Abstract:
A method is disclosed to operate a wireless network ( 20 ) with a MS ( 100 ) and includes, in response to detecting that the MS has changed its location in the wireless network, registering the MS with a BS ( 45 ) to indicate the current location of the MS and, in response to the MS registering with the BS, triggering the sending of messages in the wireless network until information that is indicative of the current location of the MS is recorded by an AAA server ( 80 ). The AAA server can be subsequently queried to obtain the current location of the MS, such as when a network initiated data session (NIDS) for the MS is initiated. Also disclosed is a method to page a MS by, in response to the initiation of a NIDS for the MS, querying a home AAA server for a current BS/PCF/PDSN affiliation of the MS and sending a page message to the MS in accordance with the current BS/PCF/PDSN affiliation of the MS.

Description:
TECHNICAL FIELD 
   This invention relates generally to packet data communications systems having mobile nodes and, more specifically, relates to techniques for sending paging messages to a mobile node, in particular a mobile node that is in an Idle state. 
   BACKGROUND 
   The following abbreviations are herewith defined for the purposes of this patent application: 
   3GPP Third Generation Partnership Project 
   AAA Authentication, Authorization and Accounting 
   BSC Base Station Controller 
   BS Base Station 
   BTS Base Transceiver Station 
   CDMA Code Division, Multiple Access 
   CN Correspondent Node 
   CS Circuit Switched 
   GRE Generic Routing Encapsulation 
   HA Home Agent 
   HLR Home Location Register 
   IMSI International Mobile Subscriber Identity 
   IP Internet protocol 
   IWF Inter-Working Function 
   LDAP Lightweight Directory Access Protocol 
   MN Mobile Node 
   MS Mobile Station 
   MSC Mobile Switching Center 
   NAI Network Access Identifier 
   NIDS Network Initiated Data Session 
   PCF Packet Control Function 
   PDSN Packet Data Serving Node 
   PPP Point to Point Protocol 
   PS Packet Switched 
   PZID Packet Zone ID 
   RADIUS Remote Authentication Dial-In User Service 
   RN Radio Network 
   RP Radio Protocol 
   SDU Service Data Unit 
   SPZ Sub-Paging Zone 
   SPZ_ID Sub-Paging Zone Identifier 
   SQL Structured Query Language 
   VLR Visitor Location Register 
     FIGS. 1A and 1B  illustrates major functional components and the interfaces of a conventional wireless network  20  suitable for operation with a MN or MS  100 . Beginning with  FIG. 1A , a source BS  45  includes a BSC  40  and a plurality of BTSs  50 . The BSC  40  includes a SDU function that operates to identify the information transferred between peer layer entities which is not interpreted by supporting lower layer entities. On the voice side the BS  45  is coupled to a MSC  60 , more specifically it is coupled via an A 1  interface (both CS and PS services) to a MSC call control and management function  60 A and via A 2  and A 5  interfaces (CS services only) to a MSC switch  60 B. The MSC  60  is shown coupled to an IWF  61 . The BS  45  may also be coupled via interfaces A 3  (user traffic), A 3  and A 7  (signalling) to a target BS  45 ′, containing an associated BSC  40 ′ and BTSs  50 ′. On the data side the BS  45  is coupled to a PCF  30  via interfaces A 8  (user traffic) and A 9  (signalling). The PCF  30  is a component of the radio access network that controls the transmission of packets between the BS  45  and a PDSN  32 . The PDSN  32  is responsible for the establishment, maintenance and termination of a PPP session towards the MN. It may also assign dynamic IP addresses in addition to supporting Mobile IP functionality. It provides a similar function to the GSN (GPRS Support Nodes) found in the GSM and UMTS networks. The interfaces between the PCF  30  and the PDSN  32  are designated A 10  (user traffic) and A 11  (signalling), and include GRE and R-P sign capability. 
     FIG. 1B  illustrates further aspects of the wireless network  20 . For example, the MSC  60  is shown connected via an IS-41 MAP interface to a VLR  62 , which in turn is coupled via the IS-41 MAP to a SS-7 (signalling system seven) network  63  and thence to a HLR  64 . The PDSN  32  is coupled to an IP network  70 , and through the IP network  70  to a home AAA  80  and to a HA  90  (e.g., a home IP network a home access provider network, or a private network). The AAA  80  is generally a function that is used to identify a user and the user&#39;s privileges, and to record and track that user&#39;s activities. The PDSN  32  can also be coupled to a visited AAA  80 ′, and to one or more broker AAAs  81 . Note that the target BS  45  associated with a target RN is shown to also include a PCF  30 ′ and a PDSN  32 ′, also coupled to the IP network  70 . 
   Those skilled in the art should appreciate that the foregoing description of the wireless network  20  shown in  FIGS. 1A and 1B  is not intended to be an exhaustive study of wireless networks, but has been provided simply to place the ensuing discussion and description of this invention into a technological context and framework. 
   In order to provide an “Always On Service” the network  20  is required to push data to the MS  100 . However, the CDMA network architecture as currently defined by 3GPP-2 does not include a capability for the wireless network  20  to push data to a MS  100  that is on an Idle state or mode. If the MS  100  is instead in the Active/Dormant (i.e., non-Idle) state, the PDSN  32  has knowledge of the location of the Ms  100  because of the RP session with the PCF  30 . 
   However, for a MS  100  in the Idle state there is no corresponding RP session. A data session needs to be initiated by the MS  100  and, at present, there is no defined way for the network  20  to initiate the session set up. As such, it can be appreciated that one of the problems that arise in a network-initiated session set up is to locate the MS  100  in the network  20 . 
   On the voice side of the network the MSC/HLR  60 ,  64  have exact location information for the MS  100 . Thus, when a mobile terminated voice call needs to be delivered the HLR  64  is contacted to obtain the current location information, and the MS  100  is then paged efficiently by the correct group of BTSs  50 . On the data side, however, the packet core network elements have data that needs to be pushed to the MS  100 , but there is no interface to the HLR  64  (as can be seen in  FIG. 1B ). Also, in order to deliver the packet data the correct PDSN  32 , PCF  30  and BSC  40  combination should be selected so that the page messages can be sent out efficiently. 
   It can be noted that even if there were an interface to the HLR  64  from the packet core network elements, the HLR  64  does not have the MS  100  location information in terms of the correct PCF  30  and PDSN  32  combination. 
   There has been a proposal to address this problem between the PCF  30  and the BSC  40  (using the A 8  and A 9  interfaces). Reference in this regard can be made to a document: 3GPP2 cdma2000 TSG-C, entitled “Mobile paging with mobile station sub-paging zone update”, Ke-Chi Jang et al. (Nortel Networks, 2003, C23-20030714-038R3). This document proposes an efficient way to enable a BS  45  to page a MS  100  in a smaller area. It is said that a registration zone is adequate for voice services, but for packet data service the BS  45  may need to track the MS  100  to a smaller sub-paging zone to achieve a more efficient dormant to active transition. To improve the paging with a smaller SPZ, it was proposed to broadcast a SPZ_ID in an overhead message. The MS  100  that supports this feature reports its location on the R-CSCH (Reverse Common Signaling Logical Channel, a logical channel that carries higher layer signaling traffic from the MS to the BS over a common physical channel) when it detects a SPZ change. The service provider configures the size of the SPZ, and all BSs  45  in the same SPZ have the same zone value. Based on the report from the MS  100 , a network  20  with BSC  40  level control can page the MS  100  within the zone where the MS  100  sends the location report over the R-CSCH.  FIG. 2 , based on a figure in the C23-20030714-038R3 document, shows the various possible scenarios. 
   However, an unfulfilled need still exists to enable the data side of the network  20  to obtain the current BSC/PCF/PDSN association of an Idle MN, without requiring that the voice side of the network be contacted. 
   SUMMARY OF THE PREFERRED EMBODIMENTS 
   The foregoing and other problems are overcome, and other advantages are realized, in accordance with the presently preferred embodiments of these teachings. 
   This invention provides for locating the MS in terms of a BSC/PCF/PDSN association by providing the data side of the network with MS location information. This is done by the MS, when in an Idle state, registering autonomously with the network when there is a change in the SPZ_ID or PZID values. 
   The invention provides a technique to determine the exact location of the MS so that the data side of the network can send page messages through the best possible BSC/BTSs, without having to request location information from the voice side of the network, such as from the MSC/HLR. 
   In one aspect this invention provides a method to operate a wireless network with a MS, and includes, in response to detecting that the MS has changed its location in the wireless network, registering the MS with a BS to indicate the current location of the MS and, in response to the MS registering with the BS, triggering the sending of messages in the wireless network until information that is indicative of the current location of the MS is recorded by an AAA server. 
   In another aspect this invention provides a method that operates a wireless network with the MS and includes, in response to detecting that the MS has changed its location in the wireless network, and that the MS is in an Idle state, sending a message from the MS to the BS, the message indicating the current location of the MS, and triggering the sending of further messages in the wireless network from the BS to a PCF, and from the PCF to a PDSN, and from the PDSN to an AAA server, such that information that is indicative of a current BS/PCF/PDSN affiliation of the MS at the current location of the MS is recorded by the AAA server. 
   A further aspect of this invention is a method to operate a wireless network with a MS that includes, in response to receiving a Registration message from the MS at a BS, the Registration message containing a sub-paging zone identifier SPZ_ID, sending further messages in the wireless network from the BS to the PCF, from the PCF to the PDSN, and from the PDSN to the AAA server, such that information that is indicative of a current location of the MS is recorded by the AAA server. The method further includes, in response to an occurrence of a network initiated data session (NIDS) for the MS, querying the AAA server to obtain at least the current location of the MS. 
   Also disclosed is a wireless network operable with a MS. The wireless network includes the BS that is responsive to receiving a Registration message from a MS that contains a sub-paging zone identifier SPZ_ID, for sending a message from the BS to a PCF via an A 8 /A 9  interface. The PCF, in response to receiving the message from the BS, sends a message to a PDSN via an A 10 /A 11  interface. The PDSN, in response to receiving the message from the PCF, sends a message to a home AAA server via one of a Lightweight Directory Access Protocol LDAP interface, or a JAVA/SQL interface, or possibly a modified RADIUS interface that includes change information to be sent asynchronously to the AAA server. The home AAA server records information that is indicative of a current location of the MS, and is responsive to a query received in response to an occurrence of a NIDS for the MS for returning at least the current location of the MS. 
   Also disclosed is MS operable in a wireless network for transmitting a Registration message to a BS, the Registration message containing a sub-paging zone identifier SPZ_ID. In response, the BS sends a message to a PCF. The PCF, in response to receiving the message from the BS, sends a message to a PDSN that, responsive to receiving the message from the PCF, sends a message to a home AAA server. The home AAA server recording information that is indicative of a current location of the MS, and is further responsive to a query received in response to an occurrence of a network initiated data session (NIDS) for the MS, for returning at least the current location of the MS for enabling data to be received by the MS at its current location. 
   Also disclosed is a BS operable in a wireless network for receiving a Registration message from a MS, the Registration message containing a sub-paging zone identifier SPZ_ID. The BS, in response to receiving the Registration message, sends a message to a PCF. The PCF, in response to receiving the message from the BS, sends a message to a PDSN that, responsive to receiving the message from the PCF, sends a message to a home AAA server. The home AAA server recording information that is indicative of a current location of the MS, and is further responsive to a query received in response to an occurrence of a NIDS for the MS, for returning at least the current location of the MS for enabling data to be received by the MS at its current location via the BS. 
   In a still further aspect this invention provides a method to page a MS by, in response to the initiation of a NIDS for the MS, querying a home AAA server for a current BS/PCF/PDSN affiliation of the MS; and sending a page message to the MS in accordance with the current BS/PCF/PDSN affiliation of the MS. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The foregoing and other aspects of these teachings are made more evident in the following Detailed Description of the Preferred Embodiments, when read in conjunction with the attached Drawing Figures, wherein: 
       FIGS. 1A and 1B  are block diagrams that illustrate conventional wireless network functional components and the interfaces between them; 
       FIG. 2  is a diagram from the prior art that shows various zones associated with two BSCs and one MSC; 
       FIG. 3  is a block diagram of a MS coupled the wireless network, and illustrates one suitable embodiment of apparatus for practicing this invention; and 
       FIG. 4  is a signalling diagram that illustrates the operation of the MS and the wireless network in accordance with this invention. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   By way of introduction, and referring to  FIG. 3 , there is shown as a simplified block diagram an embodiment of a wireless communications system that is suitable for practicing this invention. The wireless communications system includes at least one MS  100 .  FIG. 3  also shows an exemplary wireless network  20  having, for example, a PCF/PDSN  30 ,  32  depicted for simplicity as a single node for connecting to a Packet Data Network (PDN) and thence to an IP network  70 , such as the Internet. The wireless network  20  also includes at least one BS  45  containing a BSC  40  or equivalent apparatus, and a plurality of BTSs  50 , that transmit in a forward or downlink direction both physical and logical channels to the MS  100  in accordance with a predetermined air interface standard. A reverse or uplink communication path also exists from the MS  100  to the network  20 , which conveys MS-originated access requests and traffic. A cell  3  is associated with each BTS  50 , where one cell will at any given time be considered to be a serving cell, while an adjacent cell(s) will be considered to be a neighbor cell. Smaller cells (e.g., picocells) may also be available. Also shown is the MSC  60  on the voice side of the network  20 , and an AAA server  80  on the data side. The AAA server  80  is assumed to store a plurality of user profiles  80 A corresponding to individual users of the network  20 . It should be appreciated that the wireless network  20  may be constructed as shown in  FIGS. 1A and 1B , and may thus contain the same interfaces and other, non-illustrated components. 
   The air interface standard can conform to any suitable standard or protocol, and may enable both voice and data traffic, such as data traffic enabling Internet  70  access and web page downloads. The air interface standard may compatible with a 3GPP2-compatible standard, or a code division multiple access (CDMA) air interface standard, such as one known as cdma2000, although this is not a limitation upon the practice of this invention. For example, this invention could be employed in a CDMA 2000-802.11 (WLAN) interworking scenario. 
   The MS  100  typically includes a control unit or control logic, such as a microcontrol unit (MCU)  120  having an output coupled to an input of a display  140  and an input coupled to an output of a keyboard or keypad  160 . The MS  100  may be a handheld radiotelephone, such as a cellular telephone or a personal communicator. The MS  100  could also be contained within a card or module that is connected during use to another device. For example, the MS  100  could be contained within a PCMCIA or similar type of card or module that is installed during use within a portable data processor, such as a laptop or notebook computer, or even a computer that is wearable by the user. 
   The MCU  120  is assumed to include or be coupled to some type of a memory  130 , including a non-volatile memory for storing an operating program and other information, as well as a volatile memory for temporarily storing required data, scratchpad memory, received packet data, packet data to be transmitted, received zone ID information, and the like. At least some of this temporary data can be stored in a buffer  130 A. The operating program is assumed, for the purposes of this invention, to enable the MCU  120  to execute the software routines, layers and protocols required to implement the methods in accordance with this invention, as well as to provide a suitable user interface (UI), via display  140  and keypad  160 , with a user. Although not shown, a microphone and speaker are typically provided for enabling the user to conduct voice calls in a conventional manner, via the BS  45  and the MSC  60 . 
   The MS  100  also contains a wireless section that includes a digital signal processor (DSP)  180 , or equivalent high speed processor or logic, as well as a wireless transceiver that includes a transmitter  210  and a receiver  220 , both of which are coupled to an antenna  240  for communication with the network operator. At least one local oscillator, such as a frequency synthesizer (SYNTH)  260 , is provided for tuning the transceiver. Data, such as digitized voice and packet data, as well as signalling messages are transmitted and received through the antenna  240 . 
   In accordance with this invention it becomes possible, from the data side of the network  20 , to locate the MS  100  by a combination of BTS  50 , BSC  40 , PCF  30  and PDSN  32 . Although not limited thereto, for convenience this invention employs the already-defined identifiers for a BTS  50 , or a group of BTSs  50 , and the controlling BSC  40 , that were referred to above as the SPZ_ID, and for the PCF  30  the already defined PZID (see, again, the above-referenced C23-20030714-038R3 document). In order to identify the position of the MS  100  in the network  20  across the PDSNs ( 30 ,  32 ′) the IP address of the pertinent one of the PDSNs is used as the identifier for the PDSN  32 . 
   A description is now made of a registration procedure on the data side of the network  20 . Reference is also made to  FIG. 4 . 
   Step 1: The MS  100  sends a Registration message to the BS  45 . The sending of the Registration message is triggered by the MS  100  moving to a different SPZ_ID zone and/or a different PZID, as detected by the MS  100  from the downlink message that is broadcast to include the SPZ_ID. The Registration message includes the SPZ_ID received by the MS  100  in the received downlink message that triggered the sending of the Registration message, since it differed from a previous SPZ_ID stored in the buffer memory  130 A of the MS  100 . In the preferred embodiment of this invention the Registration message is sent when the MS  100  is in the Idle state. 
   Step 2: The BS  45  sends an A 9 -Update_Location message to the PCF  30 . The A 9 -Update_Location message includes the IMSI of the MS  100  and the SPZ_ID reported by the MS  100  in the Registration message. 
   Step 3: The PCF  30  selects a PDSN  32  based on a suitable PDSN  32  selection algorithm and forwards the location information to the selected PDSN  32  in an A 11  Update_Location message. This message includes the IMSI, SPZ_ID and PZID information for the MS  100 . 
   Step 4: The PDSN  32  updates a user profile (UP  80 A) stored in the AAA server  80  to reflect the current SPZ_ID, PZID by using a LDAP interface, or a JAVA/SQL interface to the AAA server  80  (JAVA™ is a Trademark of Sun Microsystems, Inc.) LDAP defines a standard for defining a hierarchical directory structure, and a standard interface for accessing these directories. LDAP originated from the X.500 standard. A protocol such as LDAP can be used to access an X.500 directory. It is also within the scope of this invention to use a modified RADIUS interface that includes change information to be sent asynchronously to the AAA server  80 . 
   The AAA server  80 , if this is the home AAA server  80  for the MS  100  stores the SPZ_ID, PZID and the PDSN IP address for indicating the current location of the MS  100 . If the AAA server is not the home AAA server  80 , i.e., it is a visited AAA server  80 ′, it forwards the SPZ_ID, PZID and the PDSN IP address information, along with the and identity of the MS  100  (e.g., the IMSI) to the home AAA server  80  possibly through one or more broker AAA servers  81  (see  FIG. 1B ). 
   As can be appreciated, this invention extends the use of the sub-paging zone information to the A 8 /A 9  and the A 10 /A 11  interface layers. This invention defines the location of the MS  100 , from a data session perspective, to the association of the MS  100  with a certain BS  45 /PCF  30 /PDSN  32  combination. This beneficially aids in solving the network-initiated data session problem for MSs  100  that are roaming, even across PDSNs  32 , by providing the home service network the ability to route the packets to the correct PDSN  32  or PCF  30 . 
   The use of this invention also avoids the need to introduce new protocols between the packet data core network elements (the PDSN  32 /AAA  80 /HA  90 ) and the HLR  60  for determining the location of the MS  100 . As was noted above, even if it is possible to consult the HLR  60  from the data side to determine the location of the MS  100 , the HLR  60  is currently not defined so as to provide information that identifies the correct PDSN  32  with which the MS  100  is currently associated. Further, in that this invention may use existing air link messages, such as the Registration message as specified in the above-referenced document C23-20030714-038R3, there is no change required to the air interface. 
   The foregoing description has provided by way of exemplary and non-limiting examples a full and informative description of the best method and apparatus presently contemplated by the inventor for carrying out the invention. However, various modifications and adaptations may become apparent to those skilled in the relevant arts in view of the foregoing description, when read in conjunction with the accompanying drawings and the appended claims. As but some examples, the use of other similar or equivalent messages and message data elements may be attempted by those skilled in the art. Further, the various functional units and interfaces shown in  FIGS. 1A ,  1 B and  3  may be supplemented or some may be removed, and the various units, functions and interfaces may be referred to by different names. However, all such and similar modifications of the teachings of this invention will still fall within the scope of this invention. 
   Furthermore, some of the features of the present invention could be used to advantage without the corresponding use of other features. As such, the foregoing description should be considered as merely illustrative of the principles of the present invention, and not in limitation thereof.