Abstract:
Apparatus for bi-directional handover are disclosed. An apparatus configured to perform handover from a wireless code division multiple access (WCDMA) to a wireless broadband (WiBro) network is disclosed. An apparatus configured to perform handover from a WCDMA network to a WiFi (IEEE 802.11x) network is disclosed. An apparatus configured to perform handover from a WiFi network to a WCDMA network is disclosed.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit of U.S. provisional application No. 60/971,950 filed on Sep. 13, 2007 and 60/972,095 filed on Sep. 13, 2007, which are incorporated by reference as if fully set forth. 
    
    
     TECHNICAL FIELD 
     The subject matter disclosed herein relates to wireless communications. 
     BACKGROUND 
     The IEEE 802.21 Media Independent Handover (MIH) standard defines mechanisms and procedures that aid in the execution and management of inter-access technology mobility management. IEEE 802.21 defines three main services available to Mobility Management applications. Referring to  FIG. 1 , these services are the Event Service  100 , the Information Service  105  and the Command Service  110 . These services aid in the management of handover operations, system discovery and system selection by providing information and triggers from lower layers  115  to upper layers  120 , and lower layer commands from upper layers  120  to lower layers  115  via a media independent handover function (MIHF)  125 . While  FIG. 1  shows MIHF  125  as a middle layer in a protocol stack, MIHF  125  may also be implemented as an MIH plane that is capable of exchanging information and triggers directly with each and every layer of a technology-specific protocol stack. 
     Events may indicate changes in state and transmission behavior of the physical, data link and logical link layers, or predict state changes of these layers. The Event Service  100  may also be used to indicate management actions or command status on the part of the network or a management entity. The command service  110  enables higher layers to control the physical, data link, and logical link layers (referred to collectively as lower layers). The higher layers may control the reconfiguration or selection of an appropriate link through a set of handover commands. If an MIHF supports the command service, all MIH commands are mandatory in nature. When an MIHF receives a command, it is always expected to execute the command. The Information Service  105  provides a framework and corresponding mechanisms by which an MIHF entity may discover and obtain network information existing within a geographical area to facilitate handover. 
     The MIH standard may be applied to support handover between various radio access technologies (RATs), including wireless code division multiple access (WCDMA), IEEE 802.11x (WiFi), IEEE 802.3, IEEE 802.14, IEEE 802.16 (WiMAX), IEEE 802.16e (WiBro), Third Generation Partnership Project (3GPP) and Third Generation Partnership Project Two (3GPP2) technologies. A wireless transmit/receive unit (WTRU) may be handed over from a network of one type to another. Where a WTRU can communicate via WCDMA and WiBro technologies, it would be beneficial for the WTRU to support MIH handover from WCDMA to WiBro and from WiBro to WCDMA. Where a WTRU can communicate via WCDMA and WiFi technologies, it would be beneficial for the WTRU to support MIH handover from WCDMA to WiFi and from WiFi to WCDMA. An approach is required for a WTRU to support MIH bi-directional handover in these and other contexts. Therefore, it would be beneficial for MIH handover to be supported in a WTRU via an MIH middleware. 
     SUMMARY 
     Apparatus for bi-directional handover are disclosed. An apparatus configured to perform handover from a wireless code division multiple access (WCDMA) to a wireless broadband (WiBro) network is disclosed. An apparatus configured to perform handover from a WCDMA network to a WiFi (IEEE 802.11x) network is disclosed. An apparatus configured to perform handover from a WiFi network to a WCDMA network is disclosed. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       A more detailed understanding may be had from the following description of a preferred embodiment, given by way of example and to be understood in conjunction with the accompanying drawings wherein: 
         FIG. 1  is an IEEE 802.21 protocol architecture; 
         FIG. 2  is a block diagram of an exemplary WTRU; 
         FIG. 3  is a block diagram of an exemplary PC; 
         FIG. 4  is a functional block diagram of an exemplary registration procedure for WCDMA to WiBro handover; 
         FIG. 5  is a functional block diagram of an exemplary registration procedure for WCDMA to WiBro handover; 
         FIG. 6  is a functional block diagram of an exemplary detection procedure for WCDMA to WiBro handover; 
         FIG. 7  is a functional block diagram of an exemplary detection procedure for WCDMA to WiBro handover; 
         FIG. 8  is a functional block diagram of an exemplary detection procedure for WCDMA to WiBro handover; 
         FIG. 9  is a functional block diagram of an exemplary handover trigger and execution start procedure for WCDMA to WiBro handover; 
         FIG. 10  is a functional block diagram of an exemplary handover trigger and execution finish procedure for WCDMA to WiBro handover; 
         FIG. 11  is a functional block diagram of an exemplary registration procedure for WiFi to WCDMA handover; 
         FIG. 12  is a functional block diagram of an exemplary detection procedure for WiFi to WCDMA handover; 
         FIG. 13  is a functional block diagram of an exemplary handover and execution start procedure for WiFi to WCDMA handover; 
         FIG. 14  shows a functional block diagram of an exemplary handover finish execution procedure for WiFi to WCDMA handover; 
         FIG. 15  is a functional block diagram of an exemplary registration procedure for WCDMA to WiFi handover; 
         FIG. 16  is a functional block diagram of an exemplary alternative registration procedure for WCDMA to WiFi handover; 
         FIG. 17  is a functional block diagram of an exemplary detection procedure for WCDMA to WiFi handover; 
         FIG. 18  is a functional block diagram of an exemplary alternative detection procedure for WCDMA to WiFi handover; 
         FIG. 19  is a functional block diagram of an exemplary alternative detection procedure for WCDMA to WiFi handover; 
         FIG. 20  is a functional block diagram of an exemplary handover trigger and execution start procedure for WCDMA to WiFi handover; and 
         FIG. 21  is a functional block diagram of an exemplary finish handover execution procedure for WCDMA to WiFi handover. 
     
    
    
     DETAILED DESCRIPTION 
     When referred to herein, the terminology “wireless transmit/receive unit (WTRU)” includes but is not limited to a user equipment (UE), a mobile station, a fixed or mobile subscriber unit, a pager, a cellular telephone, a personal digital assistant (PDA), a computer, or any other type of user device capable of operating in a wireless environment. When referred to herein, the terminology “base station” includes but is not limited to a Node-B, a site controller, an access point (AP), or any other type of interfacing device capable of operating in a wireless environment. 
       FIG. 2  is a WTRU  200  in accordance with an embodiment. The WTRU includes a transceiver  201 , receiver  202 , and antenna  203 . In communication with the transceiver  201  and receiver  202  are an 802.11x modem  210 , 802.16/WiBro modem  220 , and a WCDMA modem  230 . In communication with the modems  210 ,  220 ,  230  is a processor  204  that includes an MIH middleware  250 . In accordance with different embodiments, a WTRU need not include modems of all three types depicted in  FIG. 2 . A WTRU in accordance with an embodiment may include a pair of modems such as an 802.11x modem and a WCDMA modem. A WTRU in accordance with another embodiment may include a pair of modems such as an 802.16/WiBro modem and a WCDMA modem. 
       FIG. 3  depicts a PC  300  for wireless communication in accordance with an embodiment. The PC  300  includes a network connection manager  301  that provides a graphical user interface (GUI) to a user. The network connection manager  301  communicates with an MIH middleware  350  via MIH APIs  312 . The middleware  350  is in communication with a Mobile Internet Protocol (MIP) client  302  via MIH APIs  311 . The MIH middleware  350  communicates with the network protocol modules  310  of the PC operating system via operating system socket APIs  309 . Protocols that may be implemented by the network protocol modules  310  include User Datagram Protocol (UDP), Transmission Control Protocol (TCP), and Internet Protocol (IP). The MIP client  302  also communicates with the network protocol modules  309  via operating system socket APIs  309 . The MIH middleware communicates via MIH APIs  313  with multiple RAT device drivers, including a WiFi driver  303  and a WiBro driver  304 . The WiFi driver  303  is in communication with a WiFi stack  306 , and the WiBro driver  304  is in communication with a WiBro stack  307 . The WiFi stack  306  may be integrated into a technology such as a Mini Peripheral Component Interconnect (PCI) WiFi card  308 . The middleware  350  may also communicate with a WCDMA stack  305  via communication technologies such as Universal Serial Bus (USB), serial ports, or virtual serial ports implemented over USB. When the middleware  350  communicates with the WCDMA stack  305  via a serial port or virtual serial port technology, it may do so over a dedicated communications port using AT commands compliant with the Third Generation Partnership Project (3GPP). In an embodiment, the WCDMA stack  305  may be integrated into a USB device  314  such as a USB dongle. Communication between the WiBro device driver  304  and the WiBro stack  307  may be accomplished via a communication technology such as USB. The MIH middleware  350  may communicate with other functions, drivers and RATs using MIH applications, and other operating system application such as Microsoft Windows applications. When the PC operating system is Microsoft Windows, WiFi is supported in the operating system through the use of ObjectID (OID). In an embodiment, OIDs can be mapped to MIH primitives; in such a case, the MIH middleware  350  may process the OIDs for link detection, handover detection, and the like. 
     Approaches for supporting handover in MIH across WiBro to WCDMA and vice versa may include handovers triggered by a media independent handover (MIH) server and not by WCDMA radio access, detecting WiBro when a WTRU is in a WCDMA network, and policies to perform a bi-directional handover. Technologies and approaches such as Mobile internet protocol (IP), break before make, and the like, may also be utilized. 
     In order to facilitate bi-directional handover between WiBro and WCDMA technologies, the MIH server side may include a method to detect WiBro when in WCDMA. This may be accomplished by providing a WTRU with a WiBro neighbor list when the WTRU is in WCDMA coverage. A database may be utilized in the MIH server that correlates the topologies of WCDMA and WiBro cells. Alternatively, a periodic scan command may be communicated to the WTRU to search for WiBro neighbors. The MIH server may include policies to trigger handovers. Additionally, aspects of middleware to support MIH messaging and relating processing may include getting a WiBro neighbor list, periodic scan commands for WiBro, an MIH controlled handover back to WiBro, and the like. 
       FIG. 4  is a functional block diagram of an exemplary registration procedure for WCDMA to WiBro handover in accordance with an embodiment. The WTRU  200  includes an MIH middleware  250 , WCMDA modem  230 , and a WIBRO modem  220 . The WCDMA modem  230  communicates with an IP stack  465 . The IP stack  465  communicates via IP with a Domain Name Server (DNS)  470 , a Foreign Agent server (FA)  475 , and an MIH server  480 . The IP stack  465  can be configured to use User Datagram Protocol (UDP) or Transmission Control Protocol (TCP) in the transport layer. 
     The registration procedure is started in the WCDMA network. At  401 , a Packet Data Protocol (PDP) context is activated and IP connectivity is setup. At  402 , middleware interactions are started. At  403 , the MIH middleware  250  acts to start MIH discovery. At  404 , the WCDMA modem  230  performs MIH server discovery in conjunction with the DNS  470 . At  405 , the MIH middleware  250  acts to obtain an Home Agent (HA) IP address. A Home Agent Address Query message  406  is communicated to the WCDMA modem  230 . At  407 , the WCDMA modem  230  communicates a query for a Mobile IP HA address to the FA server  475  via the IP stack  465 . At  408 , the MIH middleware  250  acts to start an MIH session. The MIH session may include capability, discovery, registration, event subscription, and link configure functions. At  409 , the WCDMA modem  230  communicates a start MIH session message to the MIH server  480  via the IP stack  465 . 
     At the conclusion of the procedure depicted in  FIG. 4 , State One  410  is achieved. 
       FIG. 5  is a functional block diagram of an exemplary registration procedure for WCDMA to WiBro handover in accordance with another embodiment. The WTRU  200  includes the MIH middleware  250 , WCMDA modem  230 , and WIBRO modem  220 . The WCDMA modem  230  communicates with the IP stack  465 . The IP stack  465  communicates via IP with the MIH server  480 . The IP stack  465  can be configured to use UDP or TCP in the transport layer. As shown in  FIG. 5 , the registration procedure is performed after handover to WCDMA. 
     At  501 , successful handover to WCDMA is completed and an IP connection is established. At  502 , middleware interactions are started. At  503 , the MIH middleware  250  acts to register with the MIH server  480 . At  504 , the WCDMA modem  230  re-registers with the MIH server  408  via the IP stack  465 . At  505 , the MIH middleware  250  continues the MIH session. The MIH session includes event subscription and link configuration functions. At  506 , the WCDMA modem  230  communicates the continuation of the MIH session to the MIH server  480  via the IP stack  465 . 
     At the conclusion of the procedure depicted in  FIG. 5 , State One  410  is achieved. 
       FIG. 6  is a functional block diagram of an exemplary detection procedure for WCDMA to WiBro handover in accordance with an embodiment. The WTRU  200  includes the MIH middleware  250 , WCMDA modem  230 , and WIBRO modem  220 . The WCDMA modem  230  communicates with the IP stack  465 . The IP stack  465  communicates via IP with the MIH server  480 . The IP stack  465  can be configured to use UDP or TCP in the transport layer. The procedure of  FIG. 6  may be begun when State One  410  has been achieved. 
     As seen in  601 , a WCDMA session is ongoing. As seen in  602 , in the procedure of  FIG. 6 , WiBro cell availability may be detected through proprietary system information (SI). At  603 , the WCDMA modem  230  predicts availability of WiBro coverage and reports the prediction in a WiBro Available (Link Detected Indication) message  604 . At  605 , the MIH middleware  250  acts to inform the MIH server  480  about the availability of WiBro cells. The availability of WiBro cells is communicated at  606  by the WCDMA modem  230  via IP stack  465 . At  605 , if the WTRU moves back to a WCDMA cell where there is no WiBro coverage, a ROLLBACK_INDICATION message may be sent to the MIH server  480 . 
     At  607 , the MIH server  480  has sent a list of WiBro cells and reporting thresholds via the IP stack  465  of the WCDMA modem  230 . At  608 , the MIH middleware  250  acts to start the WiBro stack for potential handover and to request a scan report. Performance of  608  includes sending a LINK_ACTION_REQUEST message  609  to the WiBro modem  220 . At  610 , the WiBro modem  220  turns on in receiver (Rx) mode and starts scanning. The WiBro modem  220  then sends a LINK_ACTION_CONFIRM message  611  to the MIH middleware  250 . 
     At  612 , the WCDMA modem  230  sends a WCDMA measurement report  613  to the MIH middleware  250 . At  614 , the WiBro modem  220  periodically provides a WiBro measurement report  615  to the MIH middleware  250  after WiBro scan results indicate that internal thresholds are crossed. 
     At the conclusion of the procedure depicted in  FIG. 6 , State Two  690  is achieved. 
       FIG. 7  is a functional block diagram of an exemplary detection procedure for WCDMA to WiBro handover in accordance with another embodiment. The WTRU  200  includes the MIH middleware  250 , WCMDA modem  230 , and WIBRO modem  220 . The WCDMA modem  230  communicates with the IP stack  465 . The IP stack  465  communicates via IP with the MIH server  480 . The IP stack  465  can be configured to use UDP or TCP in the transport layer. As seen in  701 , a WCDMA session is ongoing. As seen in  702 , in the procedure of  FIG. 7 , periodic registration with the MIH server allows the MIH server to know the universal mobile telecommunications system (UMTS) cell ID. The procedure of  FIG. 7  may be begun when State One  410  has been achieved. 
     At  703 , the MIH server  480  sends a scan request that includes a request for the list of WiBro cells and a threshold for reporting. This may be in the form of an MIH_SCAN_REQUEST message  704 . At  705 , the MIH middleware  250  acts to start the Wibro stack of potential handover and to request a scan report. The MIH middleware  250  may perform  705  by sending a LINK_ACTION_REQUEST message  706  to the WiBro modem  220 . At  707 , the WiBro modem  220  turns on in receiver (Rx) mode and starts scanning. The WiBro modem then sends a LINK_ACTION_CONFIRM message  708  to the MIH middleware  250 . 
     At  711 , the WiBro modem  220  reports periodically the requested WiBro scan result after internal thresholds are crossed. This WiBro modem reporting may be in the form of a WiBro measurement report  712  to the MIH middleware  250 . At  709 , the WCDMA modem  230  sends WCDMA measurement reports in a WCDMA measurement report message  710  to the MIH middleware  250 . 
     At the conclusion of the procedure depicted in  FIG. 7 , State Two  690  is achieved. 
       FIG. 8  is a functional block diagram of an exemplary detection procedure for WCDMA to WiBro handover in accordance with another embodiment. The WTRU  200  includes the MIH middleware  250 , WCMDA modem  230 , and WIBRO modem  220 . The procedure of  FIG. 8  may be begun when State One  410  has been achieved. 
     As depicted in  801 , a WCDMA session is ongoing. At  802 , the MIH middleware  250  acts to start the WiBro modem  220  for continuous scanning and to request a scan report. This may be in the form of a LINK_ACTION_REQUEST message  803  communicated to the WiBro modem  220 . At  804 , the WiBro modem  220  turns on in receiver (Rx) mode and starts continuous scanning. The WiBro modem  220  may send a LINK_ACTION_CONFIRM message  805  to the MIH middleware  250 . 
     At  809 , the WCDMA modem  230  sends WCDMA measurement reports in a WCDMA measurement report message  806  to the MIH middleware  250 . At  807 , the WiBro modem  220  reports periodically the requested WiBro scan result after internal thresholds are crossed. This WiBro modem reporting may be in the form of a WiBro measurement report  808  sent to the MIH middleware  250 . 
     At the conclusion of the procedure depicted in  FIG. 8 , State Two  690  is achieved. 
       FIG. 9  is a functional block diagram of a handover trigger and execution start procedure for WCDMA to WiBro handover in accordance with an embodiment. The WTRU  200  includes the MIH middleware  250 , WCMDA modem  230 , and WIBRO modem  220 . The WCDMA modem  230  communicates with the IP stack  465 . The IP stack  465  communicates via IP with the MIH server  480 . The IP stack  465  can be configured to use UDP or TCP in the transport layer. The procedure of  FIG. 9  may be begun when State Two  690  has been achieved. 
     At  901 , the MIH middleware  250  acts to send a measurement report  902  to the MIH server  480 . The measurement report  902  is sent to the MIH server  480  when thresholds set by the MIH server  480  through an MIH_LINK_CONFIGURE_THRESHOLDS command have been crossed. The measurement report  902  is sent from the MIH middleware  250  to the WCDMA modem  230 , and is then sent by the WCDMA modem  230  via the IP stack  465  to the MIH server  480 . 
     At  903 , the WCDMA modem  230  receives a handover command from the MIH server  480 . The handover command is then communicated to the MIH middleware  250 . At  904 , WCDMA quality of service (QoS) is mapped to WiBro QoS. At  905 , the MIH middleware  250  acts to power down the WCDMA modem  230 . The MIH middleware sends a LINK_ACTION_REQUEST message  906  to the WCDMA modem  230 , which at  907  enters low power mode in receive mode only. The WCDMA modem  230  may send a LINK_ACTION_CONFIRM message  908  to the MIH middleware  250 . 
     At  910 , the MIH middleware  250  performs a switch to WiBro. A LINK_ACTION_REQUEST message  911  is sent by the MIH middleware  250  to the WiBro modem  220 . At  912 , the WiBro modem  220  powers on at the transmitter (Tx) side. The WiBro modem  220  sends a LINK_ACTION_CONFIRM message  913  to the MIH middleware  250 . The MIH middleware  250  then sends a C-NEM-REQ(REG) message  915  to the WiBro modem  220 . At  914 , the WiBro modem  220  registers with the WiBro network. The WiBro modem  220  responds to the C-NEM-REQ(REG) message  915  by sending a confirmation (OK) message  916  to the MIH middleware  250 . The MIH middleware  250  sends a C-SFM-REQ(CREATE) message  917  to the WiBro modem  220 . The WiBro modem  220  creates a new QoS service flow. The WiBro modem  220  responds to the C-SFM-REQ(CREATE) message  917  by sending a confirmation (OK) message  918  to the MIH middleware  250 . 
     At the conclusion of the procedure depicted in  FIG. 8 , State Three  990  is achieved. 
       FIG. 10  is a functional block diagram of a handover trigger and execution finish procedure for WCDMA to WiBro handover in accordance with an embodiment. The WTRU  200  includes the MIH middleware  250 , WCMDA modem  230 , and WIBRO modem  220 . The WiBro modem  220  communicates with the IP stack  1050 . The IP stack  465  communicates via IP with the MIH server  480  and the FA server  1055 . The IP stack  465  can be configured to use UDP or TCP in the transport layer. The procedure of  FIG. 10  may be begun when State Three  990  has been achieved. 
     At  1001 , the MIH middleware  250  acts to update a Mobile IP binding. Mobile IP registration information  1002  is communicated between the MIH middleware  250  and the WiBro modem  220 . At  1003 , discovery in conjunction with the FA server  1055  is performed, and a Mobile IP binding update is performed. The actions of  1003  are performed via the IP stack  1050 . At  1004 , the MIH middleware  250  acts to send an MIH Switch Response. At  1006 , the WiBro modem  220  sends an MIH switch response to the MIH server  480  via the IP stack  1050 . At  1080 , a WiBro data session is in progress. At  1008 , the MIH middleware  250  acts to tear down the WCDMA link. The MIH middleware  250  sends a LINK_ACTION_REQUEST message  1009  to the WCDMA modem  230 . At  1010 , the WCDMA modem  230  turns off WCDMA, and sends a LINK_ACTION_CONFIRM message  1011 . 
     At  1012 , middleware interactions are ended and the procedure of  FIG. 10  concludes. 
       FIG. 11  is a functional block diagram of an exemplary registration procedure for WiFi to WCDMA handover in accordance with an embodiment. The WTRU  200  includes an MIH middleware  250 , WiFi modem  210 , and WCDMA modem  230 . The WiFi modem  210  communicates with an IP stack  1165 . The IP stack  1165  communicates via IP with a DNS  1170 , FA server  1175 , and an MIH server  480 . The IP stack  1165  can be configured to use UDP or TCP in the transport layer. 
     At  1101 , middleware interactions are begun. At  1102 , the MIH middleware  250  acts to start MIH discovery. At  1103 , the WiFi modem  210  communicates an MIH server discovery command via the IP stack  1165  to the DNS  1170 . At  1004 , the MIH middleware  250  acts to obtain an HA address. The MIH middleware  250  sends a Home Agent Address Query message  1105  to the WiFi modem  210 . At  1106 , the WiFi modem  210  communicates a command to query a Mobile IP HA Address to the FA server  1175  via the IP stack  1175 . At  1107 , the MIH middleware  250  acts to start an MIH handover session. At  1109 , the WiFi modem  210  communicates a start MIH session message to the MIH server  480  via the IP stack  1165 . 
     At the conclusion of the procedure depicted in  FIG. 11 , State One  1190  is achieved. 
       FIG. 12  is a functional block diagram of an exemplary detection procedure for WiFi to WCDMA handover in accordance with an embodiment. The WTRU  200  includes an MIH middleware  250 , WiFi modem  210 , and WCDMA modem  230 . The procedure of  FIG. 10  may be begun when State One  1190  has been achieved. 
     As seen in  1201 , a WiFi session is ongoing. At  1202 , the MIH middleware  250  acts to request periodic reporting of ObjectIDs (OIDs) related to message strength. The MIH middleware sends  250  a WiFi Measurement Request message  1203  to the WiFi modem  210 . At  1204 , the WiFi modem  210  periodically sends a signal strength report. At  1205 , the WiFi modem  210  communicates signal strength information via a WiFi Measurement Report message  1206  to the MIH middleware  250 . At  1207 , the MIH middleware  250  uses the signal strength data to predict the end of WiFi coverage. At  1208 , in response to a prediction of the end of WiFi coverage, the MIH middleware  250  acts to start the WCDMA modem  230  for potential handover. The MIH middleware  250  sends a start message (AT+CFUN)  1209  to the WCDMA modem  230 . At  1210 , the WCDMA modem  230  starts in idle mode. After starting in idle mode, the WCDMA modem  230  sends a confirmation (OK) message  1211 . At  1212 , the WiFi modem  210  continues to provide signal strength information to the MIH middleware  250 . This is performed by communicating a WiFi Measurement Report message  1213 . At  1214 , the MIH middleware  250  continues to request signal quality information periodically. This is performed by sending a signal quality request message (AT+CSQ)  1215 . At  1216 , the WCDMA modem  230  periodically reports requested WCDMA signal strength information. This is performed by sending a signal strength response (AT+CSQ−&lt;&lt;rssi&gt;, &lt;ber&gt;) message  1217 . 
     At the conclusion of the procedure depicted in  FIG. 12 , State Two  1290  is achieved. 
       FIG. 13  is a functional block diagram of an exemplary handover and execution start procedure for WiFi to WCDMA handover in accordance with an embodiment. The WTRU  200  includes an MIH middleware  250 , WiFi modem  210 , and WCDMA modem  230 . The WiFi modem  210  communicates with an IP stack  1165 . The IP stack  1165  communicates via IP with the MIH server  480 . The IP stack  1165  can be configured to use UDP or TCP in the transport layer. The procedure of  FIG. 13  may be begun when State Two  1290  has been achieved. 
     At  1301 , the MIH middleware  250  acts to send a measurement report to the MIH server  480  when thresholds sets by the MIH server have been crossed. Thresholds may be communicated from the MIH server to the MIH middleware via a MIH_LINK_CONFIGURE_THRESHOLDS command. At  1302 , the WiFi modem  210  communicates a signal strength report to the MIH server  480  via the IP stack  1165 . In response to the report, the MIH server  480  may begin a handover. At  1303 , the WiFi modem receives a handover command from the MIH server  1303 . The WiFi modem  210  then sends the command to the MIH middleware  250 . 
     At  1304 , WiFi quality of service (QOS) is mapped by the MIH middleware  250  to WCDMA QoS. This is performed by the creation of a new PDP context in the WCDMA modem  230  and by specifying a WCDMA Qos Profile. To create a new PDP context, a Create New PDP Context message (AT+CGDCONT)  1305  is communicated to the WCDMA modem  230  by the MIH middleware  250 . At  1306 , the WCDMA modem  230  creates a new PDP context. The WCDA modem  230  then sends a confirmation (OK) message  1307  to the MIH middleware  250 . The MIH middleware  250  sends a profile specification (AT+CGEQREQ) message  1308  to the WCDMA modem  230 . At  1309 , the WCDMA modem  230  stores the QoS profile for the PDP context. The WCDMA modem  230  then sends a confirmation (OK) message  1301  to the MIH middleware  250 . 
     At  1311 , the MIH middleware  250  acts to switch to WCDMA. The MIH middleware  250  sends a Packet-Switched (PS) Attach (AT+CGATT) message to the WCDMA modem  230 . At  1313 , the WCDMA modem  230  goes to Connected Mode (CELL_DCH state). The WCDMA modem  230  sends a confirmation (OK) message  1314  to the MIH middleware  250 . The MIH middleware  250  sends a network registration status (AT+CGATT?) message  1315  to the WCDMA modem  230 . At  1316 , the WCDMA modem  230  reports a change in network registration status by sending a registration status code message  1317 . The MIH middleware  250  sends an Activate PDP Context (AT+CGACT) message  1318  to the WDMCA modem  230 . At  1319 , the WCDMA modem  230  activates multiple PDP contexts and establishes a radio access bearer (RAB). The WCDMA modem  230  sends a confirmation (OK) message  1320  to the MIH middleware  250 . The MIH middleware  250  then sends a Request Current Setting (AT+CGEQREQ?) message  1321  to the WCDMA modem  230 . At  1322 , the WCDMA modem  230  returns the current setting for each defined context. This is performed by sending a current setting message  1323  to the MIH middleware  250 . 
     At the conclusion of the procedure depicted in  FIG. 13 , State Three  1390  is achieved. 
       FIG. 14  shows a functional block diagram of an exemplary handover finish execution procedure for WiFi to WCDMA handover in accordance with an embodiment. The WTRU  200  includes an MIH middleware  250 , WiFi modem  210 , and WCDMA modem  230 . The WCDMA modem  230  communicates with IP stack  465 . The IP stack  465  communicates via IP with the MIH server  480  and FA server  475 . The IP stack  465  can be configured to use UDP or TCP in the transport layer. The procedure of  FIG. 14  may be begun when State Three  1390  has been achieved. 
     At  1401 , the MIH middleware  250  enters a data state. The MIH middleware  250  sends an AT+CGDATA message  1402  to the WCDMA modem  230 . At  1403 , the WCDMA modem sets up a packet-switched (PS) session. A connect message  1404  is then communicated to the MIH middleware  250 . At  1405 , the MIH middleware acts to start a Mobile IP binding update. It sends a Mobile IP registration initiation message  1406  to the WCMDA modem  230 . At  1407 , discovery in conjunction with the FA server  1055  is performed, and a Mobile IP binding update is performed. The actions of  1407  are performed via the IP stack  465 . At  1408 , the MIH middleware  250  sends a send MIH switch response to the WCDMA modem  230 . At  1409 , the WCDMA modem  230  sends the MIH switch response to the MIH server  480  via the IP stack  465 . At  1410 , the MIH middleware  250  sends a link switch command to tear down the WiFi link. This is performed by sending a LINK_ACTION_REQUEST message  1411  to the WiFi modem  210 . At  1412 , the WiFi modem  210  turns off WiFi. Then the WiFi modem  210  sends a LINK_ACTION_CONFIRM message  1413  to the MIH middleware  250 . At  1415 , the middleware interactions are ended and the procedure of  FIG. 14  concludes. 
       FIG. 15  is a functional block diagram of a registration procedure for WCDMA to WiFi handover in accordance with an embodiment. The WTRU  200  includes an MIH middleware  250 , WCDMA modem  230 , and WiFi modem  210 . The WCDMA modem  230  communicates with IP stack  465 . The IP stack  465  communicates via IP with the MIH server  480 , FA server  475 , and DNS  470 . The IP stack  465  can be configured to use UDP or TCP in the transport layer. 
     As seen in  1501 , a PDP context is activated and IP connectivity has been set up. At  1502 , MIH middleware interactions are begun. At  1504 , the MIH middleware  250  acts to start MIH discovery. At  1503 , the WCDMA modem  230  acts to perform MIH server discovery by sending a request to the DNS  1470  via the IP stack  465 . At  1507 , the MIH middleware  250  acts to obtain a Home Agent IP address. This is performed by sending a Home Agent Address Query message  1506  to the WCDMA modem  230 . At  1505 , the WCDMA modem  230  queries the FA server  475  via the IP stack  465  for a Mobile IP HA address for the WTRU. At  1509 , the MIH middleware  1506  acts to start an MIH session. The MIH session may include capability, discovery, registration, event subscription, and link configure functions. At  1508 , the WCDMA modem  230  communicates a start MIH session message to the MIH server  480  via the IP stack  465 . 
     At the conclusion of the procedure depicted in  FIG. 15 , State One  1590  is achieved. 
       FIG. 16  is a functional block diagram of an alternative registration procedure for WCDMA to WiFi handover in accordance with an alternative embodiment. The WTRU  200  includes an MIH middleware  250 , WCDMA modem  230 , and WiFi modem  210 . The WCDMA modem  230  communicates with IP stack  465 . The IP stack  465  communicates via IP with the MIH server  480 . The IP stack  465  can be configured to use UDP or TCP in the transport layer. 
     As seen in  1601 , the WTRU has successfully completed handover to WCDMA and an IP connection has been established. The MIH middleware  250  is already operative. At  1602 , middleware interactions are begun. At  1603 , the MIH middleware  250  acts to register with the MIH server  480 . At  1604 , the WCDMA modem  230  re-registers with the MIH server  480  via the IP stack  465 . At  1605 , the MIH middleware  1605  continues the MIH session. The MIH session may include event subscription and link configuration functions. At  1606 , the WCDMA modem  230  continues the MIH session by communicating to the MIH server  480  via the IP stack  465 . 
     At the conclusion of the procedure depicted in  FIG. 16 , State One  1590  is achieved. 
       FIG. 17  is a functional block diagram of a detection procedure for WCDMA to WiFi handover in accordance with an embodiment. The WTRU  200  includes an MIH middleware  250 , WCDMA modem  230 , and WiFi modem  210 . The WCDMA modem  230  communicates with IP stack  465 . The IP stack  465  communicates via IP with the MIH server  480 . The IP stack  465  can be configured to use UDP or TCP in the transport layer. The procedure of  FIG. 17  may be begun when State One  1590  has been achieved. 
     As seen in  1701 , a WCDMA session is ongoing. At  1702 , the availability of WiFi cells is detected through proprietary system information (SI). At  1703 , the WCMDA modem  230  predicts the availability of WiFi coverage and reports the prediction to the MIH middleware  250 . This is performed by sending a WiFi Available (LINK_DETECTED_INDICATION) message  1704  to the MIH middleware  250 . At  1705 , the MIH middleware  250  acts to inform the MIH server  480  about the availability of WiFi cells. At  1706 , the WCDMA modem  230  informs the MIH server  480  about the availability of WiFi cells by communicating to the MIH server  480  via the IP stack  465 . Performance of  1706  includes communicating a LINK_DETECTED_INDICATION message to the MIH server  480 . At  1707 , the MIH server  480  communicates to the WCDMA modem  230  via the IP stack  465  a list of WiFi cells and reporting thresholds. The WCDMA modem  230  then communicates this information to the MIH middleware  250 . At  1708 , the MIH middleware  250  acts to start the WiFi stack for potential handover and to request a scan report. This is performed by sending a LINK_ACTION_REQUEST message  1709  to the WiFi modem  210 . At  1710 , the WiFi modem turns on in receive mode and beings scanning. The WiFi modem  210  then sends a LINK_ACTION_CONFIRM message  1711  to the MIH middleware  250 . At  1712 , the WiFi modem periodically produces scan results and communicates WiFi measurement reports  1713  to the MIH middleware  250 . At  1714 , the WCDMA modem sends a WCDMA measurement report  1715  to the MIH middleware  250 . 
     At the conclusion of the procedure depicted in  FIG. 17 , State Two  1790  is achieved. 
       FIG. 18  is a functional block diagram of an alternative detection procedure for WCDMA to WiFi handover in accordance with an alternative embodiment. The WTRU  200  includes an MIH middleware  250 , WCDMA modem  230 , and WiFi modem  210 . The WCDMA modem  230  communicates with IP stack  465 . The IP stack  465  communicates via IP with the MIH server  480 . The IP stack  465  can be configured to use UDP or TCP in the transport layer. The procedure of  FIG. 18  may be begun when State One  1590  has been achieved. 
     As seen in  1801 , a WCMDA session is ongoing. As seen in  1802 , periodic registration with the MIH server is performed, allowing the MIH server to be aware of the UMTS cell ID. At  1803 , the MIH server  480  communicates a scan request to the WCDMA modem  230 , the request including a list of WiFi cells and a threshold for reporting. The WCDMA modem  230  sends a MIH_SCAN_REQUEST message to the MIH middleware  250 . At  1805 , the MIH middleware  250  acts to start the WiFI stack for potential handover and to request a scan report. Performance of  1805  includes communicating a LINK_ACTION_REQUEST message  1806  to the WiFi modem  210 . At  1807 , the WiFi modem  210  turns on in receive mode and begins scanning. The WiFi modem  210  communicates a LINK_ACTION_CONFIRM message  1808  to the MIH middleware  250 . At  1810 , the WiFi modem  210  periodically produces requested scan results and communicates WiFi measurement reports  1809  to the MIH middleware  250 . At  1811 , the WCDMA modem  230  sends a WCDMA measurement report  1812  to the MIH middleware  250 . 
     At the conclusion of the procedure depicted in  FIG. 18 , State Two  1790  is achieved. 
       FIG. 19  is a functional block diagram of an alternative detection procedure for WCDMA to WiFi handover in accordance with an alternative embodiment. The WTRU  200  includes an MIH middleware  250 , WCDMA modem  230 , and WiFi modem  210 . The procedure of  FIG. 19  may be begun when State One  1590  has been achieved. 
     As seen in  1901 , a WCDMA session is ongoing. At  1902 , the MIH middleware acts to start the WiFi stack for continuous scanning and to request a scan report. Performance of  1902  includes sending a LINK_ACTION_REQUEST message  1903  to the WiFi modem  210 . At  1904 , the WiFi modem  210  turns on receive mode and begins continuous scanning. The WiFi modem  210  sends a LINK_ACTION_CONFIRM message  1905  to the MIH middleware  250 . At  1906 , the WiFi modem  210  periodically produces requested scan results and communicates WiFi measurement reports  1907  to the MIH middleware  250 . At  1908 , the WCDMA modem sends a WCDMA measurement report  1909  to the MIH middleware  250 . 
     At the conclusion of the procedure depicted in  FIG. 19 , State Two  1790  is achieved. 
       FIG. 20  is a functional block diagram of a handover trigger and execution start procedure for WCDMA to WiFi handover in accordance with an embodiment. The WTRU  200  includes an MIH middleware  250 , WCDMA modem  230 , and WiFi modem  210 . The WCDMA modem  230  communicates with IP stack  465 . The IP stack  465  communicates via IP with the MIH server  480 . The IP stack  465  can be configured to use UDP or TCP in the transport layer. The procedure of  FIG. 20  may be begun when State Two  1790  has been achieved. 
     The MIH server  480  sends MIH_LINK_CONFIGURE_THRESHOLDS commands to the WTRU. At  2003 , when the thresholds set by the command are crossed, the MIH middleware  250  acts to communicate a measurement report to the MIH server  480 . The report is communicated to the MIH sever  480  through the WCDMA modem  230  via the IP stack  465 . At  2008 , the WCDMA modem  230  receives a handover command from the MIH server  480  via the IP stack  465 . The WCDMA modem  230  then communicates the handover command to the MIH middleware  250 . 
     At  2009 , the MIH middleware  250  maps WCMDA QoS to WiFi QoS. At  2010 , the MIH middleware  250  acts to power down the WCDMA modem  230 . Performance of  2010  includes sending a LINK_ACTION_REQUEST message  2011  to the WCDMA modem  230 . At  2012 , the WCDMA modem  230  enters into low power/receive only mode. The WCDMA modem  230  then sends a LINK_ACTION_CONFIRM message  2013  to the MIH middleware  250 . 
     At  2014 , the MIH middleware  250  acts to switch to WiFi. The MIH middleware sends a LINK_ACTION_REQUEST message  2015  to the WiFi modem  210 . At  2016 , the WiFi modem  210  powers on its transmit side and registers with a WiFi network. The WiFi modem  210  then sends a LINK_ACTION_CONFIRM message  2017  to the MIH middleware  250 . The MIH middleware  250  then sends a QoS message  2018  that specifies a QoS to the WiFi modem  210 . At  2019 , the WiFi modem  210  creates a QoS flow. The WiFi modem then transmits a confirmation (OK) message  2020  to the MIH middleware  250 . 
     At the conclusion of the procedure depicted in  FIG. 20 , State Three  2090  is achieved. 
       FIG. 21  is a functional block diagram of a finish handover execution procedure for WCDMA to WiFi handover in accordance with an embodiment. The WTRU  200  includes an MIH middleware  250 , WCDMA modem  230 , and WiFi modem  210 . The WiFi modem  210  communicates with an IP stack  1165 . The IP stack  1165  communicates via IP with FA server  1175  and MIH server  480 . The IP stack  1165  can be configured to use UDP or TCP in the transport layer. The procedure of  FIG. 21  may be begun when State Three  2090  has been achieved. 
     At  2101 , the MIH middleware  250  acts to start a Mobile IP binding update. Mobile IP registration information  2102  is communicated between the MIH middleware  250  and the WiFi modem  210 . At  2103 , the WiFi modem  210  performs discovery in conjunction with the FA server  1175 , and a Mobile IP binding update is performed. The actions of  2103  are performed via the IP stack  1165 . 
     At  2104 , the MIH middleware  250  sends a send MIH switch response to the WiFi modem  210 . At  2105 , the WiFi modem  210  sends the MIH switch response to the MIH server  480  via the IP stack  1165 . As seen in  2106 , a WiFi data session is in progress. 
     At  2107 , the MIH middleware  250  acts to tear down the WCDMA link. This is performed by sending a LINK_ACTION_REQUEST message  2108  to the WCDMA modem  230 . At  2109 , the WCMDA modem  230  turns off WCDMA. The WCDMA modem  230  then sends a LINK_ACTION_CONFIRM message  2110  to the MIH middleware  250 . At  2115 , the middleware interactions are ended and the procedure of  FIG. 21  concludes. 
     Although the features and elements of the present invention are described in the preferred embodiments in particular combinations, each feature or element can be used alone without the other features and elements of the preferred embodiments or in various combinations with or without other features and elements of the present invention. The methods or flow charts provided in the present invention may be implemented in a computer program, software, or firmware tangibly embodied in a computer-readable storage medium for execution by a general purpose computer or a processor. Examples of computer-readable storage mediums include a read only memory (ROM), a random access memory (RAM), a register, cache memory, semiconductor memory devices, magnetic media such as internal hard disks and removable disks, magneto-optical media, and optical media such as CD-ROM disks, and digital versatile disks (DVDs). 
     Suitable processors include, by way of example, a general purpose processor, a special purpose processor, a conventional processor, a digital signal processor (DSP), a plurality of microprocessors, one or more microprocessors in association with a DSP core, a controller, a microcontroller, Application Specific Integrated Circuits (ASICs), Field Programmable Gate Arrays (FPGAs) circuits, any other type of integrated circuit (IC), and/or a state machine. 
     A processor in association with software may be used to implement a radio frequency transceiver for use in a wireless transmit receive unit (WTRU), user equipment (UE), terminal, base station, radio network controller (RNC), or any host computer. The WTRU may be used in conjunction with modules, implemented in hardware and/or software, such as a camera, a video camera module, a videophone, a speakerphone, a vibration device, a speaker, a microphone, a television transceiver, a hands free headset, a keyboard, a Bluetooth® module, a frequency modulated (FM) radio unit, a liquid crystal display (LCD) display unit, an organic light-emitting diode (OLED) display unit, a digital music player, a media player, a video game player module, an Internet browser, and/or any wireless local area network (WLAN) module.