Abstract:
A method and apparatus for facilitating inter-network handover comprises receiving a first network service primitive. The first network service primitive is then mapped to a second network service primitive.

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     This application claims the benefit of U.S. Provisional Application No. 60/820,554, filed Jul. 27, 2006 which is incorporated herein by reference as if fully set forth. 
    
    
     FIELD OF INVENTION 
     The present invention is related to wireless communication systems. More particularly, the present invention is related to a method and apparatus for facilitating inter-network handover. 
     BACKGROUND 
     The IEEE 802.21 group includes mechanisms and procedures that aid in the execution and management of inter-system handovers. In particular, IEEE 802.21 defines three main services that can be accessed by mobility management (MM) applications in order to aid in the management of handover operations and system discovery and system selection. Among these services are event service (ES), information service (IS) and command service (CS). All these services share an important characteristic in that they are delivered using a common uniform interface with respect to prospective users, regardless of the underlying access technologies that support the communication with respect to the core network. 
     The delivery of event services and the generation of commands is typically determined by which event is be triggered based on the prevailing characteristics of the underlying technology. These underlying technologies may be 3GPP, 3GPP2 and IEEE-based wireless local area network (WLAN), (e.g., IEEE 802.11 or 802.16). 
     The IEEE 802.21 specification outlines various triggers and commands that are sent to and received from upper layers. However, the IEEE 802.21 specification does not describe how these events and commands are triggered and generated. There are no procedures or functionality to generate triggers toward upper layers, based on information provided by the 3GPP or 3GPP2 underlying layers. In particular, IEEE 802.21 does not describe how events and commands are triggered and generated when the underlying physical resources are based on 3GPP or 3GPP2 technology. Therefore, it is desirable to provide a method for generating these triggers. 
     SUMMARY 
     The present invention is related to a method and apparatus for facilitating inter-network handover. The method comprises receiving a first network service primitive. The first network service primitive is then mapped to a second network service primitive. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       A more detailed understanding of the invention 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  shows an exemplary wireless communication system including a wireless transmit/receive unit (WTRU), access point (AP), and wireless local area network (WLAN) AP, configured in accordance with the present invention; 
         FIG. 2  is a functional block diagram of the WTRU and AP/WLAN AP of the wireless communication system of  FIG. 1 ; 
         FIG. 3  is a functional block diagram of a mapping model in accordance with the present invention; 
         FIG. 4  is a flow diagram of a method for facilitating inter-network handover in accordance with the present invention; 
         FIG. 5  is an exemplary graphical representation of an IEEE 802.21 command and event service mapping to 3GPP in accordance with the present invention; and 
         FIG. 6  is an exemplary graphical representation of an 802.21 command and event service mapping to 3GPP2 in accordance with the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     When referred to hereafter, 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 hereafter, 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. 
     The present invention is applicable to any wireless communication system including, but not limited to, IEEE 802 technologies, (e.g., 802.11 baseline, 802.11a, 802.11b, 802.11g, 802.11j, 802.11n, 802.16, and 802.21), cellular standards, (e.g., 3GPP or 3GPP2), and other standardized or proprietary wireless technologies, (e.g., Bluetooth, HIPERLAN/2, and the like). 
       FIG. 1  shows an exemplary wireless communication system  100  including a WTRU  110 , an AP  120 , and a WLAN AP  530  configured in accordance with the present invention. In a preferred embodiment, the WLAN AP  530  is connected to a WLAN  540 . As shown in  FIG. 1 , the WTRU  110  is in wireless communication with the AP  120 , which is preferably a third generation partnership project (3GPP) access point, and transitioning during a handover to the WLAN AP  130 . Although only one WTRU  110 , one AP  120 , and one WLAN AP  130  are shown in  FIG. 1 , it should be noted that any number and combination of wireless and wired devices may be included in the wireless communication system  100 . 
       FIG. 2  is a functional block diagram  200  of the WTRU  110  and AP  120 /WLAN AP  130  of the wireless communication system  100  of  FIG. 1 . As shown in  FIG. 2 , the WTRU  110  is in communication with the AP  120 , the WLAN AP  130 , or both, and all are configured to facilitate inter-network handover in accordance with the present invention. In a preferred embodiment of the present invention, the WTRU  110 , AP  120 , and WLAN AP  130  are configured to map events and commands from one network, (e.g., primitives in a 3GPP system), to events and commands in another network, (e.g., primitives in a WLAN network). 
     In addition to the components that may be found in a typical WTRU, the WTRU  110  includes a processor  115 , a receiver  116 , a transmitter  117 , and an antenna  118 . The processor  115  is configured to facilitate inter-network handover in accordance with the present invention. The receiver  116  and the transmitter  117  are in communication with the processor  115 . The antenna  118  is in communication with both the receiver  116  and the transmitter  117  to facilitate the transmission and reception of wireless data. 
     In addition to the components that may be found in a typical AP, the AP  120  includes a processor  125 , a receiver  126 , a transmitter  127 , and an antenna  128 . The processor  115  is configured to facilitate inter-network handover in accordance with the present invention. The receiver  126  and the transmitter  127  are in communication with the processor  125 . The antenna  128  is in communication with both the receiver  126  and the transmitter  127  to facilitate the transmission and reception of wireless data. 
     Similarly, in addition to the components that may be found in a typical WLAN AP, the WLAN AP  130  includes a processor  135 , a receiver  136 , a transmitter  137 , and an antenna  138 . The processor  135  is configured to facilitate inter-network handover in accordance with the present invention. The receiver  136  and the transmitter  137  are in communication with the processor  135 . The antenna  138  is in communication with both the receiver  136  and the transmitter  137  to facilitate the transmission and reception of wireless data. 
       FIG. 3  is a functional block diagram of a mapping model  300  in accordance with the present invention. The mapping model  300  shows schematically a global system for mobile communication enhanced data rate for global evolution radio access network (GERAN)  310 , a universal mobile telecommunications system (UMTS)  320 , and a long term evolution (LTE) system  330 . The GERAN  310  includes a radio resource (RR) protocol layer  311 , a logical link control (LLC) protocol layer  312 , a general packet radio service mobility management (GMM) protocol layer  313 , and a session management (SM) layer  314 . The UMTS  320  includes a non access stratum (NAS) layer  321  and an access stratum (AS) layer  322 . The LTE system  330  includes an evolved universal terrestrial radio access/evolved-CORE (E-UTRA/E-CORE) layer  331 . As shown in  FIG. 3 , events in the GERAN  310 , UMTS  320 , and LTE  330  may be mapped into a media independent handover (MIH)—3GPP—service access point (SAP) layer  340 . Any relevant primitives then supported by a layer within a specific technology may be mapped to a corresponding counterpart within the 802.21 technology without being first interpreted by other layers. 
     Still referring to  FIG. 3 , the services within the different layers of the 3GPP technology may be accessed through the MIH-3GPP-SAP  340 . Preferably, the service is delivered using a primitive defined within the 3GPP specifications and mapped to the corresponding 802.21 counterpart within the MIH function. Alternatively, the 3GPP primitive may be mapped through the use of AT commands or using an API. 
       FIG. 4  is a flow diagram of a method  400  for facilitating inter-network handover in accordance with the present invention. In step  410 , a 3G service primitive is received. The 3G service primitive is then mapped to an IEEE 802.21 primitive or event (step  420 ). Although the method  400  depicts the mapping of a 3G service primitive to an 802.21 primitive or event, it should be noted that the mapping may also occur in the reverse direction and that the primitives are not limited to 3G service primitives and 802.21 primitives. Table 1 below in an exemplary table depicting the mapping of 3GPP primitives to 802.21 events. 
     
       
         
               
               
               
               
             
           
               
                 TABLE 1 
               
               
                   
               
               
                 3GPP 
                 3GPP Service 
                   
                   
               
               
                 Layer 
                 Primitive Descriptions 
                 3GPP Primitive 
                 802.21 Event 
               
               
                   
               
             
             
               
                 RR 
                 Page received by RR layer 
                 GMRR-PAGE 
                 Link Parameter 
               
               
                   
                   
                   
                 Change 
               
               
                   
                 Successful reception of 
                 GRR-DATA 
                 Link Parameter 
               
               
                   
                 data supporting 
                   
                 Change 
               
               
                   
                 specific QoS 
               
               
                 LLC 
                 Peer LLC layer is 
                 LL-ESTABLISH 
                 Link Up/Link 
               
               
                   
                 established 
                   
                 Parameter Change 
               
               
                   
                 Peer LLC layer is 
                 LL-RELEASE 
                 Link Going 
               
               
                   
                 released 
                   
                 Down/Link 
               
               
                   
                   
                   
                 Parameter Change 
               
               
                   
                 LLC Layer 
                 LL-STATUS 
                 Link Down 
               
               
                   
                 unrecoverable error 
               
               
                 GMM 
                 Station is attached 
                 GMMREG-ATACH 
                 Link Parameter 
               
               
                   
                   
                   
                 Change 
               
               
                   
                 Station is detached 
                 GMMREG-DETACH 
                 Link Parameter 
               
               
                   
                   
                   
                 Change 
               
               
                 SM 
                 Data session active 
                 SMSM-ACTIVE 
                 Link Up/Link 
               
               
                   
                   
                   
                 Parameter Change 
               
               
                   
                 Data session is 
                 SMSM- 
                 Link Down/Link 
               
               
                   
                 deactivated 
                 DEACTIVEATE 
                 Parameter Change 
               
               
                   
                 Data session modified 
                 SMSM-MODIFY 
                 Link Parameter 
               
               
                   
                   
                   
                 Change 
               
               
                   
                 Data session 
                 SMSM-STATUS 
                 Link Down 
               
               
                   
                 terminated due to 
               
               
                   
                 unrecoverable error 
               
               
                   
                 PDP Context is active 
                 SMREG-PDP- 
                 Link Up/Handover 
               
               
                   
                   
                 ACTIVATE 
                 Complete/Parameter 
               
               
                   
                   
                   
                 Change/Handover 
               
               
                   
                   
                   
                 Complete 
               
               
                   
                 PDP Context is 
                 SMREG-PDP- 
                 Link Up/Parameter 
               
               
                   
                 modified 
                 MODIFY 
                 Change/Handover 
               
               
                   
                   
                   
                 Complete 
               
               
                   
                 PDP Context is 
                 SMREG-PDP- 
                 Link Going 
               
               
                   
                 deactivated 
                 DEACTIVATE 
                 Down/Link Down 
               
               
                 NAS 
                 Station is attached 
                 GMMREG-ATACH 
                 Parameter Change 
               
               
                   
                 Station is detached 
                 GMMREG-DETACH 
                 Parameter Change 
               
               
                   
                 PDP Context is active 
                 SMREG-PDP- 
                 Link Up/Handover 
               
               
                   
                   
                 ACTIVATE 
                 Complete/Parameter 
               
               
                   
                   
                   
                 Change 
               
               
                   
                 PDP Context is 
                 SMREG-PDP- 
                 Parameter Change/ 
               
               
                   
                 modified 
                 MODIFY 
                 Link Up 
               
               
                   
                 PDP Context is 
                 SMREG-PDP- 
                 Link Down/Link 
               
               
                   
                 deactivated 
                 DEACTIVATE 
                 Parameter Change 
               
               
                   
                 Radio Access Bearer is 
                 RABMSM- 
                 Link Up/Parameter 
               
               
                   
                 activated for data 
                 ACTIVATE 
                 Change/Handover 
               
               
                   
                 transfer 
                   
                 Complete 
               
               
                   
                 Radio Access Bearer is 
                 RABMSM- 
                 Link Down/Link 
               
               
                   
                 deactivated for data 
                 DEACTIVATE 
                 Parameter Change 
               
               
                   
                 transfer 
               
               
                   
                 Radio Access Bearer is 
                 RABMSM-MODIFY 
                 Parameter Change/ 
               
               
                   
                 modified for data 
                   
                 Link Up/Handover 
               
               
                   
                 transfer 
                   
                 Complete 
               
               
                   
                 Radio Access Bearer 
                 RABMSM-STATUS 
                 Link Down 
               
               
                   
                 data transfer error 
               
               
                 AS 
                 Radio Access Bearer 
                 RABMAS-RAB- 
                 Link Up/Handover 
               
               
                   
                 has been activated 
                 ESTABLISH 
                 Complete 
               
               
                   
                 Radio Access Bearer 
                 RABMAS-RAB- 
                 Link Down 
               
               
                   
                 has been released 
                 RELEASE 
               
               
                   
                 AS failure Indication 
                 RABMAS-STATUS 
                 Link Down 
               
               
                   
                 Information regarding 
                 Information 
                 Parameter Change 
               
               
                   
                 geographical area. 
                 Broadcast 
               
               
                   
                 Notification of paging 
                 Paging Request 
                 Parameter Change 
               
               
                   
                 for particular user or 
               
               
                   
                 terminal 
               
               
                   
                 Notification for all 
                 Notification 
                 Parameter Change 
               
               
                   
                 users 
                 Broadcast 
               
               
                   
                 Notification 
                 Notification 
                 Parameter Change 
               
               
                   
                 information for a 
                 Indication 
               
               
                   
                 specific or for many 
               
               
                   
                 user 
               
               
                   
                 UE initiated 
                 Connection 
                 Link Up 
               
               
                   
                 connection 
                 Establishment 
               
               
                   
                 establishment 
               
               
                   
                 Network initiated 
                 IF Initiated 
                 Link Down 
               
               
                   
                 connection release 
                 Connection Release 
               
               
                   
                 Network initiated 
                 IF Side Initiated 
                 Link Up/Link 
               
               
                   
                 Radio Access Bearer 
                 Radio Access Bearer 
                 Detected 
               
               
                   
                 Establishment 
                 Establishment 
               
               
                   
                 Network initiated 
                 IF Side Initiated 
                 Link Down 
               
               
                   
                 Radio Access Bearer 
                 Radio Access Bearer 
               
               
                   
                 Release 
                 Release 
               
               
                   
                 Indication that the 
                 Streamlining 
                 Link Going Down 
               
               
                   
                 connection might be 
                 Require Indication 
               
               
                   
                 aborted unless 
               
               
                   
                 streamlining is done 
               
               
                   
                 Location information 
                 UE location 
                 Parameter Change 
               
               
                   
                 provided by the 
                 information 
               
               
                   
                 network for a specific 
               
               
                   
                 UE 
               
               
                   
                 Connection loss 
                 Connection loss 
                 Link Down 
               
               
                   
                 indications 
                 indication 
               
               
                 E- 
                 The location of the UE 
                 LTE-detached 
                 Parameter Change 
               
               
                 UTRAN/E- 
                 is now know by the 
               
               
                 CORE* 
                 network 
               
               
                   
                 The UE is known to 
                 LTE-idle 
                 Parameter 
               
               
                   
                 the network but not 
                   
                 Change/Link Down 
               
               
                   
                 transport channel is 
               
               
                   
                 established 
               
               
                   
                 Radio resources have 
                 LTE-Active 
                 Link Up/Link 
               
               
                   
                 been established and 
                   
                 Handover Complete 
               
               
                   
                 the UE is able to 
               
               
                   
                 perform uplink and 
               
               
                   
                 downlink transport of 
               
               
                   
                 PDU 
               
               
                   
               
             
          
         
       
     
       FIG. 5  is an exemplary graphical representation of an IEEE 802.21 command and event service mapping to 3GPP  500  in accordance with the present invention.  FIG. 5  shows an MIH user  510 , an MIH functional layer  520 , a mobile network signaling (MNS) layer  530 , and a 3GPP access network  540 . An MIH-SAP layer exists between the MIH user  510  and the MIH functional layer  520 , and the MIH-3GPP-SAP layer exists between the MIH functional layer  520  and the MNS layer  530 . 
     The MNS layer  530  includes an MIH-3GLINK-SAP layer, an 802.21-AT inter-working (IW) function layer, an AT-command interface, and an AT-command-3GPP IWF layer. As shown in  FIG. 5 , a 3GPP primitive is received at the AT-command-3GPP IWF layer which is in communication with the AT-command interface layer and generates an AT command. The AT command may be received by the 802.21-AT IWF layer where it is translated into a 3GPP primitive as expected by the MIH function. Alternatively, the 3GPP primitive could be received directly from the 3GPP access network  540 . Upon receipt of the 3GPP primitive through the MIH-3GLINK-SAP layer, the MIH function  520  maps, or converts, the 3GPP primitive into an 802.21 primitive. Additionally, the MIH function may generate a corresponding media independent primitive toward the MIH user  510 . Conversely, an 802.21 primitive is converted into a 3GPP primitive by a similar reverse process. Accordingly, the 3GPP primitive may be translated into an AT command or directly sent to the 3GPP access network, such as through the use of a function call that implements the 3GPP API. 
       FIG. 6  is an exemplary graphical representation of an IEEE 802.21 command and event service mapping to 3GPP2  600  in accordance with the present invention.  FIG. 6  shows an MIH user  610 , an MIH functional layer  620 , upper layer signaling/point to point protocol (PPP) layer  630 , and a 3GPP2 access network  640 . An MIH-SAP layer exists between the MIH user  610  and the MIH functional layer  620 , and the MIH-3GLINK-SAP layer exists between the MIH functional layer  620  and the upper layer/PPP layer  630 . 
     The upper layer/PPP layer  630  includes an MIH-3GLINK-SAP layer, an 802.21-AT inter-working (IW) function layer, an AT-command interface, and an AT-command-3GPP2 IWF layer. As shown in  FIG. 6 , a 3GPP2 primitive is received at the AT-command-3GPP2 IWF layer which is in communication with the AT-command interface layer and generates an AT command. The AT command may be received by the 802.21-AT IWF layer where it is translated into a 3GPP2 primitive as expected by the MIH function. Alternatively, the 3GPP2 primitive could be received directly from the 3GPP2 access network  640 . Upon receipt of the 3GPP2 primitive through the MIH-3GLINK-SAP layer, the MIH function  620  maps, or converts, the 3GPP2 primitive into an 802.21 primitive. Additionally, the MIH function may generate a corresponding media independent primitive toward the MIH user  610 . Conversely, an 802.21 primitive is converted into a 3GPP2 primitive by a similar reverse process. Accordingly, the 3GPP2 primitive may be translated into an AT command or directly sent to the 3GPP2 access network, such as through the use of a function call that implements the 3GPP API. 
     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.