WO2000056109A1

WO2000056109A1 - Dynamic call transferring

Info

Publication number: WO2000056109A1
Application number: PCT/SE2000/000221
Authority: WO
Inventors: Stephane Morin
Original assignee: Telefonaktiebolaget Lm Ericsson (Publ)
Priority date: 1999-03-18
Filing date: 2000-02-04
Publication date: 2000-09-21
Also published as: AU2839800A

Abstract

A system, method, and apparatus for dynamically transferring a call from a mobile station (135) to a third party terminal (305) are presented. By selecting a dynamic call transferring feature from the mobile station, a subscriber can dynamically designate (457, 574, 674) a third party terminal number (a C-number) to transfer an incoming or pending call from a mobile station, while the mobile station is in a paging, alert, or voice mode. Responsive to selection of the dynamic call transferring feature and designation of the C-number while the mobile station is in the paging, alert, or voice mode, the mobile station transmits a call transferring signal (457, 574, 674) and the C-number to the telecommunications network. Upon receiving the call transferring signal and the C-number, the telecommunications network transfers the incoming or pending call to a third party terminal associated with the C-number.

Description

DYNAMIC CALL TRANSFERRING

BACKGROUND OF THE INVENTION Technical Field of the Invention The present invention relates to a telecommunications network and, in particular, to dynamically designating from a mobile station a third party terminal to which an incoming or pending call should be transferred. Description of Related Art

With the advent and development of mobile telecommunications systems, telecommunications users are no longer physically bound to wireline terminals or fixed locations for telecommunications network communications. Using the added capabilities of roaming and interoffice handoffs, mobile subscribers may travel between multiple Public Land Mobile Networks (PLMNs) utilizing the same telephone number and the same mobile station to originate outgoing calls and to receive incoming calls. Thus, a mobile subscriber may access a telecommunications service from multiple locations utilizing multiple service providers with any incurred fees being charged to a single subscription.

Additionally, parties originating a call do not necessarily have to know where the desired mobile subscriber is physically located in order to properly route and to establish a call connection. Data signals between visitor location registers (VLRs) and a home location register (HLR) automatically update and store subscriber information enabling the network to reroute incoming calls to the appropriate mobile switching center (MSC) serving the roaming mobile subscriber.

In general, wireline telephones are less expensive than wireless mobile stations but without the aforementioned mobility-related advantages. Therefore, a calling party may call a subscriber using a number associated with the subscriber's mobile station to increase the probability that the subscriber will be available to answer the call. Where the subscriber is away from their home or office, the mobile station may well be the only means to connect a call to the subscriber. However, when the subscriber has access to a wireline telephone, it is unnecessary and unduly expensive to contact the subscriber on the mobile station.

Calling the subscriber using the available wireline terminal requires that the calling party know the phone number of the available wireline terminal. Where the calling party is not aware of the phone number of the available wireline terminal, the subscriber can take the incoming call on the mobile station and briefly make arrangements to continue the conversation on an available wireline terminal. Taking the incoming call on the mobile station incurs charges for even the brief time needed to make alternative arrangements on an available wireline terminal. Another possible solution, where the mobile station has calling party identification, is to observe the calling party's number, wait for the calling party to abandon the incoming call, and return the call to the observed calling party number from the wireline terminal. The foregoing requires calling party identification and that the calling party terminal be capable of receiving incoming calls. However, not all terminals are capable of receiving incoming calls. For example, many pay phones are not capable of receiving incoming calls.

Another possible solution would be to use call forwarding to transfer incoming calls for the mobile station to the wireline terminal number. Using conventional call forwarding does not require the calling party to know the number of the wireline terminal and does not require the subscriber to answer the call at the mobile station.

Initiating call forwarding involves a static set up procedure which must occur prior to the incoming call, wherein the user pre-stores in the network HLR the phone number (C-number) of the terminal to which calls are to be transferred. Therefore, the subscriber must designate the C-number without knowing the identity of the calling party. However, where a subscriber chooses to transfer a call may depend on information known only at the arrival of the call. For example, where a subscriber visits numerous places in a day, the C-number may change, depending on the time the incoming call arrives. In another example, a subscriber with calling party identification may observe the calling party identity, and based on that identity, determine the C-number, or even decide to use the mobile station. Therefore, it would be beneficial if a means for allowing a mobile subscriber to dynamically transfer an incoming phone call or pending call to a subscriber specified C-number during the alert mode or voice mode were provided.

SUMMARY OF THE INVENTION The present invention is directed to a system, method, and apparatus wherein a subscriber can dynamically designate a third party terminal number (a C-number) to transfer an incoming or pending call from a mobile station, while the mobile station is in a paging, alert, or voice mode. When in either the paging, alert, or voice mode, the subscriber can specify a C-number to which the incoming or pending call should be transferred by providing certain inputs to the mobile station. Upon receiving the inputs, the mobile station transmits signals and the C-number for that call as specified by the user to the telecommunications network. Upon receiving the signals, the telecommunications network transfers the call to the C-number that was provided for that call.

BRIEF DESCRIPTION OF THE DRAWINGS

The disclosed invention will be described with reference to the accompanying drawings, which show important sample embodiments of the invention and which are incorporated in the specification hereof by reference, wherein:

FIGURE 1 is an exemplary wireless network wherein the present invention can be practiced;

FIGURE 2 is a block diagram of a mobile station configured in accordance with the present invention;

FIGURE 3 is a signal flow diagram illustrating the operation of a telecommunications network in accordance with the present invention; and FIGURES 4 A, 4B, and 4C are signal flow diagrams illustrating the operation of a telecommunications network in accordance with the present invention.

DETAILED DESCRIPTION OF THE DRAWINGS

Reference is now made to FIGURE 1 wherein there is shown an exemplary wireless network 105, such as a Public Land Mobile Network (PLMN). The PLMN 105 may comprise, for example, an Advanced Mobile Phone Service (AMPS) network, a Digital Advanced Mobile Phone Service (D-AMPS) network, or a Global System for Mobile Communication (GSM). The PLMN 105 is composed of a plurality of Mobile Switching Center/Visitor Location Register (MSC/VLR) areas 115, each with a Mobile Switching Center (MSC) 120 and a Visitor Location Register

(VLR) 125. Each MSC 120 is connected to a Gateway MSC 127 which connects the PLMN 105 to a public switched telephone network (PSTN) 128 serving a plurality of wireline terminals 129.

The MSC/VLR area 115 is the area in which a mobile station (MS) (terminal) 135 may move freely without having to send update location information to the

MSC/VLR area 115 that controls it. Mobile Station (MS) 135 is the physical equipment, for example a car phone or other portable phone, used by mobile subscribers to communicate with the cellular network 105, each other, and users outside the subscribed network, both wireline and wireless. Each MSC/VLR area 115 is divided into a number of cells 140. The MSC 120 is in communication with at least one Base Station 150. The base station 150 is the physical equipment, illustrated for simplicity as a radio tower, that provides radio coverage to the geographical part of the cell 140 for which it is responsible.

With further reference to FIGURE 1, the PLMN 105 includes a Home Location Register (HLR) 126, which is a database maintaining and storing subscriber information such as subscriber profiles, current location information, International Mobile Subscriber Identity (IMSI) numbers, and other administrative information. The subscriber services associated with the mobile station 135 are defined in a subscriber profile that is stored in the HLR 126. The HLR 126 may be co-located with a given MSC 120, integrated with the MSC 120, or alternatively can service multiple

MSCs 120, the latter of which is illustrated in FIGURE 1.

The VLR 125 is a database containing information about all of the Mobile Stations 135 currently located within the MSC/VLR area 115. If a MS 135 moves from MSC/VLR area 115a to a new MSC/VLR area 115b, the VLR 125b connected to the MSC 120b in the new MSCNLR area will request data about that MS 135 from the HLR database 126 (simultaneously informing the HLR 126 about the current location of the MS 135). Accordingly, if the user of the MS 135 then wants to make a call, the VLR 125b in the new MSC/NLR area 115 has access to the requisite service profile information without having to reinterrogate the HLR 126. In the previously described manner, the VLR and HLR databases 125 and 126, respectively, contain various subscriber information associated with a given MS 135.

Among the available subscriber features stored in the HLR 126 is call forwarding no answer. Call forwarding no answer is a subscriber feature which allows a subscriber to direct incoming calls dialed to MS 135 to a different MS 135 or wireline terminal 129 associated with a user selected directory phone number. Call forwarding no answer is set up by pressing a special code, e_g_, "*72", from the MS

135, followed by a directory phone number known as the C-number. After call forwarding no answer is set up, the entered C-number is stored in the HLR 126. When an incoming call to the MS 135 is subsequently placed, the call is routed to the Gateway MSC 127. When the incoming call is routed to the Gateway MSC 127, the Gateway MSC 127 responds by querying the HLR 126 for the subscriber location by sending a location request. The HLR 126 responds by requesting a routing number (such as a temporary location directory number (TLDΝ) or a roaming number) from the serving MSC 120. The serving MSC 120 responds by paging the MS 135 and upon receiving a response to the page, the serving MSC 120 assigns a routing number to the MS 135 and sends the routing number to the Gateway MSC 127 via the HLR

126. The Gateway MSC 127 then through connects the call through the serving MSC 120 which alerts the MS 135. After alerting the MS 135 for a predetermined period of time, and receiving no answer from the subscriber, the serving MSC 120 sends a redirection request to the Gateway MSC 127. The Gateway MSC 127 responds by querying the HLR 126 for a C-number to forward the incoming call to . The HLR 126 responds by retrieving the C-number from the subscriber profile and transmitting the C-number back to the Gateway MSC 127. The Gateway MSC 127 then routes the call to the C-number.

It is noted, however, that call forwarding no answer must be set up, and the C- number must be determined prior to the arrival of the incoming call. In certain circumstances, it may be preferable for the subscriber to determine whether to forward the call, as well as where to forward the call, at the time the incoming call is either being set up, arrives, or perhaps even during the established call. For example, a subscriber receiving an incoming call at the MS 135 may choose to forward the call to a nearby wireline terminal 129 to reduce the cost of the call. Alternatively, with calling party identification a subscriber may observe the calling party identity, and based on that identity, determine where to transfer the incoming call. In another example, the subscriber may take the incoming call and during the course of the conversation, forward the call to another party.

To permit a subscriber at a MS 135 to request forwarding an incoming call at call set up or after the call arrives, the present invention proposes an additional dynamic call transferring feature to be included with the MS 135. When a called party at MS 135 selects the dynamic call transferring feature, the MS 135 responds to a page, or a ring alert, or alternatively specifies during call mode, by transmitting a signal and a C-number which is associated with another MS 135 or a wireline terminal 129. In response to this signal and C-number, the serving PLMN 105 transfers the incoming or pending call to the MS 135 or wireline terminal 129 associated with that specified C-number.

Referring now to FIGURE 2, there is illustrated a block diagram of a MS 135 embodying the present invention. The MS 135 comprises a radio transceiver 205, a speech circuit 210, a speaker 215, a microphone 220, and a keypad 225. A controller

230 causes the radio transceiver 205 to receive signals from a base station 150. The controller 230 is also associated with a phone number memory 235 which is partitioned into user-definable storage locations 240 to store phone numbers. The phone number memory 235 can store any number of phone numbers, each associated with a particular wireline terminal 129 or another MS 135. The user can enter information via the keypad 225 to the controller 230 to be stored in the phone number memory 235 in a manner well known in the art. A display unit 270 can also be used to assist and prompt the user while entering the information in a manner also well known in the art. The controller 230 also executes instructions implementing specialized features and functions of the MS 135. The user selects a feature or function by providing certain inputs to the controller 230. The user can provide inputs to the controller 230 by, for example, inputting a code associated with a particular function via the keypad 225. Alternatively, the keypad can include various function keys, wherein each function key, when pressed, provides inputs to the controller 230, causing the controller to perform a function associated with the particular function key. Upon receiving the input code, the controller 230 executes the instructions implementing the particular feature selected by the user.

Among the features supported by the controller 230 include dynamic call transferring. By selecting dynamic call transferring and designating a C-number during an incoming call setup or during an ongoing call, the controller 230 causes the radio transceiver 205 to transmit a signal and a C-number to the serving PLMN 105. When the PLMN 105 receives the signal and the C-number, the PLMN transfers the incoming or pending call at the MS 135 to a wireline terminal 129 or MS 135 associated with the C-number. The C-number can be designated in a number of different ways. For example, the subscriber can directly enter the C-number from the keypad 225 prior to selecting the dynamic call transferring feature. Alternatively, the subscriber can enter a code associated with a particular location 240 of the phone number memory 235, causing the phone number stored therein to be designated as the C-number and included in the signal, in a manner analogous to speed-dialing. Referring now to FIGURE 3, there is illustrated a signal flow diagram describing the operation of the telecommunications network. A call (signal 350) is placed from a calling party terminal 305 a directed to a mobile station 135b. The calling party terminal 305 a can comprise either a wireline terminal 129a or another MS 135a. The call from the calling party terminal 305a is routed (signal 353) to the Gateway MSC 127 of the PLMN 105 serving the MS 135b by the PSTN 128. The

Gateway MSC 127 queries the HLR 126 (signal 354) to determine the MSC/VLR location area 115 and the MSC 120 serving the MS 135b. The HLR 126 determines the MSC/VLR location area 115 and the serving MSC 120, and transmits a routing request (signal 355) to the serving MSC 120. The serving MSC 120 determines, to some selected degree of granularity, the location of MS 135b by paging the MS 135

(signal 356) and awaiting an acknowledgment (signal 357) from the MS. The MS 135 is in the paging mode during the phase where the serving MSC 120 pages the MS 135 and awaits acknowledgment. In accordance with a first embodiment of the present invention, the subscriber can preprogram the MS 135 to have the incoming call rerouted to a subscriber selected third party terminal 305c, responsive to receiving the page (signal 356).

Referring now to FIGURE 4A, there is illustrated a signal flow diagram describing the operation of the telecommunications network rerouting an incoming call responsive to paging the MS 135 (signal 356). In response to receiving the page (signal 356), the MS 135 causes the incoming call to be transferred to a third party terminal 305c by transmitting a transfer signal and a subscriber programmed C- number (signal 457) to the serving MSC 120 in response to the page (signal 356). The serving MSC 120 forwards the transfer signal and the C-number to the HLR 126 (signal 460) which forwards the transfer signal and the C-number to the gateway MSC 127 (signal 462). Upon receiving the transfer signal and the C-number, the gateway MSC 127 reroutes the call to the PSTN 128 (signal 465), which routes the call to the third party terminal 305c (signal 468).

Referring again to FIGURE 3 , if the subscriber has not preprogrammed the MS 135 to transfer the incoming calls responsive to receiving a page (signal 356), the MS 135 sends an acknowledgment (signal 357) to the serving MSC 120. The serving MSC 120 uses the acknowledgment to determine the location of the MS 135. I accordance with this determined location, the serving MSC 120 selects an appropriate routing number for that location and transmits (signal 358) the routing number to the HLR 126, which, in turn, transmits the routing number to the gateway MSC 127 (signal 359). The Gateway MSC 127 then routes the call to the serving MSC 120 (signal 362) which routes the call to a base station 150 (signal 365). The base station

150 transmits an alert message on a control channel (signal 368) to the MS 135. If the subscriber answers the incoming call, the MS 135 transmits an answer signal (signal 369) to the base station 150, and the base station establishes a voice connection on a traffic channel (signal 371). The phase when the base station 150 alerts the MS 135b is known as the alert mode, while the phase where a voice connection on a traffic channel exists is known as the voice mode. In accordance with the present invention, the subscriber can have the incoming call or pending call transferred to a third party terminal 305c by designating the directory phone number of the third party terminal 305c as the C-number and selecting the dynamic call transferring feature from the MS 135, while the MS 135 is in either the alert mode (between signals 368 and 371), or the voice mode (after signal 371).

Referring now to FIGURE 4B, there is illustrated a flow diagram describing the operation of the telecommunications network rerouting an incoming or pending call while the MS 135 is in either the alert mode or voice mode. Upon designating the C- number and selecting the dynamic call transferring feature, the MS 135b transmits a transfer signal and the C-number (signal 574) to the base station 150 which is forwarded to the MSC 120 (signal 577). Upon receiving the transfer signal and the C-number, the MSC 120 terminates trunk connections between the MSC 120 and the MS 135b and reroutes the call to the PSTN 128 (signal 580), which routes the call to the third party terminal 305c associated with the C-number (signal 583). In the foregoing embodiment, the MSC 120 reroutes the call to the third party terminal 305c, thereby allowing the subscriber to dynamically transfer incoming or pending calls at or after the call arrives. However, trunks between the Gateway MSC 127 and the MSC 120 and the MSC 120 and the PSTN 128 are unnecessarily used. To more efficiently utilize the available trunks, the MSC 120 forwards the C-number to the Gateway MSC 127, and the Gateway MSC 127 reroutes the call to the third party terminal 305c. In that manner, the unnecessary trunk connections between the Gateway MSC 127 and the MSC 120 and the MSC 120 and the PSTN 128 are avoided.

Referring now to FIGURE 4C, there is illustrated a flow diagram describing the operation of the telecommunications network rerouting the an incoming or pending call while the MS 135 is in either the alert mode or the voice mode, in accordance with an alternate embodiment of the present invention. Upon designating the C-number and selecting the dynamic call transferring feature, the MS 135b transmits a transfer signal and the C-number (signal 674) to the base station 150 which is forwarded to the MSC 120 (signal 677). Upon receiving the transfer signal and the

C-number, the MSC 120 terminates connections between the MSC 120 and the MS 135b. The MSC 120 then forwards the C-number to the Gateway MSC 127 (step 680). The C-number can be transferred to the gateway MSC 127 by the MSC 120 using, for example, a redirection request (REDREQ) message. Upon receiving the C- number, the Gateway MSC 127 terminates the trunk connection between the MSC 120 and the Gateway MSC 127, reroutes the call to the PSTN 128 (signal 683), which routes the call to the third party terminal 305c associated with the C-number (signal 686).

Although the invention has been described with a certain degree of particularity, it should be recognized that elements thereof may be altered by persons skilled in the art without departing from the spirit and scope of the invention. For example, although the description contained herein depicts embodiments of the invention in a GSM environment, it should be understood that other embodiments of the invention can practiced in other telecommunication network environments. Therefore, the invention is limited only by the following claims and their equivalents.

Claims

WHAT IS CLAIMED IS:

1. A mobile station for transferring a call between said mobile station served by a Public Land Mobile Network (PLMN) and a telephone terminal, to a third party terminal, said mobile station comprising: a transceiver for placing said mobile station in a paging mode with respect to said call; input means for receiving user inputs comprising an identifier identifying a third party terminal; and controller means responsive to said inputs for causing said transceiver to transmit a call transfer signal including the identifier after said transceiver places said mobile station in a paging mode, said call transfer signal causing said PLMN to transfer said call from said mobile station to a third party terminal.

2. The mobile station of claim 1 , further comprising: memory means for storing a plurality of identifiers, said identifiers identifying a plurality of third party terminals; and wherein said keypad receives user inputs causing said transceiver to transmit a signal and a select one of said plurality of identifiers stored in said memory means.

3. The mobile station of claim 1, wherein said controller means causes said transceiver to transmit a call transfer signal while said mobile station is in an alert mode.

4. The mobile station of claim 1, wherein said controller means causes said transceiver to transmit a call transfer signal while said mobile station is in a voice mode.

5. A method of transferring a call, said call between a telephone terminal and a mobile station, from said mobile station to a third party terminal, said method comprising the steps of: paging said mobile station; receiving a signal and an identifier from said mobile station, responsive to said step of paging said mobile station, said identifier identifying said third party terminal; and transferring said call to said third party terminal, responsive to said receiving step.

6. The method of claim 5, wherein said step of receiving further comprises the step of: receiving a signal and an identifier from said mobile station, said identifier comprising a directory phone number associated with said third party terminal.

7. A method of transferring a call, said call between a telephone terminal and a mobile station, from said mobile station to a third party terminal, said method comprising the steps of: placing said mobile station in an alert mode with respect to said call; receiving a signal and an identifier from said mobile station, after said step of placing said mobile station in an alert mode, said identifier identifying said third party terminal; and transferring said call from said mobile station to said third party terminal, responsive to said receiving step.

8. The method of claim 7, wherein said step of receiving further comprises the step of: receiving a signal and an identifier from said mobile station, said identifier comprising a directory phone number associated with said third party terminal.

9. The method of claim 7, wherein said step of transferring said call further comprises the steps of: establishing a phone call between said telephone terminal and said third party terminal.

10. The method of claim 7, wherein said step of placing said mobile station in an alert mode with respect to said call further comprises the steps of: establishing a first leg between a Public Switched Telephone Network (PSTN) and a mobile switching center (MSC) said MSC serving said mobile station; and establishing a second leg between said MSC and a base station, said base station serving said mobile station; and wherein said step of transferring said call further comprises: terminating said second leg between said MSC and said base station; establishing a third leg between said MSC and said PSTN; and establishing a fourth leg between said PSTN and said third party terminal.

11. The method of claim 7, wherein said step of placing said mobile station in an alert mode with respect to said call further comprises the steps of: o establishing a first leg between a Public Switched Telephone

Network (PSTN) and a gateway mobile switching center (MSC); and establishing a second leg between said gateway MSC and a serving MSC, said serving MSC serving said mobile station; establishing a third leg between said serving MSC and a base 5 station, said base station serving said mobile station; and wherein said step of transferring said call further comprises: terminating said second leg between said gateway MSC and said serving MSC; terminating said third leg between said MSC and said base station; establishing a fourth leg between said gateway MSC and said PSTN; and establishing a fifth leg between said PSTN and said third party terminal.

12. A wireless telecommunications system for transferring a call between a telephone terminal and a mobile station, said wireless telecommunications system comprising: a base station for establishing a call between said telephone terminal and said mobile station, wherein said base station receives, from said mobile station, a signal and an identifier associated with a third party terminal after establishing said call; and means for transferring said call from said mobile station to said third party terminal, after said base station establishes said call.

13. The wireless telecommunications system of claim 12, wherein said means for transferring further comprises a mobile switching center (MSC).

14. The wireless telecommunications system of claim 12, wherein said means for transferring further comprises a gateway MSC.

15. The wireless telecommunications system of claim 12, wherein said means for transferring further comprises means for transferring while said mobile station is operating in an alert mode.

16. The wireless telecommunications system of claim 12, wherein said means for transferring further comprises means for transferring while said mobile station is operating in a voice mode.

17. A method of transferring a call, said call between a telephone terminal and a mobile station, from said mobile station to a third party terminal, said method comprising the steps of: placing said mobile station in a voice mode with respect to said call; receiving a signal and an identifier from said mobile station, after said step of placing said mobile station in said voice mode, said identifier identifying said third party terminal; and transferring said call from said mobile station to said third party terminal, responsive to said receiving step.

18. The method of claim 17, wherein said step of receiving further comprises the step of: receiving a signal and an identifier from said mobile station, said identifier comprising a directory phone number associated with said third party terminal.

19. The method of claim 17, wherein said step of transferring said call further comprises the steps of: establishing a phone call between said telephone terminal and said third party terminal.

20. The method of claim 17, wherein said step of placing said mobile station in said voice mode with respect to said call further comprises the steps of: establishing a first leg between a Public Switched Telephone Network (PSTN) and a mobile switching center (MSC) said MSC serving said mobile station; and establishing a second leg between said MSC and a base station, said base station serving said mobile station; and wherein said step of transferring said call further comprises: terminating said second leg between said MSC and said base station; establishing a third leg between said MSC and said PSTN; and establishing a fourth leg between said PSTN and said third party terminal.

21. The method of claim 17, wherein said step of placing said mobile station in said voice mode with respect to said call further comprises the steps of: establishing a first leg between a Public Switched Telephone Network (PSTN) and a gateway mobile switching center (MSC); and establishing a second leg between said gateway MSC and a serving MSC, said serving MSC serving said mobile station; establishing a third leg between said serving MSC and a base station, said base station serving said mobile station; and wherein said step of transferring said call further comprises: terminating said second leg between said gateway MSC and said serving MSC; terminating said third leg between said MSC and said base station; establishing a fourth leg between said gateway MSC and said

PSTN; and establishing a fifth leg between said PSTN and said third party terminal.