Patent Document

RELATED APPLICATION DATA 
       [0001]    This application is related to Provisional Patent Application Ser. No. 60/978,821 filed on Oct. 10, 2007 and 60/979,414 filed on Oct. 12, 2007, and priority is claimed for this earlier filing under 35 U.S.C. §119(e). The Provisional Patent Application is also incorporated by reference into this utility patent application. 
     
    
     TECHNICAL FIELD OF THE INVENTION 
       [0002]    A method for allocating addressing for a mobile node on a communication system using a handover indicator, access type indicator, and other identification fields. 
       BACKGROUND OF THE INVENTION 
       [0003]    IP-based mobile systems provide for communication between at least one mobile node and a wireless communication network. The term “mobile node” includes a mobile communication unit (e.g., mobile terminal, “smart phones”, nomadic devices such as laptop PCs with wireless connectivity, as described in greater detail below). Among other elements, the wireless communication system includes a home network and a foreign network. The mobile node may change its point of attachment to the Internet through these networks, but the mobile node will always be associated with a single home network for IP addressing purposes. The home network includes a home agent and the foreign network includes a foreign agent—both of which control the routing of information packets into and out of their network. 
         [0004]    The mobile node, home agent and foreign agent may be called different names depending on the nomenclature used on any particular network configuration or communication system. For instance, a “mobile node” encompasses PC&#39;s having cabled (e.g., telephone line (“twisted pair”), Ethernet cable, optical cable, and so on) connectivity to the wireless network, as well as wireless connectivity directly to the cellular network, as can be experienced by various makes and models of mobile terminals (“cell phones”) having various features and functionality, such as Internet access, e-mail, messaging services, and the like. Mobile nodes are sometimes called a user equipment, mobile unit, mobile terminal, mobile device, or similar names depending on the nomenclature adopted by particular system providers. Generally, there is also a correspondence node, which may be mobile or fixed, that may be located on the network for communicating with the mobile node. 
         [0005]    A home agent may also be referred to as a Local Mobility Anchor, Home Mobility Manager, Home Location Register, and a foreign agent may be referred to as a Mobile Access Gateway, Serving Mobility Manager, Visited Location Register, and Visiting Serving Entity. The terms mobile node, home agent and foreign agent are not meant to be restrictively defined, but could include other mobile communication units or supervisory routing devices located on the home or foreign networks. Foreign networks can also be called serving networks. 
       Registering the Mobile Node 
       [0006]    Foreign agents and home agents periodically broadcast an agent advertisement to all nodes on the local network associated with that agent. An agent advertisement is a message from the agent on a network that may be issued under the Mobile IP protocol (RFC 2002) or any other type of communications protocol. This advertisement should include information that is required to uniquely identify a mobility agent (e.g. a home agent, a foreign agent, etc.) to a mobile node. Mobile nodes examine the agent advertisement and determine whether they are connected to the home network or a foreign network. 
         [0007]    The mobile node will always be associated with its home network and sub-network for IP addressing purposes and will have information routed to it by routers located on the home and foreign network. If the mobile node is located on its home network, information packets will be routed to the mobile node according to the standard addressing and routing scheme. If the mobile node is visiting a foreign network, however, the mobile node obtains appropriate information from the agent advertisement, and transmits a registration request message (sometimes called a binding update request) to its home agent through the foreign agent. The registration request message will include a care-of address for the mobile node. A registration reply message (also called a binding update acknowledge message) may be sent to the mobile node by the home agent to confirm that the registration process has been successfully completed. 
         [0008]    The mobile node keeps the home agent informed as to its location on foreign networks by registering a “care-of address” with the home agent. The registered care-of address identifies the foreign network where the mobile node is located, and the home agent uses this registered care-of address to forward information packets to the foreign network for subsequent transfer onto the mobile node. If the home agent receives an information packet addressed to the mobile node while the mobile node is located on a foreign network, the home agent will transmit the information packet to the mobile node&#39;s current location on the foreign network using the applicable care-of address. That is, this information packet containing the care-of address will then be forwarded and routed to the mobile node on the foreign network by a router on the foreign network according to the care-of address. 
         [0009]    When mobile nodes move from one foreign network to another foreign network, problems are sometimes encountered with the registration of the care of addressing with the home agent or local mobility anchor. Further, multiple interfaces may be supported on a single or multiple foreign networks, which can include the different communication access types 802.11d, 802.11g, FIRM, WiFi, WiMax, CDMA, or LTE. Problems can be encountered when the mobile node becomes coupled to different access types on a single or multiple networks. Thus, it is a primary objective of this invention to provide addressing support for a mobile node where there is a handover to a new foreign network, a handover to a second access type on the same foreign network (multiple access types are supported on the foreign network), and/or multiple interfaces are supported for connecting a mobile node to a foreign network. 
       SUMMARY OF THE INVENTION 
       [0010]    The present invention solves these problems with a new proxy binding update request and proxy binding acknowledgement messages having new indicators and identification information. Namely, the home agent/local mobility anchor will exchange proxy binding update messages and proxy binding acknowledge messages that include information such as mobile node identification (MN-ID), home network prefix (HNP), but can also include selective information fields such as, access type, handover indicator (HO), and interface identification (interface ID). By including new access type, indicator, and identification information, the local mobility anchor can respond to a binding update request message with a better understanding of the new connectivity request from the mobile node. The proxy binding update request and acknowledgement messages may require new fields or expanded fields for the transmission of the additional information, and the local mobility anchor/home agent will also need to expand its binding cache entry table to support these new information fields. The invention can be implemented using a new protocol application or modified messages from prior registration applications. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0011]    The objects and features of the invention will become more readily understood from the following detailed description and appended claims when read in conjunction with the accompanying drawings in which like numerals represent like elements and in which: 
           [0012]      FIG. 1  is a mobile IP-based communication system as used in the present invention using proxy messages that specify access type fields; 
           [0013]      FIG. 2  is a binding cache entry table that supports these entries for the system shown in  FIG. 1 ; 
           [0014]      FIG. 3  is a mobile IP-based communication system as used in the present invention using proxy messages that specify access type and handover indicator fields; and 
           [0015]      FIG. 4  is a binding cache entry table that supports these entries for the system shown in  FIG. 3 . 
       
    
    
       [0016]    The objects and features of the invention will become more readily understood from the following detailed description and appended claims when read in conjunction with the accompanying drawings in which like numerals represent like element. 
       DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0017]    In  FIG. 1 , the overall architecture of the IP-based mobile system is shown with a mobile mode  125 , a home network  110  and foreign networks  130  and  150 , respectively. As shown in  FIG. 1 , the home network  110  has a home agent or local mobility anchor  113 . The local mobility anchor  113  is coupled to the mobility agent gateway  155  on foreign network  150  by communication link  112 , and local mobility anchor  113  is coupled to the mobility agent gateway  135  on foreign network  130  by communication link  115 . 
         [0018]    The mobility agent gateway  135  is coupled to the mobile node  125  through the radio access system comprised of the base station transceiver  139  coupled to the antenna/transmitter  137  through the wireless communication link  127 . The mobility agent gateway  155  is coupled the mobile node  125  using a second communication access type, such as WiMax or WiFi, which is supported by the interface  141  and wireless communication link  157 .  FIG. 1  also shows a connection to mobile node  125  from the foreign agent  135  through connection  176  and second access interface  177 . This interface is connected to mobile node  125  through wireless communication link  180 . In this embodiment, the communication access type supported by connection interface  177  is the same as the second communication access type supported by interface  141 . This embodiment has a limitation that multiple interfaces may be supported on the networks, but on any given foreign network (such as network  150  or  130 ), only one interface will be supported for each communication access type. 
         [0019]    Mobile node  125  is shown electronically coupled to the foreign networks  150  and  130  via the wireless communication link  157  and  127 , respectively. The mobile node  125 , however, can communicate with any transceiver or access network coupled to a foreign network. That is, communications links  127  and  157  are radio transmitted links, but these links can be composed of any connection between two or more nodes on a network or users on networks or administrative domains. 
         [0020]    The terms Local Mobility Anchor, home agent, and foreign agent may be as defined in the Mobile IP Protocol (RFC 2002), but these agents are not restricted to a single protocol or system. In fact, the term home agent, as used in this application, can refer to a home mobility manager, home location register, home serving entity, or any other agent at a home network  110  having the responsibility to manage mobility-related functionality for a mobile node  125 . Likewise, the term mobility agent gateway, as used in this application, can refer to a foreign agent, serving mobility manager, visited location register, visiting serving entity, or any other agent on a foreign network having the responsibility to manage mobility-related functionality for a mobile node  125 . 
         [0021]    In the mobile IP communications system shown in  FIG. 1 , the mobile node  125  is identified by a permanent IP address. While the mobile node  125  is coupled to its home network  110 , the mobile node  125  receives information packets like any other fixed node on the home network  110 . When mobile, the mobile node  125  can also locate itself on foreign network, such as network  130  or  150 . When located on foreign network  130  or  150 , the home network  110  sends data communications to the mobile node  125  by “tunneling” the communications to the foreign network  130  or  150 . 
         [0022]    The mobile node  125  keeps the local mobility anchor  113  informed of its current location, or foreign network association, by registering a care-of address with the local mobility anchor  113 . Essentially, the care-of address represents the foreign network where the mobile node  125  is currently located. If the local mobility anchor  113  receives an information packet addressed to the mobile node  125  while the mobile node  125  is located on a foreign network  130 , the local mobility anchor  113  will “tunnel” the information packet to foreign network  130  for subsequent transmission to mobile node  125 . 
         [0023]    The foreign agent  135  participates in informing the local mobility anchor  113  of the mobile node  125  current care-of address. The foreign agent  135  also receives information packets for the mobile node  125  after the information packets have been forwarded to the foreign agent  135  by the local mobility anchor  113 . Moreover, the foreign agent  135  serves as a default router for out-going information packets generated by the mobile node  125  while connected to the foreign network  130 . 
         [0024]    The mobile node  125  participates in informing the local mobility anchor  125  of its current location and requests connections to the associated foreign network. When the mobile node  125  transitions to connecting to a different access type on the foreign network or a wholly different foreign network (handover), the mobile node  125  obtains appropriate information regarding the address of the foreign network and/or the foreign agent from an agent advertisement. 
         [0025]    When first connected to the local mobility anchor  113 , mobile node  125  would have created an entry on the binding cache entry table in  FIG. 2  that specified the mobile node identification for the mobile node  125 . The access type field of information is included in the proxy binding update request and the binding cache entry table in  FIG. 2 , with the mobile node identification field.  FIG. 2  is a binding cache entry table  160  that possesses at least column and row entries for the mobile node identification  165  and the access type  167 . Other fields are maintained on the binding cache entry table, but these are the pertinent entries for the consideration of the present invention. 
         [0026]    Because each access type on the networks shown on  FIG. 1  are limited to a single interface from each foreign network, the local mobility anchor will check subsequent proxy binding update requests received from the mobile node  125  to determine if this proxy binding update request has the same access type indicator as previously maintained on the binding cache entry table  160  for that mobile node  125 . If the same access type indicator is found in a proxy binding update request as previously maintained on the binding cache entry table  160  for that mobile node  125 , the local mobility anchor  113  will recognize the situation as a handover of the mobile node  125  to a new foreign network, such as a handover of mobile node  125  from foreign network  130  to foreign network  150 . The local mobility anchor  113  will create a new binding cache entry for the mobile node, and the care-of addressing and home network prefix will be changed to designate the new foreign network as the network where the mobile node  125  can be located, which information will be transmitted to the proper mobility access gateway  135  and the mobile node  125 . 
         [0027]    If the comparison with the information in the proxy binding update request shows a different access type connection for the mobile node  125 , the local mobility anchor will determine if the home network prefix should designate the foreign network where the mobile node  125  was previously located without any indication of a handover to a new foreign network. If that is the case, the entry for the mobile node  125  will be modified on the binding cache entry table to indicate that the mobile node  125  is still connected to the first foreign network  130 , which information will be transmitted to the proper mobility access gateway  135  and the mobile node  125 . 
         [0028]    That is, this comparison may simple show the new connection for the mobile node  125  is to a new access type, as opposed to a handover to a new foreign network. If so, the local mobility anchor  113  will respond to the proxy binding update request with a proxy binding update response having a home network prefix indicator that points to the first foreign network  130 . In this manner, a receipt of new proxy binding update request at the local mobility anchor  113  does not automatically create a new home network prefix for this mobile node, which solves some of the problems with determining when a mobile node is simply connecting to a new access type on the same network or being handed over to a new foreign network. 
         [0029]    In  FIG. 3 , the overall architecture of the IP-based mobile system is shown with a mobile mode  225 , a home network  210  and foreign networks  230  and  250 , respectively. As shown in  FIG. 3 , the home network  210  has a home agent or local mobility anchor  213 . The local mobility anchor  213  is coupled to the mobility agent gateway  255  on foreign network  250  by communication link  212 , and local mobility anchor  213  is coupled to the mobility agent gateway  235  on foreign network  230  by communication link  215 . 
         [0030]    The mobility agent gateway  235  is coupled to the mobile node  225  through the radio access system comprised of the base station transceiver  239  coupled to the antenna/transmitter  237  through the communication link  227 . The mobility agent gateway  255  is coupled to a second access type, such as WiMax or WiFi, through interface  241  coupled to the mobile node  225  by communication link  257 .  FIG. 3  also shows a second connection of the same access type as supported by interface  241  for the connection of the mobile node  225  to foreign agent  255  through connection  276  and second access interface  277 . This interface is connected to mobile node  225  through communication link  280 . 
         [0031]    Mobile node  225  is shown electronically coupled to the foreign networks  250  and  230  via the wireless communication link  257  (or  280 ) and  227 , respectively. The mobile node  225 , however, can communicate with any transceiver or access network coupled to a foreign network. That is, communications links  227 ,  280  and  241  are radio transmitted links, but these links can be composed of any connection between two or more nodes on a network or users on networks or administrative domains. 
         [0032]    The terms Local Mobility Anchor, home agent, and foreign agent may be as defined in the Mobile IP Protocol (RFC 2002), but these agents are not restricted to a single protocol or system. In fact, the term home agent, as used in this application, can refer to a home mobility manager, home location register, home serving entity, or any other agent at a home network  210  having the responsibility to manage mobility-related functionality for a mobile node  225 . Likewise, the term mobility agent gateway, as used in this application, can refer to a foreign agent, serving mobility manager, visited location register, visiting serving entity, or any other agent on a foreign network having the responsibility to manage mobility-related functionality for a mobile node  225 . 
         [0033]    In the mobile IP communications system shown in  FIG. 3 , the mobile node  225  is identified by a permanent IP address. While the mobile node  225  is coupled to its home network  210 , the mobile node  225  receives information packets like any other fixed node on the home network  210 . When mobile, the mobile node  225  can also locate itself on foreign network, such as network  230  or  250 . When located on foreign network  230  or  250 , the home network  210  sends data communications to the mobile node  225  by “tunneling” the communications to the foreign network  230  or  250 . 
         [0034]    The mobile node  225  keeps the local mobility anchor  213  informed of its current location, or foreign network association, by registering a care-of address with the local mobility anchor  213 . Essentially, the care-of address represents the foreign network where the mobile node  225  is currently located. If the local mobility anchor  213  receives an information packet addressed to the mobile node  225  while the mobile node  225  is located on a foreign network  230 , the local mobility anchor  213  will “tunnel” the information packet to foreign network  230  for subsequent transmission to mobile node  225 . 
         [0035]    The foreign agent  235  participates in informing the local mobility anchor  213  of the mobile node  225  current care-of address. The foreign agent  235  also receives information packets for the mobile node  225  after the information packets have been forwarded to the foreign agent  235  by the local mobility anchor  213 . Moreover, the foreign agent  235  serves as a default router for out-going information packets generated by the mobile node  225  while connected to the foreign network  230 . 
         [0036]    The mobile node  225  participates in informing the local mobility anchor  225  of its current location and requests connections to the associated foreign network. When the mobile node  225  transitions to connecting to foreign network  250 , the mobile node  225  obtains appropriate information regarding the address of the foreign network  250  and/or the foreign agent  255  from an agent advertisement. 
         [0037]    When first connected to the local mobility anchor  213 , mobile node  225  would have created an entry on the binding cache entry table in  FIG. 2  that specified the mobile node identification for the first access type. The access type field of information is included in this binding cache entry table in  FIG. 2 , with the mobile node identification field.  FIG. 2  is a binding cache entry table  260  that possesses at least column and row entries for the mobile node identification  265  and the access type  267 . 
         [0038]    In the system shown on  FIG. 3 , multiple access types on a single foreign network  250  are supported by multiple interfaces, such as interface  241  and  277 . Because the correspondence of the same access type on the binding cache entry table of  FIG. 2  may not indicate an inherent handover to a different foreign network from the prior connected foreign network, the proxy binding update request will include a handover indicator for the analysis by the local mobility anchor  213 . 
         [0039]    The handover indicator would include a new field in the transmission packet that would indicate a handover to the same access type on the same foreign network or a handover to a new foreign network. This information could also be indicated by a flag or other indicator to show the type of handover that will be initiated, e.g. flag “ 1 ” equals handover to same access type on same foreign network, flag “ 0 ” equals handover to different foreign network. The new field could also indicate if the handover status is unknown, or this is an initial request for a proxy binding update request. Other fields can be maintained on the binding cache entry table, and the transmission packets may be expanded to accommodate the new access type field of information. 
         [0040]    The local mobility anchor  213  will check subsequent proxy binding update requests received from the mobile node  225  to determine the handover indicator status. If the handover indicator indicates that the mobile node is being connected to a different foreign network, the local mobility anchor  113  will initiate a protocol for a handover of the mobile node  225  to a new foreign network, such as a handover of mobile node  225  from foreign network  250  to foreign network  230 . The local mobility anchor  213  will create a new binding cache entry for the mobile node, and the care-of addressing and home network prefix will be changed to designate the new foreign network as the network where the mobile node  225  can be located, which information will be transmitted to the proper mobility access gateway  235  and the mobile node  225 . 
         [0041]    If the handover indicator indicates that a handover is being requested to different access type connection for the mobile node  225  on the same foreign network  250 , the local mobility anchor  213  will initiate a protocol for designating a home network prefix for the foreign network  250  where the mobile node  225  was previously located without any indication of a handover to a new foreign network. If that is the case, the entry for the mobile node  225  will be modified on the binding cache entry table to indicate that the mobile node  225  is still connected to the first foreign network  250 , which information will be transmitted to the proper mobility access gateway  235  and the mobile node  225 . 
         [0042]    That is, this handover indicator may simply show the new connection for the mobile node  225  is to a new interface for the same access type on the same foreign network  250 , as opposed to a handover to a new foreign network. If so, the local mobility anchor  213  will respond to the proxy binding update request with a proxy binding update response having a home network prefix indicator that points to the first foreign network  250 . In this manner, a receipt of new proxy binding update request at the local mobility anchor  213  does not automatically create a new home network prefix for this mobile node, which solves some of the problems with determining whether a handover of the mobile node care-of addressing is necessary and whether it is necessary to designate a new foreign network or the same foreign network for this care-of addressing for the mobile node. 
         [0043]    As an alternative embodiment that is covered by the scope of the invention, when first connected to the local mobility anchor  213 , mobile node  225  would have created an entry on the binding cache entry table in  FIG. 4  that specified the mobile node identification for the first access type and interface identification information. The access type field of information is included in this binding cache entry table in  FIG. 4 , with the mobile node identification field, and the interface identification information in column  269  would have indicated the specific interface information for interface  241  or  277 .  FIG. 2  is a binding cache entry table  260  that possesses at least column and row entries for the mobile node identification  265 , the access type  267 , and the interface  269 . 
         [0044]    In the system shown on  FIG. 3 , multiple access types on a single foreign network  250  are supported by multiple interfaces, such as interface  241  and  277 . Because the correspondence of the same access type on the binding cache entry table of  FIG. 4  would include additional information that the local mobility anchor would use to analyze whether the proxy binding update request relates to a handover to a different foreign network  230  from the prior connected foreign network  250  or a handover to a different interface for the same access type on the same foreign network  250 . 
         [0045]    In addition to the access type information and the handover indicator described above, the proxy binding update request would include a new field in the transmission packet that would identify the interface that will be used to connect the mobile node to the foreign network. The new field could also indicate if the interface identification is unknown. Other fields can be maintained on the binding cache entry table, and the transmission packets may be expanded to accommodate the new access type field of information. 
         [0046]    The local mobility anchor  213  will check subsequent proxy binding update requests received from the mobile node  225  to determine the handover indicator status. If the access type, handover indicator and interface identification information indicates that the mobile node is being connected to a different foreign network, the local mobility anchor  113  will initiate a protocol for a handover of the mobile node  225  to a new foreign network, such as a handover of mobile node  225  from foreign network  250  to foreign network  230 . The local mobility anchor  213  will create a new binding cache entry for the mobile node, and the care-of addressing and home network prefix will be changed to designate the new foreign network as the network where the mobile node  225  can be located, which information will be transmitted to the proper mobility access gateway  235  and the mobile node  225 . 
         [0047]    If the access type, handover indicator, and interface identification information indicates that a handover is being requested to different access type connection for the mobile node  225  on the same foreign network  250 , the local mobility anchor  213  will initiate a protocol for designating a home network prefix for the foreign network  250  where the mobile node  225  was previously located without any indication of a handover to a new foreign network. If that is the case, the entry for the mobile node  225  will be modified on the binding cache entry table to indicate that the mobile node  225  is still connected to the first foreign network  250 , which information will be transmitted to the proper mobility access gateway  235  and the mobile node  225 . 
         [0048]    That is, the access type, handover indicator, and interface information may simply show the new connection for the mobile node  225  is to a new interface for the same access type on the same foreign network  250 , as opposed to a handover to a new foreign network. If so, the local mobility anchor  213  will respond to the proxy binding update request with a proxy binding update response having a home network prefix indicator that points to the first foreign network  250 . In this manner, a receipt of new proxy binding update request at the local mobility anchor  213  does not automatically create a new home network prefix for this mobile node, which solves some of the problems with determining whether a handover of the mobile node care-of addressing is necessary and whether it is necessary to designate a new foreign network or the same foreign network for this care-of addressing for the mobile node. 
         [0049]    While preferred embodiments of the invention have been shown and described, modifications thereof can be made by one skilled in the art without departing from the spirit and teachings of the invention. The embodiments described herein are exemplary only, and are not intended to be limiting. Many variations and modifications of the invention disclosed herein are possible and are within the scope of the invention.

Technology Category: 5