Hand-out and hand-in support for legacy mobiles serviced by a femtocell attached to an IMS network

The present disclosure is directed to a system and method configured to implement an inter-MSC based handoff of a mobile device between a packet switched network and a mobile core network. In embodiments implementing a handoff from a femtocell to a macrocell, from the perspective of a neighboring MSC on a mobile core network, IP or VOIP information from a femtocell which is in communication with the convergence server, is perceived as having the same protocol as information which originates from a macrocell. Inversely, in embodiments implementing a hand-in to the femtocell from a macrocell, information which originates from a macrocell, which is in communication with the convergence server, would be perceived as IP or VOIP code to the femtocell. Accordingly, a target MSC in a handoff is agnostic of the fact that the mobile device entering into the macrocell was actually attached to a femtocell. Thus, embodiments of the present invention allow existing inter-MSC based handoff solutions to be leveraged.

TECHNICAL FIELD

The following description relates generally to mobile device communication and, more particularly, to providing for effective handoff transitions of communications between wireless access points of packet switched networks and wireless access points of mobile core networks.

BACKGROUND OF THE INVENTION

Communication has become an ever increasing part of day-to-day life, both in business and personal lives. Accordingly, various forms of communication devices have become nearly ubiquitous. For example, a very large portion of the world's population have and utilize mobile devices, such as cellular telephones, personal communication system (PCS) phones, personal digital assistants (PDAs), smart phones, personal computers (PCs), etc., to provide voice and/or data communication. To provide highly mobile operation, such mobile devices often operate wirelessly to communicate with a host network. Thus, the mobile devices may be, for example, portable, pocket, hand-held, computer-included, or car-mounted devices which communicate voice and/or data wirelessly via a host radio network. Of course, such mobile devices can be fixed mobile devices, e.g., fixed cellular devices/terminals which are part of a wireless local loop or the like.

Cellular networks are well known for providing communications with respect to various mobile devices. In a typical cellular network, mobile devices communicate via a radio access network (RAN) to devices coupled to the cellular network. The RAN traditionally covers a geographical area which is divided into cell areas, with each cell area being served by a base station. The area coverage of such a base station, or cell area, is sometimes referred to as a macrocell. The base stations communicate over an air interface (e.g., radio frequencies) with the mobile devices or other mobile devices within range of the base stations. These base stations are typically positioned to bring the greatest coverage to the greatest number of cellular telephone users.

In the RAN, several base stations are typically connected (e.g., by landlines or microwave) to a radio network controller (RNC). The RNC, also sometimes termed a base station controller (BSC), supervises and coordinates various activities of the plural base stations connected thereto. The RNCs are typically connected to one or more systems (e.g., a mobile switching center (MSC)) providing the core communication services (e.g., call connect, call accounting, enhanced telephony services (ETSs) such as voice mail, one number service, call back service, language translation, call waiting, three-way calling, caller ID, do not disturb, and call forwarding service, public switched telephone network (PSTN) interfacing, etc.).

One example of a RAN is the universal mobile telecommunications (UMTS) terrestrial radio access network (UTRAN). The UMTS is a third generation system which in some respects builds upon the radio access technology known as global system for mobile (GSM) developed in Europe. UTRAN is essentially a RAN providing wideband code division multiple access (WCDMA) to mobile devices. Other types of cellular telecommunications systems which encompass RANs include, but are not limited to GSM systems, advance mobile phone service (AMPS) systems, narrowband AMPS (NAMPS) systems, total access communications system (TACS) systems, personal digital cellular (PDC) systems, United States digital cellular (USDC) systems, and code division multiple access (CDMA) systems (e.g., as described in EIA/TIA IS-95).

Cellular networks such as those described above are referred to herein as a “mobile core network” (or simply “mobile core”) and typically provide a circuit switched network. It should be appreciated that, although terms typically associated with particular network standards and protocols have been used in describing exemplary mobile core networks above, mobile core networks as discussed herein may comprise various configurations, such as GSM, CDMA, time division multiple access (TDMA), UMTS, second generation (2G), third generation (3G), high speed packet access (HSPA), time division-synchronous code division multiple access (TD-SCDMA), time division-code division multiple access (TD-CDMA), etc. The makeup and functionality of these and other mobile core networks is well-known in the art and is thus not described further herein.

It should be appreciated that, in a traditional cellular network, the coverage of the macrocell base stations is often not uniform. For example, individual buildings (e.g., homes, offices, etc.) may have weak signals indoors. Accordingly, more recently the addition of femtocell base stations (sometimes referred to as “home base stations,” “access point base stations,” “3G access points,” “small cellular base stations,” and “personal 2G-3G base stations”) has evolved.

In general, a femtocell base station is a small cellular base station designed for use in residential or small business environments. It connects to the service provider's network via a broadband packet switched network (such as using digital subscriber line (DSL), asymmetric digital subscriber line (ADSL), or cable internet) and typically supports 1 to 5 mobile devices (e.g., telephones) in a residential or business setting. In general, the femtocell incorporates the functionality of a typical base station but extends it to allow a simpler, self-contained deployment.

A femtocell base station allows service providers to extend service coverage within a targeted small geographic location, such as within a user's home or business—especially where access would otherwise be limited or unavailable—without the need for an expensive traditional cellular base station to be added to provide communication services for use by a small number of mobile devices. That is, although there may be hundreds or thousands of areas in which the mobile core network does not provide adequate coverage for communication services, each such area may have a very few mobile devices operated therein. Deploying a relatively small and inexpensive femtocell base station, leveraging a readily available broadband packet switched network such as the Internet to provide a communication link to the mobile core network, facilitates economic mobile device communications within these areas otherwise unserved or inadequately served by traditional macrocell base stations.

A femtocell base station may thus be deployed directly within a wireless subscriber's premises, such at a home or office. With a femtocell base station, the wireless communication device (e.g., cellular telephone) accesses the femtocell base station through traditional licensed spectrum. However, using such femtocell base stations, connectivity to the mobile core network is provided through the packet switched network using voice over internet protocol (VoIP) and/or internet protocol multimedia subsystem (IMS) technologies.

As can be appreciated from the foregoing, communication protocols and processing paths that are used in a network implementing a packet switched network (e.g. a femtocell), are different than those traditionally used for communication with the mobile core network. As a result, difficulties arise when a mobile device attempts to hand-in or hand-out between a femtocell and a macrocell.

Current solutions deployed in the market to address hand-in/hand-out difficulties do not support a hand-in to the femtocell network from a macrocell network, or a hand-out of the femtocell network to a macrocell network, while a mobile device is on an active call. As a result, an ongoing active call will be dropped either when a user is coming into the femtocell or leaving the femtocell.

One proposed solution to enable hand-in and hand-out of a mobile device during an active call is a voice call continuity (VCC) based approach. VCC approaches require mobile devices to be able to support concurrent calls on a mobile core network and on a packet switched network. Because the VCC based approach forces the mobile device to use its resources to support a redundant connection on two networks, needless overhead is created and devices must possess additional functionality to enable them to communicate on both networks simultaneously. In other words, mobile devices implementing a VCC approach can not be legacy devices (e.g. mobile devices adapted for mobile core network communications without specific adaptation for such communications to be provided via a packet switched network). Another limitation of the VCC solution is that in order to seamlessly hand off a call, the call must always be routed through a VCC server due to the inability to predict when a mobile device will enter or exit a femtocell or macrocell. As a result, even on a call that is between devices that are transmitting solely on a mobile core network, the call must be routed through the VCC server, thereby inserting inefficiency.

Another issue that results from differing protocols used in networks implementing a femtocell and those traditionally used for communication with a mobile core network is apparent when attempting to identify users within the different networks. In a packet switched network, or especially in an IMS network, users are often identified using a session initiation protocol (SIP) identifier or other identifier, which is similar to an email address (e.g. user@IMS.Tatara.com). Whereas in a mobile core network, users are typically identified using an MDN, which is a 10-digit mobile number. A packet switched network is not aware of the MDN and a mobile core network is not aware of the packet switched network public user identity. This introduces a problem because a user gets registered in the packet switched domain using the public user identity, whereas the real identity of that macro user is the MDN. So moving forward, if the carrier wants to handoff of the packet switched network's services, then it would need to know the MDN of the user.

Currently, if the MDN of the user is not known, in order to allow handoff of the packet switched network's services, the information must be downloaded from a visitor location register (VLR). So there is a disconnect between the databases of the differing networks. Another problem is if a user that is subscribed to an access point in a packet switched network (e.g. a femtocell) has moved onto another service provider network, for example from Sprint to Verizon, then the subscriber would need to be deleted from two separate databases, the home location register (HLR) database, and the home subscriber server (HSS) database. Therefore, currently there are two databases that need to be maintained for a femtocell subscriber being served.

BRIEF SUMMARY OF THE INVENTION

The present invention is directed to a system and method configured to implement an inter-MSC based handoff of a mobile device between a packet switched network and a mobile core network. In embodiments implementing a handoff from a packet switched network to a mobile core, from the perspective of a neighboring MSC on a mobile core network, information received from the packet switched network is perceived as having the same protocol as information which originates from the mobile core network. Inversely, in embodiments implementing a hand-in to the packet switched network from the mobile core network, information which originates from a mobile core network would be perceived having the same protocol as information in a packet switched network. Accordingly, a target MSC in a handoff is agnostic of the fact that the mobile device entering into the mobile core network was actually attached to a packet switched network. Thus, embodiments of the present invention allow existing inter-MSC based handoff solutions to be leveraged as opposed to a VCC method of doing a handoff.

Additionally, embodiments are configured to execute a handoff is without requiring the mobile device to simultaneously broadcast using two protocols. Further, embodiments provide for a seamless handoff between networks, even during active voice calls.

Some embodiments implement an inter-MSC based handoff of a mobile device between a packet switched network and a mobile core network by utilizing a convergence server. Such a convergence server is configured to communicate with, and gather information from, devices in the mobile core network. Using this information and communication abilities, the convergence server is able to communicate with the mobile core network in a manner which makes the convergence server appear to be an MSC. Hence, known inter-MSC based handoff techniques are able to be implemented between the mobile core network and the packet switched network.

Embodiments are also configured to manipulate communication trunks. For example, once a phone is handed off to the mobile core network, the communication path that was established with a femtocell will be diverted to the target MSC. Since aspects of the packet switched network may not have a dedicated media gateway server, embodiments of the present invention provide for a system, such as a convergence server, that is configured to manipulate a media server that is already in the path of the call. Using an existing media server to do the handoff and have the traffic diverted to the target MSC reduces the cost of the overall solution because the it allows the system to leverage existing media servers.

Embodiments may also function to assist in the identification and registration users entering areas which utilize different protocols. For example, a convergence server may be utilized identify new users and to notify relevant databases of the identifiers of a new user which are used separate networks. In this manner, networks that handle users that have multiple identifiers, for example an MDN and an SIP identity, are able to more efficiently hand off such users.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1shows communication system100adapted according to an embodiment of the invention. Communication system100of the illustrated embodiment includes femtocell base station110coupled mobile core network130via packet switched network120. Communication system100is operable to provide for an inter-MSC based handoff between a macrocell and a femtocell for communication devices, such as mobile devices101and102which are on an active call and have need to hand-in/hand-out of the respective networks. As will be appreciated from the description of embodiments below, facilitating hand-in or a hand-out according to embodiments may be accomplished without modification to the legacy communication devices or mobile core network130.

Mobile devices101and102of the illustrated embodiment may comprise various configurations of communication devices. For example, mobile devices101and102may comprise cellular telephones, personal communication system (PCS) phones, personal digital assistants (PDAs) (e.g., the BLACKBERRY device available from Research In Motion), smart phones, personal computers (PCs), etc., operable to provide voice and/or data communication. Mobile devices101and102are referenced herein as legacy communication devices in order to describe concepts of the present invention. It should be appreciated, however, that communication system100, including femtocell base station110, may accommodate both legacy communication devices and non-legacy communication devices (e.g., communication devices which convert cellular signals to SIP and interfaces to a SIP-MSC inter-working function (IWF) which connects to the SIP (or IMS) network as well as the circuit-switched network).

Mobile core network130is adapted to provide communication services (e.g., cellular telephony service, short message service (SMS), general packet radio service (GPRS), multimedia broadcast service, etc.) to various communication devices, such as mobile devices101and102. Specifically, mobile core network130of the illustrated embodiment includes systems, data, and interconnections providing a radio access network (RAN) for providing communication services to various communication devices. Accordingly, mobile core network130is shown to include base station132for communicating over an air interface (e.g., radio frequencies) with the mobile devices or other mobile devices within range (within the macrocell area) of the base station. Mobile core network130is additionally shown to include home location register (HLR)131, such as may comprise a database of information (e.g., international mobile subscriber identity (IMSI), mobile subscriber integrated services digital network number (MSISDN), services enabled for the mobile device, settings to allow the mobile device to access packet services, visitor location register (VLR), serving GPRS support node (SGSN), enhanced telephony services (ETSs) settings, etc.) for each mobile device that is authorized to use mobile core network130.

Mobile core network130may comprise additional or alternative systems, data, and interconnections. For example, embodiments of mobile core network130will typically comprise a large number of base stations connected (e.g., by landlines or microwave) to radio network controllers (RNCs) or base station controllers (BSCs)133. Additionally, mobile core network130may comprise a mobile switching center (MSC)134communatively coupled to the RNCs/BSCs133and providing the core communication services. Mobile core network130of embodiments will typically be coupled to the public switched telephone network (PSTN) (not shown) so as to facilitate communications between mobile devices and devices coupled to the PSTN, including mobile devices of other mobile core networks also coupled to the PSTN.

General operation of a mobile core network, such as mobile core network130, in providing communication services to a plurality of communication devices is well known and will not be discussed in detail herein. It should be appreciated, however, that the coverage areas provided by base stations (e.g., base station132) of mobile core network130may not provide adequate coverage of all areas in which users wish to operate mobile devices for communication services. For example, coverage gaps, coverage shadows, etc. may exist in various areas, such as within a building, on the far side of a mountain or other terrain, etc. Likewise, coverage may not be provided in certain areas, such as in rural areas, beyond the physical service limits of the service provider, etc. Accordingly, femtocell base stations, such as femtocell base station110, is utilized to provide communication services within areas otherwise not serviced or inadequately serviced by mobile core network130.

Femtocell base station110of the illustrated embodiment comprises a small base station providing operation mimicking or emulating that of a base station, such as base station132, of mobile core network130. That is, femtocell base station110provides an air interface to mobile devices, such as mobile device101, which functions the same as the air interface provided by a typical base station of mobile core network130(e.g., utilizes frequencies, channels, protocols, etc. native to the mobile core network), albeit at perhaps lower transmission power due to the typically smaller size of the femtocell coverage area. For example, femtocell base station110may comprise a universal mobile telecommunications (UMTS) configured base station containing a Node B, RNC and general packet radio service support node (GSN) with Ethernet for backhaul through packet switched network120. Additionally or alternatively, femtocell base station110may comprise a configuration compatable with other communications solutions, such as GSM, CDMA2000, TD-SCDMA, and/or WiMAX.

The illustrated embodiment of femtocell base station110connects to mobile core network130via packet switched network120. For example, femtocell base station110may utilize a digital subscriber line (DSL), asymmetric digital subscriber line (ADSL), or cable internet connection available at its deployment location to connect to packet switched network120. Connectivity to mobile core network130may be provided through packet switched network120using such technologies as voice over internet protocol (VoIP), internet protocol multimedia subsystem (IMS), etc. Accordingly, femtocell base station110of embodiments may utilize various architectures, such as a SIP/IMS, based architecture or an IP RAN based architecture.

Packet switched network120of the illustrated embodiment comprises a broadband packet switched network providing information communication supporting digitized data exchange suitable for communication links between mobile devices, such as mobile device101, and other devices, such as mobile device102, devices coupled to the PSTN (not shown), devices coupled to packet switched network120, etc. Accordingly, packet switched network120of the illustrated embodiment comprises packet data gateway/packet data information function (PDG/PDIF)121, authentication, authorization, and accounting (AAA) server122, convergence server123, and media server124operable to facilitate communications according to embodiments of the invention.

PDG/PDIF121of embodiments provides a packet switched network data gateway facilitating data packet communication between devices, such as femtocell base station110, and other devices of packet switched network120. For example, PDG/PDIF121may provide interfacing, link security, protocol conversion, data packet routing, and/or other functions for network edge devices, such as femtocell base station110.

AAA server122of embodiments provides centralized access, authorization and accounting management for devices to connect and use a network service of packet switched network120. For example, AAA server122may implement internet protocol secuirty (Ipsec) protocols for establishing mutual authentication, negotiation of cryptographic keys to be used during a communication session, etc.

Media server124of embodiments provides media content arbitration between mobile core network130and devices coupled to packet switched network120. For example, media server124may facilitate voice, video, and/or other media links between mobile core network130and mobile device101by accommodating the different protocols of mobile core network130and packet switched network120.

Convergence server123of embodiments of the present invention provides interfacing between packet switched network120and mobile core network130which facilitates in providing the communication services of mobile core network130to mobile devices, such as mobile device101, coupled to mobile core network130via packet switched network120. For example, convergence server123of embodiments facilitates the hand-in/hand-out of legacy mobile devices on active calls which have need of transitioning between femtocell110and a macrocell supported by base station132. Convergence server123of embodiments may provide control with respect to various systems and devices, such as femtocell base station110, PDG/PDIF121, AAA sever122, media server124, etc., to provide operation as described herein.

Convergence server123of embodiments further operates to provide functionality of a MSC for base stations (e.g., femtocell base station110) coupled through packet switched network120. Accordingly, convergence server123interacts with mobile core network130, and other communication core networks (e.g., other mobile core networks, the PSTN, etc.), as a MSC to facilitate call setup, and other communications consistent with the communication protocols of such communications networks. Additionally, because convergence server123contains the functionality of an MSC, mobile devices101and102are able to seamlessly be handed between the protocols of core network130and packet switched network120. This is also done without dropping the respective active calls, and without requiring mobile devices101and102to broadcast simultaneous calls on core network130and packet switched network120.

Embodiments may also function to identify and register users entering areas which utilize different protocols. When a user, such as mobile device101is registered in the packet switched network, a third party registration is initiated to convergence server123which notifies convergence server123of the public user identity of that mobile device101that has been assigned on the packet switched network. A user registration is also implemented on HLR131using information from mobile device101. Upon a successful registration and authentication in the HLR131, the MDN of mobile device101, which may be a 10-digit mobile identity number on the mobile core network130, is downloaded to convergence server123. At this point in time, convergence server123can notify a HSS (not shown), or AAA122, of the association between the public user identity on the packet switched network, and the MDN identity of the subscriber. Convergence server123may also create a database association of the two different identities so that if future packet switched network services need to be provided to the mobile device when it is on the mobile core network, the packet switched network access the HSS and retrieve any information required for services, as opposed requesting that the convergence server get the information.

FIG. 2shows a high level flow diagram200of an exemplary hand-out routine wherein a mobile device is connected on an active call on a packet switched network, and is attempting to transition to a mobile core network. When mobile device101starts moving away from a packet switched network's access point, such as femtocell110, mobile device101recognizes that a handoff is desired because, for example, the signal strength for a different base station is higher than that of femtocell110, and therefore it initiates a handoff request to the femtocell110. Femtocell110encapsulates information from the request and sends it to source MSC201, in handoff request message202. It is noted that in some embodiments, source MSC201may be implemented by convergence server123. Source MSC201sends a request to media server124for to assign a new circuit ID203. Since a convergence server, or source MSC201, may not have a dedicated media gateway, embodiments may use media server124to establish a communication path. The circuit ID contains routing information corresponding to the communication path (e.g. the current availability of the path) which will be established after the handoff is complete. Media gateway server124responds to request203and notifies source MSC201of the new circuit ID204. It is noted that request203and notification204may be implemented by using a SIP request. SIP protocol may be advantageous because it alleviates the need to implement other established media gateway control protocols.

Convergence server, or source MSC201may then take the new circuit ID information and use inter-MSC based messaging techniques to send routing information205(e.g. circuit ID information) for the device to target MSC134. Target MSC134then sends a handoff request206to the target RNC133which obtains an and information from the base station132(FIG. 1) regarding its capacity and availability. Assuming that base station132is ready to support mobile device101, target RNC133sends back an acknowledgement message207to target MSC134, indicating that the mobile core network is prepared to provide access to mobile device101. Target MSC134then relays this acknowledgement and any other routing information208(such as the availability information of base station132) that source MSC201may desire.

At this point the source MSC201sends a handoff command209to femtocell110, and femtocell110responds and notifies source MSC201that the handout has commenced210. The mobile core network then sets up dummy traffic channel211. Once dummy traffic channel211is established, then RNC133is able to send the handoff complete message212to target MSC134. Target MSC134will then send a final message to source MSC201to indicate that the target MSC is ready for the handoff213. In response, source MSC202sends an update message214to the media server124and informs media server124to bind the circuit ID that was provided initially. The circuit ID that was originally given by media server124is then bound and a message215reflecting such is conveyed to media server124from source MSC201. Once those two contacts happen the source MSC sends a clear command216to femtocell110which causes femtocell110to terminate its communication path with mobile device101.

As stated above, methods, such as the one shown above, which use a convergence server to work as an MSC in order to hand off active calls to a target MSC offer significant advantages over present femto/macrocell communication systems, including elimination of redundancy, simplification of mobile devices, and better performance with active mobile device calls. The convergence sever is able to function as an MSC as a result of the communication abilities shown herein (e.g. using SIP to send the commands down to the media gateway server, and to communicate with the femtocell). It is noted that other communication protocols may be used with the convergence server such as H248. However, at the present time SIP appears to be the simplest way to communicate between the convergence server and the media server.

FIG. 3shows a high level flow diagram300of a hand-in routine wherein a mobile device102is connected on an active call on a mobile core network, such as mobile core network130, and is attempting to transition to a packet switched network, such as packet switched network120. In this case, RNC133would initiate a handoff required message302to the MSC that is serving mobile device102, e.g. MSC134, which for this embodiment is the source MSC. Source MSC134sends to MSC301(which is now the target MSC), a directed message303containing routing information including information about mobile device102. Target MSC301in this embodiment may also be implemented by convergence server123. Target MSC301initiates a handoff request message304to the packet switched network's access point, shown as femtocell110. The handoff request is then acknowledged305by femtocell110.

Since femtocell110is a known device on the packet switched network, i.e. it is registered, handoff request message304will go through an packet switched network. But since the mobile device102is not registered in the packet switched network, when subsequent messages are sent over the packet switched network, mobile device102will not receive the messages. Thus, it is preferable to register mobile device102on the packet switched network. One method of registering mobile device102is implemented by the having the access point, such as femtocell110, send message305to register, via packet switched network120, mobile device102based on the information provided about the mobile device in handoff request304. Message305may be sent, for example, by using SIP or any other protocol compatible with the network devices. This registration method will result in having subsequent messages sent to mobile device102sent to femtocell110, which can then be relayed to mobile device102. Registration methods, such as the ones described herein are also set forth in concurrently filed application referenced above entitled “Security for Legacy Communication Devices when Operating on Packet Switched Networks.”

It is noted that there are other methods to register the mobile device. The example set forth above utilized femtocells which undertook the registration on behalf of the handset, even though the handset is not fully moved into the femtocell. Another exemplary method for registering the mobile device entails using the convergence server can finish the registration directly using the HSS interface, and the information coming into the IMS code.

At this point the circuit ID is known, and an invite is sent with that circuit ID information307to media server124. Media server124is notified that this circuit ID needs to be tied to a call to be routed to femtocell110, and media server124acknowledges such in response message308. Routing information309is then sent from target MSC301to source MSC134.

At this point, a handoff command312may be sent to RNC133and RNC133responds with a handoff commenced message310. Once the handoff commenced message311is sent, a dummy path312is established. Finally, the femtocell sends a handoff complete message313and that will trigger the target MSC301to send an update316to the previous circuit ID information307message that was previously sent to media server124to notify media server124that the call will be routed through target MSC304. And a response315is sent to the source MSC once the update314is complete. At this point an on channel signal316is sent to source MSC303, and source MSC303will send a clear command317to RNC133, which will release the traffic channel for mobile device300that just entered into femtocell307.

FIGS. 4A and 4Billustrate the movement of a data path401and control path402which occurs as a result of a handout of a femtocell to a mobile core, such as is illustrated inFIG. 2. InFIG. 4Amobile device403is in communication with femtocell access point404and PDG/PDIF405when mobile device403is communicating on a packet switched network. The data path401is routed through media server406and MGCF410, and then to a destination, such as PTSN407. The control path is sent through call session control function circuitry (CSCF)408, and then to the convergence server409. Convergence server409routes control path402back through CSCF408and then to MGCF410for. After the MGCF, data signal402is sent to PTSN407.

Embodiments are also configured to manipulate communication trunks. For example, as shown inFIGS. 4A and 4B, once mobile device403is handed off to the mobile core network411, data path401that is going through the femtocell412will be diverted to target MSC413. Data path401will also pass through base station414and connects with mobile device403. Control path402will also span between MSC413and convergence server409. It is also noted that signaling system protocols, such as signaling system number 7 (SS7), may control various aspects of the illustrated communications paths, such as the control path between MSC413and convergence server409.

Since convergence server409does not have a dedicated media server, embodiments of the present invention provide for a convergence server that is configured to manipulate media server406which is already in the path of the call. For example, embodiments of the present invention provide for a convergence server that is configured to utilize media server which is part of a VOIP, IMS network, etc., to have the traffic from the mobile core network directed towards the media server, and the media server can direct the flow of traffic to the target MSC. Sharing an existing media server to do the handoff and have the traffic diverted to the target MSC reduces the cost of the overall solution because the it allows the system to leverage existing media servers.

Likewise,FIGS. 5A and 5Bshow mobile device500which is being handed-in from macrocell501to femtocell502, such as is illustrated inFIG. 3. When mobile device502is communicating on macrocell501the data path503and control path504are both directed through BSS505and MSC506to their destination, such as PTSN507. When a handoff request is communicated, the control path504is diverted from MSC506to connect to convergence server509, which is also in communication with MGCF507and CSCF508. Embodiments of the present invention cause convergence server509to appear to MSC506as being another MSC, and in this case the target MSC. Convergence server509causes MSC506to divert the data path503to media server510and it is then routed through PDG511and femtocell access point512and then to mobile device500. Control path504is also routed through PDG511and femtocell access point512and then to mobile device500. As can be seen by this illustration, after the hand-in is complete, the communication path through the MSC506is still utilized and in the femtocell communication paths. Additionally, as with the example ofFIGS. 4A and 4B, signaling system protocols, such as SS7, may control various aspects of the illustrated communications paths, such as the control path between MSC506and convergence server509.