Abstract:
The present invention is related to FMIPv6 handover method and apparatus for the method in UMTS network. The present invention comprises obtaining lower layer information about a target RNS from a current RNS; obtaining upper layer information about a target core network from a current core network; establishing a tunnel between a current core network and a target core network by using the lower layer information and allocating a target RNS; and after allocation of a target RNS, transmitting a message notifying a target core network of connection to the target RNS and receiving packet data from the target core network. The present invention supports efficient handover in UMTS network by using MIH service and reduces handover delay

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    This application claims the benefit of Korean Application No. 10-2008-0131731, filed Dec. 22, 2008 in the Korean Intellectual Property Office, the disclosure of which is incorporated herein by reference. 
       BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    The present invention is related to a method for FMIPV6 handover in UMTS network and an apparatus for the method. More specifically, the present invention is related to a method for FMIPV6 handover in UMTS network and an apparatus for the method, the UMTS network enabling fast handover by estimating layer 3 handover based on layer 2 information of UMTS network. 
         [0004]    2. Description of Related Art 
         [0005]    In the mobile Internet protocol version 6 (MIPv6), if a mobile node detects a new access point, layer 2 handover is carried out, after which layer 3 handover is carried out. Therefore, MIPv6 can prevent network disconnection due to handover delay encountered when a mobile node carries out handover. 
         [0006]    FMIPv6 (Fast Mobile Internet protocol version 6) is a method for carrying out layer 3 handover before layer 2 handover is occurred, receiving layer 3 information from a current router based on layer 2 information of a target router to hand over. An access network is subject to a different layer 2 handover procedure depending on the employed technology such as WiFi, CDMA, Wibro, and UMTS, a method that can provide efficient performance by combining a layer 2 handover procedure and layer 3 handover procedure is desired. 
         [0007]    In particular, since a fast handover method based on WiFi, CDMA, and Wibro is already defined, an FMIPv6 handover method that can carry out a layer 2 handover procedure in the UMTS network by using media independent handover (MIH) method is required. 
       SUMMARY OF THE INVENTION 
       [0008]    One object of the present invention is to provide an FMIPv6 method and an apparatus for the method, the method and the apparatus being able to deliver layer 2 handover information through MIH service to obtain efficient performance by combining layer 2 handover procedure and layer 3 handover procedure in the UMTS network. 
         [0009]    To achieve the object, the present provides an FMIPv6 handover method in the UMTS network, comprising obtaining lower layer information about a target RNS from a current RNS; obtaining upper layer information about a target core network from a current core network; establishing a tunnel between the current core network and the target core network by using the lower layer information and allocating the target RNS; and after allocation of the target RNS, transmitting a message notifying the target core network of connection to the target RNS and receiving packet data from the target core network. 
         [0010]    Also, to achieve the object, the present invention provides an apparatus for FMIPv6 handover in the UMTS network, comprising a communication unit for transmitting and receiving signals; an information storage unit for obtaining lower layer information about a target RNS from a current RNS through the communication unit and obtaining upper layer information about a target core network from a current core network; and a controller for establishing a tunnel between the current core network and the target core network by using information obtained through the information storage unit and allocating the target RNS and receiving packet data from the target core network through the communication unit. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0011]    The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the principles of the invention. In the drawings: 
           [0012]      FIG. 1  illustrates a UMTS network to which an FMIPv6 handover method according to the present invention is applied; 
           [0013]      FIG. 2  illustrates a flow diagram of an FMIPv6 handover method used in the UMTS network illustrated in  FIG. 1 ; and 
           [0014]      FIG. 3  illustrates a detailed block diagram of a mobile terminal for FMIPv6 handover in the UMTS network illustrated in  FIG. 1 . 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0015]      FIG. 1  illustrates a UMTS network to which an FMIPv6 handover method according to the present invention is applied. 
         [0016]    As shown in  FIG. 1 , a UMTS (Universal Mobile Telecommunications System) network comprises a mobile terminal  100 , UMTS Terrestrial Radio Access Network (UTRAN)  100 , a core network  120 , and a data network  130 . UTRAN  110  includes a plurality of radio network subsystem (RNS)  111  and the core network  120  includes a serving GPRS support node (SGSN)  121  and a gateway GPRS support node (GGSN)  122 . 
         [0017]    RNS  111 ,  151  comprises a node (Node B,  112 ) and RNS (Radio Network Controller,  113 ) and carries out the role of an access point. Node B  112  is controlled by RNC  113  and manages physical wireless connection to a mobile terminal  100 . RNC  113  manages dynamic resource allocation of wireless resources such as handover in a radio connection network. 
         [0018]    SGSN  121 ,  161  tracks the location of a mobile terminal  100  within service areas and takes care of various tasks such as packet routing and transmission, mobility management, logical link management, authentication, and billing. 
         [0019]    GGSN  122 ,  162  manages a connection function between SGSN  121  and a data network  130  and takes the role of a router. GGSN  122 ,  162  can transform GPRS (General Packet Radio Service) packets transmitted from SGSN  121  into the form of an appropriate packet data protocol (PDP) and transmit the transformed GPRS packets. 
         [0020]      FIG. 2  illustrates a flow diagram of an FMIPv6 handover method used in the UMTS network illustrated in  FIG. 1 . 
         [0021]    As shown in  FIG. 2 , first, a mobile terminal  100  measures signals of neighboring RNS and transmits information about measured signals to a mobile terminal  100  and a currently connected RNS  111 , S 200 . If a current RNS  111  requests information about measured signals, a mobile terminal  100  transmits a measurement report message to the current RNS  111 . A mobile terminal  100  can periodically transmit information about measured signals. 
         [0022]    Subsequently, the current RNS  111  detects a new RNS by using information about measured signals, adds an RNS that exceeds performance threshold among newly detected RNSs into a candidate set of RNSs, and transmits information about the RNS that exceeds performance threshold, namely layer 2 information to a mobile terminal  100  by including the information in MIH_Link_Detected message S 205 . 
         [0023]    Next, a mobile terminal  100 , to find target GGSN information about RNS included in the information transmitted at S 205  step, transmits RtSolPr (Router Solicitation for Proxy) message to a current GGSN  122  and checks layer 3 information about target GGSN by receiving PrRtAdv (Proxy Router Advertisement) message from the current GGSN  122 , S 215 . On the other hand, a mobile terminal  100 , by using layer 3 information about target GGSN, can create CoA (Care-of-Address) indicating location information of a network to which the terminal may move. At this point, the current GGSN  122  should be aware of information of a neighboring GGSN and RNS information included in the neighboring GGSN beforehand. 
         [0024]    Next, a current RNS  111  determines a target RNS  151  for a new handover by using information about measured signals transmitted from S 200  step S 220 , transmits a handover request message (Relocation Required) to a current SGSN  121  to carry out SRNS relocation procedure, namely layer 2 handover S 225 , and transmits MIH_Handover_Imminent message to a mobile terminal  100  to notify that layer 2 handover is to be carried out S 230 . 
         [0025]    A mobile terminal  100  establishes a tunnel between a current GGSN  122  and a target GGSN  162  to which a target RNS  151  belongs by using the target RNS  151  identified by MIH_Handover_Imminent message S 235 . To establish a tunnel between the GGSN  122  and the target GGSN  162 , a mobile terminal  100  transmits FBU (Fast Biding Update) message to the current GGSN  122 ; the current GGSN  122  that received FBU message transmits HI (Handover Initiate) message to the target GGSN  162 ; the target GGSN  162  that received HI message transmits Hack (Handover) message to the current GGSN  122 ; the current GGSN  122  that received Hack message transmits FBack (FastBindingAcknowledgment) message to a mobile terminal  100 . At this point, if the current GGSN  122  receives FBU message, the current GGSN  122  starts buffering packets received from the corresponding node (CN) and transmits the buffered data packet to the target GGSN  162  after a tunnel is established in response to receiving Hack message. 
         [0026]    Next, a current RNS  111  transmits MIH_MN_HO_Commit message to a mobile terminal  100  demanding the mobile terminal  100  to carry out layer 2 handover to a target RNS  151 , S 240 , As MIH_MN_HO_Commit message is transmitted, a target RNS to which a mobile terminal  100  carries out handover can coincide with a target RNS  151  determined by the current RNS  111  at S 220  step. As MIH_MN_HO_Commit message is transmitted, layer 2 handover, namely SRNS (Serving Radio Network Subsystem) relocation is carried out and a target RNS  151  is newly allocated to a mobile terminal  100 . 
         [0027]    Next, if a target RNS  151  is newly allocated to a mobile terminal  100 , the target RNS  151  transmits MIH_Link_up message indicating that a link has been upped to a mobile terminal  100 , S 245 . 
         [0028]    Finally, a mobile terminal  100  transmits UNA (Unsolicited Neighbor Advertisement) message to a target GGSN  162  indicating connection to a new RNS S 250  and layer 3 handover is completed by receiving packet data from the target GGSN  162 , S 255 . 
         [0029]    FIG,  3  illustrates a detailed block diagram of a mobile terminal for FMIPv6 handover in the UMTS network illustrated in  FIG. 1 . 
         [0030]    As shown in  FIG. 3 , a mobile terminal  100  comprises a communication unit  300 , an information storage unit  305 , and a controller  310 . 
         [0031]    A communication unit  300  is a module for transmitting and receiving signals, which can receive signals from a current GGSN  122  and a target RNS  151  and transmit signals to a current RNS  111 , a current SGSN  121 , a current GGSN  122 , and a target GGSN  162 . The signals can include messages or layer information, which can be in the form of packet data. 
         [0032]    An information storage unit  305  stores layer 2 information transmitted from S 205  step through a communication  300  and layer 3 information identified at S 210  step. 
         [0033]    A controller  310  establishes a tunnel between a current GGSN  122  and a target GGSN  162  by using layer 2 and layer 3 information stored in the information storage unit  305 , newly allocates a target RNS  151 , and receives packet data from the target GGSN  162  through a communication unit  300 . 
         [0034]    The present invention can be implemented in the form of program codes stored in a processor-readable recording medium. A processor- readable recording medium includes all kinds of recording apparatus to which processor-readable data are stored. Examples of processor-readable recording medium include ROM, RAM, CD-ROM, magnetic tape, floppy disk, and optical data storage. Also, a processor-readable recording medium can be distributed across a computer system connected to a network and processor-readable codes can be stored and executed in a distributed manner. 
         [0035]    It will be apparent to those skilled in the art that various modifications and variations can be made in the embodiments of the invention without departing from the spirit or scope of the invention. Thus, it is intended that embodiments of the invention cover the modifications and variations of this invention provided they come within the scope of the appended claims and their equivalents.