Abstract:
The present disclosure provides a method and system for passing information required by a wireless procedure in a hybrid wireless network ( 300 ) before the procedure is invoked, the hybrid wireless network ( 300 ) having at least one radio access network ( 304, 306, 307 ) based on a first technology and a core network ( 302 ) based on a second technology. The hybrid network ( 300 ) implements a special mobile switching center ( 308 ) to be a “double agent” passing information between the mobile terminal ( 310, 320, 364 ) and entities in its core network ( 302 ). In the context of messaging, the message contents may be encoded, packaged, and decoded appropriately. The present disclosure does not introduce any changes to telecommunication standards such as the GSM and CDMA standards governing the messaging process.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS  
       [0001]     The present application claims the benefit of the filing date of U.S. provisional patent application Ser. No. 60/372,529, attorney docket no. 29981.37, filed on 15 Apr. 2002. 
     
    
     TECHNICAL FIELD  
       [0002]     The invention relates in general to voice and data communications, and in particular to a system and method to conduct authentication in a hybrid wireless network.  
       BACKGROUND INFORMATION  
       [0003]     A typical wireless network is composed of two sub-networks: a Radio Access Network (RAN) which handles radio related issues such as assigning radio resources to a mobile terminal (or “mobile” in short) upon request for services, and a Core Network (CN) which links the mobile user to wireline networks. Current specifications of wireless networks require that the RAN and CN have the same wireless technology in order to provide wireless services. These networks may be referred to as “homogeneous networks.” For instance, a GSM mobile will only operate in a wireless network which its RAN and CN are both GSM wireless technology based.  FIG. 1  illustrates a GSM wireless network  100  composed of a GSM RAN  102  and a GSM CN  104 .  
         [0004]     The GSM RAN  102  includes a GSM Mobile Station (MS)  106  that communicates to a GSM Base Station System (BSS)  108  through a GSM radio channel  110 . The GSM BSS  108  includes a GSM Base Transceiver Station (BTS)  110  and GSM Base Station Controller (BSC)  112 .  
         [0005]     The GSM Core Network (CN)  104  includes a GSM Mobile Switching Center (MSC)  120  that is connected to the GSM BSC  112  as well as a GSM Gateway MSC (GMSC)  122  by using SS7 ISUP communications  124 . The GSM GMSC  122  is also connected to the Public Switched Telephone Network (PSTN)  126  by using SS7 ISUP communications  124 . In this figure, a telephone  128  is shown to be connected to the PSTN as an illustration of a calling/called party. In addition, a Serving General Packet Radio Service Node (GPRS) (SGSN)  130  is shown to also be connected to the GSM BSC  112 . Moreover, a GSM Short Message Service Center (SMS-C)  132 , a GSM Home Location Register (HLR)  134  and a GSM Authentication Center (AuC)  136  are all shown to be connected the GSM MSC  120  and the SGSN  130 . Further, a GSM Service Control Point (SCP)  138  connects a GSM Billing System  140  to the GSM MSC  120  and the GSM HLR  134 . The connection from the GSM Billing System  140  and the GSM MSC  120  utilizes IP. Additionally, a Packet Data Network (PDN)  142  is shown connected to the GSM CN  104  through a Gateway GPRS Node (GGSN)  144  utilizing IP communications.  
         [0006]     A disadvantage of this configuration is that, given many wireless technologies that exist today and considering new ones being defined for the future, this is a serious limitation in the wireless service provision to deal with a situation in which a mobile compatible with one wireless technology moves into a wireless network of different technology. Such a configuration prevents the mobile from getting services and limits the mobile&#39;s geographical service area to networks that support a specific wireless technology. The same limitation applies to wireless networks that are CDMA wireless technology based.  
         [0007]      FIG. 2  illustrates such a CDMA2000 based network  200 . The CDMA2000 RAN  201  includes a CDMA2000 MS  202  connected to a CDMA2000 BSS  204  through a CDMA2000 BTS  206 . The CDMA2000 BTS  206  is in turn connected to a CDMA2000 BSC  208 , which connects to a Packet Control Function (PCF)  210 .  
         [0008]     The CDMA2000 CN  212  connects to the CDMA2000 RAN  201  by the CDMA2000 BSC  208  connecting to the CDMA200 MSC  214 . The CDMA2000 MSC  214  is connected to an IS-41 SMS-C  216 , an IS-41 HLR  218 , an IS-41 AuC  220  and an IS-41 SCP  222 . The IS-41 SCP  222  in turn is also connected to the IS-41 HLR  218  and a Store and Forward Service  224 , which in turn is connected to an IS-41 Billing System  226 . In addition, a Packet Data Serving Node (PDSN)  228  is connected to the PCF  210  of the CDMA2000 RAN  200  and a PDN  230 . Moreover, the CDMA2000 MSC  214  connects the CDMA2000 CN  212  to the PSTN  232  and a phone  234 .  
         [0009]     A hybrid wireless network is a wireless network composed of a RAN and a CN of different technologies linked.  FIG. 3  illustrates such a hybrid wireless network  300  including a GSM CN  302 , which may be in communication with a GSM RAN  304  and/or a CDMA RAN  306 . The RAN  304  and  306  communicate with the CN  302  through a Hybrid Mobile Switching Center (HMSC)  308 . This network architecture presents a large advantage in deployment speed and cost reduction over the traditional homogeneous wireless networks discussed previously. One of the problems solved is to enable a mobile terminal in one of the RANs  304  or  306  and certain network entities in the CN  302  to exchange message contents without being obstructed by the differences in the technologies involved (e.g., message encoding and decoding schemes).  
         [0010]     For example, in most wireless networks, wireless services are granted to a mobile after it is authenticated. This process is known as the authentication of a mobile. Different wireless technologies use different procedures and algorithms to perform such an authentication process. For instance, a CDMA mobile operating in a CDMA network generates authentication parameters which are quite different from those generated by a GSM mobile operating in a GSM network. There are currently no known solutions to provide authentication of a mobile operating in a hybrid wireless network.  
         [0011]     What is needed, therefore, is a method and system for providing a solution to pass information and parameters to and from a mobile in a hybrid wireless network in which the RAN technology is CDMA2000 1xEV-DO before the authentication or other procedures requiring certain information from the network is invoked.  
       SUMMARY OF THE INVENTION  
       [0012]     The present disclosure provides a method and system for passing information required by a wireless procedure in a hybrid wireless network before the procedure is invoked, the hybrid wireless network having at least one radio access network based on a first technology and a core network based on a second technology. The hybrid network implements a special mobile switching center to be a “double agent” passing information between the mobile terminal and entities in its core network. In the context of messaging, the message contents may be encoded, packaged, and decoded appropriately. The present disclosure does not introduce any changes to telecommunication standards such as the GSM and CDMA standards governing the messaging process. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0013]      FIG. 1  illustrates a GSM wireless network architecture for providing services to a mobile user.  
         [0014]      FIG. 2  illustrates a CDMA2000 wireless network architecture for providing services to a mobile user.  
         [0015]      FIG. 3  illustrates a hybrid wireless network architecture with a hybrid Mobile Switching Center comprising a RAN using GSM, a RAN using CDMA2000 1xEV-DO, and a RAN using CDMA2000 1xRTT wireless technology, and a CN using GSM wireless technology.  
         [0016]      FIG. 4  is a call flow diagram illustrating a successful authentication of a mobile operated in a CDMS-2000 1xEV-DO RAN and a GSM CN. This figure provides details complementary to  FIG. 5 .  
         [0017]      FIG. 5  is a call flow diagram illustrating a failed authentication of a mobile operated in a CDMS2000 1xEV-DO RAN and a GSM CN. This failure results in denial of service.  
         [0018]      FIG. 6  is a call flow diagram illustrating a failed authentication of a mobile operated in a CDMS2000 1xEV-DO RAN and a GSM CN. This failure does not result in denial of service.  
         [0019]      FIG. 7  is a call flow diagram illustrating another failed authentication of a mobile operated in a CDMS2000 1xEV-DO RAN and a GSM CN. This failure does not result in denial of service.  
         [0020]      FIG. 8  is a call flow diagram illustrating authentication when the mobile roams into a GSM RAN.  
         [0021]      FIG. 9  is a call flow diagram illustrating authentication when the mobile roams into a CDMA2000 1xEV-DO RAN.  
         [0022]      FIG. 10  is a call flow diagram illustrating authentication when the mobile roams into a GSM1x RAN.  
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0023]     For the purposes of the present disclosure, various acronyms are used, the definitions of which are listed below: 
        1xEv-DO Single carrier evolution, data only     1xRTT Single carrier evolution, radio transmission technology     ANSI-41 American National Standards Institute—Cellular Radio Telecommunications Intersystem Operations     AuC Authentication Center     BSC Base Station Center     BSS Base Station System     BTS Base station Transceiver System     CDMA Code Division Multiple Access     CHAP Challenge Handshake Authentication Protocol     CN Core Network     GMSC Gateway MSC     GSM Global System for Mobile communications     HLR Home Location Register     IP Internet Protocol     IMSI International Mobile Subscriber Identity     IS41 Wireless Network conforming to the IS41 standard     ISDN Integrated Services Digital Network     ISUP ISDN User Part (of SS7)     Kc Ciphering Key     Ki Subscriber authentication key     MSC Mobile Switching Center     PSTN Public Switch Telephone Network     RAN Radio Access Network     RAND RANDom Value     SCP Signalling Control Point     SMS-C Short Message Service Center     SRES Signed RESponse or Signature Response     SS7 Signaling System No. 7     T1 Digital communication line that uses time division multiplexing with an overall transmission rate of 1.544 million bits per second.     TCP/IP Transmission Control Protocol/Internet Protocol     VLR Visitor Location Register        
 
         [0055]     Various aspects of the present invention provide a unique system and method for providing authentication of a mobile device in a hybrid wireless network. This patent application is based off of U.S. Provisional Patent 60/372,529 which is hereby incorporated by reference in its entirety. It is understood, however, that the following disclosure provides many different embodiments, or examples, for implementing different features of the invention. Specific examples of components, signals, messages, protocols, and arrangements are described below to simplify the present disclosure. These are, of course, merely examples and are not intended to limit the invention from that described in the claims. Well-known elements are presented without detailed description in order not to obscure the present invention in unnecessary detail. For the most part, details unnecessary to obtain a complete understanding of the present invention have been omitted inasmuch as such details are within the skills of persons of ordinary skill in the relevant art.  
         [0056]      FIG. 3  illustrates a wireless network architecture utilizing a Hybrid Mobile Switching Center (HMSC)  308  to connect a CDMA2000 1xEV-DO RAN  306 , a GSM RAN  304 , and a CDMA2000 1xRTT RAN  307  to the GSM CN  302 . In this example, the HMSC  308  has a centralized call control model for voice and packet data calls. This module allows the HMSC  308  to handle and keep track of all calls for a given mobile phone. In contrast, in a traditional GSM MSC or a CDMA MSC the call control for data and voice are located in different network entities. In this example embodiment, setting-up and controlling a voice or a data call for a mobile user is performed at the HMSC  308 .  
         [0057]     The example network architecture shown in  FIG. 3  illustrates a hybrid network utilizing certain aspects of the present invention. The illustrative network provides both voice and packet data services to mobile stations in either of the two networks. For instance, in the GSM RAN  304 , a GSM mobile unit  310  communicates with a GSM BTS  312  over a GSM radio link  314 . The GSM BTS  312  typically communicates with a GSM BSC  316  using a wired link  318 . The BTS  312  and BSC  316  comprise a base station system or BSS  317 . In the illustrative embodiments, the HMSC  308  communicates with the GSM BSC  316  over a voice link using an SS7 ISUP protocol and over a data link using a Gb interface.  
         [0058]     Similarly, in the CDMA2000 1xEV-DO RAN  306 , a CDMA2000 mobile phone  320  communicates with a CDMA 1xEV-DO BTS  322  over a CDMA radio link  324 . The CDMA 1xEV-DO BTS  322  typically communicates with a CDMA BSC  326  using a wired link  328 . Typically, for voice communications, the CDMA BSC  326  communicates with the HMSC  308  over a link  330  using a variety of protocols, including A1, A2, A5, A8, and A9. The CDMA BSC  326  transfers data to a PCF  332  over a link  334  using A8 and A9 protocols. Thus, data is usually sent by the PCF  332  to the HMSC  308  over a link  336  using the A10 and A11 protocols.  
         [0059]     Similarly, in the CDMA2000 1xRTT RAN  307 , a CDMA2000 mobile phone  364  communicates with a CDMA 1xRTT BTS  366  over a CDMA radio link  368 . The CDMA1xRTT BTS  366  typically communicates with a CDMA BSC  370  using a wired link  372 . Typically, for voice communications, the CDMA BSC  370  communicates with the HMSC  308  over a link  374  using a variety of protocols, including A1, A2, A5, A8, and A9. The CDMA BSC  370  transfers data to a PCF  377  over a link  376  using A8 and A9 protocols. Thus, data is usually sent by the PCF  332  to the HMSC  308  over a link  378  using the A10 and A11 protocols.  
         [0060]     If the core network is a GSM network, as in the illustrative network  300 , the HMSC  308  communicates with the other GSM network components in much the same way a typical MSC would communicate with the GSM network components. For instance, the HMSC  308  may establish links with a GMSC  340 , a SCP  342 , an HLR  344 , a AuC  346 , a PDN  347 , a GGSN  348 , and/or a SMS-C  350 . Similarly, the GMSC  340  may communicate with a PSTN  352  through a T1 link  354  using a SS7 ISUP protocol. The SCP  342  may establish a link  356  with a billing system  358 , and the GGSN  348  may establish a link  360  with the PDN  347 , where the links  356  and  360  uses an IP protocol. Thus, for each connection,  FIG. 3  illustrates an example link and the corresponding communication protocol used to allow communication between typical network entities. As those skilled in the art would recognize, similar communication links may be established if the CN  302  were a CDMA network.  
         [0061]     Thus, for calls established with the GSM mobile  310 , the HMSC  308  acts like a GSM MSC  110  as depicted in  FIG. 1 . For calls established with the CMDA2000 mobile  320 , the HMSC  308  links the CDMA RAN  304  to the GSM CN  302  by translating and mapping CDMA RAN messages initiated in the RAN  304  into GSM CN messages sent to the CN  302 , and GSM messages initiated by the CN  302  into CDMA messages sent to the RAN  306 .  
         [0062]     The HMSC  308  can support voice and packet data call services from mobiles in any type of RAN to any other type of network. For instance the mobile  310  in the GSM RAN  304  can make a call to another mobile (not shown) operating in the CDMA RAN  306 , a telephone  362  connected to the PSTN  352 , or an entity as part of the PDN  347  and other networks that are not illustrated nor discussed in this disclosure for reasons of simplicity and clarity. The HMSC  308  is shown in communication with two RANs of different technologies, however as would be clear to one skilled in the art, the present invention also applies in situations where the HMSC  308  is in communication with one or more RANs of same technology.  
         [0063]     Wireless services are granted to a mobile phone after the mobile phone is “authenticated.” Different wireless technologies use different procedures and algorithms to perform such an authentication process. For instance, the GSM mobile phone  310  operating in the GSM RAN  304  generates authentication parameters which are different from those generated by the CDMA mobile phone  320  operating in the CDMA RAN  306 . Thus, one aspect of the present invention solves this problem by providing for a method of authentication of a mobile terminal in a hybrid wireless network, the hybrid wireless network having at least one radio access network (RAN) based on a first technology (e.g. CDMA) and a core network (CN) based on a second technology (e.g., GSM). Generally, the method comprises: requesting a registration of the mobile terminal from the RAN; passing predetermined parameters for the authentication by the CN through a HMSC to the mobile terminal using messages conforming to the first technology, the parameters conforming to the second technology; invoking an authentication process by the mobile terminal using the passed parameters; and informing the HMSC of the CN for the authentication of the mobile terminal.  
         [0064]     A one-way hash function generates a fixed-length number output—called the hash value—given an arbitrary input. Secure one-way hash functions have the character that it is unfeasible to determine their input given their output. A key-dependent one-way hash function requires a key to calculate the hash value from the input. A typical use of a key dependent secure one-way hash function would be to verify the authenticity of a communicating entity. For instance, if entity A and entity B both know a private key and a key dependent secure one-way hash function, entity A can verify the authenticity of entity B by sending an arbitrary input to B and requesting entity B to return the hash value of this input calculated using the mutually known key dependent secure one-way hash function and the mutually known private key. Upon receiving the hash value from entity B, entity A calculates the hash value for itself and compares its hash value to the hash value from entity B. If the hash values are identical, entity A knows entity B is authentic, because only entity A and entity B know the private key (or others trusted by A and B to share the knowledge of the private key) and this is essential to calculating the correct hash value. If a spurious entity B′ were to attempt to pass itself off as the true entity B it would fail the authentication because it would not know the private key and hence could not calculate the appropriate hash value.  
         [0065]     As is known in the art, a GSM authentication checks the validity of the subscribers subscriber identification module (SIM) card and then decides whether the mobile station should be allowed on a particular network. In a typical GSM network, the authentication process begins when a BSS/MSC/VLR sends the RAND and a GSM Cipering Key sequence (“Kc”), to the mobile unit. The SIM card in the mobile unit uses the RAND, its own private identifier Ki, and the A3 key-dependent secure one-way hash function to generate a signed response (SRES), which is then sent back to the BSS/MSC/VLR. The BSS/MSC/VLR compares the value of SRES received from the AuC with the value of SRES it has received from the mobile station. If the two values of SRES match, authentication is successful and the subscriber joins the network  
         [0066]     This simple GSM authentication scenario does not cover all practical scenarios of authentication in a hybrid network given that the RAN technologies are not always the same as the CN technology. There are special cases to consider including roaming from a RAN of a first type of technology into a RAN of a second type of technology, roaming from a RAN of a second type of technology into a RAN of a first type of technology. Given that the CN only accepts GSM-based authentication parameters, a method is needed to pass the GSM-based parameters between the mobile and the CN over any type of RAN technology. In addition, the present invention introduces a new concept to achieve the appropriate goal. By doing so, scenarios as failed authentication using correct values of RAND (in which case service is denied), and failed authentication using incorrect values of RAND (in which retry procedures are invoked) are considered as well. All of these cases will be discussed in detail below.  
         [0067]      FIG. 4  illustrates an authentication call flow diagram  400  for a mobile in the hybrid network composed of a CDMA2000 1xEV-DO RAN  306  and a GSM CN  302 . In the illustrative embodiment, the participants in the call flow are the Hybrid MSC  308 , the 1xEV-DO BSS  329 , the MS  320 , and the SIM  402 . While the GSM HLR  344  and GSM AuC  346  do not participate in this call flow, they do participate in related call flows and are shown in  FIG. 4  for completeness. Step  404  represents a link control protocol (LCP) negotiation between the MS  320  and the 1xEV-DO BSS  329 . A LCP is used to establish, configure, and test the link communication. Establishment of the link involves each end of the link—the MS  320  and the BSS  329 —negotiating various link options. In step  406  the 1xEV-DO BSS  329  sends a message to the MS  320  to initiate authentication (e.g., in the form of a challenge handshake authentication protocol (CHAP) challenge message). The SIM  402  may use previously stored values of RAND and Kc as well as the internally stored value of Ki in the A3 function to calculate the SRES. Note that in GSM standard, Kc and RAND are sent from the CN to the mobile upon authentication request. In one aspect of the present invention, a new concept is introduced where the RAND and Kc are sent to the mobile during a previous authentication procedure. In step  408  the MS  320  sends a message encapsulating authentication parameters including the value of RAND, the international mobile subscriber identity associated with the MS  320 , the calculated SRES value, and the value of Kc to the 1xEV-DO BSS  329  (e.g., in the form of a CHAP response message encapsulating parameters including name=‘GSMIMSI@operator.com’ and CHAP Password=‘SRES&amp;RAND&amp;Kc’). In step  410  the 1xEV-DO BSS  329  sends a message encapsulating authentication parameters including the value of RAND, the international mobile subscriber identity associated with the MS  320 , the calculated SRES value, and the value of Kc to the Hybrid MSC  308  (e.g., in the form of an Access Request message encapsulating parameters including username=‘GSM IMSI’ and Passwd=‘SRES &amp; RAND &amp; Kc’). The Hybrid MSC  308  may use the IMSI, RAND, and Kc parameters to index into a local database to retrieve a stored SRES value to compare with the SRES parameter which is passed in from the 1xEV-DO BSS  329 . If the Hybrid MSC  308  SRES value agrees with the passed in value of SRES, the MS  320  is authenticated. In step  412  the Hybrid MSC  308  sends a message encapsulating new values of RAND and Kc to the 1xEV-DO  329  (e.g. in the form of an Access Accept message). In step  414  the 1xEV-DO BSS  329  sends a message encapsulating new values of RAND and Kc to the MS  320  (e.g. in the form of a CHAP success message encapsulating new values of RAND and Kc). The MS  320  may store new values of RAND and Kc for future use in authentication procedures.  
         [0068]     Turning to  FIG. 5 , a failed authentication operation is depicted. Step  502  is the LCP negotiation between the MS  320  and the 1xEV-DO BSS  329 . In step  504  the 1xEV-DO BSS  329  sends a message to the MS  320  to initiate authentication (e.g., in the form of a challenge handshake authentication protocol (CHAP) challenge message). The SIM  402  uses previously stored values of RAND and Kc as well as the internally stored value of Ki in the A3 function to calculate SRES. In step  506  the MS  320  sends a message encapsulating authentication parameters including the value of RAND, the international mobile subscriber identity associated with the MS  320 , the SRES value the SIM  402  calculated, and the value of Kc to the 1xEV-DO BSS  329  (e.g., in the form of a CHAP response message encapsulating parameters including name=‘GSMIMSI@operator.com’ and CHAP Password=‘SRES&amp;RAND&amp;Kc’). In step  508  the 1xEV-DO BSS  329  sends a message encapsulating authentication parameters including the value of RAND, the international mobile subscriber identity associated with the MS  320 , the SRES value the SIM  402  calculated, and the value of Kc to the Hybrid MSC  308  (e.g., in the form of an Access Request message encapsulating parameters including username=‘GSM IMSI’ and Passwd=‘SRES &amp; RAND &amp; Kc’). The Hybrid MSC  308  may use the IMSI, RAND, and Kc parameters to index into a local database to retrieve a stored SRES value to compare with the SRES parameter which is passed in from the 1xEV-DO BSS  329 . In this case the Hybrid MSC  308  SRES value disagrees with the passed in value of SRES, and the MS  320  is not authenticated. In step  510  the Hybrid MSC  308  sends a message to the 1xEV-DO  329  (e.g., in the form of an Access Reject message). In step  512  the 1xEV-DO BSS  329  sends a message denying access to the MS  320  (e.g., in the form of a CHAP failure message). Note that no new RAND and Kc values are passed from the Hybrid MSC  308  back to the MS  320 .  
         [0069]     Turning now to  FIG. 6 , a failed authentication operation is depicted. Step  602  is the LCP negotiation between the MS  320  and the 1xEV-DO BSS  329 . In step  604  the 1xEV-DO BSS  329  sends a message to the MS  320  to initiate authentication (e.g., in the form of a challenge handshake authentication protocol (CHAP) challenge message). The SIM  402  uses previously stored values of RAND and Kc as well as the internally stored value of Ki in the A3 function to calculate the SRES. In step  606  the MS  320  sends a message encapsulating authentication parameters including the value of RAND, the international mobile subscriber identity associated with the MS  320 , the SRES value the SIM  402  calculated, and the value of Kc to the 1xEV-DO BSS  329  (e.g., in the form of a CHAP response message encapsulating parameters including name=‘GSMIMSI@operator.com’ and CHAP Password=‘SRES&amp;RAND&amp;Kc’). In step  608  the 1xEV-DO BSS  329  sends a message encapsulating authentication parameters including the value of RAND, the international mobile subscriber identity associated with the MS  320 , the SRES value the SIM  402  calculated, and the value of Kc to the Hybrid MSC  308  (e.g., in the form of an Access Request message encapsulating parameters including username=‘GSM IMSI’ and Passwd=‘SRES &amp; RAND &amp; Kc’). The Hybrid MSC  308  may use the IMSI, RAND, and Kc parameters to index into a local database to retrieve a stored SRES value to compare with the SRES parameter which is passed in from the 1xEV-DO BSS  329 . In the scenario illustrated in  FIG. 6  the values RAND and Kc are not found. In step  610  the Hybrid MSC fetches one or more new RAND, Kc, and SRES value triplets from the GSM HLR  344  and AuC  346 . In step  612  the Hybrid MSC  308  sends a message encapsulating new values of RAND and Kc to the 1xEV-DO  329  (e.g., in the form of an Access Reject message encapsulating new values of RAND and Kc). In step  614  the 1xEV-DO BSS  329  sends a message encapsulating new values of RAND and Kc to the MS  320  (e.g., in the form of a CHAP failure message encapsulating new values of RAND and Kc). The MS  320  may store new values of RAND and Kc for future use in authentication procedures. The MS  320  will retry authentication with the new RAND and Kc values.  
         [0070]     Turning now to  FIG. 7 , a failed authentication operation is depicted. Step  702  is the LCP negotiation between the MS  320  and the 1xEV-DO BSS  329 . In step  704  the 1xEV-DO BSS  329  sends a message to the MS  320  to initiate authentication (e.g., in the form of a challenge handshake authentication protocol (CHAP) challenge message). The SIM  402  uses previously stored values of RAND and Kc as well as the internally stored value of Ki in the A3 function to calculate SRES. In step  706  the MS  320  sends a message encapsulating authentication parameters including the value of RAND, the international mobile subscriber identity associated with the MS  320 , the SRES value the SIM  402  calculated, and the value of Kc to the 1xEV-DO BSS  329  (e.g., in the form of a CHAP response message encapsulating parameters including name=‘GSMIMSI@operator.com’ and CHAP Password=‘SRES&amp;RAND&amp;Kc’). In step  708  the 1xEV-DO BSS  329  sends a message encapsulating authentication parameters including the value of RAND, the international mobile subscriber identity associated with the MS  320 , the SRES value the SIM  402  calculated, and the value of Kc to the Hybrid MSC  308  (e.g., in the form of an Access Request message encapsulating parameters including username=‘GSM IMSI’ and Passwd=‘SRES &amp; RAND &amp; Kc’). The Hybrid MSC  308  may use the IMSI, RAND, and Kc parameters to index into a local database to retrieve a stored SRES value to compare with the SRES parameter which is passed in from the 1xEV-DO BSS  329 . In the scenario illustrated in  FIG. 7  there are no RAND, Kc, and SRES triplet stored in the Hybrid MSC  308 . In step  710  the Hybrid MSC fetches one or more new RAND, Kc, and SRES value triplets from the GSM HLR  344  and AuC  346 . In step  712  the Hybrid MSC  308  sends a message encapsulating new values of RAND and Kc to the 1xEV-DO  329  (e.g., in the form of an Access Reject message encapsulating new values of RAND and Kc). In step  714  the 1xEV-DO BSS  329  sends a message encapsulating new values of RAND and Kc to the MS  320  (e.g., in the form of a CHAP failure message encapsulating new values of RAND and Kc). The MS  320  may store new values of RAND and Kc for future use in authentication procedures. The MS  320  will retry authentication with the new RAND and Kc values.  
         [0071]     Turning now to  FIG. 8  we have an illustrative call flow for mobile authentication when the mobile roams into a GSM RAN. In this case the MS  320  changes mode to GSM mode. Now the standard GSM authentication procedure applies. In step  802  the Hybrid MSC  308  sends an authentication request message bearing RAND and Kc parameters to the GSM BSS  317 . The GSM BSS  317  forwards this authentication request to the MS  320  The SIM  402  uses the RAND and Kc which were received by the MS  320  in the authentication request message as well as the internally stored value of Ki in the A3 function to calculate the SRES. The MS  320  sends an authentication response message bearing the calculated SRES value to the GSM BSS  317 . The GSM BSS  317  forwards this authentication response message to the Hybrid MSC  308 . The SRES value sent by the MS  320  is compared to the SRES value stored in the VLR at the Hybrid MSC  308 . If the values match, authentication succeeds.  
         [0072]     Turning now to  FIG. 9  we have an illustrative call flow for mobile authentication when the mobile roams into a 1xEV-DO RAN. In this case the mobile changes mode to 1xEV-DO mode, and then the authentication scenarios are similar to those already described by  FIG. 4  through  FIG. 7 .  
         [0073]     Turning now to  FIG. 10  an illustrative call flow is shown for mobile authentication when the mobile roams into a GSM1x RAN. GSM1x is a later version of GSM. In this case the mobile changes mode to GSM1x mode, and then the authentication proceeds according to standard GSM1x authentication scenarios.  
         [0074]     In the present disclosure, the messages CHAP Response and Access Request are used to carry the necessary GSM information from the mobile to the network, and the message Access Accept, Access Reject, CHAP Success, and CHAP Failure are used to carry the information from the network to the mobile. In this patent application “pass-through messages means that the information encapsulated in these messages is carried transparently over the 1xEv-DO RAN. That is, none of the entities in the RAN act upon the information encapsulated in these messages, but simply forward them to the next entity until the mobile is reached or the HMSC is reached. In this patent application “encapsulate” means to intercalate information within a message, thereby to make the message carry information additional to the mere message type. In this patent application the term “packaging” may be used in the same sense defined above for the term “encapsulate,” and hence “packaging” and “encapsulating” may substitute for one another from place to place in this patent application.  
         [0075]     The above disclosure provides many different embodiments, or examples, for implementing the disclosure. However, specific examples, and processes are described to help clarify the disclosure. These are, of course, merely examples and are not intended to limit the disclosure from that described in the claims. For instance, even if a CHAP Challenge message and procedure is used to describe the disclosure, the present disclosure still applies to any scenario or event that can occur in the wireless network and that causes the mobile or the network to initiate the authentication procedure.  
         [0076]     Additionally, although a dual-mode mobile that can support voice and packet data is used to describe the disclosure, the present disclosure still applies to any multi-mode mobile. Additionally, GSM and CDMA are used as examples to describe the disclosure. It is understood that the disclosure still applies to any authentication scenario between two wireless networks that have the same CN technology but different RAN technologies.  
         [0077]     The present disclosure as described above thus provides an economical method and system for providing an authentication solution to a multi-mode mobile operating in a hybrid network. The present disclosure does not introduce any changes to the GSM and CDMA standards that define the protocols used to communicate between all network entities. Also, the disclosure does not introduce any change to any entity between the HMSC and the mobile.  
         [0078]     In addition, the present disclosure provides a cost effective solution given that it does not introduce any change to existing architectures in the RAN and CN. This is a significant advantage for a network operator or service provider because there is no need for investing capital in upgrading existing equipment. The migration of the services to be supported by the new network can be achieved in a much shorter time and at a lower cost. The method and system described in the present disclosure increases the wireless coverage to operators exponentially, speeds up deployment phase, minimizes deployment expenses, eliminates core network operation expenses and provides higher quality of service for the mobile end user, therefore attracting more subscribers to operators.  
         [0079]     Also, the present disclosure presents a solution to deploy a new radio technology into wireless networks without introducing any change to the core network. This creates a huge advantage for network operators that looking to expand their wireless service coverage of a new radio technology. The present disclosure needs very low cost and short deployment time considering that the core network does not have to be changed whatsoever. By deploying a new radio technology over an existing core network of existing technologies, major advantages are achieved at the radio access network such as higher bit rates. Other advantages are higher network capacity and increase in spectrum efficiency on the radio which leads to the ability of supporting larger number of subscribers and introducing better quality of service to the mobile user end. This means providing larger service coverage area and higher revenues to network operators.  
         [0080]     Moreover, because no changes are made to the existing core network, the present disclosure allows the delivery of all existing CN services to any mobile in its serving area.  
         [0081]     It will also be understood by those skilled in the art that one or more (including all) of the elements/steps of the present disclosure may be implemented using software and hardware to develop the HMSC, which will then be deployed in a wireless network at appropriate locations with the proper connections.  
         [0082]     Furthermore, while the disclosure has been particularly shown and described with reference to the preferred embodiment thereof, it will be understood by those skilled in the art that various changes in form and detail may be made therein without departing from the spirit and scope of the disclosure, as set forth in the following claims.