Monday, November 12, 2012

Functions of the elements in the WCDMA network

  • Monday, November 12, 2012
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    •  Functions of the elements in the WCDMA network
    Element
    Function
    MSC
    The MSC is the softswitch center in a WCDMA network.
    It incorporates the VLR database. Its functions include:
    • Call control
    • Access control of MGW
    • Resource allocation
    • Signaling processing
    • Routing
    • Authorization
    • Charging
    The MSC is used to provide basic services, 
    mobility management, and multimedia services for subscribers.
    MGW
    The MGW incorporates the MRFP to convert the format of media streams, 
    play announcement, and provide conference resources and other media resources.
    UMG8900 incorporates SG functions and can realize signaling
     interworking between the IP bear and the SS7 signaling network.
    HLR
    The HLR is a database for mobile subscriber management. It stores the following information:
    • Subscription information
    • Subscriber states
    • MS location information
    • MDN
    • IMSI (MIN)
    GGSN
    The interface between the GPRS (General Packet Radio Service) network and external IP networks. The location register function in the GGSN stores subscription information and routing information (needed to tunnel packet data traffic destined for a GPRS MS to the SGSN where the MS is registered) for each subscriber for which the GGSN has at lest one PDP context active.
    SGSN
    The SGSN is an NE that provides the GPRS services. The SGSN forwards the input and output IP packets to the MSs in its service area. The SGSN provides the following functions:
    • Routing and forwarding of subscriber packets
    • Encryption and authentication
    • Session management
    • Mobility management
    • Logical link management
    • Charging information generation and output
    BSS
    In GSM, the BSS is composed of the BSC (Base Station Controller) and the BTS (Base Transceiver Station) associated with it. It is controlled by MSC, and used to give radio coverage to a determined geographical zone called a cell.
    UTRAN
    In UMTS, the UTRAN is composed of the NodeB and the RNC (Radio Network Controller) associated with it. It is controlled by MSC, and used to give radio coverage to a determined geographical zone called a cell.
    Based on the evolution strategy of the CS domain of the mobile CN and the requirement for constructing an all IP networking, the MSC in the GSM and 3GPP R99 is divided into two parts: the MSC server and the MGW in the 3GPP R4 and later versions.
    • MSC Server connects with the BSS and the UTRAN, and performs the following control functions of the CS domain:
      • Mobility management
      • Security management
      • Handover processing
      • Signaling processing
      • Call processing
      • Subscriber data management (function of the VLR)
      The MSOFTX3000 provided serves as an MSC server.
    • MGW is the transmission endpoint of the PSTN or the PLMN that is connected to the MSC server. It performs the following functions:
      • Media transformation
      • Bearer control
      • Coding/Decoding of digital signals
      • Echo cancellation
      • Conference bridging
      The UMG8900 provided serves as an MGW

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