DETAILED DESCRIPTION

[0029] Referring first to FIG. 1, a communication system, shown generally at 10 , is operable to communicate packet-formatted data with mobile nodes, of which a single mobile node (MN) 12 is shown in the figure. The packet-formatted data is communicated with the mobile node by way of radio links 14 . In the exemplary implementation, the communication system forms an IP (Internet Protocol) communication system operable, e.g., pursuant to IPv4 or IPv6 protocols. While the following description shall be described with respect to the exemplary implementation in which the communication system forms a radio IP communication system, it should be understood that the teachings of the present invention can analogously be implemented in any of many other types of packet-based radio communication systems. And, while the communication system, and the elements forming the communication system, are functionally represented, the functional elements shown here to form the communication system can be implemented in any desired manner, not only as-shown, but also in other manners.

[0030] The communication system includes a core IP network 16 to which various communication devices, of which the correspondent node 18 is exemplary, are coupled. Access network routers (ARs) are also coupled to the Internet backbone. Each access router defines a sub-network. For instance, the left-most (as shown) access router 22 defines a first sub-network 24 - 1 , a center (as shown) access router 22 - 2 defines a second sub-network 24 - 2 , and a right-most (as shown) access router 22 - 3 defines a third sub-network 24 - 3 . Other access routers and corresponding sub-networks can analogously also be represented. And, while not separately shown, the correspondent node forms a node in another sub-network, defined by another access router.

[0031] Each of the sub-networks also defines a radio access network (RAN). The radio access networks, in the exemplary implementation, are co-terminous with the sub-networks 24 and shall be commonly referenced herein. Each of the radio access networks includes a radio resource manager 28 . Here, the left-most radio access network 24 - 1 includes a radio resource manager (RRM) 28 - 1 , the center-most (as shown) radio access network 24 - 2 includes a radio resource manager 28 - 2 , and the right-most (as shown) radio access network 24 - 3 includes a radio resource manager (RRM) 28 - 3 . The radio resource managers 28 are operable, inter alia, to manage, and otherwise control, radio resources of the radio access networks with which the radio resource managers are associated. The radio resource managers of the respective radio access networks/sub-networks 24 are coupled to corresponding access routers of the sub-networks/radio access networks.

[0032] The radio resource managers include apparatus 32 of an embodiment of the present invention. Here, the radio resource manager 28 - 2 is shown to include the apparatus 32 of an embodiment of the present invention. While not separately shown, others of the radio resource managers 28 also include the apparatus 32 . The elements shown to form portions of the apparatus 32 are functionally represented. While, in the exemplary implementation, the elements are implemented, in part, as algorithms executable by processing circuitry, the functions provided by such elements are implementable in any desired manner.

[0033] Here, the apparatus 32 is shown to include an access router-generated signal detector 34 and a broadcast selector 36 . The access router-generated signal detector is operable to detect router advertisements generated by at least the access router located at the radio access network at which the radio resource manager is located. The router advertisements include indicia identifying the sub-network defined by the access router and address configuration information. Other system information can also be embodied in the router advertisements. In an IP-based system, the identifier identifies prefixes of identifiers, and address configuration information provide information on how to create the IP addresses. In an IPv4 protocol scheme, the prefix values identified in the router advertisement include the two left-most identifiers. For instance, if an IP address, identifying a node is 128.132.10.2, the router advertisement includes the ‘prefix’ digits 128 and 132 . The detector 34 detects such values. Indications of such detections are provided by way of the line 38 to the broadcast selector 36 .

[0034] Each of the radio access networks 24 includes a plurality of base transceiver stations 42 . The base transceiver stations 42 each define cells 44 . The cells 44 define coverage areas within which communications with the base transceiver station that define such cells are permitted when a mobile node is positioned therein. Groups of the base transceiver stations define cellular areas collectively forming access network areas. In the radio access network 24 - 2 , the base transceiver stations 42 are grouped into three groups, Group 44 , Group 46 , and Group 48 , defining first, second, and third access network areas, respectively.

[0035] The radio resource manager 28 - 2 is coupled to the base transceiver stations 42 of the respective access network areas. Other radio resource managers of the other radio access networks analogously are coupled to the base transceiver stations positioned at the respective other radio access networks. The radio resource manager is operable to control broadcast of system information upon broadcast channels in the respective ones of the access network areas. And, here, the broadcast selector 36 is operable pursuant to an embodiment of the present invention to cause the system information communicated upon the broadcast channels at the respective access network areas to include the indicia detected by the detector 34 . That is, the broadcast selector causes the signals communicated upon the broadcast channels of the respective access network areas to include the prefix identifiers identifying the sub-network 24 at which the base transceiver stations are located. When a mobile node tunes to the broadcast channel, the mobile node detects the broadcast information that includes the prefix identifier identifying the sub-network at which the base transceiver stations are located, the address configuration information, and any other system information, as appropriate. Thereby, the apparatus 32 facilitates the providing, in a controlled manner, the identity indicia identifying the sub-network in which the mobile node is located and the address configuration information.

[0036] The RRM may provide the information according to a selected scheme. For example, the information is provided at selected intervals, e.g., once every twenty seconds, or on an as-needed basis. In the exemplary implementation, not all of the information the router advertises is broadcast and the information is not broadcast at the same frequency the router advertises them.

[0037] Through operation of an embodiment of the present invention, the apparatus 32 of an embodiment of the present invention selectably provides the indicia identifying the sub-network at which the mobile node is attached, the address configuration information, and any other appropriate system information. The identifying indicia and the address configuration information are provided in a controlled manner upon broadcast channels, here together with system information generated during conventional operation of the radio access network. Radio resources upon the radio link are conserved while also providing the mobile node with information required of the mobile node to form a care/of (C/O) address to permit routing of packet data thereto as the mobile node roams throughout the communication system. In the exemplary positioning shown in the figure, the mobile node is positioned within a cell 44 forming part of the second access network area (PA2) of the radio access network 24 - 2 . The broadcast selector 36 of the apparatus 32 causes the system information broadcast upon the broadcast channel within the second access network area to include indicia identifying both the access network area (PA2), the prefix identifying the sub-network 24 - 2 , and the address configuration information to be used in sub-network 24 - 2 . Such information is used at the mobile node to define a C/O address to the home network associated with the mobile node 12 . The CIO address is accessible by the home agent of the home network of the mobile node. When packet data is to be communicated to the mobile node, the packet data is delivered to the home network of the mobile node and then re-routed to the C/O address identified by the C/O address obtained pursuant to an embodiment of the present invention.

[0038] In a first exemplary implementation, therefore, the router prefix part of the router advertisement and the address configuration information generated by the access router 22 - 2 is detected by the detector and caused by the broadcast selector to be advertised together with a access network area identifier upon the radio link 14 . The broadcasted information besides the regular broadcast information in the wireless system is, for instance, the concatenation of the router prefix value and an access network area identifier, plus the address configuration information. When the mobile node tunes to the broadcast channel, the mobile node need only check whether the part of the received information regarding the access network area identifier has changed. The access network area identifier changes when the mobile node travels out of one access network area and into another access network area. The separate access network areas are formed at a single radio access network or, conversely, are located in separate radio access networks. The mobile node can also check whether the part of the received information regarding the prefix of the router has changed. The prefix of the router and the address configuration information change when the mobile node travels between successive radio access networks and, when doing so, the mobile node performs both an access network area update and a binding update procedure.

[0039] In another implementation, only the access network area identifier is sent upon the broadcast channels. When only the access network area identifier is sent upon the broadcast channels, the mobile node verifies whether the access network area identifier has changed. If so, an access network area update procedure is performed. During the access network area update procedure, the address configuration and the prefix of the router advertisement is provided to the mobile node. Thereafter, the mobile node decides whether a binding update procedure is required to be performed.

[0040] FIG. 2 illustrates a message sequence diagram, shown generally at 62 , representative of signaling generated during operation of an embodiment of the present invention. Here, router advertisements, here represented by the segment 64 are generated at an access router, here the router 22 - 2 , and communicated to a radio resource manager, here the radio resource manager 282 . In the exemplary implementation, the router advertisement is configured to be sent only to the radio resource manager 28 - 2 . Once delivered to the radio resource manager, the access router-generated signal detector 34 detects prefix information and the address configuration information from the router advertisement. Indications of the detected information are provided to the broadcast selector 36 . The broadcast selector forwards the information, here indicated by the segment 68 , to a base transceiver station, and the base transceiver broadcasts the information, indicated by the segment 72 , to the mobile node. The mobile node detects the information and forms a care/of address, here indicated by the block 74 .

[0041] FIG. 3 illustrates a message sequence diagram, shown generally at 76 , of another embodiment of the present invention. Here, the access network router 22 - 2 again generates router advertisements that are communicated, again indicated by the segment 64 , to the radio resource manager 28 - 2 . And, detection of the identifying indicia and the address configuration information contained in the router advertisement is detected by the detector 34 and provided by way of the line 38 to a broadcast selector 36 . The broadcast selector here maintains a record of the identifying indicia contained in the router advertisement. Subsequently, when a mobile node initiates a paging update procedure, here indicated by the segment 78 , with a base transceiver station 42 of the radio access network, the identifying information of the sub-network and the address configuration information is forwarded, indicated by the segment 82 , to the mobile node. The mobile node thereafter selectably initiates a binding update procedure, indicated by the block 84 .

[0042] FIG. 4 illustrates a method, shown generally at 82 , of an embodiment of the present invention by which to provide a mobile node in a radio IP communication system with identifying indicia identifying the sub-network to which the mobile node attaches and the address configuration information. First, and as indicated by the block 84 , detection is made of identifying indicia and the address configuration information contained in a router advertisement. Then, and as indicated by the block 86 , the identifying indicia and the address configuration information are sent to the mobile node. The identifying indicia and the address configuration information are used at the mobile node to create, as indicated by the block 88 , a care/of address identifying the forwarding address of the mobile node in a visited network.

[0043] The previous descriptions are of preferred examples for implementing the invention, and the scope of the invention should not necessarily be limited by this description. The scope of the present invention is defined by the following claims.