Apparatus and methods to facilitate seamless handoffs between wireless communication networks

Apparatus and methods for facilitating a handover of a wireless communication device on a first wireless communication network to a second wireless communication network, wherein the first and second wireless communication networks include communications protocols that are incompatible, are disclosed. The facilitation can include establishing communications between the wireless communication device and an interworking component of the second wireless communication network using a transparent tunnel through the first wireless communication network so that a message containing session information for the second wireless communication network can be exchanged. The facilitation further includes creating a profile on the second wireless communication network for a communication session between the wireless communication device and the second wireless communication network.

BACKGROUND

The present application relates generally to wireless communications, and more specifically to methods and systems to facilitate seamless handoffs between incompatible wireless communication networks.

Wireless communication systems are widely deployed to provide various types of communication content, such as voice, data, multimedia services, and so on. These systems may be multiple-access systems capable of supporting communication with multiple users by sharing the available system resources such as bandwidth and transmit power. Examples of such multiple-access systems include Code Division Multiple Access (CDMA) systems, Time Division Multiple Access (TDMA) systems, Frequency Division Multiple Access (FDMA) systems, 3GPP Long Term Evolution (LTE) systems, and Orthogonal Frequency Division Multiple Access (OFDMA) systems.

In recent years, users have also started to replace fixed line communications with mobile communications and have increasingly demanded great voice quality, reliable service, and low prices. The mobile communications are often implemented on mobile phone handsets or portable computers such as laptops or hand-held computers. As these devices have increased capabilities, users have desired to have access to data and multimedia services such as streaming video. As the demand for high-rate and multimedia data services rapidly grows, there lies a challenge to implement efficient and robust communication systems with enhanced performance to multiple users.

Although new network technologies are available that provides faster speeds, access networks implementing these technologies, referred to herein as “new access networks”, are not always available. When available, a wireless device will use the new access network. However, if the wireless device is moving between a new access network and a traditional access network not implementing these technologies, inter-technology handoff needs to occur. In cellular telecommunications, the term “handoff” refers to the process of transferring an ongoing call or data session from one channel connected to a network to another. “Seamless” handoff would refer to a session where there is little or no delay associated with the handoff. The term “handover” may also be used to refer to handoff. Preferably, no interruption in service should occur for the user while the transition is occurring. Just as importantly, implementing the handoff mechanism should not require the older access network to be updated.

SUMMARY

The following presents a simplified summary of one or more aspects in-order to provide a basic understanding of such aspects. This summary is not an extensive overview of all contemplated aspects of the disclosure, and is intended to neither identify key or critical elements of all aspects nor delineate the scope of any or all aspects. Its sole purpose is to present some concepts of one or more aspects in a simplified form as a prelude to the more detailed description that is presented later.

In accordance with one or more aspects and corresponding disclosure thereof, various aspects are described in connection with facilitating a handoff between networks. According to related aspects, a method performed by a wireless communication device to facilitate a handoff between networks is provided. The method can include establishing a first communication session with a first wireless communication network having a first communication protocol. The method can also include determining a desire to handoff to a second wireless communication network having a second communication protocol, wherein the second wireless communication network and the first wireless communication network are incompatible for communication. The method further includes obtaining an address of an interworking function corresponding to the second wireless communication network, wherein the interworking function is operable to establish a second communication session in the second wireless communication network. Further still, the method includes tunneling, via the first communication protocol, a data message through the first communication network to the interworking function based on the address of the interworking function, wherein the data message includes a payload including session transfer information in the second communication protocol for the second wireless communication network, the session transfer information for the second communication network being completely transparent to the first communication network. Yet further still, the method includes establishing a second communication session with the second wireless communication network in the second communication protocol, wherein the second communication session is based on the data message.

Another aspect relates to a wireless communications apparatus. The wireless communications apparatus can include at least one processor configured to facilitate a handoff between networks. The processor includes a first module for establishing a first communication session with a first wireless communication network having a first communication protocol; a second module for determining a desire to handoff to a second wireless communication network having a second communication protocol, wherein the second wireless communication network and the first wireless communication network are incompatible for communication; a third module for obtaining an address of an interworking function corresponding to the second wireless communication network, wherein the interworking function is operable to establish a second communication session in the second wireless communication network; a fourth module for tunneling, via the first communication protocol, a data message through the first communication network to the interworking function based on the address of the interworking function, wherein the data message includes a payload including session transfer information in the second communication protocol for the second wireless communication network, the session transfer information for the second communication network being completely transparent to the first communication network; and a fifth module for establishing a second communication session with the second wireless communication network in the second communication protocol, wherein the second communication session is based on the data message.

Yet another aspect relates to a wireless communications apparatus that facilitates a handoff between networks. The wireless communications apparatus can include means for establishing a first communication session with a first wireless communication network having a first communication protocol. The wireless communications apparatus can additionally include means for determining a desire to handoff to a second wireless communication network having a second communication protocol, wherein the second wireless communication network and the first wireless communication network are incompatible for communication. The wireless communications apparatus further includes means for obtaining an address of an interworking function corresponding to the second wireless communication network, wherein the interworking function is operable to establish a second communication session in the second wireless communication network. Further still, the wireless communications apparatus includes means for tunneling, via the first communication protocol, a data message through the first communication network to the interworking function based on the address of the interworking function, wherein the data message includes a payload including session transfer information in the second communication protocol for the second wireless communication network, the session transfer information for the second communication network being completely transparent to the first communication network; and also means for establishing a second communication session with the second wireless communication network in the second communication protocol, wherein the second communication session is based on the data message.

Still another aspect relates to a computer program product, which can have a computer-readable medium including code for causing at least one computer to establish a first communication session with a first wireless communication network having a first communication protocol. The computer-readable medium can also include code for causing the at least one computer to determine a desire to handoff to a second wireless communication network having a second communication protocol, wherein the second wireless communication network and the first wireless communication network are incompatible for communication. Moreover, the computer-readable medium can include code for causing the at least one computer to obtain an address of an interworking function corresponding to the second wireless communication network, wherein the interworking function is operable to establish a second communication session in the second wireless communication network. Further, the computer-readable medium can include a fourth set of codes for causing a computer to tunnel, via the first communication protocol, a data message through the first communication network to the interworking function based on the address of the interworking function, wherein the data message includes a payload including session transfer information in the second communication protocol for the second wireless communication network, the session transfer information for the second communication network being completely transparent to the first communication network. The computer-readable medium can include a fifth set of codes for causing a computer to establish a second communication session with the second wireless communication network in the second communication protocol, wherein the second communication session is based on the data message.

According to related aspects, a method performed by an interworking function to facilitate a handoff between networks is provided. The method can include receiving a tunneled message from a wireless communication device through a first wireless communication network using a first communication protocol, wherein the message includes a payload including session transfer information for the wireless communication device compliant with a second communication protocol for a second wireless communication network, wherein the second wireless communication network and the first wireless communication network are incompatible for communication. The method can also include establishing a session profile for the wireless communication device for a second communication session with the second wireless communication network in the second communication protocol, wherein the second communication session is based on the message.

Another aspect relates to an interworking function apparatus. The interworking function apparatus can include at least one processor configured to facilitate a handoff between networks. The processor is further configured to receive a tunneled message from a wireless communication device through a first wireless communication network using a first communication protocol, wherein the message includes a payload including session transfer information for the wireless communication device compliant with a second communication protocol for a second wireless communication network, wherein the second wireless communication network and the first wireless communication network are incompatible for communication. The processor is further configured to establish a session profile for the wireless communication device for a second communication session with the second wireless communication network in the second communication protocol, wherein the second communication session is based on the message.

Yet another aspect relates to an apparatus in an interworking function configured to facilitate a handoff between networks. The wireless communications apparatus can include means for receiving a tunneled message from a wireless communication device through a first wireless communication network using a first communication protocol, wherein the message includes a payload including session transfer information for the wireless communication device compliant with n a second communication protocol for a second wireless communication network, wherein the second wireless communication network and the first wireless communication network are incompatible for communication. The wireless communications apparatus can additionally include means for establishing a session profile for the wireless communication device for a second communication session with the second wireless communication network in the second communication protocol, wherein the second communication session is based on the message.

Still another aspect relates to a computer program product, which can have a computer-readable medium including code for causing at least one computer to receive a tunneled message from a wireless communication device through a first wireless communication network using a first communication protocol, wherein the message includes a payload including session transfer information for the wireless communication device compliant with a second communication protocol for a second wireless communication network, wherein the second wireless communication network and the first wireless communication network are incompatible for communication. The computer-readable medium can also include code for causing the at least one computer to establish a session profile for the wireless communication device for a second communication session with the second wireless communication network in the second communication protocol, wherein the second communication session is based on the message.

Still yet another aspect relates to an apparatus for facilitating a handoff between networks that is non-interoperable for communication there between. The apparatus includes a first establisher configured to establish communication with a first network that includes a first communication protocol; a determiner configured to determine an address of an interworking function for a second network. The second network using a second communication protocol that is non-interoperable with the first communication protocol. The apparatus further includes a second establisher configured to establish communication with the second network using the second communication protocol; and a tunneler configured to establish a tunnel through the first network using the first communication protocol, wherein the tunnel provides communication between the second establisher and the interworking function for the second network in the second communication protocol that is undetectable by the first network.

Still yet another aspect relates to an apparatus in an interworking function configured to facilitate a handoff between networks. The apparatus includes a receiving unit configured to receive a message from a wireless communication device in a first network. The first network using a first communication protocol and the message being tunneled through the first network using the first communication protocol. The apparatus also includes a communication profile establisher for establishing a communication profile, based on the receipt of the message from the wireless communication device, for the wireless communication device in a second network. The second network using a second communication protocol that is non-interoperable with the first communication protocol. The message includes content that provides information necessary for the establishment of the communication profile, the content being formatted in the second communication protocol.

To the accomplishment of the foregoing and related ends, the one or more aspects include the features hereinafter fully described and particularly pointed out in the claims. The following description and the annexed drawings set forth in detail certain illustrative aspects of the one or more aspects. These aspects are indicative, however, of but a few of the various ways in which the principles of various aspects may be employed and the described aspects are intended to include all such aspects and their equivalents.

DETAILED DESCRIPTION

The word “exemplary” is used herein to mean “serving as an example, instance, or illustration.” Any aspect described herein as “exemplary” is not necessarily to be construed as preferred or advantageous over other aspects. The disclosed aspects may be applied to any one or combinations of the following technologies: Code Division Multiple Access (CDMA) systems, Multiple-Carrier CDMA (MC-CDMA), Wideband CDMA (W-CDMA), High-Speed Packet Access (HSPA, HSPA+), Time Division Multiple Access (TDMA) systems, Frequency Division Multiple Access (FDMA) systems, Orthogonal Frequency Division Multiple Access (OFDMA) systems, or other multiple access techniques. A wireless communication system may be designed to implement one or more standards, such as Interim Standard 95 (IS-95), cdma2000, IS-856, W-CDMA, TD-SCDMA, and other standards.

For the purposes of facilitating the understanding of the various aspects of the disclosure, the following list of abbreviations will be used:

FIG. 1illustrates an exemplary wireless communication system100configured to support a number of users, in which various disclosed aspects may be implemented. As shown inFIG. 1, by way of example, the wireless communication system100provides communication for devices in multiple cells102, such as, for example, macro cells102a-102g, with each cell being serviced by a corresponding access point (AP), illustrated as APs104a-104gin the figure. Each cell may be further divided into one or more sectors. Various access terminals (ATs)106, illustrated as ATs106a-106k, also known interchangeably as user equipment (UE), are dispersed throughout the system. Each one of ATs106a-106kmay communicate with one or more APs104a-104gon a forward link (FL) and/or a reverse link (RL) at a given moment, depending upon whether the particular AT is active and whether it is in soft handoff, for example. The wireless communication system100may provide service over a large geographic region. For example, macro cells102a-102gmay cover a few city blocks in a neighborhood.

FIG. 2illustrates an exemplary CDMA communications system200. As shown inFIG. 2, a base station controller202can be used to provide an interface between a network204and all base stations dispersed throughout a geographic region. For ease of explanation, only one base station206is shown. The geographic region is generally subdivided into smaller regions known as cells. Again, for ease of explanation, only one cell210is shown. The base station206is configured to serve all subscriber stations208in its respective cell, which in this case is the cell210. In some high traffic applications, the cell210may be further divided into sectors, with a base station serving each sector. In the described aspect, three subscriber stations208a-208care shown in communication with the base station206. Each subscriber station208a-208cmay access the network204, or communicate with other subscriber stations208, through one or base stations206under control of the base station controller202.

FIG. 3illustrates a system300to facilitate a seamless handoff between two different types of networks configured in accordance to one aspect of the disclosure.

The system300includes a first access network, illustrated as access network (AN)1310, and a second access network, illustrated as access network AN2340, both to which an access terminal (AT)302is configured to connect. The AN1310and the AN2340utilizes a first and second wireless communications technologies, respectively. In one aspect, for example, the first and second wireless communication technologies are incompatible such that a handoff cannot be directly implemented by a respective one of the AN1310and the AN2340to the other one of the networks. The AN1310and the AN2340each includes base stations to connect to ATs. As illustrated, the AN1310includes a base station314and the AN2340includes a base station344. Each AN includes an AN session controlling component that stores session information between the network and each AT associated with the network. Thus, AN1310includes an AN1session controlling component312and AN2340includes an AN2session controlling component342.

The system300includes an Internet Protocol (IP) gateway320to which AN1310is connected and allows the ATs associated with AN1310to communicate data across a packet-switched internetwork using the Internet Protocol (IP). For example, the ATs associated with AN1310can communicate with devices or systems that are coupled to the packet-switched internetwork, which may include the “Internet” using IP. The internetwork can contain such servers that provide IP address lookup and name translation such as one or more Domain Name System (DNS) servers similar to a DNS server324. In one aspect, a security mechanism, such as a security gateway322, is used to control access from the IP gateway320. A query for the contact information for the security gateway322may be determined by using DNS server324. Further illustrated inFIG. 3is an Internetworking Function (IF) component330that provides services necessary for an AT such as the AT302to facilitate a handoff between the base station314of the AN1310and the base station344of the AN2340, as described further with reference toFIG. 4, where a seamless handoff facilitating process400is illustrated.

The IF component330is operable to receive handoff instructions and other messages from the AT302in a protocol suitable for AN2340, but received within one or more data packets formatted according to the protocol of AN1310so that these messages are carried as data packets. These data packets are ignored as commands, as far as AN1310is concerned. Thus, the message is actually formatted according to protocol of AN2340but is carried transparently on AN1310as “data.” Therefore, AN1310does not explicitly interpret or understand the message. To carry this message as data on AN1310, however, the AT302needs to transmit/receive messages using AN1310protocol (as it does with all other data packets). Therefore, the AT302is logically communicating with AN2340initially. Accordingly, IF component330is operable to establish an appropriate interface for the session controller and the BS of the second network based on the received messages. For example, the IF component330, when implemented for a HRPD to Ultra Mobile Broadband (UMB) application, will operate on what an AT sends to establish an appropriate interface for the UMB Session Reference Network Controller (SRNC) and the UMB Evolved Base Station (eBS) of the UMB network. In the UMB standard, the UMB SRNC includes an interface for communication with the UMB eBS. Further, the UMB eBS can communicate with other UMB eBS's. Thus, because the IF component330appears as another UMB eBS to the system, the IF component330can communicate with other components on the network such as the other UMB eBS's and the UMB SRNC. Specifically, the IF component330appears as an existing base station that can interface with other UMB eBS's and the UMB SRNC for the AT without having to modify the UMB network. In this approach, there is no change both to the HRPD-side and UMB-side for interworking. Further, the IF component330also can be applied in an LTE standard communication network, with the IF component330acting as the Mobility Management Entity (MME) to interface with a Serving Gateway (SGW) and evolved Node B (eNB) for a User Equipment (UE).

In contrast, a common approach for inter-network handoff of an AT between two networks is to utilize a control plane. In this approach, the AT sends a special message that requests handoff from an access network with one technology, referred to as access network A, to a target access network with another technology, and referred to as access network B. This special message is often a control message based on network A protocol. Network A subsequently use another interface to communicate this request with access network B so that access network B can return information to access network A that is then passed back to the AT. This information is needed by the AT to establish a session with network B before decoupling from network A. This requires that network B, the target network, has to include technology with a defined interface that is common between the two networks so that they understand how to communicate with each other. Furthermore, it requires changes in Network A to support modification on both its communication with the AT and a new interface to communicate with Network B. Thus, the technologies for the two networks need to be very tightly coupled, which is disadvantageous such that the technology of the existing infrastructure, such as network A, would have to be customized for interoperating with more than one network.

In contrast, in one aspect of the disclosure, seamless handoffs of ATs between access networks implementing different technologies may be facilitated without having to maintaining a coupling of the technologies. In other words, seamless handoff can be facilitated between different access networks so that no changes need to be made to existing infrastructures. Further, the different access networks would not need to support an interface with each other, which would allow the access networks to be “overlaid” on top of each other. For example, the access networks may implement wireless communication technology that uses different electromagnetic spectrums, and the ATs, which support these different spectrums, can switch (i.e., be handed off) from one network to another seamlessly without each AN being aware of inter-technology handoff.

Returning toFIG. 4, before the AT302can be handed off to the AN2340, a communication session profile in the AN2340needs to be established for the AT302in step412. The communication session profile is established by the AT302with the AN2340in a transparent fashion to the AN1310. In an aspect of the disclosure, as the communication session profile is created and stored in the AN2session controlling component342, the AT302needs to be able to communicate with the AN2. This is achieved by the AT302initially communicating with the IF330so as to then gain access to the AN2session controlling component342. Once the communication session profile has been established, handoff can occur as the AT302can communicate with the base station344.

In an aspect of the disclosure, the AT302establishes communicates with the IF330of the AN2340by tunneling messages through the AN1310using IP packets. In this fashion, AN1310does not need to be configured to communicate with AN2340.

The AT302first determines the IP address of the IF component330. The AT302may determine the IP address through a query to one of the DNS servers, such as the DNS server324, that are accessible from the IP gateway. The IP address that is returned to the AT302may be based on one or more criteria, including a physical location of the AT302with respect to the base station344, an ID stored on the AT302, and a context/session that the AT302desires to establish. The AT302provides an indicator of the geographic location of the AT, and during the look-up or contact process, the target network will allow the AT to contact the IF that is geographically closest to it.

The AT302initiates a process for seamless handoff, which includes creating a session profile in the AN2340. This includes contacting the AN2session controlling component342. In an aspect of the disclosure, the AT302sends a request and the information needed to establish the session profile to the IF component330, which then translates the information for the AN2session controlling component342.

In step414, once the session profile has been established for the AT302, the AT302will initiate the handoff and request that AN2340begin to assign dedicated resources such as radio resources and backhaul resources to the AT302. In an aspect of the disclosure, the handoff will require that the AN2340provide the AT302with a complete set of profile for the AN2340that is unbeknownst to the AN1310.

In step416, once the communications resources have been established for the AT302in the AN2340, the AT302will release its connection with the base station314of the AN1310and connect to the base station344of the AN2340. In an aspect of the disclosure, the AN2340may buffer data for the AT302during its transition from the AN1310and the AN2340that is needed to ensure a seamless handoff. Typically, the buffering is performed by a gateway device (not shown to simplify explanation). The gateway should buffer data for the AT instead of sending it to the IF because the IF is not a real BS, but only acts as one to establish the handoff.

FIG. 5illustrates a system500to facilitate a seamless handoff from an HRPD AN504to a UMB network, according to one aspect of the disclosure. InFIG. 5, solid lines indicate signaling and bearer, and dashed lines indicate only signaling. The HRPD AN504is coupled to a HRPD Packet Control Function (PCF)506, which is itself coupled to a Packet Data Serving Node (PDSN)508. An Interworking Security Function (ISF) component510is included for performing security services. For example, the ISF component510serves as a termination point for a secured tunnel between the AT502and the target UMB Radio Access Network (RAN) over the HRPD system.

The system500includes a control end point for the system500such as a UMB Session Reference Network Controller (SRNC)522. The control end point maintains a record of the association between each AT and a particular base station that is responsible for providing wireless communication support to that AT. The base station is referred to as a Forward Link Serving eBS (FLSE) for the AT.FIG. 5illustrates an UMB Evolved Base Station (eBS)524as an example of a base station. Each base station is required to register its association with a particular AT with the control end point of the system500, such as the UMB SRNC522, to ensure that a consistent record of which base station is handling that AT is maintained.

The system500includes a data end point for the system500such as a UMB access gateway (AGW)526. Data end points provides routing for each AT such that it directs data flow to the particular base station that is responsible for providing wireless communication support to that AT. Each base station is required to register its association with a particular AT with the data end point of the system500, such as the UMB AGW526, to ensure that proper data routing of the data directed to the particular AT is sent to the base station that is handling that AT is maintained. Once registered, the base station is referred to as the data attachment point (DAP) for the AT. The order of registration of a base station with a control end point and a data end point may change. In the example described below, the base station will first register with the data end point as a DAP before registering with the control end point as an FLSE.

The system500also includes a UMB Interworking Function (UIF) component (also referred to as an UMB eBS-lite component)520coupled to the ISF510. In one aspect, the UIF component520is a UMB eBS that does not have radio transceiver capability and serves as a UMB packet tunneling endpoint. The UIF component520communicates with the AT502using UMB packet tunneling over IP. The UIF component520allows pre-setup of UMB sessions before an AT makes an inter-technology handoff to the UMB network. In an aspect of the invention, the UIF component520should support all UMB Interoperability Specification (IOS) interfaces.

In an aspect of the disclosure, the UIF component520may be a standalone entity or may be collocated at a control point for the system500such as the UMB SRNC522. In the alternative, instead of being collocated at a control point, the UIF component520may be collocated at a base station such as the eBS524.

The operation of the system500will be described with reference to the call flow diagram shown inFIGS. 6-8, below. Described in detail therein is an aspect of the call flow that occurs when the AT502performs handoff from an HRPD network to a UMB network.

FIG. 6illustrates a call flow600that facilitates an initialization of a seamless handoff from the HRPD AN504to the UMB network in accordance to an aspect of the disclosure where, at point652, the AT502detects an existence of the UMB network by finding an advertised UMB pilot in an air interface overhead message from the HRPD AN504. The AT502can determine that it wants to switch networks based on either an implementation of an existing standard; for example, by the advertising presence of neighboring technologies, or a proprietary determination approach. For example, the AT502will always switch to a faster network if one is detected. The AT502obtains the AN ID of the advertised UMB eBS524.

At point654, the AT502obtains the Internet Protocol (IP) address of the UIF component520from a domain name system (DNS) server, using the same approach as described in the DNS lookup. The IP address will direct the AT502to a UIF component closest to the AT502. The AT502will then establish an IPsec tunnel to the UIF component520through the HRPD AN504. In aspects where the ISF component510is part of the system500, the AT502will need to determine the IP address of the ISF component510by performing a DNS query and establishing an IPsec tunnel with the ISF component510before the AT502contacts the UIF component520to establish the IPsec tunnel with the UIF component520. For the DNS query, the AT502shall form the Fully Qualified Domain Name (FQDN) for the ISF component510as follows:<UMB-ANID>.UMB.ISF.<domain-name>

and the FQDN for the UIF component520would be in format of:<UMB-ANID>.UMB.RAN.<domain-name>

where:<domain-name> is discovered via Dynamic Host Configuration Protocol (DHCP), and<UMB-ANID> is the hex representation in ASCII of the HRBD subnet provided to the AT502via the HRPD air-interface or UMB air-interface.

The security policy of the network500may allow for the setup of an IP tunnel between the AT502and a target RAN without establishing an IPsec tunnel through the ISF component510. In this case, the IP address of the ISF component510may be configured to be returned as all zeros to indicate to the AT502that the establishment of an IPsec tunnel to the ISF component510is not required before an IPsec tunnel is established with the UIF component520.

At point656, the AT performs a UMB session establishment with the UIF component520and the UMB SRNC522if the UMB session does not exist or cannot be retrieved by the UIF component520. Otherwise, the UIF component520retrieves the UMB session from the UMB SRNC522. In either case, the UIF component520will initially become the FLSE for the AT502.

At point658, the UIF component520assigns a LinkID for the AT502so that the AT502can start IP services on the UMB RAN. Specifically, the LinkID assignment process provides the AT502with the information necessary to connect with the UBM RAN.

At point660, upon assignment of the LinkID, if the AT502is configured to use AT-assisted DAP handoff, the AT502sends a DAPMoveRequest message to the UIF component520to trigger an initial Proxy Mobile IP (PMIP) tunnel setup between the UIF component520and the UMB AGW526. In other words, the AT will trigger a handoff of the DAP registration with the access gateway of the UMB RAN by sending this request; such that the UIF component520informs the UMB AGW526that it is the DAP for the AT502. If AT-assisted DAP handoff is not configured for the AT502, the UIF component520will still autonomously continue with the following step.

At point662, the UIF component520sends a PMIP-Registration Request message to the UMB AGW526to initiate the PMIP tunnel setup, with a signaling-only binding-type extension being indicated. The UIF component520wwill also start a timer Trrq-pmipas a timeout counter.

At point664, the UMB AGW526sends a PMIP Registration Reply message to complete PMIP tunnel setup with the UIF component520to confirm that the UIF component520is now the DAP for the AT502. The timer Trrq-pmipis now stopped.

At point666, the UIF component520sends a DAPAssignment message to the AT502that indicates to the AT502that the UIF component520is now the DAP for the AT502.

At point668, the UIF component520sends an IPT-Notification message to the UMB SRNC522to indicate it is the current DAP for the AT502and starts a timer Tnot-ipt.as a timeout counter for this registration.

At point670, the UMB SRNC522responds with an IPT-Notification Ack message to acknowledge that the UIF component520is the FLSE for the AT502. Upon receipt of the message, the UIF component520stops timer Tnot-ipt.

At point672, upon assignment of the DAP, the AT502presents an IP interface to the application and may request an IP address from the UMB AGW526at any time.

FIG. 7illustrates a call flow700to facilitate a connection release by the AT502from the HRPD AN504in accordance with one aspect of the disclosure where, starting at point752, either the AT502or the HRPD AN504determines it is preferable to initiate the handoff.

At point754, where the handoff is determined to be desirable, the AT502sends a RouteOpenRequest message to the UMB eBS524, via the previously established tunnel to the UIF component520. In an aspect of the disclosure, the UMB eBS524will receive the communication from the UIF component520through a backhaul communication network (not shown). The backhaul communication network is normally used by the various base stations to communicate with each other. The UMB eBS524will be unaware that the request sent by the AT502to the UIF component520was not initiated over a radio link.

At point756, once the UMB eBS524receives the request from the AT to establish a session, the UMB eBS524sends an IAS-Session Information Request message to the UMB SRNC522to request a copy of the session information for the session between the UIF component520and the AT502. The UMB eBS524will use this information to establish ultimately a session with the AT520. The UMB eBS524will also start a timer Tsir-iasas a timeout counter for the session information request.

At point758, the UMB SRNC522sends an IAS-Session Information Response message to the UMB eBS524that will provide the base station with the session information and the AN ID of the DAP, which is the UIF component520. Upon receipt of the message, the UMB eBS524stops timer Tsir-ias.

At point760, the UMB eBS524sends a RouteOpenAccept message to the AT502to complete route establishment with the AT502.

At point762, the UMB eBS524completes a security establishment procedure such as a key exchange procedure with the AT502. In one aspect of the disclosure, this can occur in parallel with point760, where the UMB eBS524sent the RouteOpenAccept message to the AT502to complete route establishment with the AT502.

At point764, the AT502updates its own route map, which includes a list of base stations with which it may communicate, with information about the UIF component520, the UMB SRNC522and the UMB eBS524.

At point766, the AT502sends a mobile IP (MIP) registration request message to the UMB AGW526. As further described herein, the MIP registration request will allow the AT to transition from the IP address it has on the HRPD RAN504to a different IP address on the UMB RAN, but without loss of data.

At point768, the UMB AGW526forwards the MIP Registration Request message to a home agent614of the AT502. In one aspect, the home agent614maintains a public IP address for the AT502so that even if the AT502switches between different networks and is assigned different IP addresses by each of the different networks, the AT502may still be reached by its public IP address. The home agent614will be updated with the new IP address of the AT502with the AGW526by the MIP Registration Request.

At point770, the home agent updates the AT502's binding record and sends an MIP Registration Reply message to the UMB AGW526, which then holds the message until a data path to send information to the AT502is reestablished.

At point772, upon the assignment of the new DAP and a new Link ID, the AT502can release its connection with the HRPD AN504. In one aspect, this point may occur any time after point770.

FIG. 8illustrates a call flow process802to facilitate a session establishment by the AT502with the UMB RAN in accordance with one aspect of the disclosure.

At point852, the AT502tunes its radio to the UMB RAN. Specifically, continuing with the example given herein, the AT502tunes its radio to the UMB eBSI524.

At point854, the AT502selects the UMB eBS524as its new FLSE, which will cause the UMB eBS524to initiate contact with the control end point, the UMB SRNC522, to inform it that the base station is now responsible for communication with the AT502, as described below.

At point858, the UMB eBS524sends an IPT-Notification message to the UIF component520to inform the UIF component520that the UMB eBS524is now handling communication with the AT502and starts timer Tnot-ipt. The message contains the AN ID of the UMB eBS524. Upon receipt of the IPT-Notification message, the UIF520sends back an IPT-Notification ACK message to the UMB eBS524. Upon receipt of this acknowledgement, the UMB eBS524stops timer Tnot-ipt.

At point860, the UMB eBS524updates the PMIP binding with the UMB AGW526by sending a PMIP-Registration Request message to the UMB AGW526and starts timer Trrq-pmip. This step may occur any time after point756ofFIG. 7, where the UMB eBS524sent an IAS-Session Information Request message to the UMB SRNC522to request a copy of the session and started timer Tsir-ias.

At point862, the UMB AGW526confirms the binding update by sending back a PMIP-Registration Reply message to the UMB eBS524. Upon receipt of the reply, the UMB eBS524stops timer Trrq-pmip. After this point, the UMB eBS524becomes the new DAP and data flows to and from the AT502resumes.

At point864, the UMB AGW526sends the buffered MIP Registration Reply to the DAP, which is the UMB eBS524. The UMB eBS524then forwards MIP Registration Reply to the AT502.

At point866, the UMB eBS524sends IPT-Notification message to the UMB SRNC522with the indication it is the new DAP and starts timer Tnot-ipt. Upon receipt of the IPT-Notification message, the UMB SRNC522sends back an IPT-Notification Ack message to the UMB eBS524. Upon receipt of this acknowledgement, the UMB eBS524stops timer Tnot-ipt.

At point868, the UMB eBS524sends an IPT-Notification message to the UIF520to indicate it is the new DAP and starts timer Tnot-ipt. Upon receipt of the IPT-Notification message, the UIF component520sends back an IPT-Notification Ack message to the UMB eBS524and the AT502will now communicate with UMB eBS524. Upon receipt of this acknowledgement, the UMB eBS524stops timer Tnot-ipt. In aspect of the disclosure, the various operations in points866and868may occur in parallel.

FIG. 9is an illustration of a mobile device900that facilitates handoff between networks that do not inter-operate with the same wireless communication protocol. In some cases, the networks can have completely incompatible communication protocols.

The mobile device900includes a receiver902that receives a signal from, for instance, a receive antenna (not shown), performs typical actions on (e.g., filters, amplifies, downconverts, etc.) the received signal, and digitizes the conditioned signal to obtain samples. Receiver902can include a demodulator904that can demodulate received symbols and provide them to a processor906for channel estimation. Processor906can be a processor dedicated to analyzing information received by receiver902and/or generating information for transmission by a transmitter920, a processor that controls one or more components of the mobile device900, and/or a processor that both analyzes information received by receiver902, generates information for transmission by transmitter920, and controls one or more components of the mobile device900.

The mobile device900can additionally include memory908that is operatively coupled to processor906and that can store data to be transmitted, received data, information related to available channels, data associated with analyzed signal and/or interference strength, information related to an assigned channel, power, rate, or the like, and any other suitable information for estimating a channel and communicating via the channel. Memory908can additionally store protocols and/or algorithms associated with estimating and/or utilizing a channel (e.g., performance based, capacity based, etc.).

The mobile device900can further include a first network establisher910that can establish a first communication session with a first wireless communication network having a first communication protocol, a determiner912that can determine a desire to handoff to a second wireless communication network having a second communication protocol, wherein the second wireless communication network and the first wireless communication network are incompatible for communication. The mobile device also includes an address acquirer914to obtain an address of an interworking function corresponding to the second wireless communication network, wherein the interworking function is operable to establish a second communication session in the second wireless communication network, a tunneler916that tunnels, via the first communication protocol, a message through the first communication network to the interworking function based on the address, wherein the message includes a payload including session transfer information in the second communication protocol; and, a second network establisher918that establishes a second communication session with the second wireless communication network in the second communication protocol, wherein the second communication session is based on the message.

FIG. 10is used to describe aspects of a HRPD to UMB handoff where there is a usage of a Link-Layer Tunneling (LLT) interface for UMB packet tunneling over IP. In an aspect of the disclosure, pre-setup of a UMB session while an AT is on an HRPD AN can be accomplished transparently to the HRPD network to an existing UMB eBS by allowing the AT to support the LLT interface. The LLT interface is used for tunneling the UMB route protocol packets over the HRPD network. The communication between the AT and the UMB eBS to pre-setup a UMB session and perform authentication before the AT is handed off to the UMB is completely transparent the HRPD network. InFIG. 10a transport protocol is shown when an AT1010uses the LLT interface to establish a route for an UMB eBS1050. When communicating over the LLT interface1024, the AT1010shall set the destination IP address to the IP address of the UMB eBS1050. The UMB eBS1050shall set the destination IP address to the IP address that it has received over the LLT tunnel on the LLT interface1064if no IPT-Notification message is received indicating that the sender is the FLSE. The communication between IP stack1026and IP stack1066occurs completely over the IP network1002that, before the transition from the HRPD AN to the UMB RAN, is performed completely over the PHY and MAC protocols of the HRPD. Thus, although not show, the output of IP stack1026is fed into a stack for the HRPD system.

While the specification describes particular examples of the present invention, those of ordinary skill can devise variations of the present invention without departing from the inventive concept. For example, the teachings herein refer to circuit-switched network elements but are equally applicable to packet-switched domain network elements.

FIG. 11illustrates a system1100of a wireless communication device for facilitating a handoff between networks. As depicted, the system1100includes functional blocks that can represent functions implemented by a processor, software, or combination thereof (e.g., firmware). The system1100includes a logical grouping1102of electrical components that facilitate handing off between networks. Logical grouping1102can include means for establishing a first communication session with a first wireless communication network having a first communication protocol1104. In this regard, the wireless communication device can communicate with the first wireless communication network as described herein. Moreover, logical grouping1102can include means for determining a desire to handoff to a second wireless communication network having a second communication protocol, wherein the second wireless communication network and the first wireless communication network are incompatible for communication1106. Thus, the wireless communication device can communicate with the second wireless communication network even though the first and second wireless communication networks cannot communicate with each other. Furthermore, logical grouping1102can include means for obtaining an address of an interworking function corresponding to the second wireless communication network, wherein the interworking function is operable to establish a second communication session in the second wireless communication network1108. In this regard, the wireless communication device can initiate communication with an internetworking device that is configured to establish, in the second wireless communication network, a second communication session. Additionally, the system1100can include a memory1114that retains instructions for executing functions associated with electrical components1104,1106,1108,1110and1112. While shown as being external to memory1114, it is to be understood that electrical components1104,1106,1108,1110and1112can exist within memory1110.

FIG. 12illustrates a system1200of an internetwork function for facilitating a handoff between networks. As depicted, the system1200includes functional blocks that can represent functions implemented by a processor, software, or combination thereof (e.g., firmware). The system1200includes a logical grouping1202of electrical components that facilitate handing off between networks. Logical grouping1202can include means for receiving a tunneled message from a wireless communication device through a first wireless communication network using a first communication protocol, wherein the message includes a payload including session transfer information for the wireless communication network in a second communication protocol for a second wireless communication network, wherein the second wireless communication network and the first wireless communication network are incompatible for communication1204. In this regard, the interworking function can communicate with the wireless communication device to receive messages for the second wireless communication network as described herein. Moreover, logical grouping1202can include means for establishing a session profile for the wireless communication device for a second communication session with the second wireless communication network in the second communication protocol, wherein the second communication session is based on the message1206. Thus, the wireless communication device can establish a communication session to communicate with the second wireless communication network via the interworking function even though the first and second wireless communication networks cannot communicate with each other. Additionally, the system1200can include a memory1214that retains instructions for executing functions associated with electrical components1204, and1206. While shown as being external to memory1214, it is to be understood that electrical components1204, and1206can exist within memory1210.