to determine the called HN by way of utilizing S57 or

C7 CCCS messages to probe the originating SSP or SCP or originating MSC for the called HN. The invention will describe the system and method of determining the called HN associated with the incoming VolP call by way of using CCS

Network.

Further the invention will provide a method for the CTSP to match the Called HN to the associated RN so that the CTSP will be able to automatically re-forward the incoming VolP call from the terminating IP address to the RN and complete the incoming call.

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The invention enables a practical way for mobile phone service providers to deploy a convenient worldwide DID call forwarding service designed to eliminate inbound roaming charges for subscribers outside their HLN.

BRIEF DESCRIPTION OF THE DRAWINGS

[0007] Further features and advantages of the present invention will become apparent from the following detailed description, taken in combination with the appended drawings, in which:

[0008] FIG. 1 schematically illustrates principal elements of one embodiment of the invention for eliminating inbound roaming charges for mobile devices.

[0009] FIG. 2 is a call flow diagram illustrating principal steps involved in providing an incoming VolP call termination service, in accordance with the invention where the incoming VoIP call is routed to the CTSP supplied RN.

[0011] FIG. 3 is a call flow diagram illustrating a connection established in accordance with the invention where an

ISUP message is passed from POP to POP and the Call forward CLI is altered by each POP, converted to simple CID and the rich ISUP IAM message data is lost.

[0012] FIG. 4 is a call flow diagram illustrating the principal steps required to implement the call forwarding environment in accordance with the invention.

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Page 8 of 13

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

[0013] The invention provides a system and method for controlling remote call termination by a telecommunications service provider in order to eliminate incoming roaming charges to mobile subscribers outside their home locations but inside a remote home location of a (CTSP) Call Termination Service Provider deploying the invention. A CTSP is capable of providing subscribers local SIM cards and a related call termination service capable of facilitating the call forwarding of a subscriber’s HN to a CFSP provided HL DID number which then automatically connects to the CTSP provided RN 35f number over a VolP DID/ LDSP service when a CP 8 calls the subscribers HN 20f.

In the example of the preferred embodiment, ISUP Supplementary Services calling line identification (CLI) and call forwarding unconditional (CFU) information or simply the CP original called number (OCN) which is also the subscribers

HN 20f can be retrieved from the CCS Network 24 and associated switches and SSP’s 31 even when a call was only partially completed over such a network and the information can be used to automate the forwarding of the HN 20f to the RN 35f worldwide in spite of the fact that many versions of ITU-T are deployed worldwide.

[0014] FIG. 1 schematically illustrates principal signaling components of a system 8 in which the invention may be deployed. The system 8 involves a plurality of mobile telephone communications devices, and a broader group of wireless and wireline telephone terminals

The mobile telephone communications devices include CDMA or GSM WD 4, and portable communications devices that feature telephony capabilities. As is well known in the art, such mobile telephone communications devices are in wireless communication with mobile switching centers (MSC) 32, 35 through respective transceivers 20e, 35e. The MSCs 32, 35 access home location registers 20d,35c (HLRs) and visiting location registers 21d, 35d (VLRs) to provide control and hand-off of calls in progress, etc.

[0015] Today's public switched telephone network (PSTN) 22 is an aggregation of bearer networks that, in some cases, also provide control signaling as well. Overlaying much of the PSTN 22 is a common channel signaling (CCS) network 24, which, in North America, is almost uniformly a signaling system number 7 (S57) network and in the rest of the world C7.

Herein when we refer to S57 we mean SS7 or C7 messaging. MSCs 32, and 35 which are part of the PSTN 22 are usually connected to the CCS network 24 as is the PSTN for call control signaling purposes, and to the PSTN 22 for trunking purposes. As is well known in the art, call control signaling is messaging used to establish, maintain and tear down trunk connections between switches in the PSTN 22; whereas the trunking serves to support transport of voice and data between end points of established telephone calls.

[0016] The worldwide PSTN is made up of landline components and wireless components that share a common public numbering plan, and calls between mobile devices and landlines are set up in any combination using S57 and C7 messaging to instruct PSTN and private switches interconnecting the calls exactly how and when to make connections.

These SS7 and C7 messages referred to as common control channel signals CCCS can request detailed information on the status of any call in determining called numbers, call forwarded conditions for called numbers, the originating called numbers (OCN) and the terminating number (TN) for example by examining different portions of this call process as is well known in the art of common control channel signaling.

Included in the PSTN are switching end points that are often referred to as SSP or SSP System. SSP 31 is a SSP system as

SSP 31s intended to include a Signal Transfer Point or STP involved in routing messages between the SSP and the CCS over and SS7 Access Link or A-Link 11 and a Service Control Point (SCP). The SSP 31 creates SS7 messages that are sent to a SCP to query databases for subscriber service and routing information. SSP 31 is an end office and switching system of the PSTN and includes analog telephone interfaces enabling interconnection of wireline 32 and ISDN telephones and

PBX. The SSP extracts and processes signaling information between these devices and the SS7 network that interconnects the entire PSTN including MSC 32 and MSC 35. The SSP performs call processing on calls that originate from the devices connected to the SSP 31 and calls that terminate on SSP 31 both features which are important for the

CTSP to query the SPC or SCP for Calling Number Called Number information that will be used by the CTSP to match incoming VoIP calls to the RN. SSP 31 may generate or receive SS7 Messages to transfer call related information or may send queries to SCP’s to discover information related to call processing specifically the OCN related to the incoming VoIP call at the CTSP SSP or POP. An SSP SYSTEM 31 is a system that includes, the SSP, SCP and STP functions as well as complete voice switching capabilities. For the purposes of simplicity we do not include all of the components of SSP 31

Page 9 of 13 in FIG 1. rather describe SSP 31 as a fully provisioned SSP SYSTEMS. For further simplicity and clarity CFSP 33 and CTSP 34 have been described based on their simplest configurations but may also be SSP SYSTEMS.

[0017] Of particular importance to the invention is a Call Termination Service Provider (CTSP) SSP 35 which is a switch in the PSTN 22 connected to an MSC 35 directly through ISDN 19 or indirectly through other POP’s inside a Telco

Network that will be connected to the CCS network 24 either directly or through an MSC or SSP SYSTEM connected to the CCS network 24 and the SSP System may not necessarily serve subscribers directly but support an MSC that does by providing final leg terminating number (TN) information in this case the RN 35f to the MSC by bridging direct circuit connectivity such as ISDN PRI (Primary Rate interface) or by way of Common Control Channel Signaling.

[0018] The CTSP 34 can be supported by call PC Servers 27 that run database applications to provide information to the CTSP 34 so that the CTSP 34 is able to route the incoming forwarded VoIP call from subscriber HN 20a to the same subscriber RN.

CTSP 34 could be a switch without subscribers performing the CTSP34 functions of call routing for MSC 35 for calls forwarded over the CFSP 33 VoIP 16 calls to the appropriate subscriber RN . The CTSP functions may be as follows; providing an IP address or IP trunking 16 for temporarily terminating forwarded CFSP 33 calls. Such calls would be inspected for Calling ID on incoming ringing or by extracting from Session Initiation Protocol (SIP) packets. Calls would then be held and the CTSP 34 would request from the CTSP SS7 CCS Network Message Format database 27b an appropriate query method based on the location of the incoming call determined by the CID. The CTSP S57 database 27b may simply instruct the CTSP 34 to setup a call to the number CP number indicated by the CID as a method to receive SSP 31 ISUP related Messages using SS7 ISUP signaling and CTSP34 will receive a host of call setup messages in response from SSP 31 indicating the ISUP message routing label for the CP 8 SSP 31 now providing the CTSP 34 enough information about the held call to probe the SSP 31 further for the called number related to the CP number 5. Once the CP8 associated Called Number which we refer to as the HN 20f and in ISUP CLI terminology is referred to as the OCN, the

CTSP 34 may then send the HN 20f or OCN to the CTSP 34 profile database and match the HN 20f with the RN 35f, return the RN 35f to the CTSP 34 and then call the RN 35f and bridge the call to the held associated VoIP call.

In accordance with the invention, a profile database 27c¢ is further adapted to provide storage of a terminating number

RN 35f associated with a DID (pilot) number 9 and HN 20f, and each subscriber to the CTSP 34 services is identified by a purchased local SIM card, and calls to the associated (DID) number of a subscriber are directed to a CTSP 34 current termination number which in the case of an IP call is an IP address or VolP Gateway. In accordance with the illustrated embodiment, the relationship between the termination number RN 35f and OCN or HN 20f is held in a table called the

RN/HN table 27d.

[0019] The CTSP System 27 naturally comprises a (request) processor for receiving a queries from the CTSP 34 switch and, and returning a termination number associated with the OCN included in the query. The CTSP System 28 also includes an OCN probe processor that determines the change of termination number by probing the ISUP Call

Forwarding Messages associated with respective forwarded HN to DID call forwarded numbers to determine the match between circuit and RN. Probe processor returns and parses the $57 and C7 messages and sends the RN CPN associated with the DID extension to the CTSP 34 Call Hold Queue and once a valid entry is returned the DB runs a stored procedure instructing the CTSP 34 switch to call the RN and bridge the call or un-hold the call and call forward the call to the RN.

The probe processor preferably also authenticates and validates a format of the change of termination number messages.

In accordance with the present invention the identification of calls requiring further processing is dependent on the terminating nurnber or IP address the forwarded call arrives on at the CTSP POP 35.

Once the called number (OCN) HN is returned, the CTSP then queries a translation database to determine which final

TN or RN in this case the call is to be connected to by mapping the TN or RN number associated with the HN in the CTSP translation database and initiates a new call request to complete the call from the CTSP 34 to the MSC 34 RN.

Otherwise in step 241 an error message is played. The error message may indicate that the number dialed is not in service or that the subscriber is not currently receiving calls our out of range of service or his device is turned off.

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In order to facilitate a system whereby a CTSP 34 could offer subscribers a call forwarding number that a CTSP 34 subscribers could forward their HN 20f to enable their HN 20f to ring to a CTSP 34 provided RN 20f the CTSP 34 would have to maintain a database of DID Pilot numbers for each country in the world or HN 20f that the CTSP 34 wanted to serve. The principal steps of setting up such a database of world DID pilot numbers is shown in FIG. 4. In Step 100 a CTSP 34 applies to a CFSP 33 that maintains a worldwide inventory of DID numbers. In step 101 the CTSP 34 would also request from the CFSP 33 a pilot number which is a single number well known in the art of delivering DID numbers which when called by a CP 5 then selects a free trunk and free DID number that is used in the process of call setup.

In Step 102 the CTSP 34 provides a terminating IP address and configuration and VolP gateway information as is well known in the art form of VoIP voice connectivity so that the CFSP 33 can unconditionally call forward all calls directed to any DID pilot number to the CTSP 34 VOIP destination address and gateway where all CFSP 33 worldwide DID forwarded calls will be terminated. in Step 103 a person traveling to the CTSP 34 location may purchase a SIM card and associated mobile phone number called RN 35f number so that when they make outgoing calls they will not be charged for outgoing roaming fees. As a method to attract more travelers to purchase the CTSP 34 SIM cards and associated RN 35f numbers the CTSP 34 may offer the CTSP 34 service where the CTSP 34 service can eliminate inbound roaming charges to the CTSP 34 subscribers

HN 20f by providing the subscriber with a HN DID PILOT number in the subscriber HNL 20 and then asking the subscriber or assisting the subscriber in call forwarding the subscribers HN 20f to the CTSP 34 HLN DID Pilot number.

In Step 104 to ensure that the HN 20f forwarded to the HN DID PILOT number rings the CTSP 34 provided RN 35f so that calls from the HN 20f can be received on the RN 35f the CTSP 34 will create a subscriber profile in the CTSP DB 27 and populate the specific CTSP subscriber profile DB 27b with the most important information being the subscribers HN associated with the newly purchased CTSP 34 provided RN 35f in Step 104

In Step 105 the CTSP 34 provides the subscriber with the subscriber HNL DID Pilot number which will be shared with anyone from the same HLN 20 or perhaps nationality.

In Step 106 the subscriber forwards their HN 20f to the HNL 20 CTSP 34 provided DID Pilot number and all calls to the HN 20f will now ring through to the CTSP system 27 whereby a series or process and stored procedures will ascertain which incoming call is destined for which RN 35f.

FIG. 2 illustrates just one embodiment of the part of the invention which automatically determines the HN from the VolP

CID and then automatically connects the HN 20f to the RN 35f to complete the conversation while avoiding inbound roaming fees.

FIG. 2 is a call flow illustrating the principal steps in establishing a forward call connection completed in accordance with the invention. In the example in step 200 wireline device 2 goes off hook, it is irrelevant if the initiating device we refer to as the called party is a wireline device or a mobile device as long as the device is capable of calling the (OCN ) Original

Called Number we refer to as the HN 20f interchangeably.

In step 205 SSP A 31 receives the off hook signal from wireline device 2 and plays dial tone to wireline device 2. In step 210 wireline device 2 dials the HN 20f which is resident in a HLR 20d. In step 215 SSP A 31 sends an (IAM) Initial Advisory

Message to MSC B 32. In step 220 when MSC B 32 attempts to terminate the call and encounters the Call Forward

Service, where the HN has been forwarded to a local DID number hosted by SSP C 33 in step 225 a new IAM is sent to SSP

C 33. The additional parameters in the {AM include the Redirection Information (RI), Redirecting Number (ReN) and

Original Called Number (OCN). As is well known in the art there are many conditions for call forwarding such as call forward busy, call forward no answer, call forward unconditional etc.

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All conditions of call forwarding are acceptable for the purpose of this invention and we will employ the case of cali forwarding unconditional for the purpose of simplicity and clarity (CFU). The ReN is usually the same as the OCN and is so in this case as this is the first Call Forwarding Hop. In subsequent Hops the IAM changes reflecting a new ReN and Called

Party Number (CPN) but the OCN stays the same. On multiple forwarding’s as we have in the example the ReN is the number of the last station that forwarded the call. The CPN will be set to the “forward to number” as indicated by the

ReN.

In step 230 the OCN or HN at has been directed to the pilot number of a bank of DID numbers resident on the CFSP 33 switch and the pilot number selects the first free DID number. In this case CPN is not the CPN specified in the IAM message step 225. In our invention any called number in the DID number bank is forwarded to a single pilot number or IP address or IP trunk group at the remote CTSP. In step 230 to step 235 the SSP C 33 on encountering the CFU condition forwards the TDM call to a VoIP gateway or softswitch and directed the VoIP call to CTSP 34 without using CCSN 24.

FIG. 3. 10 the CLI IAM shown, the OCN or HN is 1 212 888 3333, and the ReN is 1 212 888 3333 and the CPN is 1 212 777 3000. Call connection is attempted to the CPN which is actually a DID Pilot number and as weil known in the art of DID provisioning, the DID provisioning PSTN switch (which has not been shown for reasons of simplicity and clarity) selects a free DID trunk and assigns a free DID number and connects to the CFSP switch 33. At CFSP 33 all of the number bank has been forwarded CFU (although any call forward condition is acceptable) to the CTSP SSP 34 remote pilot number or in this case IP address or IP trunking group and only the OCN or HN 20f information will be forwarded with the call in our example FIG. 3 1212 888 3333. When the CTSP 34 receives the incoming call and inspects the call the CID is read, the call put on hold and the CID sent to the CTSP HN/RN table 27c in step 251 and if an HN 20f match is found the RN 35f is returned and the process moves to step 280 and step 285 and the call completed and processed ends.

If the CID in step 251 does not match then the CID is not the HN 20f but possibly the CP 8 number and the HN 20f must be ascertained by one of the process of the invention as follows:

In FIG 3 step 240 the CLI message fails to return the HN 20f which is often the case if the CP 8 is a Wireless device 4. A key element of the invention lies in the system and method of using the CCS Network 22 to obtain in an automated manner the HN 20f from the CPN 5, and automatically re mapping and re routing the incoming call to the appropriate RN 35f.

As is well known in the art there are many methods of using CCCS messages to retrieve CLI calling information. Using message routing labels and CIC information the CTSP 34 can request from the CTSP DB 27b the best message format given the information supplied by the final CID namely the national origination of the call.

In FIG 2 step 251 the VoIP returns the CPN not the required HN. As is known in the art of VoIP call setup connectivity and use of the CCS Network 24 is possible and sometimes deployed by VoIP LDSP but often not and this embodiment deals with the situation where the VoIP LDSP does not interface or use the CCS Network 24 for call setup and as a result there is very limited calling information to extract from the VolP call to ascertain the original HN 20f so that the CTSP 34 can not directly match the incoming VolP call information to ascertain the HN 20f to match then to the RN 35f and complete the calling process. In step 245 the CTSP 34 must then indirectly ascertain the HN 20f from the CID call answered, and held in queue by probing the PSTN CCS Network 22 interfaced switches. In order to retrieve additional calling information the CTSP 34 must query CCS Network 22 supported switches SSP 31 and or MCS 32 and their supporting databases often referred to as SCP and retrieve the HN 20f calling information associated with the VoIP call 11 coming in on IP trunk 16.

There are many methods to accomplish the task of probing the PSTN network to retrieve the CID associated HN number using S57 signaling messages and in Step 252 just one of the methods is described, but this invention and embodiment is not limited to this particular method and these steps but limited to the method of using ISUP, TCAP or MAP CCS Network

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Messages to probe the SSP 31 and SSP 32 to ascertain the HN 20f that is known and stored in the data bases of SSP 31 and SSP 32 for the purposes of call setup and billing and circuit assignment.

In Step 285 CTSP sets up call to the CID number resident on SSP 31 using SS7 network messaging which creates a host of

ISUP messages between the end points SSP 31 and end point CTSP 34. As the call progresses a host of ISUP messages ensues providing routing information and called number status by way of the call setup ISUP messages flowing between the two SSP end Points SSP 31 and CTSP 34. By utilizing this information and CTSP 34 providing this information to CTSP

DB 27 and specifically CTSP DB 27b, CTSP 27b database will decide if further probing of the CCS network is required to return the HN 20f and the ensuing probing is not limited to ISUP message but any appropriate CCS Network 24 message format such as transactional capabilities application part (TCAP} or mobile application part (MAP) as well as ISUP or any other known message format capable of retrieving the HN information from SSP 31 or MSC 32.

In step and 254 the initial advisory message (IAM) is received by the CTSP 35 and the IAM is used to directly or indirectly obtain the calling line identification (CLI) information retrieving the OCN and sending the OCN to the CTSP DB where the

CTSP DB understanding that the OCN is the same as the HN query the CTSP Profile DB 27c in step 272 and maps the HN 20f to the RN 35f in step 275. In step 256 the CTSP issues a RLS command to tear down the requested call between SSP 31 and CTSP 35 and a cascading string of ISUP signals ensues to facilitate the process of call tear down and circuit release and all of the ISDN information can be further used to verify the HN 20f number.

In Step 280 the CTSP Profile DB 27c returns the RN 35f to the Call Hold/Queue DB 27a and in Step 281 to 285 the RN and the Call Queue DB 27a returns to the CTSP 34 the appropriate call connection instructions to the CTSP 34 which is not limited to or confined by order the Steps 285 to Steps 285, seize an outgoing PSTN trunk Step 282, dial the RN 35f digits in Step 283 to effect the call in progress to the RN 35f in Step 285 by un-holding the call held in Step 250 and bridging the call held in Step 250 to the RN call in progress to the appropriate held call in Step 250 and the conversation in Step 325 ensues.

The invention therefore provides a plurality of methods of using CCS Messaging to determine the OCN or HN from a non

CCS Network completed call. The network configurations and methods for obtaining the OCN or HN 20f are not exhaustive and the methods for mapping the HN 20f to the RN 35f are not exhaustive.

The embodiments of the invention described above are exemplary only. The scope of the invention is therefore intended to be only limited by the scope of the claims.

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Claims (11)

1. NAAR § oo *164164* i The method and system in accordance with the invention therefore provide a powerful and convenient tool to permit travelers to avoid incoming roaming charges while traveling abroad by forwarding their mobile phone number to a single DID number pilot number shared by all travelers which is re-forwarded to a SIM card that the traveler purchases in the distant country so that a local call is forwarded over a VoIP circuit to a local SIM card purchased by the traveller avoiding all roaming charges with the convenience of all travelers sharing the forwarding number to serve all of their forwarded calls. The system and method providing a single number for all to share for forwarding calls will be understood by those skilled in the art, the above examples show one potential implementation of the system in accordance with the invention. Many variations on the implementation of the system are feasible. The embodiments of the invention described above are therefore intended to be exemplary only. The scope of the invention is therefore intended to be limited solely by the scope of the appended claims. We claim:

   1. A method of eliminating incoming roaming charges comprising the steps of: a) a mobile phone subscriber forwarding their mobile phone number (HN) to a DID pilot number and the DID pilot number having a range of associated DID numbers in a hunt group and the hunt group is associated with DID trunk that terminates at a call forwarding service provider (CFSP) such that when a calling party calls the mobile phone number which has been forwarded to the DID pilot number the DID pilot number assigns a free DID number and selects the associated DID trunk that rings in on call forwarding service provider switch or server (CFSP) b) where the CFSP server gathers the incoming call data including but not limited to the forwarded subscriber mobile phone number, the assigned DID number and trunk identification number and stores this information in a CFSP call log in the CFSP database ¢) where the CFSP server or switch then re-forwards the incoming call to a distant end call terminating service provider (CTSP) over a VoIP circuit where the CTSP identifies the : incoming call as a CFSP forwarded call d) where the CFSP sends the forwarded mobile subscriber phone number to the CTSP : e) where the mobile phone subscriber when in the distant country has purchased a local SIM card from a CTSP provider and the CTSP provider updates a CTSP translation table database associating the purchased SIM card number with the mobile phone subscriber number (HN) f) then the CTSP on receiving the forwarded incoming call from the CFSP and subscriber mobile phone number (HN) maps the subscriber mobile phone number (HN) to the local CTSP provided phone SIM card associated with the subscriber mobile phone number and then re-forwards the call to the local CTSP SIM card completing the call.
2. 2. A method as claimed in claim 1 where the step of call forwarding the mobile phone subscriber phone number (HN) to the CFSP DID number can be completed from in-country or when at the distant location
3. 3. A method as claimed in claim 1 where the CFSP database is maintained but not limited to, in the cloud, at the CTSP remote location or at the location of the CFSP location or part of the CFSP or CTSP Mobile Switching Center (MSC) database including MAP database, HLR or VLR or a specialized database for the purpose of mapping the HN to the RN.

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4. 4. A method as claimed in claim 1 where the CFSP server or switch then re-forwards the call to the CTSP server or switch and the switches and the servers couid be VoIP servers or TDM or SIP servers or switches or any combination of VoIP and TDM switches or SIP switches.
5. 5. A method as claimed in claim 1 where the CFSP server or switch then re-forwards the call to the CTSP server or switch and the CTSP recognizes the incoming call as a CFSP forwarded call by but not limited to the incoming trunk number or assignment, IP address range, TDM terminating Trunk Group, IP address, TDM or VolP server or switch or a special incoming call identification, indicating to the CTSP that the call has originated from the CFSP switch.
6. 6. A method as claimed in claim 1 where the CFSP does not send the forwarded mobile subscriber phone number to the CTSP, but the CTSP must probe the CFSP or Telecom Service provider database by receiving the call forwarded DID number from the CFSP then accessing the CFSP call log in the CFSP database and matching the forwarded call DID number to the mobile phone subscriber number which is then used by the CTSP to map the mobile subscriber phone number (HN) to the purchased local SIM card from a CTSP provider associated with the subscribe mobile phone number.
7. 7. A method as claimed in 6 further comprising the steps of: a) Where the CTSP uses a MAP message to query the HLR Telecom Service provider call record database for the forwarded call associated subscriber mobile phone number. b) Where the CTSP uses a MAP message to query the DID Telecom Service provider call record database which may or may not be a HLR database for the forwarded call associated subscriber mobile phone number. c) Where the CTSP uses a TCAP message to query the Telecom Service provider call record database for the forwarded call associated subscriber mobile phone number. d) Where the CTSP uses a TCAP message to query the DID Telecom Service provider call record database which may or may not be a HLR database for the forwarded call associated subscriber mobile phone number. e) Where the CTSP uses an ISUP message to query the Telecom Service provider call record database for the forwarded call associated subscriber mobile phone number.
8. 8. A method as claimed in 1 where the CFSP server gathers the incoming call data and stores the data in a CFSP cal! log and where the mobile phone subscriber when in the distant country has purchased a local SIM card from a CTSP provider and the CTSP provider updates a CTSP translation table database associating the purchased SIM card number with the mobile phone subscriber number (HN) and both the CFSP database and the CTSP databases are the same database accessible by both the CFSP and the CTSP.
9. 9. A method as in claim 1 where the CFSP and the CFSP could be one and the same entity with cloud based servers
10. 10. A method as in claim 1 claimed in 1 where the CFSP could be the Telecom Service provider.

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11. 11. A method as in claim 1 where the mobile phone subscriber when in the distant country has : purchased a local SIM card from a CTSP provider and the CTSP provider updates the : CFSP translation call log table database associating the CTSP provided purchased SIM : card number with the mobile phone subscriber number and the CFSP then re-forwards the received forwarded incoming call from the forwarded mobile subscriber phone number to the CTSP distant end purchased SIM card eliminating the need for translation table matching or i database queries. { !