Patent Publication Number: US-2003224722-A1

Title: Method of providing network-based wireless extension service

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
     [0001] The present application is related to application Ser. No. ______, entitled “METHOD OF PROVIDING WIRELESS-CONTROLLED WIRELESS EXTENSION SERVICE.” The above patent application is filed on the same day as the present application, assigned to the assignee of the present application, and incorporated by reference herein. 
    
    
     
       FIELD OF THE INVENTION  
       [0002] This invention relates generally to the field of wireless communication systems, and more particularly to utilizing wireless phones as extension phones for each other.  
       BACKGROUND OF THE INVENTION  
       [0003] Existing analog wireline extensions allow multiple wireline phones to be alerted by an incoming call. In addition, multiple of these wireline extensions can participate in a single call. One limitation to wireline extension phones is that once a phone is engaged in a call, the other phones can participate in the ongoing call but cannot participate in a different call.  
       [0004] In current wireless communication systems, no such extension capability exists. A call destined for a mobile station alerts only that station and only that station can participate in the session.  
       [0005] Therefore, a need exists for a method and apparatus that allows mobile stations to be simultaneously alerted when a call is destined for a member of the group. Further, a need exists for a method that allows multiple wireless phones to be involved in such a call. In addition, a need exists for a method that allows multiple mobile stations to participate in a single call.  
       BRIEF SUMMARY OF THE INVENTION  
       [0006] The present invention provides a method for providing extension functionality to multiple mobile stations. A plurality of mobile stations are associated together in an extension group as extension members. When a call is received for a mobile station that is an extension member, all mobile stations in the extension group are alerted. Each user can then decide to accept the call request and join the call or not accept the call request and therefore not join the call. In accordance with the present invention, each mobile station maintains its individuality and can initiate or receive calls without invoking the extension functionality. In an exemplary embodiment of the present invention, via the use of physical location of the mobile stations, only extension members within a certain geographical location are afforded extension functionality.  
       [0007] In accordance with an exemplary embodiment of the present invention, a network-based customer profile database stores a list of identities of the members of the extension group. These identities could be E.164 numbers or any other unique identifier. When a call arrives in the network for a mobile station with extension service enabled, the network engages a conference bridge. The conference bridge initiates a connection to each of the other mobile stations in the extension list. Mobile stations accepting the call are bridged onto the call.  
       [0008] Further, the network can do a location update on the extension members and only bridge the call to other extension members located within a predefined distance of the called mobile station. A unique alerting display is used at the extension mobile stations to indicate that this is an extension call and not a direct call to the extension mobile stations. Extension functionality can be disabled at each mobile station, thereby allowing completely independent operation.  
       [0009] Advantageously, such an arrangement gives mobile station users the functionality of extension phones and allows the mobile stations to also be used in an independent mode. 
     
    
    
     BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS  
     [0010]FIG. 1 depicts a communication system in accordance with an exemplary embodiment of the present invention.  
     [0011]FIG. 2 depicts a flow chart of a method for processing a call request in a network call control function in accordance with an exemplary embodiment of the present invention.  
     [0012]FIG. 3 depicts a flow chart of a method for processing a wireless extension query in a user profile data base in accordance with an exemplary embodiment of the present invention.  
     [0013]FIG. 4 depicts a flow chart of a method for processing a call request in the network conference bridging function in accordance with an exemplary embodiment of the present invention. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION  
     [0014]FIG. 1 depicts a communication system  100  in accordance with an exemplary embodiment of the present invention. In the exemplary embodiment depicted in FIG. 1, communication system  100  is a Third Generation (3G) wireless system. Communication system  100  can alternately be any digital cellular system. 3G wireless systems include multiple air interface standards, including cdma2000, Universal Mobile Telecommunications System (UMTS), Wideband CDMA (W-CDMA), Global System for Mobile Communications (GSM), and UWC-136, a TDMA-based technology.  
     [0015] As depicted in FIG. 1, communication system  100  depicts a 3GPP reference architecture of a UMTS wireless network. It should be understood that communication system  100  can alternately be other reference architectures. Communication system  100  includes logical elements that have been defined based on network functions that have been grouped together to form each logical element. Actual implementation may contain multiple copies of these logical elements within multiple networks, and can merge any of these logical elements into single hardware entities. The architecture of the exemplary embodiment of the present invention is designed to utilize emerging Internet standards and protocols. An example of this is the use of Session Initiation Protocol (SIP) for IP Multimedia Subsystem (IMS) signaling for establishing a call. Use of emerging internet-based protocols, such as IPv6, allows for the IMS to provide internet-like functionality and services to mobile units along with voice and data services.  
     [0016] Communication system  100  includes a plurality of logical elements, comprising User Equipment (UE)  112 , a Mobile Termination (MT)  113 , Radio Access Network (RAN)  121 , packet-switched domain  131 , IP Multimedia Subsystem (IMS)  141 , Charging Gateway Function (CGF)  134 , EIR  135 , and signaling gateway (SGW)  147 .  
     [0017] Both the UMTS-based and GSM/EDGE-based Radio Access Networks are shown in this figure. Charging Gateway Functionality (CGF)  134  is now part of the base 3GPP communication system  100  to show the collection of billing information in packet-switched domain  131 . As depicted in FIG. 1, Radio Access Network (RAN) and packet-switched domain  131  are independent of IMS  141 .  
     [0018] User equipment can be any device or combination of devices that can be used to connect with a wireless network. User Equipment, for example, can be comprised of User Equipment (UE)  112  and a Mobile Termination (MT)  113 . User equipment is preferably a 3G mobile station that communicates with communication system  100  via an air interface supported by communication system  100 .  
     [0019] RAN  121  is preferably a UMTS Terrestrial Radio Access Network (UTRAN), which is the primary interface between the wireless device and the UMTS access network. Alternately, RAN  121  can be a GSM/EDGE Radio Access Network (GERAN), which is the primary interface between the wireless device and the GSM/EDGE access network. RAN  121  is coupled to the user equipment via an air interface, such as a 3G air interface.  
     [0020] Packet-switched domain  131  includes Serving GPRS Support Node (SGSN)  132  and GPRS Gateway Support Node (GGSN)  133 . SGSN  132  provides packet mobility management, authentication, session management, accounting, mapping of IP addresses to user equipment identification, such as IMSI, maintenance of mobile state information, and interfacing with GGSN  133 . GGSN  133  provides interworking between the SGSNs and external packet data networks using IP.  
     [0021] IMS  141  preferably includes Call State Control Function (CSCF)  143 , Breakout Gateway Control Function (BGCF)  144 , Media Gateway Control Function (MGCF)  145 , Media Gateway (MGW)  148 , and Multimedia Resource Function (MRF)  149 .  
     [0022] CSCF  143  is a signaling entity for bearer/session control. CSCF  143  manages SIP sessions, provides features/services and coordinates with other network elements for session control, feature/service control and resource allocation.  
     [0023] CSCF  143  performs multiple functions, which in an exemplary embodiment include incoming call gateway, call control function, serving profile database, and address handling. In addition, in accordance with an exemplary embodiment of the present invention, CSCF  143  performs the network call control function for wireless extension functionality.  
     [0024] CSCF  143  has interfaces with many network elements, preferably as defined by the Third Generation Partnership Project standards, in standards document 3GPP TS 23.002. CSCF  143  is preferably connected to a plurality of elements using the SIP protocol. These network elements include GGSN  133  via interface Gi, MT  113  using interface Gm (not shown), MGCF  145  using interface Mg, BGCF  144  using interface Mi, MRF  149  using interface Mr, IP Multimedia Domain  175  (not shown), and other CSCFs, such as CSCF  193 , using interfaces Mw. CSCF  143  is coupled with HSS  142  via interface Cx, preferably using the DIAMETER protocol. In addition, in accordance with an exemplary embodiment of the present invention, HSS  142  performs the User Profile Data Base function for wireless extension functionality. CSCF  143  is coupled to SGW  147  via interface Ms, which preferably uses a MAP protocol, but can alternately use a CAP or other SS7 application protocol.  
     [0025] BGCF  144  is a signaling entity for bearer/session control. The primary responsibility of BGCF  144  is to select the network to use for inter-working with PSTN  161  for a call from MT  113  to a PSTN address. BGCF  144  preferably performs additional functions, which include but are not limited to selection of the appropriate MGCF, hiding of network information from other networks, and provision of security through authorization of peer network elements.  
     [0026] BGCF  144  communicates with CSCF  143  via Mi interface, with MGCF  145  via Mj interface, and with BGCF  194  via Mk interface. These interfaces are defined in 3GPP TS 23.002. SIP is the preferred protocol for these standard interfaces. BGCF  144  may also have interfaces with other entities (not shown) to assist in making decisions within communication system  100 .  
     [0027] BGCF  144  is preferably a logical entity from the 3GPP reference model. The actual implementation of BGCF  144  may be combined on the same platform with other logical entities that perform signaling functions such as CSCF  143 , MGCF  145 , and SGW  147 .  
     [0028] To select a PSTN gateway, BGCF  144  in the home network receives the call origination message, which is an exemplary embodiment is a SIP INVITE message, from CSCF  143 . The receipt of a call origination message from CSCF  143  indicates that the destination is a PSTN address. BGCF  144  needs to determine which network should be used to provide inter-working with PSTN  161 . BGCF  144  may use data from multiple sources to make this determination. Examples of factors which BGCF  144  may look at in making this determination include, but are not limited to, the current location of the calling UE, the location of the PSTN address, local policies and business agreements between the visited and home networks, the desire to minimize path distance within the PSTN network, and a desire for the least-cost path. If the PSTN gateway is decided to be the home network, an MGCF within the home network, such as MGCF  145 , will be selected. If the PSTN gateway is decided to be at another network, the BGCF address for the other network must be determined so that the processing may be forwarded to that network.  
     [0029] BGCF  144  may also provide information hiding functionality. When two BGCFs are used across a network boundary, then the BGCFs may be used to hide local network information from the other network. BGCF  144  can also provide security in communication system  100 . BGCF  144  provides security by performing authorization of peer network elements for peer-to-peer SIP application level communication.  
     [0030] MGCF  145  terminates signaling and provides the call control interface and translations between IMS  141  and PSTN  161 . MGCF  145  also provides connection control for the media channels in MGW  148 . MGCF  145  communicates with MGW  148  via the Mc interface, with BGCF  144  via the Mj interface, and with CSCF  143  via the Mg interface.  
     [0031] MGCF  145  also preferably provides signaling to control a set of Media Gateways (MGW), such as MGW  148 . This signaling is preferably in the form of H.248. With H.248, MGCF  145  is able to control establishment of bearer resources for sessions that require inter-working for bearer between PSTN  161  and IMS  141 . For calls that require the services of a network operator&#39;s MGW, ports are allocated via requests from MGCF  145  within that network operator&#39;s network.  
     [0032] Signaling allows MGCF  145  to perform multiple operations with respect to MGW  148 . These operations include MGW registration, bearer establishment control between IMS  141  and PSTN  161 , request for allocation of media translation resources (i.e., compression, echo cancellation, vocoding, etc.), control of events detected at MGW  148 , application of signals such as tones and announcements by MGW  148 , and collection of statistics.  
     [0033] MGCF  145  preferably controls multiple MGWs. To be placed into service, the MGWs register themselves with their default MGCF. After registration with an MGCF, MGWs can begin bearer processing.  
     [0034] MGCF  145  preferably implements a SIP-based interface to CSCF  143 . BGCF  144  may be in the signaling path between CSCF  143  and MGCF  145 . Using this interface, MGCF  145  accepts commands from CSCF  143  to perform functions related to the control of a call.  
     [0035] MGW  148  is the element that translates between a media flow, such as voice, on a given IP network and bearer data on PSTN  161 . MGW  148  terminates circuit-switched bearer traffic from PSTN  161  and terminates IP media flow as packet streams through GGSN  133  or MGW  173 , eventually reaching the user equipment. MGW  148  preferably performs vocoding and may also provide tones and announcements. If in-band signaling methods are supported at MGW  148 , then for PSTN traffic using in-band signaling, MGW  148  preferably terminates both bearer and signaling traffic, and forwards the signaling messages to MGCF  145 . MGW  148  interfaces with GGSN  133  via the Gi interface and with MGCF  145  via the Mc interface.  
     [0036] MGW  148  may include resources to modify a bearer stream. These resources allow MGW  148  to perform encoding, compression, echo cancellation, packetization, transcoding, packet timing synchronization, and packet loss handling.  
     [0037] MGW  148  preferably supports multiple types of voice encoding. These include, but are not limited to, G.711, Adaptive Multi-Rate (AMR), and other G.7xx encoding schemes. MGW  148  is preferably able to use G.711 to encode and decode voice on trunks connected to a PSTN network.  
     [0038] MGW  148  preferably organizes bearer connections using H.248 contexts containing terminations. MGW  148  may include numerous simultaneous contexts.  
     [0039] MGW  148  also preferably includes resources to support a plurality of signaling mechanisms, including but not limited to registration with MGCF  145 , detection of events (e.g. Dual-Tone Multi-Frequency (DTMF) detection), application of tones and announcements to bearer streams, graceful teardown and random restart, notification, generation of statistics, and support of H.248 packages.  
     [0040] MRF  149  provides packet-based media services, such as advanced announcement generation and detection, N-way conferencing, tone and announcement generation, and future advanced media services, such as video mixing. In addition, in accordance with an exemplary embodiment of the present invention, MRF  149  performs the network conference bridge function for wireless extension functionality. MRF  149  also preferably provides transcoding and interactive voice response. MRF  149  interfaces with CSCF  143  via the Mr interface, with IP Multimedia Domain  175  (not shown), and with GGSN  133  via the Gi interface.  
     [0041] In an exemplary embodiment of the present invention, MRF  149  comprises two parts, a controller part and a bearer part. CSCF  143  preferably interfaces with the MRF controller part to request media services using SIP. The controller part preferably communicates with the bearer part via H.248. The bearer part preferably supports RTP/UDP/IP. Some of the resources maintained by MRF  149  include vocoders, transcoders, compression entities, bearer-stream mixers, echo cancellors, and other DSP resources. Vocoders are needed at MRF  149  for transcoding and mixing of multimedia streams.  
     [0042] HSS  142  provides support for subscriber authentication, subscriber profile management, service authorization, subscriber location management, inter-system handover, and call routing. HSS  142  provides these functions for users receiving service from circuit-switched domain  151 , packet-switched domain  131 , and IMS  141 .  
     [0043] HSS  142  preferably maintains a subscriber database that includes information including, but not limited to, the identity of the subscriber, services and associated policies, location, and authentication data.  
     [0044] HSS  142  supports the following interfaces. Interface Cx is the interface to CSCF  143 . The preferred protocol for this interface is DIAMETER. Interface Mh is the interface to SGW  147 . Interface Gr is the interface to SGSN  132 . Interface Gc is the interface to GGSN  133 . Interface C is the interface to GMSC server  153 . Interfaces Mh, Gr, Gc, D and C preferably utilize a MAP protocol.  
     [0045] In accordance with an exemplary embodiment of the present invention, HSS  142  recognizes when features and services are to be implemented for a subscriber at either MSC server  152  or IMS  141 . In addition, HSS  142  supports procedures for IMS-homed mobile units being served at a remote MSC Server.  
     [0046] SGW  147  terminates transport protocols for signaling between PS domain  113  and IMS  141 . The services of SGW  147  are preferably used to ensure transport interworking between the SS7 and the IP transport of signaling on its various interfaces (not all shown). SGW  147  communicates with CSCF  143  and HSS  142  via the Ms and mh interfaces, respectively.  
     [0047] SGW  147  provides for HSS Subscriber roaming into circuit-switched wireless networks and transport of circuit-switched signaling over IP, such as TCP/IP.  
     [0048]FIG. 2 depicts a flow chart  200  of a method for processing a call request in network call control function  143  in accordance with an exemplary embodiment of the present invention. Network call control function  143  receives ( 201 ) an incoming call request. The incoming call request can be for a voice, data, or multimedia call.  
     [0049] Network call control function  143  initiates ( 202 ) a query to user profile data base  142 . The query is intended to determine if the called number has the wireless extension functionality enabled. The processing that occurs at user profile database  142  is depicted in FIG. 3.  
     [0050] Turning now to FIG. 3, FIG. 3 depicts a flowchart  300  of a method for processing in user profile data base  142  a wireless extension query in accordance with an exemplary embodiment of the present invention. User profile data base  142  receives ( 301 ) the query from network call control function  143 . The query preferably includes an indication, such as the directory number, of the called mobile station.  
     [0051] User profile data base  142  accesses ( 302 ) a user profile entry associated with the called mobile station. The user profile entry preferably includes a field that indicates whether the wireless extension feature is enabled or disabled and a list of the mobile stations that are members of the extension group. The list can be, for example, a linked list of the directory numbers of all members of the extension group.  
     [0052] User profile data base  142  formulates and returns ( 303 ) a query response to network call control function  143 . The query response includes selected data from the user profile, preferably whether wireless extension functionality is enabled. If wireless extension functionality is enabled, the query response includes a list including all extension group members. The process then ends ( 399 ).  
     [0053] Returning now to FIG. 2, network call control function  143  accepts ( 203 ) the query response from user profile data base  142 . Network call control function  143  determines ( 204 ) if the called mobile station has the wireless extension service enabled. In an exemplary embodiment, network call control function  143  determines if the called mobile station has wireless extension functionality enabled by determining if user profile data base  142  has returned a list that includes at least one other representation of another mobile station. In a further exemplary embodiment, network call control function  143  determines if the called mobile station has wireless extension functionality enabled by checking whether the field indicating whether the wireless extension functionality is enabled or disabled.  
     [0054] If the called mobile station does not have wireless extension service enabled as determined at step  204 , network call control function  143  completes ( 205 ) the call normally. The processing then ends ( 299 ).  
     [0055] In one embodiment of the present invention, wireless extension members will only be alerted to the new call request if they are within a predetermined distance from the called mobile station. In this embodiment, if the called mobile station has wireless extension service enabled as determined at step  204 , network call control function  143  determines ( 206 ) the geographical location of the mobile stations on the wireless extension list. Network call control function  143  only includes wireless extension members that are located within a predetermined geographical area in the wireless extension service for this call request. The mobile station user can set the geographical area through means currently used to set network options, such as via touch pad entries as used for user screen list editing. The location of the mobile stations on the list can be determined by the network call control function  143  using techniques such as cell and sector, time of arrival, and other similar location-finding techniques. These techniques rely on cooperation of elements such as the Radio Access Network (RAN)  121 .  
     [0056] An exemplary embodiment of the present invention includes determination of the locations of the mobile phones in the extension list. Without loss of generality or functionality, the called mobile station can, via existing means, request that the location step be bypassed. An exemplary method of effectively bypassing this step is to set the predetermined geographic region to any area larger than that covered by the communication system, so that all mobile stations in the extension list will be paged.  
     [0057] The following are three representative examples of the use of geographical information used in extension functionality. First, extension service can be offered to mobile stations on a corporate campus. That is, only mobile stations within a predetermined distance from the workplace at a given time would be offered extension service. A second example is when all mobile stations located within a predetermined distance from a residence are offered extension service. In this way personal calls can be shared among mobile stations at the residence without interrupting mobile stations away from the residence. Finally, there can be no geographical limitations at all. All mobiles in the extension list are alerted.  
     [0058] Network call control function  143  requests ( 207 ) the network conference bridge  149  to setup a multiparty call to the mobile stations in the wireless extension group that are in the geographic location. The processing that occurs in the network bridging function is depicted in FIG. 4 below. The process then ends ( 299 ).  
     [0059] Turning to FIG. 4, FIG. 4 depicts a flowchart  400  of a method for processing in network conference bridging function  149  the call request in accordance with an exemplary embodiment of the present invention. Network conference bridging function  149  receives ( 401 ) a multiparty call request.  
     [0060] Network bridging function completes ( 402 ) the multiparty call to all specified mobiles answering the multiparty call. This is accomplished by alerting the mobile stations specified in the multiparty call request and waiting a predetermined time for those mobile stations to respond to the alerting. Mobile stations not responding are not bridged onto the call. If no mobile stations respond, normal call processing occurs between the calling phone and the called mobile station.  
     [0061] Bridging then occurs between the calling phone, the called mobile station, and all extension group members that have responded affirmatively to the call request. When the multiparty call has ended, network conference bridging function  149  releases ( 403 ) the conference bridge. The process then ends ( 499 ).  
     [0062] The present invention thereby provides a method for providing extension capabilities to wireless mobile stations. By using the present invention, a user can be given the same functionality as is available with wireline extension phones. Prior art does not support this functionality for mobile phones. When coupled with the ability of determining the geographical location of other mobile stations, multiple benefits are recognized. These include employee group members located at a corporate campus being alerted to an incoming call; family members located at or near the residence being alerted to an incoming call; or no geographical limitation being imposed on the alerting all extension group members. Individual extension list members can decide not to join the extension call and continue to use the mobile station in an independent manner.  
     [0063] While this invention has been described in terms of certain examples thereof, it is not intended that it be limited to the above description, but rather only to the extent set forth in the claims that follow.