Communication Networks Research Lab by mikeholy

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									                        EE624
Mobile Communications Systems (MCS)



              Fall Semester, 2000

           Prof. Dan Keun Sung
    Department of Electrical Eng. and Computer Science
    Korea Advanced Institute of Science and Technology
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Chapter 10. System Architecture
 for Wireless Communications




         Continued
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                      Table of Contents

 TR-45 / TR-46 Reference Model
 Standardization of the MSC-BS Interface
   Supported Architectural Configurations
   Call Processing
   Radio Resource Management
   Mobility Management
   Transmission Facilities Management

 Services
   Basic Services
   Supplementary Services
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            TR-45 / TR-46 Reference Model

 The Cellular standards Group TR-45
 TR-46  PCS Standards Group
                                                            OS             AUX                IWF
                                                                                                          PSPDN         Rx
                                                                                                                             TE2


                                                                  O         X         L         PI
                 WPT0
                                   Base Station

            Sm   WPT1   Um   BTS      A-bis       BSC            A         MSC                      AI        PSTN      W    DCE       Rv
      TE1                                                                                                                                      TE2


                                                                                                    DI
            Rm   TAp                                    E
      TE2
                                                                       F             B                        ISDN       S
                                                                                               MI                            TE1
                                                                            C
            Rm   WPT2
      TE2                               MSC


                                                                                                              PLMN            TA        R
            MS                                                             HLR            D         VLR                                        TE2
                                          I
                                                    I                                                                          External Networks


                                        DMH                                 H

                                                                                                          G
                                                                 EIR       AC

                                                                                   Mobility Managers            Other
                                                                                 (Terminal & Personal)          VLRs




                             ( Figure TR-45 / TR-46 reference model. )
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  Elements of the Reference Model (Cont’d)

 Mobile station (MS)
 Base Station (BS)  Terminates the radio path
  and connects to the mobile switching center
   Base Transceiver System (BTS)
   Base Station Controller (BSC)

 Mobile Switching Center (MSC)
   Anchor MSC : The first MSC providing radio contact in a call
   Border MSC : An MSC controlling BTSs adjacent to the location of
    a mobile station


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Elements of the Reference Model (Cont’d)

 Candidate MSC : An MSC that could possibly accept a call or a
  handoff
 Origination MSC : The MSC directing an incoming call toward an
  MS
 Remote MSC : The MSC at the other end of an intersystem handoff
  trunk
 Serving MSC : The MSC currently providing service to a call
 Tandem MSC : An MSC providing only trunk connections for a call
  in which a handoff has occurred
 Target MSC : The MSC selected for a handoff
 Visited MSC : An MSC providing service to the MS
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  Elements of the Reference Model (Cont’d)

 Home Location Register (HLR)
   The functional unit used for management of mobile subscribers by
    maintaining all subscriber information (e.g., electronic serial number,
    directory number, international mobile station identification, user
    profiles, and current location)

 Data Message Handler (DMH)
   Collects billing data

 Visited Location Register (VLR)
   The functional unit that dynamically stores subscriber information
    (e.g., ESN, directory number, and user profile information) obtained
    from the user’s HLR
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  Elements of the Reference Model (Cont’d)

 Authentication Center (AC)
   The AC manages the authentication or encryption information
    associated with an individual subscriber

 Equipment Identity Register (EIR)
   The EIR provides information about the MS for record purpose

 Operation Systems (OSs)
   The OSs are responsible for overall management of the wireless
    network




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        Elements of the Reference Model

 Interworking Function (IWF)
   The IWF enables the MSC to communicate with other networks

 External Networks
   PSTN, ISDN, PLMN, and PSPDN




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    Interfaces Among the Various Elements
             of the System (Cont’d)
 BS to MSC (A-interface)
   Supports signaling and traffic (both voice and data)
   Defined using SS7, ISDN BRI/PRI, and frame relay

 BTS to BSC Interface (Abis)
 MSC to PSTN Interface (Ai)
   Defined as analog interface using either dual-tone multifrequency
    (DTMF) signaling or multifrequency (MF) siganling

 MSC to VLR (B-Interface)
   TIA IS-41 protocol specification


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     Interfaces Among the Various Elements
              of the System (Cont’d)
 MSC to HLR (C-Interface)
   TIA IS-41 protocol spec.

 HLR to VLR (D-Interface)
   TIA IS-41 protocol spec.

 MSC to ISDN (Di-Interface)
   Digital interface to the PSTN T1 interface (24x64 kbps) Q.931 signaling

 MSC to MSC (E-Interface)
   The traffic and signaling interface between wireless networks.
   TIA IS-41 protocol spec.


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     Interfaces Among the Various Elements
              of the System (Cont’d)
 MSC to EIR (F-Interface)
   EIR is not defined yet.

 VLR to VLR (G-Interface)
   TIA IS-41

 HLR to Authentication Center (H-Interface)
   Not defined

 DMH to MSC (I-Interface)
 MSC to the IWF (L-Interface)
   Defined by the inter-working function

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     Interfaces Among the Various Elements
              of the System (Cont’d)
 MSC to PLMN (Mi-Interface)
   Interface to another wireless network

 MSC to OS (O-Interface)
   Interface to the operations systems

 MSC to PSPDN (Pi-Interface)
   Defined by the packet network

 Terminal Adapter (TA) to Terminal Equipment
  (TE) (R-Interface)
 ISDN to TE (S-Interface)
   Defined within the ISDN system
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     Interfaces Among the Various Elements
                  of the System
 Base station to MS (Um-Interface)
   Air Interface

 PSTN to DCE (W-Interface)
   Defined within the PSTN system

 MSC to AUX (X-Interface)
   This interface depends on the auxiliary equipment connected to the
    MSC




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   Standardization of the MSC-BS Interface
                   (Cont’d)
 TIA IS-634 (MSC-BS Interface for 800 MHz)
   Defines MSC-BS messages, message sequencing, and mandatory timers
    at the base station and the mobile switching center
                                       Base Station                                                                                 MSC
              Supplementary Services




                                                                                                Supplementary Services
                                                                     Transmission Facilities




                                                                                                                                                       Transmission Facilities
                 Call Processing




                                                                                                   Call Processing
                                       Radio Resource




                                                                                                                         Radio Resource
                                        Management




                                                                                                                          Management
                                                        Management


                                                                          Management




                                                                                                                                          Management


                                                                                                                                                            Management
                                                          Mobility




                                                                                                                                            Mobility
                                                SCCP                                                                              SCCP

                                                  M TP                                                                              M TP

                                                                                  Physical Facility


                                                              ( Figure TIA IS-634 functions )
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    Standardization of the MSC-BS Interface

 Base Station Application Part (BSAP)
   Applications layer signaling protocol
   Base Station Management Application Part (BSMAP)
    : The BSMAP messages are sent between the BS and the MSC
   Direct Transfer Application Part (DTAP)
    : Messages are sent between the MS and the MSC




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 Base Station Application Part (BSAP) (Cont’d)

 The BSAP message are transferred over an
 SCCP connection
 The DTAP and BSMAP layer3 messages between
 the BS and the MSC are contained in the user
 data field of SCCP frames
 The DTAP messages apply only for mobility
 management and to call processing (including
 supplementary services) functions
 The BSMAP messages are associated with radio
 resource management and call processing
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Base Station Application Part (BSAP)

  DTAP Message Header                   BSMAP Message Header

  M e ssage Discriminator                M e ssage Discriminator


          DLCI


     Le ngth Indicator                      Le ngth Indicator




    Laye r 3 M e ssage                      Laye r 3 M e ssage




                  ( Figure Layer 3 data field )




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    Supported Architectural Configurations
            (TIA IS-634) (Cont’d)
 Transcoder
   Supports both voice coding (vocoder) and diversity reception
   QCELP format  PCM format for voice frames
   Data messages are bypassed
   Picks the “best” frame when multiple connections are established
    during a soft handoff




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Supported Architectural Configurations
            (TIA IS-634)

                   M SC




               Transcode r


                   BSC




                                         Uniquely identified by
             BTS          BTS         Mobile Country Code (MCC)
                                      Mobile Network Code (MNC)
                                     Location Area Code (LAC), and
                                           Cell Identity (CI)


     ( Figure Basic CDMA architecture )


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Call Processing and Supplementary Services




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      Radio Resource Management (Cont’d)

 Once a call has been established, the base
  station is responsible for maintaining a reliable
  radio link between the mobile station and the
  base station
   Radio channel management
   Initiation and execution of handoffs

 Soft Handoffs
   IS-95 Add Target Procedure
   IS-95 Drop Target Procedure
   IS-95 Drop Source Procedure

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Radio Resource Management




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         Mobility Management (Cont’d)

 Mobility management is implemented using
  DTAP messages
 The purpose is to support registration and
  deregistration of a mobile
 This function encompasses authentication and
  voice privacy




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Mobility Management




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 Transmission Facilities Management (Cont’d)

 The transmission facilities management
  function is responsible for the management of
  terrestrial circuits
 Terrestrial circuits are transmission facilities
  that carry traffic (voice or data) and signaling
  information between the MSC and the BS




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Transmission Facilities Management




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                  Basic Services (Cont’d)

 Registration and deregistration functions
   Automatic registration
   Terminal authentication and privacy (using private key cryptography)
   Terminal authentication and privacy (using public key cryptogratphy)
   User authentication and validation
   Automatic personal registration
   Automatic personal deregistration
   Personal registration
   Personal deregistration



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                     Basic Services (Cont’d)

 The registration and deregistration process requires that
  the PCS network communicate with the home PCS
  network to obtain security and service profile information
 Roaming
 Call establishment, call continuation, and termination
  procedures
    Call origination
    Call delivery (Call termination)
    Call clearing
    Emergency (E911) calls
    Handoff


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        Supplementary Services (Cont’d)

 Automatic Recall
 Automaic Reverse Cahrging (ARC)
 Call Hold and Retrieve
 Call Forwarding (CF) – Default
 Call Forwarding – Busy
 Call Forwarding – No answer
 Call Forwarding – Unconditional
 Call Waiting


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        Supplementary Services (Cont’d)

 Calling Number Identification Presentation
  (CNIP)
 Calling Number Identification Restriction (CNIR)
 Conference Calling
 Do Not Disturb
 Flexible Alerting
 Message Waiting Notification
 Mobile Access Hunting
 Multilevel Precedence and Preemption (MLPP)
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        Supplementary Services (Cont’d)

 Password Call Acceptance
 Preferred Language
 Priority Access and Channel Assignment
 Short Message Service
 Remote Feature Call
 Selective Call Acceptance
 Voice Privacy
 Subscriber PIN access
 Subscriber PIN Intercept
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            Supplementary Services

 Three-way calling
 Voice message Retrieval




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