Abstract:
A method and apparatus for determining whether attach procedures between a wireless transmit/receive unit (WTRU) and a network should proceed based on whether the internet protocol (IP) version, (i.e., packet data protocol (PDP) type), of the WTRU is compatible with the network. In one embodiment, the WTRU receives a network compatibility message from the network which indicates the network&#39;s IP version. If the network&#39;s IP version is determined by the WTRU to be compatible, the WTRU and the network proceed with the attach procedures. In another embodiment, the network receives an attach request message from the WTRU which indicates the IP version of the WTRU. If the IP version of the WTRU is determined by the network to be compatible, the network and the WTRU proceed with the attach procedures. For both embodiments, another network is selected if the IP versions of the WTRU and the network are not compatible.

Description:
CROSS REFERENCE TO RELATED APPLICATION(S)  
       [0001]     This application claims the benefit of U.S. Provisional Application No. 60/592,872, filed Jul. 30, 2004, which is incorporated by reference as if fully set forth herein. 
     
    
     FIELD OF INVENTION  
       [0002]     The present invention is related to a wireless communication system including at least one communication network, (such as a serving general packet radio service (GPRS) support node (SGSN) or a public land mobile network (PLMN)), and at least one wireless transmit/receive unit (WTRU), each supporting a particular internet protocol (IP) version, (i.e., packet data protocol (PDP) type), used to establish IP connectivity, (i.e., PDP context). More particularly, the wireless communication system prevents the WTRU from accessing services provided by a network having an IP version that is not supported by the WTRU.  
       BACKGROUND  
       [0003]     In conventional wireless communication systems, a WTRU can attach to any network regardless of the IP version that the WTRU supports. However, in order to establish IP connectivity, (i.e., PDP context), the IP version of the WTRU must be compatible with the IP version supported by the network. The network may include a Node-B which supports the same IP version as the network.  
         [0004]     If the IP versions of the WTRU and the network are not compatible, the PDP context will be rejected, causing the WTRU to be denied IP multimedia subsystem (IMS) based services after a considerable delay period.  
         [0005]     For example, the standard, (TS 23.221), mandates that a Third Generation Partnership Project (3GPP) IP Multimedia Subsystem (IMS) exclusively operates according to IP version 6 (v6). However, there will be an IP version 4 (v4) based IMS implementation for GPRS networks, and the 3GPP2 IMS is based on IP v4.  
         [0006]     Hence, there is a need for the interworking between different versions of IMSs. A wireless communication method and system for reducing network search time and unnecessary traffic by barring IP incompatible WTRUs from accessing the network is desired.  
       SUMMARY  
       [0007]     The present invention is a method and apparatus for determining whether attach procedures between a WTRU and a network should proceed based on whether the IP version, (i.e., PDP type), of the WTRU is compatible with the network. In one embodiment, the WTRU receives a network compatibility message from the network which indicates the network&#39;s IP version. If the network&#39;s IP version is determined by the WTRU to be compatible, the WTRU and the network proceed with the attach procedures. In another embodiment, the network receives an attach request message from the WTRU which indicates the IP version of the WTRU. If the IP version of the WTRU is determined by the network to be compatible, the network and the WTRU proceed with the attach procedures. For both embodiments, another network is selected if the IP versions of the WTRU and the network are not compatible. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0008]     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:  
         [0009]      FIG. 1  is a block diagram of a wireless communication system including a WTRU which receives a message from at least one network over a broadcast channel indicating an IP version that the network supports in accordance with one embodiment of the present invention;  
         [0010]      FIG. 2  is a block diagram of a wireless communication system including a WTRU which transmits an attach request message to at least one network indicating an IP version that the WTRU supports in accordance with another embodiment of the present invention;  
         [0011]      FIG. 3  is a flow diagram of a process including method steps implemented by the wireless communication system of  FIG. 1 ;  
         [0012]      FIG. 4  is a flow diagram of a process including method steps implemented by the wireless communication system of  FIG. 2 ;  
         [0013]      FIG. 5  is a block diagram of a WTRU used to implement the process of  FIG. 3  in the system of  FIG. 1 ; and  
         [0014]      FIG. 6  is a block diagram of a Node-B/network used to implement the process of  FIG. 4  in the system of  FIG. 2 . 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0015]     Hereafter, the terminology “WTRU” includes but is not limited to a user equipment (UE), a mobile station, a fixed or mobile subscriber unit, a pager, or any other type of device capable of operating in a wireless environment. When referred to hereafter, the terminology “Node-B” includes but is not limited to a base station, a site controller, an access point or any other type of interfacing device in a wireless environment.  
         [0016]     The features of the present invention may be incorporated into an integrated circuit (IC) or be configured in a circuit comprising a multitude of interconnecting components.  
         [0017]      FIG. 1  is a block diagram of a wireless communication system  100  including a WTRU  105  which receives a network capability message  120 ,  125  from at least one network  110 ,  115  over a broadcast channel indicating a particular IP version that the network  110 ,  115  supports in accordance with one embodiment of the present invention. The network  110 ,  115  may include a Node-B (not shown) which supports the same IP version as the network  110 ,  115 .  
         [0018]      FIG. 2  is a block diagram of a wireless communication system  200  including a WTRU  105 ′ which transmits an attach request message  205 ,  210  to at least one network  110 ′,  115 ′ indicating an IP version that the WTRU  105 ′ supports in accordance with another embodiment of the present invention. The network  110 ′,  115 ′ may include a Node-B (not shown) which supports the same IP version as the network  110 ′,  115 ′.  
         [0019]      FIG. 3  is a flow diagram of a process  300  including method steps implemented by the wireless communication system  100 . Referring to  FIGS. 1 and 3 , when the WTRU  105  powers up (step  305 ), the WTRU  105  scans for a control channel (step  310 ) and tunes in and listens to a first broadcast channel in the control channel associated with a first network  110  (step  315 ). The WTRU  105  receives a network capability message  120  sent by the first network  110  over the first broadcast channel indicating a particular IP version, (i.e., PDP type), supported by the first network  110  (step  320 ). The network capability message  120  may include a field having two (2) bits which represent a PDP type. For example, a field having a PDP type “00” may indicate that the first network  110  supports IP version 4, a field having a PDP type “01” may indicate that the first network  110  supports IP version 6, and a field having a PDP type “10” may indicate that the first network  110  supports both IP version 4 and IP version 6.  
         [0020]     In step  325 , the WTRU  105  determines whether the IP version of the first network  110  indicated in the network capability message  120  is the same as the IP version supported by the WTRU  105  (step  325 ).  
         [0021]     If the IP version of the WTRU  105  is determined by the WTRU  105  not to be the same as, (i.e., is not compatible with), the IP version of the first network  110 , the WTRU  105  selects a second network  115 , (i.e., tunes in and listen to a second broadcast channel associated with the second network  115 ), in step  330 , and the WTRU  105  receives a network capability message  125  sent by the second network  115  over the second broadcast channel indicating a particular IP version, (i.e., PDP type), supported by the second network  115  (step  320 ).  
         [0022]     In one embodiment, the WTRU  105  may be directed by the first network  110  to select the second network  115 , wherein the first network  110  has knowledge of another network that is compatible with the IP version of the WTRU  105 . Alternatively, the first network  110  may broadcast a list of neighboring networks in an attempt to assist the WTRU  105  in finding a network that serves the same general area as the first network  110 .  
         [0023]     In another embodiment, the WTRU  105  may include a memory that stores a list of network identifiers. The WTRU  105  may scan the control channel, monitor a plurality of network broadcast channels and select a network having an identifier that matches one of the identifiers in the memory of the WTRU  105 . If more than one match occurs, the WTRU  105  may rely on additional priority information stored in the memory that dictates a preference to select the network having the highest priority. If a match does not occur, the WTRU  105  continues to scan the control channel.  
         [0024]     If the IP version of the first network  110  or the second network  115  is determined in step  325  by the WTRU  105  to be the same as, (compatible with), the IP version of the WTRU  105 , the compatible network  110  or  115  and the WTRU  105  proceed with implementing attach procedures  130 , (i.e., registration), to establish a communication link between the WTRU  105  and the compatible network  110  or  115 .  
         [0025]      FIG. 4  is a flow diagram of a process  400  including method steps implemented by the wireless communication system  200 . Referring to  FIGS. 2 and 4 , when the WTRU  105 ′ powers up (step  405 ), the WTRU  105 ′ scans for a control channel (step  410 ) and tunes in and listens to a first broadcast channel in the control channel associated with a first network  110 ′ (step  415 ). The WTRU  105 ′ sends an attach request message  205  over the broadcast channel indicating a particular IP version, (i.e., PDP type), supported by the WTRU  105 ′ to the first network  110 ′ (step  420 ). The attach request message  205  may include a field having two (2) bits which represent a PDP type. For example, a field having a PDP type “00” may indicate that the WTRU  105 ′ supports IP version 4, a field having a PDP type “01” may indicate that the WTRU  105 ′ supports IP version 6, and a field having a PDP type “10” may indicate that the WTRU  105 ′ supports both IP version 4 and IP version 6.  
         [0026]     In step  425 , the first network  110 ′ receives the attach request message  205  from the WTRU  105 ′ (step  425 ) and determines whether the IP version of the WTRU  105 ′ indicated in the attach request message  205  is the same as the IP version supported by the first network  110 ′ (step  430 ).  
         [0027]     If the IP version of the WTRU  105 ′ is determined by the first network  110 ′ not to be the same as, (i.e., is not compatible with), the IP version of the first network  110 ,′ the network  110 ′ sends a message  215  to the WTRU  105 ′ indicating that the attach request has been denied (step  435 ). The WTRU  105 ′ then tunes in and listens to a second broadcast channel associated with a second network  115 ′ in step  440 . The WTRU  105 ′ may be directed by the first network  110 ′ to select the second network  115 ′, wherein the first network  110 ′ has knowledge of another network that is compatible with the IP version of the WTRU  105 ′.  
         [0028]     In one embodiment, the WTRU  105 ′ may be directed by the first network  110 ′ to select the second network  115 ′, wherein the first network  110 ′ has knowledge of another network that is compatible with the IP version of the WTRU  105 ′. Alternatively, the first network  110 ′ may broadcast a list of neighboring networks in an attempt to assist the WTRU  105 ′ in finding a network that serves the same general area as the first network  110 ′.  
         [0029]     In another embodiment, the WTRU  105 ′ may include a memory that stores a list of network identifiers. The WTRU  105 ′ may scan the control channel, monitor a plurality of network broadcast channels and select a network having an identifier that matches one of the identifiers in the memory of the WTRU  105 ′. If more than one match occurs, the WTRU  105 ′ may rely on additional priority information stored in the memory that dictates a preference to select the network having the highest priority. If a match does not occur, the WTRU  105 ′ continues to scan the control channel.  
         [0030]     If the IP version of the WTRU  105 ′ is determined in step  430  by the network  110 ′ or the network  115 ′ to be network compatible, the WTRU  105 ′ and the compatible network  110 ′ or  115 ′ proceed with attach procedures  220 , (i.e., registration), to establish a communication link between the WTRU  105 ′ and the compatible network  110 ′ or  115 ′ (step  445 ).  
         [0031]      FIG. 5  is a block diagram of a WTRU  500  used to implement the process  300  in the wireless communication system  100 . The WTRU  500  includes an antenna  505 , a receiver  510 , a transmitter  515 , a processor  520  and a memory  525 . When the WTRU  500  powers up, the receiver  510  scans for a control channel via the antenna  505 , and tunes in and listens to a first broadcast channel in the control channel associated with a first network  110 . The receiver  510  receives a network compatibility message  120  sent by the first network  110  over the first broadcast channel indicating a particular IP version, (i.e., PDP type), supported by the first network  110 . The receiver  510  forwards the network compatibility message  120  to the processor  520  which compares the particular IP version supported by the first network  110  with data, stored in the memory  525 , which indicates the IP version of the WTRU  500 .  
         [0032]     If the processor  520  determines that the IP version of the WTRU  500  is not the same as, (i.e., is not compatible with), the IP version of the first network  110 , the processor  520  controls the receiver  510  such that it tunes in and listens to a second broadcast channel associated with a second network  115 . The receiver  510  receives a network compatibility message  125  sent by the second network  115  over the second broadcast channel indicating a particular IP version, (i.e., PDP type), supported by the second network.  
         [0033]     If the IP version of the WTRU  500  is determined by the processor  520  to be the same as, (i.e., compatible with), the IP version of the first network  110  or the second network  115 , the receiver  510 , the processor  520 , the memory  525  and the transmitter  515  are used to proceed with implementing attach procedures  130 , (i.e., registration), to establish a communication link between the WTRU  500  and the compatible network  110 ,  115 .  
         [0034]      FIG. 6  is a block diagram of a Node-B/network  600  used to implement the process  400  in the wireless communication system  200 . The Node-B/network  600  includes an antenna  605 , a receiver  610 , a transmitter  615 , a processor  620  and a memory  625 . The receiver  610  receives an attach request message  205  from the WTRU  105 ′ over the broadcast channel via the antenna  605 . The attach request message  205  indicates a particular IP version, (i.e., PDP type), supported by the WTRU  105 ′. The receiver  610  forwards the attach request message  205  to the processor  620  which compares the particular IP version supported by the WTRU  105 ′ with data, stored in the memory  625 , which indicates the IP version of the Node-B/network  600 .  
         [0035]     If the processor  620  determines that the IP version of the Node-B/network  600  is not the same as, (i.e., is not compatible with), the IP version of the WTRU  105 ′, the processor  620  controls the transmitter  615  to send a message  215  indicating that the attach request has been denied.  
         [0036]     If the IP version of the WTRU  105 ′ is determined by the processor  620  to be the same as, (i.e., compatible with), the IP version of the Node-B/network  600 , the receiver  610 , the processor  620 , the memory  625  and the transmitter  615  are used to proceed with implementing attach procedures, (i.e., registration), to establish a communication link between the WTRU  105 ′ and the Node-B/network  600 .  
         [0037]     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.